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Uprated "10-ton" Ariane 5 Fails
Soft writes "The latest version of the European Ariane 5 booster ("ESC-A") has failed on its first launch. Liftoff was good up to booster separation but the core stage shut down one minute afterwards or so. The rocket was supposed to lift ten metric tons (22,000 lb) to geostationary transfer orbit, versus 6.7 for the previous Ariane 5G (and 5 and 5.3 for the latest Atlas 5 and Delta 4). Arianespace planned to retire its other launchers (Ariane 4, Ariane 5G) in favor of Ariane 5 ESC-A. Next launch, of space probe Rosetta, was due in mid-January."
There were two satellites on board, a Hotbird TM7 spacecraft, which would have served TV and music. It was supposed to replace Hotbird 3 at 13.0EL, though now that obviouosly wont happen.
Also the Stentor spacecraft was on board, this satellite was equiped with six Ku transponders, and was destined for 11.0WL.
The Doormat
If you're not outraged, then you're not paying attention.
... was due to re-used software code from the Ariane 4 program, except that some values that the soft was supposed to handle were WAY bigger than during the (near perfect, by the way) Ariane 4 program. It was a plain overflow issue... The worst comes: the issue was known and documented, but somehow forgot during the upgrade from V4 to V5...
;))
Anyway, it's pretty sad (AND NOT DUE TO THE USE OF THE METRIC SYSTEM, for you US fellows
System.out.println("coucou");
In europe, most of the major aerospace companies are actually government owned, and there arent very many of them as a result.
-
There's a nice table here (middle of page) showing some raw numbers between 1957 and 1998. Basically, 3022 of 3092 (97%) total launches were successful.
Actually, all of our (American) unmanned rockets are launched on Lockheed and Boeing vehicles. The government owns the launch sites but I seem to recall recently that even that has changed with one of the pads at KSC being purchased by someone. The space shuttle is maintained by a Boeing/Lockheed conglomerate under contract with NASA. And many of our space probes are built at least jointly in cooperation with industry. NASA is the beurocracy (don't mean that negatively) who pays for and manages these programs.
"It takes considerable knowledge just to realize the extent of your own ignorance." - Thomas Sowell
Can you back up that claim that the Russian's have the best success rate in space? Take a look here http://www.space.com/news/proton_nasa_991028.html . According to NASA russian Proton rocket has success rate of 92% and unless I am missing something can put 45,000 pounds (20ton) compare to oh 10ton for Arian into orbit. http://www.space.com/news/spacehistory/proton_hist ory_000707.html
On the pad? Try again.
bash$
Everyone writing software for a living should read the Ariane 5 Failure Report: Ariane5.html
and the description of the Mars Pathfinder "reset" problem: pathfinder.html
Another good study to read covers the loss of the Mars Polar Lander: marsreports.html
"Yes, I'm glad we got some peaceful dividends from ICBM work, but this could have been achieved more cheaply,"
Um... the US space program has had little if anything in common with our ICBM program since the Gemini program at the latest. Sure, the Redstone and the original Atlas were originally made to lob nukes, but once we were launching something bigger than a Mercury capsule, our ICBM boosters just didn't cut it. Unlike the Soviets, we could make nukes that were small enough to be launched on rockets too small for a manned space program (where do you think their head start in the space race came from?).
I mean, come on, unless you're going to nuke a target on the Moon, what use is a Saturn V in a nuclear war? Sure, it could be used to throw kilotons of conventional explosives half-way around the world (think "Skylab made of C-4"), but...
The insurers can. I work for a company that operates satellites, and the lowest insurance costs are for Russian launchers, because of their proven success rates. BTW, the insurers are British.
"russian Proton rocket has success rate of 92% and unless I am missing something can put 45,000 pounds (20ton) compare to oh 10ton for Arian into orbit."
What you are missing: LEO != geostationary.
NASA does not manage the ELV (expendable launch vehicle) programs, such as Atlas, Delta and Pegasus. These are run and funded by private companies. NASA's involvement is limited to contracting for launch services, just like any other customer, and providing limited launch support from its ground and space network of tracking stations/satellites.
Mea navis aericumbens anguillis abundat
There was nothing wrong with the software, as long as it was being used on an Ariane-4. The problem was that the software was not properly modified and tested before being used on Ariane-5. The flight profile of the Ariane-5 was significantly different than the Ariane-4, which caused the software to fail. Think of it as reusing the engine controller from a 2.0 liter engine on a supercharged 3.0 liter engine, without revisiting the assumptions made about engine characteristics in the original software.
Mea navis aericumbens anguillis abundat
In other words, one of the reasons that amatuer development is so limited is not simply cost. It's large space programs saying things like "we have experience and the finances to absorb failure, so that is why we reccomend you stay out of it. "the stars are not for man" kind of philosophy, if you get my drift. I'm not saying that it's great that something blew up, I'm saying that the it's bunk to say things like "leave this to the pros. space exploration is too complicated for civilians." or haven't you noticed, that instead of when airplanes, televisions, and computers were in the early stage of innovation, there aren't many private backers of orbital ventures. Is that a coincidence? BTW, I could really do without commenting on the moderation and have an intelligent conversation. You might almost think that moderation has any great bearing on the subjects that we discuss :)
In other words, this unmasks the myth that somehow exists that private innovators have no place in the big league of space. If billions of dollars and hundreds of scientists, plus the backing of a unified europe fails sometimes too, maybe there is hope for those who don't have as much resources but have the same if not greater desire.
http://cincyboys.blogspot.com/ Everything Cincinnati. Including the word 'Finnih'
Hmm, I guess it's how you judge the overlap. It's a good question, for one, whether we would have gone to the Moon when we did, or ever, without the race against the Soviets, a race with strong military overtones. Or to ask how much it would have cost to go to the Moon if ICBM and the Cold War had never happened. Either way, it is undeniable the U.S. was terrified of the Soviet Union, particularly its (largely imagined) nuclear missile capability. Kennedy ran in 1960 partly on a fabricated "missile gap" platform.
