The Mars solar conjunction places the sun directly between Earth and Mars about every 26 months. This puts communications between the planets at risk, prompting NASA officials to place a moratorium on commands sent to the rovers on the Red Planet.

While this is the first conjunction for the car-sized Curiosity rover, it's nothing new for NASA and the teams exploring Mars. On the opposite side of the planet, golf-cart-sized Opportunity enters its 3269th Martian day and fifth conjunction.

While some signals can make it to and from Mars, the normal daily routine of reviewing results from the previous Sol (Martian day, about 40 minutes longer than an Earth day) and sending up new mobility and instrument commands will be put on hold to ensure safety of the rovers. Corrupted images could always be resent but garbled commands sent to any spacecraft could be harmful.

NASA's Jet Propulsion Laboratory will continue to keep tabs on the Mars rovers and orbiters. Each rover will transmit a daily heartbeat directly via its X-band antenna as it rotates into view of Earth. The Odyssey and Mars Reconnaissance Orbiters will also assist in relaying information from the rovers via UHF band back home as well as store more complex images data gathered until the sun is out of the way.

During this time, members of the mission team will take this rare opportunity for some downtime. Some will take some well-earned vacations.

Rover drivers are cross training. Those who focus on getting the robot from point A to point B will learn more about operating the robotic arm and vice versa. Unlike previous rovers, Curiosity's arm is so complex that a team of rover planers (official but less cool sounding title for rover drivers) was dedicated to operating it. Others are using the time to focus on software updates that will be uploaded to the rover later this year.

The rovers will continue their science duties in place through the three-week period of the conjunction.

"For the entire conjunction period, we'll just be storing data on board," said Deputy Mission Manager Reid Thomas of JPL. About 12 gigabits of data from Curiosity is expected to start flowing once Earth is back safely in view around May 1.