Kepler Telescope suffers critical failure

Cylinder

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Cylinder
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Apparently, another reaction wheel has failed on the Kepler space telescope that, if not corrected, would end the spacecraft's primary mission of detecting Earth-like exoplanets. These reaction wheels keep the telescope aligned while observing stars for transits. Last year, wheel 2 became unstable and was shut down. This weekend, wheel 4 indicated that it had failed and could not be turned.

At our semi-weekly contact on Tuesday, May 14, 2013, we found the Kepler spacecraft once again in safe mode. As was the case earlier this month, this was a Thruster-Controlled Safe Mode. The root cause is not yet known, however the proximate cause appears to be an attitude error. The spacecraft was oriented with the solar panels facing the sun, slowly spinning about the sun-line. The communication link comes and goes as the spacecraft spins.

We attempted to return to reaction wheel control as the spacecraft rotated into communication, and commanded a stop rotation. Initially, it appeared that all three wheels responded and that rotation had been successfully stopped, but reaction wheel 4 remained at full torque while the spin rate dropped to zero. This is a clear indication that there has been an internal failure within the reaction wheel, likely a structural failure of the wheel bearing. The spacecraft was then transitioned back to Thruster-Controlled Safe Mode.

An Anomaly Review Board concurred that the data appear to unambiguously indicate a wheel 4 failure, and that the team’s priority is to complete preparations to enter Point Rest State. Point Rest State is a loosely-pointed, thruster-controlled state that minimizes fuels usage while providing a continuous X-band communication downlink. The software to execute that state was loaded to the spacecraft last week, and last night the team completed the upload of the parameters the software will use.

The spacecraft is stable and safe, if still burning fuel. Our fuel budget is sufficient that we can take due caution while we finish our planning. In its current mode, our fuel will last for several months. Point Rest State would extend that period to years.

We have requested and received additional NASA Deep Space Network communication coverage, and this morning the Anomaly Review Board approved the transition to Point Rest State later today. Because this is a new operating mode of the spacecraft, the team will closely monitor the spacecraft, but no other immediate actions are planned. We will take the next several days and weeks to assess our options and develop new command products. These options are likely to include steps to attempt to recover wheel functionality and to investigate the utility of a hybrid mode, using both wheels and thrusters.

With the failure of a second reaction wheel, it's unlikely that the spacecraft will be able to return to the high pointing accuracy that enables its high-precision photometry. However, no decision has been made to end data collection.
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I hope they can fix it but even if they can't there's a huge volume of data generated still to be worked through.
 
Oh that's tragic. The methodology pretty much relies on some degree of longevity. The potential planet transits have to be observed more than once for confirmation, which means at least over one of each planet's year. If the mission is shortened, it will only be able to confirm planets with relatively short years.
 
They can work wonders with spacecraft pointing sometimes. SOHO should have been done ages ago except for some wonderful spacecraft pilotage.

However, if it goes now it does so with an embarrassment of riches. I don't think anybody had any idea just how many planets this would find, and we are likely to see new ones come out of this data as the processing methodologies improve.
 
JoeTheJuggler said:
Oh that's tragic....
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I know exactly how you feel.

But I don't agree that it's tragic. A tragedy is when somebody dies, even if it's in pursuit of the greatest goals -- in this case, a grand and splendid search for knowledge.

And that's why I'm so glad I've lived into the age of UNmanned space exploration.
 
Of course, since we no longer have human launch-to-orbit capacity, having fully and most likely permanently ceded military control of space to the USSR, China, and probably even the DPRK via anti-science budget cuts brought on by a bunch of YEC types who couldn't stand the evidence that was coming home, there's no way to fix this, and the USA will continue down its 2nd-world path of rot.
 
Really sad news. :(

NASA’s Kepler space telescope malfunction may end hunt for planets

The Kepler Space Telescope, the celebrated discoverer of worlds around distant stars, may have found its last planet. NASA announced Wednesday that the telescope, which to date has cost $600 million to build and operate, has lost the ability to point accurately.

