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Shuttles Grounded Once Again
PipianJ writes "After discovering that the piece of the shuttle that fell off mysteriously, not actually striking it, (as reported earlier) was a piece of foam insulation not unlike the piece that ended up in the destruction of Columbia, Yahoo News reports that NASA has once again grounded the shuttle fleet."
The point is, now that we're looking intensely for problems in this area, we're going to find them. We're looking with eyes, cameras, satellites, lasers, sensors, robotic arms - all with unprecedented scrutiny. What do we expect to find? The shuttles are the most complicated pieces of machinery ever built, designed to launch into space with a controlled explosion, and then return to earth. Regardless of whether some here think the shuttle is junk, whether it's unnecessary, whether Air Force jocks doomed the program for the beginning, whether manned spaceflight is sentimental tripe, etc., the fact remains that flying something like the shuttle is a risky endeavor.
It's all about smart management of risk. Eliminating risk, especially for something like the shuttle, is impossible. This focus on debris falling from the shuttle is nothing more than a reactionary CYA tactic in the midst of a media circus in case something else like this were to happen again. Doing get me wrong: it's wise to consider the problem, to attempt to prevent it, and to ensure there is not undue exposure. But that exposure cannot be eliminated, and this intense focus on debris in particular beyond anything else, even in light of Columbia, is unwarranted.
NASA is operating in panic mode: one more catastrophic shuttle failure, and that's the end of the shuttle program, and essentially the practical end of the ISS and a lot of scientific research to boot. If you're paralyzed with fear, you're, well...paralyzed.
This New York Times article, which I posted in the previous article on this, sums up the situation quite nicely, for those who may have missed it.
Notable:
"How do you distinguish - discriminate - between damage which is critical and damage which is inconsequential?" asked Dr. David Wolf, an astronaut who spent four months aboard the Russian space station Mir. "We could be faced with very difficult decisions, in part because of all this additional information that we will be presented with."
"...the harder they look, they'll find more things."
"There is risk in anything you do."
July 27, 2005
Intense Hunt for Signs of Damage Could Raise Problems of Its Own
By JOHN SCHWARTZ
CAPE CANAVERAL, Fla., July 26 - Now that the Discovery is in orbit, the examination begins. Its 12½-day mission will be the most photographed in the history of the shuttle program, with all eyes on the craft to see if it suffered the kind of damage from blastoff debris that brought down the Columbia in February 2003.
There were cameras on the launching pad, cameras aloft on planes monitoring the ascent, cameras on the shuttle checking for missing foam on the external fuel tank, and a camera on the tank itself. One camera caught a mysterious object falling from the shuttle at liftoff; radar detected another, about two minutes into the flight. Cameras aboard the shuttle and the International Space Station will monitor the Discovery until the end of its mission.
But all this inspection may be a mixed blessing. The more NASA looks for damage, engineers an
I guess you've never heard of an embedded system.
Those can't ship with bugs. Try applying a patch to several hundred 512 byte micros that are controlling the charging systems on the shock paddles in hospitals.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
The Parent poster is cracking a joke, referring to the science fiction show "Stargate: Atlantis". There is no such thing as a "Zero Point Module" yet.
Nice idea, but it won't work. Ice formation on the tank has nothing to do with it. The trouble with hand-laid foam insulation(which is what this was) is that large air pockets can form during the forming process. These air pockets are at atmospheric pressure (14.7 psi). As the craft climbs higher into the atmosphere, the surrounding air pressure drops, causing that pocket to expand. Eventually the pocket can pop like a balloon, knocking off a chunk of foam. Were the tank painted, the paint would just come off along with the rest of the piece.
The mission continues. Likely, if a problem surfaces, Atlantis would still be sent up after them. There's no sense in bringing down the orbiter until the assessments they already had planned for this mission can be completed. Right now, the shuttle does not appear to be damaged; it was a close call. Once Discovery lands, though, that's it until the tank's fixed.
so, Thom Patterson - CNN reported last night that it was a 1.5" piece of tile. MARCIA DUNN, AP Aerospace Writer - on the yahoo! news - says that it's a "sizable chunk of foam insulation -- the very thing that doomed Columbia" - but then later says that it was indeed a 1.5" piece of tile while in the latest report from yahoo! it's simply "a large piece of foam insulation broke." interesting to see this evolve. at least it's not being sensationalized...
