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Discussion in 'The Watering Hole' started by cvanc, Nov 12, 2014.
Fantastic job. 10 years in the making followed by 10 years in transit. It's even more incredible when you realize they did it with '90s technology.
Looking forward to watching the documentary on the science channel tonight.
Just saw this on the news. This is awesome!! First the flipping sweet mars landing and now this! Science is awesome.
There's a problem that's getting zero play. The anchoring harpoons didn't fire upon landing. Elsewhere I read that upon separation from Rosetta, the thruster mounted on top of the lander which is meant to fire the instant the harpoons fire to prevent the recoil of the lander off of the surface indicated that it had issues. It could easily be that the harpoon anchors didn't fire because the lander control software would not fire them if the thruster was inop. Strange that that is not mentioned in this post from the lander's twitter account:
"I’m on the surface but my harpoons did not fire. My team is hard at work now trying to determine why."
If the harpoon anchors aren't eventually fired, comet outgassing could at some point blow the lander away from the surface.
I am guessing that not having the anchors in place might also make it hard to use some of the scientific tools if they exert pressure or torque. I don't think you would want to use the drill if you weren't anchored in place. Hopefully they can get it fixed.
Winston, I noticed earlier on the ESA Rosette website about the harpoon anchors, but later it was taken down. I just assumed the problem was fixed, but maybe I was wrong.
It sank 4cm into the surface. In that low gravity, that's gotta mean the surface is really soft. Wonder if harpoons will do any good?
The Rosetta team's web page here:
references that lander twitter account I linked to and that anchor problem post was the last thing posted there. Also, this tweet from an ESA twitter account:
RT @esa: "Maybe today we didn't just land once...we even landed twice!"
It apparently bounced on landing. I don't know if that was due to the anchors firing and successfully anchoring the lander, but there was recoil due to the top thruster not firing or what. Someone else said on that page two hours ago:
I really don't like the sound of that. Sounds like something went very wrong. Why such enthusiasm?
I'll be watching the lander's twitter page. Very strange.
Where'd you find that kind of detail? I'd love to read anything else they have there.
Finally getting some mainstream media attention. This was posted two hours ago:
We landed twice: Philae comet probe may have bounced after harpoon failure
Comet 67P has a very weak gravity, so anchoring harpoons were designed to shoot into the comet to fix the spacecraft to the surface. They failed to fire and Philae is not firmly secure, ESA says.
Philae lander manager Stephan Ulamec said the probe may have lifted off again and turned.
"So maybe we didn't land once -- we landed twice," he told a news conference. "Did we land in a soft sand box or is there something else happening? We don't fully understand what happened," he said.
Philae also carries a drill that can drive 20 centimeters (8 inches) into the comet and deliver material to its on-board ovens for testing. He also said the probe could start drilling into the surface and analyzing the material as soon as Thursday.
Not if they can't get those anchors fired... and from what I've read elsewhere, I'm not even sure that they're sure that the lander is still correct side up.
I'm going to have to go with a comment found on the ESA twitter account, "Why such enthusiasm" considering the uncertainty at this point?
The lander has a descent imager, so hopefully that can tell them something, plus we'll get a very cool descent movie once they've stitched all of the images together:
Tweet from @Philae_ROMAP
"magnetic field analysis revealed 3 landings at 15:33, 17:26 and 17:33 UTC"
The first bounce lasted for almost 2 hours. The gyros shut down after the first contact. The lander could be in any orientation. Need more data - fingers crossed.
From what I was reading earlier, it sounded like the onboard batteries won't last all that long, so they don't have tons of time to 'debug' and "fix" stuff.
It's amazing. Even if everything isn't perfect, we sent a pretty small piece of machinery out into space and managed, after ten years of travel, to have it intercept a comet all while traveling tremendous speeds and covering huge distances... Needle in a haystack is nothing compared to that!!!
What's the best website to look at to keep up to date with the investigation about Philae's mission and news updates on it?
So if the harpoons didn't fire and the gyros are shut down then it never really landed. It's just slowly bouncing in the extremely low gravity of the comet. The comet's gravitational acceleration at the surface is about 1/10000th that of Earth's. The lander has a mass of 100 Kg, so it weighs 220 pounds on earth. On the comet it would only weigh 0.4 ounces. It might eventually land on the comet after the bounces damp out, but it won't be able to exert much force against the surface without pushing itself away again.
