Just 10 days after NASA's Curiosity rover sent back its first colour photos of the Martian landscape, the US space agency says it wants to take a better look beneath the Red Planet's surface.
PHOTOS: Curiosity reveals more from Mars
"Does Mars have fault lines like the Earth does? How extensive are those? What kinds of 'marsquakes' are there?"
These, NASA official Lindley Johnson told reporters on a conference call on Monday, are some of the important questions the project hopes to answer.
The InSight mission, which aims to launch in March 2016, will send a device to Earth's next-door neighbour to measure seismic activity and a subsurface probe to measure the flow of heat from the interior.
"Seismology is the standard method by which we've learned to understand the interior of the Earth," explained John Grunsfeld, associate administrator for the Science Mission Directorate at NASA Headquarters.
"And we have no such knowledge for Mars."
InSight was selected from a pool of three finalists to be sponsored by the low-budget Discovery series.
The other two - one to explore a comet and another to take a closer look at Saturn moon Titan - were equally compelling, Grunsfeld said.
"All of these missions had top science," he said, adding that the proposals also all seemed equally realistic in terms of their ability to actually get answers.
But InSight won out because it seemed the most likely to come in on schedule and on budget, under the $US425 million ($A409 million) cap set for the projects. That cap does not include the cost of the launch vehicle.
Insight saved money by adopting a seismic monitor developed by the French space agency and a heat-flow probe developed by the German aerospace centre.
The project also incorporated into its design "proven systems" from NASA's highly successful Phoenix lander mission, which helped convince the selection committee it was a low-risk endeavour.
James Green, director of NASA's Planetary Science Division, says they anticipate it will take six months for InSight to reach Mars, and then a full Martian year - about 680 Earth days - to gather the data it is looking for.