Posted on 11/11/2014 10:03:25 PM PST by BenLurkin
We are now in the final hours before Rosetta’s Philae lander is released to attempt a first-ever landing on a comet. At 9:03 GMT (1:03 AM PST) on Wednesday, November 12, 2014, Philae will be released and directed towards the surface of comet 67P/Churyumov–Gerasimenko....
Rosetta’s and Philae’s software and hardware must work near flawlessly to give Philae the best chance possible of landing safely. And even with flawless execution, it all depends on Philae’s intercepting a good landing spot on the surface. Philae’s trajectory is ballistic on this one way trip to a comet’s surface. It’s like a 1 mile per hour bullet. Once fired, it’s on its own, and for Philae, its trajectory could lead to a pristine flat step or it could be crevasse, ledge, or sharp rock.
...
The gravity field of the comet is so weak, it is primarily the initial velocity from Rosetta that delivers Philae to the surface. But the gravity is there and because of the chaotic shape and unknown (as yet) mass distribution inside, the gravity will make Philae move like a major league knuckleball wobbling to the plate and a batter. Furthermore, the comet during the seven hour trip will make half a rotation. The landing site will not be in site when Philae is released.
And as Philae is on final approach, it will use a small rocket not to slow down but rather thrust it at the comet, landing harpoons will be fired, foot screws will try to burrow into the comet, and everyone on Earth will wait several minutes for a message to be relayed from Philae to Rosetta to the Deep Space Network (DSN) antennas on Earth. Philae will be on its own as soon as it leaves Rosetta and its fate is a few hours away
(Excerpt) Read more at universetoday.com ...
“The landing site will not be in site “
Face palm .......
You can’t really leap without gravity I think.
The problem is that this is neither a spelling nor a grammar error, just wrong word usage which automatic checkers aren’t smart enough to spot.
Lady just got done reminding people they are live on-the-air. Now a host and program is starting, it’s about 2 hours to release.
Writer Reyes loses sight when siting.
Life is just a leap of faith.
Spread your arms and hold your breath and Always trust your cape.
My favorite song by Guy Clark
http://www.youtube.com/watch?v=T6bZ37nexSY
I’ll be asleep by then, hopefully it is a success
Yep. Another homonymophobe...
That’s just the lander separation, seven hours after that the lander will reach the comet and make the landing.
We’ve got separation.
Been holding my breath the past half hour waiting to see if Philae successfully disengaged. And it did! WOOHOO!
I’ve been keeping an eye on this mission for a while, anticipating this day. Now to hope Philae can land successfully. I’ll be checking up on it first thing when I wake up later and I’ll be sleeping with all appendages crossed.
Landing in 6.5 to 7 hours from now. Lander’s on its own. Tune in around 6AM PST if you don’t want to miss it.
Oops, meant 7AM. Getting late. Can’t add.
Uh-oh... Thruster problem.
It’s operating from 28 light minutes away, that’s some major lag. It’s amazing that the lander can do this on it’s own considering too that it’s using 10 year old technology.
If I understand the reports correctly the lander’s engines are inoperative. They couldn’t be primed and will not fire to push it into onto the surface. It will have to rely on the “harpoons” to penetrate the surface then it will be “winched” down.
That does NOT sound like a plan with a high chance of success.
It may very well bounce off.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.