WASHINGTON, May 6 (UPI) -- NASA said Friday it will choose its next mission from among studies of the inside of Mars, a sea on a moon of Saturn or a comet's nucleus.
Teams will get $3 million apiece to sketch out each mission, and one will be chosen for a 2016 launch, the space agency said.
The winning project is to cost no more than $425 million, not counting the cost of the launch vehicle.
One option, the Geophysical Monitoring Station, would study the structure and composition of the martian interior.
The Titan Mare Explorer would carry out the first direct exploration of an extraterrestrial ocean by landing in and floating on a methane-ethane sea on that moon of Saturn.
The Comet Hopper probe would study comet evolution by landing on a comet repeatedly and observing its changes during its course around the sun.
Meanwhile, the European Space Agency said Friday images from its Mars Express show a system of deep fractures in the crust around the Isidis impact basin. Some of the cracks are 1,600 feet deep.
It is believed the basin buckled under the weight of volcanic lava.