Starship's Third Flight Test [video] | Hacker News Reader

Starship's Third Flight Test [video]

spacex.com

499 pointsBenoitP395 comments

The test is essentially a success at this point. Starship can take payload to orbit and open/close the payload doors. The remaining things are icing on the cake. They can refine re-usability while flying payloads.

I think they also successfully demoed in-space fuel transfer.

Fuel transfer with what? That would require things like docking

They transferred something like 10 tonnes of fuel from one end of the ship to the other.

Transfer internally between tanks in the bottom and top of the ship. This was one of the planned tests, I have not heard whether it was accomplished though.

There was a callout saying that it was successful.

Edit: On the other hand tweets from Gwynne suggest that they still need to review the data to see if it was a success.

They performed an in-ship fuel transfer, from one chamber to another. My understanding is that this is a very important pre-requisite for an actual transfer from one ship to another, because of the need to keep the fuel at cryogenic temperatures during the transfer, which is apparently not easy. Last time it was done was decades ago, but in kilograms. SpaceX just demoed a transfer of tons of fuel.

Bigger problem than keeping it cryogenic is getting it to one side of the tank while in orbit, so the pumps don't run "dry". Harder than just doing an ullage burn first too, because moving that amount of mass around also moves the vehicle.

They used tanks inside the ship to transfer from 1 to another to prove the process, was discussed and called out as success, and talked about many times before the flight

Not quite: the apogee burn they had planned didn't happen (no word as to why yet), so the ship didn't technically demonstrate the capability reach orbit. It came back down in the Indian ocean on its original suborbital trajectory, essentially like an ICBM.

That is a matter of the trajectory they chose on purpose for this test flight. A different flight profile would have given them a perigee above the atmosphere (rather than -50 km)

Parent's (correct) point is that it isn't a matter of the ascent trajectory. They can't leave the Starship up in orbit, and where it reenters needs to be controlled.

> They can't leave the Starship up in orbit, and where it reenters needs to be controlled.

Why? Plenty of boosters re-enter uncontrolled and burn up all the time.

Stated simply: zero-thrust "orbits" repeat the same trajectory again and again. So if you end your burn in the outer atmosphere near your launch pad, the next time around you will be back in the outer atmosphere (near where the the launch pad "was", ignoring the rotation of the planet). And since there's air there providing resistance, you'll re-enter and crash.

Getting to orbit requires at least one more burn near the apogee of the original orbit to circularize it and ensure the spacecraft doesn't approach the atmosphere again. Starship didn't do the apogee burn they intended to do, so didn't demonstrate this capability.

Singe burn to orbit is pretty common though in reality, with the dynamics of staging, engine throttling, and precision insertion capabilities most modern rockets can hit the mark.

> Getting to orbit requires at least one more burn near the apogee of the original orbit to circularize it and ensure the spacecraft doesn't approach the atmosphere again

The Saturn V went direct to Earth orbit without requiring relighting the third stage engine.

Non-reusable boosters don't go into orbit and perform calculated crash into ocean soon after launch.

Small second stages and spacecrafts can be allowed uncontrolled orbital reentries because they usually burn-up. Starship is too big for that, debris would rain like when Space Shuttle Columbia disintegrated over land. They most likely will need to show engine relight capability to control reentry point before going orbital.

First thing that comes to mind: Starship has a lot of protection against burning up, so huge chunks of it could survive and cause damage.

Afaik, when talking about objects large enough that some debris will actually hit the ground, only China intentionally lets their final stage re-enter uncontrolled. Everyone else at least has a plan for controlling re-entry. SpaceX has lost control of some of their Falcon 9 second stages before, but that's the exception not the rule.

Ok so they could leave Starship in orbit and launch payloads like that. The idea however is to launch payloads WHILE testing reentry and landing. This requires an engine relight in orbit.

> WHILE testing reentry and landing.

> This requires an engine relight in orbit.

The latter is part of the test at this point of development

Starship is huge and heavy and made of steel, it will not burn up on reentry, if it falls on a populated area it will kill people. They will not be allowed orbital trajectories until they demonstrate they can control the deorbit burn.

An empty Starship has a very low ballistic coefficient, it will be torn apart by the atmosphere if not carefully controlled. Add to that the FTS and there is no real danger to population on the ground.

Of course it will not maintain its shape, but the pieces that land will be large.

It's made of 4mm thick steel sheets, and the FAA disagrees with you.

Columbia was torn apart by the atmosphere... and dropped huge chunks that were a danger to people on the ground-- some as large as a VW Beetle.

Typically American policy is to have a controlled reentry option for as much as possible. The disposable first stages of all rockets don't need a controlled reentry because they are always suborbital and thus their splashdown location is relatively well known ahead of time. The second stages are typically supposed to deorbit and burn up over water after a launch to LEO. There are occasional cases where something goes wrong and they fail to deorbit, which is when we sometimes hear of the burn up due to gradual orbit decay being witnessed over land.

I wouldn’t classify the re-entry survival problem as icing. But otherwise, I agree with you.

Yeah, breaking up in-air during re-entry (at 65 km going by last telemetry) seems like a potential big issue to fix.

The point they were trying to make is that getting up is MVP, getting back down can be figured out later

OP's point is that the tests become a bit cheaper and a bit easier to get licenses for since they can get to orbit and can deploy Starlinks. The reentry problems of course have to be fixed, but the FAA mishap investigation will involve fewer delays, just like how Falcon 9 was able to keep flying, attempting landings without having to wait for a mishap investigation to finish every time a landing failed.

Iirc F9 had its main challenge in that final suicide burn. Usually the boosters made it there just fine and then "only" failed to get the parameters aligned just right.

Based on what we saw today, the main chokepoint for Starship might be right in that hot reentry telemetry blind spot. Debugging without logs.

It sounded like they might have had flight data recorders on-board which might have survived through reentry with telemetry. If so, they'd have some logs, but yes, figuring out reentry will likely be the main challenge for now, not only is it hard to debug, even getting to it requires everything else to go more or less perfectly.

With all the solid state gizmos we have today, is it really that difficult to make a blackbox that can survive serious impact G-forces, especially if it just needs to work and doesn't need to be safety rated?

Unlike with F9, in this case they most probably had high-bandwidth telemetry all the way till the vehicle broke up (if the high-def video stream is anything to go by). So, they probably have a lot more data this time. Even the video can yield information - for example, given that the cameras were mounted on the flaps, they can probably back out the actuation angles from that.

Video feed interruption was very much expected, and went through a series of on/off before the final signal. From what we saw in the live presentation, both scenarios are possible: breakup while transmission was up, transmitting as long as latency allows, with hopefully good explanations in the log, or a disconnect from the challenging radio situation in the reentry plasma long before something went wrong.

Unless they do find some failure buildup in the logs they did receive, it will be difficult to tell disconnect due to breakup from breakup (long) after disconnect. Gradual signal loss on the receiving side would indicate that it's likely the latter, but I'm not sure a signal loss unrelated to breakup would necessarily be gradual. I'd guess atmospheric properties can change fast at reentry velocity.

In the livestream they mentioned that they lost signal on both Starlink and TDRS simultaneously, which is why they figured it had broken up at that point. They were prioritizing the telemetry over video frames on Starlink, and TDRS can only handle telemetry.

Thanks, must have missed that detail in the stream. Hope they find a good explanation candidate in the data!

it's the expected outcome of an imperfect (literally not precisely perfect) reentry. something went wrong. it could be a very minor thing like a stuck valve somewhere. we'll know in the next test if they figured it out.

> Yeah, breaking up in-air during re-entry (at 65 km going by last telemetry) seems like a potential big issue to fix.

That's what pretty much every non-SpaceX rocket does today with very few exceptions.

And indeed every spacex rocket. Starship is the second stage -- and a second stage on a F9 burns up in the atmosphere just as much as Starship from IFT3 did.

The big things to fix seem to be

1) The roll rates for starship (which prevented the inflight relighting test)

2) The Booster relights, which didn't have enough lighting to soft land.

Both of those feel like minor problems.

I'm amazed that the propellant transfer demo seems to have worked first time, and of course they managed to get the tihng up there in the first place.

The reusability of the Starship part of the system is a much bigger unknown, but that doesn't seem to be necessary for the next launch.

Wouldn't surprise me if the next try is by the end of April

bright side: booster made it all the way to splashdown

haha, it was travelling at 1100 km/h...

Not so much a splashdown but a smashdown :-D

to have been a fly on the wall... was surely a site to behold :)

Why? Saturn V broke up in-air during re-entry on every "successful" launch as does every ULA rocket.

Because that is their stated design goal for Starship.

And you don't need to meet that goal to start launching (risk-tolerant) payloads to orbit during their test flights. Especially with such a hardware-rich development program.

