Swiss-based skydiver Marc Hauser is a real-life Superman.

He set the world record for the fastest forward tracking skydive in 2012 when he flew horizontally through the air at a ground speed of 304 kilometres per hour.

Not content with that achievement, he thought he could go even faster. What would happen if he had a tailwind?

Marc recently conducted that experiment by jumping out of a balloon into the fastest tailwind he could manage — the jet stream.

The plane accompanying the balloon got this shot just before Marc jumped. ( Supplied: Claudio von Planta, jetstreamsuperman.com )

The jet stream is the continuous stream of high-altitude, superfast wind that circles the planet.

It's one of Earth's giant conveyor belts, and migratory birds and commercial airlines use it to get around.

And it's fast! Technically the speed of the wind has to be above 100kph, or it's not a jet stream. And no skydiver had jumped into that kind of wind, at that altitude.

"I have always wanted to be a superhero," Marc said.

"And that's very hard when you're a chicken like I am. Because superheroes always fly, and I'm scared of heights.



"At 18 I started gliding, followed shortly thereafter by skydiving. Then along came powered flight and aerobatic flying.

"But the main thing was always flying, flying like a bird, flying as if I were really born to fly."

The day of the experiment

After years of planning, Marc's jet stream experiment became a reality one early morning in a small town in the middle of New South Wales.

It was 5:30am on June 30, 2018 at the Condobolin showgrounds when Marc finally climbed into the basket of the hot air balloon that would take him to the jet stream.

Once there, he planned to launch himself out of the ballooning and break his own world record.

Marc and his balloon crew on the ground at the Condobolin showground. ( Supplied: Claudio von Planta, jetstreamsuperman.com )

The jet stream is 7,300 metres above sea level, and pretty much the limit of what a hot air balloon can do.

For comparison, Mt Everest is about 8,800m tall.

There were three of them in the basket: another skydiver, Tomas Goulburn; the balloon pilot, Steve Griffin; and Marc.

The temperature in the jet stream is minus 40 degrees Celsius, and the team needed thermal protection suits and their own oxygen supplies.

All went well as the balloon drifted upwards until they reached 7,300m, when all four of the balloon's burners suddenly flamed out.

At the same time, Tomas and Steve's oxygen masks began to leak.

Trying to make the best of a progressively bad situation, Steve yelled at Marc to jump: "Go, just go. You need to go."

There was no ceremonial goodbye, no good luck gesture. Marc just jumped.

"I left the balloon like a chicken, like a coward, feeling that I was leaving my two friends behind," he said.

Marc didn't know if his friends would be able to reignite the burners, or if they would lose consciousness due to lack of oxygen. They could be plummeting to their deaths as he was trying to break a world record.

The whole thing had become a nightmare.

Questioning the point of it

In aviation, there is a culture of bravado, and in extreme sports, like skydiving, this is dialled right up. And it's about taking known risks.

Marc had done years of homework to get to that moment when he jumped out of the hot air balloon into the jet stream.

He trained his mind and his body. He tested his equipment. He got the best people in the world helping him, and he thought he had the balance between risk and caution about right.

But what he didn't get right was the point of the jump.

As well as hoping to set a new world record, Marc was jumping in order to draw attention to the untapped energy potential of the jet stream and the possibility of using it to produce electricity, a bit like wind farms on Earth.

The technology is still very much in the experimental phase, and Marc did manage to bring attention to it.

But with the lives of his friends at risk while he was flying through the jet stream to highlight its power-generating possibilities, it no longer felt important enough. It certainly wasn't worth losing his friends for.

And at that moment he no longer cared about any world record.

Marc's descent to the ground took him across drought-stricken landscape for 6km or so to the next town of Forbes, where he landed in a sheep paddock.

His first action after detaching his parachute was to voice mail his team, asking if the balloon and Thomas and Steve were alright.

Up in the balloon, they were still struggling with the burners. But as they descended and the oxygen in the atmosphere increased, the burners turned back on.

Their trip back down to Earth was "interesting", but they landed safely in another sheep paddock. And they were alright.

Even when everyone was safely back on the ground, Marc still did not know if he would do that jump again.

His friends, however, reassured him that he had done a phenomenal thing. No-one before him had ever jumped into a jet stream and he should be proud, they said.

"We'll follow you on any adventure you plan to do in the future," they said.

The team analyse the data from Marc's jump to see if he broke his own world record. ( Supplied: Claudio von Planta, jetstreamsuperman.com )

Did he break the record?

Analysing Marc's flight data in a café later that day led to disappointment.

The numbers showed that he flew slower in the jet stream than he had in still air. His ground speed was only 270kph.

Disappointing, but still a phenomenal speed. No-one else has ever flown 270kph horizontally in a jet stream. It is still Superman fast.

But Marc thinks he could have broken his previous record of 304kph if he'd been concentrating more on his flying and less on the disaster that he imagined unfolding in the basket of the balloon he'd just left.

This experiment leaves behind a question — what is to be gained by taking risks like this?

In Marc's case, where everything nearly came unstuck, he suddenly realised he was risking the lives of his friends to break his own world record. And for what?

The history of aviation is full of such experiments. One of the most important examples is Australian Harry Hawker, who in 1914 worked out the secret of "spin recovery" — how to get an aeroplane out of a fatal spinning dive.

Hawker did this by putting his own life at risk, and as a result, thousands of lives have been saved since.

Marc put his body on the line to try something new, and in so doing pushed the boundaries of our experience and information about the jet stream, about human performance, about mental discipline in extreme situations.

"The whole adventure didn't go 100 per cent according to plan," Marc said.

"And the question was it worthwhile? It's hard to tell.

"Now that everyone is safe and in one piece on the ground its easy to say, yes of course.

"But we were really lucky."