Asteroid-tracking proposal wins $25,000 prize

Published 28 February 2008

Depending on the direction it takes as it nears Earth in 2029, the asteroid Apophis may hit Earth in 2036, with what scientists fear would be an impact similar to that which caused the extinction of dinosaurs sixty-two million years ago; scientific and engineering organizations compete for funding of proposals on how to deal with the threat

A few days ago we wrote that planetary — and interplanetary — security are an integral part of homelands security. We wrote this in reference to the proposal by nine Israeli science students who designed a space vehicle for the specific purpose of tracking Earth-threatening asteroids — and destroying these asteroids if necessary. We are glad to see that others notice, too: The New Scientist’s David Shiga writes that a design for a low-cost spacecraft to rendezvous with and track the potentially Earth-threatening asteroid Apophis has won a $25,000 prize from a nonprofit space advocacy organization. The group hopes the prize will spur the world’s space agencies to plan missions to protect the planet from potentially dangerous impacts. The 250-meter asteroid Apophis will pass near Earth in 2029. If it passes through a “keyhole” in space a few hundred meters wide, then its trajectory will be altered in just the right way for it to hit Earth seven years later in 2036. The chance of this happening is small — just 1 in 45,000 — but if it were to hit Earth, Apophis is big enough to cause serious damage.

Now, the Pasadena, California-based nonprofit Planetary Society has announced the winner of a competition to design a mission to track Apophis and determine whether it poses a threat to Earth. The Planetary Society received 37 mission proposals from 20 countries. The winner was a proposal by SpaceWorks Engineering, of Atlanta, Georgia. Dubbed “Foresight,” the mission would put a small spacecraft in orbit around Apophis, where it would send pictures and data about the asteroid back to Earth. Its designers say that if they received funding, they could launch the mission as early as 2012 and arrive at the asteroid in 2013. The probe would determine the space rock’s trajectory in two ways. First, it would monitor its own position relative to the asteroid by bouncing laser pulses off the asteroid’s surface. It would also send radio signals to Earth that would allow its position relative to Earth to be tracked precisely. SpaceWorks says a few months of tracking would allow the asteroid’s 2029 flyby trajectory to be calculated with an uncertainty of less than 7 kilometres. The contest rules called for a mission that could reduce the uncertainty to 14 kilometers or lower, which is small enough to determine whether there is a significant chance of a 2036 impact without intervention.

At just $137 million, the mission’s projected cost would include $94 million to build the spacecraft, $21 million for operations, and $22 million for launch on a Minotaur IV rocket purchased from Dulles, Virginia Orbital Sciences Corporation. The spacecraft would weigh a mere 220 kilograms, and with its solar panels extended would be just 2.4 meters long.

We are very happy that this competition inspired innovative designs to solve an important problem that could affect life on Earth — as the dinosaurs learned the hard way,” says Bruce Betts, director of projects at the Planetary Society. “We hope the winning entries will catalyze the world’s space agencies to move ahead with designs and missions to protect Earth from potentially dangerous asteroids and comets.” Prize money was also awarded for proposals from two other teams, both of which would use radio tracking of a spacecraft in orbit around the asteroid to better determine the asteroid’s trajectory. The second-place prize of $10,000 was awarded to a team led by Juan Cano of the engineering firm Deimos Space of Madrid, Spain. That mission would cost $387 million, and would include more instruments than Foresight, including a radiometer that would measure heat radiation from the asteroid, which can subtly influence its trajectory. A third-place prize of $5,000 went for a proposal called APEX (Apophis Explorer), submitted by a team led by Paolo D’Arrigo of the aerospace firm EADS Astrium in the United Kingdom. The $494 million mission is even more complex, and would include six scientific instruments, including two devices for measuring the asteroid’s light spectrum. A further $10,000 was awarded for top student-led proposals.

The contest entries were judged by a panel of NASA and European Space Agency (ESA) experts.

NASA has previously said it would not consider mounting a deflection mission until the risk posed by Apophis was better understood. ESA is developing a mission called Don Quijote, which will hit another asteroid with a spacecraft to see if the impact changes the asteroid’s trajectory. There are several other other ideas for deflecting asteroids, such as pulling them off course with a “gravity tractor” and using mirrors to focus sunlight on — and thus partially vaporize — their surfaces, creating a thrust in the opposite direction.