Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 2  (Read 773667 times)

Offline soltasto

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #580 on: 07/26/2017 01:56 pm »
None for STS but multiple for others. NASA is using double standards.

No, that was more than 35 years ago and NASA learned the error of its ways.  Orion was not manned for its first flight.

My understanding is that since it's a test mission, they just want to test the rocket and see how it performs. Sure, money would have been needed for the ECLSS and other stuff to get humans on it, but the unexpected can't be bought.

Really?  The main reason that NASA is not pushing away at a manned EM-1 right is money. If congress and the administration opened up the check book they would be on that path now.

I agree with woods on this one. Major double standard.

Wrong.  Even with money they would not have done it

I get the impression that the manned EM-1 study was due to pressure from outside NASA, and that NASA was pretty broadly opposed to the idea (hence the ultimate rejection). Is that more or less right, Jim?

Offline notsorandom

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #581 on: 07/26/2017 02:59 pm »
The Shuttle had 5 ALT flights before STS-1. There were many never tried before things done on STS-1 but the landing part was tested beforehand pretty well. There doesn't seem to be a way to test the Dragon's propulsive landing short of an orbital or sub orbital flight on a Falcon. Looks like NASA doesn't want to risk its cargo or crew and SpaceX doesn't want to pay for a number of dedicated test flights to prove it out.

Online abaddon

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #582 on: 07/26/2017 03:30 pm »
There doesn't seem to be a way to test the Dragon's propulsive landing short of an orbital or sub orbital flight on a Falcon.
What?  A drop test would be a fine way to test the landing, easily equivalent to Shuttle ALT flights.

Offline Thorny

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #583 on: 07/26/2017 03:37 pm »
And it too heavy for helicopter drop (plus probably not high enough)

What about out the back of a C-17, like Orion chute tests?

Offline Prettz

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #584 on: 07/26/2017 04:09 pm »
The Shuttle had 5 ALT flights before STS-1. There were many never tried before things done on STS-1 but the landing part was tested beforehand pretty well. There doesn't seem to be a way to test the Dragon's propulsive landing short of an orbital or sub orbital flight on a Falcon. Looks like NASA doesn't want to risk its cargo or crew and SpaceX doesn't want to pay for a number of dedicated test flights to prove it out.
Then why wasn't the cost part of their bid? Or was it.

Offline StuffOfInterest

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #585 on: 07/26/2017 05:31 pm »
Has there been any word of what happened with the tethered Dragonfly testing?  Considering that SpaceX was working on the dynamics of landing under power I wonder if they learned something about control stability that led them to decide it wasn't worth pushing forward.

Offline LooksFlyable

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #586 on: 07/26/2017 05:40 pm »
Suggest the lack of anything beyond water landing is due to mutual lack of interest by NASA and SX, for different reasons.

SX reasons don't need to be remarked upon. NASA's do, but are unacceptable to have a professional discourse on.

I wanted propulsive Dragon, but I never liked the idea of last second hoverslam propulsive landings. It just seems like too much risk when you can have a system of retroburning high above the atmosphere then triple redundant parachutes for landing, and maybe just using propulsion to guide it, or using that as a last resort if parachutes fail. Perhaps using an inflatable heat shield as well. I just know I would want more safety systems on a human rated vehicle. Having said that, for some cargo missions, you can take a chance, so I'm still disappointed that they completely axed it since that will push back the day when we will truly have a fully reusable, easy to refurbish system. They might not even be the first ones to achieve that goal now, depending on how long the new ITS will take to complete.

Offline Space Ghost 1962

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #587 on: 07/26/2017 06:53 pm »
Suggest the lack of anything beyond water landing is due to mutual lack of interest by NASA and SX, for different reasons.

SX reasons don't need to be remarked upon. NASA's do, but are unacceptable to have a professional discourse on.

I wanted propulsive Dragon, but I never liked the idea of last second hoverslam propulsive landings. It just seems like too much risk when you can have a system of retroburning high above the atmosphere then triple redundant parachutes for landing, and maybe just using propulsion to guide it, or using that as a last resort if parachutes fail. Perhaps using an inflatable heat shield as well. I just know I would want more safety systems on a human rated vehicle. Having said that, for some cargo missions, you can take a chance, so I'm still disappointed that they completely axed it since that will push back the day when we will truly have a fully reusable, easy to refurbish system. They might not even be the first ones to achieve that goal now, depending on how long the new ITS will take to complete.

