Washington: NASA is preparing to mark its 50th birthday in a somewhat sober mood, and even the official date for the legal creation of the space agency - July 29 - will take a back seat to larger celebrations planned for October.

The surviving space shuttles, now 27 years old, are to be retired in 2010, leaving the sole transport to the International Space station in the hands of America's erstwhile space rivals, the Russians.

And while US President George W. Bush in 2004 launched a return-to-moon plan with the idea of using Earth's natural satellite as a launch pad for the exploration of Mars, there's little enthusiasm for such programmes in the current election campaign.

The candidates show little vision for space, the economy lacks the money and generally, Americans' belief in the blessing of progress and the omnipotence of technology also has slid to a new low.

Exploring space is part of the American dream, a mixture of pioneering spirit, the pursuit of new frontiers and cool economic and military calculations.

Along the way, space travel has created modern heroes, like the first US astronauts on the moon, a triumphant experience in the summer of 1969 etched deeply in the memory of every American alive at the time.

In its retrospective on the politically tumultuous year of 1968 - when civil rights leader Martin Luther King and Senator Robert Kennedy were murdered, and riots over civil rights and the Vietnam War shook the country - Time magazine highlighted the one event that warmed every American's heart.

It restored the feeling that the US could still do something right - the circumnavigation of the moon by Apollo 8 with astronauts Frank Borman, Bill Anders and Jim Lovell on board.

On Christmas Eve in that eventful year, millions of Americans watched as the spacecraft circled the moon and the astronauts read the Biblical creation story. "In the beginning God created heaven and earth."

Hollywood could not have done it better.

No one recognised Americans' deep fascination of space flight and its mobilising effects better than the late president John F. Kennedy.

"We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organise and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win," Kennedy said in 1962.

In fact the moon landing, with its flag-planting and patriotic flag-saluting scene, was reminiscent of the staking-off of land in the westward rush - but with military overtones.

The 1969 moon landing marked NASA's zenith. The drawn-out Vietnam War, declining funds, doubt about technological progress, all eroded the US push into space.