12/11/2021
Small Satellites
Although the UK has long contributed to the design and development of commercial and military satellites, these satellites have been launched from locations outside of the UK. This is partly a consequence of the launch location for a satellite being a function of the orbit it is intended to enter. Satellites for use in telecommunications will usually be placed into a geo-stationary orbit (GSO), in which the satellite circles the Earth above the equator at an altitude of 35,786 km and tracks the speed of rotation of the Earth. Satellites for placement in a GSO will usually be launched from locations close to the Earth’s equator to allow the launch vehicle to benefit from the rotational speed of the Earth, which is a maximum at the equator. Communications satellites are large, heavy and expensive to develop, requiring a correspondingly large (and expensive) launch vehicle. By way of example, the Star One D2 communications satellite launched by Ariane 5 in July 2021 to provide services for Latin America has a mass of just under 6200 kg, with the Ariane 5 rocket having a mass of around 780 tonnes.
However, in recent years there has been a growth in the design, development and launch of so called “Smallsats”. As the name implies, these are satellites which are smaller in size and mass. There is no universally agreed standard as to what constitutes a Smallsat, with both 500 kg and 600 kg cited as an upper limit for the mass of a Smallsat. Smallsats encompass a number of mass categories including:
- Micro-satellites – having a mass of 10-100 kg
- Nano-satellites – having a mass of 1-10 kg
- Pico-satellites – having a mass of 0.1-1 kg
Smallsats find application in earth monitoring activities, such as observing ice cover, cloud cover and vegetation. The data collected can be useful in identifying and monitoring environmental changes related to climate change. Smallsats are likely to fulfil an increasingly important role in monitoring the effects of human activity on the environment.
Smallsats are commonly placed into a polar orbit at a far lower altitude (typically 200 to 1000 km) than is required for a GSO. In a polar orbit, a satellite orbits generally about the North and South poles of the Earth. A polar orbit allows the satellite to pass over a large area of the Earth in each orbit cycle as the Earth rotates underneath, making it ideal for earth observation tasks.
Within the sphere of Smallsats are CubeSats. These are a category of modular satellite having a standardised form factor. Each satellite is formed of a number of cube-shaped modules, each module being 10cm x 10cm x 10cm in size. The CubeSat format originates from a collaboration between California Polytechnic State University and Stanford University in 1999. CubeSats provide a low cost, low mass satellite platform ideal for demonstrating new technologies, as well as performing earth observation activities. NASA promote the development of CubeSats via their CubeSat Launch Initiative, with an emphasis on opportunities for participation by educational institutions.
Although an individual Smallsat may have reduced functionality compared to larger satellites, the following patent filing outlines the possibilities for a network of CubeSats to form the basis for a space-based communications network.
The low mass and form factor of a Smallsat allows a consequent reduction in the size, complexity and cost of launch vehicle required. The use of a polar orbit also provides opportunities for space launches from countries whose land mass is far away from the equator… such as the UK.
UK Launch Sites
Various locations in the UK have been proposed for the development of a commercial spaceport. These include the following:
- Sutherland Spaceport is a proposed commercial spaceport for launching small commercial satellites on the A’ Mhòine peninsula on the Northern coast of Scotland.
- SaxaVord Spaceport is a proposed commercial spaceport for the island of Unst in the Shetland Islands.
Both northerly locations are ideally situated for launches along a northern flightpath to allow placement of satellites into a polar orbit.
UK Launch Vehicles
The planned development of UK launch sites has been accompanied by the development of launch vehicles for use in placing commercial payloads into polar orbits. There has been a focus on increasing the sustainability of the launch vehicles and reducing the carbon footprint associated with their use. This has resulted in innovations in:
- Launch vehicles which are re-usable and less costly to manufacture
- Fuels which are more environmentally friendly
These innovations are reflected in patent applications filed in this area of technology. One example of such a filing is shown here – relating to a multi-stage rocket having a recoverable rocket stage, which employs a number of “drag enhancing elements” which can inclined relative to a cylindrical propellant tank during return to Earth of the recoverable rocket stage.
UK industry is involved in the design and development of launch vehicles suitable for the launch of Smallsats into a polar orbit. Examples include:
1. Orbex – based in Forres – are developing a launch vehicle intended for commercial satellite launches from the proposed Sutherland Spaceport for pico, nano or micro satellites. The first launch is currently proposed for late 2022. The launch vehicle is a two-stage rocket, with six engines on its first stage and a seventh engine on the second stage. Payload capacity is likely to be between 10-180 kg.
The launch vehicle is intended to be fuelled using bio-propane – a clean burning renewable fuel. Bio-propane is generated as a by-product from the production of renewal diesel.
Additive manufacturing is used to reduce the number of component parts of each engine, with 3D printing being used to fabricate each rocket engine as a single piece.
2. Skyrora – based in Edinburgh – are developing launch vehicles intended for commercial satellite launches from the UK and Northern Europe. The Skyrora XL launch vehicle is projected to have three stages, with nine engines in the first stage, a single engine in each of the second and third stages, and a payload capacity of up to 315 kg.
Skyrora have also developed a fuel – known as EcoSene® – made from conversion of plastic waste.
The Future…
With the current focus on climate change, there will be a continuing need to monitor the Earth’s climate and environment. The use of small, lightweight satellites placed in a polar orbit provide an efficient means of fulfilling this role. This also provides opportunities for the development of launch sites in new locations and of smaller, less costly launch vehicles. Further, the need to reduce any detrimental effect on the environment from space launch activities provides opportunities for innovation and the creation of new intellectual property – whether relating to the launch vehicles or their fuels/propellants.
This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.
