Extreme athlete Felix Baumgartner hopes to make a second attempt at a supersonic skydive over New Mexico on Sunday or Monday.

Baumgartner aborted his mission Tuesday due to high winds, and his team had hoped the weather Thursday would allow him another try then. But now they're looking at the next break in weather being Sunday or Monday.

What is the sound barrier?

The sound barrier isn't a physical limit. It's the point at which an object starts to travel faster than the speed of sound. At sea level, this speed is about 1,200 km/h.

Once an object reaches this sonic speed, the sound waves it produces aren't fast enough to keep up with it. The air pressure in front builds, creating a shock wave — and the "cracking" sound known as a sonic boom.

Baumgartner is hoping to become the first skydiver to break the sound barrier by jumping from a capsule floated 37 kilometres into the stratosphere by a 55-storey helium balloon.

The jump was postponed due to wind Monday, then aborted at the last minute because of wind gusts Tuesday.

The balloon is so delicate that it can take off only if winds on the ground are 3.2 km/h or less.

Jump would set 4 new world records

The feat, sponsored by energy drink maker Red Bull, is supposed to be broadcast live on the internet, using nearly 30 cameras on the capsule, the ground and a helicopter.

A 20-second delay would allow organizers to shut down the feed if an accident occurred.

The plan is for Baumgartner to make a nearly three-hour ascent and then take a bunny-style hop from the capsule into a near-vacuum where there is barely any oxygen to start his jump.

The jump poses many risks. Any contact with the capsule on his exit could tear the pressurized suit. A rip could expose him to a lack of oxygen and temperatures as low as 55 degrees below zero. It could cause potentially lethal bubbles to form in his bodily fluids, a condition known as "boiling blood." He could also spin out of control, causing other problems.

While Baumgartner hopes to set four new world records in all when he jumps, his dive is more than just a stunt.

His free fall should provide scientists with valuable information for next-generation spacesuits and techniques that could help astronauts survive accidents.