It might not look like much, but here is the first monumental image from the Double Asteroid Redirection Test (DART). Earlier this month, a circular door covering the aperture of its DRACO telescopic camera was opened, allowing the camera to take its first image.
Now, imagine what the camera’s last image will be like: a REALLY closeup view of a binary asteroid system, Didymos and especially, its moonlet Dimorphos.
The goal of DART is to intentionally collide with Dimorphos. If everything goes according to plan, this will alter the asteroid’s motion so that ground-based telescopes can accurately measure any changes.
DART is the world’s first planetary defense test mission. It will demonstrate that a spacecraft can autonomously navigate to and perform a kinetic impact on a relatively small target asteroid. This will test if this is a viable technique to deflect a genuinely dangerous asteroid.
DART will reach its target on September 26, 2022. FYI, the Didymos asteroid system does not pose a threat to Earth.
DART launched on November 24. As in any mission that launches to space, there’s always concern about how the instruments will react to the violent vibrations of launch and the extreme temperature shift. NASA said that because components of DART’s telescopic instrument are sensitive to movements as small as 5 millionths of a meter, even a tiny shift of something in the instrument could be very serious.
But all seems to be well with the DRACO camera. Below is another image taken on December 10.
DRACO (short for Didymos Reconnaissance and Asteroid Camera for Optical navigation) is a high-resolution camera, inspired by the imager on the New Horizons spacecraft. Recall the excitement of the first close-up images of the Pluto system, and later when New Horizons flew past the Kuiper Belt object, Arrokoth.
As DART’s only instrument, DRACO will capture images of the asteroid Didymos and its moonlet asteroid Dimorphos, as well as support the spacecraft’s autonomous guidance system to direct DART to its final kinetic impact.
DRACO’s first image, taken on Tuesday, December 7, 2021 was taken about 2 million miles (11 light seconds) from Earth – very close, astronomically speaking. The image shows about a dozen stars, crystal-clear and sharp against the black backdrop of space, near where the constellations Perseus, Aries and Taurus intersect.
NASA said the DART navigation team at the Jet Propulsion Laboratory used the stars in the image to determine precisely how DRACO was oriented, providing the first measurements of how the camera is pointed relative to the spacecraft. With those measurements in hand, the DART team could accurately move the spacecraft to point DRACO at objects of interest, such as Messier 38 (M38), also known as the Starfish Cluster, that DART captured in the second image, taken on December 10.
Located in the constellation Auriga, the cluster of stars lies some 4,200 light years from Earth. Intentionally capturing images with many stars like M38 helps the team characterize optical imperfections in the images as well as calibrate how absolutely bright an object is – all important details for accurate measurements when the spacecraft gets closer to Didymos and DRACO starts imaging the spacecraft’s final destination.