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Comment by ChuckMcM | Hacker News Reader

This is a better article on the recovery than the one I linked from TechCrunch.

I would like to reiterate the point made before which is that SpaceX is on the verge of being in a place that no company has ever been before with regard to space.

The are on the cusp of having a capsule that they can send into orbit for days and then return to Earth. They already have rockets capable of putting tons of material into every orbit level (Low, mid, and geo-stationary). SpaceX is also nearing completion of their own launch facility in Texas.

When all of those things are added together, SpaceX can do space 'tourism' like nobody else. They could offer a 'day trip' on a Dragon into orbit. By partnering with Bigelow Aerospace[1] they could launch a habitat into orbit where they could ferry their own paying customers to spend a week in space. With their own launch facility they are freed from the scheduling hassles of the dozens of other clients who compete for space on those launch pads.

That would definitely feel like living in the future to me.

[1] https://www.bigelowspaceops.com/

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They are unlikely to do this at this point.

The big problem is that while the capsule will be reusable, since NASA killed the propulsive landing for Dragon 2, it now needs to splash down in saltwater and therefore is not considered safe for humans after the first use.

This makes Dragon 2:s too expensive for large-scale space tourism. Unless there is suddenly a huge market for this, I think SpaceX would prefer to sell interested space tourism customers flights on Starship instead.

That's interesting. I always assumed that most of the damage happened on re-entry and not the splashdown. Can you elaborate on why the splashdown kills re-use?

I'm guessing its the salt water that is the problem.

"Although water retrieval has been attempted, it is not recommended due to the adverse effect that salt water has on avionics, electronics, and structures. This approach was abandoned due to the elevated cost associated with refurbishing salt water damaged components. By avoiding water retrieval, the engines would avoid maintenance that would have resulted from the corrosive nature of the salt water and thereby expedite turnaround time. When considering recovery of reusable systems, salt water is much more severe than returning to land at the launch site."

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...

This is related to rocket engines, not ballistic descent capsules.

Ballistic descent capsules such as the Dragon have rocket engines in them.

True. However some capsules have rather small engines, and small available delta-v, so the whole propulsion package can be made, say, replaceable. Soyuz, for example, lands using only about 30 kilograms of hydrogen peroxide to help with control during reentry. Maybe Crew Dragon can evolve to have this subsystem serviceable.

just create a movable water pool for the ocean.

http://news.mit.edu/2015/shockwave-process-desalination-wate...

I live by salt water. Salt water destroys everything. Sometimes quickly but always eventually. Ok, maybe not fish.

It's really true. In your home it'll even happen to your indoor stuff if you're not careful.

Carbon steel hull ships traverse saltwater for many decades however.

What's their maintenance like?

Scrub/repaint every few years?

In comparison, splashdown capsules spend maybe few hours tops in the water.

The problem is that, unlike ships, they're generally not designed to be water proof. It's not the exterior that's the problem.

I mean, the crew part of it is water proof, right? It has to be air tight...

I'm guessing there are things on the "outside" that might still have issues?

> ... there are things on the "outside" that might still have issues ...

... on the second reentry attempt.

The first part of your post reminded me of this quote from Futurama.

Professor Farnsworth: Good Lord! That's over 5000 atmospheres of pressure!

Fry: How many atmospheres can the ship withstand?

Professor Farnsworth: Well, it was built for space travel, so anywhere between zero and one.

They use cathodic protection which makes the underwater hull basically immune to corrosion. But this doesn't stop water that gets on top or inside.

Ships rust like hell. I've known some guys in the Navy and they said it was common for everything unarmored to have holes all over.

I'm not disagreeing with the idea that Musk would shoot for using Starship for tourism, but I also think that I wouldn't put it past SpaceX to continue toward qualifying a reusable Dragon 2.

They are already getting good experience (and can experiment with) Dragon Cargo capsule re-use to better understand the impact of salt water landings on their designs. And while it would be hard to find space for the landing struts to go back into D2, if that meant doing a parachute landing with a last minute landing burn similar to what Blue Origin has proposed in their sub-orbital offering and is currently used on Soyuz, I could see that working with a landing in Texas.

What amazes me that this seems like a "small" amount of engineering to go from where they are, to a capability that was previously considered impossible by many. I'm sure it is way more complex than I realize, but they have some so far from where they started.

