Author Topic: NASA Commercial Crew Space Transportation Services: RFI for Round 2  (Read 50399 times)

Offline DanClemmensen

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I don't really think SpaceX is going to propose Starship for CCSTS2, as all of this is too far in the future for that to make sense, but I guess until we see the receipts we won't know for sure.
SpaceX can continue to fly Dragon 2 and make a profit, but they would like to shift to Starship as part of retiring Dragon and F9. The recovery and refurbishment costs of F9 and especially Dragon are high, and that's a whole lot of infrastructure and employees that do not contribute to their self-perceived main mission.

My totally uninformed and uneducated guess: they will bid both. NASA wants multiple CCSTS options anyway. One enormous advantage of Starship to NASA: a single Starship flight replaces two Dragon flights, one Crew Dragon and one Cargo Dragon. And of course a docked Starship  doubles the pressurized volume of the ISS and much more than doubles the usable living space for the crew.

Offline Robotical

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I had meant to say "SpaceX is going to have an uphill struggle getting Starship certified for manned launches this decade". Anyway, the lack of NASA certification will make it difficult for SpaceX to find customers willing to use Starship for crew which in turn means less external funding to develop that aspect of Starship. The other side is receiving NASA's seal of approval would help considerably with potential liability suits. Despite common wisdom, liability waivers don't release companies from any and all liability under all circumstances and what they do cover tends to vary depending on state law, judicial interpretation, the wording of the liability waiver and what's being claimed. While Texas would undoubtedly be quite favorable to SpaceX's side in such a case, they'll likely want to take it slow to avoid opening themselves to charges of gross negligence.
It's not impossible for them to launch crewed Starships this decade, just difficult.

Online Steven Pietrobon

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NASA designs:
... Mercury/Redstone - abort tower jettisoned after booster burnout. No abort possible after that.
... Mercury/Atlas       - abort tower jettisoned after booster burnout. No abort possible after that.
... Gemini/Titan        - no abort system. Crew had ejection seats
... Apollo/Saturn       - abort tower jettisoned after booster burnout. No abort possible after that.
.... Atlas-V/Starliner   - abort tower jettisoned after booster burnout. No abort possible after that.
... Orion/SLS            - abort tower jettisoned after booster burnout. No abort possible after that.

All of these can perform an abort after tower separation (or ejection seats can't be used for Gemini) by using either the re-entry motors (for Mercury and Gemini) or the service module engine. The same option is also available for Vostok, Soyuz, Shenzhou, China's Next Generation Crewed Spaceship and Gaganyaan. As Starship is integrated with the second stage, any problem that involves the second stage losing its integrity during powered flight is a LOC event. That is not the case for the above systems, where the crew can perform an abort and have a chance of surviving.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Zed_Noir

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NASA designs:
... Mercury/Redstone - abort tower jettisoned after booster burnout. No abort possible after that.
... Mercury/Atlas       - abort tower jettisoned after booster burnout. No abort possible after that.
... Gemini/Titan        - no abort system. Crew had ejection seats
... Apollo/Saturn       - abort tower jettisoned after booster burnout. No abort possible after that.
.... Atlas-V/Starliner   - abort tower jettisoned after booster burnout. No abort possible after that.
... Orion/SLS            - abort tower jettisoned after booster burnout. No abort possible after that.

All of these can perform an abort after tower separation (or ejection seats can't be used for Gemini) by using either the re-entry motors (for Mercury and Gemini) or the service module engine. The same option is also available for Vostok, Soyuz, Shenzhou, China's Next Generation Crewed Spaceship and Gaganyaan. As Starship is integrated with the second stage, any problem that involves the second stage losing its integrity during powered flight is a LOC event. That is not the case for the above systems, where the crew can perform an abort and have a chance of surviving.


The chances of surviving an abort  after the escape tower is jettisoned with the NASA spacecrafts on @Clongton's list seems unclear to me. Don't recall if there were any actual tests to abort with NASA crewed spacecrafts equipped with escape tower using onboard propulsion systems after jettisoning the tower.


