Even as Curiosity continues its trek towards Mount Sharp, NASA is already laying out the groundwork for its next Mars rover. The space agency aims to launch Curiosity's successor in 2020, a mission it's describing as the climax in a series of initiatives centered around the red planet over the coming decade. Today, the Mars 2020 Science Definition Team — a group NASA assembled in January — delivered a 156-page report that offers proposals touching on what will be necessary in a technological sense from the next high-profile rover.

"For many folks last summer, it was an incredible ride through the martian atmosphere," said John Grunsfeld, NASA's associate administrator for science. He was of course referring to the "seven minutes of terror," or the moments immediately preceding Curiosity's touchdown on the Mars surface. He also proudly boasted about Curiosity's discovery that Mars could have at one point supported life. "We still don't have the context of when that was in Mars' history," Grunsfield cautioned, saying that NASA hopes to learn more as Curiosity's voyage continues. But what's next?

"The SDT-preferred mission concept employs new in situ scientific instrumentation in order to seek signs of past life (had it been there), select and store a compelling suite of samples in a returnable cache, and demonstrate technology for future robotic and human exploration of Mars," the report outlines. Some fundamentals remain the same; as detailed in the report, the Mars 2020 rover would land in the same way as Curiosity and largely resemble its predecessor in overall size. But when it comes to instrumentation, the Science Definition Team is calling for finer tools that would allow the rover to take a closer, microscopic look at samples on the planet. "If life ever existed on Mars, we expect it to have been microbial microorganisms," said SDT member Abigail Allwood. That means the Mars 2020 rover will need to be capable of examining fine-scale layering in rocks and other samples — something Curiosity simply isn't capable of.

The goal is to bring pieces of Mars back to Earth, but how?

The Science Definition Team also wants to come up with a way of getting Mars science samples back home to laboratories on Earth. Their best idea involves a cache capable of storing up to 31 "diverse" samples in a protective container for later retrieval. As for how that pickup would work, the team admits plenty of "forward work" remains before a sensible plan can be finalized. One possibility, of course, is that astronauts could one day retrieve the samples when humans finally reach the red planet. And if all of this sounds a bit early and uncertain in nature, that's because it is; the SDT's exhaustive report merely proposes ideas that NASA can choose to embrace, improve upon, or ignore in the many years to come before the Mars 2020 rover is ready to depart. But the excitement is already there. Speaking of his colleagues on the Science Definition Team, chair Jack Mustard said he's "never seen so many emails exchanged" in the five and a half months the SDT has been assembling its report.