I wonder if they could catch the Crew Dragon with Mr Steven instead of water splashdown? No loss if they miss, and less refurb if they succeed.

Mr Steven is designed to catch fairing halves which weigh just under a metric ton. A Dragon capsule weighs 9.5 tons and can carry up to 7 people or 3 tonnes of return cargo, so it’s from 10 to 13 times heavier than a fairing half.

Metric ton sounds redundant to me. Does the US have the notion of a "imperial ton"? (1000lbs?)

Yes, tons do differ. A metric ton (or tonne) is 1000kg. In the US what’s commonly referred to as a ton is a short ton, or 2000 lbs.

An imperial ton would be the British one, also known as a long ton. It's 2,240 lbs, which is slightly heavier than a metric tonne.

> continue toward qualifying a reusable Dragon 2.

Pretty unlikely. To have it landing on land would be incredibly difficult specially to qualify.

Also they already have Starship and Starlink as huge projects they have to finance. They will make as much money as possible of Dragon 2 with the flights from NASA and invest that money in Starship.

Starship could actually be useful for tourism.

Why did they force the requirement for saltwater splashdown?

IIRC they were concerned about having retractable legs beneath the heat shield so in terms of complexity the water landing is safer.

No, that’s not it. The Shuttle had them and the engineering is easy. NASA was wary of the safety of propulsive landings and the time/cost to approve them would have been too much.

I am curious about this as well. Was the propulsion the problem? Did they just want a water landing? Did they specifically want an ocean landing to increase the acceptable margin for error in the splash down location? Is there some specific property to the salt water like buoyancy that is important? Would a landing in fresh water like the Great Lakes (or Lake Victoria if they need something more equatorial) meet NASA's requirements and allow the capsule to be reusable?

+1 for splashdown in the great lakes. Now let's throw in launch pad on the shore of lake superior for getting in polar orbits. ;-)

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

So yah they didn't reach orbit but you betcha it was still pretty neat to see it.

> Would a landing in fresh water like the Great Lakes (or Lake Victoria if they need something more equatorial) meet NASA's requirements and allow the capsule to be reusable?

I'd guess that one of the big reasons they (and everyone else who does water landings) lands in the ocean, is that it is much more palatable to regulators to create an exclusion zone in the ocean, which people can easily route around.

Also, people live on the side of the lake, so there isn't much margin for error, which never warms the cockles of a regulator's heart.

I'd also wager that the concentration of vessels on the great lakes is significantly higher than 100 miles or so out into an ocean. Wouldn't want to land on a sailboat. Don't think that'd work out well for either end.

This is Space X.... let's go for a splash down in a water park in Wisconsin too!

Eventually, SpaceX will improve the accuracy so much that they will be able to get random celebrities to pay for having splashdowns in their private Beverly Hills swimming pools. :)

where did you hear that dragon 2 is not safe for humans after splashdown? that's not accurate

Can confirm it’s not accurate.

thank you for the confirmation trashaccount123

I think the issue is more that it's not guaranteed to be safe than it's not safe. Salt water is corrosive. It might take a many times more exposure to salt water than a single landing for it to severely damage it, but it still gets rid of the guarantee until they study it more.

You know, it's like how once you put a boat into water once, it's unsafe for humans...

Any news on this? I was super, super disappointed this mission did have a propulsive landing. I'm just now finding out it was nixed entirely.

But that's fine for NASA if they want to pay for a splash down? If somebody else wants to pay for propulsive landing, it's on the table?

EDIT: Sounds like a SpaceX driven decision.

As I understand it, originally SpaceX was planning on using propulsive landing with side-mounted thrusters and legs coming through the heatshield (i.e. what was planned for Dragon 2) on Mars, so they were developing the technology with that end in mind.

Once they decided to go straight to Starship/BFR with the movable 'wings' and raptor engines on the bottom and cancelled the dragon missions to Mars, there was less reason to go though the huge amount of work to finish developing and qualifying dragon-style propulsive landing. NASA was never super happy with it and Dragon was designed to do water landings with parachutes in case the thrusters failed anyway, so it wouldn't have been too much work to make that the only option.

