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While the tried and true method of splashing down in the ocean seems like a reasonable first effort for landing the dragon spacecraft, watching the difficulty t

While the tried and true method of splashing down in the ocean seems like a reasonable first effort for landing the dragon spacecraft, watching the difficulty the boats have in reaching the spacecraft (the hosts of the stream mentioned it takes them 2 hours!), and the difficulty the SpaceX team had in getting reasonable weather conditions for this test, it seems to me that a propulsive land-based landing would still be a reasonable future improvement to pursue.

davedx 7y ago
If you were the astronaut and it was an emergency that triggered the abort (e.g. the launch vehicle blew up like the Falcon 9 just did), would you really prefer the Dragon tried to land instead of at sea? Keep in mind it wouldn't be able to choose its landing site either.
- whoisthemachine 7y ago
  As I replied elsewhere, for an abort, a water landing definitely makes sense (and is likely the only reasonable option). I was merely commenting on how drawn out the recovery process is after splashdown, which I would assume would be less time-consuming with a land landing.
mechhacker 7y ago
That would require significantly more fuel and a different design, likely limiting the Dragon's crew payload. This abort happened after the rocket reached max Q (highest dynamic pressure) when it was flying East (and still upward, but to get to orbit you must fly sideways over water). Returning West to get back over land would be fuel prohibitive on a fully loaded crew capsule. The reusable falcon 9 stages have almost nothing in them when they fly back to land. See trajectories: https://i.redd.it/xaisqxao5ef01.png https://i.redd.it/xaisqxao5ef01.png
- whoisthemachine 7y ago
  For an abort, a water landing definitely makes sense. Perhaps there is no way to avoid the tough weather requirements for the downrange abort. The lengthy recovery time still seems due to the water landing, however. I wonder if it will be a 2 hour recovery time during normal water landing?
  - whoisthemachine 7y ago
    I still wonder how much more difficult it is to get proper weather conditions over open sea vs. land when preparing to land during a normal flight. I'd imagine strong winds become stronger over sea than over land, and of course, the ability for ships to reach you in choppy seas becomes much more difficult.
shkkmo 7y ago
That was the original end plan, but AFAIK it was mixed a couple of years ago. “The reason we decided not to pursue (powered landings) heavily is it would have taken a tremendous amount of effort to qualify that for safety, particularly for crew transport,” Musk said. “And then there was a time when I thought that the Dragon approach to landing on Mars, where you’ve got a base heat shield and side-mounted thrusters, would be the right way to land on Mars, but now I’m pretty confident that is not the right way, and that there’s a far better approach.” [0] [0] https://spaceflightnow.com/2017/07/19/propulsive-landings-nixed-from-spacexs-dragon-spaceship/ https://spaceflightnow.com/2017/07/19/propulsive-landings-ni...
- lutorm 7y ago
  To be clear, propulsively landing after an abort was never planned -- you've already used up the fuel doing the abort. Plus, depending on when you abort, you could be half-way across the Atlantic.
  - mechhacker 7y ago
    Do you know if they had a path for redundancy for a propulsive abort? With 4 parachutes, they likely have the design able to handle a single 'chute failure. Not sure what would be involved with single failures on the propulsive abort but that may have been a large contributor to go with the required return fuel.
    - greglindahl 7y ago
      The propulsion is pairs of engines for redundancy, but, as people keep on saying, abort was always going to be parachutes.
    - lutorm 7y ago
      The abort is the redundancy... ;-) I'm not sure what specifically you are thinking about, but in general since an abort is already one critical fault away from the nominal case, I believe the requirements for redundancy are lower.
fit2rule 7y ago
I think you misunderstood the announcer - the recovery takes 2 hours, but that's not how long it takes the boats to get to the capsule at its splashdown location. The boats get there pretty quickly. The time required is for safety checks and so on - there's some pretty nasty materials involved in those thruster engines, and all that stuff has to be checked first.
- whoisthemachine 7y ago
