The challenges – and opportunities – of space engineering in the 2020s and beyond

Q. Laser and optical technologies are starting to replace radio-frequency (RF) for space communications. Why is this – and are there implications for other space disciplines such as Earth observation, defense, and space exploration?

Laser and optical communications deliver many, many advantages over RF in space. Firstly, they offer much higher bandwidth, meaning they can carry more data. To put it in everyday terms, it’s like the difference between having your phone or internet signal brought to your home through slow copper wire, or through beefy fiber optics.

Secondly, laser light propagates in a narrower beam than RF – it delivers precise, focused, point-to-point communication, and a lot more of it hits the target for much lower power consumption, which means less loss and, ultimately, communications satellites that are smaller and lighter.

It is these satellites that are principally driving the evolution from RF to laser and optics. I think Earth observation, space exploration, and space defense applications will certainly benefit from this transition over time, but the immediate hotbed of laser and optical communications links in space is communications satellites. This is because it’s where the commercial opportunity lies – in particular, in the Low Earth Orbit (LEO) sector.

Q. You mention LEO satellites, and these are now a huge focus for many satellite companies. Why all the hype – and what are the hurdles?

LEO is massive right now for telecoms applications. The approach depends on having many orbiting satellites that all communicate with each other in an interconnected network, or “constellation”. These satellites orbit the planet quickly, close to its surface, at heights usually less than 1000 kilometers. Though this might seem a huge distance, it’s much lower than conventional geostationary telecoms orbit (GEO) satellites that stay in the same place relative to the Earth.

LEO networks potentially offer a number of benefits over GEO satellites, including reduced latency and lower link losses, which means faster and more reliable communications. To provide extensive coverage and handle the huge quantities of data plan, constellations of very many satellites are required, as opposed to the one-off, hugely expensive telecoms satellites used in GEO.

The big players are therefore looking to produce and launch literally thousands of LEO satellites – but for that to happen, the cost needs to come down dramatically.

Q. How is that feasible?

One way it becomes feasible is by building satellites using components that come from highly vertically integrated environments – where raw materials manufacture, production, and testing all happen, and are considered holistically. These environments can deliver extremely high levels of reliability and at low cost, but there needs to be tight control over both efficiency and quality every step of the way.

It is about understanding what to incorporate in manufacturing, and how, and what not to, as well as the difference between rigorous testing and over-testing. It’s an approach that requires skill and expertise across a broad mix of disciplines. A solid engineering heritage also helps ensure there are very few surprises.

Q. What technologies are required to deliver optical communications links in space?

There are a large number of technologies that are required to produce optical links through space, and many entities are racing to produce them. One key element is high-power optical amplification modules, which are required to overcome transmission losses between satellites that are thousands of kilometers apart.

G&H is at the forefront of this work and produced the first commercial optical amplifier to be used in geostationary orbit. Working with the European Space Agency (ESA) on project EPOS (Extremely Powerful Optical Sources), we continue to drive innovation in the sector.

Developing high-power amplification of this kind tends to automatically mean that the development of lower-powered variants also accelerates and improves, so there are potential benefits across many other applications.

Q. Space is a tough environment – what about the challenges this presents to precise engineering components, as ever more of them find their way up there?

Space is indeed a very unforgiving environment for engineering components. You have extreme vibration, shock, temperature variations, radiation, and outgassing. Then consider that the components in question must be totally reliable – because space is a long way to go to fix something – and it can seem like a big ask. This all adds up to there being many ways that even the best terrestrial component that hasn’t been specifically designed or adapted for the purpose can fail.

Vertical integration, a deep technical understanding and a solid engineering heritage enables selection of the right components, and provides the know-how to modify them so they can be used in space – using hermetic packaging and high-reliability (Hi-Rel) materials, for instance.

This is only part of the challenge, however. The integration of the components must also be well understood; badly designed housings can amplify thermal and vibrational problems, for example, and offer insufficient protection against radiation. Finite element modelling is a key tool that enables these challenges to be assessed early.

Q. Is it possible to produce complex space engineering technologies in smaller, lighter, more energy-efficient and cost-effective forms?

As well as requiring cost effective and reliable designs, solutions for space often require reduction in size, weight (mass), and power consumption (SWaP). However, reductions in size and mass are difficult, as they often work against the development of tough designs that can withstand the harsh environment of a rocket launch then operation in a space environment.

One has to make every gram of weight and milliliter of volume in a design count, and large reductions in size and weight are the product of an innumerable number of marginal gains – much like a high-performance athlete.

Power consumption is king, and reducing it aids almost every element of the design. Like reductions in size and weight, there is no one silver bullet that enables low power operation, and improvements are hard-won. The system must be considered holistically, with an understanding of many disciplines and in deep detail at an individual component level. Again, this very much comes back to highly vertically integrated manufacturing expertise.

This vertical integration also enables tight control on both quality and efficiency, ensuring that nothing is there that shouldn’t be – which speaks to the size and weight point – and that everything that is there gives the best possible performance, which addresses the power and efficiency angle.

Q. What would be your advice to manufacturing partners and OEMs looking to supply the space industry to meet its next generation of challenges?

For me, it’s about making sure they choose a solid engineering partner with proven space expertise and heritage, because space engineering has plenty of pitfalls that lay in wait for the inexperienced.

As I said before, we’re on the cusp of a massive satellite communications revolution with LEO, and the demand it generates will require volume production of exceptionally exacting fiber optic components, at great speed, and at maximum cost-effectiveness. To pull that off, you need experts across the piece, rigor at every stage, and a supply chain under one roof.