Parachute Research Group
The Parachute Research Group (PRG) works on expanding and improving the already available recovery systems, while coming up with new concepts. PRG has worked on many different projects in the past, such as SPEAR, Stratos IV and project Aether. The team’s current projects are ADEPT, PIP and R2B.
Team leader: Wesley Toussaint
Secretary: Wim Jodehl
Treasurer: Felix Lagarden
ADEPT: Isabelle Joosten (project leader), Anna Stolk, Bram Koops, Kevin Wibowo, Rohit Roy Chowdhury, Sebastian Oliver Scholts, Wesley Toussaint
PIP: Wim Jodehl (project leader), Anna Stolk, Harold Rutten, JJ Perry, Nachiket Dighe, Takayoshi Nakagawa, Wesley Toussaint, Xander Bonenkamp
R2B: Juan Pablo Ávila (project leader), Anthony Cummins, Eugene Wu, Felix Lagarden, Hilbrand Rustema, Santiago Armada Gamboa, Tomás Dias, Tomás Raposo
Current Work
Alternative Decelerator & Alternative Parachute Testing (ADEPT)
ADEPT (Alternative Decelerators and Experimental Parachute Testing) is PRG’s experimental research and development department, working on multiple smaller recovery-related projects. Through literature study and testing, the team aims to create a solid knowledge base for future DARE missions to build upon. Past projects include the characterisation of ringsail and cross parachutes, the development of a pressurised ballute system, and testing of a hot gas deployment device. Currently, the team is researching rotofoils and vortex ring parachutes.
Parachute Investigation Project (PIP)
During the development of Stratos III, the team found that there is a lack of opportunities for testing parachutes. The team has the Open Jet Facility (OJF) of Delft University of Technology available for testing, but with its top speed of 30 m/s, parachutes cannot be tested at the desired dynamic pressures. For this the team looked at flight tests, however, there were no launchers available that could reliably perform a high dynamic pressure test. Therefore, the team started the development of the PIP launcher.
PIP I was launched in September of 2019. It was a partial success, recovering the booster section but not the test section. PIP II was an improved and more aerodynamic rocket, which was to have been launched in March of 2020 but was cancelled due to the COVID-19 pandemic. A slightly redesigned version, PIP II+, was eventually launched in March of 2022 but failed to separate or deploy either of its parachutes. PIP III was heavily redesigned, with an all new booster section and separation mechanism, as well as a carbon fibre parachute mortar taken from SPEAR. It was launched successfully in March of 2023. Currently the team is working on a further improved PIP IV, as well as a second flight of PIP III carrying R2B. Both flights are planned for March of 2024.
Return to Base (R2B)
In windy conditions payloads under parachutes can drift far away after deployment. For the Stratos missions recovery by boat takes a significant amount of time , during which the payload drifts even further. To mitigate this risk PRG has been working on a steerable parachute that allows the payload to fly to a predefined landing location or area.
While a typical parachute is great at slowing down a payload, it has one major disadvantage: it can’t be controlled. The aim of R2B is to develop a steerable, parafoil-like parachute that allows for a controlled descent. Using such a parachute and control system comes with its own set of challenges, however, the benefits justify the additional complexity. A parafoil makes it possible to increase the rate of descent, while still being able to perform a soft landing, thus reducing the risk of excessive wind drift. Additionally, the parachute can be steered towards a given area, which allows for quicker and easier recovery of the payload after touchdown.
Past Work
Capsule Team
The PRG team came from the capsule team, which started out as a sub-team of the Stratos II project. In this project, the team was responsible for the structural integrity of all the components above the engine as well as for the recovery system. The main components that were designed and produced were the glass fibre nosecone shell, the payload section and a dual-spring-deployed parachute system.
The whole capsule section was designed with numerous iterations and tests along the way. Eventually, the final design for Stratos II and Stratos II+ was developed. This was composed out of a double clamp band system held together by spring steel. At predetermined moments this steel band would release, deploying the drogue and the main parachute, respectively. On top of this dual parachute system was the payload section, with a U-shape rack housing the external scientific payloads. To finalize the capsule, the inboard electronics were housed in the top of the nosecone, combined with an antenna for data telemetry and video down-link
CanSat V7M
After the Stratos II+ flight, many team members left the society to graduate. This meant that a young and new team was tasked with the continuation and the development of the Aether recovery system. The team decided to build a modified version of the famous DARE CanSat launcher to test the Aether recovery concept. The flight was successful for most of the subsystems. However, a broken line caused the rocket to crash. More information on the flight can be found here.
