Design, development and testing of a compact lightweight capsule recovery system

Paper number

IAC-08.D2.3.5

Author

Mr. Gerrit Hausmann, Dresden University of Technology (DUT) / Technische Universität Dresden, Germany

Coauthor

Mr. Maxim Mironov, SSAU, Russia

Coauthor

Mr. Fabio De Pascale, Delta-Utec SRC, The Netherlands

Coauthor

Mr. Michiel Kruijff, Delft University of Technology, The Netherlands

Year

2008

Abstract

This paper reports about the development and test of a recovery system for small capsules, originally developed for the YES2 satellite launched in 2007, that included a miniature re-entry capsule. The system includes a beacon and parachute, an activation system, and a compact spring-based parachute ejection system, initiated by a pyrotechnic device. 
Design challenges were low mass (few hundred grams), low volume (the ejection system is the size of a shoe-polish box) and (de)installation possible with minimal access. High ejection energy was required (about 15 J) to eject the parachute even reliably from a spinning fast-dropping capsule. The system can be used for recovery of lightweight capsules and probes released from orbit, sounding rockets or high altitude balloons. 

Especially the development of the ejection system turned out to be quite complex requiring several innovations. Given the tight allowance of space and mass inside the 40 cm, 6 kg YES2 capsule, the system had to be both compact and lightweight. Parachute and ejection system are contained in a thin PET cylinder. A hot gas generator solution for ejection was tested but rejected from point of view of safety and reliability. To deliver high energy density with the simplest possible mechanical system eventually a spring-based system with unique release modus was developed. This system consists of two concentric springs mounted in between two thin aluminum plates. After compression, the two plates are held together by a central bolt, which passes through a pyrotechnical cutting device. When the firing pulse is given, the central bolt is cut, releasing the springs. The outer spring, short and strong, now pushes the parachute through the capsule’s rear heat shield, while the larger outer spring jettisons the parachute out far enough for safe deployment.
With the parachute’s force transferred through the outer plate instead of directly to the capsule, the spring system also acts as a shock absorber, losing energy by deformation of the spring.
The beacon employed is a low-power ARGOS beacon, which uses the constellation of ARGOS satellites to provide worldwide ground location within hours over the internet. Beacon and parachute are initiated through logic using a pressure sensor and timer. The system is developed to be crash-proof, such that the beacon operates also in case of parachute failure.
The overall design approach has been hands-on, goal oriented and pragmatic, due to time and budget constraints. Pros and cons of this approach are highlighted.

The paper reports on design, trade-offs and the successful qualification of the various systems involved and the mechanism in particular. Unfortunately the capsule has not been recovered yet, but analysis of its whereabouts and possible reasons of lack of beacon sigal will be discussed. Nevertheless, a reflight is foreseen, as the successful qualification and overall mass and dimensional properties make the recovery system an attractive option for future small capsules and probes.

Abstract document

IAC-08.D2.3.5.pdf

Manuscript document

IAC-08.D2.3.5.pdf (🔒 authorized access only).

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