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Capstone graphic 13feb20 0.jpg
Illustration of the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE).
NamesCislunar Autonomous Positioning System Technology Operations and Navigation Experiment
Mission typeTechnology demonstration
OperatorAdvanced Space[1]
COSPAR ID2022-070A Edit this at Wikidata
SATCAT no.52914Edit this on Wikidata
Mission durationPlanned: 10 Months Elapsed: 11 months and 6 days
Spacecraft properties
Spacecraft type12U CubeSat
ManufacturerAdvanced Space (management)
Tyvak Nano-Satellite Systems (bus)
Stellar Exploration, Inc (propulsion)
Launch mass25 kg (55 lb)[2][3]
Start of mission
Launch date28 June 2022, 09:55 UTC[2]
RocketElectron/Photon HyperCurie
Launch siteMahia, LC-1B[4]
ContractorRocket Lab
Moon orbiter
Orbital insertion14 November 2022, 00:38 UTC
OrbitsNear-rectilinear halo orbit (NRHO)[3]
Orbital parameters
Periselene altitude1,500 km (930 mi)
Aposelene altitude70,000 km (43,000 mi)
InclinationElliptic polar orbit

CAPSTONE (Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment) is a lunar orbiter that will test and verify the calculated orbital stability planned for the Lunar Gateway space station. The spacecraft is a 12-unit CubeSat that will also test a navigation system that will measure its position relative to NASA's Lunar Reconnaissance Orbiter (LRO) without relying on ground stations. It was launched on 28 June 2022, arrived in lunar orbit on 14 November 2022, and was scheduled to orbit for six months. On 18 May 2023, it completed its primary mission to orbit in the near-rectilinear halo orbit for six months, but will stay on this orbit, continuing to perform experiments during an enhanced mission phase.[5]


The Lunar Gateway is an in-development space station being planned by several national space agencies since at least 2018, including NASA, European Space Agency (ESA) and Canadian Space Agency (CSA). The Gateway is planned to be placed in a novel lunar orbit that until 2022 had not been used, where it is expected to serve as a communications hub, science laboratory, short-term habitation module, and holding area for rovers and other robots.[6] Gateway is slated to play a major role in NASA's Artemis program.

Computer simulations indicated that this particular orbit – a near-rectilinear halo orbit (NRHO) – offers long-term stability with low propellant requirements for orbital station-keeping,[7] by using a precise balance point in the gravities of Earth and the Moon that offers a stable trajectory.[8]

The main objective of the CAPSTONE mission is to verify the theoretical orbital stability simulations for the Gateway with an actual spacecraft.[9][8][10] CAPSTONE is the first spacecraft to operate in an NRHO.[10][8] The spacecraft is also testing a navigation system called Cislunar Autonomous Positioning System (CAPS),[11] which measures its position relative to NASA's Lunar Reconnaissance Orbiter (LRO) without relying on ground stations.[8]


The orbiter is a 12-unit CubeSat.[10][8][9] The US$13.7 million contract was awarded to a private company called Advanced Space, Boulder, Colorado, on 13 September 2019 through a federal Small Business Innovation Research (SBIR) contract.[10][8] Advanced Space handled overall project management and some of the spacecraft's key technologies, including its CAPS positioning navigation system,[11] while Tyvak Nano-Satellite Systems, Irvine, California, developed and built the spacecraft bus,[8] and Stellar Exploration, Inc developed its propulsion systems[12] that used Hydrazine.[13]


The Electron rocket carrying CAPSTONE seen lifting off from Rocket Lab's Launch Complex in Mahia, New Zealand
CAPSTONE Launch to the Moon
video icon - NASA broadcast (YouTube)

NASA announced on 14 February 2020 that CAPSTONE would be launched aboard a Rocket Lab Electron booster from the company's new launch site at the Mid-Atlantic Regional Spaceport (MARS), Wallops Island, in Virginia.[3] The launch was scheduled for October 2021 but was subsequently delayed and moved to launch from Mahia, LC-1 in New Zealand.[4][14] The launch contract with Rocket Lab has a value of US$9.95 million, according to NASA.[3]

Rocket Lab's new launch pad in Virginia, designated Launch Complex 2, was completed in 2019 and was hoped to be ready to support launches by 2021. The company said the new facility would principally support Electron missions with U.S. government payloads. However, certification of the Autonomous Flight Termination System (AFTS) took longer than anticipated, resulting in the launch site being changed to Mahia.[4]

CAPSTONE launched on 28 June 2022. After separating from the second stage, the Rocket Lab's Photon kick stage lifted the orbital apogee into a lunar-transfer orbit over six days by firing the HyperCurie bipropellant engine at perigee six times followed by the trans-lunar injection (TLI) burn, after which the CAPSTONE spacecraft was deployed on its journey to the Moon.[15]

On 5 July 2022, NASA lost contact with the spacecraft shortly after separation from Photon and stated their intention to recover two-way communication with the spacecraft and continue the mission.[16] On 6 July, mission operators re-established contact with the spacecraft.[17] By 30 September, CAPSTONE was "power positive" and on a stable trajectory towards the Moon while the mission operators worked to regain orientation control of the spacecraft.[18] The root cause of the problem was narrowed to a valve on a thruster that is probably partially open, which thus produces thrust whenever the propulsion system is pressurized. On 7 October, the team uploaded recovery commands, stopped the spin, and regained full 3-axis attitude control. It remained on track to insert into its targeted orbit.[19]

