NASA has postponed the launch of an unmanned spacecraft that is designed to help get humans to Mars, a mission touted as the first step in deep space exploration.

The tiny Orion spacecraft was scheduled to blast off at 12:05 GMT on Thursday with the help of a Delta 4 Heavy rocket, known as the biggest booster rocket in the US fleet. However, weather condition and technical issues prompted several delays and final decision to reschedule the launch for 12:05 GMT on Friday.

"Today's planned launch of #Orion is postponed due to valve issue. Our next possible launch window opens at 7:05am ET Friday," NASA announced on its Twitter account on Thursday.

Al Jazeera's Andy Gallacher, reporting from Kennedy Space Centre in Cape Canaveral, said that the delay was more of a frustrating start to Orion's historic launch than a disappointment.

"Technical issues, high winds and stray boats aside safety is a top proirity for the space agency and there is still a 25-day launch window for NASA's best new hope," said Gallacher.

He said that at the Kennedy Space Center there was "a palpable sense of anticipation for what Orion could achieve and a sense that pride is back in the US space programme".

The conical spacecraft looks similar to the Apollo capsule that took astronauts to the Moon in the 1960s and 1970s, but slightly larger and with modern electronics.

NASA hopes to send an Orion crew to an asteroid corralled in lunar orbit in the 2020s and to Mars in the 2030s.

'Exploring deep space'

Earlier on Thursday, Mike Sarafin, the lead flight director stationed at Mission Control in Houston, Texas said:

"We haven't had this feeling in a while, since the end of the shuttle programme. Launching an American spacecraft from American soil and beginning something new, in this case exploring deep space."

The space capsule is aiming to travel for a distance of 57,800km, 14 times higher than the International Space Station.

This high altitude will give it the momentum it needs for a 32,200-kph, 4,000-degree entry over the Pacific. Those crucial 11 minutes to splashdown is the critical part NASA calls the "trial by fire".

The heat shield at Orion's base, at five metres across, is the largest of its kind ever built. Orion will land in the Pacific Ocean, 1,000km off the coast of Baja, California where recovery teams will retrieve the shuttle.

NASA wants to experiment with the capsule’s most critical parts before it carries out astronauts.

This $370m trial includes the heat shield, parachutes and all the sections jettisoned during ascent and entry.

The capsule will also pass through extreme radiation in the Van Allen belts surrounding Earth, as engineers want to estimate the effects on the on-board computers.

Lockheed Martin Corporation is managing the test flight for NASA.

Sarafin's entire team at Johnson Space Center in Houston is comprised of former shuttle flight controllers.

Gene Kranz, known as the legendary flight director of Apollo 11 and more, will be on hand in Mission Control on Friday.

Source: Agencies