Bad weather has led the US space agency to once more postpone the first test of the largest parachute ever deployed.

If conditions improve, the test flight of the flying saucer, known as the Low-Density Supersonic Decelerator, will be broadcast live on NASA's jet propulsion Ustream page beginning at 1.30pm local time on Friday (3.30am AEST on Saturday).

An artist's rendering of NASA's Low-Density Supersonic Decelerator (LDSD), designed to test landing technologies for future Mars missions. Credit:NASA/JPL-Caltech

"A line of rain showers developed overnight moving towards the launch site, which result in unstable wind conditions near the surface that would prevent the launch of the balloon," NASA said.

High ocean waves have already forced several delays to the launch, originally set for early this week.