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Comment by travisgriggs | Hacker News Reader

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

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.

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.

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.

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.

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