There are two identical satellites tracking the InSight through space, both from the CubeSat family. Internally nicknamed Wall-E and Eva, after the Pixar characters, the satellites are officially known as MarCO-A and MarCO-B. Their mission is to document the journey of the mission and, should they survive the trip, the lander’s entry into the Martian atmosphere.
The photo shown by NASA was taken by MarCO-B’s wide-angle camera situated on the deck of the CubeSat. On either side of the image, you can see parts of the high-gain antenna of the satellite.
"We've been waiting six months to get to Mars," said in a statement Cody Colley, MarCO's mission manager at JPL. "The cruise phase of the mission is always difficult, so you take all the small wins when they come. Finally seeing the planet is definitely a big win for the team."
The CubeSat family started life as a tool for NASA to teach engineering students how to build spacecraft. Because they are the size of briefcases, the machines have been chosen to become assistance tools for the various missions NASA plans in the future, including the building of a lunar-orbital space station.
The mission InSIght will have on the Red Planet is to study Mars' deep interior using seismology and other geophysical measurements, including an ultra-sensitive seismometer and a heat-flow probe.