World’s First Dedicated `Planetary Defense Mission` Against Asteroids
We now have the opportunity to honour another groundbreaking space mission, whose self-sacrificing death will add another significant notch to our space belt, following the birth and deployment of the magnificent James Webb Space Telescope earlier in the year. A NASA project that has been in the works for several years, the Double Asteroid Redirection Test, or DART mission, will allow us to determine our level of preparedness for potential extinction-level planetary threats. The National Aeronautics and Space Administration's (NASA) DART spacecraft successfully collided with an asteroid on Tuesday, setting a new record. The pioneering mission's goal was to determine whether asteroids that could one day endanger the Earth could be safely eliminated. NASA and Johns Hopkins teams have successfully tested the world’s first dedicated planetary defense mission against future asteroids headed our way.
Tuesday’s mission was called Double Asteroid Redirection Test, or DART. The asteroid Dimorphos that is being attacked is actually a satellite of Didymos, a slightly bigger asteroid. Dimorphos is around 160 m broad, compared to Didymos' maximum width of 780 m. This two-body system orbits the Sun while Dimorphos revolves around Didymos. Dimorphos' significantly shorter orbit around Didymos was one of the factors that led researchers to choose it as a target. If Didymos itself was targeted and an attempt was made to quantify the shift in its orbit around the Sun, the variation in its orbit would likely be less subtle and therefore more difficult to observe. In November of last year, the DART mission was inaugurated. The collision is likely to have created a crater on Dimorphos.
Hitting a distant object in space is not a novel achievement. It has been done earlier, and not just by NASA. The Anti-satellite tests, carried out by a few countries including India, have demonstrated several times the capability to strike, and destroy, fast-moving space assets with remarkable precision. Considering the vastness of space, the speed of the objects and the distances involved, these anti-satellite tests are probably more precise than attempting to hit a bullet with a bullet in mid-air. But setting up a planetary defence mechanism to deal with asteroid collisions is fundamentally different from anti-satellite strikes. Man-made space assets, almost all of them in near-Earth orbits, are extremely fragile and can easily be destroyed, or atleast rendered useless, by even minor impacts. The key is to manage the hit, and the objective is achieved.
We need to measure the impact's aftereffects now that we have successfully hit the Sardar Sarovar Dam-sized boulder with the 600 kg refrigerator-sized probe. Dimorphos' orbit around Didymos was intended to be shortened by the mission by 10 minutes, and NASA experts will examine this claim in the upcoming weeks. The Light Italian CubeSat for Imaging of Asteroids (LICIACube), which the spacecraft launched 15 days prior to the impact, was also on board DART in order to measure this. The effectiveness of the mission will be evaluated by the LICIACube in cooperation with a large number of observatories in space and on the ground as they track the asteroid debris and its new flight path. In around four years, the European Space Agency (ESA) will investigate both space rocks and the impact crater to see how much we could influence the body.
Even though the Dart's image stream abruptly ceased at impact, a tiny Italian cubesat was still following three minutes later. At a distance of 50 miles, it was safely taking pictures. Data from the LiciaCube will be sent back to Earth during the next few days. However, it was clear from the first photo that the cubesat had seen the plume of debris that Dart had dredged up. The European Space Agency (ESA) will station the three Hera project spacecraft in Didymos and Dimorphos in four years to carry out more research. However, it will take a few more years before any significant changes in the trajectory will become obvious, so we won't know the concept's ultimate success until then.
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