'I'll Be Signing Off Here Soon': NASA's InSight Lander Sends What May Be Its Last Image Of Mars

NASA InSight: For the last few months, InSight's power levels have been declining. Before signing off, the lander has sent what may be its last image of the Red Planet.

NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Lander has captured what could be its last image of Mars, and is preparing to sign off because its power is very low. For the last few months, InSight's power levels have been declining. In November this year, NASA said in a statement that it is preparing to say 'farewell' to InSight, whose end is expected soon. 

On Tuesday, December 20, a Twitter post made on behalf of InSight said: "My power’s really low, so this may be the last image I can send. Don’t worry about me though: my time here has been both productive and serene. If I can keep talking to my mission team, I will – but I’ll be signing off here soon. Thanks for staying with me."

Before signing off, the lander has sent what may be its last image of the Red Planet. Ever since it landed on Mars on November 26, 2018, InSight has captured spectacular images of the Red Planet, revealing mysteries about its interior. 

NASA's preparations ahead of bidding InSight farewell

NASA started taking steps to store InSight data and make it accessible to researchers worldwide, several weeks ahead of the spacecraft's likely end. InSight has been revolutionary in terms of providing information about the interior layers of Mars, the planet's liquid core, weather on Mars, and quake activity on the Red Planet. 

France's Centre National d'Études Spatiales (CNES) had provided InSight's seismometer, which has detected more than 1,300 marsquakes since the touchdown of the lander on the Martian surface in November, 2018. The seismic waves from marsquakes change as they travel through the Red Planet. These observations provide a glimpse into Mars' interior and a better understanding of how all rocky worlds, including Earth and the Moon, form. 

How the InSight team managed the lander's power

Since InSight had little power remaining this summer, the mission control team turned off all of the lander's science instruments to keep the seismometer running. InSight has a fault protection system that automatically shuts down the seismometer if the system detects that the lander's power generation is dangerously low. However, the team turned off the fault protection system themselves. 

Bruce Banerdt of NASA's Jet Propulsion Laboratory (JPL), the mission's principal investigator, said in the statement that InSight's power had come down to less than 20 per cent of its original generating capacity, which meant that NASA could not afford to run the instruments around the clock. 

The team recently turned off the seismometer altogether in order to save power, because a regional dust storm added dust to the lander's solar panels. After the storm was over, the seismometer was turned on so that it could collect data again. The seismometer has an array of sensors, but only the most sensitive were still operating, according to Liz Barrett, who leads science and instrument operations for InSight at JPL.

InSight’s twin, ForeSight, to be packed up

NASA is also preparing to pack up ForeSight, a full-size replica of InSight, often regarded as the Mars lander's twin. ForeSight is the full-size engineering model of InSight in JPL's In-Situ Instrument Laboratory, and has been used by scientists to practise how they would place science instruments on the Martian surface with the lander's robotic arm, develop ways to reduce noise picked up by the seismometer, and test techniques to get InSight's heat probe into the sticky Martian soil. 

Banerdt said the InSight team will be packing up ForeSight with "loving care", and place it in storage. 

When will NASA declare the end of InSight's mission?

When InSight misses two consecutive communication sessions with the spacecraft orbiting Mars, which is a part of the Mars Relay Network, NASA will declare the mission over. However, this will be done only if the cause of the missed communication is the lander itself, according to network manager Roy Gladden of JPL.

No heroic measures will be taken to re-establish contact with InSight. NASA believes that a mission-saving event, such as a strong gust of wind that cleans the solar panels off, is considered unlikely. 

Most interesting science results from InSight

Some of the most interesting science results obtained using observations from InSight include the detection of the first quake on a different planet, gathering new information about Mars' three major layers, namely crust, mantle and core, discovering meteoroid impacts on the Red Planet, uncovering a layer of water ice below the Martian surface, finding magnetic 'ghosts' from an old electrical field, and studying weather data, among others.