They have a great pipeline for building ships. They want reusability, but for near-term needs like deploying bigger Starlink satellites and their moon lander contract they could probably power through without reentry survival. It would be expensive, but unlike in-orbit refueling not really mission critical

My understanding is that Starship is financially comparable to Falcon 9 on a per-payload basis even if fully expended.

If so that would be amazing.

Comparable to Falcon 9? Unlikely - they've got three dozen Raptor engines on that thing, which alone account for the entire cost (not price) of a Falcon 9 flight. Maybe it is comparable to legacy launch providers, such as the Deltas and Atlases. But unlikely comparable to a Falcon 9 launch, even considering the larger payload.

In https://payloadspace.com/starship-report/ the cost of Falcon-9 launch is estimated as $15M. One Raptor is less than $1M, but full Starship has 39 Raptors.

Starship will be much more attractive when it will become fully reusable though.

You are launching 8x more payload vs ~15 reuses of Falcon9

the weights isn't the only upgrade, the SIZE is another very important metric....

They'll be able to get much larger objects up there without having to piece them together up there. Especially important for habitable objects and factory objects.

The current iteration of Starship has a payload bay door fit only for the Starlink satellite.

"The current iteration" is also just a proof of concept. Their published plans include fliptop and large bay doors. not to mention the HLS (Human Landing System) that includes an airlock.

That's what they aspire to. The only way to get there is if they are able to achieve reuse into the dozens of times and there's no guarantee they will be able to do that. I hope they are able to but there's still a lot of work to get there.

> but for near-term needs like deploying bigger Starlink satellites and their moon lander contract they could probably power through without reentry survival

Starlink sat deployment, probably. I’m not convinced on the moon lander contract though. Each mission requires the moon lander itself, plus a number of tanker launches to refuel the moon lander. I think it’s something like 8-15 tanker launches.

If each of those tanker launches is an expendable vehicle that’s… probably economically survivable, but definitely not sustainable.

Though, if the tankers are expendable they won't have to reserve fuel for the landing, and the number needed to refuel would probably be at the lower end of that estimate - maybe even 6-10?

If you can't reuse the boosters, then a series of Starship launches to the moon will cost as much as one SLS. The complex launch architecture demands reusability. It's a deal-breaker without it.

They can launch payloads that bring in revenue while working on that problem. There is a good chance they put a bunch of Starlinks on the next flight.

Exactly, they’ve reached feature parity with large expendable launch systems so they can piggyback paying customers with a high risk threshold (starlink) on flights they’d be doing anyways. Given their cadence this phase won’t last long, they’ll likely achieve at least one successful landing next flight.

They have also been eager to launch version 2.0 starlink satellites, but they don't fit in the falcon fairing. The first couple batches of those would be test articles as well, so I'd be surprised if the next starship launch doesn't a few on board.

They've been launching a version of the v2 sats that do fit in the Falcon 9 fairing and supposedly have all the functionality of the larger versions. The issue is that F9 can only carry ~24 of those at a time, which slows down the pace of expansion a lot.

The new 'Pez dispenser' on the starship is designed for the full sized V2 sats, which are about 2x the mass of the V2 minis.

Yes this would all be true, if it were true. It is likely to become true at IFT-4 but they are very demonstrably not quite where you say they are.

This was still a suborbital flight and they cannot do much of anything that is commercially practical on suborbital flights (like launch satellites, even if they raise their apogee). They appear to have not had good control authority in coast and reentry. They did not do a relight/deorbit burn test that is likely an obstacle to tackle before they can make orbital flights. I assume we'll get some confirmation about these things soon enough, but please, you can be optimistic without being hasty.

> This was still a suborbital flight and they cannot do much of anything that is commercially practical on suborbital flights

If they had flown a slightly steeper ascent and burned for a little longer (possibly a minute if not less), they would have ended in a stable orbit. Not doing that was intentional.

They do not need engine relight capability to reach orbit - plenty of orbital rockets exist that cannot relight their final stage.

Yes, but the point was that they can't launch starlinks or just about any commercially meaningful payload until they are reliably in orbit, and they can't reliably get into orbit until they demonstrate at least one relight, because they need to reliably re-enter the atmosphere for the reusability tests.

So they are at least one more launch away from launching starlinks.

> commercially meaningful payload until they are reliably in orbit,

Which then can do without a relight.

> and they can't reliably get into orbit until they demonstrate at least one re-light

And part of testing deorbit/landing capability includes testing that they can relight the engine.

So they could launch the next one with Starlinks (possibly test articles of those as well since no full-size V2 satellites have been laucnhed yet). Get it into orbit and include a deorbit burn/re-entry as part of the flight plan. If the latter part somehow still does not work out ... they still got Starlinks into orbit. And they now have more data to fix it on the next flight. They already have several vehicles lined up for static fires and flight tests.

They won’t put starship into orbit until they can test relight. They won’t risk, nor would they be allowed to risk putting it up there without a demonstrated ability to bring it back down in a controlled manner.

> They won’t put starship into orbit until they can test relight.

Why can't they test relight? Also, they are already filing paperwork for IFT-4:

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=cu...

"Application includes a sub-orbital first stage booster and an orbital second stage"

They can test relight, but my point was that they wouldn't do it with Starship in orbit, because if it doesn't work, then they have no idea where it's coming back down. But maybe that's not as much of a problem as I had assumed given what's stated in the FCC application.

> They do not need engine relight capability to reach orbit - plenty of orbital rockets exist that cannot relight their final stage.

I don't think SpaceX is interested in having uncontrolled Starship re-entries. It's large enough that (even without a heat shield) debris will very likely make it down to surface.

> They do not need engine relight capability to reach orbit - plenty of orbital rockets exist that cannot relight their final stage

I’m sure they will have this thing plez dispensing cybetrucks all the way to mars in short order. But I’m also pretty sure that the FAA and whoever SpaceX buys their insurance from are gonna need pretty good assurance that they can control where that thing comes down. Expendable orbital stages are designed and engineered for safe end of life operations and uncontrolled reentery. Starship is not.

They might do one to test deployment, but it'd be a throwaway. Their relight test was skipped (not said why), so they still don't have confirmation they can control where Starship re-eneters. Until that happens, it's very unlikely they'll target actual orbital velocity. The Starlink satellites do have thrusters, but they're ion engines, so not nearly enough thrust to get that last bit into orbit before they'd re-enter.

99% chance that they lost attitude control hence couldn't point the business end towards wherever they wanted to. we know they can relight the engine on the booster and we know they can relight for landing burns.

no surprise if the next launch has a couple pre-production big starlink birds.

On the contrary, they absolutely had attitude control. Otherwise reentry would have seen the ship tumbling out of control and quickly breaking up. Instead, SpaceX was able to begin a controlled reentry in the upright position, indicating nominal orientation performance.

they were tumbling, just slowly. they started reentering side first. that it broke at 65km was unsurprising - shuttle experienced peak heating about there.

I'm no so sure, it at least looked like it was tumbling before and throughout re-entry. If they had attitude control, I think they would have at least stopped the visible rotation at some point before re-entry?

I'm not sure why the ship not immediatly breaking up, but eventually breaking up is proof that they at attitude control - especially against what the live feed showed - rotation.

  > If they had attitude control, I think they would have at least stopped the visible rotation at some point before re-entry?

Maybe they thought the flaps would help stabilize once hitting some atmosphere. In fact, that seemed to happen though not before quite a bit of plasma cooked the unshielded side.

My bet on the re-entry failure is that they have really poor attitude control. They definitely had some, but you can also see at different points that the plasma was shifting directions. At T+46, it was doing a spin as the first plasma started to show. At T+47, it was going down on the edge of the heat shields. At T+47:40 it appears to be going down engine first.

Moreover, I'm guessing the reason they skipped the mock re-entry burn was due to not being able to settle the propellant. Though it's really hard to tell if the turning of the Starship was to rotate which side was getting heating from the sun, or if it was spinning out of (or with less than desired) control.

Tim Todd noticed that the gas thrusters were icing over and then releasing the ice. So it's a reasonable guess that this was part of the issue, but that's leaning even more into speculation territory.

I just noticed that I typed "Tim Todd" instead of "Tim Dodd". It's past the edit period so I shall forever live with this shame. In my defense, I was on 5 hours of sleep so I could watch the launch.

You are a contemporary yet timeless sort of gentleman. Well done.

I'd speculate one of main tank bulkheads breached and gas kept leaking from payload door which overpowered RCS. Then, during reentry, the vehicle briefly managed to regain attitude by aerodynamic forces on the flaps, but became north-northwest aligned and broke up.

> know they can relight the engine on the booster and we know they can relight for landing burns.

Do we know that? Booster crashed into the water at full speed; landing reignition failed.

They did demonstrate this during their Starship-only bellyflop/landing tests a couple of years ago. This wasn't in space, though, obviously, and wasn't after an extended coast period. So... we know they can relight them under at least some circumstances, but whether or not they can under _these_ circumstances is maybe unclear.

