BOULDER, Colo. -- NASA has awarded $3.3 million to the University of Colorado at Boulder for a one-year concept study to land a spacecraft on Venus.

The university could land $650 million more to actually make the mission to Venus. CU-Boulder is one of three finalists for space exploration projects that would launch no later than 2018. The other finalists are the University of Arizona and Washington University in St. Louis.

The proposed mission at CU-Boulder would study Venus's surface, climate and atmosphere to try to determine what led to its harsh conditions and toxic atmosphere and to predict its ultimate fate in the solar system.

CU-Boulder Professor Larry Esposito, a science team leader on the Venus mission proposal, said the mission would allow scientists to better compare Venus with other planets, including Earth, Mars and Mercury, as well as planets recently discovered orbiting stars in other solar systems. Scientists also are interested in the "runaway global warming" on Venus, Esposito said.

While Venus and Earth were similar at birth, Venus has since turned into "Earth's evil twin" because of its extremely harsh and inhospitable conditions, said Esposito, of CU-Boulder's Laboratory for Atmospheric and Space Physics.

It has been 25 years since a spacecraft last landed on Venus.

"Our curiosity and scientific capabilities have increased dramatically," Esposito said. "This mission will be a big step forward in understanding planetary evolution both in our own solar system and in planetary systems around other stars."

As part of the university's proposed Surface and Atmospheric Geochemical Explorer, or SAGE mission, a lander would descend onto the flank of an active volcano on Venus, then instruments would dig down about 4 inches into the surface. The spacecraft would zap the soils with two lasers and a vacuum tube would shoot large pulses of neutrons, which would bounce data back to the lander on surface composition and texture.

The lander would be constructed to survive the harsh conditions on Venus for at least three hours, Esposito said.

"Venus has gone terribly bad since it first formed," he said. "The surface pressure is 100 times that of Earth and its temperature is similar to that of a self-cleaning oven."

Venus also has a toxic atmosphere filled with carbon dioxide gases and acid rain, he said.

"Understanding the physical and chemical reasons for this uncontrolled warming may help scientists better understand the eventual fate of Earth," Esposito said.

The proposed Venus mission will build on data collected by the European Space Agency’s Venus Express Mission, an orbiter launched in 2005 that is carrying a camera, two spectrometers, a radio science experiment and a space plasma and atom-detecting instrument. Esposito, who is a co-investigator of the European mission, said Venus Express has detected several volcanoes with possible recent lava flows, and data from the mission was used to select the proposed landing site for the CU-Boulder mission.

NASA will choose one of the three proposals for full development after reviewing each university's yearlong study.

The University of Arizona has proposed sending a spacecraft to orbit an asteroid and collect material from the surface. Washington University has proposed landing a craft in a basin near the moon's south pole to collect materials. The goals are to understand the formation of the solar system and relationship between the Earth and the moon.