The European Space Agency spacecraft Venus Express, for which University of Colorado professor Larry Esposito is a mission scientist, concluded routine science operations this week after eight years in
orbit, and is now primed for its final assignment: an unprecedented plunge into the atmosphere of Venus.
"What we've been doing," said Esposito, who works out of CU's Laboratory for Atmospheric and Space Physics, "is using the fuel on the spacecraft to counteract gravitational effects, but we're running out of fuel. We can't avoid the ultimate problem."
After starting with roughly 570 kilograms of fuel, the Express is down to its last one or two. The tank will likely be completely empty sometime in 2014, though experts can't predict the precise date.
When it does run out of fuel, Esposito explained, it'll be less of a tragedy than an inevitability, and one that brings with it a rare opportunity.
"Now that it's at the end of its life," he said, "there's an opportunity to practice these sorts of operations that are a little bit risky."
The primary testing function the Express will assume involves a technique called aerobraking, in which the spacecraft relies on the friction of the atmosphere to change its own orbit.
Aerobraking, the European Space Agency says, is useful for getting spacecrafts into orbit around planets while conserving fuel.
Testing out aerobraking "will be precious for the preparation of future planetary missions that may require it operationally," said Paolo Ferri, head of mission operations, in a press release.
Once the Express runs out of fuel and plunges into the atmosphere, it'll be greeted by incredibly harsh conditions: wind quadruple that of Boulder's all-time record, and heat triple that of a pizza oven, to name a couple.
Aerobraking campaigns have been performed before, but they've never brought any spacecraft as close to Venus as the Express is slated to go. With a target distance of about 81 miles from the planet, this mission aims to go about 20 miles closer than ever before.
Regardless of how the next several months turn out, Esposito's already labelled the project a "great success."
He considers the crowning achievement to be measuring the composition of Venus' surface, and providing evidence that volcanic activity has taken place there.
Plus, considering the fact that many missions to Venus — including the most recent one, in 2012 by the Japanese — never even achieve orbit, even getting there is a success. The eight years of research, Esposito said, were far from guaranteed.
""It spacecraft engineering," he added, "it's hard just to go to Venus and have your mission work at all."