STS 122, Colombus to the ISS |
STS 122, Colombus to the ISS |
Dec 5 2007, 10:42 PM
Post
#1
|
|
Senior Member Group: Members Posts: 2922 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
Here we are with another Shuttle launch. Only another 1000 days to go. We're going to miss that.
HD television is available @nasa new web site but not for live videos unfortunately. May be one day on the net. On top of Colombus delivery, when Atlantis will leave the ISS, we'll have the 3rd version (out of 4 scheduled) of the 16's ISS expedition crew as follow : Witson - Malenchenko - Anderson Witson - Malenchenko - Tani Witson - Malenchenko - Eyharts Witson - Malenchenko - Reisman It's nice that (the) Atlantis will deliver Colombus (remind me of something) -------------------- |
|
|
Dec 7 2007, 08:58 PM
Post
#2
|
|
Senior Member Group: Members Posts: 1585 Joined: 14-October 05 From: Vermont Member No.: 530 |
Is it a "backup system?" Perhaps "failsafe" is a better term? It sounds like it's an automatic failure-detect system that shuts off the engines if and only if there is some sort of anomaly that empties the tank faster than anticipated. I don't know that there's another automatic system that it's a backup for.
I imagine they're developing protocol to implement the failure-detect manually, and hit the big red button manually. The big question is whether they can assure themselves that they'll have the process in place to react correctly and in time. It would be an unprecedented event in that with the system either working right or disabled they might be doing an abort-to-earth. I wonder if the system engaged when the Challenger's ET disappeared. |
|
|
Dec 8 2007, 05:50 PM
Post
#3
|
|
Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
I don't know that there's another automatic system that it's a backup for. Believe that you're right. I was thinking of it as an additional cue to the flight computers, which really shouldn't need it if the flight profile is nominal. If it's a fail-safe, then that's an even more powerful argument for fixing it instead of flying as-is. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
Dec 8 2007, 06:05 PM
Post
#4
|
|
Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
I'm not sure I got the story straight, but AFAIK the 4 cutoff sensors aren't part of any backup system. In a normal ascent profile they shouldn't be triggered, because you don't want to plan your payload capacity based on running the tanks completely dry.
As far as I'm aware, there's been one problematic flight, STS-93 where there was a hydrogen leak (among other problems, ironically; you can actually see the leak in tracking footage!) leading up to a couple-of-second-early MECO. It was triggered by those same fuel sensors because the shuttle didn't have enough fuel for a nominal MECO before the tanks ran "dry". It was IIRC the oxygen tank that got depleted (counterintuitive because it was an LH2 leak). MECO is forced probably when more than 2 of those sensors (in either tank?) register "dry". Had there been no such sensors, the SSMEs would have run out of propellant and the turbopumps would probably have failed catastrophically. -------------------- |
|
|
Lo-Fi Version | Time is now: 5th June 2024 - 01:49 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |