Space buffs from Tokyo to Indianapolis were disappointed and frustrated over the delay in launching Space Shuttle Discovery (search) amid concerns over a faulty fuel-tank sensor.

The mission was put off at least until Saturday.

"Again?" Emi Tanaka, 26, said in dismay after trekking to a giant screen in downtown Tokyo with three other friends after a late night of work. The group had hopes of watching the liftoff around dawn, Tokyo time. A flight targeted for late May had earlier been set back by two months.

The launch had been set for live screening at the busy plaza in Tokyo's Shinjuku district (search) and on local TV networks.

The inclusion of Japanese astronaut and local celebrity Soichi Noguchi (search) in the shuttle crew of seven had boosted interest for this mission in Japan.

In the United States, NASA (search) had electronically linked with at least six museums to show the launch live on giant screens. The space agency invited teachers and schoolchildren — many of them from disadvantaged inner-city and rural schools — to the Kennedy Space Center. For weeks, NASA has been promoting what the agency calls its "Return to Flight" outreach program.

"We're encouraging these students to pursue math and science careers," said NASA's chief education officer Adena Williams Loston. "They will be the Mars walkers."

Discovery's launch would mark the first shuttle flight since the Columbia tragedy 21/2 years ago, when the spacecraft disintegrated during its rapid descent toward Cape Canaveral, Fla., killing all seven astronauts aboard.

Even educators could not hide their apprehension.

"This now makes me a little nervous," said Deb Lawson, Spacequest Planetarium coordinator at the Children's Museum of Indianapolis. "Coming back from any kind of a tragedy and being able to accomplish something major is extraordinarily important."

After the scrub, space agency officials and VIPs tried, but failed to hide their disappointment.

"All I can say is shucks," deputy shuttle program manager Wayne Hale said as he sat among grim-faced NASA managers at a news conference.

U.S. Sen. Bill Nelson, a Florida Democrat, flew on shuttle Columbia in 1986 and experienced four scrubs before launch. He said Discovery's crew was bound to be disappointed, but only briefly.

"Then you realize you don't want to be launched with a problem," Nelson said.

The space agency has until the end of July to launch Discovery, after which it will have to wait until September — a window dictated by both the position of the space station and NASA's desire to hold a daylight liftoff in order to photograph the shuttle during its climb to orbit.