Engineer Joel Steinkraus uses sunlight to test the solar arrays on one of Mars Cube One (MarCO) spacecraft at NASA's Jet Propulsion Lab.
Two briefcase-sized satellites launched from Vandenberg Air Force Base as part of a mission to Mars now appear to be lost in space.
More than 300 million miles from Earth, the two satellites “seem to have reached their limit” according to scientists with the Jet Propulsion Laboratory in Pasadena.
The twin spacecraft, known collectively as Mars Cube One, or MarCO, were part of NASA’s InSight mission to the Red Planet, launched last May. The mini-satellites, called CubeSats, were nicknamed EVE and WALL-E in honor of characters from the Pixar film, WALL-E. They were the first attempt by JPL to send a CubeSat to another planet, rather than simply orbiting Earth.
The two satellites, which cost $18.5 million, survived the arduous six-month trip to Mars, and worked as communications relays during InSight’s November landing on the planet. They beamed back data with details about every stage of the main satellite’s descent onto the Martian surface. WALL-E sent images of Mars, while EVE conducted radio science processes.
WALL-E was last heard from on Dec. 29, while EVE sent its last communications on Jan. 4. JPL officials believe WALL-E is more than 1 million miles beyond Mars, while EVE appears to have reached more than 2 million miles past the Red Planet.
That’s a staggering feat, considering the MarCO’s design had a stowed size of roughly 14 inches by 9 inches by 5 inches. And, on top of that, they travelled through the vastness of space weighing just 30 pounds each.
Regardless of their fate, JPL says MarCO pushed the “limits of experimental technology.”
In evaluating why the satellites seem to have been lost, JPL scientists noted that WALL-E has a leaky thruster, and attitude control issues could have caused them to wobble, while also losing the ability to send and receive commands.
The CubeSats also have brightness sensors, which enable them to stay pointed at the Sun, and to recharge their batteries. Because they are in orbit around the Sun, they will move further away from the brightness source as the month passes.
“The farther they are, the more precisely they need to point their antennas to communicate with Earth,” according to JPL.
The mission’s scientific team will attempt to reestablish contact with the CubeSats in the summer, when the spacecraft start moving toward the Sun again.
JPL suggests “it’s anyone’s guess” whether the CubeSat’s batteries and other equipment will survive that long in space. MarCO is still considered a “spectacular success,” no matter its fate.
“This mission was always about pushing the limits of miniaturized technology and seeing just how far it could take us,” said Andy Klesh, the mission’s chief engineer at JPL, in a statement. “We’ve put a stake in the ground. Future CubeSats might go even farther.”
A number of the critical spare parts for each MarCO will be used in other CubeSat missions, including their experimental radios, antennas and propulsion systems.
More small spacecraft are on the way. NASA is set to launch a variety of new CubeSats in coming years.
“There’s big potential in these small packages,” said John Baker, the MarCO program manager at JPL, in a release. “CubeSats — part of a larger group of spacecraft called SmallSats — are a new platform for space exploration that is affordable to more than just government agencies.”
