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NASA DART Impactor
DART is a simple, low-cost spacecraft. The main structure of the spacecraft is a box with dimensions of roughly 1.2 x 1.3 x 1.3 meters, from which other structures extend to result in measurements of roughly 1.8 meters in width, 1.9 meters in length, and 2.6 meters in height. The spacecraft has two very large solar arrays that when fully deployed are each 8.5 meters long. DART will navigate to crash itself into Didymos B at a speed of approximately 6.6 km/s.
Payload – DRACO
The DART payload consists of a single instrument – the Didymos Reconnaissance and Asteroid Camera for Op-nav (DRACO). DRACO is a high-resolution imager derived from the New Horizons LORRI camera to support navigation and targeting and to determine the impact site and geologic context.
DART will also carry a CubeSat contributed by Agenzia Spaziale Italiana (ASI), named LICIACube – Light Italian CubeSat for Imaging of Asteroids. The DART spacecraft will deploy LICIACube roughly two days prior to impact. LICIACube will capture images of the DART impact, the resulting ejecta cloud, and potentially a glimpse of the impact crater on the surface of Didymos B.
DART is a NASA-funded technology demonstration of a kinetic impactor technology that could be used to mitigate the threat of a hazardous asteroid. The DART project will demonstrate that a simple spacecraft can navigate itself to a successful impact on the target, and will measure the effect of that impact on the natural asteroid. The investigation will help NASA better prepare for asteroids that might one day pose a danger to the inhabitants of Earth and demonstrate other technologies, which have applications to future missions as well:
DART's first main challenge is to reliably target and squarely impact the small moonlet of Didymos, a 160-meter diameter target when it is 11 million kilometers away from Earth. The DART team has developed algorithms for autonomous optical guidance, navigation and control (GNC), called SMART Nav (Small-body Maneuvering Autonomous Real Time Navigation). The autonomous SMART Nav system will identify and distinguish between the two bodies at Didymos and then direct the spacecraft toward the smaller moon, Didymos B, all within roughly an hour of impact. To accurately navigate to the asteroid using onboard systems, the DART team is leveraging decades of missile guidance algorithms developed at APL.
NEXT-C ion engine during ground testing at NASA Glenn Research Center. (Credit: NASA GRC/Aerojet Rocketdyne/NEXT-C)
Advanced Ion Propulsion
DART will use NASA's NEXT–C (NASA's Evolutionary Xenon Thruster–Commercial), an ion propulsion system developed by NASA Glenn Research Center and Aerojet. Electric propulsion systems are powered by accelerating electrically charged atoms formed from the propellant, using electric and magnetic fields generated by solar power, and can achieve high speeds over long periods. NEXT–C offers fuel efficiency and operational flexibility that make it ideal for many classes of robotic missions.
The Roll Out Solar Array (ROSA) during deployment outside the International Space Station in 2017. (Credit: NASA/ JSC)
Roll Out Solar Arrays (ROSA)
Demonstrated on the International Space Station previously, ROSA provides a compact form and light mass for launch that then deploy into two large arrays once in space, each extending 8.6 meters in length.
Transformational Solar Array
Using ROSA as the structure, the array is equipped with very high efficiency solar cells and reflective concentrators, providing 3 times more power than current solar arrays.
Using Field Programmable Gate Arrays (FPGA) based electronics provides more flexibility for the spacecraft's navigation, image processing, and communications systems.
Radial Line Slot Array (RLSA)
This low-cost, high-gain antenna enables high efficiency communications in a compact form.