Liquids do fail benignly. They give enough notice to abort.
As for valuable technology, SRB is not, we can do without.
The rest of your points are actually in favor of liquids and especially, your use of 51-F. The engine "failure" was benign. And if there was another engine shutdown, crew loss would not be due to the engines, but to the program for not having an intact abort system.
Actually I'm not in favor or against either. I am however against throwing out one technology without due studying.
There were plenty of SSME failure modes that would not be so benign. It was one of the reasons for putting the AHMS on the SSME. Monitoring the freqencies of the engine vibrations wasn't cheap but it did provide additional safe-guards which wouldn't be necessary if all liquid engines gave plenty of warning of an upcoming failure. I suppose we could start with the AJ-26 as an example of a catastrophic engine failure that luckily occurred on the test stand. Even on the test stand that wasn't caught in time.
Solids have advantages as do liquids - certainly the ability to throttle a liquid can be an advantage, although the failure mode of getting stuck in the bucket can't occur with a solid.
I really don't see this as cut 'n' dry either way. A liquid booster back in the early days of Shuttle would have had some interesting effects, including development budget. It also would have generated many more abort mode possibilities (ways to do aborts) and also generated many more ways of getting into aborts (intact and contingency).
And could you explain this better? - "And if there was another engine shutdown, crew loss would not be due to the engines, but to the program for not having an intact abort system"
Vehicle loss (I didn't say crew although that was probable) would have been because of lack of energy to reach a TAL site. I can't see that as a program problem but rather a physics problem. At that time, the program had not put in as much contingency abort work as we had at the end of the program and even then it would have been "dicey" to reach a site.
Andy
Not sour one bit - I don't have a pony in this race.
However, you might want to go back and look at the history of liquid engine failures before stating that they fail benignly. There are many examples of one engine taking out another. Either type of engine/motor (solid or liquid) carries risk or else we would have never needed to put in many of the Shuttle contingency modes. To dismiss one type without analyzing the risk of the other is not good program management or engineering. I'd also point out that we had 5 pad aborts and 1 ATO, each of which was caused by a shutdown of an SSME (contained SSME failure - even if it was just a sensor). There were hazards with each abort but crew and vehicle survived. There was 1 failure of the SRM (prior to being redesigned) and obviously we know that result. However, the 51F ATO could have easily ended up as a loss of vehicle had a second engine also shutdown (which it came very close to doing).
There are some liquid engine failures that occur so fast that not even the best avionics can prevent the issue (such as a fuel manifold that ruptures very quickly).
Again, if you would like to dismiss an entire technology because of one (yes catastrophic) failure 25 years ago, then you're dismissing a valuable booster. Seems silly to me, but that's your choice.
Lol! No, I meant the booster exhaust probably tasted a bit sour! Like HCl sour.
Not sour one bit - I don't have a pony in this race.
However, you might want to go back and look at the history of liquid engine failures before stating that they fail benignly. There are many examples of one engine taking out another. Either type of engine/motor (solid or liquid) carries risk or else we would have never needed to put in many of the Shuttle contingency modes. To dismiss one type without analyzing the risk of the other is not good program management or engineering. I'd also point out that we had 5 pad aborts and 1 ATO, each of which was caused by a shutdown of an SSME (contained SSME failure - even if it was just a sensor). There were hazards with each abort but crew and vehicle survived. There was 1 failure of the SRM (prior to being redesigned) and obviously we know that result. However, the 51F ATO could have easily ended up as a loss of vehicle had a second engine also shutdown (which it came very close to doing).
There are some liquid engine failures that occur so fast that not even the best avionics can prevent the issue (such as a fuel manifold that ruptures very quickly).
Again, if you would like to dismiss an entire technology because of one (yes catastrophic) failure 25 years ago, then you're dismissing a valuable booster. Seems silly to me, but that's your choice.
Lol! No, I meant the booster exhaust probably tasted a bit sour! Like HCl sour.