This has lead to a strange situation where it seems Boeing's Starliner has ended up being more reusable than Dragon as it comes back onto land... But if they get Starship going, all this will be irrelevant.

Cargo Dragon will give them the chance to experiment with refinements to the parachute and rockets for zero risk. There should be no reason why they can't do Soyuz style rocket assist landings.

Expense. NASA won’t pay for it and SpaceX is focused on Starship.

> NASA killed the propulsive landing for Dragon 2

Are you sure NASA was to blame for it? I remember Elon saying they are not perusing propulsive landing anymore because of the amount of resources it would take to develop and validate the design. From what I gather, it was SpaceX's decision.

Combined decision. NASA was unwilling to pay for testing propulsive landing, or allow testing on cargo missions, because the parachutes already work, and SpaceX didn't want to front the money themselves.

Falcon 9’s landing on land tech can’t be used in dragon?

No, it's not reliable enough. Energiya considered powered landing for Zarya capsule https://en.wikipedia.org/wiki/Zarya_(spacecraft) and felt it wasn't safe to land this way.

How big of an area could they splash down in? Could they target Lake Victoria, being the largest freshwater lake near the equator? Obviously, you don't want to miss...

They could potentially send a few test attempts with cargo-only or non-NASA missions to test.

> since NASA killed the propulsive landing for Dragon 2

What was the price of that program module for propulsive landing? $2B or the amount of money wasted on the knucklehead category of Ofo bikeshare app business model?

Cannot it be reused because of the splash or because of the salt? What about splash landing in a natural/artificial lake?

or something non liquid - plastic balls, foam pit etc.

After flying on parachutes it's pretty hard to land on a pre-determined place, and the smaller the place the higher chance of missing it. Falcon-9 first stages have more control authority, and even they sometime miss the landing zone if the wind is particularly unfavorable; but they are unmanned and the stakes are lower, in worst case they just won't land softly. Can't have that with manned capsules, so has to have parachutes, so is subjected to winds...

Interesting point. I fly kitesurf kites, so I know a fair bit about piloting a bit of cloth above my head. I'd guess a parachute / kite would be a fun way to land the capsule.

Maybe, and capsule designers considered it. I guess reliability issues dictated dead simple solutions, which lack in landing precision but excel in ensuring survivability?

At the post-launch press conference [1], Musk was asked a question whether they intend to use the capsule for tourism if there were interested individuals. His answer was affirmative, but not for the very near future. Also, it seemed as if they don't intend to go down that path for the general public, but rather have that capability ready for interested people willin to pay a premium.

[1] https://youtu.be/HuXPLtJXd14

Incidentally why does NASA prefer splashing down in the water, rather than a soft landing in dry land like the Russians do?

The plan had been for landing legs with shock absorbers to come out through the heat shield and NASA saw that, understandably, as too big a risk.

Boeing starliner will do a land based return.

Different capsule, different costs and development.

Dragon 2/ Crew Dragon originally was going to support propulsive landing, but nixed due to future architectural plans (making some of Dragon a bit of engineering dead-end versus Starship/ BFR) and complexities in certifying for NASA use.

The Soyuz fires retro-rockets just before landing in Kazakhstan to lessen the impact. Even with that, the landing is still pretty rough. Land landings are sometimes described as akin to a car crash - water landings are softer. I'm sure there's probably a contingency capability of being able to support a land landing for Crew Dragon in case of aborts.

Interesting history note: there was an actually a concern during some of the early Apollo flights (I'm specifically thinking of Apollo 7) of land landings during an abort. Apollo 7 used a Block II version of the Command Module, however the crew couches were still the Block I variant. There was evidence showing the couches wouldn't perform well during a land landing. The concern was that if the LES was used, winds could force the capsule to a land landing. The resolution was that wind speed was a factor in a GO decision for launch.

It's interesting to note that Starliner is planned to perform land landings (using airbags). Land landings for capsules have been worked on since the 60s with the Gemini initially having plans for a Rogallo wing (https://en.wikipedia.org/wiki/Rogallo_wing#/media/File:Gemin...). There were even plans for re-use of the Gemini capsule! Water landings quickly ended that discussion, since salt water is pretty terrible and corrosive.

Water landings have their peculiar risks also, I think there was some incident in Mercury program when Gus Grissom's craft got flooded after splashdown.

