For decades, Nasa has depended on the same parachute design to slow spacecraft after they enter the Martian atmosphere, but it needs a larger and stronger chute if it wants to land heavier objects and astronauts.
Weather permitting, a balloon carrying the saucer-shaped vehicle is set to launch from Hawaii.
The vehicle will ignite its rocket engine and climb to 34 miles, and will then inflate a tube to slow itself down from supersonic speeds and unfurl a parachute for a water landing.
Engineers will analyse the data to determine if the test was successful. The test has been postponed several times because of high winds.