Purpose
The Hermes recovery system follows a dual-separation, dual-deploy architecture. The drogue deployment event is initiated at apogee by a pyrotechnically operated piston. The main parachute is retained via a Tender Descender until approximately 2,000ft. Subsystem and component designs, testing procedures and results, and research is summarized here.
Requirements
The following requirements come from the DTEG.
| Requirement | Description | Component | Compliance |
|---|---|---|---|
| 3.1 | Dual Deploy CONOPS | Architecture | Vehicle is Single-Separation Dual-Deploy |
| 3.1.1 | Apogee Event | Avionics | System can accurately detect Apogee |
| 3.1.1 | Drogue Descent Rate | DGB Parachute | Descent velocity is between 75-150 ft/s. Compliance is TBD |
| 3.1.2 | Main Event | Avionics | Event Shall be no higher than 1500 ft AGL. Exemption Obtained. 2,000 ft AGL acceptable for larger parachute |
| 3.1.2 | Main Descent Rate | Main Parachute | Landing velocity is less than 30 ft/s. |
| 3.1.4 | Torsion Relief | Swivels | Swivels are implemented to relieve recovery system to airframe torsion |
| 3.1.5 | Drogue Color | DGB Parachute | Drogue is orange and white |
| 3.1.5 | Main Color | Main Parachute | Main Is red and black. |
| 3.5 (4.0) | Energetic Devices | Firebolt | TBD |
| 3.5 (4.0) | Energetic Devices | Tender Descender | TBD |
| 3.6 | Testing Compliance | Procedures | EHS and MIT Facilities procedures followed during all testing |
| 3.6.1 | Successful Ground Test | Architecture | Flight components have a successful ground test prior to flight |
| 3.6.2 | Successful Flight Test | Architecture | Flight Test Indefinitely Postponed |
| 4.2 | SRAD Pressure Vessel | Piston | TBD |
| 6.2.2 | Recovery Attachment Points | U-Bolts | U-bolt made of steel other than stainless steel |
...
The design considerations associated the Hermes recovery system are summarized in the following pages:
- Webbing Lengths
- FireBolts
- Shear Pins
- Hermes Parachutes
- HADES ("Piston-Cup-Diaphragm" System)
- Packing Procedures and Volumes
Procedures
Testing
Component Level Testing
- Tender Descenders
- Piston
- Instron Testing
Ground Testing
A general description of ground tests can be found here.