For this project we needed a LiDAR that could support us in detecting the ground when approaching the earth at speeds at around 80km/hr – allowing for a sufficient reaction (time of three to five seconds) to perform a controlled and safe landing.
“We needed the best, smallest and most compact LiDAR out there”
“It was the only LiDAR that we found that was small enough and that had enough documentation that we can actually use”
– Clemens Riegler, ChairmanWüSpace e. V.
WüSpace is a non-profit association based in Würzburg, Germany and consists of a team of students working on aerospace projects. The main goal is to pass on the knowledge they gain in their projects to more students, enabling them to realize their projects and share knowledge. WüSpace was founded in 2019 and started with two projects. The project this story specifically focuses on is Daedalus2, the successor to the project Daedalus which was the association’s founding project.
What is project Daedalus 2 about?
Daedalus2 is being developed as part of the REXUS/BEXUS programme by the DLR, SNSA and ESA. The ESA programme aims to provide students with an opportunity to actually work on flight hardware and not simply their university studies – subsequently learning from these experiments. Students are invited to apply for a rocket on submission of an experiment idea. If ESA approves the experiment concept, the student is given a rocket. The Daedalus2 team consists of 38 students working on the project in their free time.
For their project, team Daedalus2 designed and developed a “SpaceSeed” which was built to be ejected from a rocket once the rocket reaches the outer limits of the earth’s atmosphere or roughly 80km above the surface of the earth. The key innovation in this design is that once ejected this SpaceSeed can, through a combination of propeller rotation and ground sensors, decellerate and reduce its velocity for a controlled, safe landing.
The main goal of Daedalus2 is to show that one can actually descend an experiment capsule from space without a parachute. Similar to the rockets of Jeff Bezos, Daedalus2 involves the launch of a rocket within which is a small experiment capsule (SpaceSeed) – capable of doing specific measurements of the atmosphere and collecting various samples. The SpaceSeed collects samples and measurements, descending back to earth safely without the use of a parachute. This project aims to effectively demonstrate that there are other more convenient and controlled ways of descending a space capsule to earth – through the use of autorotation, a rotor and a ground sensor.
It is very difficult to send a space capsule just into space and then have it descend back to earth in a safe and controlled manner. The most commonly used approach to this problem is parachutes, which pose a challenge as they tend to get tangled up. The main objective of Daedalus2 is thus to demonstrate that safe, controlled and convenient landings are possible through methods other than the use of parachutes.
Another challenge the team had to contend with was ensuring that all components and electronics could successfully function at extremely low temperatures – as experienced in space. Happily, through extensive testing of all components in the climate chamber of the JMU Wurzburg, all components were able to meet this requirement – including the LightWare SF30/C LiDAR which is designed to go as low as 0° but was able to continue to function at temperatures of -20°.
The team of 38 students are divided up into four distinct teams. The Mechanics Team are responsible for rotor mechanics, actuators, components and designing a space to accommodate the batteries. They design all the parts themselves. All manufacturing is outsourced. The Electronics Team who are responsible for the PCBs, which manage the power as well as the radio and satellite communication to ensure data connection to and from the LiDAR. The Embedded Software Team responsible for all the software, followed by the Simulation Control Team, who calculate the descent rate and the type of control algorithms required.
The proposed solution to address the specific goal of project Daedalus2 – a safe and controlled descent to earth – involves the use of a LightWare SF30/C LiDAR. This LiDAR was specifically chosen as a result of its sensing range of 100 metres, which allows for longer range ground detection and because of its fast update rate of up to 20 000 readings per second.
The LightWare SF30/C LiDAR is mission critical to project Daedalus2. The Daedalus2 “SpaceSeed”, once ejected, can reach speeds of up to Mach two. In this application, the Daedalus SpaceSeed will fall in a trajectory where it naturally starts to slow down to a stable glide speed. From this glide speed, energy is generated to start a spinning rotor. The LiDAR then accurately detects the distance from the ground, so that the spinning rotor is able to manage its energy and use it to slow down the SpaceSeed to zero velocity. All these calculations and activities must take place in a matter of two-to-three seconds, to prevent a catastrophic impact with the ground.
At the time of this story, the project was still in the testing phase. Official launch of Project Daedalus2 is scheduled for sometime in March 2022. We look forward to chatting with the team again to find out how the launch went! Interested in following their story? Why not follow team Daedalus2 on LinkedIn https://www.linkedin.com/company/wuespace/