Author Topic: California Secrets - SpaceX F9 v1.1 Cassiope Launch Party Thread  (Read 290674 times)

Offline ugordan

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Saturn 1B = 1,600,000 lbf
F9 V1.1 = 1,100,000 lbf

1,100,000 lbf is for F9v1.0.

855-ish klbf for F9v1.0 at sea level.

Offline Comga

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removed as redundant with ChrisWilson68's post
« Last Edit: 08/31/2013 07:50 pm by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline bjornl

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There has to be an RCS since they want to do the 3rd burn right before water. If there was no RCS they would not be able to predict orientation. 

How about a (small) parachute ? RCS is ineffective at low altitude.
How is it ineffective? Didn't Antares use RCS during launch?
As for the original statement, why would you need to predict orientation when you can just measure it?

Online Robotbeat

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Heck, Shuttle used RCS for yaw very soon before landing.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline JBF

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How is it ineffective? Didn't Antares use RCS during launch?
As for the original statement, why would you need to predict orientation when you can just measure it?


If you want to slow your decent, the engines need to be pointed at the ground.  If you can't control your orientation who knows where they will be pointing.
"In principle, rocket engines are simple, but that’s the last place rocket engines are ever simple." Jeff Bezos

Offline ChrisWilson68

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Anyone care to venture an opinion about the odds of any of the following happening when Cassiope launches?

1. The launch vehicle at least clears the transporter erector.
2. #1 plus also the first stage successfully completes its first burn (with or without one or more engines out, as long as at the point the burn completes the upper stage is in a position where it could have put the payload in the proper orbit if staging had worked and if the upper stage had functioned properly).
3. #2 plus also the upper stage successfully separates from the first stage.
4. #3 plus also the upper stage successfully lights.
5. #4 plus also fairing separation is successful.
6. #5 plus also the upper stage completes its first burn successfully (so it reaches the intended orbit of the payload).
7. #6 plus also the primary payload is deployed successfully into the correct orbit.
8. #6 plus also the five secondary payloads are deployed successfully into the correct orbits.
9. #6 plus also the upper stage successfully restarts.
10. #9 plus also the upper stage successfully burns until its propellants are depleted.
11. #3 plus the first stage is successfully oriented for its second burn.
12. #11 plus the first stage successfully relights three engines for its second burn.
13. #12 plus the first stage successfully completes its second burn to reduce its speed before re-entering the thicker parts of the atmosphere.
14. #13 plus the first stage successfully retains the intended attitude down to the altitude where the third burn is intended to begin.
15. #14 plus the first stage successfully relights the center engine to start its third burn.
16. #15 plus the first stage successfully completes its third burn to come to a landing just above the surface of the water.
17. SpaceX recovers the first stage more-or-less intact
18. #16 plus we get to see video of the stage doing its water landing.
19. #7 plus #8 plus #10 plus #16 plus #17 plus #18.
20. #19 plus someone on this forum says the flight was a failure and/or meaningless.

Offline Lars_J

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Surely you have more questions to ask in one post, right? ;-)

Online meekGee

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Anyone care to venture an opinion about the odds of any of the following happening when Cassiope launches?

1. The launch vehicle at least clears the transporter erector.
2. #1 plus also the first stage successfully completes its first burn (with or without one or more engines out, as long as at the point the burn completes the upper stage is in a position where it could have put the payload in the proper orbit if staging had worked and if the upper stage had functioned properly).
3. #2 plus also the upper stage successfully separates from the first stage.
4. #3 plus also the upper stage successfully lights.
5. #4 plus also fairing separation is successful.
6. #5 plus also the upper stage completes its first burn successfully (so it reaches the intended orbit of the payload).
7. #6 plus also the primary payload is deployed successfully into the correct orbit.
8. #6 plus also the five secondary payloads are deployed successfully into the correct orbits.
9. #6 plus also the upper stage successfully restarts.
10. #9 plus also the upper stage successfully burns until its propellants are depleted.
11. #3 plus the first stage is successfully oriented for its second burn.
12. #11 plus the first stage successfully relights three engines for its second burn.
13. #12 plus the first stage successfully completes its second burn to reduce its speed before re-entering the thicker parts of the atmosphere.
14. #13 plus the first stage successfully retains the intended attitude down to the altitude where the third burn is intended to begin.
15. #14 plus the first stage successfully relights the center engine to start its third burn.
16. #15 plus the first stage successfully completes its third burn to come to a landing just above the surface of the water.
17. SpaceX recovers the first stage more-or-less intact
18. #16 plus we get to see video of the stage doing its water landing.
19. #7 plus #8 plus #10 plus #16 plus #17 plus #18.
20. #19 plus someone on this forum says the flight was a failure and/or meaningless.


