On November 24 at 06:21 UTC, Falcon 9 booster 1063 launched NASA’s Double Asteroid Redirection Test, or DART, from SLC-4E at Vandenberg Space Force Station in California. DART is SpaceX’s first proper interplanetary mission and the first interplanetary launch from SLC-4E. 

Booster 1063 landed on the droneship Of Course I Still Love You (OCISLY) stationed several hundred kilometers downrange. This was only OCISLY’s second catch since being moved from Florida earlier this year.

After two upper-stage burns, DART was released to begin its several-month cruise out to the asteroid Didymos, arriving in September 2022. It is only 610 kilograms, about the mass of a Holstein cow, and takes up barely more than a meter of space in Falcon 9’s payload fairing. This tiny mass allows Falcon 9 to launch it south from California and still reach the required escape vector for its interplanetary mission despite losing the benefit of launching east from Florida and getting a kick from the Earth’s rotation.

DART’s mission is to impact Didymos’ moon, Dimorphos, which is unofficially known as Didymoon. This will, if all goes as planned, demonstrate that humanity can use the kinetic impact method, by which we mean the “wack an asteroid with a spacecraft method” to change the orbit of an asteroid so that it doesn’t hit the Earth.

Why do we need to go all the way out to an asteroid millions of kilometers from Earth and hit it instead of just simulating it on a computer? The answer is because our understanding of the physics of impacts on regolith (loose rock) is very limited. The strange physics of interacting rock and ejected material makes it very hard to model an impact.

Didymos is at no risk of impacting the Earth in the future. Its moon was selected because its quick orbit allows easy measurement of the effects of the impact, and those changes can’t increase the risk of this two-rock system impacting the Earth. The total shift in the orbital period will be about ten minutes, at most.

Before impact, DART will release the ESA-provided CubeSat LICIACUBE. It has two cameras with the delightful backronyms LUKE (LICIACube Unit Key Explorer) and LEIA (LICIACube Explorer Imaging for Asteroid), which will observe the impact of DART, the plume produced, and potentially even the impact crater before LICIACUBE itself impacts Dimorphos.

DART has just one instrument – DRACO (Didymos Reconnaissance and Asteroid Camera for Optical navigation). Derived from the LORRI instrument on New Horizons, it combines the roles of separate cameras for navigation and science imaging into one instrument. Like many other telescopes, both on Earth and in space, DRACO uses a Ritchie-Chrétien optical assembly with a CMOS sensor like the one in many phones. This combo gives it a 0.3-degree field of view of its surroundings.

DART also hosts several technology demonstration experiments, including SMART-Nav, an autonomous navigation system. It will ensure that DART impacts Dimorphos. This new system, assures DART can perform its mission, particularly the critical last hours of the flight, without human intervention.

More Information

DART Launch Moves to Secondary Window (NASA)

PDF: DART press kit (JHUAPL)

SMART Nav: Giving Spacecraft the Power to Guide Themselves (NASA)

Launch video