NASA launches spacecraft to hit an asteroid


The DART (Double Asteroid Redirection Test) space mission, initiated by NASA’s Planetary Defense Coordinating Office, was launched on Nov. 24, 2021. On Oct. 2, 2022, the DART spacecraft will seal itself into the surface of the near-Earth asteroid Dimorph, thereby changing its orbit.

SpaceX’s Falcon 9 rocket will be used to launch the DART spacecraft. It was launched from the U.S. Space Force Vandenberg Base in California at 9:20 Moscow time on Nov. 24. After entering orbit, DART will head toward the dual near-Earth asteroid system (65803) Didim and Dimorph. On its way there, it will pass near asteroid 2001 CB21 in late February 2022.

The pair of asteroids Didim and Dimorph is a perfect fit for a spacecraft impact test. The first asteroid is 780 m in diameter, Dimorph is slightly smaller and has a diameter of about 160 m. Their orbit lies in the same plane as the Earth, and this allows the brightness fluctuations of Didymph to accurately determine the orbital period of Dimorph. DART will impact almost in the center of the small asteroid at a velocity of 6.6 km/sec. At the moment of impact, the mass of the apparatus will be about 550 kg. Scientists predict that this should reduce the asteroid’s orbital period around Didim by several minutes. At the time of the collision, the binary system will be 11 million km away from us. Astronomers will make careful observations of the asteroids, and later collected data will be compared with a computer model to assess our ability to correctly calculate the consequences of impact on space bodies.

DART has a mass of 670 kg at launch, and its only instrument is a DRACO navigation and research camera. As can be guessed, in addition to taking pictures of the two asteroids, it will be responsible for navigating the spacecraft. The Applied Physics Laboratory at Johns Hopkins University has developed a new algorithm for real-time autonomous navigation for DART. In the final hours before impact, the spacecraft will navigate using DRACO camera images. It will also send pictures to Earth at one-second intervals.

The spacecraft is equipped with the NEXT-C ion engine developed by the Glenn Research Center and Aerojet. Glenn and Aerojet Rocketdyne. It also features a hydrazine engine for maneuvering and attitude control. To power it, the satellite is equipped with two flexible solar arrays unfolding like rolls. They are 8.6 m long each, and the total power generated by the batteries will be 6.6 kW.

The Italian Space Agency’s LICIACube 6U cube will be launched along with DART. It will separate from the main spacecraft about 10 days before the collision and will fly on a parallel course to film the demise of DART from the side.

In 2024, the European Space Agency plans to launch the Hera (“Hera”) mission, which will consist of two 6U cubsats. In 2026, four years after DART’s demise, Hera will arrive at the asteroids Didym/Dimorph. Its tasks include a thorough study of the crater left by DART and determination of the exact mass of Didym.

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