Tuesday, November 11, 2014

The coolest thing ever, again

I thought this photo of Saturn from above was the coolest thing ever until I saw this:

That is a picture of a comet.  Not in the background, mind you, the foreground.  It was taken by the Rosetta spacecraft, which is currently in orbit around said comet (which is burdened by the unwieldy name of 67P/ Churyumov-Gerasimenko).  The scale is just under a meter per pixel.  If there was a human walking around down there, you could see her (just barely).  The photo is about 800 meters (half a mile) from side to side.

In the next few days, a lander will detach from the spacecraft and, if all goes well, will actually land on the surface of the comet.  This will be only the fifth place in the universe from which we will have photos from the surface, the other four being the moon, Mars, Venus, Titan (one photo), and of course, Earth.

My nominee for second-coolest-thing-ever is this awe-inspiring backlit shot of Saturn:

You can find more of these at the Cassini images hall of fame.

It is truly an amazing universe we live in.  (Too bad we're blithely destroying the best part of it.)


Tony said...

To nitpick: If there was a human on that comet and in that image, I believe you'd see a very bright pixel, as I believe the material there is very very dark.

Other than that: Isn't this fucking amazing!?!?! A freaking comet!!!!

On a related note... I don't care what the detractors says, I don't care what a mind-boggling expensive pork-barrel SLS/Orion is, I don't care that the science return might not be too big: I think that the ARM would be the best thing in human space flight that NASA did since Apollo 11 (BTW with Skylab in a distant third place). Can we please retrieve an Asteroid? And land humans on it? Please?

Tony said...

Did I write "… since Apollo 11 …"? I did (of course) mean since Apollo 17.

But other than that, why the heck don't they properly promote the ARM? It starts we the name. Why not call it the "Great Asteroid Grab of 2022"? And then we need to communicate the mission: "We are going to grab an Asteroid and we are going to fly it to an orbit near the Moon. And then we are going to land humans on it and bring back pieces of it. Because we are awesome. And nobody else can do it. And science!" But nobody is promoting it! Only people from JPL seems to actually be enthusiastic about it. NASA seems to hate it. It appears to me that NASA wants to drown the ARM mission by being disinterested.

ARM might not bring us to Mars, but it might bring us closer – the same way that Gemini did bring us closer to the Moon.

Ron said...

> If there was a human on that comet and in that image, I believe you'd see a very bright pixel

That's right. That's what I meant by "just barely". :-)

> Can we please retrieve an Asteroid?

Alas, almost certainly not. Bringing an asteroid to earth is really hard, but that part is a cake walk compared to *stopping* the asteroid once it gets here. The only way to do that is with aerobraking. To do that you have to thread the trajectory needle incredibly close. And if you miss you will essentially be detonating several hundred nuclear bombs at some random point on the earth's surface. It would be bad.

If you're looking for inspiration, I suggest the inverse mission: trying to *prevent* an asteroid from hitting the earth. That's actually doable, almost as cool as bringing an asteroid back, and ultimately could *literally* save civilization. See http://sentinelmission.org.

Tony said...

I have the feeling we are talking past each other: I was talking about the Asteroid Redirect Mission (ARM), what may (or may not, depending on politics) be the very next step of NASA's human space flight program.

And no, I don't want to bring the entire asteroid back to Earth, maybe I choose the wrong words (yeah, Redirect, not Retrieval) – bringing it to a distant retrograde orbit around the Moon will do just fine for me. The people at JPL say it can be done, and I trust them to do it without endangering Earth – no aerobraking necessary. And yes, I know that it is the same technology used to deflect dangerous asteroids – one more reason why I like it.

Moving an asteroid, ion engines, possibly a gravity tractor, or possibly capturing and despinning an rubble pile (IN SPACE!), human operations in deep space, retrieving samples and a technological step towards Mars – what's there not to love?

The hard thing is not bringing a NEA with up to 1000 metric tons mass to a lunar orbit (again, says JPL), the hard thing is finding such a NEA. Supposedly, there are lots of NEA in this weight class, however the smaller they are, the dimmer they are… So there is currently a NASA program to find as many of these "small" NEAs, an additional bonus resulting from ARM.

Ron said...

Ah. Well, you did say, "Can we please retrieve an Asteroid?" so I assumed that when you wrote ARM you meant Asteroid Retrieval Mission.

But it turns out even that is more feasible than I thought: