6 ms·

Cluster (spacecraft)

29 points by PiersonBro 13y ago

_jmar777 13y ago
Sounds like it was a real cluster * * * *.
hdevalence 13y ago
This is the video of the launch, or, "What integer overflow looks like": https://www.youtube.com/watch?v=kYUrqdUyEpI https://www.youtube.com/watch?v=kYUrqdUyEpI
spuz 13y ago
Though there are many factors leading up to the failure listed in the article, I think the most serious one was not testing the system under the expected flight conditions. It seems like such a big oversight that I wouldn't be surprised if there were other bugs lurking in the system that had also gone undetected.
deleted 13y ago
[deleted]
alexsb92 13y ago
Maybe someone more knowledgeable about these things can answer this for me: when they say that this resulted in the loss of $370 million, is that number the entire mission cost or simply the actual rocket plus Cluster cost? I imagine the r&d cost far outweighs the cost of the actual build. I've been wondering at the same time why we don't send another one or two rovers to mars based on the design of curiosity seeing how it worked, as how expensive would the entire build be to replicate considering there's no more r&d costs?
- stackcollision 13y ago
  I think it is physical materiel and fuel costs. The R&D efforts leading up to the launch were certainly not a waste, as the Ariane V flew again after the accident, so it doesn't make sense to include them in the loss.
- akiselev 13y ago
  Modern space programs operate on a skewed risk tolerance mostly for public relations purposes. Given a billion dollar program with a $250 million final build and launch cost, NASA and ESA will chose to spend $750 million on R&D and launch one mission with a 95% success chance instead of $500 million on R&D and two missions with a 80-90% success chance (money spent on R&D has rapid diminishing returns on the success rate of satellites, whether you're talking about CubeSats or billion dollar satellite arrays, and two launches at 80% has a 96% success chance). NASA knows that most projects (Mars Science Lab excluded) can be done such that the budget pays for two launches instead of one by spending money on cheaper components (a single CPU made specifically for high radiation environments is like $1mil+) but when it comes to public perception, 2 failed launches sounds better than 3 or 4 (despite the fact that the latter would mean 6-7 successful launches versus 3-4 for the former). The $370 million was probably the cost of the four satellites and the rocket + operations. It might include R&D but not most of the scientific operations part of the grant (there is tons of science to do before and after a scientific mission like this).
  - mturmon 13y ago
    You're making some broad-brush proclamations here that are wrong. I think you have a point regarding the risk tolerance of some NASA missions, but you're exaggerating too much, and your comment can't be taken seriously as a result. I don't want to thoroughly engage all the problems with your comment, but I'll point out two: (1) Launching two spacecraft is not a cure for poor system reliability. Systems fail after launch for all kinds of reasons; a 1-in-2 launch success rate and 2 launches does not guarantee a successful mission. You can't build systems that are half reliable and half not. (2) Some things really have to work on the first try: Earth and sun-observing systems that need data continuity with failing earlier systems, planetary missions with narrow launch windows, systems with standing armies of on-ground analysis personnel who can't be put on hold while a replacement is built and launched.
    - akiselev 13y ago
      1) I'm not talking about stripping the budget willy-nilly but relaxing the risk-tolerance that goes into making the calculations for the reliability budget across the board. A trivial example from my own experience is in working on a Cubesat thermal system. There were a lot of trade offs that we had to make like whether to use cheap thermal tape or use some expensive quartz reflective panels or whether to just slap a heat sink on something or use a peltier cooler. Each trade off could drastically change the cost of the final build and the cost of R&D time and equipment. For a Cubesat, the added up differences wouldn't cover the cost of a second launch but I would expect there to be major trade offs to be made that wouldn't totally compromise the mission in larger projects. 2) I fully agree, and there are many missions that are just so important that we should strive for success on the first try (MSL, some extremely better telescope like NuStar, and probably the satellites in this article), but NASA's/ESA's budget is much bigger than just those missions and I would argue many of them could have afforded second launches without drastically compromising reliability (i.e. without becoming half reliable and half not as you say)
quanticle 13y ago
Can someone tell me why this article spends 90% of its wordcount talking about the rocket used to launch the spacecraft rather than the spacecraft itself?
- gojomo 13y ago
  You should probably write a letter to the editor of Wikipedia with your question/complaint, and perhaps threaten to cancel your subscription if their writing doesn't improve to cover what you think it should cover.
- vilhelm_s 13y ago
  Currently, "Ariane 5 Flight 501" redirects to this article. There is a category for launch failures (http://en.wikipedia.org/wiki/Category:Satellite_launch_failures http://en.wikipedia.org/wiki/Category:Satellite_launch_failu...), and looking at that I guess the Wikipedia convention is to name launch failure articles after the satellite that would have been launched.
  - maaku 13y ago
    That's industry tradition. It's not common to number or name launches, but rather to refer to the primary payload, e.g. “The MSL launch”. EDIT: I'm sure that the launch provider has some naming scheme referencing the rocket itself, but usage of that is almost universally confined to internal communications. Human spaceflight is perhaps the exception (STS-125, not Hubble Servicing Mission #4).
bttf 13y ago
And if they used TDD, this wouldn't have happened.
teeja 13y ago
That one's bad enough, but my favorite is the $420M "Glory" satellite that fell into the Pacific ... after the payload faring separation failed ... just like it did for the previous, Orbiting Carbon Observatory launch. https://en.wikipedia.org/wiki/Glory_%28spacecraft%29 https://en.wikipedia.org/wiki/Glory_%28spacecraft%29

29 points by PiersonBro 13y ago

Sounds like it was a real cluster * * * *.

