A rocket stage burns out and falls from the sky towards the sea. Then a parachute opens. While the rocket stage flies over the sea like a paraglider, a helicopter comes up and catches the stage in the air. That should happen in the future with the Rocket Lab electron rocket. During the last two launches of the rocket, the controlled return of the rocket stage to the Earth's atmosphere was successful. Airborne capture of the missile stage was the last untested step.
For the test, a simulator with the same shape and mass of the rocket stage was dropped by a helicopter. A second helicopter caught her on her paraglider. The main problem is that the helicopter cannot fly over the paraglider without crashing the rotor due to the turbulence of the rotor. Therefore, the paraglider dragged a long line behind it, to which the small pilot glider was attached, which previously pulled the main glider out of its pocket.
To catch the missile stage, the helicopter can now fly far behind the paraglider and catch the towline with a fishing line. With a real rocket stage, the next step would be to return to the ship from which the helicopter took off. However, the test took place off the New Zealand coast and was filmed extensively. On YouTube there are also 360-degree videos from the perspective of Rocket level, the End of the fishing line and of the catching helicopter.
There have been many attempts in the past to reuse rocket stages with parachutes. With the Spaceshuttle and the Ariane 5, the process proved to be uneconomical and the refurbishment was too expensive because the rocket stages fell into the sea at a high speed of around 80 km / h despite the parachute. Also on the last flight of Ariane 1 were parachutes on board, but did not open successfully. SpaceX also tried the process at Falcon 1 and the first version of the Falcon 9, but its light rocket stages were destroyed when it re-entered the atmosphere.
The small electron has the physical advantage of re-entry that it has a very large surface area compared to the mass. At the start, this ensures a higher air resistance, but when you re-enter the heat load is better distributed over the individual parts. For this, however, the rocket stage must be kept in a suitable flight position, which was demonstrated on its last flights.