PULSAR aims to develop key-technologies to enable the autonomous assembly of large structures in space. Similar to industrial applications, the assembly process relies on the usage of robotic systems, building one overall structure out of modular parts. However, the in-space assembly provides exceptional challenges necessitating innovation in fields such as free-floating manipulation and high precision assembly under the influence of uncertainties. PULSAR aims to demonstrate these technologies up to a technology readiness level (TRL) of 5-6.
Autonomous assembly of large structures in space is a key challenge to implement future missions that will necessitate structures too large to be self-deployed as a single piece. The James Webb Space Telescope has reached this limit with a mirror of 6.5-meter diameter. Next generation telescope expected by astronomers, like the High Definition Space Telescope, will therefore require new assembly technologies, in particular autonomous robots. The need for large structures in space goes beyond telescopes and concerns also solar arrays for power plants, light sails to reach outermost regions of the solar system or heat shields to land on Mars.
The main objective of PULSAR is to develop and demonstrate the technology that will allow the on-orbit precise assembly of a very large structure by an autonomous robotic system. In this context, PULSAR focuses on the assembly of the primary mirror of a space telescope with a diameter of 12 meters. In this context, three demonstrators will be developed addressing the key-challenges in this endeavour:
- dPAMT: demonstrator of Precise Assembly of Mirror Tiles
- dLSAFFE: demonstrator of Large Structure Assembly in Free Floating Environment
- dISAS: demonstrator of In-Space Assembly in Simulation
The DFKI Robotics Innovation Center is developing dLSAFFE, the demonstrator of Large Structure Assembly in Free Floating Environment. To simulate on-orbit conditions, in particular the effects of micro-gravity, the demonstration takes place underwater, i.e. in the large water basin of the Maritime Exploration Hall. For this purpose, a mock-up of the spacecraft with manipulator, suited for underwater operation, is developed. The demonstration task is the autonomous assembly of a telescope mirror consisting of modular tiles. The demonstration addresses the following major challenges:
- Autonomous manipulation in a free-floating environment;
- Limited reach of the robotic arm; to overcome this limitation the system is able to “crawl” along the assembled structure;
- Optimal attitude and orbit control systems to stay in position.
The potential impact is huge for future space applications requiring large structures and further for non-space applications like underwater robotics and Industry 4.0. Providing standard components to assemble large structures will surely ease the adoption and use of this emerging autonomous assembly technology.
PULSAR is a European project within the context of Horizon 2020 and is related to the Operational Grand 8 (OG8) of the Strategic Research Cluster “Space Robotics Technologies”. The demonstrators developed by PULSAR rely on common building blocks developed within projects of the preceding call, especially ESROCOS (OG1), InFuse (OG3), and SIROM (OG5).