NASA’s DART planetary defense mission, en route to impacting an asteroid on September 26, has captured an image that encompasses the planet Jupiter and its four largest moons.
In its path, the spacecraft’s imager, the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) instrument, has taken thousands of star images. The images provide the Johns Hopkins Applied Physics Laboratory (APL) team leading NASA’s mission with the data needed to support the spacecraft’s ongoing tests and trials in preparation for launch. kinetic impact of the spacecraft on Dimorphos, the moon of Didymos.
DRACO will capture images of Didymos and Dimorphos; will also support the autonomous guidance system of the spaceship, autonomous navigation in real time small body maneuvering (SMART Nav), to guide DART to impact.
On July 1 and August 2, the mission operations team pointed the DRACO imager at Jupiter to test the SMART Nav system. The team used it to detect and target the moon Europa from Jupiter as it emerged behind Jupiter, similar to how Dimorphos will separate visually from the larger asteroid Didymos in the hours before impact.
Although the test obviously did not involve the DART collision with Jupiter or its moons, gave the SMART Jupiter and its major moons team, imaged by the APL-led DART Nav spacecraft, the opportunity to assess how well the SMART Nav system performs in flight. Prior to this Jupiter test, SMART Nav tests were performed using ground simulations.
The SMART Nav team gained valuable experience from the test, including how the SMART Nav team views spaceship data. “Every time we do one of these tests, we tweak the screens, make them a little better and a little more responsive to what we’ll actually be looking at during the actual terminal event,” Peter Ericksen, software engineer at SMART, said in a statement. nav in APL.
The DART spacecraft is designed to operate fully autonomously during terminal approach, but the SMART Nav team will monitor how objects are tracked in the scene, including their intensities, the number of pixels, and the consistency with which they are identified. Corrective action using pre-planned contingencies will only be taken if there are significant and mission-threatening deviations from expectations.
With Jupiter and its moons, the team had the opportunity to better understand how intensities can vary and the number of pixels of the objects as the targets move through the detector.
“The Jupiter probes gave us a chance for DRACO to get an image of something in our own solar system,” said Carolyn Ernst, DRACO instrument scientist at APL. “Pictures look fantastic and we’re excited for what DRACO will reveal about Didymos and Dimorphos in the hours and minutes leading up to impact!”
DRACO is a high-resolution camera inspired by the imager on NASA’s New Horizons spacecraft that returned the first close-up images of the Pluto system and the Kuiper Belt object Arrokoth.
DART is the world’s first planetary defense test mission, intentionally executing a kinetic impact on Dimorphos to slightly change its motion in space. While no known asteroids pose a threat to Earth, the DART mission will show that a spaceship can navigate autonomously to a kinetic impact on a relatively small target asteroid, and that this is a viable technique for deflecting a truly dangerous asteroid, if one is ever discovered.