Kind of moot with the Orion since it had to outrun the SRBs or components of them along with the fireball with the R-4D thrusters that have a low thrust rating.

Offline clongton

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All of these can perform an abort after tower separation (or ejection seats can't be used for Gemini) by using either the re-entry motors (for Mercury and Gemini) or the service module engine. The same option is also available for Vostok, Soyuz, Shenzhou, China's Next Generation Crewed Spaceship and Gaganyaan.

I acknowledge the point you are making Steven, but as far as I know, NASA itself considers such "aborts" as a likely LOC event. I can't speak to the Russian or Chinese spacecraft but I assume they would have similar conclusions because the spacecraft systems are similar.

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As Starship is integrated with the second stage, any problem that involves the second stage losing its integrity during powered flight is a LOC event.

If you re-read my post you will notice that I specifically stated that it was to escape a failing booster (1st stage). I stand by that statement. As for the Starship loosing it's integrity, yes that would likely be a LOC event, but I put that into the same class as all the other "aborts" that use their upper stage engines to attempt to escape after their abort towers have been jettisoned.  ALL of them are likely LOC events. The exception to all of those is Dragon. It has the ability to escape a failing upper stage. It is the ONLY spacecraft capable of doing that.

Spaceflight is, and always will be, dangerous. EVERY crewed launch is a potential LOC event; every single one. At some point one just has to acknowledge that they have done everything they know how to do to mitigate as many risks as possible, bite the bullet, get on the rocket and fly. Every time you get on an airline flight you take exactly the same risk. The only reason there isn't a parachute under every seat along with a life jacket is because of the thousands of successful flights without incident, and yet people do still die from airplane malfunctions. So the solution in spaceflight is to amass a similar number of successful flights, which SpaceX is bound and determined to do. They are only just beginning, so I would advise patience while the numbers accumulate. A hundred years from now spaceflight will be just as common as airline flights today and very few people will think much about the dangers, just like they don't today when boarding an airplane.
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Offline mkent

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NASA designs:

... Atlas-V/Starliner   - abort tower jettisoned after booster burnout. No abort possible after that.

What on Earth are you talking about?  Starliner can abort all the way to orbit.  If it reaches orbit without using its abort engines, it can use the fuel to reboost ISS, among other things.

Quote
SpaceX designs:
... Dragon/Falcon 9 - carries abort system all the way to orbit (Draco engines)
... Starship            - carries abort system all the way to orbit (Raptor engines)

Starship has no abort system.  If Starship fails, the astronauts die.

Offline Jim

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. Don't recall if there were any actual tests to abort with NASA crewed spacecrafts equipped with escape tower using onboard propulsion systems after jettisoning the tower.



Not really needed

Offline Jim

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All of these can perform an abort after tower separation (or ejection seats can't be used for Gemini) by using either the re-entry motors (for Mercury and Gemini) or the service module engine. The same option is also available for Vostok, Soyuz, Shenzhou, China's Next Generation Crewed Spaceship and Gaganyaan.

I acknowledge the point you are making Steven, but as far as I know, NASA itself considers such "aborts" as a likely LOC event. I can't speak to the Russian or Chinese spacecraft but I assume they would have similar conclusions because the spacecraft systems are similar.


Not true, using either the re-entry motors (for Mercury and Gemini) or the Apollo service module engine were viable and planned aborts by NASA.  For Gemini, this was the preferred method over ejection seats when it is viable

Offline Vultur

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Isn't Dear Moon still a thing? If so, Starship will fly humans well before the end of the decade.

Once ocean platforms (Phobos/Deimos and eventual successors) are operating launch rates should go up a lot, building confidence rapidly.

Offline RonM

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If there's a problem with crewed Starship it's the landing.

Online Steven Pietrobon

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Kind of moot with the Orion since it had to outrun the SRBs or components of them along with the fireball with the R-4D thrusters that have a low thrust rating.

Orion would abort at high acceleration using its LAS tower if there was a problem during the SRB burn.

I acknowledge the point you are making Steven, but as far as I know, NASA itself considers such "aborts" as a likely LOC event. I can't speak to the Russian or Chinese spacecraft but I assume they would have similar conclusions because the spacecraft systems are similar.