In the mid-to-late 1980s there was a USAF program called NASP--National Aero-Space Plane. It was supposed to do exactly what you're describing.
NASP was eventually scrapped as "unworkable", and its successor project -- IIRC, the X-33 -- did not fare much better, even though it was actually built.
The short answer for why we haven't done it is "fuel is heavy." I'm not qualified to give the long answer, but a straight shot right into the atmosphere really is the cheapest way to get a given weight into orbit.
And, btw, the Space Shuttle *IS* hydrogen powered. The two solid-fuel boosters aren't, but that big foam-covered tank is just a shell carrying two parts H to one part O, which is what burns out of the shuttle's main engines.
Not really.
The X-33 was over-budget, late, and suffering major development problems. The performance was getting worse and worse. And then you would have had to hope that Lockheed-Martin was willing to put up their portion of the funds to build the production booster.....
And, at the same time, Iridium was bankrupt, "Dark Fiber" was eating into comsat requirements, etc.
And worst of all the Skunk Works had said, "Hey, we've been building all kinds of classified stuff all these years. I know that nobody in the public field can make a multi-lobed composite hydrogen tank, but we can pull one off, winkwinknudgenudge" So when it was shown that they couldn't, people lost faith. Especially because the only actually novel, testable parts of it was that multi-lobed composite hydrogen tank and the linear aerospike... everything else wasn't going to be getting a proper workout because it wasn't going to have enough speed to really properly test the metal skinned TPS or much else.
The problem was the X-33 was the riskiest design of the three contenders. So it was mostly doomed from the start....
No, they'll probably figure out how to dust off the shuttle yet again and fly it. Remember, it's just the PAL ramp that's the problem, so they might just be able to change it to using a metal cover.
Gentoo Sucks
I'm going to treat this as if you were serious...
Liquid hydrogen (the stuff in the big, brown tank, along with liquid oxygen) has a boiling temperature of about -434 degrees fahrenheit.
The launch site is next to the ocean and bounded by swamps and rivers. Humidity at the launch site is quite high. The surface of the external tank, if exposed to the atmosphere without the foam, would develop a very thick layer of ice - a material with considerably higher density than foam.
Now, which would you rather flake off of your orbiter during climbout: ice, or foam?
The foam in question insulates the disposable fuel tank so ice doesn't form on it. It does not reach orbit and is not part of the shuttle. The problem with the previous shuttle was that the foam hit the shuttle tiles as it fell off. Since this foam did not hit the shuttle, there is no problem with it.
Infuriate left and right
Northrop Grumman and Boeing are getting prepped for the CEV, the successor to the space shuttle. According to this page, they are expecting flight demos in 2008 and manned CEV flight by 2014. If Griffin (the new NASA administrator) has his way, this will be fast-tracked to 2010. Exciting times are ahead...
Slashdot's first reaction to VMware
How about switching back to the older foam that shead less. NASA switched to an "envrionmentally friendly" foam a few years back, even though they have an exemption...
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
the root of Moores' Law states, fundamentally, that the more you use a technology, the better it gets.
Actually, Moore's law doesn't even directly talk about performance at all.
It is specific to integrated circuits and says that the complexity will double roughly every two years.
Complexity roughly corresponds to number of transistors which certainly roughly corresponds to performance.
See Wikipedia.
Actually, if ice were the problem they would ignore it - they typically do not bother to insulate LOX tanks, for example, because they form an ice layer that is a very effective insulator (the ice falls off during launch, but in a normal rocket nothing is below the tank to hit!).
The problem with LH is that it condenses oxygen from the atmosphere onto it. That does two really bad things - first, you now have lox all over the place turning everything around it into a high explosive (pratically any porous substance, like concrete or asphalt, becomes a high explosive when saturated with LOX), and this is not a good thing to have around when lighting up a rocket. Second, condensing the LOX adds a lot of energy into the LH, boiling it, possibly raising the pressure enough to rupture the tank - KABOOM! (Remember that LOX sitting around outside the tank? Great stuff!)
Even if the LH tank doesn't rupture, you would never get the tank full enough to fly...
while (sig==sig) sig=!sig;
Astronauts are on government pay scales GS-11 thru GS-14.
The lowest step of GS-11 is $45K per year, the highest step of GS-14 is $99K per year.
