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DART, the Double Asteroid Redirection Test, is the first mission to test a potential method of deflecting an asteroid on course to hit Earth. Launching in 2021 and arriving at asteroid 65803 Didymos in 2022, it will intentionally crash into the asteroid's small moon, Dimorphos.

The crash should change Dimorphos' orbital period around Didymos by 4.2 minutes, a large enough change to measure from Earth-based telescopes. Such a change would show that if we spot a potentially hazardous asteroid in time, a DART-like impact could change its course enough to miss Earth.

DART is NASA's contribution to the Asteroid Impact and Deflection Assessment (AIDA) mission, a NASA-ESA collaboration. After DART’s impact, in 2025, ESA would send a follow-on spacecraft called Hera to Didymos to observe the crater DART created.

En route to Didymos, DART may fly past asteroid 2001 CB21. Shortly before DART strikes Dimorphos, it may also deploy an Italian Space Agency-built CubeSat to observe the impact.

DART Mission Updates
DART approaches the Didymos system


DART approaches the Didymos system

Mission Goals

DART's primary mission goals are:


Technology Goals

Sources: Cheng et. al (2018) | JHUAPL

Didymos System

Radar images of asteroid 65803 Didymos


Radar images of asteroid 65803 Didymos
Fourteen Arecibo radar images of the near-Earth asteroid (65803) Didymos and its moonlet, taken on 23, 24 and 26 November 2003. NASA’s planetary radar capabilities enable scientists to resolve shape, concavities, and possible large boulders on the surfaces of these small worlds. Photometric lightcurve data indicate that Didymos is a binary system, and radar imagery distinctly shows the secondary body.

65803 Didymos (Greek for "twin") is a binary, S-type near-Earth asteroid system. The system was discovered in 1996 by Spacewatch at Kitt Peak, Arizona, and confirmed as a binary asteroid in 2003.

Didymos' orbit


Didymos' orbit
Asteroid Didymos roughly travels between Earth's orbit and beyond Mars' orbit.

Didymos A (parent body)

Didymos B (Dimorphos)

Sources: NASA DART page | JPL Small-Body Database Browser | Asteroids have been hitting the Earth for billions of years. In 2022, we hit back.

Spacecraft overview

DART spacecraft


DART spacecraft
NASA's DART spacecraft.

Dimensions: Bus box 1.14 meters wide, 1.24 meters tall, 1.32 meters deep. DART's 2 roll-out solar arrays give the spacecraft a width of 12.5 meters when deployed.

Didymos arrival mass: 500 kg

Science instrument

DART has a single science instrument called DRACO (Didymos Reconnaissance & Asteroid Camera for OpNav), a dual-purpose telescope for observing the asteroid in high-resolution and for autonomous navigation. New Horizons LORRI heritage, built by JHUAPL. 208 mm aperture, f/12.6, 0.29-degree field of view. Panchromatic CMOS image sensor with 2560 x 2160 pixel resolution. Fletcher et. al (2018)

When DART is about 4 hours away from impact, its Small-body Maneuvering Autonomous Real-Time (SMART) navigation system will guide the spacecraft the rest of the way to Dimorphos. Using images from DRACO, SMART will differentiate between Didymos A and B and steer toward Didymos B.

Other technologies

NEXT-C (NASA Evolutionary Xenon Thruster – Commercial) solar electric propulsion system: DART's solar-electric propulsion system gives it launch window flexibility, since it will make multiple phasing loops around Earth before reaching escape velocity and heading on to Didymos. Dawn heritage, developed at NASA Glenn. Can be throttled from 25 to 235 mN, input power up to 7.4 kW. Fact sheet (2018)

Roll Out Solar Arrays (ROSA): DART's 2 large, roll-out solar arrays are necessary to provide power for the solar-electric propulsion system. The roll-out technology was successfully tested in space from the International Space Station in 2017. Beginning-of-life power: 6.6 kW. Manufacturer: Deployable Space Systems (DSS)

Past milestones


DART's planned budget is $313.9 million spread out over 8 years. This covers spacecraft development, launch vehicle, and operations through the end of its primary mission in late 2022.

Double Asteroid Redirection Test costs per fiscal year. Amounts after the current year are official projections. Source: Planetary Science Budget Dataset, compiled by Casey Dreier for The Planetary Society (accessible on Google Sheets or downloadable as an Excel file).

External resources

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