Space flight point of no return

[Pawelk198604]

I'm rather lousy rocket designer even in KSP standard

I always wonder what mean when spacecraft Space Shuttle or Soyuz pass the point of no return, what this actually mean???

[Kimberly]

I'm rather lousy rocket designer even in KSP standard

I always wonder what mean when spacecraft Space Shuttle or Soyuz pass the point of no return, what this actually mean???

After dropping the solid rocket boosters, the Space Shuttle initially had (what a sad tense to use!) enough delta-V to turn around, kill its velocity using the main engines and to speed up enough to glide back to the runway. This meant that, if a problem presented itself during launch, they could abort the mission. After picking up too much speed and getting too far away from the runway, the shuttle would no longer have enough delta-V to get back to the runway, and would be forced to continue the mission--that's the point of no return. After the point of no return, the shuttle still had the option of speeding up a little and landing at an airstrip in Europe, or otherwise getting into orbit and then deorbiting itself after going around the planet.

As you can imagine, flipping the shuttle and burning back to the launch site is a mildly insane maneuver, so it was only reserved for very critical problems (and never ended up being used).

Edited August 25, 2013 by Kimberly

[deadshot462]

Well it could be a few things, but most likely it meant that during launch, the rocket passed a point where the crew could not fly back to the launch point if a failure occurred. They would have to either land at a secondary landing spot, or orbit all the way around and land back to the original point.

[Nibb31]

Not sure in what context you heard that phrase, but it doesn't sound like something any space engineers would use. It really depends on what phase of the mission you are talking about.

It might refer to the point during a launch where, instead of aborting by trying to return to the ground (with the LES or an RTLS or transatlantic abort mode for the Shuttle), you abort to orbit by cutting the engines and riding it out until you reenter.

[magnemoe]

For planes point of no return is then ground speed would not make braking possible anymore, you either take off or crash.

Space shuttle had totally different escape options than Soyuz who has an escape tower and no solid fuel boosters, you can trigger the abort button at any time, this kills all engines, separate the Soyuz from rocket and even the service module part and fire up the escape tower rockets. You drop the launch tower at some point probably after second stage has ignited and you are out of the thick atmosphere. At this point you option is to kill all engines separate the landing module and return suborbital.

Once you reach orbit an engine fault might leave you stranded.

For the space shuttle you had to wait until the solid rockets burned out, you could not turn around as you would travel at supersonic speed in the atmosphere and later suborbital, earliest escape would be to jettison the fuel tank and do an gliding reentry and bailout over the Atlantic before splashdown. Some more speed and you might do an landing one some airports in Africa, think some was upgraded for this.

[Kimberly]

For the space shuttle you had to wait until the solid rockets burned out, you could not turn around as you would travel at supersonic speed in the atmosphere and later suborbital, earliest escape would be to jettison the fuel tank and do an gliding reentry and bailout over the Atlantic before splashdown. Some more speed and you might do an landing one some airports in Africa, think some was upgraded for this.

Returning to the landing site was definitely an abort option that was planned for, and which the shuttle was quite capable of doing in theory--though the maneuver would be risky.

[Nibb31]

The RTLS (Return to Launch Site) manoeuver was quite dangerous and only done in the simulator. There is an orbiter video of one here:

As you can see, it involved waiting for SRB separation, pitching to turn around (with a full tank), burning retrograde to reverse the trajectory, and rolling the orbiter to drop the tank. Pretty hairy...

The Transatlantic Abort (TAL) was for aborts that would occur later on in the flight and was preferred over the RTLS. The TAL sites were a select list of landing strips, usually in France or Spain, depending on the launch profile, that were long enough for the Shuttle to land and were manned by NASA personnel during each launch. A C130 was dispatched with the equipment for safing the Shuttle and crew after landing.

Other abort modes are discussed here: http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes

Edited August 25, 2013 by Nibb31