This is the video of the launch, or, "What integer overflow looks like": https://www.youtube.com/watch?v=kYUrqdUyEpI https://www.youtube.com/watch?v=kYUrqdUyEpI

spuz 13y ago

Though there are many factors leading up to the failure listed in the article, I think the most serious one was not testing the system under the expected flight conditions. It seems like such a big oversight that I wouldn't be surprised if there were other bugs lurking in the system that had also gone undetected.

deleted 13y ago

[deleted]

alexsb92 13y ago

Maybe someone more knowledgeable about these things can answer this for me: when they say that this resulted in the loss of $370 million, is that number the entire mission cost or simply the actual rocket plus Cluster cost? I imagine the r&d cost far outweighs the cost of the actual build. I've been wondering at the same time why we don't send another one or two rovers to mars based on the design of curiosity seeing how it worked, as how expensive would the entire build be to replicate considering there's no more r&d costs?

stackcollision 13y ago
I think it is physical materiel and fuel costs. The R&D efforts leading up to the launch were certainly not a waste, as the Ariane V flew again after the accident, so it doesn't make sense to include them in the loss.
akiselev 13y ago
Modern space programs operate on a skewed risk tolerance mostly for public relations purposes. Given a billion dollar program with a $250 million final build and launch cost, NASA and ESA will chose to spend $750 million on R&D and launch one mission with a 95% success chance instead of $500 million on R&D and two missions with a 80-90% success chance (money spent on R&D has rapid diminishing returns on the success rate of satellites, whether you're talking about CubeSats or billion dollar satellite arrays, and two launches at 80% has a 96% success chance). NASA knows that most projects (Mars Science Lab excluded) can be done such that the budget pays for two launches instead of one by spending money on cheaper components (a single CPU made specifically for high radiation environments is like $1mil+) but when it comes to public perception, 2 failed launches sounds better than 3 or 4 (despite the fact that the latter would mean 6-7 successful launches versus 3-4 for the former). The $370 million was probably the cost of the four satellites and the rocket + operations. It might include R&D but not most of the scientific operations part of the grant (there is tons of science to do before and after a scientific mission like this).
- mturmon 13y ago
  You're making some broad-brush proclamations here that are wrong. I think you have a point regarding the risk tolerance of some NASA missions, but you're exaggerating too much, and your comment can't be taken seriously as a result. I don't want to thoroughly engage all the problems with your comment, but I'll point out two: (1) Launching two spacecraft is not a cure for poor system reliability. Systems fail after launch for all kinds of reasons; a 1-in-2 launch success rate and 2 launches does not guarantee a successful mission. You can't build systems that are half reliable and half not. (2) Some things really have to work on the first try: Earth and sun-observing systems that need data continuity with failing earlier systems, planetary missions with narrow launch windows, systems with standing armies of on-ground analysis personnel who can't be put on hold while a replacement is built and launched.
  - akiselev 13y ago
    1) I'm not talking about stripping the budget willy-nilly but relaxing the risk-tolerance that goes into making the calculations for the reliability budget across the board. A trivial example from my own experience is in working on a Cubesat thermal system. There were a lot of trade offs that we had to make like whether to use cheap thermal tape or use some expensive quartz reflective panels or whether to just slap a heat sink on something or use a peltier cooler. Each trade off could drastically change the cost of the final build and the cost of R&D time and equipment. For a Cubesat, the added up differences wouldn't cover the cost of a second launch but I would expect there to be major trade offs to be made that wouldn't totally compromise the mission in larger projects. 2) I fully agree, and there are many missions that are just so important that we should strive for success on the first try (MSL, some extremely better telescope like NuStar, and probably the satellites in this article), but NASA's/ESA's budget is much bigger than just those missions and I would argue many of them could have afforded second launches without drastically compromising reliability (i.e. without becoming half reliable and half not as you say)

quanticle 13y ago

Can someone tell me why this article spends 90% of its wordcount talking about the rocket used to launch the spacecraft rather than the spacecraft itself?

gojomo 13y ago
You should probably write a letter to the editor of Wikipedia with your question/complaint, and perhaps threaten to cancel your subscription if their writing doesn't improve to cover what you think it should cover.
vilhelm_s 13y ago
Currently, "Ariane 5 Flight 501" redirects to this article. There is a category for launch failures (http://en.wikipedia.org/wiki/Category:Satellite_launch_failures http://en.wikipedia.org/wiki/Category:Satellite_launch_failu...), and looking at that I guess the Wikipedia convention is to name launch failure articles after the satellite that would have been launched.
- maaku 13y ago
  That's industry tradition. It's not common to number or name launches, but rather to refer to the primary payload, e.g. “The MSL launch”. EDIT: I'm sure that the launch provider has some naming scheme referencing the rocket itself, but usage of that is almost universally confined to internal communications. Human spaceflight is perhaps the exception (STS-125, not Hubble Servicing Mission #4).

bttf 13y ago

And if they used TDD, this wouldn't have happened.

teeja 13y ago

That one's bad enough, but my favorite is the $420M "Glory" satellite that fell into the Pacific ... after the payload faring separation failed ... just like it did for the previous, Orbiting Carbon Observatory launch. https://en.wikipedia.org/wiki/Glory_%28spacecraft%29 https://en.wikipedia.org/wiki/Glory_%28spacecraft%29