Soyuz has always done partially propulsive "land" landings. No reason Dragon 2 couldn't as well.

Should be professionally discussed w/o childish issues. Really, really annoying.

Offline Jim

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #588 on: 07/26/2017 06:58 pm »
There doesn't seem to be a way to test the Dragon's propulsive landing short of an orbital or sub orbital flight on a Falcon.
What?  A drop test would be a fine way to test the landing, easily equivalent to Shuttle ALT flights.

how are you going to drop a spacecraft with hypergols? It is too heavy for helicopter

Offline Jim

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #589 on: 07/26/2017 08:33 pm »
There doesn't seem to be a way to test the Dragon's propulsive landing short of an orbital or sub orbital flight on a Falcon.
What?  A drop test would be a fine way to test the landing, easily equivalent to Shuttle ALT flights.

how are you going to drop a spacecraft with hypergols? It is too heavy for helicopter
http://www.helipress.net/schede-708-the_top_5_heavy_lift_helicopters_video

Too heavy for number 4 & 5.  Musk is not going to use Russian copters, plus I doubt they are certified in the US.

Offline LooksFlyable

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #590 on: 07/26/2017 08:43 pm »
Suggest the lack of anything beyond water landing is due to mutual lack of interest by NASA and SX, for different reasons.

SX reasons don't need to be remarked upon. NASA's do, but are unacceptable to have a professional discourse on.

I wanted propulsive Dragon, but I never liked the idea of last second hoverslam propulsive landings. It just seems like too much risk when you can have a system of retroburning high above the atmosphere then triple redundant parachutes for landing, and maybe just using propulsion to guide it, or using that as a last resort if parachutes fail. Perhaps using an inflatable heat shield as well. I just know I would want more safety systems on a human rated vehicle. Having said that, for some cargo missions, you can take a chance, so I'm still disappointed that they completely axed it since that will push back the day when we will truly have a fully reusable, easy to refurbish system. They might not even be the first ones to achieve that goal now, depending on how long the new ITS will take to complete.

Soyuz has always done partially propulsive "land" landings. No reason Dragon 2 couldn't as well.

Should be professionally discussed w/o childish issues. Really, really annoying.

I don't think you understood what I said. Soyuz using retro-burns to cushion the landing is actually an example of what I am saying.
« Last Edit: 07/26/2017 08:45 pm by LooksFlyable »

Online yg1968

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #591 on: 07/26/2017 09:05 pm »
People are taking NASA to task and don't know what they are talking about.

Nobody is stepping back and looking at what the issues are.

I don't have inside knowledge about this but it seems easy to figure out.

The issue is qualification of the landing system.  Let me ask how many flights is it taking the Falcon 9 to be qualified as a crew launch vehicle?

And how many flights of a propulsive landing Dragon would be required to qualify it (hover tests don't count)?
Propulsive cargo landings were going to pave the way for propulsive crew landing. However,  NASA said "No" to those as well.

Same issue, how many qual flights.
None for STS but multiple for others. NASA is using double standards.

A demo uncrewed flight wasn't actually required by NASA for CtCap but both providers proposed it.

Offline envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #592 on: 07/26/2017 09:05 pm »
There doesn't seem to be a way to test the Dragon's propulsive landing short of an orbital or sub orbital flight on a Falcon.
What?  A drop test would be a fine way to test the landing, easily equivalent to Shuttle ALT flights.

how are you going to drop a spacecraft with hypergols? It is too heavy for helicopter
http://www.helipress.net/schede-708-the_top_5_heavy_lift_helicopters_video

Too heavy for number 4 & 5.  Musk is not going to use Russian copters, plus I doubt they are certified in the US.

The CH-53E can carry slung loads of up to about 36,000 lb, while the Dragonfly test article was about 14,000 lb.

What's your basis for stating that Dragon would be too heavy for it to lift?

Offline Jim

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #593 on: 07/26/2017 09:44 pm »

The CH-53E can carry slung loads of up to about 36,000 lb, while the Dragonfly test article was about 14,000 lb.

What's your basis for stating that Dragon would be too heavy for it to lift?

