Cluster (spacecraft)

http://en.wikipedia.org/wiki/Cluster_(spacecraft)

by PiersonBro • 13 years ago

29 17 13 years ago

en.wikipedia.org

_jmar777• 13 years ago

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

hdevalence• 13 years ago

This is the video of the launch, or, "What integer overflow looks like":

https://www.youtube.com/watch?v=kYUrqdUyEpI

spuz• 13 years 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.

alexsb92• 13 years 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• 13 years 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.

akiselev3• 13 years 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).

mturmon3• 13 years 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.

quanticle• 13 years 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• 13 years 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• 13 years 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_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• 13 years 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• 13 years ago

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

teeja• 13 years 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

Cluster (spacecraft)

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