Home > Mid-air retrieval

Mid-air retrieval is a technique used in atmospheric reentry when the reentering vehicle is incapable of a satisfactory unassisted landing. The vehicle is slowed by means of parachutes, and then a specially-equipped aircraft matches the vehicle's trajectory and catches it in mid-air.

This is a risky technique, and so is only used when other forms of landing are infeasible. Successful mid-air retrieval requires correct operation of the retrieving aircraft, favourable atmospheric conditions, and successful execution of a tricky manoeuvre, in addition to correct operation of the vehicle itself. Complicating matters, helicopters, which are the optimal aircraft for these operations due to their manoeuverability, are particularly prone to mechanical breakdown. These risks can be mitigated somewhat: for example, multiple recovery aircraft can be used. The need for human aviators to perform a manoeuvre which would normally be classed as a stunt may in the future be avoided by advances in unmanned aerial vehicles.

Notable uses of the technique:

• The early- 1960s era Corona reconnaissance satellite returned delicate film capsules to Earth that required mid-air retrieval by a C-130 Hercules airliftIn logistics and military terminology: An airlift is the act of transporting people or cargo from point to point using aircraft. This can be as ordinary as transporting televisions from one airport to another, or as extraordinary as the Berlin Airlift.er.
• The Genesis mission returned a sample of solar windA solar wind is a stream of particles (mostly high-energy protons ~ 500 keV) which are ejected from the upper atmosphere of a star. In the solar system, the composition of this plasma is identical to the Sun's corona, 73% hydrogen and 25% helium with the that was so delicate that it would have been damaged by a parachute landing, so a mid-air retrieval was planned. Its parachutes failed to deploy, so mid-air retrieval was impossible and the capsule crashed.
• An early design for SpaceShipOne called for a shuttlecockA shuttlecock is a high- drag projectile used in the sport of badminton. It has an open conical shape, with a rounded head at the apex of the cone traditionally made of cork and a skirt traditionally of overlapping goose feathers. For most casual players,-like shape that would have made it incapable of landing independently, necessitating mid-air retrieval. This was deemed too risky, and the final design made the spacecraft capable of independent horizontal landing while cleverly retaining the desired aerodynamic qualities for the early part of reentry.