Comet Lander Falls Silent; Scientists Fear It Has Moved 36
vivaoporto writes: European scientists say the Philae comet lander fell silent on Monday, raising fears that it has moved again on its new home millions of miles from Earth. Over the last few weeks, Rosetta has been flying along the terminator plane of the comet in order to find the best location to communicate with Philae. However, over the weekend of 10-11 July, the star trackers struggled to lock on to stars at the closer distances. No contact has been made with Philae since 9 July. The data acquired at that time are being investigated by the lander team to try to better understand Philae's situation.
One possible explanation being discussed at DLR's Lander Control Center is that the position of Philae may have shifted slightly, perhaps by changing its orientation with respect to the surface in its current location. The lander is likely situated on uneven terrain, and even a slight change in its position – perhaps triggered by gas emission from the comet – could mean that its antenna position has also now changed with respect to its surroundings. This could have a knock-on effect as to the best position Rosetta needs to be in to establish a connection with the lander.
The current status of Philae remains uncertain and is a topic of on-going discussion and analysis. But in the meantime, further commands are being prepared and tested to allow Philae to re-commence operations. The lander team wants to try to activate a command block that is still stored in Philae's computer and which was already successfully performed after the lander's unplanned flight across to the surface to its final location. "Although the mission will now focus its scientific priority on the orbiter, Rosetta will continue attempting – up to and past perihelion – to obtain Philae science packets once a stable link has been acquired," adds Patrick Martin, Rosetta mission manager.
One possible explanation being discussed at DLR's Lander Control Center is that the position of Philae may have shifted slightly, perhaps by changing its orientation with respect to the surface in its current location. The lander is likely situated on uneven terrain, and even a slight change in its position – perhaps triggered by gas emission from the comet – could mean that its antenna position has also now changed with respect to its surroundings. This could have a knock-on effect as to the best position Rosetta needs to be in to establish a connection with the lander.
The current status of Philae remains uncertain and is a topic of on-going discussion and analysis. But in the meantime, further commands are being prepared and tested to allow Philae to re-commence operations. The lander team wants to try to activate a command block that is still stored in Philae's computer and which was already successfully performed after the lander's unplanned flight across to the surface to its final location. "Although the mission will now focus its scientific priority on the orbiter, Rosetta will continue attempting – up to and past perihelion – to obtain Philae science packets once a stable link has been acquired," adds Patrick Martin, Rosetta mission manager.
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Oh, My Foot!
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Re:Way to Go Metric System (Score:4, Informative)
At worst it was a fairly successful mission.
Rosetta, the orbiter, plays a very large role, and has been functioning properly.
Philae the lander was designed for two missions:
-Short term, upon landing do a battery of tests powered by primary (non-rechargable) battery. This was a success
-Long term, small battery of tests over a long period of time, powered by secondary (rechargable) battery and solar cells.
The choice of power systems was for the reason of the risk of what happened. It landed in shade but the primary batteries allowed the tests to complete. Because they aren't NASA, Nuclear based RTG power isn't viable.
Here's some interesting papers on the actual missions and design of the vehicles:
http://www.researchgate.net/pu... [researchgate.net]
http://www.kiss.caltech.edu/wo... [caltech.edu]
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If you shave with an Occam, that's actually the most likely explanation. Although Philae was equipped with ice-anchor feet, these did not take hold and the lander is just resting on the comet. Because its weight on that tiny body is the same as one sheet of paper, any outgassing as the comet approaches the sun will literally blow it away.
This could be a horror movie (Score:5, Funny)
We land a spacecraft on a comet for the first time. It loses power, but when it comes back online...it's different. It's moving. And we don't know what it's up to.
I'm not saying it was aliens..... (Score:2)
Maybe it needed some "me" time (Score:2)
Can't a lander get a day off 'round here??
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Yeah, don't be silly. They're military hardware, not eggs!
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Jack O'Neill: Carter... I can see my house!
Why directional? (Score:2)
I wonder why the lander's antenna is directional when it only communicates with the orbiter. That doesn't seem like enough distance to warrant directional.
Re: Why directional? (Score:1)
I'm no expert, but I would guess the decision to use a directional antenna is so it wouldn't need as much power.
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Many probes have both a unidirectional antenna for high throughput, and an omni-directional antenna for emergencies. The omni-directional one typically would send & receive a very slow and simple signal with basic tracking and status info.
Stupid European scientists (Score:2, Funny)
I don't know what they're going on about Philae going silent. All they have to do is check its twitter feed [twitter.com] and see that its still communicating.
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obvious solution (Score:2)
if it moved, just ask for it's forwarding address. :)