NASA astronauts are readying for the launch of shuttle Discovery on Monday to deliver supplies and science experiments to the International Space Station. It is one of the final four missions planned for the shuttle fleet.
NASA officials say the three-day launch countdown began Friday for the launch of Discovery and its crew of seven astronauts.
Shuttle weather officer Kathy Winters says weather conditions should be good for the launch early Monday. She says the launch will occur shortly before the sun rises and casts sunlight on the rising shuttle and the smoke plume.
"The top part of the plume will light up first and it will turn all those rainbow colors that we see when we have launches at dawn or dusk. It should be a beautiful sight," she said.
NASA officials say recent shuttle missions have been crucial in the international effort to expand the space station and extend its lifespan in orbit. Shuttle vehicles can carry large amounts of cargo, which has been needed to deliver and install new modules to the station in recent months.
NASA test director Steve Payne says officials are working to deliver as much equipment as possible, before the shuttle fleet retires later this year.
"This one carries a lot of the experiment racks that we have. Laboratory staff is waiting for them, so we are going to be taking them up," he said. "A lot of the heavy lift has to be carried up with shuttle, so we are taking advantage of all that," said Payne.
Discovery is packed with nearly 12,000 kilograms of cargo, including an Italian-built module that will carry new supplies and science experiments for the International Space Station. Some of the experiments focus on studying how orbiting in space can affect the human body and plant growth.
Mission payload manager Joe Delai says one experiment into muscle and bone loss could also have benefits for human life on Earth.
"The more you study how astronauts can adapt themselves to long-term space flight, when it comes to muscle deterioration and bone loss, really the first derivative is osteoporosis," said Delai. "There are so many benefits that come from the study of that to osteoporosis, and we have been doing that for years," he said.
Delai adds it is important to study how the body struggles or adapts to life in orbit, in order to prepare for long-term missions in the future. He says one current study on tissue damage is being sponsored by the Walter Reed Army Institute of Research near Washington.
"Exposure to microgravity will cause the cells to react similar to the way a wound would act on the human body," Delai added.
After this mission, there are only three more shuttle flights before the fleet is set to be retired. After Discovery returns, it will be readied again to perform the final shuttle flight in September.