What is it with Nasa, all their stuff always fails, I mean it's supposed to be going in to space and it's so temperamental it's unbelieveable, every launch I've heard of has had some sort of sensor failure. Seriously who designs these things?
STS-115 (Atlantis) space shuttle mission - "go" for launch
- Thread starter Berserker
- Start date
Whoever it was designed them 30 years ago, and they've done pretty well to get this far. It'll be a shame to see them retire in 2010, but it's getting more and more obvious why that's necessary.
Mind you, credit where credit is due. I bet all these same sorts of issues happened pre-Columbia and you never heard about them - they'd just get right on and launch regardless. It's damn frustrating for sure, but they're going for uber-safe now.
Mind you, credit where credit is due. I bet all these same sorts of issues happened pre-Columbia and you never heard about them - they'd just get right on and launch regardless. It's damn frustrating for sure, but they're going for uber-safe now.
Associate
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there has been delays due to sensor probs on many flights iirc, considering these things go through an almost total rebuild after every flight you would have thought that they would introduce new and better systems?
Soldato
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Energize said:
So Concorde was flirting with disaster 30 years on?
Somehow I think not. If it works, leave it.
Sensors break, can't make them more modern can you?
As for the shuttle, things are going to break. Not being used for 2 years doesn't help.
Flight certifying a new piece of hardware is an expensive and laborious process. In this case, it's not just the sensors, but also all the control hardware, interfaces etc.
The ECO sensors are tempremental as hell, but I doubt there's a great deal they can do about that short-term. They already replaced them all once because of a previous problem.
Flight certification is one reason they still use old IBM Thinkpads both on the shuttle and ISS. They actually got to the point a few years ago that they were having difficulty finding spares for them.
The ECO sensors are tempremental as hell, but I doubt there's a great deal they can do about that short-term. They already replaced them all once because of a previous problem.
Flight certification is one reason they still use old IBM Thinkpads both on the shuttle and ISS. They actually got to the point a few years ago that they were having difficulty finding spares for them.
Concorde Rules said:
It doesn't work though does it because it breaks often. Of course you can make electronics more modern otherwise we'd still be using pentium1. I certainly wouldn't risk peoples lives for money.
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Soldato
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Energize said:
Im guessing its something to do with the 2.5million moving parts on the craft
take a car....a couple of hundered moving parts at the very most, times this by a couple of million and a cars failure rate would approch that of a space shuttle, if not be worse. The fact its gone up and back so many times in such a complex machine is engineering genious.gurusan said:
dated but works for the most parts, its a complicated machine things will break. As I said some parts are better being old like CPU's as they handle space conditions a lot better. Then theres the cost factor and redesign and testing time.
Soldato
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gurusan said:
So what? The main technology works.
If you'd like to tell the scientists how to fix it then go ahead.
Concorde's Afterburners were the most temperental thing on her. Yet everything else worked. Why should they spend millions and millions on updating something that does exactly what it what designed to do.
You can't compare that to PCs. It has the power to do the job they are supposed to do.
AFAIK Concorde's 50 or so computers never failed (although I don't belive that
)
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some info from the wires: 
=========================================================
11:00 a.m., 09/08/06, Update: Launch delayed at least 24 hours due to ECO sensor failure
After a dramatic, down-to-the-wire debate, NASA's Mission Management Team called off the shuttle Atlantis' countdown today and delayed launch at least 24 hours because of concern about an apparently faulty low-level hydrogen fuel sensor in the ship's huge external tank.
"OK, Brent, we gave a lot of thought to the ECO sensor issue today and what we decided to do as a team is follow the launch commit criteria as writtem. And so we're going to detank this vehicle, come back in tomorrow, fill it back up and see how they behave and see if we can get more confidence in that system for tomorrow's attempt," Launch Director Mike Leinbach told commander Brent Jett and his five crewmates during a final "hold" at the T-minus nine-minute mark.
"So we appreciate you guys getting on board today," Leinbach said. "Tomorrow's weather should be just as good as it was today if not better. We all feel good about the attempt today, we didn't get there because of the ECO sensors."