  Interesting, so given this do you think that a normal landing would not have as long of a recovery time, given that it won't use those thruster engines?
  - greglindahl 7y ago
    For a normal landing, there’s an extra step of hoisting the entire capsule onto the ship before opening the hatch.
- skunkworker 7y ago
  In addition to this. The Air Force has personnel that can jump out of the plane with flotation, medical equipment and food in order to survive for an extended period of time on the ocean while it may take a few hours to get fast boats and recovery teams there.
C14L 7y ago
NASA didn't require it. There was an early plan at SpaceX to have Crew Dragon land propulsivly, but they didn't pursue it in favor of developing Starship and SuperHeavy faster. That's what Musk said in an interview some time ago.
- whoisthemachine 7y ago
  I remember that. It still seems to make sense to research propulsive landings and gain NASA's approval for them eventually (while maintaining the well-proven water landing capability) if it would cut costs significantly.
  - greglindahl 7y ago
    Losing science return cargo from a landing failure during testing is a no-no.
  - C14L 7y ago
    From what I remember, after Dragon2 is approved by NASA, all development efforts of SpaceX will be focused on Starship and Super Heavy only. Dragon2 is no use in the efforts to build a city on Mars. And even for a Moon colony, its too small. Its just there to earn money from flying people to the ISS and back. And for that its already good enough.
jessriedel 7y ago
Boeing's Starliner lands on solid ground after a normal mission while SpaceX's Dragon lands in the ocean. But that's not relevant to an in-flight abort. Any abort at this stage in the launch (whether Boeing or SpaceX) has to come down over water. That's simply where the trajectory of the launch goes.
- whoisthemachine 7y ago
  As I replied elsewhere, for an abort, a water landing definitely makes sense (and is likely the only reasonable option). I was merely commenting on how drawn out the recovery process is after splashdown, which I would assume would be less time-consuming with a land landing.
  - Fronzie 7y ago
    In the introduction of the space-x launch broadcast, they mention that in real aborts, military will be involved. With helicopters, rescue personnel will be dropped of. Also there, it still takes a while for boats to arrive.
  - brianwawok 7y ago
    Your odds of hitting something hard are much higher on land. Or smooshing someone.
- Already__Taken 7y ago
  Was crew dragons plan back with normal propulsive landings to always fly back to ground and just load more fuel?
_ph_ 7y ago
My understanding is, that the Nasa didn't like the idea of propulsive landing. As the dragon capsule is purely for supporting the ISS, SpaceX has no incentive to spend money on anything they are not using for the Nasa missions. For everything else, they are developing the Starship. If that program goes as planned, the dragon capsule will be used only for a short time, I guess.
- iso1824 7y ago
  > If that program goes as planned, the dragon capsule will be used only for a short time, I guess. I can't see Starship being approved for Nasa use by 2024 even if it were flying today.
  - JshWright 7y ago
    Why not? It didn't take that long to certify Dragon, and most of the delays were on SpaceX (like blowing up the capsule they were originally intending to use for this test).
  - Klathmon 7y ago
    I believe SpaceX isn't working with NASA to get Starship human rated by them. I think they are trying to do it 100% private, partially so they don't need to prove it to NASA's standards.
grey-area 7y ago
it seems to me that a propulsive land-based landing would still be a reasonable future improvement to pursue. They're working on a second stage that can carry a few more astronauts and land itself, it's a bit bigger though ;) https://www.spacex.com/starship https://www.spacex.com/starship
- whoisthemachine 7y ago
  Yes, I'm well aware of that! Hopefully, they get that flying so soon that pursuing more advanced landing methods for the dragon is not needed :)
whoisthemachine 7y ago
Interestingly, in the press conference, Musk mentioned that SpaceX would like to try to catch spacecraft, which I would think would reduce some of the water landing costs.
busymom0 7y ago
> watching the difficulty the boats have in reaching the spacecraft (the hosts of the stream mentioned it takes them 2 hours!) From my understanding, the host meant that getting the dragon and crew back to the shore would take 2 hours, not the recovery boat to get to them. They could probably even have helicopters around the area which could fly and pick the dragon up.

