As they watched, they saw the light descend to the ground and then extinguish.
The constables immediately steered their car towards the site where they believed the mysterious object had landed.
Upon reaching the place, Hamann and Golkel found two guys standing on the road blocking the cars approach.
The uniformed men assured them that indeed they were.
The two strangers whooped with joy and signaled their wives and children to come out of hiding.
They opened a bottle of champagne and made a quick celebration of their impossible escape.
All escape attempts from communist East Germany were risky, but Strelzyk and Wetzel methods were the most daring.
It was patrolled by fifty thousand armed East German guards armed with automatic weapons and powerful search lights.
Despite the heavy fortification, tens of thousands of East Germans attempted to escape to the west.
Nearly a thousand lost their lives trying to do so.
Peter Strelzyk was an electrician and former East German Air Force mechanic, and Gunter Wetzel was a bricklayer.
They both knew each other for four years before they started discussing ways to cross the border.
They laid the balloon flat on the ground and hung it from a cliff, but without success.
Strelzyk and Wetzel realized that the balloon material was too porous.
The result, however, was the same.
They picked up umbrella covering and various grades of taffeta and nylon.
They determined that umbrella covering performed the best but was also the most expensive.
They instead selected a synthetic kind of taffeta.
This time the balloon stayed inflated and the ropes became taut as it strained to escape.
But their euphoria turned out to be short lived.
The burners went through the gas too quickly, allowing the air to cool and the balloon slumped over.
Wetzel and Strelyzk tried a host of things to improve the performance of the burner.
They used four gas cylinders instead of one, experimented with gasoline and gasoline-propane mixtures.
But the results were still unsatisfactory.
Meanwhile, Strelzyk continued to tinker with the burner.
Strelzyk was now ready to attempt an escape.
He just needed the right weather and wind condition.
Both came on the night of July 3, 1979.
They reached an altitude of 6,600 feet according to an altimeter Strelzyk had made by modifying a barometer.
A moderate northerly wind blew them gently towards the border and freedom in West Germany.
But then, the balloon entered a cloud.
The water vapor in the cloud condensed on the balloon, soaked the material and made it heavier.
It was 20 meters in diameter, and 25 meters tall.
The materials required to sew this humongous balloon now stood at 1,250 square meters.
Wetzel then sewed a third balloon, using over 6 kilometers of thread.
In six weeks the balloon was ready.
It weighed 180 kg.
The gondola, the burners and the two families added another 550 kg.
But with the new bags volume, the men knew that the balloon had the lifting power.
At 100 degrees, the air density is only 3785.4 kg on a volume of 4,000 cubic meters.
Thus, the density difference between the cold and heated air is 1386.6 kg.
That was my lifting power.
The first problem arrived just as they were taking off.
The men had tied the gondola down with tethers to prevent the balloon from floating away prematurely.
Luckily they had brought a fire extinguisher just for such an emergency and the fire was put out.
The temperature was at minus 8 degree Centigrade.
The women and children huddled, shivering on the gondola floor.
The only protection against falling was the clothesline guard rail.
This hole appeared in the balloon immediately after the launch.
As they crossed the border they saw several bright spotlights directed towards them.
Soon the gas ran out, and the balloon started to descend.
They had landed near the town of Naila.
Their half-hour balloon flight had taken them nearly twenty-five kilometers in ground distance.
The town of Naila gave the families apartments and aid to get started.
Wetzel worked as an automobile mechanic and Strelzyk opened a TV repair shop in Bad Kissingen.
The Wetzels remained in Bavaria.
Strelzyk and Wetzels story was made into two movies:Night Crossing(1982) andBalloon(2018).
