Shuttle crew helpless to inspect orbiter?!

Great Debates
101

part 2

Corbomite said:

Do you mean on every flight, or just in the case of suspected damage? What is your risk assessment level for likelihood of another loss on reentry? What is your risk assessment of the likelihood of coming down over a heavily populated area?

user_hostile said:

Define what you mean by technologically obsolete. Do you mean just the computer systems, or something more? And again, you want reliable systems for critical functions. Reliable systems are established through use. Thus old technology has a longer history on which to evaluate it. If it gets the job done, then it doesn’t require replacement.

GOM said:

They did have training and equipment to save their own lives. They did not have equipment and training to do things that would put their lives in greater risk. See above about likelihood of causing more damage in the process.

capacitor said:

The two situations are not even remotely similar. That’s like saying because doctors can perform organ transplants, engineers should be able to design a way to replace your transmission while you’re driving down the interstate at 60 mph.

rocking chair

Excellent comparison.

dalovindj said:

Impractical. Your talking about adding something like 4 to 7 Mercury capsules to the orbiter, as a backup return. Four would be more likely, because you reduce crew capability in trade off. Still, there just isn’t room for it. And you drastically impact payload capability, and usefulness of the shuttle. The fewer people that can fly, the more limitations on what it can do.

GOM said:

Suppose you’re driving down the highway at 60 mph. It’s raining (a light rain, so the road is wet but visibility is still good). As you enter a turn, your tire hits something you didn’t see, and a tire blows out. You’re very likely to hydroplane, or at least veer into oncoming traffic. That oncoming traffic is a semi truck. How much chance do you have?

Your first objection will be the two situations are not similar, based on likelihood of occurring. They are. The shuttles are designed to withstand damage to/loss of tiles and still return safely. Not all the tiles, but a significant number. The likelihood of encountering enough damage to destroy an orbiter is not high.

GOM said:

It’s not just total weight, but distribution of weight that must be accommodated. Plus weight is not the only limiting feature. There’s also space. And there’s also fuel budget. These are not trivial changes.

Says who? You? And you’re qualified how?

I tried to check the link you provide, but the article is now archived, and requires payment to read. If it is what I read before, it greatly exaggerates things.

David Simmons said:

Every incident of foam insulation coming off was investigated. Solutions were implemented to previous problems. AFAIK, all incidents of tile coming off were in response to some outside disturbance.

DaddyMack said:

Phoenix Dragon said:

I believe you misunderstood. DaddyMack did not ask how they abort, but rather what conditions would signal a need to abort in enough time to allow an abort. Such as with Challenger, where the first signals were miniscule and didn’t register, only showing up in post-accident review.

Answer, one condition would be the loss of two shuttle main engines. Not just one engine, but two. The Shuttle has three main engines, plus the SRBs. The main engines run on the liquid hydrogen/liquid oxygen mix from the external tank. Usually the loss of one engine will not require abort. It may result in a low orbit, requiring either abort from orbit, or more likely using more OMS to achieve the designated orbit. IIRC, this has happened. Not the abort, the loss of one engine late in flight. Loss of one engine early in flight could conceivably signal abort, but the best scenario would still be abort from orbit. Much better than trying to jettison ET, then roll in atmosphere.

SRB falling off early would require abort. Likelihood of that - very small.

Tuckerfan said:

Moron. No, I’m not calling him a moron, the runway is in Moron, Spain. Pronounced “Mo rone”. :wink:

Sam Stone said:

FYI, the shuttle no longer flies any DoD missions.

Triskadecamus said:

Even worse, “Analysis using computer models correlated to previous experience and using conservative estimates indicates the level of damage is probably not an impact to safety.” Now do you want to be the guy who says, “Let’s scramble to rush a dangerous rescue mission (that we may not be able to pull off in time) and abandon a shuttle, probably to watch suffer an uncontrolled reentry and loss of vehicle.”?

Sorry it’s so long.

102

hmmm

That’s not what I heard…

Sorry I don’t have a link to back that up. I heard it on the radio. However, if DoD wants something put on the Shuttle I don’t think NASA is in the position to say “no”.

103

Interesting story, but completely unrelated to inspecting and repairing the Shuttle over several days or weeks. We cannot lose more lives because of stinkin’ flimsy tiles.

:frowning:

Do an inspection of the tiles after achieving orbit. Give the astronauts a way to fix the damaged tiles, at least the ones in critical areas, and give them a fighting chance to make it home alive. Otherwise keep the remaining Model T Shuttles grounded.

