For 50 years NASA has led the world in space exploration. Much of the scientific knowledge about the moon, our solar system and the universe has come from the dedicated scientists, administrators and personnel working for NASA. VOA's Paul Sisco takes a look at the agency celebrating its golden anniversary with an eye on its uncertain future.

For 50 years NASA has led the world in space exploration

The U.S. space agency NASA has been promoting and celebrating its fiftieth anniversary with events all year, but the current state of the agency and its uncertain future has many concerned. U.S. Senator Bill Nelson is Chairman of the Senate subcommittee that overseas NASA.

"NASA is at a crossroads," Nelson said, "and that crossroads has to do with whether or not we will commit the political will and the national resources in order to achieve the dream of our continued space program, both the human space program and the unmanned space program."

NASA's glory days and the accomplishments of its manned space program are well known and documented.

For many years after its inception, the agency thrived thanks to substantial federal funds.

Space consultant and former NASA manager Alan Ladwig says that is no longer the case.

"During the high point of the Apollo program, NASA represented four percent of the federal budget," according to Ladwig. "Today it represents six-tenths of one percent."

The space shuttle has been flying American astronauts into space since 1981. But the aging fleet is to be retired in 2010 and there could be a five-year gap before a replacement vehicle is ready. President Bush and NASA now have their sights on returning to the moon, future missions to Mars, and the building of new space vehicles to accomplish the tasks.

But again, says Senator Nelson, the problem is money.

"NASA can not do both the space shuttle program and the start of the new Constellation program, without additional money, which is what has caused the two not to overlap, and has us facing a five year gap in not flying humans in space," said Nelson.

Glenn says NASA has been cutting back shuttle flights to save cash

While those vehicles are being built and tested America will not be able to get to the space station on its own, a situation that angers former astronaut and Senator John Glenn.

"They are so strapped for money at NASA that they are having to cut the shuttle flights to save enough money to complete the station," Glenn said. "I think it's a little ridiculous when we're cutting to the point where our transportation to our space station is gone and we have to contract after 2010 with the Russians to put us up to our station."

Astronauts will always look to space exploration with great optimism.

But in this, NASA's golden anniversary year, the U.S. space agency clearly sees significant challenges on the horizon.