The offered technology provides a low weight, compactly deployable support structure suitable for large deployable apertures. It is based on a bar-linkage structure, convertible from a deployed state into a folded state and vice versa. This concept allows the construction of unit cells of scalable and modular deployable structures with double curvature. This technology provides a deployment principle for support structures that enable a flexible modular architecture for building large apertures. Every strut is coupled to two others by a revolute joint forming a closed loop. The general concept of the folding scheme of a facet is depicted hereafter:

Several cells can be connected in order to build a modular construction. The key to that feature is the kinematics of the joints between facets and modules.

Concerning civil engineering applications, the cases of domes and large deployable buildings has been studied in some detail. As an example, the figure below shows a construction in a deployed state that could be either the dome of a large circular building or a large foldable tent, depending on the cross sections and dimensions of the bars. The kinematics of the deployment are as described for the space structures, with the difference of needing a central pole during the deployment that can be removed when deployed. The resulting double layers of bars or beams, provide stiffness and strength to the construction, as well as room for isolation in between the exterior roof and the interior concentric ceiling.

Innovations and advantages:

The offered technology improves actual folding / deploying structure methods.

• The package size ratio can be optimised in order to transport the structures folded and deploy in-situ
• The mass/stiffness ratio is improved
• The deployment and folding processes are reversible
• Complex shapes can be reproduced, with positive or negative curvature
• Scalability allows to grow in size by employing conventional truss-structure principles
• Modularity allows further growth, with reduced development costs

Domain of application:

This technology could be used in civil engineering and infrastructure construction.

Description

The present invention relates to a deployable tensegrity structure. Tensegrity is a structural principle based on the use of isolated components, such as rigid bars or struts (in compression), linked together by a continuous net of cables or tendons (in tension), in such a way that the rigid bars or struts do not touch each other.

The proposed structure comprises, in the deployed state, a ring shaped support structure around a longitudinal axis which comprises:

• a first flexible tension member defining a first contour of said ring shape and a second flexible tension member defining a second contour of said ring.
• a first group of rigid compression members extending between said first and second contours ,one end of each rigid compression member of the first group being mounted on the first contour whereas the other end is not mounted on a contour and a second group of rigid compression members extending between said first and second contours, one end of each rigid compression member of the second group being mounted on the second contour whereas the other end is not mounted on a contour. These first and second groups of rigid compression members are arranged with a repetitive crossing pattern around the ring.
• a first plurality of flexible tension members linking each end of a compression member mounted on one of said contours to an end of another compression member which is not mounted on one of said contours and, a second plurality of flexible tension members linking each end of a compression member which is not mounted on a contour to an end of another compression member which is also not mounted on a contour.

The deployment can be achieved by means of spring-based actuation system, housed in the compression members. During deployment the length of the flexible tension members outside the rigid compression members decreases. Once the deployment is achieved, latching devices inside the rigid members lock the flexible members in their final position.

Innovations and advantages of the offer:

The invention proposes a tensegrity deployable structure which is light, stable and reliable, especially when its deployment is considered.

An advantage to use a tensegrity structure is to diminish the risk of failure of the deployment. In non-tensegrity structures, the joints between two rigid bars or struts raise the failure risks.

Domain of Application:

• Civil engineering
• Satellite technology systems
• Aquaculture
• Solar/Thermal energy
• Satellite ground
• Solar energy
• Photovoltaic solar
• Agriculture, foresty. fishing…
• Building construction.

Description:

The structure is aimed at being designed and constructed for large, deployable apertures that vary in size from 4 to 50 metres, whilst at the same time being able to be stored in compact and low mass containers. The design will provide high deployment process reliability, to a high level of accuracy. It is also intended to provide high stiffness and stability of the deployed support structure. In order to provide support of different instruments, the design can be deployed in either a cylindrically shaped structure, or a conically deployed one.

This structure is deployed by using an actuator configured to pull a cable across the upper and lower pantograph rods, which extends the structure outwards.

The design could be useful in quick assembly or pop-up structures, such as stands or tents.

Innovations and advantages:

• The ring can be stored in a small, low mass container and deployed to sizes up to 50m, or greater
• High deployment process reliability and accuracy, more-so than conical equivalents
• High stiffness and stability support structure
• Less complex than conical mechanical support systems as found in prior art

Commercialisation aspects:

Applications and Markets
The technology may be interested for applications such as pop up/quick assembly structures, support structures (e.g. for arrays), field hospital/disaster area structures or deployable solar arrays.

Intellectual property status
A PCT application has been filed. Looking for license agreements.

Description

Deployable antenna structures exist in various forms and mechanisms, and the current technology is a further development of an existing deployable antenna. The deployment mechanism consists of a net in which the connections are formed by struts and cables, depending on their load in the deployed state. Cables are used where elements only carry tension, while struts are required where connections may carry compressive loads. The antenna surface itself is an elastic, foldable material that can be folded to small volume but will be stretched into a smooth reflective surface after deployment, in the required antenna dish shape. The shape is produced by a tension-bearing ring, formed by the bases of a series of foldable, triangular cells of the frame connected in their corners. The remainder of the deployed structure also consists of triangular cells that collectively define the precise shape of the antenna after deployment. 

The innovative aspect of the current offer is that the entire deployment is driven by a central electrical motor, even if multiple structures are linked into a larger antenna. Conventional designs of similar deployable antennas typically involve multiple elastic elements for the deployment, In multiple locations of the structure.

