14 DAY TRIAL // Scientists in charge of operating Opportunity, one of the two components of the Mars Exploration Rovers (MER) mission, say that they will need to let the spacecraft conduct operations on its own for 16 days, due to planetary alignment issues that will cut off contact between Earth and the Red Planet.
This is not something that hasn't happened before. In fact, say mission controllers, this is the fourth time contact is lost with the rovers. This is caused by a planetary alignment setup in which Mars passes directly behind the Sun, as seen from our planet.
Such an event is called a solar conjunction, and it would appear that it will last for a bit more than two weeks in this instance. Even though it will not be able to receive commands from Earth, the rover will not waste time, as it will keep on conducting science.
The massive energy of the solar radiation prevents radio transmissions from getting through between Earth and Mars during conjunctions, so MER mission managers decided to upload a series of commands to Opportunity before the cosmic phenomenon begins.
As a general rule, NASA prefers not to send commands during such events, as interferences from the Sun can hamper with the code lines, causing damage in the target spacecraft. This is what happened to the Cassini spacecraft in orbit around Saturn just a couple of months ago.
The 2011 solar conjunction will begin on January 27 and will last until February 11, announce mission controllers at the NASA Jet Propulsion Laboratory (JPL), in Pasadena, California. The Lab is managed by the California Institute of Technology (Caltech).
The Mars Reconnaissance Orbiter (MRO) and Mars Odyssey spacecraft will also be affected by the cosmic event, and they too will receive no instructions over these 16 days. The two missions are managed by the JPL too.
“Downlinks from Mars spacecraft will continue during the conjunction period, though at a much reduced rate. Mars-to-Earth communication does not present risk to spacecraft safety, even if transmissions are corrupted by the Sun,” a JPL press release states.
The MRO “will scale back its observations of Mars during the conjunction period due to reduced capability to download data to Earth and a limit on how much can be stored onboard,” it adds.
“Overall, we expect to receive a smaller volume of daily data from Opportunity and none at all during the deepest four days of conjunction,” explains JPL rover mission manager Alfonso Herrera.
He explains that Opportunity will continue to relay signals to Odyssey throughout the conjunction. In order to save power, the rover has been doing that for years. Given that the orbiter is in space, it finds it a lot easier to replenish its power supplies than the dusty robot below.