The only thing I'll put odds on is the second part of #20.... 

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Offline spectre9

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I have no idea if half of those things are ever going to be confirmed by SpaceX.

Offline pippin

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Offline renclod

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14. #13 plus the first stage successfully retains the intended attitude down to the altitude where the third burn is intended to begin.

14.1. first stage successfully deploys a programmer parachute

« Last Edit: 09/01/2013 01:01 am by renclod »

Offline renclod

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Anyone care to venture an opinion about the odds of any of the following happening when Cassiope launches?

16. the first stage successfully completes its third burn to come to a landing just above the surface of the water.

*AND*

18. we get to see the video


Not in the year of grace 2013... IMO

« Last Edit: 09/01/2013 01:00 am by renclod »

Offline simonbp

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If it works, we'll see the video. If not...

Offline Joffan

Anyone care to venture an opinion about the odds of any of the following happening when Cassiope launches?
1. The launch vehicle at least clears the transporter erector. 99.5%
2. #1 plus also the first stage successfully completes its first burn (with or without one or more engines out, as long as at the point the burn completes the upper stage is in a position where it could have put the payload in the proper orbit if staging had worked and if the upper stage had functioned properly). 90%
3. #2 plus also the upper stage successfully separates from the first stage. 89%
4. #3 plus also the upper stage successfully lights. 86%
5. #4 plus also fairing separation is successful. 83%
6. #5 plus also the upper stage completes its first burn successfully (so it reaches the intended orbit of the payload). 78%
7. #6 plus also the primary payload is deployed successfully into the correct orbit. 75%
8. #6 plus also the five secondary payloads are deployed successfully into the correct orbits. 75%
9. #6 plus also the upper stage successfully restarts. 70%
10. #9 plus also the upper stage successfully burns until its propellants are depleted. 69%
11. #3 plus the first stage is successfully oriented for its second burn. 75%
12. #11 plus the first stage successfully relights three engines for its second burn. 70%
13. #12 plus the first stage successfully completes its second burn to reduce its speed before re-entering the thicker parts of the atmosphere. 50%
14. #13 plus the first stage successfully retains the intended attitude down to the altitude where the third burn is intended to begin. 15%
15. #14 plus the first stage successfully relights the center engine to start its third burn. 12%
16. #15 plus the first stage successfully completes its third burn to come to a landing just above the surface of the water. 2%
17. SpaceX recovers the first stage more-or-less intact 1%
18. #16 plus we get to see video of the stage doing its water landing. 2%
19. #7 plus #8 plus #10 plus #17 plus #18. 0.5%
Getting through max-Q for humanity becoming fully spacefaring

Offline edkyle99

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That adds complexity to an inaugural flight.  I suppose that the cold gas RCS will also have to do the ullage thrusting prior to engine restart.  Still, I've seen no hint of this RCS hardware in any photos so far.

 - Ed Kyle

No need to use the RCS for that purpose IMO. The atmosphere will do that in time. No need for braking thrust as long as the atmosphere is too thin.

The idea is to cancel horizontal velocity before the stage hits the atmosphere, to minimize reentry heating and reentry forces. 