davedx 7y ago

If you were the astronaut and it was an emergency that triggered the abort (e.g. the launch vehicle blew up like the Falcon 9 just did), would you really prefer the Dragon tried to land instead of at sea? Keep in mind it wouldn't be able to choose its landing site either.

whoisthemachine 7y ago
As I replied elsewhere, for an abort, a water landing definitely makes sense (and is likely the only reasonable option). I was merely commenting on how drawn out the recovery process is after splashdown, which I would assume would be less time-consuming with a land landing.

mechhacker 7y ago

That would require significantly more fuel and a different design, likely limiting the Dragon's crew payload. This abort happened after the rocket reached max Q (highest dynamic pressure) when it was flying East (and still upward, but to get to orbit you must fly sideways over water). Returning West to get back over land would be fuel prohibitive on a fully loaded crew capsule. The reusable falcon 9 stages have almost nothing in them when they fly back to land. See trajectories: https://i.redd.it/xaisqxao5ef01.png https://i.redd.it/xaisqxao5ef01.png

whoisthemachine 7y ago
For an abort, a water landing definitely makes sense. Perhaps there is no way to avoid the tough weather requirements for the downrange abort. The lengthy recovery time still seems due to the water landing, however. I wonder if it will be a 2 hour recovery time during normal water landing?
- whoisthemachine 7y ago
  I still wonder how much more difficult it is to get proper weather conditions over open sea vs. land when preparing to land during a normal flight. I'd imagine strong winds become stronger over sea than over land, and of course, the ability for ships to reach you in choppy seas becomes much more difficult.

shkkmo 7y ago

That was the original end plan, but AFAIK it was mixed a couple of years ago. “The reason we decided not to pursue (powered landings) heavily is it would have taken a tremendous amount of effort to qualify that for safety, particularly for crew transport,” Musk said. “And then there was a time when I thought that the Dragon approach to landing on Mars, where you’ve got a base heat shield and side-mounted thrusters, would be the right way to land on Mars, but now I’m pretty confident that is not the right way, and that there’s a far better approach.” [0] [0] https://spaceflightnow.com/2017/07/19/propulsive-landings-nixed-from-spacexs-dragon-spaceship/ https://spaceflightnow.com/2017/07/19/propulsive-landings-ni...

lutorm 7y ago
To be clear, propulsively landing after an abort was never planned -- you've already used up the fuel doing the abort. Plus, depending on when you abort, you could be half-way across the Atlantic.
- mechhacker 7y ago
  Do you know if they had a path for redundancy for a propulsive abort? With 4 parachutes, they likely have the design able to handle a single 'chute failure. Not sure what would be involved with single failures on the propulsive abort but that may have been a large contributor to go with the required return fuel.
  - greglindahl 7y ago
    The propulsion is pairs of engines for redundancy, but, as people keep on saying, abort was always going to be parachutes.
  - lutorm 7y ago
    The abort is the redundancy... ;-) I'm not sure what specifically you are thinking about, but in general since an abort is already one critical fault away from the nominal case, I believe the requirements for redundancy are lower.

fit2rule 7y ago

I think you misunderstood the announcer - the recovery takes 2 hours, but that's not how long it takes the boats to get to the capsule at its splashdown location. The boats get there pretty quickly. The time required is for safety checks and so on - there's some pretty nasty materials involved in those thruster engines, and all that stuff has to be checked first.

whoisthemachine 7y ago
Interesting, so given this do you think that a normal landing would not have as long of a recovery time, given that it won't use those thruster engines?
- greglindahl 7y ago
  For a normal landing, there’s an extra step of hoisting the entire capsule onto the ship before opening the hatch.
skunkworker 7y ago
In addition to this. The Air Force has personnel that can jump out of the plane with flotation, medical equipment and food in order to survive for an extended period of time on the ocean while it may take a few hours to get fast boats and recovery teams there.

