Goodbye, Cassini

In about twenty hours, the spacecraft Cassini will plunge into the atmosphere of Saturn and destroy itself, to protect any potential life on Saturn’s moons. Can’t have Earth-life-tainted space junk floating around out there.

Cassini’s mission has been an astonishing success — with an emphasis on astonishing. It found things that turned some of our notions on their heads, and revealed a small moon with a liquid water geyser(!). It’s going to take a while to figure that one out.

I’ll not go into all the details; there’s actually a pretty nice write-up at fivethirtyeight, and you can get real-time updates straight from NASA.

The scientific instrument I most appreciate is the plain ol’ camera – Cassini sent home some beautiful images. Here’s a low-res markup of one of my favorites: A shot of Earth taken through the rings of Saturn.

The universe is still filled with mystery; we’re barely out of our own back yard and everywhere we turn we find things that astonish us. As we struggle with the trials of having a lot of sentient creatures packed onto the rocky parts of the surface of one small planet, we would do well to take a breath and look up, and be awestricken by what we see.


Seriously, NASA?

You may have heard about the impending arrival of our latest robotic explorer on Mars. The goal of this mission is to finally find those elusive six-armed ten-foot-tall green men and the super-hot (though delicate) princesses that current theory says have to be up there somewhere.

First, Curiosity has to land safely on the red planet. I have to confess that I’m a wee bit skeptical about this plan. I’ve linked to a video below, but before you go there, allow me to enumerate the stages of the landing.

  1. The mother ship releases the landing system. This is pretty routine at this point, and assuming no miles/kilometers snafus, should be all right.
  2. The craft hides behind its heat shield as it streaks through the atmosphere – this also fairly routine, except this time the payload can shift around behind the shield to get a little bit of steering. But it can’t see anything because it’s behind a heat sheild.
  3. Mars’ atmosphere is not thick enough to provide all that much braking, so now it’s time to deploy a parachute! I imagine the (estimated) shock of opening the chute has been tested many times, but needless to say, not in an atmosphere as thin as Mars’. So it’s all been simulations on the individual parts.
  4. As soon as the ‘chute is open, the heat shield has to go, so the lander can see the ground with its radar. This is the kind of thing that seems simple but so often turns out to be the killer. One explosive bolt doesn’t fire, and all is lost.
  5. But hold on, there, sparky! The parachute is still dropping too fast, and there’s not enough control over the landing spot. Now it’s time for… rockets! Controlled by computers! 500,000 lines of code! Holy crap. Several things have to happen at almost the same instant: all four rockets fire and the parachute is released.
  6. First maneuver: dodge the parachute. The lander will have to juke to the side. Remember, this machine has not been tested in conditions anything like Mars.
  7. Safe and stable, the lander will pick a sweet spot to set down the rover. It will not have help from humans.
  8. Oh, if only it were that simple. There’s a problem with dust, you see, if the rocket-powered hoverboard gets too close to the surface. (How close is too close? Well, now, how fine is the dust right there? How windy is it? Guess we’ll find out.) Rather than land on rocket power, our little miracle will hover and lower the rover on ropes. (How windy is it again? Are there any conditions the software wasn’t tested for?)
  9. After that, all that can go wrong is that the ropes fail to disconnect or the hover-thingie explodes and crashes onto the rover.

Right here I was going to say, “What? no ______s?” but I couldn’t come up with anything to put in the blank. (I’m sure lasers, ultrasonic beams, and explosives are all used in there somewhere.)

Here’s the promised link: Curiosity Before Mars: Seven Minutes of Terror

The entire sequence lasts seven minutes and we’re fourteen light-minutes away from Mars. We won’t hear anything back until the rover is either free and ready to roam or a twisted pile of junk. NASA is calling the seven minutes of descent “Seven minutes of terror.”

Now, there are a lot of smart people at NASA, and I’m sure I’m not going to come up with an alternative they haven’t considered. But really, I have to wonder if this is the result of solving a bunch of little problems instead of stepping back and reassessing the fundamental goal. Soft landing in a chosen spot without messing everything up with dust. Seriously, there has to be an easier way. It might involve a big-ass zip-lock bag.

Still, all this crazy complexity and systems that could not be tested in the actual environment has a pretty good chance of success. We’re actually getting pretty good at virtual testing, and engineering to amazing tolerances. I’ll be checking in on Sunday to see how the whole things plays out, and hopefully we can finally find that valley with the jewel-encrusted cliffs of solid gold.

Nice View They’ve Got

Astronomy Picture of the Day is one of my favorite sites, but yesterday’s edition was even better than most. I’ve always wanted to see the aurora borealis, and I will, dammit, but now I also want to see the northern lights from space.

Can someone hook me up?

Acerbia in Space

I woke up through a dream this morning, which gave me a chuckle that lasted all day. I think I called him Cassius in a previous episode, but that doesn’t matter; those who know this character get an extra bonus chuckle. The dream unfolded like this:

A buddy and I were visiting Cassius, who was looking after an orbital space habitat while the owners were away. It turns out there’s not much to do when you’re just revolving around the Earth like that, but we were hanging out, having a beer or two, and generally enjoying ourselves. We were playing some game that involved throwing things when the garbage lady showed up.

The garbage lady was a hillbilly-looking girl in stained overalls, her blonde hair was long and unwashed. A grubby baseball cap was pulled down over her eyes. She didn’t say much, just went about performing a perfunctory garbage-collection job. I felt a cold draft. I looked, and sure enough she hadn’t closed the hatch all the way, and our air was escaping out into space.

“Um… hello?” Cassius said to the garbage lady, “Yeah, I’m going to be here for another eight months, and that oxygen is going to come in real handy. Thanks.”