SpaceX CCtCAP Milestones

[rds100]

Why splashdown at sea and deal with salt water? Why not splashdown in an artificial lake or even in a pool?

[guckyfan]

Why splashdown at sea and deal with salt water? Why not splashdown in an artificial lake or even in a pool?

Much better still, do powered landings on land. Initially parachutes with engine assist. then fully powered landing. NASA should have a few missions where there is no highly valuable downmass.

[rds100]

Yes, but landing on a firm land will probably require some sort of legs, which we haven't seen yet. Although the Soyuz doesn't have any legs, so obviously there is a way.
On the other hand a powered splashdown in a pool could be done without legs.

[IainMcClatchie]

They are pretty accurate at landing that first stage, and the capsule should have even better lift and so more manoeverability.  Maybe they can land it on a crushable bed with no legs.

They'll want legs for Mars, so they're going that way anyway.  And they've shown mock-ups of the capsule with legs.

[docmordrid]

Yes, but landing on a firm land will probably require some sort of legs, which we haven't seen yet.
>

They've probably evolved since, but the legs were photographed by Helodriver(?) at the Dragon v2 introduction and they've changed little in SpaceX artwork since. Maybe a tad longer.

[dglow]

I don't think we know the Falcon Heavy demo flight's payload... if Dragon 2, the demo could a dress rehearsal for Mars 2018 and a propulsive landing test.

The FH Demo is effectively a 'free' flight. Won't NASA mandate parachutes+water landings for all Commercial Crew flights through 2018 (at least)?

[starsilk]

Regarding this tweet:
https://twitter.com/elonmusk/status/726217758229168129

you going to test dragon 2 propulsive landing from earth orbit before Mars attempt ?

@elonmusk: yes, several times

Any insight on whether this can be done with the uncrewed test flight? I.e., will it involve cargo return which would preclude testing?
And would the large volume of hydrazine be permitted at ISS?

Otherwise these "several" tests would be cost prohibitive except with reused cores and Dragons. (but that is for another thread)

(my emphasis)
The "large volume of hydrazine" HAS TO "be permitted at ISS" because every mission that gets to the ISS will, by definition, not have aborted, and the fuel for the abort will still be on board Dragon 2.  That's the "magic" of powered landings.  The fuel is loaded in any case.  The only "cost" is carrying it from the upper limit of the abort range to orbit.

not true.. NASA *could* insist the majority of it is burned off before approaching the ISS, as a 'third stage'.

doing so would of course mean that Dragon would have to do a parachute landing, which is going to be the case for the first few flights anyway.

[llanitedave]

Regarding this tweet:
https://twitter.com/elonmusk/status/726217758229168129

you going to test dragon 2 propulsive landing from earth orbit before Mars attempt ?

@elonmusk: yes, several times

Any insight on whether this can be done with the uncrewed test flight? I.e., will it involve cargo return which would preclude testing?
And would the large volume of hydrazine be permitted at ISS?

Otherwise these "several" tests would be cost prohibitive except with reused cores and Dragons. (but that is for another thread)

(my emphasis)
The "large volume of hydrazine" HAS TO "be permitted at ISS" because every mission that gets to the ISS will, by definition, not have aborted, and the fuel for the abort will still be on board Dragon 2.  That's the "magic" of powered landings.  The fuel is loaded in any case.  The only "cost" is carrying it from the upper limit of the abort range to orbit.

not true.. NASA *could* insist the majority of it is burned off before approaching the ISS, as a 'third stage'.

doing so would of course mean that Dragon would have to do a parachute landing, which is going to be the case for the first few flights anyway.

And NASA *could* insist that all future astronauts to the ISS wear blue face paint and shave their heads.  But there's no reason to expect they *would* do such a thing.  Why do you expect them to suddenly panic at the thought of hydrazine?

[starsilk]

Regarding this tweet:
https://twitter.com/elonmusk/status/726217758229168129

you going to test dragon 2 propulsive landing from earth orbit before Mars attempt ?

@elonmusk: yes, several times

Any insight on whether this can be done with the uncrewed test flight? I.e., will it involve cargo return which would preclude testing?
And would the large volume of hydrazine be permitted at ISS?

Otherwise these "several" tests would be cost prohibitive except with reused cores and Dragons. (but that is for another thread)

(my emphasis)
The "large volume of hydrazine" HAS TO "be permitted at ISS" because every mission that gets to the ISS will, by definition, not have aborted, and the fuel for the abort will still be on board Dragon 2.  That's the "magic" of powered landings.  The fuel is loaded in any case.  The only "cost" is carrying it from the upper limit of the abort range to orbit.

not true.. NASA *could* insist the majority of it is burned off before approaching the ISS, as a 'third stage'.

doing so would of course mean that Dragon would have to do a parachute landing, which is going to be the case for the first few flights anyway.

And NASA *could* insist that all future astronauts to the ISS wear blue face paint and shave their heads.  But there's no reason to expect they *would* do such a thing.  Why do you expect them to suddenly panic at the thought of hydrazine?

I didn't say I expected them to do that. I was just pointing out the fallacy of Comga's argument that NASA 'HAS TO' accept it. no they don't.

[abaddon]

I didn't say I expected them to do that. I was just pointing out the fallacy of Comga's argument that NASA 'HAS TO' accept it. no they don't.

It's more accurate to say NASA has accepted it... because they have.  To argue "has to" versus "has" seems a bit pedantic to me.

[BrianNH]

Musk could have been thinking about high altitude drops from a helicopter.  The intent being to test the propulsive landing rather than the TPS system.  Much more cost effective than a launch.  Still, Mars' thinner atmosphere can't realistically be replicated on Earth.

[AS-503]

With regard to the large-ish amount of hydrazine on board the Dragon 2 capsule being permitted at the ISS....
What about the equally large or larger amount of hydrazine in the Shuttles' OMS pods and RCS system?
Hasn't that presumably large quantity of hydrazine already been at the ISS on every Shuttle mission?

[JamesH65]

Musk could have been thinking about high altitude drops from a helicopter.  The intent being to test the propulsive landing rather than the TPS system.  Much more cost effective than a launch.  Still, Mars' thinner atmosphere can't realistically be replicated on Earth.

Is a Dragon small enough to drop out the back of a C17 GlobemasterIII ? I suspect so since they can carry battletanks.

That might be a cheap option for test from higher altitudes than a helicopter. If they can borrow/hire one more cheaply than using a reused F9.

[dglow]

Musk could have been thinking about high altitude drops from a helicopter.  The intent being to test the propulsive landing rather than the TPS system.  Much more cost effective than a launch.  Still, Mars' thinner atmosphere can't realistically be replicated on Earth.

There is a thin portion of Earth's upper atmosphere which mimics that of Mars. The HIAD team makes use of this when testing their design, which is intended for Mars EDL.

[enzo]

Alright I started this so I will try to conclude it. Question answered—yes, it is feasible to bring the Dragon 2 back down from ISS to propulsive landing test, and the downmass cargo is not likely to be an issue, but if it is then water landing may appease the faint of heart.
(As for parachutes, of course they will use parachutes at first for crew return, but I was talking about the uncrewed test.)

[dglow]

(As for parachutes, of course they will use parachutes at first for crew return, but I was talking about the uncrewed test.)

Understood, however: if that 'uncrewed test' is part of the Commercial Crew program then it's more than likely that NASA will demand a non-propulsive water landing.

This is how the first crews will land... test like you fly.

[enzo]

(As for parachutes, of course they will use parachutes at first for crew return, but I was talking about the uncrewed test.)

Understood, however: if that 'uncrewed test' is part of the Commercial Crew program then it's more than likely that NASA will demand a non-propulsive water landing.

This is how the first crews will land... test like you fly.

Not disputing your logic, but there is a parachute drop test(s) prior to crew.
But the more parachute tests the better, you say.
Sure, so why not do this: multiple parachute-only drop tests, and one SuperDraco-only landing test (uncrewed ISS mission) prior to crew return — this enables redundancy for landing, whereas testing only parachute-dependent landings (albeit one using SuperDraco "padded" landing) leaves no redundancy for the crew.

[joek]

Progression expected:
1. Parachutes on water -- stated as the baseline.
2. Parachutes + propulsive on water  (conjecture) -- to prove propulsive terminal capabilities.
3. Parachutes + propulsive on ground -- probably for cargo.
4. Propulsive on ground -- possibly for cargo; possibly never for crew.
Cargo would lead crew.
Remember we are talking about CCtCap here (crew), not cargo.

[joek]

With regard to the large-ish amount of hydrazine on board the Dragon 2 capsule being permitted at the ISS....
What about the equally large or larger amount of hydrazine in the Shuttles' OMS pods and RCS system?
Hasn't that presumably large quantity of hydrazine already been at the ISS on every Shuttle mission?

Correct that quantities of hyperbolics should not be an issue.  Boeing also as a similar issue, and has also mumbled about CST-100's potential ability to help with ISS reboost--although they seem to have gone mum on that subject.

[guckyfan]

[quote author=AS-503 link=topic=39832.msg1564072#msg1564072
Correct that quantities of hyperbolics should not be an issue.  Boeing also as a similar issue, and has also mumbled about CST-100's potential ability to help with ISS reboost--although they seem to have gone mum on that subject.

There has always been a lot of hyperbole around the Shuttle. 

I do wonder about reboost. It has been said that the ports are in the wrong position. But the Shuttle did reboosts, right? The Shuttle docking port is one of the ports for CC vehicles so why not? Is it about reorientation of the ISS?