Japanese hack gets space probe back on track It took five years of painstaking work but the Japanese space agency has got its Akatsuki probe back on track. The Japan Aerospace Exploration Agency (JAXA) has confirmed that a careful combination of telematics, testing, and tentative orbital corrections have put the atmospheric probe into orbit around Venus, albeit half-a- …
Whether you call it a fix or a workaround, the ability of some people to figure out what they can do with what they are given is amazing.
How many projects are prematurely and unnecessarily declared failures because the manual, the specs, the documentation, declares that they have failed?
Because some weasels declare victory where there's none should neither void nor detract from damned hard earned success. These people managed to take an Awww shit and turn in an Atta-boy. Been there, done that too many times, and no, I didn't even get a T-shirt.
To that team: Damn fine work! I'd buy but I remember how much Kirins, Sapporos, and Asahis cost. Still, enjoy.
"The oxidizer was now useless, so the JAXA team dumped it to lighten the spacecraft."
Very interesting this. Are space probes usually made with components that can be jettisoned, or was that the plan once the probe was orbiting Venus? Are they using explosive bolts?
"Are space probes usually made with components that can be jettisoned, or was that the plan once the probe was orbiting Venus? "
Akatsuki used hydrazine (fuel) and nitrogen tetroxide (NTO, the oxidizer) for its 500-Newton main engine, and just hydrazine for its twelve attitude thrusters. NTO has a liquid range of -11C to 22C at 1 bar pressure, and is always stored as a liquid in spacecraft. (Its storage liquid nature is one reason for its popularity, the other being that NTO is hypergolic with hydrazine. )
Therefore, venting NTO is a matter of opening a valve and allowing the tank pressure to squirt it into space.
In Akatsuki's case, it was not deliberately planned to dump the oxidizer. Rather, when the main engine broke, nothing else on the spacecraft required the NTO. The little RCS motors didn't need it, the power systems didn't need, it was just dead mass that the little RCS motors would have to push around. So, a valve was opened and the oxidizer spewed into space.
Isn't everything?
Hydrazine is used in a wide range of industrial chemistry and does horrible things to living tissues, but that's all in non-hypergolic reactions.
It's usually oxidizers, not fuels, that are broadly reactive. Liquid oxygen, hydrogen peroxide, and the ever-popular chlorine trifluoride react energetically with many substances.
Dear alien overlord (not mine, so I fear you not)
If you have successfully designed a spacecraft and got it to orbit around another planet, you can comment on the design. Except that you would probably not, because you know how hard it is, and how much luck is needed. For all you know, the component failed due to micro-meteorite impact.
And yes, I did notice the smiley, but I am afraid the joke fell a bit flat, but it is always difficult, attempting humor in an alien language ;-)
...that none of the lead Japanese admins and techs on this project didn't commit "seppuku" at the time of the initial failure...as they really would have been up a creek without a paddle.
Good for them that their perseverance paid off. Hope they can get some data from it - they've waited long enough !!
Really? A relative who has worked on manned spaceflight admitted to me a few years back that he had found his old MSc thesis, and wasn't able to understand it.
Rocket science has moved on a bit since Isaac Newton. A quick look just at the three body problem will show you some interesting integrals.
This may be a bit long, but I had a tiny part in it's subsequent success.
Nearly 20 years ago I worked for a company that was part of a consortium to produce the Artemis satellite. One of the innovations was an ion propulsion engine that used xenon to keep the orbiter at the correct inclination.
This engine was quite small, not much more than a meter in length and had a series of small diameter tubes around 12mm in diameter, made from small sections of stainless steel (SS) pipe welded together, in order to transport the xenon from the tank to the engine. These pipes were welded using an automated autogenous welding machine.
The manufacture of the satellite had suffered numerous set backs and it was touch and go as to whether it would be completed due to budget over-runs and delay. The propulsion lab encountered a number of problems associated with the welding quite far into the production of the unit and the materials lab (on site) were asked to investigate.
Subsequent analysis from supplied welded coupon samples showed that some of the pipes were made from the wrong SS alloy (not connected with the welding problems). In order for SS to be welded and remain corrosion resistant then you have to use an alloy that contains titanium (or niobium), which preferentially forms titanium carbide rather than chromium carbide when welded, because you want the chromium to remain in solution which is what provides the corrosion resistance. If chromium carbide precipitates then the percentage of chromium in solution drops thus reducing the corrosion resistance and potentially lead to cracking. This is known as "weld decay".
For some reason 316 stainless pipe had been supplied rather 316L (niobium or titanium stabilised). When the project manager for the ion propulsion engine came into the lab and was informed of the error, he went green and had to be sat down with a nice cup of tea! It looked like this screw up would put the kibosh on the whole project. Millions wasted.
We had to find out the extent of the problem, so a tiny scraping of each pipe section that had already been welded and manufactured was taken (dozens of them) and then examined in the scanning electron microscope (SEM) to identify if the section was 316 OR 316L. It took 2 weeks and the diagnosis was not good. There was a mix-match of the two alloys across every transport tube.
In the mean time we asked the propulsion lab to produce enough welded sections from the two alloys so we could perform a complete re-qualification process in order to provide all the data for the engineers to say whether the ion propulsion engine was fit to be stored and then fly. The previous qualification process had taken 6 months. We did the new one in 4 weeks!
Some of us were sleeping at work (I bagged the labs photographic dark room!) and we would order in a takeaway each night followed by "a full english" in the morning from the canteen! (all on expenses of course)
Subsequently the ion propulsion engine was qualified to fly.
When the satellite was launched a failure of the launcher meant that the satellite was put into the wrong orbit. The only way to finally get the thing into the right orbit was to use the ion propulsion engine. It worked! The engine was so good that it was operating greater than the designed efficiency so was able to not only 'boost' it to the correct orbit but also provide a good lifespan.
It was a simple mislabelling of the bar stock at one supplier that led to the whole fracas.
https://en.wikipedia.org/wiki/Artemis_%28satellite%29
http://www.aerospace-technology.com/projects/artemis/
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