Archive for November 16, 2021

11/16/2021 – Ephemeris – How China retrieved a sample from the Moon, and what Chang’e 5 is up to next

November 16, 2021 Comments off

This is Ephemeris for Tuesday, November 16th. Today the Sun will be up for 9 hours and 31 minutes, setting at 5:13, and it will rise tomorrow at 7:42. The Moon, 3 days before full, will set at 5:49 tomorrow morning.

China’s Chang’e sample return mission of late last year was quite a feat. The spacecraft had an orbiter that orbited the Moon, and sent a lander with an ascent rocket. After the lander secured its samples, it put them in the ascent rocket, which launched back up to the orbiter. The samples were placed in a reentry capsule attached to the orbiter, which left the Moon’s orbit and headed back to the Earth. Near Earth, it ejected the reentry capsule and swung past Earth and headed out to the Earth-Sun Lagrangian point 1 between the Earth and Sun. There are already several satellites in halo orbits around L1, because it’s a great spot to be to study the Sun unobstructed by the Earth, and detect Coronal Mass Ejections (CMEs) about an hour before they reach Earth. NASA, NOAA and the European Space Agency all have satellites out there.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.


Chang'e 5 Descent Capsule

Chang’e 5 Descent Capsule lands. It looks like a miniature Russian Soyuz Descent capsule. Credit Chinese Space Agency via Global Times.

Earth-Sun Lagrangian Points

Earth-Sun Lagrangian Points. These are where a small body can stay. L1, 2 and 3 are unstable, so some little effort is needed to keep a spacecraft near there. L4 and L5 are stable. Source: Wikimedia Commons, Xander89. Click to enlarge.