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53 votes

Is there any reason why a spacecraft would not be able to turn around without a gravity assist?

Let's say you start rolling down from the top of a half-pipe skateboard ramp, and you plan to get back to your starting point. If you stop in the middle of the pipe, it is much harder to climb back up ...
casualPhilosoph's user avatar
50 votes

Is there any reason why a spacecraft would not be able to turn around without a gravity assist?

All the other answers are great, but I think one explanation is still missing: how an interplanetary orbital transfer actually works in practice. The thing is, space is rather big, and things keep ...
Luaan's user avatar
  • 677
49 votes
Accepted

What were the most impactful non-fatal failures on STS missions?

The failures in this answer will be described at a very high level. A long write-up could be done on any of them. References are provided for further reading. Failures Occurring Prelaunch There were ...
Organic Marble's user avatar
41 votes
Accepted

Why are unused launch abort rockets jettisoned rather than used to augment thrust?

The thrust of the Launch Escape System (LES) might look significant, but the total impulse is not (that is, they burn for such a short time, they can't actually impart much delta-V, especially not ...
CBHacking's user avatar
  • 1,532
40 votes
Accepted

Wouldn't it make sense to use parachutes for aborting test flights rather than destroying the whole rocket?

The ability to successfully deploy a parachute still requires some level of stability or control, it's simply not an option for a badly out-of-control rocket. In cases where something goes wrong, the ...
Nuclear Hoagie's user avatar
35 votes

How do you reliably blow up a rocket that was built not to explode?

Well, I can refer you to the Range Safety Wikipedia entry: Two switches were used, ARM and DESTRUCT. The ARM switch shut down propulsion for liquid propelled vehicles, and the DESTRUCT ignited the ...
BobT's user avatar
  • 1,221
32 votes

Could the Apollo lunar ascent stage have separated from the descent stage before touchdown in an emergency?

Yes. There is a lot of good information in this presentation from the June 1966 Apollo Lunar Landing Mission Symposium relative to landing flight design including abort planning. The crucial figure ...
Organic Marble's user avatar
30 votes

Do the solid rocket boosters of the Shuttle and SLS have a self-destruct system and was it activated during the Challenger disaster?

The shuttle stack broke up at ~73 seconds after launch of STS-51L. The Solid Rocket Boosters separated from the other elements and continued flying in a more or less stable manner (surprisingly). ...
Organic Marble's user avatar
27 votes

Why was the SpaceX abort test not initiated by real booster failure?

It was a real failure (albeit triggered externally rather than accidentally), just not the only failure that can happen. and it is the worst case of a series of the most likely failure scenarios: ...
jwenting's user avatar
  • 593
25 votes

Is there any reason why a spacecraft would not be able to turn around without a gravity assist?

I assume that "halfway there" refers to being halfway along the transfer orbit from Earth to Mars, and that by "turn around" you mean reverse direction immediately. There is no reason a spacecraft "...
Brian Lynch's user avatar
  • 4,350
24 votes

Why no parachutes in the Orion AA2 abort test?

The test they were doing didn’t require parachutes. Data-taking ended right after the capsule separated from the tower. Since the capsule’s behavior after that was not part of the test, it could be an ...
Bob Jacobsen's user avatar
  • 12.6k
23 votes

Could the Apollo LM abort mode be engaged after touchdown? What would have happened if it was?

After a nominal landing the crew is waiting for a go from the ground to stay on the Moon. This was called the "Stay/No Stay for T1" and meant that there were no imminent issues requiring an immediate ...
indy91's user avatar
  • 1,981
22 votes

How do you reliably blow up a rocket that was built not to explode?

Thrust termination is the goal of Range Safety in the event of an errant rocket. Rendering the boosters inert is considered secondary, when possible. The Range Safety Officers don't rely on the ...
Connor Garcia's user avatar
21 votes

How would the space shuttle have been retrieved following a TAL out of Vandenberg?

Some work on refueling capability for the SCA was done: Studies were conducted to equip the SCA with aerial refueling equipment, a modification already made to the U.S. Air Force E-4 (modified 747-...
Russell Borogove's user avatar
21 votes
Accepted

Was this a rapid SCHEDULED disassembly? How was it done?