As long as it is profitable when thrown away, the math works. Remember, until Falcon 9, they were always thrown away (except for Shuttle). Even if not profitable in the short term, the delta between cost and breakeven is an R&D expense.

Payload able to be delivered to orbit safely and insurable? Ship it. The more you do, the faster you get better.

If their cost per kg to orbit, with total loss of both Booster and Starship, is substantially lower than any of their competitors - then it is success, and recovery is just icing on their profit margins. Er, cake.

(And would be very cool marketing and PR, obviously. Not that SpaceX has much need for either of those.)

No quite; even if 1st and 2nd stages deliver cargo to orbit cheaper than competition, you still has to make sure there is enough demand to pay back the cost of Starship creation. That demand may require not just being cheaper, but to being substantially cheaper than competition, to enable additional uses.

What SpaceX is doing with Starlink reminds of the situation with early versions of Windows, when, as Bill Gates described, the industry wasn't keen to produce applications for it. So Microsoft started writing Word and Excel in house. Similarly, SpaceX created Starlink which needs lots of launches, and which couldn't exist with previous level of launch prices, but is able to make profits if the prices are as low as SpaceX can provide.

Re-entry is icing because every other cargo rocket besides falcon, lands just like IFT3 lol

Artemis 5 only needs three New Glenn rockets. Artemis 3 and 4 need significantly more Starships.

One technical modification: They need engine relight in orbit to work to deliver payloads, otherwise Starship will stay in orbit and they can not test reentry.

You need a second burn just to enter orbit. You burn at the top of the sub-orbital arc (opposite side of the earth) to enter orbit.

No, that's inefficient and real spacecraft don't do that for typical low earth orbits. Works in Kerbal Space Program, though.

Normal orbital insertion is a single burn to orbit (with staging). With the correct initial roll and pitch, the spacecraft follows a perfect gravity turn and ends up in a near circular orbit at main engine cut off.

Do they typically burn softly until near apogee, then put on the power until raising the orbit on the other side to their current altitude? In KSP, I can easily get an orbit on a single burn (with staging) but getting it circular obviously requires adding energy at apogee.

No, most rocket engines have quite limited amount of throttle capability and run near maximum thrust until cutoff.

The rocket yaws and pitches in the first seconds of flight while the vehicle is still subsonic, then flies a gravity turn trajectory at zero angle of attack (facing the direction of travel) at near maximum thrust. Any errors accumulated during early part of the flight will be corrected by adjusting the timing of the second stage cutoff based on radar tracking.

The initial pitch over is just a few degrees off vertical, but must be precise to a fraction of a degree (KSP tolerances are higher due to small planet).

You can get a pretty good circular orbit in Kerbal Space Program with one burn if you do a few attempts and trial and error binary search for the optimal initial pitchover angle, but it's very difficult to do without throttling the 2nd stage burn. If I recall correctly, the MechJeb mod can do a precise single burn to orbit.

Thank you. Yes, I figured that real life engines could not throttle enough for the maneuver as stated. I am familiar with the gravity turn, but I just don't see how energy can be added continuously, uniformly right up to a circular orbit. But I've not really put much effort into trying to understand that, I'll start looking more at real life pitch angles at various altitudes. Maybe I just need to start that gravity turn sooner - you mention that it already starts in the first few seconds. Thank you.

In vanilla KSP1 with a reasonable orbital launcher, fly up to 1000m altitude and tap D on your keyboard 1 to 10 times. Then hands off until 2nd stage and then throttle down to avoid overshooting the apoapsis.

Finding the correct number of key taps to get the right pitch angle is the key. The throttle can only help so much.

Will do, thanks. 1000 m is in fact much lower than I usually pitch. Off the pad I've been giving just a touch of pitch to ensure that the rocket is on the right trajectory, but didn't start the gravity turn until maybe 5000 m or so to get out of the thick atmosphere sooner. Yes, I would have quite the AoA for a little while.

Thank you. Though I don't expect to open KSP any time in the near future, I love to know how the real rockets do it.

1000m is much higher than real rockets pitch over, but good for KSP with forgiving aerodynamic stress. It's just a convenient round number and gives a few seconds of breathing room to make sure the fiery end of the rocket points to the ground before start of maneuvering.

I do remember the Shuttle pitch and roll real early, though I thought that was to point the antennas (K-band was it?) at the receivers.

The roll is to change the orbital inclination, the pitch is to set ascent trajectory.

Got it, great. Much appreciated!

MechJeb + Realism Overhaul offers a "Primer Vector Guidance" ascent controller that (I think) is based on the space shuttle's Powered Explicit Guidance. It's definitely designed to work with more realistic spacecraft; it can ullage with RCS, doesn't need to throttle, etc.

IIUC real launchers do a single burn to orbit because S2 TWR is not very high and relight is finicky. Launchers that has relightable S2 and/or hypergolic S3 routinely do circularization burns.

There are reasons "apogee" is more recognized word than "apoapsis".

> There are reasons "apogee" is more recognized word than "apoapsis".

What are you getting at? The -gee suffix means Earth. Apogee is apoapsis of an orbit around Earth. People playing KSP speak of apoapsis because Kerbin isn't Earth.

IRL they always did and therefore discussed "apogee kicks" after payload release into elliptical transfer orbit(literally GTO). That's where I'm getting at.

If you think about it, there can't be an ellipse that intersects a circle while also being fully encompassed by the latter. That's to say the periapsis can't be higher than the maneuver altitude that the off-apsis burn takes place as the other guy is suggesting.

On real rockets they add small shelf-stable stage such as the spinny boi Star-48 or the notoriously narcoleptic Fregat, inside fairings between S2 payload interface to actual payload, or let the payload pull itself into the final orbit at a great expense.

Yes, you can keep the S2 burning all the way to Ap and then burn at -45deg at Ap to deform the ellipse back into a circle, or fly a by the book gravity turn trajectory, but that's not the most energy efficient insertion, only what are situationally beneficial when there is land below and acceleration is limited.

They do this while performing the burn of the (in this case) 2nd stage. "No, that's inefficient" is misleading, IMHO. They also waste some delta-V by starting the circularization burn a little bit early.

You surely know that, but mathematically it is unavoidable to have a 2nd burn at the apoapsis to have an orbit (with a periapsis > the initial launch altitude, minus gravity and atmospheric losses), albeit it may start earlier (while wasting a slight amount of delta-v).

> You need a second burn just to enter orbit

Not necessarily - it is completely dependent on the ascent profile. For example, during the Apollo program, the Saturn V would fly directly into a parking orbit and only relight the S-IVB for the Trans-Lunar Injection burn.

I'm not sure the payload doors successfully opened and closed. Anyone have more details?

I heard the announcement about the door opening and saw - what I assume to be - live images from the inside which showed the door first opened, then closed so it seems that test worked.

Scott Manley seems to believe that there was some kind of malfunction with the doors[0]. I couldn't really tell from the video, but he certainly knows a hell of a lot more in this domain than I do. He does agree that overall the test was highly successful though.

[0]https://youtu.be/8htMpR7mnaM?t=512

Here's an evaluation of things going wrong on the flight by three 'Youtube space flight watchers' (Fraser Cain, Scott Manley and Marcus House) including possible mishaps with the cargo door:

https://www.youtube.com/watch?v=EVic941kQ44

Here's a fun thought, how many Starship launches would it take to put the equivalent mass of the ISS up in the same orbit?

The ISS weighs ~420 metric tons. That is 2-3 expendable launches or 3-4 reusable ones.

Jesus Christ, that really puts it into perspective what a game changer starship is

Now do the same calculation in units of hubble space telescope and james webb space telescope masses.

Then look at expected reusable launch cost and figure out how many HSTs or JWSTs we could have put in orbit for the same cost.

JWST would also be incredibly less expensive if it didn't have to do the very complex folding required by smaller rockets

JWST would still have been an extremely novel and therefore expensive on Spaceship. We just don't build anything that uses that kind of sun shield or those sensors etc and everything needs to work on one shot, thus serious engineering effort.

With Starship flights it should be the right combination of cheap enough, frequent enough, and big enough to enable whole new paradigms of construction in space.

We'll be able to design modular space telescopes that benefit from economies of scale, so that we'll be shipping up the sun shield in separate pieces anyways so if any particular one is lost that's okay we'll have an assembly line to produce more.

Launching several doesn't solve the issue of needing a design and construction that actually works. For something nobody has ever built before and we can't really test in zero g without launching etc.

Unfolding the heat shield was a relatively minor design issue compared to say the instruments, we just had less ability to actually test it on the ground.

How much larger could we have made it still doing the folding on starship?

I have no idea. Ariane 5 rocket has payload dimensions of 15x50 feet. Starship is 26x56ft. The unfolded mirror is 21 feet across, so if you increased that by 73%, then 36 feet. This is all probably really unfounded assumptions

The benefit of starship here is probably being able to massively reduce the expense and risk of future JWST duplicates that don't need to fold. Also in the launch cost, which was $1 billion for Ariane 5 whereas Starship would be in the tens of millions.

