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NASA's Kepler Enters Emergency Mode 75 Million Miles From Earth (theverge.com)
Loren Grush, writing for The Verge: NASA engineers have declared a mission emergency for the agency's planet-hunting spacecraft Kepler, which has somehow switched into emergency mode. Now that a mission emergency has been declared, the Kepler team has priority access to NASA's deep space telecommunications system in order to try to get the spacecraft back to normal operations. Emergency mode is the lowest operational mode the spacecraft has. It also requires a lot more fuel than usual, which is why the Kepler mission team is working hard to get the spacecraft back to normal. But communication with Kepler isn't easy. The spacecraft is estimated to be 75 million miles away from Earth right now, according to NASA, so any communications signal traveling at the speed of light will take up to 13 minutes to travel to and from the spacecraft. Kepler has detected nearly 5,000 exoplanets over the years -- of which 1,000 have been confirmed.
You know, if you say "is", you really don't have to say "currently" or "right now", much less both.
~7 minutes for a signal to get there, and another ~7 minutes for the reply to come back. Sounds like 13 minutes to me, given a bit of rounding.
To & from is 150 million miles, which works out to 13 minutes. How did they 'fail'?
Safe mode probably use thrusters instead of reaction wheel to control the attitude. Reaction wheel works with electricity (from solar array, so "unlimited"), thrusters use fuel.
Even if they don't get ti fixed, Kepler has had an absolutely amazing run. The initial planned mission lifetime was 3.5 years, and that was in 2009. So we've gotten almost twice as much out of it as it was planned.
One of my favorite computer games from the 1990s was Masters of Orion II, 4X space exploration/conquering game. One thing in that game and many similar games was the idea that you couldn't find out what planets were in a star system until you had actually sent a probe there. It is absolutely amazing that shortly after those games were made, we had the technology to detect planets in other star systems while remaining in comfort here.
Why the hell don't sigs show up on the mobile site?????
Because, sigs is short for signature, and signatures were originally on paper...aka STATIONARY. Therefore, they can't be mobile.
rewriting history since 2109
Have gnu, will travel.
From the SOHO spacecraft web page:
In other words, the spacecraft goes into a mode where the only thing it does it point at the Sun, to keep the power flowing, and it does so by using fuel, not the reaction control wheels. As fuel is a limited resource, that would be bad if it continued too long.
What's a reaction wheel then? Some kind of gyro system?
What kind of internet access do you have that lets you get to Slashdot, but not Wikipedia?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
A gyro to rotate you, not sense your rotation - here are the Kepler reaction wheels. (It has already had 2 reaction wheel failures.)
Note: Inertial sensing gyros are generally gimbaled, so they can stay rotating in the same direction. Reaction wheels are generally fix mounted, and are spun up and down as needed to get the desired attitude (or rate of rotation). If the spacecraft is being torqued by something (say, a small gas leak), the wheels will spin faster and faster to soak up the excess angular momentum until they reach their design limit, and have to be despun. This is called a momentum dump, and requires some other system (i.e., thrusters) to finally get rid of the excess angular momentum.
Basically, it's a wheel that you can speed up or down with a motor. The axis of the wheel is fixed to the spacecraft body. When you accelerate the wheel rotation, its angular momentum increase. But as the total angular momentum of the spacecraft does not change, the rest must rotate in the other direction, by reaction. Typically you include several of them in one spacecraft because each of them only control one axis.
Given that we know that Kepler has a bad batch of reaction wheels, that two of the four have already failed, and that this emergency mode happened while the spacecraft was being repointed to the Galactic Center for a microlensing campaign, which inevitably would mean a lot of reaction wheel use, I very much fear that this means that another reaction wheel has failed and the K2 mission is over.
Typically spacecraft software is computer verified for its correctness -- the main reason it is so expensive. So using Rust would not have helped.
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
if you want to call those that seek scientific information about the universe nutters go ahead; if you want to jerk off at the end of life of successful monumental project go ahead, you're just being a jerk-off troll.
kepler already did its job and from backlog of data which is still being processed we'll know percentages of what types of stars have what kinds of planets, distributions of rocky and gaseous planets, percent planets in habitable zone and also gas giants in habitable zone.
Correction: A "computer" can not "verify" *all* software for correctness.
It makes quite a big difference, there is an entire field devoted to Formal Verification.
Slashdot: where don knuth is an idiot because he cant grasp the awesome power of php
As of Sunday morning, the Emergency Mode was resolved; and the spacecraft was returned to normal mode. https://www.nasa.gov/feature/m...
Self-importance and self-indulgence is the root of ALL evil.