C14L 7y ago

NASA didn't require it. There was an early plan at SpaceX to have Crew Dragon land propulsivly, but they didn't pursue it in favor of developing Starship and SuperHeavy faster. That's what Musk said in an interview some time ago.

whoisthemachine 7y ago
I remember that. It still seems to make sense to research propulsive landings and gain NASA's approval for them eventually (while maintaining the well-proven water landing capability) if it would cut costs significantly.
- greglindahl 7y ago
  Losing science return cargo from a landing failure during testing is a no-no.
- C14L 7y ago
  From what I remember, after Dragon2 is approved by NASA, all development efforts of SpaceX will be focused on Starship and Super Heavy only. Dragon2 is no use in the efforts to build a city on Mars. And even for a Moon colony, its too small. Its just there to earn money from flying people to the ISS and back. And for that its already good enough.

jessriedel 7y ago

Boeing's Starliner lands on solid ground after a normal mission while SpaceX's Dragon lands in the ocean. But that's not relevant to an in-flight abort. Any abort at this stage in the launch (whether Boeing or SpaceX) has to come down over water. That's simply where the trajectory of the launch goes.

whoisthemachine 7y ago
As I replied elsewhere, for an abort, a water landing definitely makes sense (and is likely the only reasonable option). I was merely commenting on how drawn out the recovery process is after splashdown, which I would assume would be less time-consuming with a land landing.
- Fronzie 7y ago
  In the introduction of the space-x launch broadcast, they mention that in real aborts, military will be involved. With helicopters, rescue personnel will be dropped of. Also there, it still takes a while for boats to arrive.
- brianwawok 7y ago
  Your odds of hitting something hard are much higher on land. Or smooshing someone.
Already__Taken 7y ago
Was crew dragons plan back with normal propulsive landings to always fly back to ground and just load more fuel?

_ph_ 7y ago

My understanding is, that the Nasa didn't like the idea of propulsive landing. As the dragon capsule is purely for supporting the ISS, SpaceX has no incentive to spend money on anything they are not using for the Nasa missions. For everything else, they are developing the Starship. If that program goes as planned, the dragon capsule will be used only for a short time, I guess.

iso1824 7y ago
> If that program goes as planned, the dragon capsule will be used only for a short time, I guess. I can't see Starship being approved for Nasa use by 2024 even if it were flying today.
- JshWright 7y ago
  Why not? It didn't take that long to certify Dragon, and most of the delays were on SpaceX (like blowing up the capsule they were originally intending to use for this test).
- Klathmon 7y ago
  I believe SpaceX isn't working with NASA to get Starship human rated by them. I think they are trying to do it 100% private, partially so they don't need to prove it to NASA's standards.

grey-area 7y ago

it seems to me that a propulsive land-based landing would still be a reasonable future improvement to pursue. They're working on a second stage that can carry a few more astronauts and land itself, it's a bit bigger though ;) https://www.spacex.com/starship https://www.spacex.com/starship

whoisthemachine 7y ago
Yes, I'm well aware of that! Hopefully, they get that flying so soon that pursuing more advanced landing methods for the dragon is not needed :)

whoisthemachine 7y ago

Interestingly, in the press conference, Musk mentioned that SpaceX would like to try to catch spacecraft, which I would think would reduce some of the water landing costs.

busymom0 7y ago

> watching the difficulty the boats have in reaching the spacecraft (the hosts of the stream mentioned it takes them 2 hours!) From my understanding, the host meant that getting the dragon and crew back to the shore would take 2 hours, not the recovery boat to get to them. They could probably even have helicopters around the area which could fly and pick the dragon up.