It’s an exciting day for NASA. The agency’s twin Mars Cube One (MarCO) mini-spacecraft have launched from dispensers mounted on the aft bulkhead carrier of the Atlas V Centaur second stage. Designed and built by NASA’s Jet Propulsion Laboratory in Pasadena, California, MarCO will be the first test of CubeSat technology in deep space. They are designed to test new communications and navigation capabilities for future missions and may provide real-time communication relay to cover the entry, descent and landing of InSight on Mars.