Friday, May 04, 2007

Hey, I Was Right!!

It's not often that I feel the need to quote myself, but I predicted something scientific and space-related that might actually turn out to be true, and now I have to revel in my brief moment of rightness. Back in July of 2006, I read a report from NASA that the Cassini spacecraft had found evidence for lakes of liquid methane on Titan, one of Saturn's moons. I took a mental leap--not a huge one for the real sciency types, but a respectable leap for me:

Scientists will continue to observe the areas, looking for evidence like changes in size, or surface roughness stirred by winds, to indicate whether they've guessed correctly. If they're right, Titan is "the only body in the solar system besides Earth known to possess lakes." Not exactly the place you'd want to go for a summer vacation. One usually heads to a lake for fresh air and exercise, but Titan's not really a fresh air environment, is it? All that methane and ethane might make it a little hard to head out for a hike, or row a canoe, wouldn't you say? What a shame; it would be such an adventure to head to a lakeside cabin off-world. Oh well, there's got to be a bright side, right? Hmmm, liquid methane...liquid methane...sounds like a possible built-in fuel depot to me. That's it!! Titan can be the gas station on the way to some other cool vacation spot that we'll discover any day now. It's not quite as fun as finding Shangri-La on some other planet, but it will have to do.

My big prediction, somewhat flippantly expressed, was that someday Titan's lakes could fuel our journeys to other exciting destinations. Guess what? NASA thinks I'm right!! Well, okay, NASA doesn't know anything about me and my little bloggy predictions, but I can at least say that NASA agrees with me. NASA is testing a methane rocket engine, hoping to take advantage of the abundance of methane just waiting to be harvested from our neighboring planets. Patrick Barry, writing at NASA's Science website, says that methane engines "could eventually be key to deep space exploration."

Some of the advantages to the methane engine include the fact that liquid methane can be stored at a higher temperature than liquid hydrogen (the current fuel of choice for the soon-to-be-retired space shuttle.) This would mean less insulation, and thus less weight to haul off of planet Earth. Liquid methane, according to Barry, is also denser than liquid hydrogen, which would make the fuel tanks smaller, lighter and, ultimately, cheaper. Barry quotes project manager Terri Tramel of NASA's Marshall Space Flight Center as adding safety to the list of methane's perks:

Methane also gets high marks for human safety. While some rocket fuels are potentially toxic, "methane is what we call a green propellant," Tramel says. "You don't have to put on a HAZMAT suit to handle it like fuels used on many space vehicles."

Here's the gravy, though, as far as the NASA-proving-me-right part of this little self-congratulatory post goes. In our solar system, methane is basically ubiquitous, so rockets wouldn't have to carry fuel for the whole journey along with them. They could pick some up along the way:

But the key attraction for methane is that it exists or can be made on many worlds that NASA might want to visit someday, including Mars.

Although Mars is not rich in methane, methane can be manufactured there via the Sabatier process: Mix some carbon dioxide (CO2) with hydrogen (H), then heat the mixture to produce CH4 and H20--methane and water. The Martian atmosphere is an abundant source of carbon dioxide, and the relatively small amount of hydrogen required for the process may be brought along from Earth or gathered in situ from Martian ice.

Traveling further out in the solar system, methane becomes even easier to come by. On Saturn's moon Titan, it is literally raining liquid methane. Titan is dotted with lakes and rivers of methane and other hydrocarbons that could one day serve as fuel depots. Imagine, a methane-powered rocket could allow a robotic probe to land on the surface of Titan, gather geological samples, refill its tanks, and blast off to return those samples to Earth. Such a sample-return mission from the outer solar system has never been attempted.

The atmospheres of Jupiter, Saturn, Uranus and Neptune all contain methane, and Pluto has frozen methane ice on its surface. New kinds of missions to these worlds may become possible with methane rockets.

So, Titan may well turn out to be an interplanetary gas station, as well as a geological destination-of-interest in its own right. Speaking of destinations-of-interest, head over to the NASA article if you want to watch the video of the new rocket in action in the Mojave desert. It's way cool, and downright pretty, with this really impressive blue flame. They're still working on the project, with tweaks to be done before a methane-fueled rocket can blast off the launchpad, heading for fabulous holiday destinations like the Lakes of Titan, but the pretty blue test was a promising start.

The best part of all this scientific and spacey advancement, from my perspective? I got to be right! (Hey, cut me some slack. It doesn't happen that often.)