Another way to look at it is that they do it in spite of the middling bucks, because that's the sort of person they are.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
You'd be suprised
thermal problems are one of the most difficult on a space mission. solar radiation, cryogenic fuels, and of course, the vacuum of space make keeping all your parts in a 20 or 30 degree range a huge pain in the ass.
foam is the simplest option, as its totally passive. what happens if your giant foam net doesn't detatch from the shuttle properly and rips off a section of the shuttle underbody during launch?
I just found the box to change my sig. Um.... [timeless witticism].
Example: Airbus' fly-by-wire system, designed to override a pilot when a dangerous decision was made, erroniously concluded a forest was a runway after a very low pass was made over it. Deciding the speed was too high, it cut the engines. Both pilots and something like 18 journalists were killed. Airbus blamed the pilots - a safe decision as the pilots couldn't answer back, being dead and all, and the only one they could have made. Blaming the computer could have put them out of business.
ALMOST an example: Electromagnetic interference, caused by badly-screened and improperly-earthed electronics throughout Manchester, caused the computers operating Manchester Ringway's Radar system to shut down. Given that it is one of Britain's busiest international airports and that temperature inversions will often cause some really nasty orange/yellow smog, that could have caused more than a delay.
New York's phone system shut down, one time, due to a digital exchange propogating a negative number of users through that area. As routing worked by picking the least-congested path, the exchange suffered the telephony version of a Slashdot Effect. This included an effective shutdown of 911 services. It is unclear how many died as a result, if any, but the potential for a real disaster was there.
Many of the cascading power blackouts that have occured since the 1950s (there have been four or five in the US, and at least a couple in the UK) have been due to bugs in the design of the response systems. It is arguable as to whether this is quite the same as a system crash, but the effect was the same. It's not clear how many died from those, either, but the mid 100s to low 1000s would not be unreasonable.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Considering it's been 360 years since the last English Civil war and 140 years since the last American Civil war, I'd be inclined to say that the American system is fairly stable, but doesn't look set to be breaking any records quite yet. I come from Australia where the last thing that looked like it could have become a civil war (but didn't) happend in Ballarat 160 years ago and so even that beats America's current record.
When Argumentum ad Hominem falls short, try Argumentum ad Matrem
>You're limited in how much and what size by doing that. In case you all haven't noticed. The orbiter plus the solid rocket boosters form a powered triangle. A more stable formation for carrying a big load, say a telescope.
You're kidding, right, AC? The Shuttles can carry at most 28 tons of cargo. Saturn V could lob 118 into LEO. Proton can boost almost as much as Shuttle, for far less money, including a series of integrated space station components (Zarya, Zvezda, Mir baseblock). Maybe the trunnion pins were great for launching Hubble, but that is the exception. Your "triangle" thing doesn't make sense, inline thrust structure is more efficient, less mechanically complex and makes trajectory calculation simpler.
>And siting on top of a roman candle is safe?
Yes, comparatively. For manned flight, a rocket under the crew is far safer than having components next to them. Launch escape towers are safe, accurate tools for keeping crews safe from an exploding "candle". There is footage online of a Soyuz capsule popping off the rocket right above the pad, the rocket failed but the crew lived. The same can't be said for low-altitude launch problems with Shuttle.
Capsules, rockets and tugs for station components make sense. Buck Rogers spaceplanes don't.
gigantino.tv - Heavy but weighs nothing.
In fact, the EPA actually offered a waiver for NASA/Space Shuttle Program.
You can see a letter from NASA in response to the EPA firmly stating they *need* to continue to use CFCs for the Space Shuttle Program, specifically.
http://www.nasa.gov/pdf/45329main_hcfc4_001.pdf
Check this link. There's a plenty of cool pictures available for free, just not on a CD. (hey, that rhymes :-)
... Fuel costs are a low % of the total cost of each launch. So optimizing things to reduce fuel costs is almost a waste of time.
The goal was to build something so you could just refuel it each time you want to send it up thus saving a lot of $ but a large % of the ship is not reusable and they have to inspect / disassemble the rest of the thing each flight which is why it's so expensive. They should have build a ship that can do low temp reentry and can do horizontal takeoff and landing not some sort of rocket where you have to rebuild build 90% of it for each launch.
Much has been made of the two types of foam, but it's a non-issue in reality.