By Jonathan Amos Science correspondent, BBC News
The US shuttle Discovery has launched from the Kennedy Space Center for the last time. The orbiter roared into a bright blue Florida sky, leaving the pad at 1653 local time (2153 GMT).Its 11-day mission will see it deliver a new store room and a sophisticated humanoid robot to the International Space Station (ISS). Only two further flights remain by Endeavour and Atlantis, which Nasa is trying to see concluded this year.The orbiter fleet is then expected to retire to museums.
As usual, huge crowds had gathered on all the approach roads leading to the Nasa facility and on the beaches along Florida's Space Coast - everyone wanting to witness a piece of history.
They all had to wait a little longer than expected - the final countdown was delayed by three minutes as a problem was fixed with the computer system that tracks the shuttle to orbit.
As soon as the issue was resolved, ground controllers restarted the clock and called out to Discovery's crew: "Enjoy the ride". Shuttle Commander Steve Lindsey replied: "We appreciate all your work; and for those watching, get ready to witness the majesty and the power of Discovery as she lifts off one final time."
Discovery is regarded as the "leader of the fleet", and was entrusted with both return-to-flight missions following the Challenger and Columbia accidents.
DISCOVERY: FLEET LEADER
- It is named after various historic vessels, including James Cook's 18th Century explorer
- Discovery was the first spacecraft to retrieve a satellite and bring it back to Earth
- It has completed more missions than any other vehicle in the space shuttle fleet
- The shuttle visited both the Russian Mir station and the International Space Station
- It carried the Hubble Space Telescope into orbit and made two servicing missions
- Before Thursday's lift-off its total in-orbit time: 352 days; and number of orbits: 5,628
First launched in 1984, this is its 39th outing. When it lands back on Earth in nearly two weeks' time it will have covered a cumulative career distance of 230 million km (143 million miles). That's further than the distance from the Earth to the Sun (149 million km).
Once the shuttles are retired, the plan is for US astronauts to fly to the space station on Russian Soyuz rockets until perhaps the middle of the decade.
A number of American companies then hope to be in a position to sell launch services to Nasa on a range of new vehicles.
The intention is that the agency should put its efforts into leading the development of a large rocket - known as the Space Launch System - that can send astronauts beyond the space station to destinations such as asteroids.
Congress has set out the broad capabilities it expects to see in this rocket and has given a deadline of 2016 for its introduction. However, Nasa has said it cannot deliver such a vehicle in the time and with the budget the politicians have specified.
- R2 will be the first humanoid robot in space. It is designed to show how dexterous robots cope in a weightless environment
- After upgrades and advancements, Nasa hopes R2 can venture outside the space station to help astronauts on spacewalkers
- The expectation is that R2-like robots could one day go into orbit to service communications and scientific satellites
- Similar robots might be sent on deep space missions, where they would experience more extreme thermal and radiation conditions
- Humanoid robots could also help set up Mars camps before astronauts arrive, and maintain the surface experiments after they leave
As well as Steve Lindsey, Discovery's crew includes Eric Boe as the pilot. They are joined by mission specialists Alvin Drew, Michael Barratt, Nicole Stott and Steve Bowen. Bowen was called in late to replace crewman Tim Kopra who was injured in a bicycle accident last month.
A key task will be to deliver the Italian-built logistics module known as Leonardo. The module, which is used as a packing box for supplies in the orbiter's payload bay, would normally return to Earth with every shuttle mission, but for Discovery's flight it will be left on station to provide extra storage space.
Leonardo needed reinforcement if it was to be permanently left at the ISS
Leonardo's retention on the ISS represents yet another remarkable achievement for Thales Alenia Space in Turin, which has produced most of the pressurised volume, or living space, on the US side of the platform. Appropriately, Italian and European Space Agency astronaut Paolo Nespoli will be onboard the station to help fit Leonardo into place on the Unity connecting node.
There has been particular interest in a "passenger" being carried up in Leonardo. This is Robonaut 2, or R2, the first human-like robot in space.
R2 is the product of 15 years' research in Nasa and General Motors.
In its current guise, the robot is just a head, arms, and a torso mounted on a pedestal. But the plan eventually is to give R2 some legs to let it move around the station. And in a couple of years, it will also get a body upgrade that should significantly advance its capabilities.
The expectation is that before the decade is out, this robot will be clambering about on the outside of the space station, assisting astronauts on spacewalks. Inside the station, R2 is likely to take on many mundane tasks such as cleaning.
Discovery should arrive at the ISS on Saturday. The first of two spacewalks to carry out maintenance tasks on the exterior of the platform should occur on day five of the mission.
Shuttle Endeavour is expected to fly to the station in April. Atlantis will go no earlier than June.
In the current iteration of Robonaut, Robonaut 2 or R2, NASA and General Motors are working together with assistance from Oceaneering Space Systems engineers to accelerate development of the next generation of robots and related technologies for use in
the automotive and aerospace industries. Robonaut 2 (R2) is a state of the art highly dexterous anthropomorphic robot. Like its predecessor Robonaut 1 (R1), R2 is capable of handling a wide range of EVA tools and interfaces, but R2 is a significant advancement over its predecessor. R2 is capable of speeds more than four times faster than R1, is more compact, is more dexterous, and includes a deeper and wider range of sensing. Advanced technology spans the entire R2 system and includes: optimized overlapping dual arm dexterous workspace, series elastic joint technology, extended finger and thumb travel, miniaturized 6-axis load cells, redundant force sensing, ultra-high speed joint controllers, extreme neck travel, and high resolution camera and IR systems. The dexterity of R2 allows it to use the same tools that astronauts currently use and removes the need for specialized tools just for robots.
One advantage of a humanoid design is that Robonaut can take over simple, repetitive, or especially dangerous tasks on places such as the International Space Station. Because R2 is approaching human dexterity, tasks such as changing out an air filter can be performed without modifications to the existing design.
Another way this might be beneficial is during a robotic precursor mission. R2 would bring one set of tools for the precursor mission, such as setup and geologic investigation. Not only does this improve efficiency in the types of tools, but also removes the need for specialized robotic connectors. Future missions could then supply a new set of tools and use the existing tools already on location.