Linked Questions

46 votes
2 answers
7k views

Why were the Space Shuttle's main engines placed on the orbiter?

Since the main engines can't be used after external tank separation, what's the reason for having the engines on the orbiter rather than just building a third rocket on the stack instead of the ...
Brad's user avatar
  • 878
40 votes
2 answers
5k views

Why doesn't JWST use ion thrusters?

Since the L2 point is unstable, JWST needs engines to maintain its orbit. It uses mono-propellant engines which have given it a 5-year minimum lifespan. Why weren't ion engines used instead? Wouldn't ...
Oscar Smith's user avatar
34 votes
2 answers
5k views

Why is the X-37B's large nozzle offset to right from the spacecraft's mid-plane?

Perhaps I'm naive to think that the single large nozzle at the back of the X-37B is a nozzle for an engine, but regardless of the purpose, gas exiting from a nozzle will produce thrust. Is the X-37B's ...
uhoh's user avatar
  • 149k
31 votes
3 answers
15k views

Why does the SpaceX Falcon 9 rocket do a 180 flip for reentry?

I am very new to the rockets and this can be a very dumb question, just that I am not sure if my understanding here is right? All of the rockets engines are at bottom which help it take off and ...
KP.'s user avatar
  • 421
28 votes
3 answers
7k views

How hard do you have to throw something off the ISS to make it deorbit?

During Expedition 41 Reid Wiseman and Alexander Gerst replaced a failed pump on the outside of the ISS. I am guessing they took the broken pump back inside the ISS and returned it to earth in one of ...
user avatar
21 votes
4 answers
10k views

If the Space Shuttle missed its landing approach, what could have been done?

As I understand it, the Space Shuttle was essentially a glider when it was coming back to land, and the engines were not there to facilitate powered flight. So what was the procedure, had the Space ...
Burhan Khalid's user avatar
20 votes
2 answers
5k views

What eliminates the velocity when occupants return from ISS to earth, and how much?

The ISS has an orbital velocity of ~28000 km/h; the velocity $v$ relative to the landing site of the descent module is probably even higher than that most of the time. Once the occupants have landed, ...
Alexander Klauer's user avatar
11 votes
1 answer
3k views

How did the Space Shuttle keep its cryogenic fuel cold?

As I understand it, the Space Shuttle used cryogenic fuel in its main engines and it kept a supply onboard for the duration of its mission for a deorbit burn. Since Space Shuttle missions often lasted ...
Keavon's user avatar
  • 395
11 votes
2 answers
1k views

Aborting a de-orbit maneuver

I was contemplating on how a de-orbit may be abandoned post completion of the orbit burn, say, from LEO. A situation in which this might be necessary would be detecting a breach in the heat shield ...
William R. Ebenezer's user avatar
9 votes
2 answers
537 views

Orbit stability

This is my first question. I am a space enthusiast but I don't have a formal understanding of celestial mechanics, so I would like to ask how stable against perturbation an orbit is, given the ...
Unai Vivi's user avatar
  • 193
6 votes
1 answer
3k views

What happens to orbit after a radial burn?

We know from Hohmann or bi-elliptic transfer maneuvers that a burn in the tangential direction of an orbit changes the radius of the orbit. But what happens to an object in orbit, when there is a burn ...
user36499's user avatar
5 votes
2 answers
2k views

Is getting IN or OUT of orbit easier for the Space Shuttle? [closed]

Here is a brief dramatic of the Space Shuttle launch and reentry: Launch : You get on this plane like thing that is strapped to an orange fuel tank that looks more like a huge bomb. The fuel tank is ...
Dat Ha's user avatar
  • 1,715
5 votes
1 answer
304 views

After a spacecraft departing from the ISS has performed its deorbit burn, what is the altitude at the perigee of its elliptical orbit typically?

I am attempting to quantify how aggressively returning spacecraft reenter the atmosphere. There is likely a trade-off between aerobraking more gradually and splashing down accurately. I'm hoping that ...
phil1008's user avatar
  • 6,251
4 votes
2 answers
995 views

Deriving the changes in Keplerian Elements induced by small impulses

I'm trying to make derive a concise table of the effects on each Keplerian orbital element for a small impulse in the Radial, Tangential, or Perpendicular direction at periapsis or apoapsis, good to ...
uhoh's user avatar
  • 149k
4 votes
3 answers
386 views

Starship deorbit process

It does not seem to me that SpaceX will use thrusters similar to Draco to deorbit Starship, and I think firing a Raptor would be too powerful. All I can imagine is that it will use ullage gases ...
Douglas Sutherland's user avatar

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