SDSS
Self-Deployable Deorbiting Space Structures
SDSS
Self-Deployable Deorbiting Space Structures
Low Earth Orbit (LEO) is densely populated with thousands of satellites orbiting in an altitude from 300 to 1000 km from Earth. LEO satellites primarily addresses science, imaging, and low-bandwith telecommunication needs.
When a typical satellite is launched into LEO in an altitude of around 300 km it will survive in orbit for approximately 60 days. At 650 km it takes 25-40 years before the satellite re-enters the atmosphere and in 950km it may take as long as up to 1000 years.
The long process of deorbiting defunct spacecrafts therefore leaves a huge risk of catastrophic collisions which could cause significant damage to the infrastructure in space - or even manned space ships.
ACCELERATING DEORBITING OF DEFUNCT SPACECRAFTS
One way to accelerate the process of deorbiting a satellite after ended life-time is to increase the area of the satellite in relation to its mass. Such a change of area vs. mass can be performed by deploying large areas from the satellite. This will cause an increased drag and result in a reduction of the orbital life-time of the satellite.
In the SDSS project, the device "A self-deployable highly elastic frame" is proposed as a solution for safely deorbiting defunct spacecrafts. The SDSS device is targeted satellites orbiting in LEO where aero-dynamical effects can be utilized.
For satellites launching into orbits with an altitude above 600 km the SDSS device would among others ensure that the UN guidelines of a maximum of 25 years for a satellite in orbit after ended life-time can be met.
THE SDSS DEVICE
The Self-deployable Deorbiting Space Structures (SDSS) system is composed by a wire/frame based structure which supports a sail. The SDSS can be folded into a smaller diameter allowing for a compact storage on the satellite in either a porch or in a casing.
During launch the SDSS is locked in a folded position with a wire based locking device. The SDSS device is folded in a release tray mounted on the satellite. The release tray is spring activated and locked in the un-deployed position by a resistance/burn wire termed a locking wire. The unfolding of the SDSS device is initiated by a signal to a control unit on the satellite which burns the locking wire. The release tray is deployed thus disclosing the folded sail. This allows the SDSS sail to unfold and deploy, i.e. releasing the elastic energy stored in the folded frame structure of the sail.
The unique structure of the SDSS device ensures:
- Low weight and minimal footprint when packed, so the storage requirement in the spacecraft is minimized during spacecraft launch and operation.
- No external energy source is needed for deployment, as the frame itself automatically assures correct deployment.
- Large foot print deployed, compared to the minimal foot print of the folded configuration. Thus, SDSS provides a self-contained, simple, costeffective, and platform independent deorbiting subsystem suitable for all LEO missions.
An initial prototype of the SDSS for semi-controlled debris removal was launched in 2014. The first prototype was made for a CubeSat in collaboration with GomSpace.
MULTIDISCIPLINARY RESEARCH
The research conducted in the SDSS project is unique and requires multidisciplinary research areas such as non-linear structural analysis, electronic systems, mechanical engineering, material technology, spacecraft dynamics, and satellite mission analysis.
The project was carried out between Aalborg University, GomSpace, Airbus, and University of Surrey.
Project Facts
PROJECT NAME
Self-Deployable Deorbiting Space Structures (SDSS)
EFFECTIVE START/END DATE
November 2007 - January 2021
PROJECT PARTNERS
- Aalborg University
- GomSpace
- Airbus
- University of Surrey
AAU Space Group