Do you have a reference for that? ESA shows the ESM being used in an abort after LAS jettison, but doesn't give any LOC numbers. Also, this abort mode was successfully used by Soyuz 18a on 5 April 1975 when the second stage failed to separate. https://en.wikipedia.org/wiki/Soyuz_abort_modes

Quote
If you re-read my post you will notice that I specifically stated that it was to escape a failing booster (1st stage).

Lets look at the numbers.

Starship Second Stage Mass = 120 t dry, 1200 t propellant, 150 t payload = 1470 t
Thrust Vacuum = 3*(200*355/330+220)*g = 12,802 kN
Thrust Sea Level = 3*(200+220)*g - 3*π*2.4*101.325/4= 10,981 kN

Acceleration Vacuum = 12,802/1470 = 8.7 m/s = 0.89g
Acceleration Sea Level = 10,981/1470 = 7.5 m/s = 0.76g

As Starship acceleration is less than 1g from the time of liftoff, for the early portion of flight, Starship can not be used to save the crew in case the first stage fails, as it has insufficient thrust.
« Last Edit: 11/17/2021 06:11 am by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Cherokee43v6

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Kind of moot with the Orion since it had to outrun the SRBs or components of them along with the fireball with the R-4D thrusters that have a low thrust rating.

Orion would abort at high acceleration using its LAS tower if there was a problem during the SRB burn.

I acknowledge the point you are making Steven, but as far as I know, NASA itself considers such "aborts" as a likely LOC event. I can't speak to the Russian or Chinese spacecraft but I assume they would have similar conclusions because the spacecraft systems are similar.

Do you have a reference for that? ESA shows the ESM being used in an abort after LAS jettison, but doesn't give any LOC numbers. Also, this abort mode was successfully used by Soyuz 18a on 5 April 1975 when the second stage failed to separate. https://en.wikipedia.org/wiki/Soyuz_abort_modes

Quote
If you re-read my post you will notice that I specifically stated that it was to escape a failing booster (1st stage).

Lets look at the numbers.

Starship Second Stage Mass = 120 t dry, 1200 t propellant, 150 t payload = 1470 t
Thrust Vacuum = 3*(200*355/330+220)*g = 12,802 kN
Thrust Sea Level = 3*(200+220)*g - 3*π*2.4*101.325/4= 10,981 kN

Acceleration Vacuum = 12,802/1470 = 8.7 m/s = 0.89g
Acceleration Sea Level = 10,981/1470 = 7.5 m/s = 0.76g


As Starship acceleration is less than 1g from the time of liftoff, for the early portion of flight, Starship can not be used to save the crew in case the first stage fails, as it has insufficient thrust.

I am assuming that both of these figures are for the specific engines in question (RVacs and Sea level Raptors).

In this case, it is unlikely they would be fired solo, thus there is a combined 1.65g of thrust.  However, considering most abort systems seem to go around 5 to 6 g from what I have read I do question if it would be sufficient to escape a fireball from the booster stage.

I do, however, strongly agree with the poster several posts up that states that the highest risk portion for Starship is the landing.
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Offline TrueBlueWitt

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Kind of moot with the Orion since it had to outrun the SRBs or components of them along with the fireball with the R-4D thrusters that have a low thrust rating.

Orion would abort at high acceleration using its LAS tower if there was a problem during the SRB burn.

I acknowledge the point you are making Steven, but as far as I know, NASA itself considers such "aborts" as a likely LOC event. I can't speak to the Russian or Chinese spacecraft but I assume they would have similar conclusions because the spacecraft systems are similar.

Do you have a reference for that? ESA shows the ESM being used in an abort after LAS jettison, but doesn't give any LOC numbers. Also, this abort mode was successfully used by Soyuz 18a on 5 April 1975 when the second stage failed to separate. https://en.wikipedia.org/wiki/Soyuz_abort_modes

Quote
If you re-read my post you will notice that I specifically stated that it was to escape a failing booster (1st stage).

Lets look at the numbers.

