Mission

Hera

ESA's mission to the Didymos double asteroid, surveying the result of NASA's DART impact so that deflection can be repeated with confidence.

Hera is the European Space Agency's planetary defense mission to the Didymos double asteroid. It makes a detailed survey of Dimorphos, the moonlet NASA's DART spacecraft struck in 2022, to turn that single test into a well-understood and repeatable technique.[1] It is the first probe to rendezvous with a binary asteroid.[1]

The mission

Hera launched on 7 October 2024 from Cape Canaveral Space Force Station in Florida.[2] A flyby of Mars in March 2025 bent its path toward Didymos.[3] In October 2026 the spacecraft began a series of braking burns to slow down and match the speed of the asteroids, and ESA planned its arrival at Didymos for November 2026, a month earlier than first planned.[2][3]

At Didymos, Hera's work centers on the crater DART left and on a precise measurement of the mass of Dimorphos.[4] It navigates autonomously, keeping the asteroids in view without commands from Earth.[3]

Two small companions

Hera carries two CubeSats about the size of suitcases, Milani and Juventas, which are released near the asteroids to make their own close-up studies.[3] Juventas carries a radar to make the first survey of an asteroid's interior, and it is planned to attempt a landing on Dimorphos; no CubeSat has landed on so small a body before.[5] The French space agency CNES leads operations for the two CubeSats.[5]

The impact Hera studies is described on the DART page, and its place in Earth's defenses in Planetary defense.

Milestones

  1. October 7, 2024
    Launch on Falcon 9
  2. March 12, 2025
    Mars flyby, with a look at the moon Deimos
  3. October 15, 2026
    First braking burn: final approach to Didymos begins
  4. November 2026 expected
    Arrival at the Didymos system
  5. January 2027 expected
    Releases the Juventas and Milani CubeSats
  6. June 2027 expected
    Juventas attempts a landing on Dimorphos
  7. September 2027 expected
    Scheduled end of mission

Dates marked expected are agency estimates.

All missions and what each does next

Sources

  1. [1]European Space Agency, Hera — esa.int, retrieved October 26, 2026
  2. [2]European Space Agency, Brake! Time for ESA's Hera asteroid mission to go slow — esa.int, retrieved October 26, 2026
  3. [3]European Space Agency, ESA's Hera targets early arrival at Didymos asteroids — esa.int, retrieved October 26, 2026
  4. [4]NASA, NASA Confirms DART Mission Impact Changed Asteroid's Motion in Space — nasa.gov, retrieved October 26, 2026
  5. [5]CNES, Hera — cnes.fr, retrieved October 26, 2026

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