:); we subsidized it with many billions for grim military reasons, some altogether necessary. The secondary point, before anyone could say the cold war didn't waste trillions, was that military objectives are an inefficient way to pursue civilian space exploration. Programs like Ariane went straight to the target (I'm hoping here that Ariane never had military purposes?).
Small nukes? I don't think they got really small until the 60's, when we became interested in MIRV's. The ICBM business took its own path when it switched to the far more manageable and reliable solid fuel rockets, the Minuteman series. (I remember a Titan exploding when I was a kid because a wrench was dropped down the silo. It took them a while to figure out where the warhead has gone.) Obviously the Saturn V was designed with a special civilian purpose, but its roots were predictably military.
It was also not clear for a while whether we might have a manned military presence in orbit. Happily we went the stabilizing route of the ABM treaty instead. Oh yeah, the former ABM treaty -- but that's a whole 'nuther topic!
My point anyway was to humbly acknowledge that the American dominance of space flight wasn't just due to our brilliance and hard work and love of discovery
Gee, NASM even has a page on the military origins of the space race. I'm finding these things through Google, things I fuzzily recall reading elsewhere over the years. Anyway, what I'm seeing at the moment is a pervasive military motivation, even if the ways the monery was spent didn't always make sense. I would bet Americans somehow felt more secure that it was Americans landing on the Moon rather than Soviets. I remember the vague worries about being incinerated in the 70's quite clearly.
I don't believe that the civilian space program has ever fully disengaged from the military. The Space Shuttle itself was designed with significiant military purposes in mind. IIRC most of the military business went elsewhere after Challenger, and our satellite launching rockets may still be behind because of exaggerated hopes and hypes that the Shuttle could do it all. As the subsidies have been reduced the space program has suffered, to the point that I believe the military is very concerned with maintaining our current launch capabilities. I assume that the market for military satellites is still strong, and that the U.S. won't be launching these on foreign rockets anytime soon.
ARIANE 5 Failure - Full Report
s ter/about_cluster/cluster1/ariane5rep.html
"The reason why the active SRI 2 did not send correct attitude data
was that the unit had declared a failure due to a software
exception."
"The OBC could not switch to the back-up SRI 1 because that unit had
already ceased to function during the previous data cycle (72
milliseconds period) for the same reason as SRI 2."
"The internal SRI software exception was caused during execution of
a data conversion from 64-bit floating point to 16-bit signed
integer value. The floating point number which was converted had a
value greater than what could be represented by a 16-bit signed
integer. This resulted in an Operand Error. The data conversion
instructions (in Ada code) were not protected from causing an
Operand Error, although other conversions of comparable variables in
the same place in the code were protected."
"The error occurred in a part of the software that only performs
alignment of the strap-down inertial platform. This software module
computes meaningful results only before lift-off. As soon as the
launcher lifts off, this function serves no purpose."
"It has been stated to the Board that not all the conversions were
protected because a maximum workload target of 80% had been set for
the SRI computer. To determine the vulnerability of unprotected
code, an analysis was performed on every operation which could give
rise to an exception, including an Operand Error. In particular, the
conversion of floating point values to integers was analysed and
operations involving seven variables were at risk of leading to an
Operand Error. This led to protection being added to four of the
variables, evidence of which appears in the Ada code. However, three
of the variables were left unprotected. No reference to
justification of this decision was found directly in the source
code. Given the large amount of documentation associated with any
industrial application, the assumption, although agreed, was
essentially obscured, though not deliberately, from any external
review."
http://www.mssl.ucl.ac.uk/www_plasma/missions/clu
Well, the total number of launches seems incredible, but the reliability figure sounds about right over the long term.
I did a quick survey a few years ago of the reliability of heavy lift boosters, looking at the Atlas, Titan, Delta, and Ariane families. Of 1347 launches, the probability of success was 86%, but that included the rocky days of the early space program. When looking only at the last few years (1990-98), the reliability rose to 94%. Oddest of all was the Atlas E. Started in 1960 with 16 failures in 51 launches (69% rel.), then dusted off the remaining ones in 1980 and shot another 23 with only 2 failures (91%). Odd. I wonder what they did to them when readying them for launch that made them perform so much better.
Yup, that's roughly it, data overflowed.
The reason the code was still running after launch at all was that it was related to rocket gyroscope calibration and took a long time to set up. By setting it to carry on after launch as opposed to shutting down bang on takeoff was that, if there was a late abort, there could also be a really quick restart because they didn't have to recalibrate. This was sensible and was used at least once.
What wasn't sensible was:
* Carrying over code from Ariane 4 to 5 without checking the spec for differences, as it overflowed unprotected due to a ground speed reading Ariane 4 couldn't have achieved
* Having a redundant backup that was identical on the assumption that they'd only need one for random hardware failure. With this as a software failure, the two went almost simultaneously.
Greg
(Inside a nuclear plant)
Aaaarrrggh! Run! The canary has mutated!