NASA counting down for final shuttle launch Canadian astronauts expressed pride Thursday on the eve of NASA's final shuttle launch.
"Many of us feel a great sense of nostalgia today as we celebrate these last historic moments of the space shuttle program," said Steve MacLean, who is one of two Canadians that flew on Atlantis missions.
Four Canadian astronauts are at the Kennedy Space Center for the shuttle launch, as are two federal ministers, Christian Paradis and Gary Goodyear.
Although a potential thunderstorm threatens to delay blast-off, Atlantis is still scheduled to launch at 11:24 ET Friday.
Between 500,000 and 750,000 people are expected to watch the final shuttle launch. STS-135 will be the 33rd space flight for Atlantis and the 135th flight for NASA's venerable 30-year space shuttle program.
When Atlantis lands, it will be retired like the other remaining shuttles and the program will come to an end. Two other shuttles in the fleet of five - Challenger and Columbia - were involved in tragic fatal accidents, causing long delays and putting the entire shuttle program under a cloud for years.
STS-135, like so many other NASA missions, includes a large contribution from Canada, which has benefited greatly from the NASA shuttle program.
One of the mission's chief objectives is to deliver tools and an experiment designed to demonstrate and test NASA's ability to robotically refuel satellites in space. The Canadian Space Agency's Dextre, a two-armed robotic handyman attached to the International Space Station, is a key part of NASA's satellite refuelling efforts.
The second-generation Canadarm is also aboard the International Space Station and will unload cargo - supplies and equipment - from the shuttle for the station.
This will be Canadarm2's 30th shuttle mission since it was installed at the ISS in 2001.
When STS-135 is finished, Canadarm2 will have assisted in 100 spacewalks and unloaded hundreds of tonnes of supplies and equipment in space.
Canadian scientists are also conducting experiments on the four astronauts flying in Atlantis. The experiments relate to skin sensitivity and how it affects balance.
Canadian astronauts have flown on a total of 14 NASA shuttle missions.
While the U.S. has plans for a manned mission to Mars, there appears to be no funding, given mounting deficits. For the forseeable future, American astronauts will have to hitch a ride with the Russians to reach the International Space Station.