NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header




The Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) is a 12U CubeSat designed to go into a near-rectilinear halo orbit around the Earth to closely match the Moon's orbit. The primary objectives are to demonstrate spacecraft-to-spacecraft navigation and to enter this orbit to verify its feasibility, to gain experience for future flights planning to use similar orbits, and as a precursor to the possible Gateway lunar orbiting outpost.

Spacecraft and Subsystems

CAPSTONE is a 12U CubeSat, 20 x 20 x 30 cm, with two solar panel wings to supply power. Total mass of the spacecraft is 25 kg. A deployable dish antenna is used for communication. Propulsion is provided by a monopropellant hydrazine reaction control system. It uses eight 0.25 N thrusters, four for translational thrust and four for rotational thrust. It will carry approximately 3.2 kg of hydrazine in a machined aluminum tank.

Mission Profile

Launch is currently scheduled for no earlier than 20 October 2021. It will be launched on a Rocket Lab Electron booster from NASA Wallops Flight Facility into a 250 km circular Earth orbit, the Photon upper stage will perform a series of orbit-raising maneuvers to put CAPSTONE into a trans-lunar trajectory. CAPSTONE will travel 3 months under its own propulsion. It will then enter a near-rectilinear halo orbit, in which the spacecraft orbits the Earth along with the Moon, and will come within about 1600 km of one pole and then 7 days later pass roughly 70,000 km above the other pole. It will continue in this orbit for at least six months, testing communications with the Lunar Reconnaissance Orbiter (LRO), already in orbit around the Moon, and ground stations on Earth. It will also use data from communications with LRO to determine its position.

Image credit: Rocket Lab

Alternate Names

    Facts in Brief

    Launch Date: 2021-10-20
    Launch Vehicle: Electron
    Launch Site: Wallops Island, United States
    Mass: 25 kg

    Funding Agency

    • National Aeronautics and Space Administration (United States)


    • Planetary Science

    Additional Information

    Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



    NameRoleOriginal AffiliationE-mail
    Dr. Elwood AgasidProgram ManagerNASA Ames Research
    [] NASA Logo -