Ah! Sorry about that. The smell was much like you walked into chemistry class after the hydrochloric acid lab. The only way out of class was to go back to your van. Maybe more burning than sour but only slightly irritating by the time we got there.
The launches that were at 2AM-ish, meant we were back out there around 5AM, so we would get the morning dew combined with the acid smell (and the SRB exhaust had already been combined with H2O from the SSME exhaust).
When it dried, it left tan-dirt-colored residue spots that were really bad for car finishes (and camera lenses).
In one of the ALT videos, the one where GPC 2 sync is lost, what is 'Go for mode 203'?
In the operational FSW, the ops modes are 1xx for ascent, 2xx for orbit, 3xx for entry, etc. Sounds like they may have been using 2xx for ALT.
What is the distance between each "bay" of the orbiter payload bay?
The payload bay is 60 x 15 feet.
What is the distance between each "bay" of the orbiter payload bay?
Approximately 5 feet. Each bay is divided by a bulkhead.
Why is the aft exterior of the engine compartment covered in black tiles? Does that area experience high heat on re-entry? High heat on ascent? Or is it there to accomodate an RTLS abort mode where the vehicle would fly backwards into its own exhaust for a period of time?
Why is the aft exterior of the engine compartment covered in black tiles? Does that area experience high heat on re-entry? High heat on ascent? Or is it there to accomodate an RTLS abort mode where the vehicle would fly backwards into its own exhaust for a period of time?
Radiant heating from the SSMEs on ascent.
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?
Depends on the payload mass. It could be an ATO.
You can't do a comparison between vehicles like this. It is apples to oranges.
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?
Probably mission-dependent, situation-dependent, performance-dependent; I think that would probably be near a single-engine ATO/TAL boundary.
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?
Would have been an ATO on STS-134 or 135.
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.
I think I might know the answer - PASS source code. Classified!
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.
I think I might know the answer - PASS source code. Classified!
No, it is an inertial measurement like all launch vehicles.
The inertial platform is kept aligned during the countdown. Drift is not a factor for launch vehicles since the flight duration is short.
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.
I think I might know the answer - PASS source code. Classified!
Don't forget flight path angle as well.
PASS (and BFS) source wasn't classified. However it is also not on the ITAR list of things that can be disseminated publicly with foreign nationals present (from a U.S. perspective). It's actually a very big distinction in how you can work on something.
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.
I think I might know the answer - PASS source code. Classified!
No, it is an inertial measurement like all launch vehicles.
The inertial platform is kept aligned during the countdown. Drift is not a factor for launch vehicles since the flight duration is short.
Doesn't the orbiter use fiber optic gyroscopes? I've never been sure how those can drift. The mechanical gyro drift makes sense - friction will drag it ever so slightly in the direction of travel so it gradually loses its inertial frame of reference. But a laser? I know it happens, just been a while since physics!
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.
I think I might know the answer - PASS source code. Classified!
No, it is an inertial measurement like all launch vehicles.
The inertial platform is kept aligned during the countdown. Drift is not a factor for launch vehicles since the flight duration is short.
Doesn't the orbiter use fiber optic gyroscopes? I've never been sure how those can drift. The mechanical gyro drift makes sense - friction will drag it ever so slightly in the direction of travel so it gradually loses its inertial frame of reference. But a laser? I know it happens, just been a while since physics!
No laser gyros. Sorry. Shuttle IMUs were last upgraded in the early-1990s.
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around.
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around.
The SRM segments are stored in the two Surge facilities north of the VAB once they have completed processing in the Rotation, Processing and Surge Facility(RPSF).
This photo shows right aft segment for STS-121 being transported from one of the Surge facilities to the VAB for stacking:
http://www-pao.ksc.nasa.gov/kscpao/images/large/06pd0108.jpg
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around.
RPSF, which is north of VAB. The segments are moved from there to the VAB on a Kamag transporter.
