In a leaked e-mail intended for top advisors, NASA chief Michael Griffin last month lamented the mandated 2010 retirement of the agency's space-shuttle fleet, as well as the likelihood that U.S. astronauts will be absent from the International Space Station for extended periods in the future.

The Aug. 18 e-mail, first reported Sunday by the Orlando Sentinel, includes candid remarks by the U.S. space agency's administrator.

In one instance, he likened the push to retire the shuttle by 2010 as a "jihad" to shut down the program rather than a decision based on engineering and program management.

Griffin also greatly detailed many of the themes present in the leaked e-mail during a Sept. 2 interview with SPACE.com sister publication Space News. (Click here for a full interview transcript.)

• Click here to see the Orlando Sentinel's report and view Griffin's e-mail.

• Click here to visit FOXNews.com's Space Center.

NASA plans to replace the space shuttle with its Orion Crew Exploration Vehicle and its Ares I rocket booster, but the new space transportation system is expected to begin manned flights no earlier than 2014, leading to a long gap in U.S. spaceflight capability.

Part of the reason for the hiatus, NASA officials have said, has been a limited budget that last month forced NASA's Constellation program, which includes Orion and Ares booster development, to push back its internal manned launch test target by a full year.

"In a rational world, we would have been allowed to pick a Shuttle retirement date to be consistent with Ares/Orion availability, we would have been asked to deploy Ares/Orion as early as possible (rather than "not later than 2014") and we would have been provided the necessary budget to make it so," Griffin wrote in the e-mail.

Griffin also expressed frustration over the likelihood that Congress would not extend the agency's ability to buy seats and cargo space aboard the Russian-built Soyuz and Progress spacecraft beyond 2011 due to Russia's recent military conflict with its neighbor Georgia.

Without the extension, and with the gap between shuttle retirement and start of Orion operations, there will likely be long periods in which U.S. astronauts and those of NASA partners are absent from future space crews.

In a statement issued after the Orlando Sentinel posted Griffin's e-mail, the space agency administrator stressed that the memo alone lacked the appropriate context.

"The leaked internal email fails to provide the contextual framework for my remarks, and my support for the Administration's policies," Griffin said the NASA statement. "Administration policy is to retire the shuttle in 2010 and purchase crew transport from Russia until Ares and Orion are available."

NASA's approval to fly U.S. astronauts and cargo on Russian spacecraft comes under an exemption from the Iran-North Korea-Syria Non-proliferation Act (INKSNA), necessary because Russia provides civilian nuclear technology and expertise to Iran.

In the leaked e-mail, Griffin states that ongoing tension between Russian and Georgia would likely prevent Congress from approving any exemption extension that would allow NASA to pay for additional Russian spacecraft.

"We might get relief somewhere well down the road, if and when tensions ease, but my guess is that there is going to be a lengthy period with no U.S. crew on ISS after 2011," Griffin wrote.

He also added that Russia's Federal Space Agency could operate the $100 billion space station without the U.S., and stressed that NASA would take no measures to force the country to allowing U.S. use of Soyuz and Progress, such as denying access to U.S.-built station power systems or other hardware.

"Practically speaking, the Russians can sustain ISS without US crew as long as we don't actively sabotage them, which I do not believe we would ever do, short of war," Griffin wrote.

"We need them," he later added. "They don't 'need' us. So we're a 'nice to have.'"

In his Sunday statement, Griffin stressed that the space agency does in fact have the support of the Bush administration for the INKSNA exemption.

"The Administration continues to support our request for an INKSNA exemption," Griffin said in the statement. "Administration policy continues to be that we will take no action to preclude continued operation of the International Space Station past 2016."

Last week, Griffin called on shuttle program managers to begin looking into what would be required to extend the space shuttle fleet's service beyond the current 2010 retirement date.

NASA officials said the study was intended for preparation uses only in order to ready the agency to answer any space shuttle program-related inquires from the new incoming president and administration.

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