Kepler Makes First Exoplanet Discovery After Mission Reboot 28
astroengine writes NASA's Kepler space telescope has detected its first new extrasolar planet after mission engineers were able to save the mission from a premature death after two of the exoplanet hunter's four stabilizing reaction wheels failed last year. Called "K2," the extended mission arose from an "innovative idea" that appears to have given the prolific telescope a new lease on life. "Last summer, the possibility of a scientifically productive mission for Kepler after its reaction wheel failure in its extended mission was not part of the conversation," said Paul Hertz, NASA's astrophysics division director at the agency's headquarters in Washington D.C. "Today, thanks to an innovative idea and lots of hard work by the NASA and Ball Aerospace team, Kepler may well deliver the first candidates for follow-up study by the James Webb Space Telescope to characterize the atmospheres of distant worlds and search for signatures of life."
Why do these reaction wheels keep failing? (Score:3)
Isn't there any technology to keep reaction wheel discs floating in a vacuum chamber instead of using mechanical bearings?
How about magnetic suspension and frictionless motor drives? This has to be possible with today's technology.
Christian
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It wasn't 4 years, it is closer to 6. Launched in March '09. Secondly, there was a 3.5 year mission life, which Kepler satisfied. Now, even after sustaining some part failures, it continues to do valuable science. So, in fact, it looks like we've got a system that met all objectives and is working far past its design life - if that is pathetic, what would qualify as a success in your eyes?
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A bajillion dollars wont work.
You need rubber.
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Magnetic suspension? That sounds quite costly on a power budget, and a lot of these probes have really tight power budgets. Plus, you'd have to build in the ability for it to not get ripped apart during launch, which means overengineering the magnetic suspension just to get it off the ground even though that excess capability will never be used in space. I'd think mechanical reaction wheels would be a cinch to lock in comparison.
I'm probably wrong, but that was my initial gut thoughts on the subject.
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Well you could secure the wheel using some rectractable bolts during launch. Only when in orbit you retract these bolts and then you turn on your electromagnets.
I found quite a lot of research papers on magnetic suspension of reaction wheels. I really wonder why this isn't mainstream technology yet.
Christian
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Here's the thing. Imagine that you are a mechanical engineer, told to build a reaction wheel system that will have something like a 99% chance of lasting 3.5 years, and do it as cheaply, quickly, and lightly as possible. Are you going to pick an unproven, brand new bearing design that introduces lots of extra complexity, would probably involve a lot of new ($$$) and custom design work, and which require all the testing and validation that is involved to qualify a new technology for spaceflight? For starters
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There is such technology. On Earth. In space there are limitations of weight and energy consumption to contend with.
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Kepler was designed with a 3.5 yr mission life. It is now going on its 6th year in space. So it met what it needed to do and is STILL producing science. If they had blown time/money/mass on a fancier reaction wheel system, they might've had to sacrifice science payload, or power margin, or had the project go over schedule and over budget and get cancelled altogether. Not to mention that some other, more critical part could've failed because they would have had to sacrifice margin elsewhere.
Perfect is the en
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Of course, but you can't design for infinite lifespan. You design for the mission, add margin as required, and if it lasts longer, great. Almost always, it does, but this is a probability thing - there's every chance that you could get a 1 in a million, mission ending event on day one - there's no such thing as zero chance of failure. If you design for longer than required, you are spending more money/mass/time than you have to.
The real question is up to the principal investigator and his/her science team i
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We suck as a people (Score:3)
Seriously, we do.
The fact that we're finding other PLANETS is now so humdrum that this gets 7 comments, this smells very much like the latter Apollo missions "Oh, we've got guys on the moon again? Zzzz."
If I simply posted something controversial*, like an entire article about how "global warming is bullshit", that would get 300 comments, easily.
*of course, I can't use /. as my personal blog. I'm not Bennett Haselton.
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Seriously, we do.
The fact that we're finding other PLANETS is now so humdrum that this gets 7 comments, this smells very much like the latter Apollo missions "Oh, we've got guys on the moon again? Zzzz."
If I simply posted something controversial*, like an entire article about how "global warming is bullshit", that would get 300 comments, easily.
*of course, I can't use /. as my personal blog. I'm not Bennett Haselton.
More than 1800 exoplanets have been discovered. At some point, finding one more ceases to be big news.
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I was more interested in how they were able to run with only two wheels, that is more interesting at this point.
It turns out (pun intended) that they use the solar radiation pressure as the third wheel.
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If I simply posted something controversial*, like an entire article about how "global warming is bullshit", that would get 300 comments, easily.
That's practically a tautology. Of course you'll get comments if you post something controversial, since those tend to be matters of opinion and everyone's got a different one.
If you post about something that's a plain, simple fact (such as this discovery of yet another exoplanet) there really isn't a lot of room for discussion. 300 "Yes, this is a thing that happened" comments don't contain a lot of information.
The fact that discovering exoplanets has become routine is, in and of itself, awesome, but that
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And the innovative idea is... (Score:2)
Nice bit of click-baiting, failing to mention what the innovative idea actually was:
To maintain stability during its new campaign, mission engineers turned to the sun for help, using the continuous pressure of photons from sunlight to act as a counterbalance.