The service ceiling is only around 18,000 ft and it would be much lower with such a load.  And 18k ft itself, is likely too low for such a test.

This is for qualification.  It would be flight weight spacecraft, much heavier than Dragonfly
« Last Edit: 07/26/2017 09:45 pm by Jim »

Offline envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #594 on: 07/26/2017 11:41 pm »
DragonFly was actually ~18,000 lb (8150 kg) when including the fuel load, which is probably more reflective of flight weight after entry. It would be heavier pre-entry with the trunk and unpressurized cargo. It could well be that no helicopter with that load can reach the combination of altitude and speed needed to simulate landing.

A cargo plane or balloon might, though. Starliner recently used a balloon to reach 40,000 ft, and SpaceX has used plane drops for Dragon parachute tests.

Offline JBF

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #595 on: 07/27/2017 12:13 am »
If I had to guess, it all came down to NASA was not willing to let them experiment with the cargo dragon in order to prove out the design and SpaceX was unwilling to fund it alone once they decided that it was not the best way to do things.
"In principle, rocket engines are simple, but that’s the last place rocket engines are ever simple." Jeff Bezos

Offline Comga

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #596 on: 07/27/2017 02:36 am »
how are you going to drop a spacecraft with hypergols? (Snip)

Please explain your comment about hypergols
Hypergols mean it can't be carried within a C5?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline drnscr

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #597 on: 07/27/2017 03:19 am »
Well, if I were on that C5, I damned sure wouldn't want a crap load of hypergols on the same plane as me...

Offline Nomadd

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #598 on: 07/27/2017 04:16 am »
 It's not so much being on the plane as what happens if it flunks the test.
« Last Edit: 07/27/2017 04:16 am by Nomadd »
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline Ike17055

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #599 on: 07/27/2017 04:16 am »
[Steps up on soapbox]
Been stewing this over for the last few days. I am very sad to see Dragon's propulsive landing be cancelled, not because it was sexy or anything like that. It is because like Musk said back at  the D2 Reveal: "This is how spaceships are supposed to land". I believe that with all my heart - I *always* have believed that. Splashdowns were done because back in the day we didn't have a clue how to do anything else. To go back to them 50 years later as the primary recovery is so retro, so 1960's, so chickenshit. We have perfected propulsive landing on Mars for Pete's sake! The Soyuz actually uses it for the final seconds before they hit the ground. Legs coming out through the heatshield scares them? Where are the men who designed Big Gemini with a crew access hatch through the heatshield? NASA actually approved that design. We learned how to do and perfected propulsive landing on the Moon with crew onboard. Remember the LM? Yea, propulsive landing. Now this. What the hell is NASA thinking? It feels to me like they put on their brain-dead hats and told SpaceX to delete it. No guts. No forward thinking. Absolutely no desire to innovate! No wonder we spent 30 years going around in circles. There aren't any forward thinking people in leadership position at NASA anymore. As far as I am concerned there isn't any leadership at all at NASA anymore. Everybody is afraid of their own shadow. They remind me of the cowardly lion on the Yellow Brick Road. The NASA I grew up with is dead and gone. The NASA I was proud to serve doesn't exist anymore. Instead all we have is this shadow thing.
[Steps off soapbox]

Too many red herrings to even address...

Yes, splashdowns were done "back in the sixties"...when our space program was at its peak. Cars had wheels then too. Are wheels now outdated?

Propulsive landing on the moon...yes, in a very limited gravity well, not like Earth.

Propulsive landing on Mars...yes, but not with crew at risk.

Heat shield crew hatch? Yes, but it never was allowed to fly, and was never revisited for future projects.

NASA isn't brain dead, and they are not forgetting that Challenger and Columbia could have sunk the manned space program if people believed that NASA was reckless.

Reliability is not a dirty word. And proven technologies are not bad either. Soyuz is the most successful spacecraft ever...yet it is using "old technology."  America has been grounded several times over the years, several times for multiple years, in its quest for the newest...yet Some variant of Soyuz has flown through all of them, even carrying America back into space on the heels of its (temporary) failures. NASA is proving it is not afraid to learn from history, from its past mistakes, and yes, even from the Russians. That is not brain-dead, that is smart. Very smart.
 


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