Long-Lost Comet Lander Philae Found (seeker.com)

astroengine writes: With only a month before its mission ends, the European Space Agency's Rosetta mission swooped low over Comet 67P/Churyumov–Gerasimenko to see the stranded Philae lander jammed in a crack. After months of searching for the lander, which made its dramatic touchdown on Nov. 14, 2014, mission scientists had a good idea as to the region the robot was in, but this is the first photographic proof of the lander, on its side, stuck in the craggy location called Abydos. "This wonderful news means that we now have the missing 'ground-truth' information needed to put Philae's three days of science into proper context, now that we know where that ground actually is!" said Rosetta project scientist Matt Taylor in a statement.

Comments

Re:too bad

[drinkypoo]

Not being able to admit flaws and failures points to a very weak character.

Is that why you didn't log in?

Re:Too bad it didn't have a RTG

[Brett Buck]

And quadrupled the weight.

Overall a disappointing mission

[Ecuador]

I don't like to talk bad about the labors of perhaps good engineers, but it did seem there were some issues with the design of this mission. Granted, landing on a comet is a delicate process, however it lacks the extra difficulties that planetary landings have, especially when you have to speed through atmosphere and apart from having to break you have to make sure your instruments are protected from the ordeal. So the fact that (without having the craft go through such an ordeal as atmospheric breaking etc) both methods that Philae had available for a good landing, the gas thruster and the grappling hook, were DOA is pretty bad compared to the performance of other crafts. And forget about the grappling hooks which are unusual, how do you screw up a simple thruster, something that has been implemented in various forms thousands of times for various satellites.
Sure, there was some interesting science gained, but that was not thanks to the part of the team responsible for the landing...

Re:Overall a disappointing mission

[ColdWetDog]

Have you ever actually worked on a project like that? You don't get an unlimited engineering, time or weight budget. You sometimes have to make guesses and assumptions. Sometimes those don't entirely work out. You almost never get to make it as robust as you would like.

Not to mention that no one had ever done this before. You know, 'boldly go where no one has gone before' type thing.

Reality is a bitch at times.

Re:Overall a disappointing mission

[XXongo]

I don't like to talk bad about the labors of perhaps good engineers, but it did seem there were some issues with the design of this mission.

Landing on a comet had never been done before, and the engineers didn't even know what the surface looked like, much less that it had this amazing double shape and rugate surface.

There are two approaches to doing something that's never been done before: (1) Try something and see what the problems are, (2) Think out every possible trouble area that might manifest, and make sure that you can deal with that. Approach 2 sounds much better, but when you take that approach, the vast majority of problems you're designing to deal with are ones that don't actually occur, and as a result the engineering cost is much, much higher.

They designed a lander that would operate on batteries in the worst case, and would stick to the surface with their harpoon and operate on solar arrays in the best case. They got the worst case-- and, because they designed it to operate even in the worst case of landing in an adverse location at a bad orientation, they got data.

They did good. And they got good engineering information to use on later missions.

Re:Overall a disappointing mission

[Applehu Akbar]

The heart of the mission was being able to keep station with a comet as it approached perihelion and then moved outward again. This gave us our first close-up view of exactly what happens to a comet as it approaches the sun. The lander mission was gravy.

The one big disappointment of the mission was the attack at the first press conference by the most virulent alien lifeform in our solar system, social justice warriors. This is not how we do science, people.

Re:Overall a disappointing mission

[Ecuador]

I don't understand why I can't say that part of the project was botched. I have actually worked on projects that required the finished product to "work 100%" when put in production (not "in space" the closest I have reached is satellite communication software) and it was not a matter of "unlimited engineering, time or weight budget", it was mostly a matter of solid design and especially testing. In this particular case, it seems that they either did not fully vacuum-test their harpoon firing, or the test was not right and they actually found this would be a problem while the probe was in space, from other people tests if I understand correctly! http://archive.wired.com/wired... (see comments section). They thought they had found a solution, bit it either did not work, or there was an additional problem with the wiring.
Also a gas thruster is sort of a simple device, I think you just have to make sure it doesn't leak. But it failed as well. That's 2/2 control systems gone...

Re:Overall a disappointing mission

[Solandri]

I thought the mission performed poorly too, but your criticism is off-base. The surface gravity of the comet was several hundred thousand times less than Earth gravity. It wasn't like landing on Mars. It was like docking with the International Space Station, except without a docking adapter. Landing on a planet is relatively easy in contrast because you've got a huge margin of error by which you can over-thrust and still land successfully. e.g. On Earth, basically everything between 0 and 1g upward thrust will still slow you down, yet will not compromise your landing (cause you to lift back up) after you touch down.

When docking in zero-g or near-zero-g, you need to match velocities precisely - the margin of error is almost nil. That's why they went with the harpoon system - because docking is a damned difficult thing to do even when you have a docking adapter and a computer and human pilot right there giving real-time thrust correction inputs.

I expected more from the mission only because the Japanese pulled off an even tougher "landing" (the asteroid was about 1/300th the mass of the comet). That spacecraft however was designed as touch-and-go, rather than permanently landing ("attaching" is probably a better word at these low surface gravities).

Re:too bad

[hackertourist]

If there was a failure, it wasn't a failure of mission control. Nothing they could have done would have changed the outcome.

The landing had a combination of problems. Harpoons and thrusters not firing (design flaws), and the landing zone having different geology than had been assumed (nobody had landed on a comet before, so no definitive data to go by).

Despite the problems, the mission gathered most of the data they wanted. Not an overwhelming fail by any stretch of the imagination.

Re: too bad

[Anonymous Coward]

You can read the mission objectives they had written before the mission was actually launched and see that they achieved nearly all of them. Unless they have a time machine, there is no failure cover-up and your the one trying to spin things to suit your agenda.

Summary fail

[silentcoder]

It completely fails to mention the IMPORTANT thing: what shirt was he wearing at the announcement ?