Launching JWST on Starship would still be incredibly expensive because JWST is at the Lagrange point on the other side of the moon and 1 starship needs like 30 other starships to fuel it to get there

How do you explain how the Ariane 5 used for the JWST, with a mass to GTO half that of Starship, was able to position the JWST without 60 launches?

Simple, it’s designed to launch a payload into lunar orbit and starship isn’t. To move something using starship into lunar orbit you need to move an entire starship there while the Ariane 5 is designed to do it in 1 launch at the expense of much less payload capacity and no reusability.

I still don't follow. The Ariane 5 launched the JWST with enough fuel to get where it's needed. Starship can launch the exact same payload, plus twice the entire weight in extra fuel. Starship also offers no-reusability launch options for stuff just like this.

Not just the capacity per launch but the cost per launch also.

for comparison, building the ISS took 40 assembly flights [0] (36 of them from the Space Shuttle)

[0] https://en.m.wikipedia.org/wiki/Assembly_of_the_Internationa...

How many launches are required to land on the Moon?

Depends on what lunar lander hardware is being used. If we were using Apollo hardware:

Apollo LM: 16 metric tons (landing about 5 tons on the moon)

Apollo CSM: 29 metric tons

The third stage of the Saturn V, called the S-IVB, (which was used for the trans-lunar injection burn) weighed 123 tons - however this was also used to get into the initial orbit.

Starship can launch 150 tons to LEO in reusable mode or ~200 mt when expended. The Saturn V was able to launch 141 tons to LEO. So it should theoretically be possible for Starship to launch an LM+CSM stack with an S-IVB with enough fuel for a trans-lunar injection burn. Then fly the rest of the mission as in Apollo.

Or we can refuel the Starship a few times in LEO using a bunch of re-usable flights and land 100 tons of payload on the lunar surface. The latter is probably cheaper and simpler at this point.

According to this: https://youtu.be/OoJsPvmFixU?si=Df6Eq9uq6IJCApUs&t=1730

Six... eight... more like twelve... at least 15

Big things they still need to hit are soft splashdown of both stages because recovery and reuse are critical to the economics of Starship. From the stream it looks like they had barely any engines light during the landing burn and I could see several missing tiles on the second stage. Way fewer were missing though which is a bonus, last time they were visibly missing a lot of tiles even before they lost the stage.

Well, the second stage definitely needs to survive re-entry if it wants to carry passengers. But it seems to work as-is for orbital cargo.

Passenger rating isn't even in the cards for Starship for a long time. You ride to LEO on a Falcon-9 with a proven track record for the foreseeable future.

"Foreseeable" is roughly "five years"? Starship HLS (Human Landing System) is currently planned to land on the Moon, with people, in 2026. It may very well slip a year, two or three - but landing on the Moon this decade still seems quite possible. Or you consider "passengers" different enough than "crew"?

Yes, landing on the Moon without an atmosphere is vastly different from orbital flight on earth and has an entirely different risk profile.

Interesting Asterix on that is the humans will only be on Starship from Lunar orbit down to the moon surface and then back to lunar orbit again.

No humans aboard during Starship launch, transit to and from the moon or re-entry.

(For completeness, humans will do all that other stuff aboard SLS and Orion. Starship literally only ferries them down the moon and back up again)

Yes, but HLS is just one example. In, say, ten years it may look very possible that Starships with people will fly on LEO. Is it beyond foreseeable future?.. I just don't understand why such a pessimistic estimate.

In my view, since I was the one that said it, anything more than 5 years away is perpetually 5 years away until it's been proven. Yes, eventually when Starship has enough launches and a track record it will get human rated by NASA to carry astronauts. This is the only actual certification for human space flight worth paying attention to right now. It's possible to get on a rocket otherwise, but the US government isn't going to pay for the ride. Getting flight certified by NASA is expensive and requires a level of experience with the vehicle that doesn't make sense for at least 5 years given we have a cheap and safe ride to LEO via Falcon / Dragon. Nobody is going to rush human flight on Starship, it's only going to have people on it once it's already in space.

I'll still take this as progress. With thermonuclear reactors it's perennial 20 years, similar for flying cars, in-house robots, manned flight to the Mars, so 5 years as a stand-in for "foreseeable future" sounds like a good step ahead.

I just looked it up.

The first Falcon 9 flight was June 2010.

The first Falcon 9 with astronauts was May 2020.

10 years to get human certified.

That was also with a rush order on it due to the Shuttle's retirement.

Good point.

In those 10 years Falcon 9 flew 84 times [1].

So I would think Starship needs to fly roughly a similar number of times before it will be human rated. Even if they launch one a month from now on, it will take ~7 years. So I think we're a while away from NASA certifying Starship for human flight, though I wonder in SpaceX would just put their own people on it regardless.

[1] https://www.popularmechanics.com/space/rockets/g32758515/fal...

Maybe the words "success" and "failure" are too difficult to shoehorn into describing these tests, especially with the first two tests.

"Great progress" is a good intermediate.

When you write a test case, you define what "Passed" means. If this test flight overall meets SpaceX's definition of "Passed", then it was a success, regardless of what anyone else thinks it should mean.

If your test case for left pad passes when it outputs a string of the right length, your boss is going to judge whether it's a good test case. Since this is all being done on federal grant money, it's legitimate to have higher expectations. This test was good, though - the previous two were disappointing.

Holy cow. How are people downplaying something so revolutionary. Without those other tests SpaceX wouldn’t have done what it did today and they show progress each step. They are doing what nasa couldn’t (send stuff to space orders of magnitude cheaper) because they aren’t afraid to blow stuff up.

They haven't gotten to the revolutionary part yet (fuel tankers in orbit, raptor relight, reusable first stage, reentry).

Re-using rockets isn't revolutionary?

I think it might have been back when the shuttle did it in 1981.

The shuttle that cost 450 million per launch? (And disposable boosters)

The boosters parachuted to the ocean and were reused. Only the external fuel tank was not reusable. However, you're correct that the Shuttle failed utterly to realize the point of reusability, that being low cost and quick turnaround.

Moving the goalposts. I didn't say it wasn't revolutionary either, just that they haven't gotten to that part yet.

Nobody has done anything revolutionary and nobody has gotten to space an order of magnitude cheaper. The best estimates of SpaceX's cost advantage per kilo put it at 30-50% better than a Soyuz.

The Starship program so far has soaked up as much money as SLS, and hasn't even left orbit.

They did several revolutionary things with starship:

Full-flow staged combustion metholox engines.

Stainless steel construction.

Biggest rocket to have ever flown.

Highest thrust at launch of any rocket by a factor of two or so.

Live streaming of reentry via a space Internet network.

Etc…

Those all sound like incremental technology advances to me that have yet to deliver any real advances in capabilities. Which is nice - don't get me wrong - but not exactly worth rolling out the aircraft carrier for.

Someone else in this thread pointed out that Starship could get the ISS built in just 3 launches! It originally took dozens.

Quantity has a quality all of its own.

You should be familiar with this from IT: there’s nothing fundamentally different about the first computer that I’ve ever used to the one I have right now, other than the factor of a million difference in performance!

Starship today can't launch anything. Saying that it can launch the ISS in 3 launches is what Elon Musk says it can do. I don't trust Elon Musk's word for things until I see what someone does with those words. Generally, he is off by a factor of 10-100 on his promises.

> Starship today can't launch anything

Why not? With the capability demonstrated today, they can just as easily tweak the ascent profile to end up in a stable orbit outside the atmosphere. Their trajectory was suborbital on this flight on purpose.

Well, for one, the payload doors don't work.

Full flow methalox is absolutely revolutionary.

> The Starship program so far has soaked up as much money as SLS, and hasn't even left orbit

There's a bit of nuance to what you are claiming here.

SLS cost $11B to develop, which is estimated to be in the neighborhood of what Starship will cost when development is complete. We don't know how much has been spent so far.

A huge difference is that producing and launching an SLS rocket costs over $2B, while SpaceX is estimating $10M for Starship. Now, I don't trust that $10M number, that's what they aspire for it to cost. To do it they need to be able to reuse the stages dozens of times. It could take a long time to achieve that or they might not make it at all. However, $2B+ per launch is a whole 'nother level of expense.

I think each test served exactly its purpose and it's incredible to see the rapid progress. Unclear why you believe the first two were not a success at all? Did you expect a novel vehicle like this would just work the first time?

I do. SLS, Vulcan, and most other rockets from reputable space companies have worked first time.

Those are also:

- More expensive than Starship, or

- Took longer to develop than Starship, or

- Are significantly less ambitious than Starship

(and those are definitely not exclusive ORs)

Going by total program cost, both of those are cheaper than Starship. SpaceX does this sleight of hand where they don't count their R&D cost in their calculations, but they do count it in other peoples' programs when comparing. SLS so far is about $2 billion in, and Starship seems to be at $2-3 billion. Vulcan is way cheaper than both.

