The Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE), a small CubeSat, roughly the size of a microwave oven and weighing only 55 pounds, has evacuated the low-Earth orbit and initiated its solo journey to the Moon.
After its launch on June 28th, CAPSTONE revolved around the Earth and was connected to Rocket Lab’s Photon upper stage, which maneuvered CAPSTONE into position for its journey to the Moon. Photon’s engines flamed up seven times over the past six days at crucial moments to raise the orbit’s highest point to approximately 810,000 miles from Earth before launching the CAPSTONE CubeSat on its ballistic lunar transfer trajectory towards the Moon. The spacecraft is presently being flown by the teams at Advanced Space and Terran Orbital
Now, CAPSTONE will utilize its propulsion and the Sun’s gravity to steer the rest of the way to the Moon, a four-month mission with CAPSTONE inserting into its near rectilinear halo orbit (NRHO) around the Moon on November 13th, 2022. The gravity-driven route will significantly curtail the amount of fuel the CubeSat needs to get to its target orbit around the Moon.
NRHO is a considerably elongated orbit, found at a specific balance point in the gravitational pulls of Earth and the Moon. It provides stability towards long-term missions like Gateway and needs minimal energy to maintain. CAPSTONE’s orbit also specifies a location that is a suitable staging area for missions to the Moon and other planets. The orbit is going to bring CAPSTONE within 1,000 miles of one lunar pole on its near pass and 43,500 miles from the other pole at its top every seven days, needing less propulsion capability for spacecraft flying to and from the Moon’s surface than further circular orbits.