What's Ahead for the Mars Curiosity Rover?

PASADENA, Calif.—In a pre-landing press briefing Saturday morning at NASA's Jet Propulsion Lab (JPL), a panel of five scientists and engineers confirmed that everything is on track for the Mars Science Laboratory's landing on Mars Sunday night.

"The team is confident and thrilled to be finally arriving at Mars," said Arthur Amador, the MSL mission manager at JPL. "We are reminding ourselves to breathe every so often," he added.

Curiosity has been flying under autonomous control and is now less than 500,000 miles from the Red Planet. The team cancelled Friday night's opportunity to correct the rover's trajectory, a good sign that it is headed for its landing target in Gale Crater.

During entry, Curiosity will lose sight of Earth as it falls off Mars's horizon and the spacecraft will no longer be able to communicate directly. The team has tweaked the orbits of Odyssey, the robotic spacecraft orbiting Mars, and the Mars Reconnaissance Orbiter (MRO) to pass over Curiosity during parts of its entry, descent, and landing (EDL) stages and relay data back to Earth at different time scales.

Because the exact dynamics of EDL are uncertain, there is a chance communications may drop and NASA will not receive confirmations. After landing, though, there will be four vital opportunities to communicate with Curiosity and verify that systems are working correctly, explained Richard Cook, MSL deputy project manager at JPL.

The first chance will occur at 12:30 a.m. PDT, two hours after landing, when Odyssey passes over the rover, and again at 11:30 a.m. PDT. Shortly after, at 11:40 a.m. PDT, MRO will fly over and it may be possible to receive some black and white hazard camera pictures taken from the back of the vehicle, though they will be low-resolution 50-by-50 pixel images. During the mission, data will mainly be transmitted via the orbiters, rather than directly from Curiosity to Earth, since the orbiters have more power and larger antennas than the rover.

At 5:30 p.m. PDT the following day, the rover will communicate directly with Earth for the first time without orbiters through the Deep Space Network (DSN) using an ultra-high frequency signal. That communication won't transmit any data, but will simply consist of a line of code called an event record, similar to a short text message, that tells scientists how fast the rover was traveling when it touched down and where it has landed. At that point, if communications have not come through, it will be unlikely that the mission can be considered successful.

For more on how Curiosity will phone home, watch the video below.

Following that period, if all is going well, Curiosity will transition into normal surface operations. Early, planned surface activities include high gain antenna deployment on Aug. 6; mast deployment on Aug. 7, with the ability to take photos with the MastCam and navigation cameras previously inaccessible; testing of instrument functionality and capture of the first 360-degree panorama on Aug. 8; a quiet day for data return on Aug. 9; and the beginning of a prepared flight software transition that is already loaded but not yet running on Aug. 10.

Cook also presented a longer-term calendar of planned surface activities. Early August will be mainly be focused on transmitting the first images and engineering checkouts. In mid-August, the rover will begin payload and sample system checkouts. Early September will mark the first drive and in mid- to late September, Curiosity will take its first scoop sample. Further down the line, in October or November, the rover will take its first drill sample.

As always, the panel reserved the weather report for the end of the briefing. Ashwin Vasavada, the MSL deputy project scientist, said that the dust storm spotted two days earlier just south of Gale Crater no longer poses a threat because it has drifted in another direction. Weather maps show some water ice clouds over Mars, a good sign of a cold atmosphere that is relatively free of dust.

"Mars appears to be cooperating very nicely with us," Vasavada said.

Continue to check back for more updates as Curiosity prepares for landing, expected at 10:31 p.m. PDT and Sunday, Aug. 5. PCMag will be live-tweeting the momentous event from NASA's Jet Propulsion Laboratory in Pasadena, Calif. beginning at 9:30 p.m. PDT.

For more, check out , as well as the slideshow above, which includes PCMag's recent tour of JPL.