It’s not dead, but by going wobbly it can’t do the precision observations necessary for spotting signs of “exoplanets.” Kepler is 40 million miles from Earth, too far away to be fixed even if NASA still had a space shuttle and could throw together a repair mission.

“Kepler’s not in a place where I can go up and rescue it, or any other astronaut,” said John Grunsfeld, the head of science at NASA who became famous as an astronaut for his missions to fix the Hubble Space Telescope.
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So there will be no mission like the one to fix the Hubble.
 
Rocketboy 1.0 and I got to see the Kepler telescope when it was in the cleanroom at Ball getting prepped for transport. While I'm sad that the mission is likely over, the mission was quite successful. Like all good science the Kepler project answered questions, and those answers will lead to more questions.
 
Silly Green Monkey said:
How is it too far away? We got it there, didn't we?
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Astronauts and repair-missions can only get into low Earth orbit. Unfortunately, a satellite in low Earth orbit will pass in and out of the Earth's shadow every 90 minutes, subjecting it to temperature swings that wreak havoc with calibrations and stability. Kepler's science mission is all about calibration ultra-stability; when a planet passes in front of a star, the star might dim by something like 0.001%. To detect this, your brightness measurements need to be rock-solid-stable.

Therefore, Kepler was loaded onto an extra booster rocket and launched on an orbit that's drifting farther and farther from the Earth. No day/night temperature swings, no glow from a planet below you, no 90-minute periodicity in cosmic ray exposure, etc.. We do not now and never have had a technology for sending astronauts that far.

JWST will do something similar for similar reasons.
 
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jj said:
Of course, since we no longer have human launch-to-orbit capacity, having fully and most likely permanently ceded military control of space to the USSR, China, and probably even the DPRK via anti-science budget cuts brought on by a bunch of YEC types who couldn't stand the evidence that was coming home, there's no way to fix this, and the USA will continue down its 2nd-world path of rot.
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As far as I can tell USA still has the best military launch and space capabilities. What you do not have anymore is overpriced shuttle techs which so far as I can tell were never a good military asset to begin with.
 
Silly Green Monkey said:
How is it too far away? We got it there, didn't we?
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It wasn't deployed by humans into LEO, it was launched on a rocket into orbit around the sun, in an orbit that is close to Earth but not bound by it. To get to the satellite and repair it would require a robotic mission, because it's ~160 times farther away from Earth than the Moon is. That would cost more than the entire budget of the Kepler program (~600M US) and likely have a high chance of failing.

It would be cheaper to just launch a second Kepler telescope than to try to fix the current one. Hopefully something of that nature occurs.
 
jj said:
Of course, since we no longer have human launch-to-orbit capacity, having fully and most likely permanently ceded military control of space to the USSR, China, and probably even the DPRK via anti-science budget cuts brought on by a bunch of YEC types who couldn't stand the evidence that was coming home, there's no way to fix this, and the USA will continue down its 2nd-world path of rot.
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Space-X has something to say about that.
 
jasonpatterson said:
It would be cheaper to just launch a second Kepler telescope than to try to fix the current one.
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Yup. Kepler was never designed for orbital servicing. They can send commands to try to trick the hardware into righting itself, but that's about it. From the suspected failure that the team describes, I'm guessing the hope is to revive wheel 2.
 
They could send up a small craft that has just a reaction wheel, receiver, and a large clamp to hold it to Kepler.
 
Pulvinar said:
They could send up a small craft that has just a reaction wheel, receiver, and a large clamp to hold it to Kepler.
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I think they should just send up a tripod, 'cause in my photography class they told me that a tripod was the most stable thing you could mount a camera on. That would totally fix it. I'm surprised those NASA idoits didn't think of that BEFORE they put it in outer space.

In all seriousness, the reaction wheel idea is very interesting. I don't know how they'd go about getting it to the telescope and attaching it, but that'd be a very cool fix. Placement would be so critical though.
 
Pulvinar said:
They could send up a small craft that has just a reaction wheel, receiver, and a large clamp to hold it to Kepler.
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That's a brilliant idea! It seems to me that firmly attaching the new reaction control would be the biggest mechanical problem.

Making it talk to the Kepler software, though... I have no idea how that would work.
 
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