Lots of Questions about reusable rockets and other stuff

[Elthy]

I have to much small questions to make one thread for each, so im posting them all together:

About reusable rockets:

1. Whats the flight profile of an reusable Falcon 9 that launches to LEO and lands on land? Im especialy interested about the point of separation (remaining fuel in the first stage, Delta-V of the second stage).

2. How often did the RCC heat shield parts of the space shuttle need servicing/replacement?

Surprisingly they were never replaced and lasted the whole lifetime of the orbiters.

3. Are there other reentry vehicles with a reusable heat shield? What materials do they use?

4. How much servicing did the RS-25 need until it could fly again. Which parts did need to be replaced how often? How often did they have to replace the whole engine and why?

5. What kind of serving did the other spaceshuttle propulsion components (RCS/OMS) need?

Other questions:

6. Are there non-toxic propelants for RCS/orbital maneuvering (with higher thrust, usable for stuff like docking)?

7. Are there numbers of reentry temperature of low desity objects like the orange tank of the space shuttle?

8. Is an aerospike usefull if its only used in more than 50km of height? Any advantage other than the good ISP scaling from groundlevel to space?

About electrical propulsion:

9. If i understand that correctly for a given electrical power you can choose between higher ISP or higher thrust of an ion thruster or VASIMR. How does that relation look like?

10. Are there Ion engines powered by Argon instead of Xenon or highly corosive elements like Mercury? How does the performance change?

11. Whats the best power/mass we currently have for solar panels?

12. How fast do solar cells degenerate in interplanetary space?

13. How would a low thrust transfer to mars look like?

14. How long would it take to achive earth escape velocity with electrical propulsion?

More other questions:

15. Are there regular free return trajectorys for mars? How much delta-v do they need at earth, whats the relative velocity to mars on flyby, whats the relative velocity when back at earth?

16. How harsh is areocapture on mars when coming on a hohmann trasfer orbit? Does it require an ablative heatshield? How bad is it on the way back to earth?

 

Im sure there will be more...

Edited December 5, 2015 by Elthy

[kunok]

This is the only I know without need for research:

6- Buran used a kerosene and oxygen based OMS, turbine-fed with a relatively good isp. I don't know if other spacecraft used non-toxic systems

[Bill Phil]

#2, every flight had a very intensive check of the tiles. Ones that needed replacement were replaced, missing ones were replaced, etc.

[Nibb31]

 

2. RCC panels were only used on the wing edges and the nose. They did not need replacing. In fact after Columbia, there were no spares that could be used for testing so they had to cannibalize the RCC panels from Enterprise.

3. SpaceX Dragon uses PicaX, which is supposed to be reusable. The Shuttle used 3 different TPS materials depending on which part of the shuttle it was on.

4. The SSMEs were removed and rotated so that they were mixed around and assigned to different orbiters. This was because the servicing cycle was longer for the engines than for the orbiter.

[Bill Phil]

Oh, I thought the RCC panels were the regular shuttle tiles... I don't know or use many acronyms.

Edited December 5, 2015 by Bill Phil

[Elthy]

Thanks for the answers. Ive read something about Pica-X from SpaceX homepage and it seems that while its ablative, it still can be used several times since it wont ablate completly. Seems kinda stupid, can they make it thinner (and lighter) and just build several of them?

[Nibb31]

1 hour ago, Bill Phil said:

Oh, I thought the RCC panels were the regular shuttle tiles... I don't know or use many acronyms.

This article is interesting and explains everything:

https://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system

[Elthy]

Come on, here are so many smart guys, i hope we can answer more questions!

Edited December 6, 2015 by Elthy

[Nibb31]

Your questions are a bit too specific. Either they answers aren't public knowledge or they would need a lot of calculation to answer.

[Steel]

On 12/5/2015, 6:20:51, Elthy said:

I have to much small questions to make one thread for each, so im posting them all together:

...

7. Are there numbers of reentry temperature of low desity objects like the orange tank of the space shuttle?

...

10. Are there Ion engines powered by Argon instead of Xenon or highly corosive elements like Mercury? How does the performance change?

...

13. How would a low thrust transfer to mars look like?

14. How long would it take to achive earth escape velocity with electrical propulsion?

...

7. there's not very much data on these types of objects as they tend to break up on reentry.

10. VASIMR is  planned to run on Argon AFAIK

13.   

something like this perhaps.

14. Depends entirely on the engine and the spacecraft