NASA’s Mars CubeSats notch another spaceflight first

If all goes according to plan, the twin communications-relay Mars Cube One (MarCO) spacecraft will allow NASA to quickly transmit status information about InSight as it lands on Mars on November 26, 2018.

The CubeSats, called MarCO-A and MarCO-B made history by being the first-ever interplanetary CubeSats and met another milestone by acing some critical communications tests said John Baker, program manager for planetary smallsats at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

JLP is heading up the $18.5 million MarCO mission as a technology demonstration using standardized small spacecraft and modular use of off-the-shelf technologies.

“Our broadest goal was to demonstrate how low-cost CubeSat technology can be used in deep space for the first time,” Baker said in a statement. “With both MarCOs on their way to Mars, we’ve already traveled farther than any CubeSat before them.”

This NASA artist's concept from August 2015 and released on December 22, 2015 depicts NASA's InSight Mars lander fully deployed for studying the deep interior of Mars

, NASA/JPL-Caltech/AFP

Making a course correction maneuver
A CubeSat has never had to make a course correction before, and in order for the tiny spacecraft to complete their mission, several trajectory corrections will have to be made before they reach the Red Planet.

Over the past week, the twin MarCO cubes have completed a first for any CubeSats, by successfully pulling off a trajectory correction maneuver by firing their propulsion systems.

MarCO-A completed the trajectory correction maneuver (TCM) with relative ease, but MarCO-B was a bit sluggish in making its course correction due to a leaky thruster valve that engineers have been monitoring for the past several weeks.

The image, which shows both the CubeSat’s unfolded high-gain antenna at right and the Earth and its moon in the center, was acquired by MarCO-B on May 9. (Earth is the little blue dot just off-center in the image)>

JPL

The leak itself causes small trajectory changes, and these small nudges have been factored in by NASA engineers for just such an issue. MarCO-B can still perform a trajectory correction maneuver and follow it’s twin as they head for Mars.

“We’re cautiously optimistic that MarCO-B can follow MarCO-A,” said Joel Krajewski of JPL, MarCO’s project manager, reports Phys.Org. “But we wanted to take more time to understand the underlying issues before attempting the next course-correction maneuver.”

A big communications experiment
Should the CubeSats make it all the way to Mars, which will be an historic first, they will then attempt to relay data to Earth about InSight’s landing. During InSight’s entry, descent, and landing (EDL) operations, the lander will transmit information on the UHF radio band to NASA’s Mars Reconnaissance Orbiter (MRO) flying overhead.

An artist’s illustration of one of NASA’s Mars Cube One (MarCO) cubesats.

NASA/JPL

MRO will forward EDL information to Earth using a radio frequency in the X band, but it cannot simultaneously receive information on one band while transmitting on another.

The MarCO’s have softball-size radios providing both UHF (receive only) and X-band (receive and transmit) functions capable of immediately relaying information received over UHF. So if this experiment succeeds, it will open the door to a “bring-your-own” communications relay option for use by future Mars missions.

Here’s a bit of trivia on the CubeSats, just in case anyone asks if you know their nicknames. According to Space.com, MarCO-A and MarCO-B are nicknamed “Wall-E” and “Eva” after the adorable (but fictional) robots from Disney’s animated film “Wall-E.”

Their name is inspired by the titular robot, which uses a fire extinguisher to fly through space in the film. Interestingly, the MarCO spacecraft use a compressed gas called R236FA as a propellant, the same kind of gas used in some fire extinguishers. How cool is that?