In case you mistake me for someone who opposes the space program, I am actually in favor of an effective manned space exploration program. Currently our manned space program is a joke. We can’t even go back to the Moon right now.

It’s not all NASA’s fault, btw, in case you think I’m hammering NASA.

104

If the shuttle doesn’t fly DoD missions, how could they get a KH-11 class satellite into orbit? As far as I know, there are no other boosters in the U.S. inventory capable of lifting something that big.

105

If it was the Time’s article, it not only exaggerates things, but it seems to show a gross lack of understanding of how the Shuttle, and spaceflight in general, works.

Can you really not see the impracticality, hell, the near impossibility of what you’re proposing? Every single tile is different, there is no “generic” tile you can use. The adhesives that could be used in space has been found to compromise performance. It takes several man-days to replace a single tile, when you’re working on the ground, in gravity, without some bulky EVA suit in the way. Durring those several man-days of labor, you’re VERY likely to damage even more tiles, making the situation much worse than it started. Even just trying to fix “critical areas” isn’t any better, since the tile you’re replacing compromises performance (possibly making it worse), and all the damage you cause in the process will be in that critical area (DEFINATLY making it worse)!

It’s been pointed out several times, and the only thing I’ve seen you reply with is “I’m sure they can work it out.”

Once again; reentry is probably the single most abusive and violent activity any vehicle can be subjected to. There is a reason three of the four manned in-flight disasters have been on reentry. The Shuttle, however, is built to not only go through reentry, but do it dozens of times, with a higher safety record than any other currently availible launch system. This isn’t the sign of a vehicle that is “broken.”

106

I question this. It seems to me that based on either number of mission failures per launch or number of fatalities per launch, the Soyuz far outperforms the Shuttle. Suyuz capsules have only claimed 4 crew member lives (versus 14 for the Shuttle) and have flown far more missions than the Shuttle system. Unless you meant to compare the Shuttle only to other re-useable launch systems, or other manned systems capable of carrying similar cargo loads and crews, in which case it isn’t much of a comparison as there aren’t any.

107

Most planned Shuttle/DoD missions were moved from Shuttles to Expendable Launch Vehicles (one-time use rockets in NASA-speak) after the 1986 Challenger accident.

For example, STS-62-A would have been a Shuttle/DoD mission in Fall 1986.

 http://www.astronautix.com/flights/sts62a.htm

The last acknowledged Shuttle/DoD mission was STS-44 Atlantis in November 1991. It launched a Defense Support Program satellite.

 http://www-pao.ksc.nasa.gov/kscpao/chron/sts-44.htm

All KH-11 satellites were launched by Titan 3D and 34D rockets from Vandenberg.

  http://www.astronautix.com/craft/kh11.htm

One of three KH-12 satellites was launched on STS-36 Atlantis on 2/28/1990. The next two were launched on Titan 4 rockets.

 http://www.astronautix.com/craft/kh12.htm

FYI - Every wonder how NASA was going to have dozens of shuttle launches a year? They were going to have three launch sites (39-A and 39-B at Cape Canaveral and SLC-6 at Vandenberg) and turn the shuttles around between launches in weeks, instead of the months post-Challenger. Here’s the schedule of planned flights that were cancelled post-Challenger. (The first digit after STS is the last digit of the year of launch, the second digit is a 1 for Cape Canaveral or a 2 for Vandenberg, the letter is the order of flights in that year, e.g. 62-B is the second flight in 1986 from Vandenberg. Due to changes in flight schedule, the actual launch date may not have matched the STS sequence, e.g. 51-L (Challenger) launched in 1986.)

  • 1986 March - STS-61-E.
  • 1986 May - STS-61-F.
  • 1986 May - STS-61-G.
  • 1986 June - STS-61-H.
  • 1986 July - STS-62-A.
  • 1986 July - STS-61-M.
  • 1986 August - STS-61-J.
  • 1986 September - STS-61-N.
  • 1986 September - STS-61-I.
  • 1986 September - STS-62-B.
  • 1986 October - STS-61-K.
  • 1986 November - STS-61-L.
  • 1986 December - STS-71-B.
  • 1987 January - STS-71-C.
  • 1987 January - STS-71-A.
  • 1987 February - STS-71-D.
  • 1987 March - STS-71-E.
  • 1987 March - STS-71-F.
  • 1987 August - STS-71-M.
  • 1988 February - STS-81-G.
  • 1988 July - STS-81-M.
108

No, I mean of all launch systems. This page has been mentioned a couple times on the SDMB, and I think in this thread, too.

