The Planetary Society conducted a competition in cooperation with European Space Agency (ESA) to design a mission to rendezvous with and “tag” the near-Earth asteroid 99942 Apophis.

The competition was also conducted in cooperation with NASA, the Association of Space Explorers (ASE), the American Institute of Aeronautics and Astronautics (AIAA), and the Universities Space Research Association (USRA). The purpose of the competition was to gather together a diverse and large collection of entries that could potentially used as a creative and useful starting point for a potential space agency project to tag any asteroid that may be coming dangerously close to Earth.

Apophis is a near Earth object (NEO) which in 2029 will come closer to Earth than the geostationary satellite orbit, and will be gravitationally perturbed to an unknown orbit, one that could hit Earth in 2036. Very precise tracking may be required to adequately determine the probability of a 2036 impact, and it may turn out that such precise tracking will require “tagging” the asteroid with a beacon, transponder or reflector of some kind.

It is possible that radar observations and tracking in the next few years will obviate the need for a tagging mission or concern about this particular asteroid: possible, but not certain. But, even in this case, the Apophis Mission Design Competition will be useful in advancing knowledge and capability for future missions to any asteroid that may threaten an impact with Earth. Apophis is treated as an example for mission design.

Competition Design Scenario

If the asteroid Apophis goes through a several-hundred-meter-wide “keyhole” in 2029, it will impact Earth in 2036. Imagine that over the coming years, more Earth-based observations of Apophis are made; however, we still find that the observations are not sufficient to know whether Apophis will or will not pass through the 2029 keyhole. A better orbit determination is needed so we know whether a deflection mission is required to prevent passage through the keyhole. This can be accomplished using a mission to emplace a device on or near the asteroid that enables precise tracking of Apophis. This mission was the focus of the design competition.