SpaceX is breaking new ground, but it isn't the first corporation to launch large rockets. The Saturn 5 wasn't built by the air force, nor was shuttle constructed by Nasa. These objects were built by contractors, corporations working under government contracts. The differences between SpaceX today and the corporations that built, and largely launched, the big rockets of the past is largely a legal distinction.

Space launch is also heavily regulated. SpaceX isn't free to launch anything. Every launch is subject to tight government controls on everything from the technology involved to the specifics of the range. Nobody is going up without US government permission. Their ability to "do" space tourism is not that different than previous space tourists on other rockets. That a corporation is selling the seats, and the passenger lists then being vetted by a government, rather than a national government doing both is again only a legal distinction.+

What other US-based company has had a man-rated rocket such that they owned the full stack, launch facility, etc?

Sure contractors have been involved and built lots of components, but this is the first time a corporation has owned the fully, complete product as well as the facilities to launch and recover.

>What other US-based company has had a man-rated rocket such that they owned the full stack, launch facility, etc?

No company does (including SpaceX)

This is in the context of the OP saying SpaceX will soon also own and operate their own launch facility, so that comment was contrasting the situation SpaceX will be in then to other companies. So I’m afraid your comment kind of misses the point.

Last I heard, SpaceX won't be using Boca Chica for Falcon 9/Heavy launches. So they do have their own launch facility, and they do have their own rockets, but they don't currently have any rockets that they can launch from their LF (which isn't ready yet)

Spacex lease LC39 and LC40 at Cape Canaveral. They are exclusively used for Spacex's launches. SpaceX need approval for launches obviously, but they have full control of the cadence and timetable. NASA and US Air Force are just customers (albeit with higher priority).

They don't own the land like they do with Boca Chica, but from the operational perspective they are the same.

That's not quite how things are in practice. At the Cape and Vandenberg they need to submit a scheduling request to the range. In the past, the Air Force wouldn't allow launches within 72 hours of each other. This caused some conflicts as SpaceX (and to a lesser extent ULA and Orbital/Northrop) upped their launch cadence over the last year. In theory with the Falcon's automated FTS they can launch more frequently than that, but I don't think that has actually happened.

Leasing the pad also prevents SpaceX from making certain modifications and puts some infrastructure constraints on them

The big rockets of the past were in very large part designed by NASA. The contractors did have a lot of input, but NASA drew up the detailed specifications and had the final say on every aspect of the design and engineering. Different components often had different manufacturers. For example each of the three stages of the Saturn 5 had a different manufacturer and all three were designed by NASA. The first stage was built by Boeing, but the F1 engines on it were made by Rocketdyne, all to NASA specs.

In contrast every aspect of the Falcon rocket and Dragon capsule design was determined by SpaceX. NASA set the overall goals and safety criteria, but you can see from the differences between the Starliner and Dragon designs how much scope the manufacturers had. It really is a completely different paradigm.

> It really is a completely different paradigm

It has been done before; for example the Thor IRBM was a competitive bid between Douglas, Lockheed and NAA. Official specs specified the equipment to be carried but the bidders designed their own airframes and launch facilities.

From Wikipedia: The Rocketdyne division of North American Aviation was awarded the engine contract, AC Spark Plug the primary inertial guidance system, Bell Labs the backup radio guidance system, and General Electric the nose cone/reentry vehicle.

Douglas only won the contract to do the airframe and integration. It looks like a typical arrangement of the era. It’s not as if competitive bids have never been part of this process, they very often have. That’s not the point at all.

Final specs on paper came from nasa, but only after much back and forth with industry. The fact that any engineer is paid by nasa or a private company is, as i stated, a simple legal distinction rather than a revolution.

Why would they do day trips when they plan to do suborbital passenger trips. Not make going into space a bucket list item for the upper middle class, but a routine A-to-B for business class flyers.

The bucket list item would be Mars.

I would assume free cash flow would be the reason. Let's assume that you could get $20M per seat on a 7 seat dragon with 2 of those seats going to crew and the other 5 going to paying passengers. You, launch them on a re-usable F9 which you currently charge $80M for a non-reusable booster flight into low orbit. Could you clear 25 - 35 million in margin on that? Could you do that for doing "nothing" special other than having the gear ready? Clearly we'd need way more visibility into their operational costs but if you could generate 250 - 300M$ per year that was not from fixed price contracts I think that would be a helpful thing from a money management perspective.

