Hera-JAPAN publishes observing plan for two asteroids

Hera-JAPAN has published an observing plan for the European Space Agency’s Hera mission at the Didymos–Dimorphos asteroid system. The November 2 document sets out how its cameras and two small companion spacecraft will examine the asteroids over the coming months.

The plan scheduled arrival 20–30 kilometres from the pair and the start of an initial survey for November 4, Japan Standard Time. That survey is intended to measure their mass, shape, orbital motion and rotation. The reviewed sources do not confirm that arrival was completed.

A closer survey at 8–20 kilometres is scheduled to begin on December 2. The plan then lists deployment of the Juventas CubeSat on January 16, 2027, and Milani on January 30.

Hera is following up NASA’s Double Asteroid Redirection Test, or DART, which struck Dimorphos on September 26, 2022, changing its orbit. ESA says Hera’s measurements of the impact’s effects are intended to make asteroid deflection a better-understood, repeatable technique for planetary defence.

Hera-JAPAN expects the first early-observation results to be presented at an ESA arrival event in Berlin on November 25. The observing dates remain those of the November 2 plan.