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Crack Found in Shuttle Tank
hpulley writes "The shuttle's new fuel tank, supposedly redesigned to be safer, has a crack in it. Pictures were sent to the manufacturer who decided that it is too small to be worrisome. Hmm, what caused the Columbia disaster, pieces of foam?
Meanwhile, there will be a second shuttle on standby, just in case the first one has problems after being hit by foam, etc. If the first shuttle has a design flaw, what's to say the second one isn't afflicted by the same problem? Won't there be a good chance of them stranding the rescue crew in addition to the original crew? If an aircraft crashes and the redesign to fix it crashes, would you send another of the same type to rescue it? Of course not! The ISS is going to be a smelly, scary place with the regular complement and two shuttle crews onboard and no way home but a Russian Soyuz capsule that isn't slated to launch again until September and has seats for just three..."
If the poster read the suggested articles he would know the crack is in the tank's insulation and not the tank.
If it makes you feel better the shuttles do not use the same computer they did in 81.
They have been updated a lot since they first flew.
The Air Force flys Bombers designed in the 40s and built in the 50s. Fighters that where designed in the 60s and built in the 70s. Even the Boeing 747 was first built in the 60s as was the 737. I agree that the shuttle does need to be replaced but it is not the same shuttle that flew in the early 80s
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
and the first line "The shuttle's new fuel tank, supposedly redesigned to be safer, has a crack in it." The tank does NOT have a crack in it, the foam insulation around the tank has a crack. There is a huge difference.
From wikipedia:
Internally the Shuttle remains largely similar to the original design, with the exception that the avionics continues to be improved. The original systems were "hardened" IBM 360 computers connected to analog displays in the cockpit similar to contemporary airliners like the DC-10. Today the cockpits are being replaced with "all glass" systems and the computers themselves are many times faster. The computers use the HAL/S programming language. In the Apollo-Soyuz Test Project tradition, programmable calculators are carried as well (originally the HP-41C).
According to a couple of people I know who are pilots, the issue with any aircraft isn't physical age, but hours in the air. This is why you can still safely buy and fly a Piper Cub, or, if you're SAC, a somewhat updated B-52, first built back in the '50s.
Those shuttles are probably finally making it to broken in, from an airframe standpoint. (even if they are approaching the day for that one, last, flight to the Air and Space Museum)
the more accurate the calculations became, the more the concepts tended to vanish into thin air. R. S. Mulliken
Your analogy is correct, but remember that most of the early (-100 and -200) 737s, and almost all 747-100s are out of service now, and the 747-200 is well on its way. Now, some of the old Russian planes are still in service for much longer (such as the Aerogaviota An-24 I flew on in Cuba), so what does that say about their reliability? ;)
An Apollo 12 was struck by lighting and still survived to complete its mission successfully (it went to the moon)! The most famous call in NASA history was made by the electronics engineer when he told them to reset the system using 'SCE to aux' which the astronauts found after some searching. And the electronics still worked. Now that is reliable engineering. Now the space shuttle can't withstand foam. But NASA was better funded then, you get what you pay for. Maybe if Bush wants to go to Mars, he should cut the budget. Just a thought...
"Those that start by burning books, will end by burning men."
Linear Elastic Fracture Mechanics. Basically, it's the study of cracks. And, there can exist cracks that won't propagate if the stress intensity is within parameters (usually determined with a safety factor). So the manufacturer probably is confident that the crack is fine. Obviously, no crack is good, but ALL materials crack with life because of fatiguing. There, now you have a mechanical engineer's viewpoint.
Many in the African-American community have charged that the CIA tried to get low-income African-Americans hooked on crack in the 1980's by making it easily available in their neighborhoods. If anything, it's a CIA joke.
Nation of Islam investigates possible CIA crack connection
There is a whole branch of structural engineering called damage tolerance which deals with cracks. The certification process for new airplanes deals with it extensively. For example, we must assume that any airplane can have a .050" crack at any location. Such a crack is assumed to grow, and it might get quite long before it must be found. I'm talking inches in length, sometimes.
Equine Mammals Are Considerably Smaller
Just so you know, the crack is safe, and the shuttle will not be delayed because of it: http://www.cnn.com/2005/TECH/space/04/06/shuttle.r ollout/
I think the submitter needs to study the Columbia report and understand the Aerospace industry a lot more before trying to (and apparently succeeding at) alarming the /. crowd (which, quite frankly, isn't that hard to do).
