Asteroid Impact Mission
The Asteroid Impact Mission (AIM) is a candidate mission currently undergoing preliminary design work (phase B1). The mission concept is being consolidated in view of a potential discussion at ESA’s Council of Ministers in December 2016 for approval. Assuming success, the mission concept will then become an actual ESA mission and work can begin at once on translating computer-aided design drawings into bent metal and cast composite.
ESA considers AIM to be a small mission of opportunity to demonstrate technologies mainly in the telecommunications domain, but as its Proba family of missions has demonstrated, the best way to prove new technologies is to achieve valuable scientific return.
Launched in October 2020, AIM would travel to a binary asteroid system – the paired Didymos asteroids, which will come a comparatively close 16 million km to Earth in 2022. The 800 m-diameter main body is orbited by a 170 m moon, informally called ‘Didymoon’.
This smaller body is AIM’s focus: the spacecraft would perform high-resolution visual, thermal and radar mapping of the moon to build detailed maps of its surface and interior structure.
The main AIM spacecraft is planned to carry at least three smaller spacecraft – the Mascot-2 asteroid lander, being provided by DLR (Mascot-1 is already flying on JAXA’s Hayabusa-2), as well as two or more CubeSats.
AIM is intended to qualify two way optical communications for deep space. It will map Didymoon, down to 1-m resolution, rapidly returning this copious volume of data to Earth in by laser link, to ESA’s Optical Ground Station in Tenerife.
AIM would also qualify an inter-satellite communication network in deep space, between AIM, the MASCOT-2 lander and the CubeSats.
As well as a high-resolution imager, AIM’s scientific payload is forecast to include a thermal infrared imager to study the surface geophysical and thermal properties of Didymoon, a high-frequency radar to sound the asteroid’s surface and shallow subsurface and a low-frequency radar to map its deep interior structure.
Assuming its adoption as an ESA mission, AIM would be launched on an Ariana 6.2 rocket from French Guiana in October 2020. Its one-month launch window is a firm deadline in order to reach Didymos approximately 18 months later.
If approved, AIM would also be Europe’s contribution to the larger Asteroid Impact & Deflection Assessment mission: AIDA. Around four months after AIM's arrival, the NASA-led part of AIDA will arrive: the Double Asteroid Redirection Test, or DART, probe will approach the binary system – then crash straight into the asteroid moon at about 6 km/s.
AIM is intended to be watching closely as DART hits Didymoon. In the aftermath, it will perform detailed before-and-after comparisons on the structure of the body itself, as well as its orbit, to characterise DART’s kinetic impact and its consequences.