Innovations and advantages

The key innovation is the central electrical deployment motor which does not need the assistance of multiple elastic elements throughout the deployable antenna. This leads to the following advantages:

• easier manufacturing
• lower cost
• lower weight
• simpler control of the deployment motion
• reduced risk of mechanical failures
• scalability of the structure into arrays of similar antennas

Domain of application

• Larger antenna dimensions than available from conventional designs
• Mobile communications satellite services, mobile broadcast services and broadband satellite services
• Radio astronomy based on very large baseline interferometry (VLBI)
• Umbrella / parasol manufacturing up to large sizes (e.g. entire terrace)

Description:

Solar panels for space applications are very expensive and many methods and technologies have been employed in an attempt to improve their efficiency by increasing the amount of light gathered by a given number of cells. One of these technologies is solar cell concentrators – essentially foil panels either side of the solar panel that are angled such that they focus more incident light onto the photovoltaic cell. However, the majority of these have significant drawbacks when used in space either in terms of performance, cost, or lifetime. 

ESA has developed a deployment and locking mechanism that fits within the frame surrounding a standard solar panel. It overcomes the performance issues caused by shrinkage which is common in the standard systems that depend on tethers to maintain alignment. 

The mechanism is designed around the concept of deploying a solid strut using counter rotating cylinders joined by a cable. The strut is attached to a cable which is then wound around two cylinders in a figure of eight manner. When the central cylinder rotates anti-clockwise it induces a clockwise motion in the right-hand cylinder which in turn allows the strut to move out. Once the strut reaches the end of its travel it then becomes lodged between the left and centre cylinders.  (the strut with the dashed edge has only been shortened for drawing clarity – in the actual system it remains the same length.

Figures 1-4 below show the deployment:

For added rigidity in systems and structures that require it, tethers can be attached to the far end of the strut from additional cylinders (see Figure 5).

The mechanism is replicated on the opposite ends of the cylinders and a reflective foil is spread between the two struts. Prior to deployment this is wrapped around the centre (orange) cylinder. Depending on the exact application an appropriate insulation layer can be added as a backing to the foil. This prevents warping of the foil due to the temperature differential between the two sides.

Innovations and advantages:

• Reduced overall system cost
  • More power per solar panel
  • Reduced weight
• Reduces dependency on tethers that can contract/expand
• Fits within frame of standard solar panel
• Can easily accommodate different thermal insulation layers
• The manner in which the strut finishes its journey result in low latching shocks.

Domain of application:

• Telecommunications Satellites
  • Large arrays of solar panels could be supplemented or partially substituted
• Small sats/cube sats
  • Improve energy harvest whilst maintaining low weight and cost
• Terrestrial Applications
  • Compact, deployable structures for advertising/exhibition stands

Description:

The peculiarities of space make the bearing choice in spacecraft difficult. Commonly encountered requirements are a maintenance-free operation for more than a decade, the tolerance against the degradation of fluid lubricants due to outgassing, radiation and other effects, the need for low friction caused by limited electrical power, and robustness against the high loads that the bearing has to sustain during the launch of the spacecraft.

State-of-the-art Reaction Wheel technology is mainly based on rolling element bearings, which have a number of disadvantages:

• The tribological contact between ball, raceways and cage requires constant lubrication.
• The small contact area between raceways and rolling elements leads to high Hertzian contact pressures. Ball bearings are consequently sensitive to overload conditions which could deform either the rolling elements or the raceways.
• Ball bearings provide little mechanical damping through their direct ceramic-to-metal or metal-to-metal contact, transmitting (unwanted) mechanical vibrations.
• Manufacturing tolerances of rolling element bearings cause unwanted mechanical vibration and noise.
• The lubrication function of the liquid lubricant is only guaranteed above a threshold speed of approximately 200 rpm.

 To overcome those disadvantages, this gas bearing system is presented. Figure 1 illustrates the elements of the invention, which consists of a combination of: 

1. A static gas bearing.
2. An ultrasonic pump (located inside the sealed compartment) as gas supply.
3. A hermetically sealed compartment.
   For operation in the vacuum conditions of space, a hermetically sealed housing is required to maintain the working gas present throughout the lifetime of the spacecraft. Potential gas leakage can be avoided by reducing the number of flanges and parts to an absolute minimum. In any case, a sealed access lid is required to allow the assembly and repair of components inside the housing.
4. A low pressure, low viscosity gas inside the compartment, to minimize areodynamic losses.
   A reduction in gas pressure will not only reduce aerodynamic losses, but also reduce the absolute pressure at the pump inlet.

Innovations and advantages:

• No fluid lubrication is required, avoiding any problem stemming from lubricants such as lubricant loss, evaporation, degradation, creep.
• Excellent dynamic behaviour.
• The vibration and noise emission of the gas bearing Reaction Wheel is 10x – 100x lower than the emission of a ball bearing Reaction Wheel.
• Friction torque noise is absent in gas bearings, leading to a better spacecraft pointing stability.
• Allow the reaction wheel to operate at higher speeds than +/- 200 rpm while maintaining good stability and performance.
• Practically unlimited lifetime due to the absence of physical rotor-stator contact.
• Considerably simpler to build than Magnetic Bearing Reaction Wheels as the part count is lower, the manufacturing requires standard tools and processes and the assembly process can be automated.
• The electronics for the micropump are considerably simpler than the one for a Magnetic Bearing Reaction Wheel.
• Cheaper and lighter than Magnetic Bearing Reaction Wheels.

Domain of application:

For many mission types the reduction of microvibration is a key aspect to achieve mission objectives. This includes various Earth observation, Science and (optical) telecommunication missions, i.e. missions with stringent fine pointing requirements. 

A gas bearing type reaction wheel, if successfully qualified, would be a very attractive solution, since it would be less bulky, less complex, but more performant than current concepts. 

Further, the combination of a vibrationless micropump and a static gas bearing could be interesting in the field of precision engineering, specifically in applications where the supply of pressurized gas for gas bearings is difficult to achieve. These could be autonomous sliders or bearings on flat floors etc.