The mission will comprise of a main satellite platform (~100kg) that once in orbit will deploy two CubeSats as artificial debris targets to demonstrate some of the technologies (net capture, harpoon capture, vision-based navigation, dragsail de-orbitation). The project is co-funded by the European Commission and the project partners, and is led by the Surrey Space Centre (SSC), University of Surrey, UK. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 607099.
The academic team that has worked at this project delivery includes Prof G. Aglietti, Prof. C Underwood, and Dr C. Bridges, and the Remove Debris consortium from Jan 2016 has been led by: Mr Simon Fellowes. Main contact: Prof. Guglielmo Aglietti, Project Principal Investigator, firstname.lastname@example.org.
The RemoveDEBRIS platform will be launched to the International Space Station (ISS) using a NanoRacks service and Space X rocket in 2018. The sequence of launch is described as follows. The platform is packed in specialist boxes which are launched to the ISS. The boxes are unpacked by the astronauts and installed on a slide table. The slide table moves into the ISS Japanese module and a special robotic arm grapples the platform and moves it outside the ISS. The arm then releases the platform in a very specific direction and the mission begins.
The sequence in which the experiments are undertaken is shown below. After launch, and deployment from the International Space Station, ISS (see the launch page), the 4 experiments are undertaken.
Net Experiment + CubeSat
The net experiment is shown as follows. The experiment is designed to help mature net capture technology in space. In this experiment, initially the first CubeSat (produced by Surrey Space Centre), DS-1, is ejected by the platform at a low velocity. DS-1 proceeds to inflate a balloon which, as well as acting as a deorbiting technology, provides a larger target area. A net (produced by Airbus DS) is then ejected from the platform when DS-1 is at 7 m distance. Once the net hits the target, deployment masses at the end of the net wrap around and entangle the target and motor driven winches reel in the neck of the net preventing re-opening of the net. The CubeSat is then left to deorbit at an accelerated rate due to the large surface area of the balloon. During the net demonstration, two supervision cameras record images which are downloaded afterwards to ground to assess the success of the net demonstration.
VBN (Vision-Based Navigation) Experiment + CubeSat
The vision-based navigation (VBN) experiment is shown as follows. In this experiment, the second CubeSat (produced by Surrey Space Centre), DS-2, is ejected by the platform at very low velocity. The VBN camera and Lidar (produced between Airbus DS, CSEM and Inria) then collect data and send it via the platform back to the ground for processing.
Airbus DS has been strongly involved in the design of systems over the last years, with particular focus on applications such as planetary landing and orbital rendezvous, typically in the context of Mars Sample Return missions. Based on this background and due to the increasing interest in Active Debris Removal (ADR), solutions for autonomous, vision-based navigation for non-cooperative rendezvous have been investigated. Dedicated image processing and navigation algorithms have been designed at Airbus Defence and Space and INRIA to meet this specific case, and some of them have already been tested over synthetic images and actual pictures of various spacecraft. As the next step, the VBN demonstration on-board RemoveDEBRIS will validate vision-based navigation equipment and algorithms, through ground-based processing of actual images acquired in flight, in conditions fully representative of ADR.
Images will be captured from two main optical sensors: a conventional 2D camera (passive imager) and an innovative flash imaging LiDAR (active imager), developed by the Swiss Center for Electronics and Microsystems (CSEM). It will be a scaled-down version of a 3D imaging device currently developed and tested in the frame of “Fosternav” FP7 project for the European Commission focusing on landing and rendezvous applications. All the data acquired during the VBN experiment will be processed on the ground with innovative algorithms.
VBN Equipment (Camera and Lidar)
Intelligent Algorithms Performing Image Processing
Harpoon + Deployable Target
The harpoon and deployable target experiment (undertaken by Airbus DS) is shown as follows. In this experiment, a deployable target extends outwards from the platform which is used as a target for the harpoon. The harpoon and the deployable target form the harpoon target assembly (HTA). The distance for harpoon firing is 1:5 m on a 10 x 10 cm target. The harpoon is designed with a flip-out locking mechanism that prevents the tether from pulling out of the target. As for net and harpoon demonstrations, success will be assessed by the images collected by the 2 supervision cameras.
Harpoon + Deployable Target Experiment
Harpoon Target Assembly (HTA)
The RemoveDEBRIS platform will have a dragsail payload (produced by Surrey Space Centre). The function of the dragsail is to, when deployed, to allow the satellite to de-orbit quicker, and to burn up faster in the Earth’s atmosphere much quicker than if the dragsail were not deployed.
The dragsail consists of 2 parts: an inflatable deployer which extends the sail away from the platform (preventing the sail from hitting any overhanging platform hardware e.g. antennas), and an extension mechanism which uses a motor to unfurl carbon fibre booms that hold the sail membrane. The deployer is an inflatable mechanism that deploys to a length of 1 m and self-hardens. The extension mechanism consists of four booms rolled into a central distributor that allows controlled unfurling of the sail.
Dragsail Extension Mechanism
The RemoveDebris platform is provided by SSTL and utilises the next generation of low earth orbit spacecraft avionics systems and structural design being developed at SSTL called the X50 series. The X50 architecture is based on a modular and expandable philosophy that utilises common modules. This allows the system to be adaptable to varying mission applications and requirements.
The platform is based on four side panels, a payload panel, and a separation panel. Payloads are mounted either on the payload panel within the payload volume atop the avionics bay or along the side panels as required.