First off, saying the Soyuz has only claimed 4 lives compared to the 14 shuttle deaths is a bit skewed. A more accurate comparison for safety would be to point out that both the Soyuz and the Shuttle have had two manned in-flight disasters. The Shuttle carried 7 on both, while the smaller Soyuz carried 3 on one mission, and a single astronaut on another. Also, while the Soyuz flies more frequently than the Shuttle (10 or more per year), the Soyuz flies much fewer manned missions than the shuttle. It’s been averaging two missions per year (For at least the past decade, hard to find info prior to that), wheras the Shuttle averages 6. And when an un-manned Soyuz blows up, it’s unlikely to be major international news, even when it kills someone on the ground.

So, the Soyuz flies manned missions about 1/3 as often as the Shuttle, but has still resulted in the death of the crew the same number of times. The only reason it’s caused fewer deaths is because it carries fewer people. I’d go with the Shuttle, personally.

109

Comparing manned and unmanned launch system failure rates is a bit of apples and oranges, really. You’d expect the manned launches to have a much lower failure rate, considering the significant extra care that’s put into any system carrying a live crew. The question really is what do you consider when calculating safety record, the number of launch failures, or the number of crewmembers killed per flight? Which brings up the question of wether it’s a good idea to try and build a heavy cargo lifter that also carries a manned crew, or if the jobs of crew transport and cargo lifter should be dedicated to different vehicles. NASA’s new OSP project looks like a step in the right direction, a reuseable crew thansfer vehicle that doesn’t try to do a half dozen other jobs at the same time.

By the way, the dedicated crew transfer versions of the Soyuz, the Soyuz-T, TM, and TMA, have never killed a crewmember. This despite failures (including a booster rocket exploding on the launch pad in one case) that would have been unsurvivealbe in the Shuttle. Unlike the Shuttle the Soyuz crew can actually escape if there’s a catastrophic failure early in liftoff.

110

http://www.spaceflightnow.com/shuttle/sts107/030221tpsrepair/

In January 1980, NASA announced a contract to develop a kit for astronauts to repair damaged heat shield tiles on the space shuttle.

Some details:

“The kit weighs about 300 pounds and will be stored atop the Auxiliary Equipment Storage Assembly in the Orbiter cargo bay.”

"Each kit will contain 160 replacement blocks. "

“The cure-in-place ablator is a paste-like substance with a silicone-rubber base. It will be applied with an applicator which resembles a conventional caulking gun.”

"If necessary to perform repairs, a spacesuited astronaut would don a backpack maneuvering unit in the Shuttle cargo bay, inspect the outside of the Orbiter, and if necessary, use the kit to apply the ablative materials. "

No details on whether the kit was ever completed or ever flown on a Shuttle mission. The “backpack manuvering unit” was developed, the Manned Maneuvering Unit, but has not been used post-Challenger.

111

Rillian, it’s already been stated. The kit was not completed, never flown. Primary reason was that testing showed that the “silicone-rubber base paste-like substance” reduced the performance of the tiles, both aerodynamically and thermally. Also, even with the MMU, there is still concern over the ability of the astronauts to work around the tiles without damaging more of them. The MMU would make it a lot better, but is not a guarantee. And even using the MMU to get you to the underside, there is still no way to hold onto the bottom of the shuttle. Any technique developed to do so would be attached to more of the fragile tiles. The MMU cannot provide a stable platform for work. It would need a reactive thruster on computer sensor for transient loads. Think about it. Any activity by the astronaut to touch the shuttle is going to impart a load on him. The more contact, the more force. If he’s not rigidly attached to the shuttle, the MMU has to counter those forces.

GOM said:

My point was that you will always have situations that cannot be fixed, that you can do nothing about.

Look, it boils down to this: the probability of doing enough damage to the tiles to prevent a safety hazard is incredibly low. If you get enough damage to worry about it, the probability of making the situation worse trying to repair it is very high. What’s the doctor’s adage, “First do no harm”? If the only thing you can do is make things worse, then why would you want to do anything?

And again, the investigation is still working out exactly what happened, but by no means has the failure been determined to be strictly tile loss. The investigation is pointing at a breach in the aluminum skin. If it turns out to be from a whole in the skin, then it doesn’t matter how bad the tiles were. So it’s still early to blame Columbia on tile damage.

