For the first time in history, a spacecraft is heading towards an asteroid whose orbit was deliberately changed by human beings.
The European Space Agency (Esa)’s Hera mission is now firmly on course to reach the Didymos binary asteroid system later this year, following a successful deep-space manoeuvre.
WHAT DID HERA JUST DO IN SPACE?
Hera completed the second of two deep-space manoeuvres on its long journey from Earth. The burn used 123 kg of hydrazine fuel and shifted the spacecraft’s velocity by 367 metres per second.
To put that in perspective, that is roughly the same as an object accelerating from a complete standstill to supersonic speed.
The manoeuvre was split across three engine burns, plus one smaller correction burn, carried out over roughly four weeks.
Its main purpose was to align Hera’s orbit around the Sun with that of the Didymos system. Esa’s Estrack network of deep-space antennas confirmed it went exactly as planned.
WHY IS THE DIDYMOS ASTEROID SYSTEM SO SPECIAL?
In 2022, NASA’s Dart spacecraft deliberately crashed into Dimorphos, the smaller moon of the asteroid Didymos, successfully nudging it into a slightly different orbit. It was a landmark test of humanity’s ability to defend Earth from a potential asteroid strike.
Hera’s job is to follow up. It will survey the crash site in detail, study the crater left behind, and help scientists understand exactly how effective the impact was. The goal is to turn asteroid deflection from a one-off experiment into a reliable, repeatable technique for protecting our planet.
HOW WILL HERA FIND THE ASTEROID?
Arriving at a small, dark asteroid is far trickier than reaching a planet. Hera will actively search for Didymos and Dimorphos, keeping them in its field of view during a three-week approach phase. Once close, it will deploy two CubeSats for detailed study.
Hera is expected to arrive at Didymos in late 2026.
