
Wow!
Congratulations to all concerned.
The ESA has succeeded in humanity’s first ever attempt to land a man-made probe on a comet after Philae touched down on the surface of Comet 67P/Churyumov-Gerasimenko. “Yes, yes, YES!” said Andrea Accamazzo, Rosetta flight director. “We see the lander sitting on the ground!” After a tense build-up, the European Space Agency’s …
Um, no. The probe and the satellite that has carried it are from ESA, that is, the European Space Agency, and the UK pays something like £240m per year towards ESA.
The photo will likely be greyscale as it'll be generated from images taken in the non-visible spectrum.
The comet is about twice the distance from the Sun as Mars (so 'daylight' is quite dim,) and the surface has an albedo similar to coal. Such conditions don't really lend themselves to colour photography.
Oh, now you've got me wanting to finish the calculation .....
Right. Call Philae 1m by 1m., and call the comet 3 km. by 4 km. That gives Philae 12 000 000 times its own area to land in. If the ratio of areas is 12e6:1, then the ratio of diameters will be about 3400:1. So making the bullet 866 picometres across. About a single atom, then.
Or, at full scale: Landing a washing machine within the city boundary of Derby, from 3.5 times as far away as the Sun.
Philae landed, yes, but the harpons weren't deployed. It's just sitting on the surface of the comet; it isn't anchored there. They might be able to try to deploy the harpons again, but the position is a bit precarious at the moment.
Still, well done for landing the thing in the first place. Whatever happens, it is a first in history. It is a proud moment for Europe.
To even imagine you could really make this happen 20 odd years ago was sheer audacity in itself; to make it work is simply astonishing. Heartfelt congratulations to all the visionaries who made it actually happen - you won't top this one in a hurry.
Here's hoping the results live up to it.
Another power source IS available - Philae has solar panels. However, they're not 100% sure that conditions on the surface will allow them to work sufficiently well to keep the bot going for any length of time*. Therefore they're assuming the worst - that the 64hr charge held by the battery is all they have - and are trying to fit all the high-priority tasks into that time; that way, any extra time provided by the solar cells is a bonus.
*Remember, this is someone we've never been before - at design time they had literally no idea, for example, how much dust would have been thrown up by the landing, and what it's characteristics would be - will it stick to and coat the panels, reducing their efficiency? Also at design time they had no idea how strong the sunlight would be at the landing site, how many of the cells would end up in permenant shadow from surrounding geography, etc. They'll now be finding out some of the answers to this - and this information itself is part of the data scientists will spend the next few years wringing as much knowledge from as possible. It's all exciting stuff!
Don't want to say "told you so", and I apologise for labouring the issue. The only people who must be happy about this are Greenpeace (no nukes in space). A power source that isn't dependent on environmental variables (such as not being stuck in shadow) must surely have merit.