A tiny moon-bound spacecraft will wait at least a few more days to launch.
Liftoff for the CAPSTONE mission, short for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment, has been pushed back four days to May 31 at the earliest, NASA announced this week.
“We will continuously assess the date of the first target launch attempt during the launch window, which extends through June 22,” agency officials wrote Wednesday, May 11 on its blog for the Artemis Moon program. The message did not specify why the launch was slightly delayed.
The microwave-sized CAPSTONE spacecraft will launch from New Zealand aboard a Rocket Lab Electron rocket with a Lunar Photon upper stage. Its mission is to verify the stability of a near-rectilinear halo orbit (NRHO) around the moon, by modeling what Gateway – the small lunar-orbiting space station that is a key part of the Artemis plan – will need to follow with astronauts on board.
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The planned orbit will bring CAPSTONE within 1,000 miles (1,600 kilometers) of a lunar pole at its closest point, providing access to the south pole. It is the primary target of crewed Artemis missions, given the likely presence of water ice in the permanently shadowed polar craters.
At its highest altitude, CAPSTONE will hover 43 times higher at 43,500 miles (70,000 km). The advantage of such an orbit is that future spacecraft to and from the lunar surface at the south pole will not need to fly as high to meet Gateway, but the halo orbit has not yet been tested by other spacecraft.
To complicate matters, the moon has known mascons (mass concentrations) that can disrupt orbits. NASA is therefore looking for an inexpensive test before sending the much more expensive Gateway into such orbit.
CAPSTONE’s secondary mission is to evaluate spacecraft navigation and communication systems with NASA’s Lunar Reconnaissance Orbiter, which has circled the moon since 2009. CAPSTONE was originally scheduled to fly in 2021, but the mission was delayed from then on due to COVID-related issues.