SAN FRANCISCO – NASA's Curiosity rover is getting a younger brother. A new robotic probe made mostly out of Curiosity's spare parts and systems will be launched to Mars in 2020 and begin exploring the planet.

"The new science rover builds off the tremendous success from Curiosity and will have new instruments," said NASA associate administrator of science John Grunsfeld during a completely packed NASA Town Hall lecture here at the 2012 American Geophysical Union conference on Dec. 4. He added that the agency has budgeted $1.5 billion for the mission over the years leading up to launch, though the figure is pending congressional approval.

In the coming months, NASA will place a call for new instrument ideas from the scientific community. One possibility that Grunsfeld mentioned was to have the new rover collect and store samples that a later mission could retrieve and return to Earth for scientists to inspect here. Such a sample-return mission has long been a dream of the planetary science community since it would allow them to conduct experiments that would be impossible on Mars.

"We are ready to cache samples," said astronomer Steve Squyres of Cornell University, who leads the Spirit and Opportunity Mars rovers team and chaired the planetary science decadal, which outlined which missions scientists would like NASA to conduct over the next 10 years.

But there are already concerns within the planetary science community about the cost of such a mission and whether or not NASA could better spend its money elsewhere. Curiosity famously ran over budget and was delayed two years, eventually costing $2.5 billion. Furthermore, there are other planets in the solar system that could be explored. Scientists who study places like Saturn or the icy moons of Jupiter seemed particularly stunned by the news.

"NASA doesn't apparently value anything besides Mars. I just. I don't. I have nothing," tweeted planetary scientist Sarah Horst from the University of Colorado, who studies the atmosphere of Saturn's moon Titan.

Considering NASA's current budget woes, which have hit planetary science particularly hard, there are worries that any cost overruns on this new Mars mission might affect Discovery or New Horizons missions, which have often funded spacecraft to asteroids, moons, and other bodies in the solar system. At least at the AGU Town Hall meeting, NASA seemed particularly Mars focused, mentioning several Red Planet missions it would launch or participate in with international partners, such as the InSight drilling probe, but addressing no other new missions.

Image: NASA/JPL/Wired Science