They still might not do it, but I don't think the sub-orbital passenger trips are very close. So many "other people" have to get involved before that is real, like treaties with the world about how you regulate overflights, or tariffs, or do air traffic control, or who pays when your rocket augurs into the innocent village, Etc. There are lots of details there, whereas Roscosmos has already done tourist flights to the ISS, and with their own launch facilities most of the variables would be under SpaceX's ability to control.

You wouldn't use Dragon, you'd use BFR/Starship: https://www.youtube.com/watch?v=zqE-ultsWt0

> 2 of those seats going to crew

Why exactly do you need crew taking up nearly 30% of the seats on a vessel that can provably operate without them?

Keep order, etc.

SpaceX actually showed a mock-up of what point-to-point travel might look like in one of their videos.

Here: https://www.youtube.com/watch?v=zqE-ultsWt0

The vomit-comet ICBM video? I'm a big fan of SpaceX, but I think they'll get to Mars before governments on Earth allow that concept to happen.

Your passengers do multiple g's to altitude, then go weightless, then go back to taking g-forces on descent. That's the vomit part. Not a great customer experience.

Meanwhile, the Starship looks like an ICBM to every early warning radar on the planet. It's only during reentry that it stops looking like an ICBM, but most missile defense strategies call for intervention in the boost phase.

Let's suppose that they address those false positive detection issues. If you're a military planner, though, you're probably asking yourself how many MIRV warheads could fit inside a militarized Starship retrofitted for a preemptive strike?

Ok, I did some rough math. The W88 has a diameter of 55cm, a length of 175cm, and a blast yield of 475 kilotons. The unpressurized cargo hold of the Starship per Wikipedia is 88m^3, and the diameter of the vehicle is 9m. Let's assume that the unpressurized cargo hold is a cylinder 9m in diameter with a length of 9m.

It looks like a hold of that size could fit 15 units per 200cm length, or 60 units, with space for structural rails and deployment gear. For comparison, that's 7.5x the capacity of the Trident II SLBM which was designed to accommodate 8 W88s.

In terms of potential, one W88 detonated in an airburst would produce a fireball over 1.56 sq km, an air blast to 5psi overpressure over 91.9 sq km, and 3rd degree burns over 233 sq km.

The scale of the human tragedy involved in a first-strike deployment of 60 of these things is too gruesome to write down here, but you can play with it on NukeMap [1] if you're so inclined. Suffice it to say that no sane government on the planet will want Starship to land anywhere nearby unless we're living in a global utopia where this sort of thing is unthinkable.

[1] https://nuclearsecrecy.com/nukemap/

Or they have ability to strike back no matter what.

Maybe, but if governments of the world decide to treat every Starship launch as a potential ICBM, wouldn't it be cheaper and easier to just deny landing rights entirely?

A sky full of friendly traffic makes the hostile traffic more difficult to spot, after all.

Isn't the same math applicable to a jumbo jet? Or a container ship?

Certainly, but neither a jumbo jet nor a container ship has a 30 minute delivery time, and presumably that many warheads has a significant radiation signature.

Let's also not forget about the climate impact of turning rockets into business class travel. It's pretty ridiculous. If we want any change and chance for this planet we should squash initiatives like this in the butt.

Fuel them with Hydrogen/Oxygen produced from electrolysis with solar power.

Or with methane synthesized from CO2 taken from air. You're going to always have CO2 in air, plants need that, so a healthy loop of using it as an energy storage may eventually make sense, today's climate crisis notwithstanding.

> I would like to reiterate the point made before which is that SpaceX is on the verge of being in a place that no company has ever been before with regard to space.

Excuse my ignorance, but what have they done that's so revolutionary? We have been putting people into LEO for decades. What's so groundbreaking about this test?

What’s special isn’t so much putting people into LEO, so much as a private company having done it! It’s one thing for a nation-state to send a mission across the Atlantic or to the moon, but it’s a VERY different thing for companies to begin doing those things — developing rockets has always been enormously expensive, and this test (among others) signals that companies are finding ways to do it profitably. If this trend continues, we can probably expect the cost of a ticket to space to drop dramatically in the next 20 years. Wouldn’t it be amazing to visit other planets in our lifetimes?

