You will no doubt recall that an epic trial run of a plan that may one day save Earth took place in September. Did it work?
NASA’s Double Asteroid Redirection Test (DART) launched on 24 November 2021, heading towards Dimorphos - a giant lump of rock hurtling through space.
Just under a year later, after travelling 6 million miles, NASA's $330 million spacecraft thumped into Dimorphos’s surface on 26 September at the mind-boggling speed of 14,000 miles per hour.
The collision wasn’t an accident but the mission’s goal: NASA was attempting to deflect the small asteroid’s orbit in a rehearsal for a future mission that could one day deflect an asteroid on a collision course with Earth, should one ever be found. After all, we can't rely on Hollywood action heroes every time.
Three minutes after impact, the Light Italian CubeSat for Imaging of Asteroids (LICIACube) - which had separated from DART fifteen days earlier - flew past to photograph the impressive dust cloud raised by the impact. So far, so good.
The goal was to shorten the orbit by 1 percent – about 10 minutes – though anything over 73 seconds would be a success. Happily, we can breathe a sigh of relief as the new orbit time has been recorded at a reduction of 32 minutes.
So, what next? The DART team now want to understand exactly how DART transferred its energy to Dimorphos. One particular area of interest is the dust cloud, as the recoil from its ejection could have amplified the impact. Therefore, launching in October 2024 and due to arrive in the system in 2026, the European Space Agency’s Hera spacecraft will observe Dimorphos for six months, mapping the surfaces and interior to fully understand the effect of the impact.
Should a hazardous asteroid ever be discovered, this understanding will help predict the path of a deflected space rock and keep our planet safe.