Plate Nº 63 · recorded October 9, 2026
Space & AstronomyReported finding
Hera spacecraft will fire 3 thrusters for 93 minutes to brake toward asteroid
ESA's Hera spacecraft will fire three thrusters for 93 minutes on October 15, 2026, to slow itself by a few hundred meters per second ahead of its November arrival at Dimorphos, the asteroid NASA hit with DART in 2022.
By Nathan Brooks3 min read611 words
In brief
- Hera will fire 3 hydrazine thrusters continuously for 93 minutes on October 15, 2026, reducing its velocity by a few hundred meters per second.
- Arrival at the Didymos-Dimorphos system is expected in November 2026, with 6 months of investigation planned.
- Hera launched October 7, 2024, as a follow-up to NASA's DART impact on Dimorphos in 2022.
- Hera will deploy two CubeSats, Milani (spectral mapping) and Juventas (radar soundings), at the asteroid.
- Didymos is about 800 meters wide; Dimorphos is about 170 meters in diameter, roughly the size of Rome's Colosseum.
Hera fires its thrusters for 93 minutes to slow down
ESA's Hera spacecraft will fire three thrusters continuously for 93 minutes on Thursday, October 15, 2026, reducing its speed by a few hundred meters per second as it approaches the asteroid Didymos and its small moon Dimorphos. The braking maneuver is the final step before a November rendezvous with the same asteroid NASA smacked with the DART spacecraft in 2022.
In a statement, ESA described the technical sequence: "Hera will rotate around so that its ring of Orbit Control Thrusters face toward the Didymos system. Three of these hydrazine-based thrusters will be ignited at once, burning continuously for a total of 93 minutes, to reduce Hera's velocity relative to the asteroids by a few hundred meters per second."
The spacecraft launched on October 7, 2024, and has already completed a deep-space course correction in 2026 and a software upgrade in July 2026.
What does Hera actually plan to do at Dimorphos?
Once Hera reaches the asteroid pair, it will spend six months investigating the aftermath of the DART impact. The mission marks the first dedicated study of a binary asteroid system. ESA frames the work as a "crime scene investigation" of a deliberate, human-made crater.
Two small companion spacecraft, called CubeSats, will ride along and deploy at the asteroids:
- Milani will perform spectral surface observations, splitting light reflected off Dimorphos into its component colors to map its composition.
- Juventas will take the first radar soundings ever attempted inside an asteroid, probing its internal structure.
Why does a 2022 asteroid collision still matter?
When DART struck Dimorphos on September 26, 2022, the impact measurably shifted the moonlet's orbit around Didymos. The collision proved that a spacecraft could deflect a small body, a key test of planetary defense. But key questions remain about what the impact actually did to the asteroid itself.
What three mysteries will Hera try to solve?
ESA has outlined three primary science goals for the mission:
- Is Dimorphos a rubble pile or a solid rock? Hera will measure the moonlet's density and composition in detail to determine whether it is loosely held together by gravity or a solid core covered in boulders.
- What does the DART crater look like? Hera will map the impact site at 10-centimeter (4-inch) resolution. Scientists have not ruled out the possibility that no traditional crater exists, and that the impact instead reshaped the entire asteroid.
- Where did the binary system come from? About 15% of known asteroids are binary systems, and their origins are unclear. Hera will compare the material of Didymos and Dimorphos to test whether the smaller body formed from material flung off a rapidly spinning Didymos.
How big are these asteroids?
For a sense of scale, Didymos measures roughly 800 meters (about half a mile) across, similar in size to the Golden Gate Bridge. Dimorphos, the smaller target of DART, is just 170 meters (about 560 feet) in diameter, roughly the size of the Great Pyramid of Giza or Rome's Colosseum.
What comes next?
If the October 15 burn succeeds, Hera will reach the Didymos system next month. Its instruments and two CubeSats will then begin the first close-up survey of a binary asteroid and the first forensic examination of a deliberately cratered world, data that scientists plan to fold directly into models of how Earth might one day push a threatening asteroid off course.
ESA project scientist Michael Küppers has framed the mission's stakes in the simplest terms: the more precisely researchers understand how DART changed Dimorphos, the better prepared humanity will be for a real asteroid threat.
via esa.int (Original)
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