Space shuttle Discovery is set to launch on its final flight next week, concluding a nearly three-decade legacy as arguably the most historic orbiter in NASA's fleet.
The first of NASA's three remaining shuttles set to retire, Discovery was the third orbiter built and the one launched the most times into space.
Its final mission, STS-133, is scheduled to launch Tuesday (Nov. 2) at 4:17 p.m. EDT (2017 GMT). The launch will mark the Discovery's 13th visit to the International Space Station (ISS) and its 39th trip into space.
"This particular orbiter has served us extremely well," said launch director Mike Leinbach, comparing Discovery to its sister ships Atlantis and Endeavour. "It is the fleet leader. It is going to be hard to see her retire but we need to do what we need to do for the agency and so we'll get on with her final flight and it make it the best one ever."
Discovery will deliver to the station the Permanent Multi-Purpose Logistic Module (PMM), the last U.S. room to be added to the orbiting laboratory to serve as a storage closet for the station's supplies and spare equipment.
Also on board is Robonaut 2, the first humanoid robot to fly in space designed to assist astronauts inside and eventually outside the outpost.
Scheduled to last 11 days, Discovery's last flight will bring its total time in space to more than 360 days – nearly an entire year flying around Earth.
"It will have flown about a year on orbit by the time we are done with it, which is pretty remarkable for a space shuttle," said Discovery's commander Steven Lindsey, who is making his third flight on the storied space plane.
A historic 'year' in space
Discovery was built between 1979 and 1983 and made its maiden flight on Aug. 30, 1984, from NASA's Kennedy Space Center in Florida. But before it could depart on the six-day STS-41D mission, Discovery experienced the shuttle program's first pad abort.
A first launch try, attempted two months earlier, ended just four seconds before liftoff. Discovery's three main engines shut down, which was then followed by a hydrogen fire on the pad.
"Gee, I thought we'd be a lot higher at MECO!" radioed mission specialist Steve Hawley from onboard the shuttle at the time, referencing NASA's term for main engine cutoff.
Discovery flew to space five more times— mostly to deploy satellites — before standing down after the shuttle Challenger accident in January 1986.
Two years later, Discovery was the first orbiter to return to flight. Returning NASA's shuttle fleet to flight after a major tragedy is a role Discovery served again 17 years later, in 2005, following the 2003 loss of the orbiter Columbia.
"It was the pathfinder as we put new systems in place, new safety features," said launch integration manager Mike Moses.
A legacy of space firsts
Between its STS-26 mission in 1988 and STS-114 return to flight in 2005, Discovery logged 23 more trips to space, making history along the way.
"Quite a remarkable history for Discovery, it's had a whole bunch of firsts," Moses said.
Among those firsts was the first Russian cosmonaut aboard a U.S. mission, the first rendezvous with the Russian space station Mir, the first female pilot and the first crew rotation for the International Space Station.
Discovery also set the record for flying the oldest crew member in history — 77-year-old Mercury-astronaut-turned-U.S.-senator John Glenn — and recorded the highest altitude reached by any shuttle mission.
That shuttle altitude record was set in 1997 during a mission to service the Hubble Space Telescope, a payload it first deployed into orbit seven years earlier.
Discovery, NASA's oldest shuttle still in service, was instrumental to the assembly of the International Space Station, delivering the largest module — Japan's Kibo laboratory — and the final segment for the outpost's "backbone" truss, among other components.
By the numbers
Over the course of its 26 years in service, Discovery has racked up an impressive set of statistics unmatched by any other spacecraft in history.
As it stands today before flying on STS-133, Discovery has logged 142,917,535 miles circling the Earth a total of 5,628 times.
It has carried 183 astronauts and cosmonauts to and from space, filling 246 seats on 38 missions.
And Discovery docked with space stations 13 times: once with the Mir outpost and 12 times with the ISS.
All these numbers add up to a historic legacy, STS-133 mission specialist Nicole Stott said.
"It is an historic thing, I think, that we have such a special vehicle to fly. In addition to the hope we will have a successful mission, in conclusion we will be celebrating the real significance of the vehicle itself," she said.
"We have to look at this [STS-133 mission] as a celebration of just how wonderful Discovery has performed and just how fantastic a team that has put it together and worked to make it happen."