On September 26, the Double Asteroid Redirect Test (DART) spacecraft will strike an asteroid and the spacecraft’s imager — the Didymos Reconnaissance and Asteroid Camera for Optical navigation, or DRACO — has snapped thousands of pictures of stars.
“Taking the scenic route. As our #DARTMission cruises towards its intentional impact with Dimorphos, an asteroid moonlet which poses no threat to Earth, the spacecraft’s imager has captured a picture of Jupiter and its four largest moons," NASA tweeted.
The team used SMART Nav system to detect and target Jupiter’s moon Europa as it emerged from behind Jupiter, similar to how Dimorphos will visually separate from the larger asteroid Didymos in the hours leading up to impact, as per NASA reports.
While the test obviously didn’t involve DART colliding with Jupiter or its moons, it did give the APL-led SMART Nav team the chance to assess how well the SMART Nav system performs in flight. Before this Jupiter test, SMART Nav testing was done via simulations on the ground.
According to a NASA release, the DART spacecraft is designed to operate fully autonomously during the terminal approach, but the SMART Nav team will be monitoring how objects are tracked in the scene, including their intensities, number of pixels, and how consistently they’re being identified.
Corrective action using preplanned contingencies will only be taken if there are significant and mission-threatening deviations from expectations. With Jupiter and its moons, the team had a chance to better understand how the intensities and number of pixels of objects might vary as the targets move across the detector.
The image taken when DART was approximately 16 million miles (26 million km) from Earth with Jupiter approximately 435 million miles (700 million km) away from the spacecraft—is a cropped composite of a DRACO image centered on Jupiter taken during one of these SMART Nav tests.
Two brightness and contrast stretches, made to optimize Jupiter and its moons, respectively, were combined to form this view. From left to right are Ganymede, Jupiter, Europa, Io, and Callisto.
In an official statement, Carolyn Ernst, DRACO instrument scientist at APL said, “The Jupiter tests gave us the opportunity for DRACO to image something in our own solar system. The images look fantastic, and we are excited for what DRACO will reveal about Didymos and Dimorphos in the hours and minutes leading up to impact!"
The Space Agency further said that the DART mission will demonstrate that a spacecraft can autonomously navigate to a kinetic impact on a relatively small target asteroid, and that this is a viable technique to deflect a genuinely dangerous asteroid, if one were ever discovered.
DART will reach its target on September 26, 2022.
