Weather plays killjoy for NASA's flying saucer launch

First high waves in the Pacific Ocean and now ill winds are playing spoilsport for the launch of NASA's "flying saucer" from a test range in Hawaii.

NASA had to postpone the balloon-borne launch of its rocket-powered craft from a test range in Hawaii repeatedly due to weather concerns, NBCNews.com reported.

The saucer-shaped Low Density Supersonic Decelerator (LDSD) is designed to demonstrate technologies that are likely to come into play for delivering heavy payloads to Mars.

The craft is equipped with an inflatable, doughnut-shaped shield as well as a super-strong parachute that should slow the LDSD down from supersonic speeds during descent.

A high-altitude balloon has to carry the LDSD aloft to a height of 120,000 feet from the US Navy's Pacific Missile Range Facility on the Hawaiian island of Kauai. The LDSD would be dropped from there, and then its rocket engine would be fired to take it even higher, upto 180,000 feet.

On the way up, the LDSD would hit a top speed of Mach 4, or four times the speed of sound. On the way down, the doughnut-shaped cushion, called the Supersonic Inflatable Aerodynamic Decelerator (SIAD), would be inflated to a diameter of 20 feet.

The SIAD is designed so that atmospheric drag slows the craft down from Mach 3 to about Mach 2.4.

The test parachute would then unfurl to slow the descent even more, so that the LDSD platform falls gently into the Pacific Ocean for recovery.

NASA said such drag devices should be capable of delivering two to three tonnes of payloads safely to the Martian surface. Current technologies limit NASA's Mars payloads to about a tonne.

The LDSD's first flight test took place a year ago and successfully tested the inflatable drag shield. The parachute, however, tore itself apart, resulting in a harder-than-expected splashdown.

Since then, the parachute has been redesigned to be stronger and much more robust.

This year's follow-up test could have taken place earlier this week. But the waves in the Pacific were too high to ensure the safety of the crew members who would have to recover the LDSD after splashdown.

The waves settled down later in the week, but then winds became a concern.