The antenna unfolds almost like an umbrella. Image source: OSS
An innovative, affordable radar satellite that will be launched by two British businesses will include parts knitted on a knitting machine.
In order to close a gap in the nation’s eavesdropping capabilities, the UK would launch a new satellite mission named CarbSar the following year.
The satellite will operate at night and employ radar technology to look through clouds.
To keep track of Russian locations throughout the crisis in Ukraine, this technique has proven invaluable.
The mission is considered as a chance to develop a domestic capability for Britain, the only permanent member of the UN Security Council without a system.
The spacecraft will be built by Surrey Satellite Technology Limited and Oxford Space Systems, with funding from the government and a confirmed launch on an American rocket.
SSTL has built a solid reputation in aerospace manufacturing, but their latest innovation lies in the OSS radar antenna.
This groundbreaking technology uses a tightly folded tungsten wire mesh that unfurls upon deployment to create a large, umbrella-like shape.
With a diameter of 3 meters, this antenna/reflector will allow the satellite to capture high-resolution images of the Earth’s surface.
SSTL and OSS have developed the CarbSar pathfinder to showcase the capabilities of this new technology.
By demonstrating its effectiveness, they hope to secure future contracts for operational spacecraft from the UK government for both military and civil applications.
The government has invested in this promising technology through the National Security Strategic Investment Fund, which aims to support technologies that have potential for national security and defense purposes.
The success of the knitted satellites will be of great interest to the government as they explore the possibilities of this innovative technology.
Government defense R&D has backed the satellite idea. Image source: SSTL
The CarbSar project will involve a partnership between SSTL and OSS, with each company contributing their unique expertise.
While SSTL will be responsible for building most of the satellite’s internal systems, including the electronics that operate the radar, OSS will provide the deployable antenna/reflector.
A prototype of this innovative “wrapped rib” design is currently undergoing testing at OSS’s Harwell headquarters.
The structure comprises a gold-plated tungsten mesh that is attached to a series of carbon-composite rods.
These rods can be wound radially against a central hub, allowing the antenna to be compacted for launch.
Upon release, the rods will naturally spring back to their straightened configuration, creating the tension needed to pull the mesh into position and form the antenna.
This mechanism is similar to the way a builder’s tape measure snaps longways when unrolled.
The resulting 3m-wide antenna/reflector will enable CarbSar to capture high-quality images of the Earth’s surface, demonstrating the potential of this new technology for future space missions.
For the mesh to provide the desired performance, it must be constructed to strict specifications. Image source: OSS
OSS has built up a sizable rig at its plant where it can repeatedly test the stowage and deployment of the structure in order to assure the successful deployment of the CarbSar antenna.
The antenna’s deployment mechanism must be as straightforward and reliable as possible, hence this testing method is essential.
Sean Sutcliffe, CEO of OSS, believes that keeping things simple will help to reduce the likelihood of failure.
The antenna will be strong and able to survive the pressures of launch and deployment in orbit according to the company’s stringent testing methods.
Sutcliffe emphasizes the importance of ensuring that the antenna deploys fully and reliably, without the risk of stalling or damaging the satellite.
This requires balancing the antenna’s strain energy to achieve optimal performance without over-stressing the system.
The mesh itself is a remarkable feat of engineering, as is the process used to manufacture it.
The yarn used for the mesh is incredibly fine, almost invisible to the naked eye.
Reels of this specialized yarn are fed into an industrial knitting machine at the OSS factory, which is operated by a former fashion lecturer from Denmark.
Knitting machines are unusual to find at satellite factories. Image source: OSS
The machine knits the yarn into a tightly woven, gold-plated tungsten mesh that is both strong and lightweight.
This innovative manufacturing process allows the mesh to be produced with the precision and consistency required for high-performance aerospace applications.
Achieving precision is crucial for the success of the CarbSar project.
When the mesh is deployed, it must conform to exacting standards to ensure that it forms a parabolic shape with minimal deviation.
OSS’s business development director, Michael Lawrence, explains that the company uses a laser scanner to check the mesh before and after deployment.
The scanner ensures that the mesh conforms to the required shape, with deviations of less than a millimetre.
The UK has been discussing the possibility of launching a network of radar satellites for some time.
The Ministry of Defence has been allocated funding to procure these satellites, with the aim of enhancing national security and defence capabilities.
The success of the CarbSar project could put SSTL and OSS in a strong position to win future contracts for operational spacecraft, further strengthening the UK’s space industry.
The CarbSar satellite’s radar sensing capability has a wide range of potential civil applications in addition to military and defense uses.
The satellite might be used, for instance, to track the volume of flooding or spot signs of subsidence and landslides.
The benefit of employing radar imaging is that it can provide images regardless of the current weather, ensuring that emergency responders and decision-makers have access to a steady stream of data.
SSTL had launched its own radar satellite in 2018, but it is anticipated that the CarbSar variant will be more popular.
Its better resolution, which enables it to identify things less than a metre wide, is one important advantage.
The potential of the CarbSar project is further demonstrated by the level of accuracy and detail that may be particularly useful for both civil and military uses.