By ELLEN BARRY
MOSCOW — Russia’s top space researchers will hold a closed-door meeting to plan a mission to deflect 99942 Apophis, an asteroid that will fly close to Earth two decades from now, said Anatoly N. Perminov, the head of Russia’s space agency, during an interview on Russian radio on Wednesday.
Mr. Perminov said Apophis, named for the Egyptian god of destruction, is about three times the size of the Tunguska meteorite, apparently the cause of a 1908 explosion in Siberia that knocked over an estimated 80 million trees. He said that according to his experts’ calculation, there was still time to design a spacecraft that could alter Apophis’s path before it made a dangerous swing toward Earth.
“I don’t remember exactly, but it seems to me it could hit the Earth by 2032,” he said, adding, “We’re talking about people’s lives here. It’s better to spend several million dollars and create this system, which would not allow a collision to happen, than wait for it to happen and kill hundreds of thousands of people.”
In fact, Apophis’s chances of hitting Earth have been downgraded since it was discovered in 2004, NASA said this year. Scientists originally thought the orbit of the 1,000-foot-long asteroid gave it a 2.7 percent chance of hitting Earth on its first approach in 2029, but after studying its path they said it would remain 18,300 miles above the planet’s surface.
On a second approach, in 2036, it was originally given a 1-in-45,000 chance of hitting Earth, but the odds were reduced to 1 in 250,000. The odds of impact on its third approach, in 2068, are 1 in 333,000, NASA scientists say.
Scientists have proposed various methods of averting an asteroid impact, among them a spacecraft that would land on the asteroid and, using electric motors, very gradually turn its trajectory. Another method would involve striking it with missiles or employing a satellite that used gravitational pull to change the orbit.
Mr. Perminov said the plan he envisioned would involve “no nuclear explosions; everything will be based on the laws of physics.” Once a mission has been developed, Russia will invite NASA, the China Space Agency and the European Space Agency to participate, he said.
Russell L. Schweickart, a former Apollo astronaut who is chairman of the B612 Foundation, a California group that promotes efforts to deflect asteroids, hailed much of the proposal and said Mr. Perminov was the most influential official ever to articulate a coordinated deflection plan. But he objected to using Apophis to test new deflection methods, saying there was more risk if something went wrong.
“It takes a very small change in the Apophis orbit to cause it to impact the Earth instead of missing it,” Mr. Schweickart said. “There are a million asteroids out there. Find another one.”