NASA has announced that soon after yesterday’s launch of the Mars Perseverance rover, the mission experienced minor issues that have hindered communication and caused the spacecraft couriering the rover to enter a "safe mode." The mission team is now working to bring the spacecraft out of its standby mode, and NASA has stated that the rover is healthy and that it is now in communication with the robotic explorer.
The Perseverance rover blasted into the skies at 4:50 am EDT (11:50 GMT) on July 30th atop a United Launch Alliance built Atlas V rocket on a mission to collect samples for an eventual return mission to Earth, and continue the hunt for life on the Red Planet. With its nerve-racking assent through Earth’s atmosphere complete, it can now undertake a seven-month journey through interplanetary space, before rendezvousing and landing on the Martian surface on February 18, 2021.
Whilst according to NASA the mission is still in good shape, the team announced that they encountered two distinct issues – neither of which were serious – soon after the rover made orbit.
First, the proximity of the spacecraft to Earth immediately after launch was saturating the ground station receivers of NASA’s Deep Space Network. This is a known issue that we have encountered on other planetary missions, including during the launch of NASA’s Curiosity rover in 2011.
Thankfully, the team was able to work through the communication issue, in part by de-tuning the ground station receivers and angling the antennas slightly away from the spacecraft so as to bring the signal within "an acceptable range," and enable lock on telemetry.
The second issue that triggered the "safe mode" involved the temperature of the courier spacecraft – also known as the cruise stage - as it orbited the Earth.
"The mission uses a liquid freon loop to bring heat from the center of the spacecraft to radiators on the cruise stage, which have a view to space," explains Wallace. "We monitor the difference in temperature between the warm inlet to the radiators and the cooler outlet from the radiators."
As Earth slipped between the spacecraft and the Sun, the outlet temperature aboard the cruise stage dropped, and the temperature differential relative to the radiator inlet triggered an alarm that forced the probe into a protective standby mode. According to the team, the temperature limits that were designed to trigger the alarm were intentionally conservative, as it's better to be safe than sorry when dealing with a US$2.4 billion piece of kit almost a decade in the making.
"Modelling by the team predicted something like this could happen during eclipse – the time when the spacecraft is in Earth’s shadow – but we could not create this exact environment for tests prior to launch," said Wallace. "Nor did we have flight data from Curiosity, because its trajectory had no eclipse."
Whilst undeniably an unpleasant surprise, the safe mode poses no risk to the spacecraft, and mission handlers are in the process of reverting the rover and its chariot back to its optimal state.
Source: NASA