No. I think this is actually the May 23, 1965 A-003 test, described in my answer to the question, Could a spacecraft spin so fast that it spontaneously deconstructs? Notice that the rocket and Apollo ...
Tom Spilker's user avatar
  • 18.2k
20 votes
Accepted

Why didn’t the space shuttle’s engine-out checklists include steps for attempting a relight?

It was impossible to restart the engines in flight. If for no other reason, the pressure/temperature conditions for the "start box"1 were not met in flight. Also, Post Shutdown to Engine Ready was ...
Organic Marble's user avatar
20 votes

Why was the SpaceX abort test not initiated by real booster failure?

You seem to think they were testing in ideal conditions. That's as far from truth as you can get. The abort happened at the moment in flight with worst aerodynamical conditions (called maxQ), when ...
Malky's user avatar
  • 309
19 votes

How was Apollo supposed to rendezvous in the case of a lunar abort?

Lower orbits are faster, higher is slower, so by adjusting orbit altitude you can get an orbit that gains or lags until you are in position do execute a Hohmann transfer. The orbit period is around ...
GremlinWranger's user avatar
18 votes

Was a method available to save the Challenger Crew?

My reading of the function of the SRB manual separation control is that it would not actually trigger a separation while the boosters were firing (bold mine): SRB separation is normally performed ...
Russell Borogove's user avatar
18 votes

What is the problem with aborting a Space Shuttle launch?

There were four types of intact aborts designed for Shuttle (not counting pad aborts). An intact abort is defined as one that returns the Orbiter intact to a runway. In order of least to most ...
Organic Marble's user avatar
18 votes
Accepted

Aborting a de-orbit maneuver

For the shuttle, technically the deorbit burn could be aborted, but the window to do so was extremely limited. Once the deorbit burn was started, one of the key parameters monitored by the crew was ...
Organic Marble's user avatar
18 votes
Accepted

What is done between a scrub and the next launch attempt?

There is a detailed list here of everything that needed to be done for a scrubbed Saturn V launch, which gives an idea of the scale of the problem. Lots and lots of individual tasks to ensure the ...
Andrew is gone's user avatar
17 votes

Why are unused launch abort rockets jettisoned rather than used to augment thrust?

The thrust of the Apollo launch escape rocket was negligibly small when compared to the thrust of the Saturn V first and second stages. The burn time of the launch escape system was negligibly small, ...
Uwe's user avatar
  • 48.7k
16 votes
Accepted

What are SpaceX Starship/BFR proposed abort modes?

There are no published/proposed abort modes for ascent. We can speculate that some incidents can be survived by letting Starship tumble free and light it's own engines to burn to a low orbit or land ...
Saiboogu's user avatar
  • 6,427
16 votes

How was Apollo supposed to rendezvous in the case of a lunar abort?

There were specific procedures for an abort at any time during the powered descent and after landing. The abort case at the planned time of landing (about 12 minutes after PDI) is covered in this ...
indy91's user avatar
  • 1,981
15 votes

When is the Dragon V2 abort system armed?

Now we've had the Crew Dragon In Flight Abort test, this can be answered more definitively. I've not found a stream where it's absolutely crystal clear, but in the NASASpaceFlight coverage, you can ...
James Thorpe's user avatar
  • 1,315
15 votes
Accepted

What does "angle of attack 100%" mean in Apollo abort rules?

It is not angle of attack that the rule refers to. It is Q-alpha which is the dynamic pressure times the angle of attack. The shuttle had pre-calculated Q-alpha and Q-beta structural limits; ...
Organic Marble's user avatar
15 votes

Why no parachutes in the Orion AA2 abort test?

From the article: Tuesday’s launch was more focused on testing the launch abort system itself. The parachutes on Orion have been tested 47 times.
ulatekh's user avatar
  • 251
15 votes

Wouldn't it make sense to use parachutes for aborting test flights rather than destroying the whole rocket?

great question, and it is similar thinking that led SpaceX to attempt to land rockets for re-use. In this case though I don't think it would be safe or practical to attempt recovery of a launch ...
Grandpa's user avatar
  • 151
14 votes

How would the space shuttle have been retrieved following a TAL out of Vandenberg?

Supplementary answer: I've searched the Aviation Week and Space Technology archives for any references to the Easter Island abort site planning. There isn't a lot, but everything I've seen talks only ...
Organic Marble's user avatar

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