Cancelled: The Pluto-Kuiper Express

The proposed spaceprobe to Pluto will now definitely not go ahead. The probe that was planned to travel close to the Sun will also be scrapped, as will all of the space shuttle replacement vehicles.

Only the exploration of the Red Planet survives as Nasa is directed to develop a "more robust Mars exploration program".

The space shuttles, currently enjoying the most active period in their history, will be limited to six flights a year. Nasa expects the Russians to play a greater role in the ISS, something that Congress has expressed concern about given the state of the Russian economy.

New direction

The new budget clearly marks a watershed for Nasa. The Bush administration has not been happy about the current $4bn overspend on the ISS. In recent weeks, President Bush had expressed a desire for reform, especially in human spaceflight.

Cancelled soon: The X-34

To this end, it was unsurprising to analysts that George Abbey, director of the Johnson Space Center in Texas, from where the ISS and manned spaceflight projects are run, was recently reassigned to be a special advisor to Nasa's chief Dan Goldin.

Indeed, it is unusual that Dan Goldin, a Clinton appointee, is still in charge of Nasa. A White House statement said he would remain in charge until a replacement was found.

Although Nasa is being given an extra 2% in funding for the coming year, taking its budget to $14.5bn, the increase actually translates into a flat budget. This means there will have to be economies and it is the ISS that will bear the brunt of the cuts.

Quality of science

Plans for a seven-person emergency crew-return vehicle - the X-38 - have been shelved. The crew will have to continue to rely on two three-person Russian Soyuz capsules if there is a need to suddenly vacate the platform. This will limit the ISS's resident crew to six.

Budget direction: "A more robust Mars program"

Sources in Washington say a more specific statement will be made within days about the X series spacecraft, which were being designed as replacements for the space shuttle fleet. The X-33 has already been cancelled and with the X-38 going, there looks to be little future for the X-34.

Also cancelled is the TransHab inflatable module that would be used for living in space. It was hoped that it would be in place by 2005 but one Congressman recently said, "you can kiss it goodbye".

Also gone will be the US-built propulsion module. This means the ISS will have to rely on Russian progress spacecraft to periodically boost the platform's orbit. Scientists have said that these cutbacks are bound to affect the quality of science that will be done on the ISS.

No go to Pluto

The proposed mission to Pluto, the Pluto-Kuiper Express, has been given "zero funding" as has the Solar Probe designed to fly close to the Sun and analyse its "atmosphere". The budget does, however, allocate some funds for propulsion technology research in case of a "future sprint to Pluto".

Astronomers are worried that time is running out for a mission to the small planet. Pluto's atmosphere will freeze out around the year 2015 as it moves further away from the Sun. Similar conditions would not exist on the planet again for another two Earth centuries.

Money has been allocated for future high-energy astrophysics missions meaning a large satellite to detect gamma-rays from deep space should be built.

Proposing the new budget, the White House said it was "a blueprint for new beginnings". Many scientists and engineers, however, will regard the news with sadness and uncertainty. It is clear that the American space effort is heading in a new direction.