 - Ed Kyle

Offline ChrisWilson68

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Anyone care to venture an opinion about the odds of any of the following happening when Cassiope launches?
1. The launch vehicle at least clears the transporter erector. 99.5%
2. #1 plus also the first stage successfully completes its first burn (with or without one or more engines out, as long as at the point the burn completes the upper stage is in a position where it could have put the payload in the proper orbit if staging had worked and if the upper stage had functioned properly). 90%
3. #2 plus also the upper stage successfully separates from the first stage. 89%
4. #3 plus also the upper stage successfully lights. 86%
5. #4 plus also fairing separation is successful. 83%
6. #5 plus also the upper stage completes its first burn successfully (so it reaches the intended orbit of the payload). 78%
7. #6 plus also the primary payload is deployed successfully into the correct orbit. 75%
8. #6 plus also the five secondary payloads are deployed successfully into the correct orbits. 75%
9. #6 plus also the upper stage successfully restarts. 70%
10. #9 plus also the upper stage successfully burns until its propellants are depleted. 69%
11. #3 plus the first stage is successfully oriented for its second burn. 75%
12. #11 plus the first stage successfully relights three engines for its second burn. 70%
13. #12 plus the first stage successfully completes its second burn to reduce its speed before re-entering the thicker parts of the atmosphere. 50%
14. #13 plus the first stage successfully retains the intended attitude down to the altitude where the third burn is intended to begin. 15%
15. #14 plus the first stage successfully relights the center engine to start its third burn. 12%
16. #15 plus the first stage successfully completes its third burn to come to a landing just above the surface of the water. 2%
17. SpaceX recovers the first stage more-or-less intact 1%
18. #16 plus we get to see video of the stage doing its water landing. 2%
19. #7 plus #8 plus #10 plus #17 plus #18. 0.5%

Thanks for being brave enough to put down some concrete numbers!

I see you have big drops from #13 to #14 and from #15 to #16.  I agree with you about a big drop from #13 to #14.  But I'm more worried about the odds of #15 given #14 than of #16 given #15.  I think Grasshopper has shown SpaceX knows how to land it if it's intact enough that the  center engine lights.  I think there's a significant danger that falling all that way through the atmosphere will do enough damage to prevent a successful engine relight even if the attitude is correct.

For #1 through #10 I more-or-less agree with your numbers.  Everything after that is much more speculative.  I'm somewhat more optimistic about #16 and #17 than you are, with similarly more optimistic numbers for some of the other #11-#20 items.  I'd put the odds of #16 and #17 at more than 10%.

Offline QuantumG

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Everything will go perfectly and SpaceX will move up their schedule, attempting a boost back to the launch site on the next flight.

 ::)
Human spaceflight is basically just LARPing now.

Offline ChrisWilson68

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That adds complexity to an inaugural flight.  I suppose that the cold gas RCS will also have to do the ullage thrusting prior to engine restart.  Still, I've seen no hint of this RCS hardware in any photos so far.

 - Ed Kyle

No need to use the RCS for that purpose IMO. The atmosphere will do that in time. No need for braking thrust as long as the atmosphere is too thin.

The idea is to cancel horizontal velocity before the stage hits the atmosphere, to minimize reentry heating and reentry forces. 

 - Ed Kyle

As I'm sure you know, there's no hard cut-off for the atmosphere.  The ISS experiences some atmospheric drag.  So it's not a question of lighting the stage before it hits any atmosphere at all.  It never entirely leaves it, and there's some drag on the stage the whole way.  It's not too much of a stretch to imagine that the burn won't start until there's enough drag to settle the propellants enough for the engines to work, and that still won't be enough heating to cause problems.

Note that I'm not claiming that it would definitely work, just that we don't know that it wouldn't.  SpaceX has probably run the numbers and at least thinks they know the answer, but I don't think they've publicly said.

Offline ChrisWilson68

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Everything will go perfectly and SpaceX will move up their schedule, attempting a boost back to the launch site on the next flight.

 ::)

Now that's the right attitude for a party thread!

Offline Zed_Noir

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Everything will go perfectly and SpaceX will move up their schedule, attempting a boost back to the launch site on the next flight.

 ::)

Then THE MUSK will be insufferable smug. But never mind that, SpaceX don't have a landing pad yet at VAFB.

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