CAPSTONE – returning humans to the Moon
On 20 July 1969, around 600 million people stopped to watch humans first set foot on the Moon. The words, “That’s one small step for man, one giant leap for mankind” are forever associated with this event. In addition to leaving quite a few footprints, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin also set up experiments. The Passive Seismic Experiment Package, featured in the image below, was a forerunner to the modern space sensors we use today.
Apollo 11 lunar equipment
Astronaut Buzz Aldrin deployed a range of equipment during the first Moon landing in 1969.
Although humans were last on the Moon in 1972, we’ve never lost the desire to return, and another small NASA package called CAPSTONE is taking us one step closer.
Artemis – making a return to the Moon
NASA’s Artemis programme aims to return humans to the Moon. It’s an ambitious venture that includes powerful rockets, an orbiting outpost and a base camp on the Moon. NASA plans to use information learned on and around the Moon to take its next giant leap – sending humans to Mars.
The programme gets its name from Artemis, the mythical Greek goddess of the Moon and twin sister to Apollo. It’s a partnership with the European Space Agency, Japan Aerospace Exploration Agency, Canadian Space Agency and several commercial companies – including Aotearoa New Zealand’s Rocket Lab!
Artemis Base Camp
NASA plans to send astronauts back to the Moon. The base camp will include a cabin, rover and even a mobile home.
Rocket Lab – supporting NASA’s pathfinder mission
Giant leaps usually start with smaller steps. A very significant step took place on 28 June 2022. Rocket Lab launched the Cislunar Autonomou s Positioning System Technology Operations and Navigation Experiment (CAPSTONE) spacecraft. Despite its big name, the spacecraft is actually a small CubeSat – roughly the size of a microwave oven!
CAPSTONE CubeSat
An artist’s impression of the CAPSTONE CubeSat in orbit around the Moon.
NASA describes this 12U CubeSat as being similar in size to a microwave oven!
CAPSTONE’s role is to test a unique lunar orbit intended for use by Gateway, the lunar space station/outpost that will orbit the Moon. The orbit is known as a near-rectilinear halo orbit (NRHO). It’s an elongated orbit that will take CAPSTONE within 1,600 km of the lunar north pole on its near pass and 70,000 km from the south pole at its farthest pass. Computer simulations show NRHO to be a stable, balanced orbit that makes use of the gravity of the Earth and Moon to hold objects like Gateway in place. This type of stability offers energy savings and other benefits. CAPSTONE is the pathfinder to determine whether the simulations are accurate. In addition, CAPSTONE will conduct navigation and communication tests.
More than simply a rocket launch
Rocket Lab’s involvement with CAPSTONE went beyond the usual Electron rocket launch into low Earth orbit. It included Rocket Lab’s Lunar Photon – a second upper stage spacecraft – that separated from Electro n a few minutes after the initial launch. Lunar Photo n continued to carry CAPSTONE away from the Earth for another 6 days, providing power and communications with the satellite. One final burn took the pair to a speed of 39,500 kph, and the CubeSat separated from Lunar Photon as planned to continue on its solo trip to the Moon.
NASA had a brief scare when it lost contact with CAPSTONE due to a fault in the satellite’s software. Before contact was re-established, Rocket Lab offered a possible solution to the dilemma. Photon was on the same trajectory as CAPSTONE and had enough power to move into the intended orbit. Fortunately, CAPSTONE began sending telemetry data and the project is back on track!
CAPSTONE: Flying a new path to the Moon
This NASA video explains the CAPSTONE mission. It was produced prior to CAPSTONE’s launch from Māhia Peninsula.
Jargon alert:
CAPSTONE gets its name from Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment.
Cislunar is Latin for ‘on this side of the Moon’. It is the area of space around the Earth that extends to just beyond the Moon’s orbit.
The journey continues
Compared to the Apollo 11 mission’s 110 m Saturn V rocket, CAPSTONE is a tiny piece of equipment launched by an 18 m Electron rocket. We often imagine that a rocket launch takes a straight path to the desired location, but the tiny CubeSat is taking a much more fuel-efficient route called a ballistic lunar transfer trajectory, which uses the Sun’s gravity. Believe it or not, CAPSTONE will travel 1.3 million km before being pulled back to the Earth-Moon system. Considering the Moon is only 384,500 km from Earth, that’s a long detour! All going well, CAPSTONE will arrive in its lunar orbit on 13 November 2022.
It’s just the beginning
Rocket Lab’s successful CAPSTONE deployment is the first of several deep space missions. The company has plans to complete interplanetary missions – partnering with NASA to orbit Mars in 2024 and launching its private mission to Venus.
Related content
Investigating satellites – introduction curates a number of Hub resources on satellites and orbits.
The Satellites and orbits interactive has short videos and fact files about the functions of various satellites and orbits.
Useful links
Visit NASA’s website to learn more about Artemis missions and the tiny pathfinder CAPSTONE satellite that is leading the way.
Visit Rocket Lab’s website to read how they are supporting NASA’s CAPSTONE mission.
Read about the successful arrival at the moon of the CAPSTONE probe.