- Source for Vulcan total program cost? All I can find is their per-launch pricing. Tory Bruno himself apparently said that "new rockets typically cost US$2 billion, including US$1 billion for the main engine."

- Not sure where you're getting the SLS number, the GAO report at https://www.gao.gov/assets/gao-23-105609.pdf claims, "Since 2011, NASA has spent $11.8 billion to develop the initial SLS capability."

- I think the marginal cost is a fair question. The whole party line out of NASA was that this time Moon exploration would be sustainable. If each trip costs > $1B before you even put a payload on the rocket that's a big problem.

I completely agree with you on marginal cost, but I don't believe SpaceX to provide accurate numbers for their own rockets before they are actually built (they love wishful thinking) or their competitors' (making your competitors look bad is better for you).

Okay well respectfully I looked at the number you provided for the closest comparison rocket, SLS, and it was 6x too charitable.

SLS flight cost is $2B. Each launch. Did you forget to include the decade prior? It's so expensive that it can fly no more than once a year. The next flight is scheduled for Sep 2025, three years after the first flight. I bet you think that isn't absurd.

SLS use leftover engines from the Shuttle era. Yet it still cost 160 millions. Each. Thrown away after each flight.

Vulcan is a conservative design with no reuse. It also uses BE-4 engine, which costs them nothing to develop.

The word reputable was an interesting choice to describe Boeing. It also carries a bold implication that the space company shuttling astronauts to and from the ISS—only two days ago [1]—is… disreputable? Meanwhile, Boeing Starliner certainly didn't perform nominally on its first orbital flight test [2].

Space flight is hard and different testing methodologies are no silver bullet. But, I suppose we will know them by their fruits.

[1] https://en.m.wikipedia.org/wiki/SpaceX_Crew-7

[2] https://www.washingtonexaminer.com/?p=802006

And the Saturn V

I wonder, who decides which space companies are "reputable" and based on which criteria.

It is quite a manipulative word to use.

The test flights have been right in line with how spacex does development and testing. I’m confident that everyone involved with granting them that money knew this going in.

It's fine that they've not yet completed any stated launch objectives in three tests and have, amongst them, 5 independent catastrophic vehicle loss events because that's what we expect out of SpaceX.

> Since this is all being done on federal grant money

Its true that SpaceX has gotten federal money contract for landing on the moon to the tune of $2.9B. But the Starship program is going to cost a lot more than that, Musk estimated $10B and has done stock offerings to raise money. And you have to take into account that the federal money has to support 100% of the moon specific parts of development.

So, its true that the feds are helping w/ Starship development but "all" is not accurate.

the open and close of the payload doors was a failure.

Not that i think its a big deal... but its important to acknowledge failures so we can learn from them.

T+37: Seems a little turny-aroundy in orbit there

and a bit "small-pieces-falling-offy"

Still, good job getting it there

T+43: seems to be turning around a bit too much for something thats got heat shields on one side and is about to re-enter

T+45: flaps moved, maybe that is supposed to get it the right way round, I get it now - it uses the flaps to orient for re-entry

T+46: the little bits of debris must be tiles coming off

T+46: flap glowing red, can see plasma (edit: spacex tweeted a video of this bit, its quite something https://twitter.com/SpaceX/status/1768279990368612354 note the camera position moves because the camera is on one of the forward flaps)

T+47: "biggest flying object ever in space" uh-oh

T+47: serious re-entry flames

T+48: loss of signal

T+54: still no signal

T+62: saying they lost signal via starlink and TDRS at same time so maybe that was the end of it

T+65: confirmed lost during re-entry

T+67: the presenters all eat a large pie. each.

I'm still in awe that I got to watch a reentry live stream just now. I wish I could tell my child self what wonders were in store. Watching humanity progress in real time is amazing.

Kids. I got to watch a moon landing live. (Not a stream, and crummy resolution, but still...)

[Edit: I meant to be talking smack a bit, but don't let me ruin your enjoyment of the really amazing things that are happening now.]

Yeah, it's pretty awesome to watch "the first" of something! I wasn't born early enough to watch the moon landing, but I did watch the livestream of the first successful landing of a Falcon 9. Watching that bit of science fiction turn into reality was one of the more memorable moments of my life.

It's all good, I feel like we're all kids when we wonder about the universe

>T+46: the little bits of debris must be tiles coming off

Seemed like ice to me, which itself can be it a problem. The vehicle didn't seem very stable even before this point so I'm wondering if we're getting ice build up on the cold gas thrusters which changed the control dynamics keeping the ship from flying stably.

Yeah could be. Some of the debris looked very specific in shape though. On some shots of starship you can see missing tiles (not many though)

It looked to me like a good portion of the debris was in fact tiles. It also seemed to me that there were significant attitude control deviations, both of which might have been significant factors in the unplanned disassembly event.

Right after the engine cut-offs for the second stage from the first burn you can see at least one tile missing and during the burn before that I also saw some dark flecks fly off.

It certainly looked like there was either a fairly continuous firing of the cold gas thrusters, a stream from the second stage engines, or some atmospheric effects from being in such a low orbit.

those plasma views when starship was coming into atmosphere were absolutely mind blowing.

it makes a lot of sense to use starlink for this, but it never ever crossed my mind.

Having those plasma views in livestream. It is incredible.

Yeah, in HD. It's sci-fi stuff.

As of today, it's the new normal!

The new norminal!

Just like the first belly flop video.

The thirty seconds from 1:00 are unreal.

https://www.youtube.com/watch?v=gA6ppby3JC8

That's incredible.

Plasma blocks all EM radiation. That's why livestreaming plasma views is so incredible, not just because views themselves are nice.

yeah that was really cool, it looked like an artist rendition of what it could look like hah. I'm looking forward to high-res photos of those views.

The booster puncturing spheres of clouds on a way back was awesome also.

That was my highlight of the test: live video of the biggest rocket booster hitting the ocean at 1000km/h.

video: https://twitter.com/SpaceX/status/1768279990368612354

Note the camera moves because its also on a flap

Indeed! I just want to thank SpaceX for giving me yet another "This looks like insane Hollywood special effects but it's real" moment.

I was just watching Spacex official stream and at ignition they switched to Musk hawking cryptocurrency. What just happened??

edit: wild I just realized take off is 50 minutes from now... what had I been watching?? they did a countdown and there was ignition... was that a time wrap? Am I going insane?

edit2: @spacex034 is not @spacex... today I learned...

SpaceX does not stream on YouTube, you are watching an old launch on a fake channel. Please report them.

Dang I got got. Thanks for letting me know

You weren't the only one, I clicked on it too, as did thousands of others, before finding a real stream

YouTube does a bad job of real time takedowns of spoofed live streams. You’d think for big events like this they would have somebody just standing by and monitoring social stuff so that things like this don’t happen.

Then again you'd think one of Amazon's 1.5M employees would have the job of finding fake USB sticks for sale on the site, but apparently nobody has that title either.

> You’d think for big events like this they would have somebody just standing by

This implies that YT has humans that are not in sales. It feels like YT just has bots building more bots at this point.

Is that new? Because SpaceX has streamed launches on YouTube for years.

Yes, the official stream is only on Twitter now.

They also stream the launch live on the spacex.com website.

Thank you

I tried signing up for twitter but gave up at the "match these dice with these symbols (1 of 10)" stage.

It's not a great interface compared with youtube etc, not rewinding etc, but at least it works

That’s a Twitter embed on the SpaceX website. It’s still streaming from Twitter.

but no Twit...er, X account required

I will be deep in the cold cold ground before I recognize Twitter's new name

you see how I refer to it. it gets both names in there, and expresses the disdain and the confusion all in one go.

They did that for IFT-2 and the first channel I went to was one of those crypto bullshit things too. Very dumb decision on SpaceX's (well probably Musk himself) part.

Musk decided that Twitter is now a video platform and he's decided to dogfeed with SpaceX.

Twitter was a video platform before Musk took over. They were doing Thursday night football (NFL) and other things.

Looking at the SpaceX feed, they seem to be using whatever tech they got from the Periscope acquisition (at least the servers were still pscp.tv).

Twitter was not a video platform – it had (some) video features. Very different. And people always considered Twitter videos to absolutely suck.

That hasn't really changed though. He's just decided to manifest "Twitter is a video platform" into existence. The controls are still total ass though.

Yes just to be pedantic, twitter has never been "a video platform" – but that they've had support for streaming live events for years.

So take with that whatever it means, that it's just not going to be as first-class citizen like in Youtube. But the CDN etc must be good enough as those things are easier to do nowadays.

you were not watching the Spacex official stream?

There's a fake SpaceX YouTube account that looks official because they included videos from the real channel in playlists to get verification ticks & have managed to harvest thousands of subscribers. YT's interface is a bit dumb for including the verification ticks in that use-case.

