Jan 9 2006
The U.S. is poised next week to fire an unmanned spacecraft toward Pluto at a speed of 10 miles per second, the highest velocity any space mission has ever been rocketed from Earth, Aviation Week & Space Technology reports in its January 9 issue.
But there are some risks to the planned January 17 launching of the $700 million "New Horizons" Pluto mission, says AW&ST. The spacecraft is headed so far from the Sun that it must obtain electricity from a radioisotope thermoelectric generator (RTG) powered by highly radioactive plutonium.
Although the plutonium is encased in a blast-resistant container, AW&ST reports that the U.S. Energy Department will have sixteen mobile emergency field teams and two radiological control centers positioned discretely around Cape Canaveral to ensure public safety in the event of a launch explosion.
Many such RTG systems have been launched on earlier spacecraft without incident. AW&ST reports one new factor will be the launch on a previously untested 2.4 million lb. thrust version of the Lockheed Martin Atlas V rocket carrying a Boeing Delta II upper stage.
In an exclusive report, AW&ST says that in addition to precautions at Cape Canaveral, the U.S. State Dept. is contacting Australia and several nations in southern Africa to ensure public safety as the probe passes near those countries during the latter phases of the launch. Reunion Island, a popular French vacation spot, also lies underneath the basic flight path, the magazine reports.
How fast is 10 miles per second? At that speed of 36,000 mph, the probe will pass the Moon in only 9 hours, and would be able to cross the entire U.S. in just 4 minutes.
The velocity is about 27 times faster than the Concorde supersonic transport and 10,000 mph faster than most previous spacecraft departing Earth for the Moon or planets. It will also be fast enough for New Horizons to pass by Jupiter within 13 months -- a several year trip for most previous spacecraft.
Jupiter's gravity will further accelerate New Horizons to 47,000 mph, fast enough for it to reach Pluto 3 billion miles from Earth as early as 2015, after a nearly ten year transit.
No previous space mission has ever studied up close the 1,470 mi. diameter Pluto and relatively nearby 50 mile wide Kuiper Belt objects. They are believed to be debris left over from formation of the solar system 4.5 billion years ago.
Other spacecraft like Pioneer 10 and 11 and Voyager 1 and 2, have flown further than Pluto but never ventured near it. They carried politically correct "greetings from Earth" on plaques and phonograph records. But not New Horizons.
The mission's lead manager Alan Stern from the Southwest Research Institute at Boulder, Colorado, told AW&ST that doing something like that involved too much federal bureaucracy.
Instead, the half-ton New Horizons spacecraft is carrying the names of more than 430,000 space enthusiasts and a piece of material from Burt Rutan's SpaceShipOne, the first privately built manned spacecraft. It is also carrying material commemorating Pluto's discoverer Clyde Tombaugh, who was cremated after his death in 1997 at age 90.
http://www.aviationnow.com