09/12/2022 – Ephemeris – The Dart Mission hits its asteroid in two weeks

This is Bob Moler with Ephemeris for Monday, September 12th. Today the Sun will be up for 12 hours and 40 minutes, setting at 7:59, and it will rise tomorrow at 7:19. The Moon, 2 days past full, will rise at 9:16 this evening.

Two weeks from today, a small satellite will smash into a small asteroid ion an attempt to change its orbit. The spacecraft and the name of the NASA mission is DART (Double Asteroid Redirection Test). At 7:14 pm Monday, September 26th, the DART spacecraft will crash into a tiny 525-foot diameter asteroid that’s orbiting a larger asteroid. The target is Dimorphos that is orbiting Didymos. Dimorphos is orbiting Didymos at the slow pace of four tenths of a mile an hour, taking 11.9 hours to orbit it once. The DART spacecraft hit should change that a bit. A cube sat, launched by DART, should witness the event. Radio telescopes using radar should see any effect on the velocity of Dimorphos, to see if it worked.

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

Schematic of the DART mission shows the impact on the moonlet of asteroid (65803) Didymos. Post-impact observations from Earth-based optical telescopes and planetary radar would, in turn, measure the change in the moonlet’s orbit about the parent body. The DART spacecraft is not to scale with the asteroids. Click on the image to enlarge it. Credits: NASA/Johns Hopkins Applied Physics Lab.

Dart and asteroids to scale with terrestrial landmarks. Click on the image to enlarge it. Credit: NASA/JHUAPL