Spacecraft DART is currently heading for its fatal final destination: Dimorphos. And along the way, he has already shot some important space photos.
Although the chances are pretty slim that – just like in the new Netflix movie ‘Don’t look up’ – a comet is on a collision course with Earth, NASA leaves nothing to chance. In order to protect the Earth from future near-Earth objects, the US space agency announced about a month ago the Double Asteroid Redirection Test (DART) mission launched. Spacecraft DART is currently heading for an asteroid and will ram it to alter its orbit. And along the way, DART has already shot some important space photos.
DART mission
Spacecraft DART is en route to asteroid Didymos. Didymos (Greek for twins) is a binary system that consists of two parts. Didymos A has a diameter of 780 meters. Around Didymos A, a smaller celestial body of about 160 meters orbits. And this ‘moon’ – called Dimorphos – will play the main role during the mission.
Goal
The intention is for the DART spacecraft to deliberately smash itself against the small moon. And at about 6 km/sec (about nine times faster than a bullet). With this, the researchers hope to change Dimorphos’ orbit. Because by gently tapping the space rock, if everything goes according to plan, a small change in the orbital speed is forced.
Illustration of the mission. DART will ram the moon Dimorphos. Next, observations from Earth will be used to measure the change in the moon’s orbit around the parent body. Image: NASA/Johns Hopkins Applied Physics Lab
Currently, Dimorphos completes one orbit around Didymos A every 11 hours and 55 minutes. Using the DART impact, the researchers only hope to slightly alter the moon’s orbit. Since Dimorphos is part of a binary system, it is then relatively easy to calculate the modified trajectory after DART hits it. The researchers suspect that its orbital time can be shortened by ten minutes. This would mean that a loop around Didymos A would take about 11 hours and 45 minutes after the collision.
We can also reassure you: Didymos currently poses no threat to Earth. The mission is therefore only a demonstration mission to see whether such a technique, in which the direction of a space rock is deflected by means of an impact, works. Although we may not want to think too much about it, it could just be that in the future a space rock will be on a collision course with Earth. And then of course we need to know how to deal with such dangerous near-Earth objects that could potentially damage our planet.
After the launch of DART, the mission team held its breath for a moment. Because would the spacecraft have survived the extreme vibrations of the launch and the temperature shift to -80 degrees Celsius in space? Because the parts of the telescopic instrument onboard DART are very sensitive to motion, even a small change in something in the instrument can have serious consequences.
Everything good
Fortunately, it soon became apparent that DART survived its launch unscathed. To everyone’s delight, he sent a photo of his view to Earth.
This is what DART saw when he first opened his single ‘eye’. Image: NASA/Johns Hopkins APL
The snapshot shows about a dozen stars that stand out brightly against the jet-black background. The stars are located near where the constellations Perseus, Aries, and Taurus intersect.
DART is a very simple spacecraft. There is therefore only one instrument on board, namely the DRACO instrument (short for Didymos Reconnaissance and Asteroid Camera for Op-nav). This instrument is an imaging camera derived from the Long Range Reconnaissance Imager on NASA’s New Horizons spacecraft. DRACO will visualize both parts of the Didymos system (so both the asteroid and its moon). In addition, this also includes the autonomous navigation system.
The mission team then used the photographed stars to determine very precisely how DRACO (see box) is oriented. It provided the first measurements of how the camera is positioned relative to the spacecraft. With those measurements in hand, the team could then make course corrections and target DRACO at more interesting objects, such as the star cluster Messier 38.
Photo of the open star cluster Messier 38, manufactured by DART. M38 is about 4,200 light-years away from Earth. Image: NASA/Johns Hopkins APL
Such images are very important to the mission. Because these photos help the researchers to reveal optical imperfections in the images and to determine exactly how bright an object is. And those are very important details that will lead to accurate measurements when DRACO will shoot pictures of its final destination.
All in all, it promises to be a groundbreaking mission, where a space probe will attempt to change the orbit of an asteroid for the first time. We still have to be patient though. Didymos is expected to pass through Earth next fall. And researchers have devised it in such a way that DART will ram the moon Dimorphos at exactly that moment. DART is expected to reach its target on September 26, 2022. And then we’ll see if its fatal impact is indeed an effective way to avert future nearers and save the Earth.
Source material:
“With Its Single “Eye,” NASA’s DART Returns First Images from Space” – NASA
Image at the top of this article: NASA/Johns Hopkins Applied Physics Lab