The Union Recorder

August 14, 2012

Curiosity’s Curious Landing

Beate Czogalla
The Union-Recorder

MILLEDGEVILLE — It’s been an exciting week for space exploration fans: the Mars Science Laboratory rover Curiosity made a text book case landing in Gale Crater on Mars in the wee hours of Monday morning, August 6. The media has been abuzz with news and you’d have to be literally living under a rock not to have heard about it. Science is way cool right now, geeks rule and everybody wants a piece of Mars.

The landing – horribly complicated as it was – went so smoothly, it felt about as routine as, say, putting gas into the car. The space capsule entered the atmosphere at a slight angle, caused by carefully placed tungsten ballasts. Those ballasts, or “slugs”, were ejected prior to the parachute opening, so the capsule would hang nice and straight on the chute once it opened. Eagle-eyed folks working with the Mars Reconnaissance Orbiter (MRO) have already spotted the six new craters on Mars that those ballasts made.

The parachute is a bit of a miracle in itself – at the insane speeds Curiosity was going in the thin Martian atmosphere it had to be a very large supersonic parachute. You can’t get those at the local Chutes’R’Us!

The heat shield was jettisoned right on schedule – and this is where something totally new for a Mars landing happened: cameras mounted on the rover that face straight down kicked in and filmed how the heat shield fell away, and then we can see in stunning detail how the Martian ground comes rushing up towards us.

Then the parachute was jettisoned and the amazing Sky Crane fired up its rocket thrusters, stopping the descent of the whole package in mid-air. It gently lowered the rover to the ground on some ropes, then cut the ropes and flew off a polite distance to promptly crash-land itself, since its job was quite done.

Seconds later, we had an image of a rover wheel on the Martian Surface.

The first images from Mars seemed grainy and blurry, but that’s just because the camera lenses still had their protective clear lens covers on. Once those popped off – after a safe time during which the dust settled – we got the clearest images of Mars yet. All of the lower rover cameras, those that are close to the ground, had those dust covers, since unlike all previous rovers, Curiosity was actually “outside” during the landing.

Past rovers all had issues with dust accumulation on their camera lenses and solar panels, Curiosity won’t have those problems as much – the high quality camera lenses on the upright mast all have baffles – kind of like a visor on a baseball cap – and when not in use the cameras will be pointed downwards, Curiosity will essentially be hanging her head, so that far less dust will get stuck on the lenses.

Last Wednesday I was in a teleconference with Aaron Sengstacken, who is the camera systems engineer for Curiosity, and of course he knows everything about those cameras and can literally talk about them for days. As a systems engineer it’s his job to make sure that the cameras (which were built by outside contractors) work with all the rover software and perform as designed, so there’s a lot of software development and coding needed. He mentioned that one of the reasons that they don’t install wipers or blowers is because the more mechanics you add to a rover, the more things can go wrong. And wouldn’t you hate having a grain of sand getting stuck in your wiper blade during the first week and either scratch the lens or worse yet – keep the blade stuck in front of the lens permanently? You can’t send a repair technician up there, after all.

All the people working on the MSL mission operate on Mars time. A Martian day is 24 hours and 40 minutes long. This means that slowly but surely your day will go out of synch with Earth time and you will at some point completely reverse your circadian rhythm. Because of this shift a day on Mars is also not called a “day” but rather a “sol”. The ease with which Mr. Sengstacken talked about “yestersol” was quite amusing to witness.

Curiosity is also not dependent on solar panels, as it carries its own RTG (radioisotope thermoelectric generators) which produce electricity for the rover’s operations. But that’s also not a limitless supply. The RTGs produce about 105 watts of electricity, 5 more than expected because it’s actually a little bit warmer on Mars than the forecasts predicted. The rover needs at least 130 watts when “awake” and more for additional science operations. So it charges its own batteries overnight and at the crack of dawn it’s ready to go again, using the remaining excess heat from the fuel pellets to keep warm during the dark hours.

Sengstacken expects the first movement of the rover around sol 9 or 10, and since we have those downward-pointing cameras he was excited about filming what he called a “sidewalk video” of the ground as the rover is moving.

By now all the cameras on the rover have been fired up and tested, the high-gain antenna has been calibrated and knows where to find Earth in the sky, and all comm systems are working perfectly. It’s easier and far more efficient for Curiosity to relay her data to an orbiting spacecraft which will then beam it to Earth, but in case none of those are available it can make direct contact via the dinner-plate sized antenna.

During the dark hours of every sol engineers and scientists work frantically to line up the rover’s activities, and just as sol-light breaks, they relay that information to the rover.

And another work-sol on Mars begins.

For up-to-date information on Curiosity visit the web pages at http://marsprogram.jpl.nasa.gov/msl/

Beate Czogalla is the Professor of Theater Design in the Department of Theatre and Dance at Georgia College & State University. She has had a lifelong interest in space exploration and has been a Solar System Ambassador for the Jet Propulsion Laboratory/ NASA for many years. She can be reached at   our_space2@yahoo.com