I think you are getting ahead of yourselves. For one thing, SpaceX is a launch provider. Whether there is even demand for Mars launches remains to be seen. I think SpaceX itself has said that it can't/won't be funding the Mars launches.

And secondly, this was an unmanned test launch to LEO. I think it'd be more prudent to wait till we get reliable manned launches to LEO before dreaming about other planets.

It's very cool that private companies are now doing this type of stuff. But imo the technical challenges still remain.

> I think SpaceX itself has said that it can't/won't be funding the Mars launches.

What they said was they couldn't be funding the whole Mar endeavor. They certainly can and plan to fund Mars launches. They stated their aspirational goal of sending the first unmanned spaceship to Mar in 2022, followed 2 years later with a manned one. They have seemed to pivot a bit to Moon, so I'm not so sure what their current plan is, but a trip to Mar isn't out of their reach financially.

> but a trip to Mar isn't out of their reach financially.

Source? I highly doubt this is accurate.

The first time I saw this I found it revolutionary and was amazed: https://www.youtube.com/watch?v=1B6oiLNyKKI

I wonder at which point we will start worrying about the carbon footprint of these launches, though. I didn't do the math, but it seems it might become a global factor once you get to multiple launches per week.

https://www.smithsonianmag.com/science-nature/spacex-environ... says:

> if the SpaceX’s plan for a rocket launch every two weeks comes to fruition, this amount of carbon (approximately 4,000 tonnes per year) will rapidly become a bigger problem

So, that gives us a number... and it's also very weird for the Smithsonian to describe that as a "problem". 4,000 tonnes per year is about a thousand cars worth per the EPA's numbers (https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-t...) - pretty much a drop in the bucket.

Rockets and the rocket fuel are also in the "easy to substitute" category. They'll never not be hydrocarbons, but significant work has been done on producing rocket-compatible fuels from biological sources, and the marginal increase in cost if you scaled up to industrial production is possibly going to be entirely unnoticeable considering the general purity and refining requirements of anything you load into a spacecraft.

This, similarly, is also the answer when it comes to aviation by and large. The real problems on Earth are ground transportation and electricity.

How do the biological propellants compare in terms of stability? Maybe not an issue for launches, but I'm curious about their viability in satellite thrusters that hang out for years/decades (although this is a digression from the GRG emission concern)

Satellite thrusters generally use stable hypergolics, to avoid the need for an ignition system, or electric systems such as ion or Hall thrusters.

Hydrogen as the only fuel was in the X-33 project, which technically had a lot of success (before finally closing).

Not even close. A Falcon 9 has no more fuel than a 777. A few 777s per week is inconsequential in a world where there are 100,000 flights per day. Aviation is responsible for only about 3.5% of anthropogenic emissions per year. So even multiple flights per week are just a rounding error on a rounding error.

World CO2 emissions last year was ~ 37Gigatons of carbon. A F9 launch uses of order 100 tons of RP1, so global emissions correspond to about 370 million launches...

Note that 1 ton of fuel yields more than 1 ton of CO₂: https://www.fueleconomy.gov/feg/contentIncludes/co2_inc.htm

(Though it's still comparable in "order of magnitude" terms.)

Here’s some numbers I looked up:

Average co2 from a car per year: 4.6 metric tons (https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-t...)

co2 output from a Falcon 9 launch: 440,000kg or 440 metric tons (https://space.stackexchange.com/questions/13082/calculate-fa...)

So a single launch is about 95 cars worth of exhaust a year, give or take.

There were 21 SpaceX launches last year (https://en.m.wikipedia.org/wiki/List_of_Falcon_9_and_Falcon_...)

The number of launches is expect to increase to 30-40 a year (previous source).

Let’s go with 35 launches per year. And remember we’re disregarding all other rockets launches in the world.

35 x 95 = 3325 cars worth of emissions per year.

It’s definitely not great. However it’s such a tiny drop in the bucket overall that it’s not even a rounding error. I think cows produce more methane per year. I’m on mobile at the moment so not gonna look up those numbers.

Rockets get terrible gas mileage.

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