Ballistic lunar transfer[edit]

CAPSTONE used a ballistic transfer to the Moon instead of a more conventional direct Hohmann transfer.[20] While trajectories of this type take much longer to reach their destination (about four months in this case, compared to about three days using a traditional direct transfer) they significantly reduce the propulsion requirements, which can increase the delivered mass (about 10-15% more mass).[21] After being ejected from Earth orbit by a series of burns of the Photon stage, the spacecraft reached a distance of about 1.5 million kilometers, where perturbations from the Sun became important.[20] It then fell back towards the Earth, intercepting the Moon's orbit and finally entering NRHO around the Moon on 14 November 2022.


Following a three-month trip to the Moon after launch, the CAPSTONE lunar satellite spent six months collecting data during this demonstration, flying within 1,000 miles (1,600 km) of the Moon’s North Pole on its near pass and 43,500 miles (70,000 km) from the South Pole at its farthest.[3][22]

Animation of CAPSTONE
Around the Earth
Around the Moon - Frame rotating with Moon - Front view
Around the Moon - Frame rotating with Moon - Side view
  Earth ·   CAPSTONE ·   Moon

See also[edit]


  1. ^ "CAPSTONE". Advanced Space. Retrieved 15 November 2022.
  2. ^ a b "CAPSTONE". NASA Space Science Data Coordinated Archive. Retrieved 9 February 2023.
  3. ^ a b c d e Clark, Stephen (15 February 2020). "NASA picks Rocket Lab to launch lunar CubeSat mission". Spaceflight Now. Archived from the original on 8 May 2021. Retrieved 18 March 2020.
  4. ^ a b c "Rocket Lab to Launch NASA Funded Commercial Moon Mission from New Zealand" (Press release). Rocket Lab. 6 August 2021. Archived from the original on 8 August 2021. Retrieved 8 August 2021.
  5. ^ "CAPSTONE Takes Moon Shot, Successfully Tests Navigation Technology". NASA. Retrieved 23 May 2023.
  6. ^ "Competition Seeks University Concepts for Gateway and Deep Space Exploration Capabilities". NASA. 11 September 2018. Archived from the original on 17 June 2019. Retrieved 19 September 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  7. ^ "Angelic halo orbit chosen for humankind's first lunar outpost". ESA. 18 July 2019. Archived from the original on 24 June 2021. Retrieved 18 March 2020.
  8. ^ a b c d e f g Foust, Jeff (16 September 2019). "NASA cubesat to test lunar Gateway orbit". SpaceNews. Retrieved 18 March 2020.
  9. ^ a b Torbet, Georgina (15 September 2019). "NASA chooses a CubeSat project to test orbit route around the moon". Digital Trends. Archived from the original on 24 June 2021. Retrieved 18 March 2020.
  10. ^ a b c d "Advanced Space selected to develop CubeSat pathfinder mission". Aerospace Technology. 16 September 2019. Archived from the original on 24 June 2021. Retrieved 18 March 2020.
  11. ^ a b "Cislunar Autonomous Positioning System (CAPS)". Advanced Space. Archived from the original on 24 June 2021. Retrieved 16 September 2019.
  12. ^ Hall, Loura (31 July 2020). "What is CAPSTONE?". NASA. Archived from the original on 3 August 2020. Retrieved 4 August 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  13. ^ Tabor, Abigail (22 March 2021). "Innovative Propulsion System Will Study Moon Orbit for Artemis". NASA. Retrieved 17 October 2022.
  14. ^ David, Leonard (25 August 2021). "CAPSTONE, a small cubesat bound for the moon, is preparing for an October launch". Archived from the original on 27 August 2021. Retrieved 27 August 2021.
  15. ^ Foust, Jeff (4 July 2022). "CAPSTONE heads to the moon". SpaceNews. Retrieved 5 July 2022.
  16. ^ Shields, Todd (5 July 2022). "Capstone Spacecraft on Moon Mission Loses Contact, NASA Says". Bloomberg. Retrieved 5 July 2022.
  17. ^ "CAPSTONE Update: Communications Re-Established". 6 July 2022. Retrieved 6 July 2022.
  18. ^ "CAPSTONE Team Continues Work Towards Spacecraft Recovery". 30 September 2022. Retrieved 30 September 2022.
  19. ^ "CAPSTONE Team Stops Spacecraft Spin, Clearing Hurdle to Recovery – Artemis". Retrieved 8 October 2022.
  20. ^ a b "CAPSTONE Uses Gravity on Unusual, Efficient Route to the Moon". NASA. 19 May 2022.
  21. ^ "Ballistic Lunar Transfers to Near Rectilinear Halo Orbit". Advanced Space, LLC. Retrieved 5 July 2022.
  22. ^ "CAPSTONE Launches to Test New Orbit for NASA's Artemis Moon Missions". 28 June 2022.