"OK, Mike, we understand and we concur 100 percent," Jett replied from Atlantis' flight deck. "That whole plan was given a lot of thought by a lot of smart people, under not having the pressure of a vehicle on the pad. So it's the right thing to do."
The launch time Saturday is 11:14:55 a.m. and forecasters are predicting an 80 percent chance of good weather. At issue is whether Atlantis can be cleared for flight with three out of four hydrogen main engine cutoff - ECO - sensors operating. The sensors are part of a critical backup system intended to make sure the shuttle's main engines don't shut down early or run too long.
Problems with ECO sensors bedeviled NASA last year during the ramp up to the first post-Columbia mission, prompting one scrub and intense analysis. After the flight, engineers traced the problem to a suspect connection betweem sesors and electrical cables in a specific batch of ECO sensors manufactured in the late 1990s.
The sensors in a tank used by the shuttle Discovery last month were replaced with a set thought to be fault free and those sensors worked as expected. The sensors in Atlantis' tank also were replaced after detailed inspections identified the best available sensors.
It is not yet clear whether the problem seen today, when hydrogen ECO sensor No. 3 "failed wet," involved the sensor, its wiring or an avionics box aboard the shuttle that reformats and routes the data to flight computers.
Twenty four propellant sensors are used in the shuttle's external tank, 12 each in the oxygen and hydrogen sections. Eight are used in each tank to measure the amount of propellant present before launch. Four ECO sensors in each tank are used in flight as part of a backup system intended to make sure the ship's engines don't shut down too early, resulting in an abort, or run too long, draining the tank dry with potentially catastrophic results.
NASA's original launch commit criteria required three operational ECO sensors for a countdown to proceed. But in the wake of the 1986 Challenger disaster, the LCC was amended to four-of-four because of concerns two sensors could be knocked out by a single failure in an upstream electronic black box known as a multiplexer-demultiplexer. The single-point failure later was corrected, but the four-of-four launch rule remained on the books.
Because of ECO sensor problems going into me first post-Columbia mission, NASA managers ultimately developed an "exception" to the four-of-four rule that would permit a launch if A) a hydrogen sensor failed wet; and B) engineers could show the problem didn't originate in the multiplexer-demultiplexer avionics system.
As originally written, the flight rule exception called for standing down a day. A second launch try could then be made depending on an analysis of the way the sensor failed and how it behaved during a second fueling. With one sensor failed wet, two more ECO sensors would have to fail wet to pose the threat of running the tank dry.
Many observers were surprised NASA's Mission Management Team held open the option of launching today for so long. The flight rule was intended to give engineers a way to press ahead with a launch in the case of a single sensor failure, but only after taking time to make a thorough analysis, away from the pressure of a launch countdown.
If the shuttle doesn't get off the ground Saturday, the long-awaited and oft-delayed mission almost certainly will slip to late this month - or next - because of a daylight launch constraint and conflict with a Russian mission to rotate crews on the international space station.
A launch past Saturday is not believed to be an option because the shuttle would still be in orbit when the Russians launch the Soyuz TMA-9 spacecraft Sept. 18 and that is a violation of existing joint agreements.
If the shuttle doesn't get off Saturday, NASA presumably could launch after a Soyuz carrying the returning station crew lands Sept. 28. But that would require managers to relax a current requirement to launch in daylight for photo documentation of the shuttle's external tank and heat shield.
The next lighted launch opportunity after Saturday is Oct. 26.
=========================================================
11:00 a.m., 09/08/06, Update: Launch delayed at least 24 hours due to ECO sensor failure
After a dramatic, down-to-the-wire debate, NASA's Mission Management Team called off the shuttle Atlantis' countdown today and delayed launch at least 24 hours because of concern about an apparently faulty low-level hydrogen fuel sensor in the ship's huge external tank.
"OK, Brent, we gave a lot of thought to the ECO sensor issue today and what we decided to do as a team is follow the launch commit criteria as writtem. And so we're going to detank this vehicle, come back in tomorrow, fill it back up and see how they behave and see if we can get more confidence in that system for tomorrow's attempt," Launch Director Mike Leinbach told commander Brent Jett and his five crewmates during a final "hold" at the T-minus nine-minute mark.
