NASA successfully tested a rocket booster that it hopes will one day help carry astronauts to Mars.
The booster for what will be the world's most powerful rocket roared to life in a rush of noise and flames during the test on Tuesday at a facility in Promontory, Utah.
It was the last full-scale test for the booster before a scheduled unmanned test flight with NASA's Orion spacecraft in late 2018.
Developing the boosters is a major part of NASA's Journey to Mars initiative, which seeks to send humans to an asteroid by 2025 and Mars in the 2030s.
The boosters will be used in NASA's Space Launch System, which consists of two boosters and four main engines built by an outside contractor.
The boosters will provide more than 75 per cent of the thrust needed for a spaceship to escape Earth's gravity.
NASA scientists were researching how the system will need to be configured to support more weight for more ambitious missions.
"Seeing this test today, and experiencing the sound and feel of approximately 3.6 million pounds of thrust, helps us appreciate the progress we're making to advance human exploration," said William Gerstenmaier, associate administrator for the Human Exploration and Operations Mission Directorate.
NASA retired its space shuttle fleet in 2011 and has since focused its efforts on developing a long-distance craft for eventual human missions to Mars while encouraging the development of private spacecraft to service the International Space Station.