Starship Second Stage Mass = 120 t dry, 1200 t propellant, 150 t payload = 1470 t
Thrust Vacuum = 3*(200*355/330+220)*g = 12,802 kN
Thrust Sea Level = 3*(200+220)*g - 3*π*2.4*101.325/4= 10,981 kN

Acceleration Vacuum = 12,802/1470 = 8.7 m/s = 0.89g
Acceleration Sea Level = 10,981/1470 = 7.5 m/s = 0.76g

As Starship acceleration is less than 1g from the time of liftoff, for the early portion of flight, Starship can not be used to save the crew in case the first stage fails, as it has insufficient thrust.

Right off the pad, it's going to be tough..
Once you're a ways in the air, you just have to keep it in the air long enough for T-W to go positive before you impact. You will already have some time with ballistic trajectory and even at 0.76-0.89g that extends that trajectory and flight time significantly.
You could also start dumping LOX/Methane overboard rapidly on abort.. to get your T-W positive more quickly.  Correct?
Be an interesting Kerbal run.

Also, engines are run likely at least 5-10% below max pressure for longevity/reusability? On Abort I'm sure they could throttle to well over 100% in attempt to save the crew.
« Last Edit: 11/17/2021 01:43 pm by TrueBlueWitt »

Offline RonM

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I do, however, strongly agree with the poster several posts up that states that the highest risk portion for Starship is the landing.

The abort modes being discussed are not realistic if Starship can't get back to the launch pad. SpaceX wants to land Starship at the pad just like Super Heavy. So, the only option would be to ditch Starship in the ocean and that's not going to be easy to do and keep the crew alive.

Same problem exists after reentry.

Only option without a Starship redesign is to fly it enough times to show it's reliable. Easier said than done, but SpaceX's rapid test and development makes it at least a possibility.

Offline DanClemmensen

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I do, however, strongly agree with the poster several posts up that states that the highest risk portion for Starship is the landing.

The abort modes being discussed are not realistic if Starship can't get back to the launch pad. SpaceX wants to land Starship at the pad just like Super Heavy. So, the only option would be to ditch Starship in the ocean and that's not going to be easy to do and keep the crew alive.

Same problem exists after reentry.
It's a scary thought, but I'm not sure it's that hard to keep the crew alive, assuming the SS makes a "soft" vertical water landing and then flops over. This is not like ditching an airplane. Unless there is hull breach, SS should float just fine. I really would not want to stay in a floating SS for hours, but I would probably survive. It probably floats in a tail-down attitude but not completely vertical. I hope we get to see an example next year.

Offline Jim

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SpaceX wants to land Starship at the pad just like Super Heavy.

no, it doesn't

Offline abaddon

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Before this turns into Yet Another Starship Thread, perhaps we should wait and see if SpaceX even bids Starship...

Offline Hauerg

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It is hard to say what SpaceX will do but it might be possible for SpaceX to offer both crew Dragon and Starship as crew transportation systems. That would mean getting Starship certified.

SpaceX is going to have an uphill struggle getting Starship certified for manned launches. The lack of a crew abort makes it a no-go for NASA and, without NASA's seal of approval, others are unlikely to go for it. The other hurdle is its sheer size will make the companies with serious CLD proposals leery of allowing it to dock, making it difficult for SpaceX to find outside funds to certify it. Dragon is likely to be SpaceX's go-to human launch system for the foreseeable future.
I'm an outsider, so I don't know how this works. I think Starship has about the same crew abort capabilities as Shuttle did, and Shuttle flew 135 times. Has something changed?
Yes. 14 astronauts died @STS-flights.

Offline rcoppola

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0% chance SpaceX offers Starship imo. I'm more interested in how Boeing will position a Round 2 bid before even being operational for the Round 1 contract. Hoping DC-Crew could sneak into this...

Maybe Starship for Round 3 if ISS goes to 2030. But I doubt it. It would be like driving a Mack Truck to pick up some half & half at the corner market. :D
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Offline RonM

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SpaceX wants to land Starship at the pad just like Super Heavy.

no, it doesn't

Wrong, you haven't been paying attention.

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