"So we appreciate you guys getting on board today," Leinbach said. "Tomorrow's weather should be just as good as it was today if not better. We all feel good about the attempt today, we didn't get there because of the ECO sensors."
"OK, Mike, we understand and we concur 100 percent," Jett replied from Atlantis' flight deck. "That whole plan was given a lot of thought by a lot of smart people, under not having the pressure of a vehicle on the pad. So it's the right thing to do."
The launch time Saturday is 11:14:55 a.m. and forecasters are predicting an 80 percent chance of good weather. At issue is whether Atlantis can be cleared for flight with three out of four hydrogen main engine cutoff - ECO - sensors operating. The sensors are part of a critical backup system intended to make sure the shuttle's main engines don't shut down early or run too long.
Problems with ECO sensors bedeviled NASA last year during the ramp up to the first post-Columbia mission, prompting one scrub and intense analysis. After the flight, engineers traced the problem to a suspect connection betweem sesors and electrical cables in a specific batch of ECO sensors manufactured in the late 1990s.
The sensors in a tank used by the shuttle Discovery last month were replaced with a set thought to be fault free and those sensors worked as expected. The sensors in Atlantis' tank also were replaced after detailed inspections identified the best available sensors.
It is not yet clear whether the problem seen today, when hydrogen ECO sensor No. 3 "failed wet," involved the sensor, its wiring or an avionics box aboard the shuttle that reformats and routes the data to flight computers.
Twenty four propellant sensors are used in the shuttle's external tank, 12 each in the oxygen and hydrogen sections. Eight are used in each tank to measure the amount of propellant present before launch. Four ECO sensors in each tank are used in flight as part of a backup system intended to make sure the ship's engines don't shut down too early, resulting in an abort, or run too long, draining the tank dry with potentially catastrophic results.
NASA's original launch commit criteria required three operational ECO sensors for a countdown to proceed. But in the wake of the 1986 Challenger disaster, the LCC was amended to four-of-four because of concerns two sensors could be knocked out by a single failure in an upstream electronic black box known as a multiplexer-demultiplexer. The single-point failure later was corrected, but the four-of-four launch rule remained on the books.
Because of ECO sensor problems going into me first post-Columbia mission, NASA managers ultimately developed an "exception" to the four-of-four rule that would permit a launch if A) a hydrogen sensor failed wet; and B) engineers could show the problem didn't originate in the multiplexer-demultiplexer avionics system.
As originally written, the flight rule exception called for standing down a day. A second launch try could then be made depending on an analysis of the way the sensor failed and how it behaved during a second fueling. With one sensor failed wet, two more ECO sensors would have to fail wet to pose the threat of running the tank dry.
Many observers were surprised NASA's Mission Management Team held open the option of launching today for so long. The flight rule was intended to give engineers a way to press ahead with a launch in the case of a single sensor failure, but only after taking time to make a thorough analysis, away from the pressure of a launch countdown.
If the shuttle doesn't get off the ground Saturday, the long-awaited and oft-delayed mission almost certainly will slip to late this month - or next - because of a daylight launch constraint and conflict with a Russian mission to rotate crews on the international space station.
A launch past Saturday is not believed to be an option because the shuttle would still be in orbit when the Russians launch the Soyuz TMA-9 spacecraft Sept. 18 and that is a violation of existing joint agreements.
If the shuttle doesn't get off Saturday, NASA presumably could launch after a Soyuz carrying the returning station crew lands Sept. 28. But that would require managers to relax a current requirement to launch in daylight for photo documentation of the shuttle's external tank and heat shield.
The next lighted launch opportunity after Saturday is Oct. 26.
They say they could launch safely with no ECO sensors at all - the ECO sensors are a backup of a backup. However, in the event all the systems failed, the engines would likely rip themselves apart, and take bits of the shuttle with it, which would certainly be a 'bad day'. NASA actually had a few engines run dry and do exactly this during testing.
Actually, this is good for me. It means that if they launch tomorrow and complete the mission, at least one of the spacewalks will definitely be while I'm working at home, which might not have been the case previously.
Actually, this is good for me. It means that if they launch tomorrow and complete the mission, at least one of the spacewalks will definitely be while I'm working at home, which might not have been the case previously.