Lots has happened on Mars since an unmanned rover named Curiosity landed Aug. 6 to explore the red planet. Last week the remote-controlled explorer passed its first test drive, traveling nearly 23 feet and taking snapshots along the way. NASA controllers in Southern California confirmed it can turn and back up. After other check-out tests, the rover will be steered about one-quarter mile to an intriguing area where three geological features meet.

During the two-year mission's opening weeks, Curiosity has taken measurements, sent back data and captured stunning high-definition photos of the Martian surface and shots of distant Earth -- as small as a star from the Martian perspective 35 million miles away. Closeups of Martian terrain show desert-like views of rocks and sand. In the months ahead, the tracked vehicle will study climate and geology, and collect data for a possible visit by astronauts some day. Curiosity can scoop samples and deliver them to its internal chemistry labs for on-board analysis.

Though any expensive manned mission is far off, NASA last week announced plans for a 2016 launch that will put instruments and cameras on Mars to determine its rotation axis precisely and measure the seismic waves and heat coursing through the interior. Space geologists don't yet know whether the core is solid or liquid. NASA also hopes to figure out why it doesn't seem to have drifting tectonic plates, like the ones here that cause earthquakes.

Project manager says: "We built a rover, and unless the rover roves, we really haven't accomplished anything." -- Peter Theisinger at Jet Propulsion Laboratory in Pasadena, Calif.

NASA head says: "The recent successful landing of the Curiosity rover has galvanised public interest in space exploration and today's announcement makes clear there are more exciting Mars missions to come." -- Charles Bolden, agency administrator, Aug. 20

Professor says: “This is sort of a step along the way toward manned missions to Mars in the distance future.“They're going to better understand the surface conditions of Mars regarding the soil, regarding the weather and regarding the radiation environment." -- Greg Clements, astronomer and physicist at Claremont University in Fremont, Neb.