Proposed AVIATR Project Captures the Scientific Imagination
The project has everything you could ask for to stir the imagination: an extraterrestrial world that is strange, yet similar enough to our own Earth to hold the ingredients for life, bizarre sounding physical processes to investigate, and an exciting new approach to the idea of an unmanned planetary probe. The project is AVIATR, or Aerial Vehicle for In-situ and Airborne Titan Reconnaissance, and its plan would be to send a nuclear-powered airplane to cruise the skies of one of Saturn's moons for up to a year or more. It's inherent appeal made it the subject of a flurry of recent coverage in popular science sources like discovermagazine.com and newscientist.com, and its lead scientist is Jason Barnes, Assistant Professor of Physics at UI.
While Barnes plays the role of lead scientist, there is a team of some 30 other scientists from 20 institutions in four countries that take part. If funded and realized, AVIATR would utilize the favorable physics on the moon Titan to keep the plane airborne for a long time. The atmospheric density on Titan is four times that on Earth, but gravity is only one-seventh of Earth's. That combination means that a plane could keep aloft with much less energy than is required here. "Flight is easier there than anywhere else in the solar system," says Barnes. The favorable physics allows for a significant payload of scientific equipment. Still, space and weight are always limited, and careful planning went into what should be included on the vehicle. "There are a lot of different kinds of science that a Titan airplane could do, and through a lot of thinking and some hard choices, we arrived at the payload of cameras and atmospheric sensors that we did."
Titan is one of the most Earth-like of all bodies in the solar system, and there are interesting aspects of its make-up that AVIATR could investigate. For instance, according to Barnes, the atmosphere on Titan is mostly nitrogen, like Earth's. However, unlike Earth, the remainder of Titan's atmosphere is mostly methane, and the effect of radiation breaks the methane into radicals, which recombine into complex organic molecules which then rain down on Titan's surface. "The entire system resembles the famous Miller-Urey experiment from the 1960's where they were able to produce amino acids inorganically from electrical discharges in a methane-ammonia atmosphere," Barnes explains. "The result is that with air to shield it from radiation, ubiquitous organics, and surface ice, Titan has all of the ingredients that we think are necessary for life -- except for a high enough temperature to melt the water. Therefore if water were to melt periodically, say from volcanism or a comet impact, then Titan would at least temporarily have what we would consider a habitable environment."
It's clear why the AVIATR has generated so much interest. One can hardly look at the artist's renderings of the AVIATR craft in action (see the accompanying image by Michael J. Malaska) without feeling the power of space exploration to captivate the imagination. If enthusiasm for the AVIATR project continues and events go favorably in the next funding cycle (still several years away), we may see a realization of all that excitement in the skies over Titan.
The original paper of Barnes et al is available here: http://www.springerlink.com/content/76117941970t5291/