06/10/2022 – Ephemeris – The first Artemis mission: CAPSTONE

This is Bob Moler with Ephemeris for Friday, June 10th. Today the Sun will be up for 15 hours and 30 minutes, setting at 9:27, and it will rise tomorrow at 5:56. The Moon, 3 days past first quarter, will set at 3:52 tomorrow morning.

Launching, perhaps, as soon a Monday is the CAPSTONE Mission, which is part of the Artemis program to send the next man and first woman to the Moon. The Capstone mission is to check out the special near rectilinear halo orbit the Lunar Gateway space station, and the Human Landing Craft will be in when the Orion spacecraft arrives before landing. CAPSTONE is, of course, an acronym that explains its purpose, to achieve and navigate itself into this near rectilinear halo orbit. CAPSTONE is basically a CubeSat made of 12 4 by 4 inch (12 100 mm by 100 mm) cubes. It will be launched by Rocket Lab from New Zealand on their Electron rocket with their Proton upper stage. It will take 3 months to reach the Moon.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Artist’s impression of the CAPSTONE spacecraft at perilune, the closest point in its orbit, over the north pole of the Moon.

CAPSTONE’s near rectilinear halo orbit of the Moon, which precesses to keep face on to the Earth during the lunar orbit of the Earth.

08/16/2021 – Ephemeris – The first Artemis mission (maybe) – CAPSTONE

This is Ephemeris for Monday, August 16th. Today the Sun will be up for 13 hours and 59 minutes, setting at 8:46, and it will rise tomorrow at 6:47. The Moon, 1 day past first quarter, will set at 1:13 tomorrow morning.

Tonight’s Moon is a great one to view with a small telescope. Speaking of the Moon, a company called Rocket Lab will be launching the first Artemis program mission, later this year, in preparation to land crews back on the Moon. They are launching a small CubeSat to orbit the Moon in a Near Rectilinear Halo Orbit which always faces the Earth and never goes behind the Moon. To test whether all the mathematical calculations for the orbit actually work in real life. The satellite is called CAPSTONE (another tortured NASA acronym*). It will be launched from New Zealand, Rocket Lab’s main launch site first into a polar orbit before heading to the lunar orbit, taking several months to get there.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

* Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment. Told ya. Cislunar space is a spherical volume of space centered on the Earth, whose radius is the Moon’s distance. Beyond that is interplanetary space.

Addendum

Rocket Lab had been planning to launch the CAPSTONE satellite from Wallops Island, Virginia, but approval was taking too long, so they moved the launch to their New Zealand launch site instead.

NASA CAPSTONE* pathfinder for gateway orbit is to be launched late this year by Rocket Lab to prove out the near rectilinear orbit for the Lunar Gateway.