Mars Cube One

Mars Cube One. Mars Cube One, commonly known as MarCO, was a pair of briefcase-sized CubeSat spacecraft that served as a pioneering technology demonstration for NASA. Launched as secondary payloads alongside the InSight Mars lander, their primary mission was to relay real-time telemetry during InSight's critical entry, descent, and landing phase to Earth. The successful operation of the twin MarCO satellites proved the viability of miniaturized, low-cost spacecraft for deep space exploration.

Overview

The MarCO mission was developed by a team at the Jet Propulsion Laboratory in collaboration with several academic and industry partners. As the first CubeSats to operate beyond Earth orbit, their objective was to validate key technologies for interplanetary smallsats, including a compact radio, a folding high-gain antenna, and an innovative propulsion system using cold gas thrusters. The mission aimed to demonstrate a new paradigm for providing real-time communications support during critical events at other planets, supplementing the primary data relay provided by larger assets like the Mars Reconnaissance Orbiter. This approach was seen as a potential model for future missions to Mars, Venus, or asteroids, where dedicated, risk-tolerant spacecraft could enhance mission flexibility.

Development and design

Each MarCO spacecraft was a 6U CubeSat, a standardized form factor measuring approximately the size of a briefcase. The design incorporated several commercial off-the-shelf components adapted for the harsh environment of deep space. Key innovations included an Iris deep-space transponder, a compact X-band radio developed at JPL that provided a direct link to the Deep Space Network on Earth. For propulsion, the satellites used a cold gas system fueled by R236fa, a refrigerant, for attitude control and trajectory corrections. Perhaps the most distinctive feature was the deployable X-band high-gain antenna, a flat-panel design that unfolded like a cardboard box to provide the necessary gain for communication across millions of kilometers. The spacecraft's avionics and power systems were also miniaturized, drawing on advancements from the growing small satellite community.

Mission profile and operations

MarCO-A and MarCO-B launched on May 5, 2018, from Vandenberg Space Force Base aboard an Atlas V rocket, sharing the ride with the InSight lander. After separation, the two CubeSats independently navigated their way to Mars, performing several trajectory correction maneuvers. On November 26, 2018, as InSight began its descent through the Martian atmosphere, the MarCO satellites positioned themselves to serve as "bent pipe" relays. They received InSight's UHF signal during its "seven minutes of terror," immediately reformatting and transmitting the data to Earth at X-band frequencies. Both spacecraft successfully performed this relay, with data arriving on Earth in near-real-time, approximately eight minutes later. Following this primary task, the MarCO team conducted extended operations, attempting to image Mars and test systems further before the satellites eventually fell silent in early 2019 as they traveled beyond the planet.

Results and legacy

The MarCO mission was an unqualified success, achieving all its primary objectives and demonstrating that CubeSats could survive and operate effectively in deep space. The real-time relay of InSight's landing data proved the concept of using small, dedicated communications relays for critical mission events. The technologies validated by MarCO have directly influenced subsequent NASA missions, most notably the Lunar Flashlight and the upcoming EscaPADE mission to study the Martian magnetosphere. The mission's success has spurred significant interest within the global space community, encouraging the development of more ambitious interplanetary small satellite projects by agencies like the Japan Aerospace Exploration Agency and the European Space Agency. MarCO's legacy is a paradigm shift, proving that low-cost, rapidly developed spacecraft can play a vital role in the exploration of the Solar System.

Category:NASA spacecraft Category:CubeSats Category:Mars spacecraft Category:2018 in spaceflight Category:Spacecraft launched in 2018