NASA’s study will also try to answer the future questions coming from Congress and the United States incoming president. According to the internal email obtained by the Orlando Sentinel, NASA chief Michael Griffin ordered the shuttle-related study. Griffin had previously been against the delay of the space shuttle’s retirement because it would require extra money and effort and this would get in the way of the development of the shuttle’s incoming successors – the Ares rockets and the Apollo-style Orion capsules which are part of the agency’s "Constellation" program.

However, Griffin had previously opposed the extension of the shuttle’s operations. In April, his main argument in front of a Senate sub-committee was that, by using it for a longer-than-planned period, NASA would put the lives of the astronauts at a much higher risk.

“The shuttle is an inherently risky design. We currently assess the per-mission risk as about one in 75 of having a fatal accident.”

"If one were to do, as some have suggested, fly the shuttle for an additional five years - say two missions a year - the risk would be about one in 12 that we would lose another crew," said Griffin.

However, the internal e-mail clearly says that NASA intends to find out how viable an extension of the space shuttle would be. In order to obtain the money to bankroll the “Constellation” program, the space agency would have to retire the shuttle or ask the Congress for more funds.

"We want to focus on helping bridge the gap of U.S. vehicles traveling to the ISS [International Space Station] as efficiently as possible," John Coggeshall, manager of manifest and schedules at Johnson Space Center in Houston, wrote in the leaked e-mail.

NASA acknowledged the e-mail’s authenticity, but said it is just a premature stage. According to agency spokesperson John Yembrick, NASA has not finalized the parameters of the study regarding the delay of the shuttle’s retirement. "Our plan is still, of course, to retire the shuttle in 2010," he said.

The issue is politically charged. An end of the shuttle program would translate into bad news as it could mean the loss of thousands of jobs and billions of dollars spent to manufacturing the shuttle parts.

Both presidential candidates addressed the matter. Republican nominee John McCain asked NASA to delay the shuttle retirement for at least one year, while Democratic nominee Barack Obama said that NASA should be given $2 billion in order to expand the shuttle’s operations beyond 2010.

The option of getting NASA astronauts to the ISS via Russia's Soyuz system is now regarded with much more concern considering the tense diplomatic relations between the U.S. and Russia over the recent conflict in Georgia.