Just to speculate a little, suppose the tile damage incident also caused the breach in the skin. That’s improbable, but not ruled out as of now. In that situation, it might make sense to do an inspection, because you’re not just looking for damage to tile, but damage below the tiles. Now your inspection technique (say robotic camera) must be able to discern damage below the tiles, and below the felt layers used to isolate the tiles from the structure due to thermal expansion. Even if the tile is fractured or missing, it still not likely to see if the damage is more extensive. Now your inspection needs to be able to look for millimeter sized holes in the aluminum skin under the tiles and/or felt.

Hey, I’ll admit the shuttles never lived up to the reusability promise that was the original goal. I’d be happy to see more investment in space development, including work on new launch systems that increase access to space while decreasing cost and maintaining or improving safety. But I’m not ready to give up on the system we have and do nothing until a replacement is ready. We did that once. And everyone since has called it the stupidest decision NASA made. Let’s not do it again.

We have yet to show that the shuttles are unsafe. There is certainly the debris problem that would have needed to be run down anyway. There is a need to finish the investigation, and determine if there was some other event that contributed, such as orbital debris hit, lightning strike, gremlins, whatever. Once that’s done, we can evaluate the safety issues and determine what needs to be done to prevent it from occurring again, or reduce the probability. Because I want to keep the astronauts as safe as possible, too.

112

  1. I find that extremely hard to believe. Is the skin that thin? I thought the tiles fell off over California (we have at least one witness who says that) and then the skin got burned through by the heat as Columbia came back into the atmosphere.

  2. True. They didn’t meet the (unrealistic imo) goals, but part of that could be the fault of Congress for cutting back on funding.

  3. Good point. Not to mention that the ISS is dependent on the Shuttle to stay in orbit, IIRC. It starts to come down in less than a year if a shuttle doesn’t give it another boost.

  4. I don’t know about that… NASA’s latest estimates were roughly one catastrophic failure in 75 flights. That’s not acceptable for human space flight, to me. I’m sure most of the astronauts would be willing to take the risk though…

  5. Right.

  6. We fully agree on that.

113

You might be right. Maybe it can’t be fixed. Maybe it’s hopeless to even try. But frankly that just goes against my nature.

If repairs absolutely cannot ever be made in space, then we need to do more to prevent this type of damage (assuming tiles are the problem) before any more shuttles enter orbit.

FWIW, I would take the $32 billion we’re apparently going to give to Turkey and replace our 40-year-old technology shuttles. But I’m not in charge…

114

NASA may be reading in our thread. In an AP report published on 2/24/2003, the following points are made:

"No matter what the outcome of the Columbia accident investigation, NASA is already taking a much harder look at ways for astronauts to inspect and repair damaged thermal tiles on space shuttles in orbit. "

"The space agency is determined to give astronauts a fighting chance in the future. "

“When we looked at this early in the program, one of the major issues was, you don’t have any stable platform to do any of these things,” said NASA spokesman James Hartsfield. “Now that most of the shuttle flights are for support of the international space station, one thing that will be looked at very closely is whether the station’s robot arm can provide a stable platform.”

115

Interesting…

The wording is very similar. We used to have at least one NASA poster here, but I haven’t seen him for a while. Maybe he still lurks once in a while.

116

Thought I’d bump this because of some photos of Columbia in orbit.

These were taken 4 days before the breakup, for what reason I don’t know. Look at the hi res versions. I’d say there’s a pretty good chance that damage to the underside might have been seen.

The observatory directors are apparently disagree with NASA over the usefulness of imaging from the ground.

Thanks to Squink for providing a link in this thread which lead me to the links I’ve included here.

117

Also some interesting quotes in an AP article, NASA Debated Shuttle Risks for Five Days, today about internal NASA discussions prior to the Shuttle’s return.

118

Most likely this and this:

“Besides the tile issue, speculation on the cause includes extreme aerodynamic stresses on the 90-ton shuttle, which has been likened to a flying brick with wings as it plunges from orbit into the atmosphere, controlled not by engines but aerial flaps.” ~CNN

http://ftp//space.mit.edu/pub/plasma/publications/jdr_opher_nature/jdr_opher_nature08567.pdf

119

The link you post doesn’t go to the site you claim, and the site it does go to has nothing to do with the shuttle that I can tell.

120

And this thread is 8 years old.

Reported.