Aether
After Stratos II+ the next large-scale project within DARE is project Aether. This project is a collaboration between multiple teams of which the PRG team is one of them. PRG is responsible for the complete recovery system of the rocket.
The recovery section was designed as a two-stage parachute system: a Hemisflo ribbon drogue chute and a cruciform (cross) main parachute. The drogue parachute is deployed sideways from the rocket from a mortar: a high-pressure CO2 vessel that deploys the drogue chute a high-speed. At a predetermined altitude an explosive bolt will be activated so that the main parachute is deployed.
In March 2017 the project got delayed due to technical problems. This allowed the team more time to develop and improve the sub-systems of the rocket. Just after the summer of 2017 the team rapidly expanded with multiple new members, most from DARE’s first-year project. This allowed the team to start the development of new innovative systems.
Stratos III
The nosecone of Stratos III will be recovered because all payloads and important flight data will be stored there. The motor and tank are discarded since it would increase the recovery system mass significantly. The recovery of Stratos III will happen after the rocket has reached apogee. After the apogee, the tank will separate from the nosecone. This separation will make the recovery of the rocket easier since the nosecone will go into a flat spin that will cause an increase in drag.
Because the nosecone will be spinning, a large parachute cannot be deployed, since it would entangle with the nosecone and therefore, it would not inflate. To stop the spin, a small drogue parachute will be deployed. This drogue parachute is made from Twaron, a light and strong para-aramid material. Furthermore, to ensure that the lines of the drogue do not entangle, a cold gas deployment device (CGDD) is used. This system will shoot the drogue at a velocity of 20 m/s.
At about 1000 meters, the main parachute will be deployed. This parachute will be pushed out by a spring system since the drogue ensures there are soft deployment conditions. Once the main parachute inflates, it will decelerate the nosecone to below 20 m/s for a safe water landing.
Stratos IV Recovery Bay
After the flight of Stratos III, DARE went on to find a new challenge. This challenge soon became to become the first student build rocket to reach space. PRG was, just like for Stratos III, assigned for the development of the recovery system. For this, several new members have been recruited and they have worked on the updated design. New features include a pyrotechnic actuation for the drogue deployment device instead of using CO2 and a new Disk-Gap-Band main parachute. The first set of flight hardware has been produced and the systems are currently being tested on subsystem level. The plans for next year include further small scale testing, integration, and system level testing.
Hot gas deployment device (HGDD) – During the development of Stratos III, it was seen that about half the mass of the Cold Gas Deployment Device (CGDD) was in the feed system. Furthermore, from the PDD parts, the feed system was most prone to leaks and failures. In order to mitigate both, the team is investigating the usage of pyrotechnics to deploy the parachute. This Hot Gas Deployment Device (HGDD) houses a small gas generator in which nitrocellulose is used to create pressure. A battleship version out of aluminum has been successfully tested twice. During the summer test campaigns will be performed with a composite casing to move towards the Stratos IV flight design.
Test bench upgrades – To ensure that the wind tunnel tests are done to the standard PRG upholds, it was decided to upgrade the test bench to automatically deploy a parachute and measure the performance of the parachute. First versions of the new system have been used in wind tunnel campaigns in March and May. The system is being iterated to optimize the time necessary for one wind tunnel test, so we’re able to work as efficiently as possible.
Simulations
PRG has two in house developed simulations tools, ParSim and TumSim, that can predict the free fall behaviour of objects. ParSim is a conceptual design tool that can assist in the concept development of a mission. TumSim can predict the free fall behaviour of aerodynamically unstable objects and thus requires more inputs. This makes it a tool used more in the preliminary and detailed design phases. The work resulted “Flight Simulations of the Stratos III Parachute Recovery System” presented at the IAC 2018 in Bremen. During the development of ParSim the team found two additional desirables; a wind model and round earth model. These are currently being implemented in version 4.0.
PyRocket
PyRocket is a medium-sized launcher aiming to both flight-test and film the DARE-developed mortar as well as providing experience on said mortar for various members of DARE. PyRocket1 launched in may of 2023, with a ‘Scottish ringsail’ with reefing for recovery. The mortar fired successfully, deploying the ‘Scottish ringsail’ parachute aboard it. The lines of the parachute however got tangled, never fully inflating the parachute. The onboard camera got blocked during ascent. In September of the same year, a slightly bigger and heavier PyRocket2 flew on the same IRM engine, with the same payload. The mortar fired successfully once more but the reefing did not work, causing a rather hard landing. Luckily all relevant hardware was still intact and some beautiful on-board footage was retrieved, showing the mortar deployment as well. After PyRocket2, the project was ended since the project-goals were achieved.
