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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,
by Tuna-Fish 8y ago
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.
- rsj_hn 8y agoThat'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?
- deedubaya 8y agoI'm guessing its the salt water that is the problem.
- huehehue 8y ago"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/20170000606.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...
- varjag 8y agoThis is related to rocket engines, not ballistic descent capsules.
- Teever 8y agoBallistic descent capsules such as the Dragon have rocket engines in them.
- deleted 8y ago[deleted]
- avmich 8y agoTrue. 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.
- based2 8y agojust create a movable water pool for the ocean. http://news.mit.edu/2015/shockwave-process-desalination-water-1112 http://news.mit.edu/2015/shockwave-process-desalination-wate...
- bahmboo 8y agoI live by salt water. Salt water destroys everything. Sometimes quickly but always eventually. Ok, maybe not fish.
- lenocinor 8y agoIt's really true. In your home it'll even happen to your indoor stuff if you're not careful.
- varjag 8y agoCarbon steel hull ships traverse saltwater for many decades however.
- emiliobumachar 8y agoWhat's their maintenance like?
- varjag 8y agoScrub/repaint every few years? In comparison, splashdown capsules spend maybe few hours tops in the water.
- lutorm 8y agoThe problem is that, unlike ships, they're generally not designed to be water proof. It's not the exterior that's the problem.
- luke0016 8y agoI 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?
- politician 8y ago
- ChuckMcM 8y agoI'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.
- perilunar 8y agoI 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.
- simonh 8y agoMr 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.
- influx 8y agoWhy did they force the requirement for saltwater splashdown?
- rhcom2 8y agoIIRC they were concerned about having retractable legs beneath the heat shield so in terms of complexity the water landing is safer.
- valuearb 8y agoNo, 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.
- slg 8y agoI 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?
- phkahler 8y ago+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. ;-)
- torpfactory 8y agohttps://en.wikipedia.org/wiki/Keweenaw_Rocket_Range 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.
- nordsieck 8y ago
- sourkremlin 8y agowhere did you hear that dragon 2 is not safe for humans after splashdown? that's not accurate
- trashaccount123 8y agoCan confirm it’s not accurate.
- alexanderdmitri 8y agothank you for the confirmation trashaccount123
- benatkin 8y agoI 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.
- skellington 8y agoYou know, it's like how once you put a boat into water once, it's unsafe for humans...
- Rapzid 8y agoAny 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.
- jordanthoms 8y agoAs 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.
- kevin_thibedeau 8y agoCargo 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.
- valuearb 8y agoExpense. NASA won’t pay for it and SpaceX is focused on Starship.
- deleted 8y ago[deleted]
- iamcreasy 8y ago> 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.
- rst 8y agoCombined 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.
- mandeepj 8y agoFalcon 9’s landing on land tech can’t be used in dragon?
- avmich 8y agoNo, it's not reliable enough. Energiya considered powered landing for Zarya capsule https://en.wikipedia.org/wiki/Zarya_(spacecraft) https://en.wikipedia.org/wiki/Zarya_(spacecraft) and felt it wasn't safe to land this way.
- oh_sigh 8y agoHow 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...
- gibolt 8y agoThey could potentially send a few test attempts with cargo-only or non-NASA missions to test.
- rockxloose 8y ago> 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?
- antpls 8y agoCannot it be reused because of the splash or because of the salt? What about splash landing in a natural/artificial lake?
- monk_e_boy 8y agoor something non liquid - plastic balls, foam pit etc.
- avmich 8y agoAfter 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...
- monk_e_boy 8y agoInteresting 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.
- avmich 8y agoMaybe, and capsule designers considered it. I guess reliability issues dictated dead simple solutions, which lack in landing precision but excel in ensuring survivability?
- tomiplaz 8y agoAt 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 https://youtu.be/HuXPLtJXd14
- billfruit 8y agoIncidentally why does NASA prefer splashing down in the water, rather than a soft landing in dry land like the Russians do?
- Symmetry 8y agoThe 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.
- vermontdevil 8y agoBoeing starliner will do a land based return. Different capsule, different costs and development.
- amatwl 8y agoDragon 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:Gemini_paraglider.JPG 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.