Orion 'Mars ship': The most ambitious venture in Nasa's history offers the best chance of rekindling national excitement over space exploration

The project could revive the excitement and sense of purpose that drove the Apollo programme and the series of moon landings between 1969 and 1972

Forty two years ago this month, Eugene Cernan became the last man to walk on the moon, as he boarded the lunar module Challenger to begin the 250,000 mile journey back to earth. Astonishingly, not since that last Apollo 17 mission has an American space craft designed to carry humans left low earth orbit – the realm of the now defunct space shuttles and the international space station. Until now.

The planned launch of Orion, the craft that one day may take men to Mars may have been delayed. But soon, perhaps as soon as tomorrow, the obstacles of a blocked valve, gusty winds and stray boats offshore from the launch pad at Cape Canaveral will be resolved and Orion will blast into space. The mission will last a mere four hours, and no humans will be on board.

But, carried by a Delta-IV rocket, the most powerful currently available to Nasa, Orion will penetrate 3,600 miles into space, 15 times further away than the space station. It will circle the earth twice, before re-entering the atmosphere at a speed of 20,000 mph. The mission will test the most crucial and dangerous areas of a real Mars mission: launch, the separation of the landing module from the crew module, and re-entry itself, when the temperature of the craft’s protective shield will reach 4,000 degrees Fahrenheit.

Orion however is not merely the latest and most ambitious venture in the history of Nasa, founded in 1958. It offers the best, and maybe the last, chance of rekindling the national excitement and sense of purpose that drove the Apollo programme and the series of moon landings between 1969 and 1972.

As he prepared to leave the moon that December day, near the end of Richard Nixon’s first term in the White House, Cernan loftily vowed that “we shall return, with peace and hope for all mankind.” Later, he predicted that a man would land on Mars by the end of 20th century. “I was a little off on my timing,” he recently and ruefully noted to The Washington Post.

This Orion launch is indeed barely the beginning of the project. Work on it began in 2006. As yet, the vehicle to propel Orion on its way to the red planet does not exist: the new Space Launch System (SLS) rocket will not be ready until 2018, and the first manned test flights won’t happen before 2020. The Mars mission itself is not scheduled until 2030, at the earliest.

In the meantime, space travel has mostly been a mixture of the mundane and the tragic. Yes, there have been miraculous moments, but all involving unmanned flights: the pictures sent back from the surface of Mars by the rover Curiosity, the landing of the European space agency’s Rosetta probe on Comet 67P on 12 November – and last and most awe-inspiring of all, the 12-billion mile (and still counting) journey of Voyager 1, launched by Nasa in 1977, and the first man-made object to leave the solar system and penetrate interstellar space.

Otherwise though, space travel became routine, first with the shuttle programme, then with the international space station (ISS) with which the shuttles regularly docked. The most indelible moments have been been disasters: the January 1986 explosion of the shuttle Challenger shortly after launch, the disintegration on re-entry of its sister craft Colombia, on 1 February 2003, and most recently the crash of the Virgin Galactic prototype. The latter was intended for low orbit space tourism: the ultimate banalisation of space travel.

With the wrapping up of the shuttle programme. Nasa’s fortunes were at their lowest ebb. After the last flight of shuttle Atlantis in July 2011, the US was left without even its own vehicle to reach the ISS.

True, grander schemes intermittently surfaced, most notably President George W. Bush’s 2004 Constellation project that would have seen the expansion of ISS, the return of men to the moon and the establishment of a permanent base there, and ultimately a mission to Mars. But Constellation was scrapped by his successor soon after coming to office (the moon – “We’ve already been there,” Mr Obama said). Instead, a manned Mars mission became the long-term goal.

And so to Orion. Whether the project reaches fulfilment is anyone’s guess. Cost is one obvious consideration, even if the estimated overall price tag of over $30bn is relatively small beer as government spending projects go, spread over two decades. But where untried technology is concerned, civil as well as military, cost overruns are the norm. A future president, faced with his own budget deficit crisis, may conclude that funding flights to Mars is a luxury that can be dispensed with, especially if the mission fails to stir the public imagination.

There are some signs however that public interest is growing. A smaller one is the resurgent popularity of fictional space movies like Interstellar. Another is sheer national pride. Embarrassment and fear at being beaten by the Soviet Union to the first manned orbital space flights spurred President John F Kennedy to set his goal of putting a man on the moon by the end of the 1960s.

The country set such targets, he declared, “not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills.” With Orion, and the challenge posed by China as well as Russia, the same rationale may be taking hold now.