The terrain where Curiosity rests looks remarkably like the Mojave Desert, a fact mission chief scientist John Grotzinger attributes to its probable formation from material brought down from the northern rim of the crater, much as running water paved the surface of the California desert.

“With Curiosity, we landed in something that actually looks very Mars-like, but also it looks Earth-like, with those mountains in the background,” Grotzinger says. “It's really cool, so it kind of makes you feel at home. I think the great experience there is, we're looking at a place that feels very comfortable, and what's going to be interesting is going to be to find out all the ways that it is different.”

Scientists already are studying a pair of half-meter-deep pits in the loose Martian soil north of the rover that apparently were dug by the plumes of the MSL descent-stage rockets. At the bottom of one of the holes is what appears to be bedrock, giving the science team an early baseline for soil depth as they explore across the alluvial fan.

With its fiscal 2013 budget request, NASA dropped its plans to work with the European Space Agency's (ESA) ExoMars program on a mutual campaign to return samples from Mars, starting with selection and caching of samples for future return to Earth. John Grunsfeld, NASA associate administrator for science, said here the night Curiosity landed that sample return continues to be the U.S.' next step on Mars, although hopefully at lower cost than the $2.5 billion MSL-class missions envisioned earlier.

Manning, who likes to point out that he was the chief engineer on both the cheapest and the costliest Mars-landing missions to date, says it should be possible to realize some cost-savings by reusing the MSL sky-crane technology to put payloads on Mars. One more sky crane can be built from engineering spares, and some of the development work would not need to be repeated for possible landing missions after that. But the MSL sky crane was custom-made for the current mission, a decision made to save money that may turn out to be more expensive in the long run. And, regardless of the specific robotic-mission options, the payloads still will need to be developed.

There will be more robotic missions to scout locations for human missions. “This isn't 'Star Trek;' we won't boldly go where no man has been before,” says NASA planetary-science chief Jim Green. While those future robotic missions probably will fit into the one-metric-ton landing capability demonstrated by the MSL sky crane, human missions will be much heavier—20-80 metric tons.

The technologies that will be needed to land those payloads safely—possibilities include hypersonic aerodynamic decelerators, supersonic inflatable decelerators and supersonic retropropulsion—are still being developed. But Manning and other engineers here believe there is wide appreciation that future exploration options must include the kind of expertise that allowed Curiosity to land.

“I do think people understand and would expect extensive simulation, characterization and verification,” says Matt Wallace, the MSL flight system manager, who has been working with NASA's Mars Program Planning Group.

Opportunities to launch missions to Mars come up every 26 months. Planetary scientists and the engineers who support them consider the 2018 opportunity as particularly favorable for transporting a sizeable payload to Mars. But Orlando Figueroa, NASA's “Mars czar” brought back from retirement to head the Mars planning group, has said the $700-800 million that will be available for Mars exploration in 2018 probably will not be enough to mount a landing mission (AW&ST May 14, p. 27).