The 2004 NASA budget proposal from President Bush -- prepared before Saturday's Columbia shuttle disaster -- couples an increase in funding with criticism of management of the shuttle program.

The budget calls for NASA's budget to rise 3.1 percent to $15.5 billion in 2004, including a 23.9 percent boost for the shuttle to $3.97 billion.

However, the breakup of Columbia, killing seven astronauts, places all such plans in question as the agency girds to determine the disaster's cause and to answer questions from Congress and others about past and future spending priorities.

Questions are already being raised about funding for the space shuttle program, which was cut by 1.9 percent in the 2003 budget.

"Inevitably, there will be a discussion out of this about how much NASA should be funded, should there be another orbiter built, and in fact, has it been so poorly funded in recent years that maybe, just maybe, it wasn't as safe as it should be?" Sen. Bill Nelson, D-Fla., who flew aboard Columbia in 1986 as a House member, said Monday.

The proposed 2004 increase was because of cost-related delays in the development a reusable launch vehicle, which will require the shuttles to keep operating longer than planned, said the president's budget, released Monday morning. Columbia was the oldest shuttle in service.

"However, past management of shuttle investments suffered from unclear planning and cost overruns," the budget says. It calls on NASA to reform its shuttle investment and planning management.

Major initiatives in the NASA budget include nuclear power for space vehicles, dubbed Project Prometheus, and high-speed communications systems. Project Prometheus -- aimed at vehicles to explore the moons of Jupiter -- is marked for $279 million in 2004 and $3 billion over five years.

Currently, space ships are launched with rocket power, but once in space they rely on momentum to carry them to their goal, since they carry enough heavy rocket fuel to continue accelerating through space. It can take years for a vehicle to travel to Jupiter or other parts of the solar system.

Development of nuclear fusion or fission engines would enable a space vehicle to continue increasing its speed once away from Earth, shortening the time needed to reach distant planets. These engines also could provide electrical power instead of relying on solar cells or batteries, making it possible to operate more scientific instruments.

The safety of nuclear engines is likely to come under close scrutiny by people worried about the danger of a launch accident.

The budget also calls for spending $31 million to begin development of a high-speed optical communications system. Such systems, using lasers, can carry much more data than radio waves. The technology is expected to be ready for use in the Mars exploration program in 2009.

And there is a call for $39 million to begin a human research initiative to better understand the health challenges of space flight.

Space science would get a 17.3 percent boost to $4.0 billion, though space flight capabilities would face a small cut, down 0.3 percent to $6.1 billion.

Other spending in NASA's proposed budget includes earth science, $1.5 billion, down 4.6 percent; biological and physical research, $973 million, up 15.5 percent; aeronautics, $959 million, up 1.3 percent, and education programs, $170 million, up 18.0 percent.