Cape Canaveral - Nasa has a job for its new Orion spaceship even before launching it to Mars. The proposed mission would send it to an asteroid to study its composition. If it takes place as planned, it would be Orion's second mission with astronauts and precede the Mars mission by several years.
One of the tasks Nasa has laid out for its Orion spaceship long before the proposed trip to Mars is a rendezvous with an asteroid on the far side of the moon.
Nasa's timeline calls for the asteroid mission to take place in the mid-2020s as the third exploratory mission of the Orion spaceship that was set to make its debut test flight on Thursday.
The “foundation” for the flight that Nasa calls the asteroid redirect mission (ARM) was the European Space Agency (ESA) comet landing in November, said Steve Stich, one of the Nasa scientists managing the proposed asteroid mission.
“The demands of that mission laid down a heritage for us,” said Stich. “Without the work that the ESA did, the ARM wouldn't be possible.”
The ESA notched a first in space exploration with the November 12 landing on comet 67P/Churyumov-Gerasimenko. Stich said it was a “terrific” achievement even thought communications with the Philae probe were lost after the solar-powered batteries ran out.
Stich said scientists want to study asteroids because they are like “rubble piles” pieced together by gravity. Knowing what they are made of gives scientists more data about the universe and answers whether asteroids might hold resources that could be used in future space travel.
Nasa also says its ARM will “greatly advance” its path to landing humans on Mars by testing the capabilities Orion needs for a mission with astronauts to the Red Planet in the 2030s.
Scott Pace, an outside expert and director of the Space Policy Institute at George Washington University in Washington, DC, said the asteroid redirect programme is feasible and offers interesting engineering test opportunities.
“But it does not by itself represent a long-term programme of human space exploration,” he said in an email to dpa.
Pace is also dubious about other Nasa plans involving Orion, including a mission planned for 2021 that would include a crew - a goal that Orion programme manager Mark Geyer said remains firm.
Pace said it would be “possible to imagine a human mission to the vicinity of Mars in 2021” - in part due to a unique alignment of the planets at that time. He said there's probably too little time to take advantage of this opportunity.
But Nasa officials say while the goal is to fly the first Orion flight with a crew in 2021, they are not planning to send it as far as Mars.
There are a number of milestones Nasa must pass on the way to both the Mars and the asteroid missions. First among them is the completion of a much bigger rocket called the Space Launch System.
Nasa says the rocket, which it plans to use on the next Orion test flight two to three years from now, will be the “biggest, most capable rocket ever built.” It will have a lift capacity of 77 tons, which Nasa says is more than double that of any current rocket in service.
Another important milestone will be passed when Nasa decides the method it plans to use to “catch” the asteroid and “redirect” it to a distant retrograde orbit located beyond the moon where it can be visited by Orion and crew.
Both of the proposed methods would require sending an unmanned probe into space several years ahead of the Orion exploration mission. One method would capture the space rock in an inflatable device and the other would use a robotic arm to pluck off a boulder from the surface of an asteroid.
Which ever method is selected, the asteroid or asteroid mass would then be gradually positioned in the orbit and await the astronauts aboard Orion. Stich envisions just two, although the Orion is designed to carry up to six. They would spend 28 days on the mission, which would require several spacewalks.
He wouldn't say which of the two “redirect” methods he thinks is best, but said the method that would “bag” the asteroid in the inflatable device is something never done before, and the robotic arm method is 100 million dollars more expensive.
Stich said Nasa would announce which method it plans to use at a news conference on December 16.
Out of more than 1 000 asteroids observed, Nasa has located three candidates that could be targeted by the bag method and three that could be grabbed by the robotic arm.
Stich added that one of the side benefits of the proposed mission and its focus on asteroids is that it has helped Nasa fulfill a requirement that it notify Congress if it discovers an asteroid that poses a threat to Earth.
So far it hasn't found any that do, but it will continue looking while simultaneously plotting its mission. - Sapa-dpa