YT's interface fights negative feedback harder than a spoiled toddler.

Hiding downvotes, squirreling the "block channel" feature into a dot menu, breaking it completely on recommended pages, and then breaking search pages... it's almost like they don't want to fight spam.

They're in the ads business - watched hours = money.

Why remove spam and clickbait when it means less money? Youtube is the stereotype of post-hype company that is just milking its users to increase their bottom line, driving the entire product to a slow death.

They get paid to serve that spam. Why would they reduce the avenues to serve the spam?

> looks official because they included videos from the real channel in playlists to get verification ticks

That is not how it happens. The account is verified because it is a stolen account that had lots of subscribers & views. They hide/delete the existing videos & rebrand the channel. It famously happened to Linus Tech Tips last year after a staff member fell for a spear phishing attempt.

You got bamboozled by an AI Elon deep fake.

Oh man and I had just downloaded the top result when searching app store for bitcoin wallet to send him bitcoin so he would double it for me!

Wait, double it? Would you please link me?

Screw that! I'll triple any BTC you send to this address: fjreisorhsksjshsjsjsj

I'm sorry sir, but my software won't take that address, a typo? Please resend.

this is probably exactly why x started doing video. youtube is so full of fake channels that it readily presents fake ones at the top of search results.

the x stream has been great and had a far greater reach (2.5 million) than any of the youtube streams by a factor of 10x or so.

Twitter is awash with garbage too, likely even worse. Every major account, without exception, has multiple fake clones (often many created per day) running around trying to steal clicks and occasionally phish users. The Internet is just hard.

You're just saying that the Twitter official account is official. No reason you can't have an Official Account anywhere else, SpaceX just doesn't.

when you search spacex on x, you are presented the official account first.

when i searched spacex on multiple youtube apps this morning, i couldn't even find the official spacex account after going through pages of menus.

Again, because there is no official SpaceX feed on YouTube, they deleted it. Can you link to the channel you think you should be seeing?

To be clear: if you search for "SpaceX" on Google, you get the corporate website as the first link and the Twitter account as the second. But YouTube has nothing to show you, by SpaceX's choice.

This is what shows up for me: https://www.youtube.com/spacex

you are searching channels. that is not available on, the roku app, for instance.

if you search by channels on x, for fair comparison, there are no spoofed spacex accounts to be seen anywhere. https://twitter.com/search?q=spacex&src=recent_search_click&...

NSF had 1.5M views on their stream, Everyday Astronaut had 1.8M views.

ya theirs a shitload of fake spacex streams with AI generated crypto scams

Dude, we encountered that yesterday. Somebody really figured out how to successfully pretend to be a spacex livestream! It was super weird, right?

Looked very impressive and there is enormous progress compared to the earlier tests. Especially as all engines seemed to work throughout the entire launch, the earlier tests had significant engine troubles so they seem to have a handle on that now.

The reentry burn failing doesn't seem like a huge deal in this case, especially as the engines worked very well earlier.

Its still an issue because they haven't really confidently demonstrated a relight of the engines while flying.

Hot staging avoids a relight, but they still need to do it.

It does mean they technically have an expendable heavy launch vehicle though.

The boostback burn demonstrated relight today.

The key demonstration is “relight in a vacuum”, which was the test that was skipped late in the stream. If you can do this then deorbiting is possible. Relight of the booster doesn’t demonstrate this, unfortunately.

> It does mean they technically have an expendable heavy launch vehicle though.

That is how they started using Falcon 9 as well: first expendable but testing recovery - which failed several times in several interesting ways - until that process was refined into what now seems to be a normal thing: the first stage launches, drops off a second stage, turns around and makes its way back to either the launch site or a floating platform. I assume they have the same plans for this system: launch expendable while using the hardware to refine the process of recovery until in not that many years from now they launch and land and launch again.

It's in orbit!

("...and we have a callout for nominal orbit insertion...")

edit: Not actually in orbit! This is a suborbital flight. Mea culpa

Technically its suborbital

Isn't orbit above 125 miles (200km)?

Orbit is when you drop an apple off a dining room table - it’s just a very crappy orbit.

“On orbit” typically means in a stable orbit around a body - but in the case of starship, it could have been on orbit, the delta v is more than sufficient, but that’s an unsafe configuration if you don’t know your engines will relight.

Orbit is mostly about speed, not about height. Going straight up and down doesn't count, even if you pass the height that some orbital vehicles attain.

This vehicle is actually going orbital speed, but not quite orbital height (or rather, it's in an "orbit" that has a very eccentric elliptical shape that would cause it to hit the atmosphere on its way back around; it'd be well above a typical orbital height at apogee, though).

Technically you can orbit the earth at a pretty low speed. Geostationary satellites orbit about 5,500kph, which is far slower than the 26,000kph starship reached today.

You just need to get high enough, and be pointing in the right direction.

Orbit is when you turn the engines off and stay up there.

Space is generally defined to be 100km above earth's surface, an arbitrary point called the Karman Line [1].

Orbit is when an object is traveling so fast that it reaches the horizon of a body before the body's gravity can pull it down to the surface, but perpetually. It's basically perpetually falling around the body. Imagine one of those guys in a wingsuit skimming along the surface of a mountain, never actually touching the surface. It's similar to that, but at a much higher scale.

1) https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line

Orbit is a speed, not a distance. You could do a suborbital hop that has its highest point beyond the orbit of the moon. (if you aim very, very well)

At the same time, if your velocity vector is pointing towards the ground you're not achieving orbit no matter your speed

It works if you're a black hole or a chunk of degenerate matter. For transatmospheric orbits being a large ball of iridium will work too.

It's in space (above the Kármán line), but not in orbit. Orbit implies it has the velocity for staying in space, which isn't the intention here. If anything goes wrong they want to be able to not leave junk in orbit

It's at 26000 km/h which sufficient for orbital velocity. It looks like it's in an elliptical orbit. I guess we'll see soon if they need to do a de-orbit burn, or if the orbit just intersects the atmosphere and they use atmospheric braking?

I did the math. So, the minimal orbit at 180 km, the one that grazes the earth's surface at its perigee, is about 7.75 km/s or 27,900 kph. The other commenters are right: it was never technically orbital.

edit:

    (let* ((μ 398600.0)     ;; km^3/s^2
           (r 6371.0)       ;; km
           (peri (+ r 0.0))
           (apo (+ r 180.0))
           (a (* 0.5 (+ peri apo))))
      (sqrt (* μ
               (- (/ 2.0 apo)
                  (/ 1.0 a)))))
    ;; 7.745844595118488

Thanks! On one of the feeds, it sounds like they didn't want to leave a bunch of debris in orbit if they had an anomaly

> 26000 km/h

> 27,900 kph

Seems like they want to test the limit. Same speeds as LEO, but guaranteed to come down.

That is really cool. For those of us that are space nerds but don't have the depth of understanding, do you mind walking us through the calculation above?

I apologize I don't have a good explanation of it at hand! It's a form of the vis-viva equation [0] that's basically a restatement of conservation of energy. It derives the (scalar) speed of an object in a 2-body orbit, at any position within that orbit, as a simple function of their separation distance.

In the form I'm using, I'm using standard parameters of an elliptical orbit: the periapsis (the closest approach to the center of mass of the massive body (which is a focal point of the ellipse which the orbit traces)), apoapsis (farthest distance), and semimajor axis (their arithmetic mean [1]). I'm evaluating the orbital velocity at the highest point, the apoapsis. μ is a short form for the product G*M, the standard gravitational parameter [2] of Earth (which is known to much higher precision than either the universal gravitational constant G, or the mass of the earth M, individually).

The particular orbit I'm applying it to is one whose periapsis is equal to the Earth's radius—an orbit that touches the surface of the Earth. This is the dividing line for orbital / suborbital: a suborbital trajectory is one that (mathematically) goes beneath the Earth's surface.

[0] https://en.wikipedia.org/wiki/Vis-viva_equation#Equation

[1] https://en.wikipedia.org/wiki/Semi-major_and_semi-minor_axes...

[2] https://en.wikipedia.org/wiki/Standard_gravitational_paramet...

No apology needed, thankyou very much!

But it would have been if they executed the burn in at a slightly different angle.

Technically it's a transatmospheric orbit. That is, an orbit such that it'd stay up there if the atmosphere were not present. The difference between this and full orbit is just a few seconds longer burn, so it's a difference with little meaning in terms of proving out the ability to reach orbit.

I don't believe that's the case—see the math in my sibling comment.

The number going around from people who typically do this kind of thing is a ~55x235km orbit: https://twitter.com/planet4589/status/1768270310199935299

I'm not really in a place to judge your math right now to really add anything on that.

Yeah, that guy's absolutely a domain expert! But note that he writes -55 km, not +55 km—that is a suborbital trajectory. Its perigee is below the earth's surface; -55 km is a negative altitude.

