American support remains strong for NASA's plan to complete the International Space Station (ISS), retire its shuttle fleet by decade's end and move on to the Moon and Mars, according to poll results released Monday.

The new survey - the last of a three-part series sponsored by the industry group the Coalition for Space Exploration - found that more than two-thirds of Americans polled support NASA's stepping-stone approach to returning astronauts to the Moon, provided the effort's cost does not exceed more than one percent of the federal budget.

"I think the stability of the numbers over time is probably the most significant thing,"Jeff Carr, chairman of the Coalition of Space Exploration, told SPACE.com of the three surveys. "Our mission is to help broaden the public's awareness of the value and benefits of space exploration."

NASA's vision of space exploration calls for the U.S. space agency to complete ISS construction - which resumed this month during the STS-115 shuttle mission - by 2010, then retire its shuttle fleet to make way for the new Orion spacecraft and its Ares boosters. The next crewed missions to the Moon are slated for 2018 under the exploration plan.

The Princeton, New Jersey-based Gallup Organization conducted the new poll for between Aug. 2 and Aug. 19 in a telephone survey of 1,000 adults of age 18 or older. The new poll follows similar surveys in March 2006 and June 2005.

In the most recent poll, more than 60 percent of those surveyed stated they supported NASA's human space exploration efforts.

Of the 63 percent of those polled stating that the U.S. should continue to fund NASA's space exploration efforts, 32 percent said exploration should continue at the current funding level, while 22 percent supported a slightly increased level and nine percent preferred a significant funding increase.

NASA's Fiscal Year 2007 budget request calls for about $16.8 billion to support space exploration - a one percent increase over 2006 - and represents a cost of about $58 per year for the average taxpayer, coalition officials said.

The new Gallup poll also found that about 69 percent of those surveyed agreed that the risks of human spaceflight were worth the technical and scientific advancement stemming from such an endeavor. A similar 69 percent also reported little or no concern that the U.S. will lose its space leadership role to China, which has announced plans to send probes to the Moon by 2017, with manned missions to follow by 2024.

"What we're finding is that, simply given the information the public response is extremely favorable," Carr said. "And that's a terrific sign for the vision."