Hera: Assessing DART's Damage (Pre-Mission)

Hera and its cubesats at Didymos and Dimorphos. Credit: ESA

• Launch Date: October 2024
• Launch Site: Unspecified
• Launch Vehicle: Unspecified
• Mission Type: Orbiter
• Targets: Didymos & Dimorphos
• Dimensions: Unspecified
• Mass: 870 Kilograms

You can build the Hera spacecraft out of LEGO here.

The Mission

Hera is a follow up to the successful Double Asteroid Redirect Test (DART) mission. It will survey Dimorphos, and assess the damage done. Hera will autonomously navigate around the asteroid system, without direct input from mission control. The two halves of Hera were just assembled today at of the time of writing, and construction of the spacecraft is on schedule for its launch next year.

Hera mission timeline (made before Dimorphos was named in June 2020) Credit: ESA

DART's last fully transmitted image before impact. Credit: NASA/Johns Hopkins APL

Once in orbit in 2026, Hera will map out the surface topography of Dimorphos, and analyze its mass and density. We still don't know the mass of Dimorphos, and this means models of the collision are incomplete. Hera will have a gravimeter to analyse the puny gravitational field of Dimorphos. It will also take high quality images of the crater from DART, and sample its new comet-like plume.

It will survey Dimorphos, and assess the damage done, and analyze its new comet-like plume. Hera will autonomously navigate around the asteroid system, without direct imput from mission control. Along for the mission are two cubesats to help it analyse Dimorphos in further detail. These are named Milani and Juventas. Milani will take spectroscopic observations of the surface compostion of Dimorphos, and Juventas will make record-breaking radar soundings.

Credit: ESA

The Targets

Didymos with North facing up. Credit: NASA/Johns Hopkins APL

• Date Discovered: April 11, 1996
• Designation: 65803 Didymos (1996 GT)
• Class: Apollo [NEO]
• Radius: 390 Meters
• Rotational Period: 2.26 Hours
• Orbital Period: 768.99 Days (2.11 Years)

Dimorphos with North facing up. Credit: NASA/Johns Hopkins APL

• Date Discovered: November 20, 2003
• Designation: I Dimorphos
• Class: Apollo [NEO]
• Radius: 81.5 Meters
• Orbital Period Pre-Impact: 11 hours and 55 Minutes
• Orbital Period Post-Impact: 11 hours and 22 Minutes