(He's also clearly using a different set of data than I have access to. I can't read the context of the Twitter thread so I don't know what numbers he's looking at).

Ooh that's a good catch, I subconsciously substituted the -55 for ~55!

Close enough. If the ship had to ignore the flight plan and press to orbit, there's no doubt that it would've succeeded.

https://en.wikipedia.org/wiki/SpaceX_Starship_integrated_fli...

Mission summary including timestamps

> Raptor in-space relight demo | No attempt

That was a big one to not attempt. Why didn't they attempt it?

Possibly because they partially lost attitude control.

"Starship did not attempt its planned on-orbit relight of a single Raptor engine due to vehicle roll rates during coast"

https://www.spacex.com/launches/mission/?missionId=starship-...

FR24 shows a Dassault Falcon 900EX doing circles around the expected Starship re-entry location (Perth to Perth flight plan):

https://www.flightradar24.com/MXJ/345b8f09

Not looking good - Returning to Perth now.

From a safety perspective, how does that work?

This is obviously a test, and safe to say the vehicle was out of control and not entirely predictable. I realize they wouldn't fly into the actual predicted landing area, but just being close must be a risk.

Would the flight crew on that plane literally be scanning the sky above them to make sure they're not in the direct path of whatever comes down at whatever speed?

If onboard computer would sense that Ship is going somewhere it should not be it would trigger FTS (Flight Termination System) and destroy it with debris falling into Atlantic Ocean (exclusion zone was there as well).

Once Ship finished burn it simply had to land in predicted landing area in Indian Ocean, it did not have enough fuel on board to significantly change trajectory even if computer went crazy.

I guess some risk analysis can be made with the plane's and Starship's cross-section.

Let say they are cubes of 30m each. The expected area where they might both be present to be a 5km square. That's a 0.000025 chance of collision at most; and I suppose the plane is away from the center of the expected Starship Gaussian. I'd personally ride in that plane and risk that, even to just to get a glimpse of the reentry.

that.... makes a lot of sense. Thanks.

Somehow I was thinking it was super risky to be in the general area, but your numbers show that is clearly no the case.

Interesting that there was a flight sent to be in the splashdown area. My guess would have been there's not much engineering/scientific benefit to getting in the neighborhood of the splashdown. Maybe some footage could be gotten just for curiosity but at this early stage of re-entry testing of such a new and different vehicle I suspect the odds of being close enough to acquire decent air-to-air visuals would be pretty low.

Maybe the flight was an attempt to get close enough for a stored telemetry downlink post-rentry blackout but pre-splashdown?

Hahah, the elevator music while they wait for reentry...

I actually have the stream open in the background, can't believe how happy and calm this music makes me while patching servers :D

Came here to say exactly this :) great choice of music!

If you like that here's a protip: search for bossa nova instrumentals on youtube for soothing tropical background music

Ahh, beautiful, thanks! :D

Sounds like the perfect music to calm down in the evening or while cooking.

or soma.fm secret agent radio (lots of bossa nova)

My dad seems to love soma.fm, because he mentions it every time we talk about music :') Guess I have to check it out now.

Many many stations there

Music with intermittent control updates was great, reminded me lofi ATC exists (lofi music with airport control tower audio)

https://www.lofiatc.com/

My first thought was "This sounds vaguely like the music on the radio in Portal. Does a future SpaceX become Aperture Science? Is Elon Musk the progeny of Cave Johnson?"

When: 8:25 AM CT

Launch window: 7:00 AM CT - 8:50 AM CT

--- Updates:

(future)T+40: Starship relight and entry

T+12: Elevator music engaged, please stay tuned for T+40

T+11: Payload door testing

T+8: Upper stage SECO, nominal orbit insertion

T+7: (mine) KSP moment for booster reentry, instabilities. Signal cut off because of exhaust conducts electricity and absorbs RF. Status unknown

T-11: Still no blockers. Watching winds, may have hold at T-40s.

T-30: Broadcast started

T-60: (SpaceX Twitter) The Starship team is go for prop load but keeping an eye on winds, now targeting 8:25 a.m. CT for liftoff

T-65: (SpaceX Twitter) Shifting T-0 a few more minutes to give boats time to clear the keep out area, now targeting 8:10 a.m. CT

T-65: (SpaceX Twitter) New liftoff time is 8:02 a.m. CT, team is clearing a few boats from the keep out area in the Gulf of Mexico

T-45: No blockers

T-90: (SpaceX Twitter) Weather is 70% favorable for today’s third integrated flight test of Starship. The live webcast will begin ~30 minutes before liftoff

---- Streams:

High Quality VLC: Open VLC, Media, Open Network Stream, paste following, Play:

(higher quality) https://prod-ec-us-west-2.video.pscp.tv/Transcoding/v1/hls/g...

(lower latency) https://prod-ec-us-west-2.video.pscp.tv/Transcoding/v1/hls/g...

NASASpaceflight: https://www.youtube.com/watch?v=RrxCYzixV3s

Spaceflight Now: https://www.youtube.com/watch?v=EfnkZFtHPmM

Everyday Astronaut: https://www.youtube.com/watch?v=ixZpBOxMopc

LabPadre Space: https://www.youtube.com/watch?v=LMyXho_YCK8

(FR) Techniques Spatiales: https://www.youtube.com/watch?v=BRXfWLVMEQ8

---- Mission profile:

https://www.spacex.com/launches/mission/?missionId=starship-...

---- Links:

https://twitter.com/SpaceX

https://twitter.com/elonmusk

https://old.reddit.com/r/spacex/comments/1bb8scf/rspacex_int...

Pretty sure the first YouTube link you provided is some scammy fake stream.

Updated, Thanks!

Thanks, I like the Spaceflight Now commentary the most. Best analysis.

I find those youtube channels far too grifty for my tastes. Sadly as twitter doesn't seem to work ("Something went wrong. Try reloading.") I have lost quite a lot of the excitement I used to have for spacex.

I've been listening to SFN for about 20 minutes now and haven't heard a single reference to donations. Like parent, they're my preferred feed.

If you can get SpaceX's twitter to work, you can use them for audio. If so, EverydayAstronaut will likely have the best video.

What’s grifty about nasa space flight? They’re a private news org that does incredible coverage of SpaceX and spends funds doing as such. They’re mostly donation driven but they don’t solicit them really. They just thank folks that do on their livestream. Their forums are an absolute goldmine of knowledge if you take a look and it is an incredibly friendly community.

Whenever I've seen them (not sure which specific ones) they've been either

1) Whining about donations (and shoutouts every few seconds)

2) Whining about the cost of cameras (I remember one of the early exploding and the commentator spent the next 10 minutes going on about his expensive cameras)

Yes they are funded by begging, that's not something I'm interested in listening too. I've seen US TV occasionally, I find it unwatchable with the jarring commercials, but I guess if you are used to that then the begging streams.

The spacex stream traditionally is a good feed, not too fanboyish, no begging, but it seems it's no longer reliably broadcast

The official SpaceX hosts often don't mention when something goes wrong or looks bad. For example, they didn't comment on the ongoing tumbling of the ship. Of course they want to present themselves in the best possible light. Other streamers are more independent, they do point out those things.

I think the official hosts avoid it because they don't want to have potential speculation be treated as a fact. Mainstream media reporting around these launches is already mostly garbage in quality, having the hosts speculating might make it worse.

Like, Starship was tumbling, but until we saw that it didn't manage to maintain the orientation for reentry, it was possible that the tumbling and venting was expected.

Well, first off, they’re not NASA (or the NSF). I always thought it was sketchy that they used the name, it seems to imply that they are official when they are not.

i get the same message, but if you log into twitter then it says the stream will begin at 5:52am PDT

It's SpaceX's problem that they're not where the public expect them to be.

VLC stream links hit the spot for me... I was really hoping to see the official stream but twitter is... well... not what it used to be. Anyway thanks!

The URL on the „VLC“-links look a lot like „Periscope“ which was acquired by Twitter long ago. Maybe this is actually the official Twitter stream itself?

Whatever the infrastructure spacex is using for the stream, the twitter front end doesn't load for me. That's what I meant.

edit: now it loads but it has 10s delay so I'm sticking to VLC

You can watch the stream directly from the spacex.com website.

Now this one isn't loading on my side. And I got gigabit fiber at a major European city close to a big exchange.

That's just the embedded twitter stream :D

It is, how to reproduce:

Twitter stream page, F12, network tab, look for m3u8 file, right click, copy url, open in VLC

The nasaspaceflight streams are pretty good too. I like their commentary.

https://www.youtube.com/live/RrxCYzixV3s?si=1MFBk8yzD3VcRdWk

1000 km/h booster impact at sea, call that a "soft landing/splash down". Poor fishies :)

I guess they didn’t want to make it too easy for some Chinese fishing vessels ;)

Chinese fishing vessels in the Gulf of Mexico?

They are on vacation.

