Before the pair of briefcase-sized spacecraft known collectively as MarCO launched a year ago, their success was measured by survival: If they were able to operate in deep space at all, they would be pushing the limits of experimental technology.
The MarCO CubeSats before being stowed and prepared for launch.
"This mission was always about pushing the limits of miniaturised technology and seeing just how far it could take us", said Andy Klesh, the mission's chief engineer at NASA's Jet Propulsion Laboratory in California, which built the CubeSats.
WALL-E, which last communicated with Earth on December 29, is slightly more than one million miles (1.6 million kilometers) beyond the Red Planet while EVE, which last contacted Earth on January 4, is close to two million miles (3.2 million kilometers) past Mars. The mission, known as MarCO, was a foray into using CubeSats for interplanetary communications.
"MarCO was there to relay information back from InSight in real time, and we did that extraordinarily well", said Andy Klesh, MarCO chief engineer, at a press conference at JPL immediately after the successful InSight landing November 26. "We've put a stake in the ground". Inside the dome, the seismometer is also contained in a titanium, vacuum-sealed container, the combination of which helps insulate the instrument even further from environmental hazards.
Nasa has several theories about why it has lost contact with the pair - none of which involve the interference of aliens. Or maybe they both can't point their solar panels toward the Sun to power up, and have run out of juice. On top of that, the CubeSats' batteries may be long dead and fail to recharge by the time they are bathed in full sunlight once more. The satellites are still receding from the Sun, and their greater distance requires more precision in aiming their antennas toward Earth. Attitude-control issues could be causing them to wobble and lose the ability to send and receive commands. The agency knows of a problem Wall-E has with a leaky thruster, and there's also doubt the two are capable of correctly pointing their antennas towards Earth as they go deeper into space.
The systems used for the MarCOs are produced by commercial companies and are likely compatible with various other types of CubeSats.
After that, the team said if they made it that far it would already be a major success.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science.
With over seven years of experience in online journalism, Vadim is passionate about everything related to science and the environment.