NASA has narrowed down to three proposals for its next venture to another celestial body in the solar system. One of the proposed missions was submitted by the University of Colorado at Boulder (CU-B), which was awarded $3.3 million for a detailed, one-year concept study for a lander mission to Venus to study the history of its surface, climate, and atmosphere, as well as to predict its ultimate fate in the solar system.
According to Larry Esposito, a Professor at CU-B's Laboratory for Atmospheric and Space Physics and Science Team Leader on the Venus Mission Proposal, CU-B's proposal would allow scientists to better compare Venus with other terrestrial planets—including Earth, Mars, and Mercury—as well as planets recently discovered orbiting stars in other solar systems.
"It has been 25 years since a spacecraft last landed on Venus, and our curiosity and scientific capabilities have increased dramatically," said Esposito. "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 CU-B's proposed Surface and Atmosphere Geochemical Explorer (SAGE) mission, the lander would descend onto the flank of an active volcano on Venus known as Mielikki Mons, which is about 200 mi across and 4800 ft in altitude. Once the lander was in place, instruments on the spacecraft would dig down about 4 in into the surface and then "zap the soils with two lasers and a vacuum tube shooting large pulses of neutrons, which would bounce back data to the lander with information on the surface composition and texture," said Esposito.
The lander would be constructed to survive Venus conditions for three hours "or more." To put those conditions in a personalized context, Esposito describes Venus' surface temperature as being "similar to that of a self-cleaning oven," with a surface pressure 100 times that of Earth, the latter of which, fortunately, us earthlings have less context.
"Venus has gone terribly bad since it first formed," he 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. We are very interested in what sent Venus down this hellish path, including its runaway global warming."
Venus also has a toxic atmosphere filled with carbon dioxide gases and acid rain. "Understanding the physical and chemical reasons for this uncontrolled warming may help scientists better understand the eventual fate of Earth," he said.
According to the proposal, some of the instruments destined to fly (and, considering the conditions, eventually die) on SAGE include temperature, pressure, dynamics, and wind-speed hardware; a flyby camera; a tunable laser spectrometer to measure stable isotope ratios; and a neutral mass spectrometer to measure gases. The lander also would carry descent and panoramic cameras, a microscopic camera, a neutron-activated gamma ray spectrometer and a third spectrometer to measure surface and subsurface composition minerals and elements.
"The minerals that make up the Venus upper crust are still unknown," said Esposito. "The new information would allow our scientific team to better compare Venus to the other terrestrial planets in our solar system and beyond."
CU-B's 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-B mission.
SAGE partners will include the Jet Propulsion Laboratory, which would provide the SAGE project management; Lockheed Martin, which would build the carrier spacecraft; the Ames Research Center; the Goddard Spaceflight Center; and the Langley Research Center.
SAGE's robotic arm for digging into the surface of Venus would be contributed by the Canadian Space Agency, according to Esposito.
The two other proposals selected by NASA for further study include one led by the University of Arizona to rendezvous with and orbit a primitive asteroid and return a piece of a near-Earth asteroid for analysis and one led by Washington University in St. Louis to drop a robotic lander into a basin at the moon's south pole and return lunar rocks back to Earth for study.
The final selection will become the third mission in the program. New Horizons, NASA’s first New Frontiers mission, launched in 2006, will fly by the Pluto-Charon system in 2015 and then target another Kuiper Belt object for study. The second mission, called Juno, is being designed to orbit Jupiter from pole to pole for the first time, conducting an in-depth study of Jupiter's atmosphere and interior. It is slated for launch in August 2011.