On shores of Africa, in Gulf of Mexico... yes, in 2024 ships can travel far

Probably even in Lake Superior.

I was going to write that a boat could get from the ocean into Lake Superior without ever entering the United States (by hugging the Canadian side of all lakes and rivers), but it appears that there is a dam on the St Lawrence River near Cornwall Ontario that forces you to take a short <10 mile detour through a river/canal in New York.

Illegal fishing by Chinese fleets is now commonplace in Africa, in Argentina, etc [0], so given how much they've expanded operations over the years it's only a matter of time before you see them there too, if it hasn't happened already.

[0] https://www.nytimes.com/interactive/2022/09/26/world/asia/ch...

Some species are rare. You need to look in the right places if you want to catch some fine raptors.

Hopefully the NASA flight monitoring the launch has video of the booster coming back down.

The WB-57 was not in the air today.

It does look like it came down rather fast. Engines only partially re-lit. About 34min in this video

https://www.youtube.com/watch?v=NWM1NQ1tZEU&t=2112s

I think that's the ascent burn. It doesn't look like the engines re-lit at all for the descent. (I imagine they aren't supposed to light until they're a lot closer to the ground than they were when the video was lost.)

At altitude 22km superheavy was moving at 4310 kmh (34:18 in linked video) speed then dropped continually, at 34:45 in the video the icons show that 3 engines were lit, altitude was 1km and speed was 1300 kmh. At 34:49 you can see flames, speed continues to drop, then you see the sea rushing up, then it cuts

Ah, I was thinking about Starship. I forgot that the booster attempted simulated landing was going on at the same time.

Going for fueling, launch scheduled with 25min left in the window (getting tight) (8:35CT). Watching wind speed.

That re-entry video was quite amazing and beautiful.

Very excited for this as usual, and thanks to a few delays, I won’t be on the train at T-0.

As for expectations, I’ll be thrilled to see Starship reach orbital velocity. Last time was so close. Engine restart and intact reentry? Even better but maybe more of a stretch? Fears? Only that it doesn’t do as well as IFT-2. And that’s always a possibility.

Also commuting around this :) Looks to be very successful. I wonder how many tests the ship can pass in orbit.

What an amazing effort. Best of luck to team SpaceX. I really hope both ships survive all the way to the ocean this time.

I was surprised that during the initial ascent footage from the fin-cam, you can see that the grid fins are out. Do they not fold back on ascent? Or possibly drag on one side to arc over? Just seems weird to have your “drag device” deployed during ascent.

They're control surfaces, they help keep the pointy end up and the flamey end down

They fold in/out on Falcon 9, but for the starship booster the decided it's not worth it. The extra weight and complexity to fold them in/out doesn't provide enough of a benefit. Elon talked about it a couple of years back on one of Everyday Astronaut's videos.

Grid fins aren't drag devices. They are control surfaces. As long as they are oriented so the fins are aligned with the airflow, they have no effect on orientation. The benefit of not folding them in is one less part that can fail. There might be a slight reduction in drag by folding them in, but not much and apparently not worth it.

I'm guessing 33 Raptor engines won't feel the effect of whatever drag those fins might produce. Instead, they'll just drag that drag into space

The side edge of the grid fin may have more surface area than edge on.

Not sure they can turn that far.

I'm saying if you could fold the grid fin, the surface area presented may be as high or higher than the surface area presented when unfolded.

I think that between the high TWR allowing the vehicle to spend less time in the thicker parts of the atmosphere and the lower pressure 'wake' the ship on on top would produce, there isn't as much drag over the fins as one might think. IIRC it was one of their various "delightfully counter-intuitive" discoveries during earlier testing.

Mind-blowing stuff. Breathtaking to be honest. Live video is such high quality. Sci Fi made real.

Looks like Starship lost but so much farther than before. This is incredibly exciting stuff.

For an uninformed person like myself - what's the expectation for this launch? Is it expected to explode like the last two?

They are hoping to achieve a hard landing in the ocean.

Given the progress shown between the first and second integrated test, odds are decent that they'll achieve it, however they are also trying for a number of firsts in orbit so who knows.

Well, yes, but the question is when.

If everything goes right the booster will likely explode when it lands in the gulf . Starship itself will most likely explode on reentry somewhere over the Indian ocean.

Now, I think the question is, will it explode before then, and of course that's why they do flight tests to find out.

Replying to myself. Booster made the boost back burn successfully and had a mostly controlled flight into the gulf. I say mostly because it looked like it had some instability and met the water somewhere close to 1000km/h if telemetry was right (or went unstable just before then).

10 minutes into flight starship is coasting in space for the next 30 minutes and should relight at around 40 minutes.

the instability was due to partial engine relight

It looked to me like there was some major oscillations shortly before the engines relit though.

Yea. If I had to make an uneducated guess I'm thinking one of two things.

1. Starship is leaky. Outgassing and/or leaky valves made attitude control difficult and used up ullage gasses quickly.

2. Thrust control/RCS has programming or physical issues. Saw a lot of ice breaking off places near deorbit, so if you had ice building up and redirecting gas the ship wouldn't perform as the computer expects.

Unfortunate that it was lost on re-entry. Super glad most of the mission was a success.

It got much farther than IFT-2, and exposed new problems, which is the purpose of a test flight. This seems like a success.

Things will only be bad if some problem is exposed that doesn't look solvable.

I'm happy they have some data with respect to re-entry. It would have been nice to see the vehicle survive for longer, but there's something to go forward with.

Beautiful flight so far!

Did anyone notice at around T+30:16 the cargo door was almost shut when it looked like it popped out of place. Then the view suddenly switched to an external camera.

Am I wrong?

Yeah, seems like something that needed to be closed even if it were on the cool side of the reentry.

The elevator music during this next 30 minutes in orbit! lol

Flawless launch.

Man this has me crying like a baby. I do not know why.

It's flying! And all engines are burning, it's pretty damn impressive to see this thing lift off.

Starship has reached orbit!

man, so much progress from the first two test launches. starship is alive and well, and the booster almost made it to soft water landing.

Breathtaking stream.

So FAA cleared SpaceX and then within a few days they completed their launch pretty successfully by all accounts. So does that mean SpaceX could have launched a while back with no issues and were just waiting on the FAA? Did the FAA literally just slow down progress?

Not a good look on the FAA, they should just let SpaceX do what it does at the speed they want. If they cannot add any value to this engagement, the least they can do is to not subtract value.

When you're launching the largest and heaviest rocket ever made not running headlong into creating the biggest fuel air explosion is part of the regulatory agencies job. The first launch was pretty wildly out of control so everyone wants to make sure the rocket explodes when told if it doesn't go where it's supposed to.

I think you touch on the issue of managing public perception as part of the FAAs job.

In general the public is not monolithic when it comes to this. Many people would ecstatic with the biggest fuel air explosion and thought Launch 1 was great while others were aghast.

Some people even think rockets shouldn't be developed at all.

As a result, you see regulators trying to find a line between covering their asses from blowback from different groups of constituents.

It's a bit of a complex interplay. If the FAA were finishing their investigations very quickly, SpaceX could be more aggressive with their testing. But on the other hand, as SpaceX gets a better read on how long the FAA might take, they time their readiness to when the FAA will be done.

For example, here they waited ~1 week between Starship being ready and done with a wet-dress rehearsal. If they knew that the FAA would be finishing earlier, they'd try to get through the WDR earlier. But since there's plenty of other development and testing to do on the ground, they just do that in the meantime.

The FAA delays were more of an issue around IFT-1 because they really couldn't proceed on much without knowing how all the big systems they built would perform, they would've been working blind (and considering how the launch infrastructure needed further strengthening, doing too much more without that data would've probably been a waste of money). That isn't really the case now, while they wait on the FAA they can focus on the payload bays, refining the control systems, building the second launch tower etc.

> Did the FAA literally just slow down progress?

Doesn't appear so, no. https://en.wikipedia.org/wiki/SpaceX_Starship_integrated_fli...

> On March 5, 2024, SpaceX announced that they were targeting a launch date of March 14, 2024, pending regulatory approval. On March 13, 2024, the FAA granted the launch license for IFT-3.

Anyone have a non youtube link please?

SpaceX does not stream on YouTube anymore. You can always get the official X broadcast link off their spacex.com launches page. Here's the one for today:

https://www.spacex.com/launches/mission/?missionId=starship-...

thanks, I had to unblock twitter.com on my firewall, lets see if it starts up [edit] up and running, great!

FWIW, this seems to be the m3u8 link of that stream: https://prod-ec-us-west-2.video.pscp.tv/Transcoding/v1/hls/g...

Wow, the re-entry is almost as exciting! hopefully the ship got the heat shield rotated into position again. I wonder why they dont cover the whole rocket with them if they are as light as they demonstrated. Amazing watch anyway, thanks.

Placing the heat tiles is (currently) entirely manual, and is very time-consuming. Starship is big.

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