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SPACE SCIENCES

First mission to defend planet Earth

ASA’s Double Asteroid Redirection Test (DART), the world’s first full-scale mission commercial ion engine, one of several
to test technology for defending Earth against potential asteroid or comet hazards, technologies being tested on DART for
Nwas launched on 24 November on a SpaceX Falcon 9 rocket from Space Launch future application on space missions.
Complex 4 East at Vandenberg Space Force Base in California. “At its core, DART is a mission of
Just one part of NASA’s larger planetary defence strategy, DART – built and managed preparedness, and it is also a mission of
by the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland – will impact unity,” said Thomas Zurbuchen, associate
a known asteroid that is not a threat to Earth. Its goal is to slightly change the asteroid’s administrator for the Science Mission
motion in a way that can be accurately measured using ground-based telescopes. Directorate at NASA headquarters
DART will show that a spacecraft can autonomously navigate to a target asteroid and in Washington. “This international
intentionally collide with it – a method of deflection called kinetic impact. The test will collaboration involves DART, ASI’s
provide important data to help better prepare for an asteroid that might pose an impact LICIACube, and ESA’s Hera investigations
hazard to Earth, should one ever be discovered. LICIACube, a CubeSat riding with DART and science teams, which will follow up
and provided by the Italian Space Agency (ASI), will be released prior to DART’s impact to on this ground-breaking space mission.”
capture images of the impact and the resulting cloud of ejected matter. Roughly four years DART’s one-way trip is to the
after DART’s impact, ESA’s (European Space Agency) Hera project will conduct detailed Didymos asteroid system, which
surveys of both asteroids, with particular focus on the crater left by DART’s collision and a comprises a pair of asteroids. DART’s
precise determination of Dimorphos’ mass. target is the moonlet, Dimorphos,
“DART is turning science fiction into science fact and is a testament to NASA’s which is approximately 160 metres
proactivity and innovation for the benefit of all,” said NASA administrator Bill Nelson. in diameter. The moonlet orbits
“In addition to all the ways NASA studies our universe and our home planet, we’re also Didymos, which is approximately 780
working to protect that home, and this test will help prove one viable way to protect metres in diameter.
our planet from a hazardous asteroid, should one ever be discovered that is headed Since Dimorphos orbits Didymos at
towards Earth.” a much slower relative speed than the
After DART separated from the second stage of the rocket mission, operators pair orbits the Sun, the result of DART’s
received the first spacecraft telemetry data and started the process of orienting the kinetic impact within the binary system
spacecraft to a safe position for deploying its solar arrays. About two hours later, the can be measured much more easily than
spacecraft completed the successful unfurling of its two, 28-foot-long, roll-out solar a change in the orbit of a single asteroid
arrays. They will power both the spacecraft and NASA’s Evolutionary Xenon Thruster – around the Sun.

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