SAN FRANCISCO — Three missions selected as finalists in NASA’s competition to launch a robotic planetary expedition in 2016 offer startlingly different proposals. One would land in the sea of Saturn’s moon Titan. Another would tunnel into Mars. And a third would place the world’s first probe on a comet.
All three proposals have one thing in common, however: each team includes Denver-based.
“We are delighted to play a role on each of these three outstanding missions, but at this early stage of the competition, we need to deter specific details to each principal investigator,” said Lockheed Martin spokesman Gary Napier.
On May 5, NASA announced the three finalists in the space agency’s Discovery program, which supports robotic missions with a maximum cost of $425 million, not including the cost of a launch vehicle. Paul Hertz, chief scientist in NASA’s Science Mission Directorate, said he is enthusiastic about each of the projects selected. “These are cool missions: looking inside Mars, touching a comet, landing in Titan’s sea,” Hertz said. “I’m only sorry we’re not going to do all three.”
Instead, the space agency is providing each finalist with $3 million to conduct a nine-month concept study and prepare a report on plans for mission development, operations and science. Once those studies have been completed, an independent review board will evaluate the projects, paying careful attention to whether they can be carried out while adhering to the costs and schedules proposed, Hertz said.
NASA plans to announce the winning project in 2012, Hertz said. That deadline is unlikely to slip because as soon as a project is selected team members will have a lot of work to perform to prepare the mission to launch in 2016, he added.
Each of the three missions would investigate scientific phenomenon that have been largely unexplored. The Geophysical Monitoring Station (GEMS), for example, would use a thermal probe, a seismometer and a radio tracking system to study the interior structure and composition of Mars. Insights gained from the mission would provide information on the formation and evolution of Mars as well as other rocky planets, said Bruce Banerdt, GEMS principal investigator and a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“Mars is in the sweet spot to tell us about the first few 100 million years on Earth” because the same types of physical processes are likely to have occurred on both planets, Banerdt said. For Earth, that history has been lost during billions of years of tectonic activity. On Mars, the information remains accessible because the red planet appears to have experienced a relatively low level of geological activity for billions of years. “This is a mission to the early formation of planets,” Banerdt said.
The GEMS mission, managed by the Jet Propulsion Laboratory, would conduct its project with a copy of NASA’s Phoenix lander, which touched down on Mars in 2008. The lander would be equipped with a seismometer built by France’s Geophysics Institute in Paris with funding from the French space agency, CNES and a heat probe supplied by the German space agency, DLR, Banerdt said.
Another Discovery finalist, Titan Mare Explorer (TiME), proposes to land in, float on and study the methane-ethane sea of Saturn’s moon Titan. “This would be the first exploration of a liquid body beyond Earth,” said Ellen Stofan, TiME principal investigator and vice president of Proxemy Research in Gaithersburg, Md.
Ralph Lorenz, TiME project scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., added, “There are a whole slew of scientific discoveries that could be made and questions that could be answered. How are heat and moisture exchanged between the surface of the ocean and the atmosphere? How are waves formed? What is the chemical composition of the seas?”
The TiME capsule would be built by Lockheed Martin Space Systems and equipped with cameras built by Malin Space Science Systems of San Diego, a mass spectrometer built by engineers at NASA’s Goddard Space Flight Center in Greenbelt, Md., and a suite of meteorological instrument supplied by the Applied Physics Lab, which also would manage the project.
The third Discovery finalist, known as Comet Hopper, would send a probe to land multiple times on a single comet to study its evolution and interaction with the sun.
“We’ve had some amazing comet flybys but they have given us only snapshots of what a comet is like,” Jessica Sunshine, Comet Hopper principal investigator and a senior research scientist at the University of Maryland in College Park, said in a statement released May 11. “Comets are exciting because they are dynamic, changing throughout their orbits. With this new mission, we will start out with a comet that is in the cold, outer reaches of its orbit and watch its activity come alive as it moves closer and closer to the sun.”
The Comet Hopper mission would be managed by NASA Goddard. Other partners include Germany’s University of Bern, the Jet Propulsion Laboratory and New York-based Discovery Communications. The proposed Comet Hopper mission would study a small, short-period comet known as 46P/Wirtanen with cameras, an infrared spectrometer, a mass spectrometer and a thermal probe.
In the coming year, the Comet Hopper team will focus on the details of the mission, including prototyping, testing and simulation, Sunshine said in an email.
Two of the proposed Discovery missions, Titan Mare Explorer and Comet Hopper, would use the Advanced Stirling Radioisotope Generator, developed jointly by NASA and the U.S. Department of Energy to provide a long-lasting power source for space exploration. The generator was offered to all Discovery candidates at no cost.