Unfortunately, it seems to have bounced into a ravine and is in shadow too often as the comet rotates. It's absolutely amazing to me how hard it is to find hard tech info on this. Space.com doesn't even mention anything other than the lander bounced, not giving any kind of clue that it bounced 1km back into space on the first bounce!
After two bounces, the first one about 1km back out into space, the lander settled in the shadow of a cliff, 1km from its target site.
It may be problematic to get enough sunlight to charge its batteries.
"There is a limited amount of battery power there and the solar panels are not really illuminated, so we don't know precisely how long it's going to last," said Rosetta mission manager Dr Fred Jansen.
... early reports indicate that in its present position, the robot is receiving only one-and-a-half hours of sunlight during every 12-hour rotation of the comet.
This will not be enough to sustain operations.
As a consequence, controllers here are discussing using one of Philae's deployable instruments to try to launch the probe upwards and away to a better location. But this would be a last-resort option.
At least it's upright, but look at the shadows:
So it seems that it did land after the second bounce. Hopefully they can use one of the instruments or harpoons to push it back away from the surface so it has a chance to land in a better location. Otherwise they're not going to get much science information from it where it is currently located.
XKCD has been having fun with Philae:
I'm happy it happened.
I just wish it had this flag on it:
The latest and it sucks:
Rosetta: concerns for comet lander after uneven landing (with some nice photos)
Pictures taken by Philae of its surroundings show it pressed up against what appears to be a hard wall of some kind.
Telemetry indicates it is on a slope or perhaps even on its side.
Certainly, one of its three feet is not in contact with the surface.
The key issue vexing controllers right now is the lighting conditions.
Philae is receiving about 1.5 hours of illumination during every 12-hour rotation of the comet.
This will be insufficient to top up its battery system once the primary charge it had on leaving Rosetta runs out. That was some 60-plus hours.
It means Philae is unlikely to be operating in its present state beyond Saturday.
Not good. Hopefully it is still able to do much of the science it was meant to do. I wonder if they will be able to use the drill or get a sample to analyze.
They may not be able to do everything they had hoped for, but I am thinking they will still be able to do a lot.
It just illustrates how hard it is to conduct a perfect mission in deep space 10 years after the launch.....
"One of the steps to prepare for landing did not proceed as planned. A cold-gas jet -- a nitrogen thruster -- is supposed to fire upon landing in order to counteract any tendency for the lander to bounce off the surface. In order to prepare the thruster for use, a pin must puncture a wax seal over the gas reservoir. There were two redundant pins, and two efforts made to fire each of the two pins, but no pressure change happened after four attempts."
Such a very simple thing totally screwing up at the last minute such a phenominally complex mission after 10 years of traveling to the comet in a very complex path.
Philae is somewhere here:
Photo 131 ft from surface during (first) landing. Boulder is 15 ft in diameter:
Latest briefing starting at lander status:
This show was great! What an impressive probe and lander! Repeats probably going to be available for viewing:
SCIENCE CHANNEL LANDS #1 MOST WATCHED TELECAST OF THE YEAR WITH "LANDING ON A COMET: ROSETTA MISSION"
Special Grabs 763,000 Total Viewers
Following yesterday's unprecedented comet landing, viewers were glued to Science Channel on Wednesday, Nov. 12 to watch LANDING ON A COMET: ROSETTA MISSION which documented Rosetta Comet's behind-the-scenes rise to launch and explored the historic mission which landed the Philae probe on a comet 310M miles from Earth yesterday.
LANDING ON A COMET: ROSETTA MISSION, which aired at 9PM,delivered 763,000 Total ViewersP2+ and ranked as the NETWORK's MOST WATCHED TELECAST OF THE YEAR IN TOTAL VIEWERS breaking a four year streak against Punkin Chunkin 2010. The special also ranks as the SECOND MOST WATCHED TELECAST IN NETWORK HISTORY IN TOTAL VIEWERS (P2+) solidifying the undeniable fascination of yesterday's historic space mission. The special also earned a.6 in Men 25-54, beating cable news networks that included CNN, CNBC, and FOX News Channel, and other cable network that included A&E, History2, ESPN2, Comedy Central and MTV, among others.
Latest update is that battery power will probably not last through today. They are going to try to extend an arm in hopes that it might tilt Philae into the sun.
What a real shame! They hope that it might get enough solar power and wake up periodically once the comet gets closer to the sun.
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