Before it embarks on its catastrophic voyage to collide with an asteroid’s moon, the National Aeronautics and Space Administration’s (NASA) DART mission has obtained unique photographs of our planet Earth. The DART project will take pictures of the mission and return them to Earth using an impactor spacecraft and a reconnaissance satellite created by the Italian Space Agency (Agenzia Spaziale Italiana).
The monitoring CubeSat sent back a rare photograph of Earth from a distance of almost 11 million kilometres as part of a practise run for tomorrow’s impact.
The DART mission and the CubeSat were launched on a SpaceX Falcon 9 rocket in late 2017; tomorrow’s event will provide NASA with a once-in-a-lifetime chance to test the system as the asteroid approaches Earth at its closest point for the foreseeable future. Together with the satellite, its impactor spacecraft was launched, and early this month, as the duo approached their destination, the imaging spacecraft parted ways with the impact vehicle.
Officially known as LICIACube, the imaging spacecraft has two optical cameras. These will take pictures of the asteroid’s surface and, more crucially, will record the impact of the impactor spacecraft with the moon of the asteroid system.
The parent asteroid Didymos and its moonlet asteroid Dimorphos are both included in the target asteroid system, which NASA refers to as the Didymos asteroid system.
The moonlet asteroid, according to estimations from the NASA, is estimated to weigh 5 billion kilos, while the impact spacecraft will weigh about 570 kilogrammes.
Prior to the impact event tomorrow, both of these cameras were tested, with one of them taking a picture of the Earth and the other a picture of the Pleiades star cluster.
By examining if the moonlet asteroid’s orbit around the main asteroid changed, NASA will decide whether the mission was successful or not. As there would be less space between Earth and the asteroid system, the agency will be able to see the asteroid more clearly through telescopes on Earth. This is one of the main reasons why late September has been picked as the date for impact.
The spacecraft will reach full autonomy four hours before landing while ground controllers can still manually steer it. It is difficult to manage the spaceship manually because of the delay in communication and the fact that it will be moving at 14,000 miles per hour when it collides.
When the spacecraft switches its orientation from Didymos to Dimorphus an hour before impact, the moonlet will only be visible as a single tiny pixel on the camera. An image received on the ground would be about 45 seconds late given the latency of each image, which is 2.5 seconds, the travel time of 38 seconds, and the processing time of up to 8 seconds.
The project will also enable NASA to examine the asteroid’s surface and understand how various surface types react to collision. Since they frequently seem fluid-like due to their low density, not all asteroids have solid surfaces.
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