US AMBITIONS to send astronauts back to the moon as a prelude to missions to Mars have been put in doubt by budgetary constraints 40 years after man's triumphant landing on Earth's nearest neighbor.
After the Columbia space shuttle disaster in 2003, former president George W. Bush decided to phase out the shuttle flights by 2003 and set a more ambitious mandate for America in space.
Launched in 2004, the so-called Constellation program aims to take Americans back to the moon by 2020 to use as a launch pad for manned voyages to Mars.
Without renouncing those objectives, President Barack Obama has named a commission of experts to review the US manned space flight program and make recommendations by the end of August.
The space shuttles, which have carried crews of astronauts into space since 1981, were conceived as reusable vehicles to transport heavy, bulky equipment into Earth's orbit, primarily for the construction of the International Space Station.
But the shuttle has kept the United States stuck in a low orbit for too long at a time when other countries like China are emerging as rivals in space, argues Michael Griffin, the former NASA chief who championed the Constellation program.
But NASA's budget is not big enough to cover the cost of Constellation's Orion capsule, a more advanced and spacious version of the Apollo lunar module, and the Ares 1 and Ares V launchers needed to put it in orbit.
Constellation is projected to cost about 150 billion dollars, but estimates for the Ares 1 have skyrocketed from 26 billion dollars in 2006 to 44 billion dollars last year.
Meanwhile, a group of active and retired NASA engineers, who are critical of the Constellation project, have been working in their spare time on a parallel project dubbed Jupiter Direct.It envisions using the Orion capsule but replacing the Ares launchers with a family of launchers with common components based on existing shuttle technology. -- AFP