Elon Musk's SpaceX will make a second attempt to deliver one of two docking rings to the International Space Station, a crucial step in enabling US commercial space taxis to ferry astronauts to the orbiting lab, NASA says.
Space Exploration Technologies, or SpaceX, tried last year to deliver a ring for the first time, but the equipment was destroyed during a launch accident.
"I know how critical this is for NASA," Hans Koenigsmann, SpaceX's vice president for mission assurance, said during a press conference on Saturday.
SpaceX's Falcon 9 rocket and Dragon cargo ship are scheduled for launch at 12.45am EDT (1445 AEST) on Monday from Cape Canaveral Air Force Station in Florida.
About 2.5 minutes after liftoff, the rocket's main section will separate, turn around and attempt to land on the ground a few miles from the launch site.
A second docking ring is due to be delivered in 2017, the National Aeronautics and Space Administration, or NASA, said.
Owned and operated by Musk, the technology entrepreneur who founded Tesla Motors Inc, SpaceX is developing rockets that can be refurbished and re-used, potentially slashing launch costs.
So far, it has successfully landed a Falcon on the ground once and on an ocean platform in three out of its last four attempts.
Landing the rocket is a secondary goal. The main mission is placing the Dragon capsule into orbit and sending it on a two-day trip to the station.
The metal docking ring, built by Boeing Co, 2.4 metres in diameter.
After its attachment to a berthing port on the station, it will serve as a parking space for commercial spaceships under development by SpaceX and Boeing. The manned craft are scheduled to begin test flights next year.
