麻豆传媒

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NASA has a problem. It doesn鈥檛 have the money to complete its current human space-flight plan, which is meant to return people to the moon by 2020. And the Ares I rocket it is building to replace the space shuttle is not likely to be ready until 2017, although the International Space Station it is supposed to service is due to be tossed into the Pacific Ocean in 2016.

The White House tasked the Augustine committee with charting ways out of the mess. It responded last week with a menu of five plans, ranging from staying stuck in low Earth orbit to embarking on an ambitious series of missions to visit asteroids and orbit Mars. The options also differ in how long NASA would support the space station, how astronauts will get up to orbit, and the dollars required.

The committee evaluated each plan in 12 categories, such as benefits to science, safety and workforce retention. It assigned scores from -2 to 2 but did not offer overall scores. 麻豆传媒 has done so, however, by adding up the scores for each option. We have treated each category as equally important 鈥� an attitude President Barack Obama may not share. Here are the results 鈥� and the main pros and cons.

The status quo

If NASA continues on its existing path with no extra money, its new Ares I rocket and Orion crew capsule will not be ready until after 2016, by which time the International Space Station is scheduled to have been de-orbited. A return to the moon would not happen until 鈥渨ell into the 2030s, if ever鈥�, says the committee.

FOR: safety (0) 鈥� astronauts do not venture beyond Earth orbit

AGAINST: schedule (-2) 鈥� lack of funds postpones moon return indefinitely

OVERALL SCORE: -15

An iss extension and a cash-strapped moon programme

The Ares I rocket 鈥� which was set to make its first test flight this week 鈥� is cancelled and NASA sends astronauts to the ISS aboard commercial vehicles such as SpaceX鈥檚 Dragon capsule. A new plan to return to the moon may run out of money.

FOR: international cooperation (0) 鈥� ISS extension to 2020 pleases partners

AGAINST: schedule (-2) 鈥� human moon landings still wanted, but lack of funds may postpone them indefinitely

OVERALL SCORE: -5

The status quo, but with extra money

With $3 billion a year extra in its budget, NASA could return astronauts to the moon, but only by sacrificing the ISS after 2015.

FOR: schedule (0) 鈥� human moon landings by mid-2020s

AGAINST: international cooperation (-2) 鈥� ISS pull-out dismays partners

OVERALL SCORE: -3

Return to the moon, no further for now

This option also requires an extra $3 billion a year. One version of it would delay retiring the space shuttle to 2015 and reuse its technology for trips to the moon. The other would get there with a variant of the planned Ares V heavy-lift rocket. Commercial vehicles would fly to the ISS, which would be extended to 2020.

FOR: US skills retention (0) 鈥� if shuttle retirement is delayed

AGAINST: public engagement (0) 鈥� returning to moon arguably less exciting than other destinations

OVERALL SCORE: 4 or 5, depending on variant

Forays into deep space

In the 鈥渇lexible path鈥� option, astronauts would visit an asteroid, orbit Mars and land on the moon. Crews may also go to Lagrange points 鈥� places where the gravity of the sun and Earth, for instance, cancels out 鈥� to service telescopes and test Mars mission technology. Three versions differ only in the launcher used to get past low Earth orbit 鈥� all require $3 billion extra a year, and private rockets would fly to the ISS, kept aloft until 2020.

FOR: science (2)

AGAINST: safety (-2)

OVERALL SCORE: 7 to 9 depending on variant

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