First, while it was "pieces of foam" that caused the problem, it was decided that it was most likely a single suitcase-sized piece of foam hitting the leading-edge carbon/carbon that led to the eventual destruction of Columbia. The SOFI (spray-on foam insulation) process has been improved to reduce the number & size of voids in the SOFI. The maximum size of foam expected to fall off now is on the order of 1% of the size of the piece that doomed Columbia. Further, the bipod ramp foam has been eliminated in the redesign. Further, they've developed new techniques to inspect the SOFI so they can detect any anomalies. If they found something, which apparently they have, engineers can assess it and determine its severity. I'm not familiar with the specific issue, but depending on its sign & location, it was apparently deemed to not be a problem. Essentially, NASA is probably inspecting better now, so they are seeing more lumps. It doesn't mean that this isn't the best external tank ever built (it doesn't mean it is, either).
And in general, the whole SOFI system has extremely high visibility at NASA (I don't work there) and beyond (I do work there), and if any engineer thought it could be a safety issue, the launch would be delayed.
Not to mention, the tank wasn't "supposedly" redesigned; it was redesigned. Unless the submitter is suggesting that there was a massive conspiracy to deceive the public into pretending the shuttle tank was redesigned when it wasn't (but apparently not large enough to squelch any whistle-blowers), he should refrain from making those sorts of allegations.
The rest of his comment barely qualifies as idle speculation; the rescue crew is a last-resort, and NASA is not anticipating any problems. The idea of preparing a "rescue" craft was in direct response to Columbia when it was asked what NASA could do if they knew shuttle was doomed. If they detect a problem, NASA will assess and decide to either a) land at Kennedy/ Edwards as planned if there's nominal risk (I'd rate that at 95%), b) land in White Sands with a full crew if there's low to (I'm guessing) medium risk (let's call that 4.9%); c) launch a rescue mission and either ditch shuttle if they're sure it's doomed, or land at White Sands with a minimal crew if the think it might be doomed (I'd say 0.1%).
No, I'm not a rocket scientist. I'm a rocket engineer. And I find it sad that Slashdot chose to post this story when I bet there were other, fact-based submissions written by people more knowledgeable about the subject at hand.
After you were finished watching the Discovery show about lightning, did you happen to watch the video of the Challenger where it shows the burning gases venting from the side of the SRB just before the explosion? It's a kinda popular video. It was visible in rebroadcasts of the failed launch played on tv less than an hour after the explosion so you'll have to come up with a black helicopter theory about how "they" planned it all and made the "doctored" video available immediately after the explosion.
"The crack is about the size as a hair on the lens of a camera," NASA spokeswoman Eileen Hawley told reporters at NASA's Johnson Space Center. The crack was located just above the intertank door on the rear of the tank, opposite the orbiter, Hawley said.
It sounds like a small surface defect in the spray on insulation, not in the aluminum tank. Similar defects have probably happened before, but never made the headlines. Most likely the maximum hazard is that they will see a very small amount of ice growth at that site when propellant is loaded. This isn't even a significant threat because the crack is on the opposite side of the tank from the orbiter, so unless you've got some ice that can do fancier flying than Oswald's magic bullet there is no threat to launch.
What brought down Columbia was a large chunk of foam that was hand-applied when the tank was closed out. The hand-application process of the bipod ramp foam tends to leave large voids. That's what popped off and hit the wing. The ramps have been replaced with heaters to avoid ice formation at that location. (Ironically, the foam was put there in the first place to prevent ice from forming on that joint and hitting the orbiter.)
Disclaimer: I work for NASA, but any opinions are my own and haven't been approved by anybody. I'm just trying to inject a little sanity into this discussion...
The Challenger didn't "blow up", it disintegrated due to loss of attitude control at high speed. The orbiter experienced aerodynamic forces that greatly exceeded its structural design limits. Similar things happen when a high-performance jet aircraft loses attitude control at high speed.
Mea navis aericumbens anguillis abundat
but it is not the same shuttle that flew in the early 80s
You're right, it isn't. That one burned up on reentry a couple of years ago. The design, however, is fundamentally the same, modulo a few manufacturing refinements (TPS changes, etc) they came up with in the ones that flew in the mid 80s and beyond (and were all built in the late 70s/early 80s). Even Endeavour, the replacement for Challenger, is in large part made up of "structural spares" made during the original manufacturing run.
Of course they do pretty much tear down and completely overhaul each Orbiter between missions, which is another reason the dang things are so expensive to fly.
-- Alastair
Little is left unchanged on the Shuttle fleet except the airframe, which if designed right can almost last forever. The B-52 fleet has many airframes older than the parents of the people flying them for instance. None of the members of the shuttle fleet have that many launches on them, and with things like the entire engine being redesigned and rebuilt and the computers being massivly updated over the years the shuttles are only superficially the same craft as were first launched in the 80's.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
It's the 747 SP -- built for long range. It did indeed have a section removed from the middle, and more fuel tanks added. They're rare now that the newer 747s and other more modern airliners have comparable range (mostly due to beter engines). One is being converted into a flying astronomical observatory for NASA, though.
