Overview

"Recovery" refers to the system that safely lands the rocket on the ground after launch. To achieve this goal, the Recovery Subteam must interface with all aspects of the rocket:

  • Propulsion
    • ensure that the recovery system is within mass budget
    • determine the type and characteristics of the recovery system based on expected altitude
  • Structures
    • ensure that the airframe can withstand the loads from the recovery system
    • ensure that the recovery system fits inside the airframe
  • Avionics
    • ensure that the avionics system is equipped to initiate separation and deployment events, as necessary
  • Payload
    • ensure that the payload is equipped with a recovery system, as necessary

In amateur rocketry, there are several types of recovery systems

Tumble

Tumble recovery is the simplest system. At apogee, the rocket separates into several pieces, and the drag from the pieces is adequate to slow the rocket to a safe landing velocity. This method is typically only used in small, light rockets flights to low altitudes.

Streamer

Streamer recovery involves simply attaching a streamer, or long piece of durable fabric, to a falling rocket or component. The streamer serves as a very small parachute. Again, this method is typically only used for light rockets or rocket components.

Parachute

Parachute recovery is the most complicated of these three methods, but the most capable and flexible for larger rockets and higher-altitude missions. In parachute recovery systems, one or more parachutes are deployed from the rocket to provide drag and slow the rocket down to a safe landing velocity.

Basic Recovery CONOPS

Are addressed and described here.

Recovery Components:

  • Drogue Parachute: a small parachute usually deployed near apogee. The purpose of this chute is to start slowing the rocket down without allowing it to drift too far from the launch site. Drogue chutes can take the form of small streamers, small parachutes, or even a reefed main parachute.
  • Main parachute: a larger parachute usually deployed at a lower altitude (acceptable range is typically from 500' AGL to 1200' AGL) after the drogue parachute. The purpose of the main is to finish slowing down the rocket to a safe landing speed (usually less than 20 ft/sec).
  • Webbing: usually polyester woven straps. Can be either flat or tubular. The purpose of webbing is to connect the various separated pieces of the rocket during recovery operations (e.g. connects multiple tubes together, and connects parachutes to the tubes).
  • Nomex: special flame-resistant cloth. Used to protect parachutes and webbing from the hot gas resulting from firing an ejection charge.
  • Ejection charge: a quantity of BP that is ignited to increase the pressure inside the body of the rocket. This pressure separates the rocket body tubes at predetermined points to deploy the parachutes.
  • Quicklinks: delightful little carabiners that are used to connect components.
  • Electronic Match (e-match): two wires with a bit of pyrogen at the tip. When a potential difference (voltage) is applied across the wires, the pyrogen ignites. e-matches are often used to ignite ejection charges.

General Recovery Tips and Lessons Learned:

  • ALWAYS quicklink Nomex and loose parts to a quicklink. Leaving components loose on a parachute line will result in a reefed parachute (a parachute that is cinched shut, and cannot open all the way)
  • ALWAYS make sure that quicklinks are completely secured shut, using a wrench.
  • ALWAYS ensure that eyebolts are not only tight with a bolt, but secured in place via:
    • Safety wire, or
    • sealing the threads with some sort of glue (epoxy, superglue, etc.)
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