// block 755854 · space · 26 September 2022

DART hits an asteroid

The moment this block marks: DART's impact on Dimorphos, as announced by mission control at APL, 19:14 local time, 26 September 2022, 23:14:00 UTC. The first block mined after it is block 755,854, 26 September 2022, 23:22:56 UTC.

In November 2021, NASA launched a spacecraft with a single purpose: to fly into an asteroid. Its target, Dimorphos, is a moonlet 160 metres wide that orbits a larger asteroid, Didymos, 780 metres wide; neither poses any danger to Earth. The Double Asteroid Redirection Test, DART, was built and run for NASA by the Johns Hopkins Applied Physics Laboratory in Maryland, to find out whether striking an asteroid could change its path.

On 26 September 2022, after ten months in space, DART steered itself through its final approach, its only camera sending back ever closer views of a surface nobody had seen before. It struck Dimorphos at about 6.6 kilometres per second, some 11 million kilometres from Earth. Mission control at APL announced the impact at 19:14 EDT. Signals took about 38 seconds to cross that distance, so the spacecraft no longer existed when its last image arrived.

Telescopes around the world then timed the orbit of Dimorphos around Didymos. The impact had shortened it by many minutes, far beyond the 73 seconds the mission needed to count as a success: for the first time, people had deliberately changed the motion of a body in the solar system.

The first block mined after the impact, block 755,854, came about nine minutes later, at 23:22:56 UTC, with Dimorphos already moving on its new orbit. Its hash, like every hash, can be checked on any node.

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Sources

• NASA, NASA's DART Mission Hits Asteroid in First-Ever Planetary Defense Test: “Mission control at the Johns Hopkins Applied Physics Laboratory […] announced the successful impact at 7:14 p.m. EDT”
• Johns Hopkins APL, DART, The mission: “DART Impact: September 26, 2022, 7:14 p.m. EDT (23:14:24.183 UTC)”
• The Planetary Society, What DART has taught us so far: signals “took 38 seconds to reach Earth”