Oh no, what if someone breaks a nail?
The crack is not in the external tank. The crack is in the foam insulation surrounding the external tank. The lede in the Space.com story is wrong. Guess Slashdot readers and Slashdot staff can't be bothered to read more than one paragraph.
/. get paid to be this bad?
Do people at
-- Slashdot: When Public Access TV Says "No"
The A-10 was designed in the 70's, not the 50's. And it belongs to the Air Force, not the Army.
Note also that we built about 700 A-10's. Not four. Hell, there were more than four prototypes of the A-10. If we'd built shuttles by the hundreds, they wouldn't have this sort of problem either.
"I do not agree with what you say, but I will defend to the death your right to say it"
Russian commercial aircraft are flying older for the same reason that Boeing B-52(G)s designed in 1947 and updated throughout the 1950s are.
Just to pick nits: the active B-52 fleet is made up of B-52(H) models, which were built in 1960, making them a few years newer than the B-52(G). The "newer" H models have more efficient and more powerful engines than the G, and had numerous other improvements. The difference between the B-52(H) and B-52(G) is significant. The difference between the B-52(H) and B-52(A) from 1952 is HUGE!
AFAIK, the B-52(G), which were actively used in Gulf War I, are currently sitting in the desert to be chopped up. The B-52(H) are currently flying out of Barksdale, Louisiana, and Minot, North Dakota.
But back to your point, yeah, the B-52 dates back to the 1940s and aside from some modern computers and sensors, is still flying today with mostly 1950s technology.
Another old bird is the KC-135, the military version of the Boeing 707 4 engine jet (very similar to the Douglas DC-8). There are still a huge number of these birds flying in the US military for cargo, in-flight refueling, and intel/AWACS. The KC-135 is almost as old as the B-52 and was designed by the same group of engineers.
this is just plain wrong. The Mercury, Gemini and Apollo programs used only liquid fuel. The shuttle is the first and only "man-rated" solid booster in the US space program, and it required waiving many level 1 safety requirements, like having to be able to shut it off.
You are so deeply wrong here it isn't funny.
Mercury (after the first couple of missions), Gemini, and Apollo all placed their payloads in Earth orbit before they did anything else. Mercury and Gemini never left Earth orbit at all. Apollo, which did of course go to the moon (after leaving EO), required more thrust overall than any other space venture in history, because it had to boost everything necessary for reaching the Moon into EO. The Saturn V was the most powerful booster ever built, period. Even the modern Energiya can't match it.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
> How about the C-130 transport aircraft? It still uses fricking props!
You say that as if propellors are less desirable than jet propulsion for aircraft. (Of course, after typing out this long reply, I now see that you and I are largely making the same point, but why waste such a good explanation?) This is true only if we are talking about props powered by internal combustion engines--but the C-130 is powered by turbo-prop engines.
It is really a matter of different strengths and weaknesses. In the case of the C-130, a turbo-prop engine was "the best tool for the job". In a way, it is already a jet aircraft--except that the propulsion comes from the propellor rather than from the exhaust.
And in order to stay on topic... a random comment about STS
The most flawed aspect of the STS is the Solid Rocket Boosters(SRBs). The soviet shuttle system (Often called Buran, after the name of the first soviet orbiter) recognized this and did away with solid propellant altogether.
It was in my opinion a superior launch system and orbiter, even if it was a blatant rip-off. Buran also looked cooler too. Too bad it is now scrap. The one intact Buran shuttle that survived the fall of the soviet union did not survive the fall of the ceiling in the building it was housed in. So sad.
But eh. Yeah. Props still have their place.
— darco
Ah, but the Saturn V, unlike the N1, actually worked.
Every single launch of the N1 crashed and burned, one even fell back moments after liftoff and virtually destroyed the launchpad and surrounding area. All the N1 amounted to was a bunch of very loud explosions in remote parts of Russia.
Not to completely knock my comrades over the sea, I'm sure once the US moon program reached fruition the political nogoodniks backstabbed like crazy, which made it very difficult to get bugs out of the system. They decided to test fire engines prior to installation following the first launch failure, but that order was nixed from above - so they kept installing untested engines. Big bada boom.
Then they killed the N1 off in favor of the Buran, another Soviet program that never reached fruition. And the Buran, unlike the N1, was massively based off of leaked Shuttle documentation.
But hey, at least the Soyuz, Mir, and similarly small programs got their groove back.