Space
The value of microsatellites and the component technology behind them
By Ben Green, Harwin M
icrosatellites now perform a wide variety of Earth observation and environment monitoring tasks and are used to conduct numerous
scientific experiments. Over the last decade, this technology’s emergence on the space scene has reduced the costs involved in satellite development, leading to accelerated deployment into orbit; compared to more conventional satellites. From a commercial point of view, they are at least an order of magnitude less expensive, causing significant disruption in the space sector and encouraging new entrants to participate. It must be noted, though, that the resource-constrained nature of microsatellites and the often challenging application environments where they operate present engineers with unique design challenges. Microsatellites have succeeded in altering the dynamics that influence space projects. In simple terms, they have meant that: ● Projects which would not previously have been commercially viable can now be taken on.
● Organisations which would not have had the budget needed before can now participate in space ventures.
● On top of the cost advantages, project completion is much quicker.
● CubeSats have become the go-to format for many so-called ‘New Space’ projects. These compact units are highly suited to low-Earth orbit (LEO) deployment. Over 2000 of them have been launched to date, with several hundred currently going into space each year.
Sourcing the correct components Appropriate component selection for CubeSats is affected by the following factors: ● A CubeSat can have dimensions of just 10cm3 (1U), meaning there is little room to fit all the necessary hardware. For this reason, the most compact components always need to be chosen.
● Similarly, to keep within stringent rocket payload restrictions, CubeSats cannot be too heavy – so lightweight components must be used.
18 October 2022 Figure 1: A CubeSat constellation in orbit [Courtesy of Gomspace]
● CubeSat hardware will experience heavy shocks and vibrations during launch. It will also be exposed to extreme temperature cycling when passing from being shaded by the Earth into direct sunlight (and back again), meaning robust, ultra-reliable components are essential.
● Limited budgets generally mean that cost-effective commercial off-the-shelf (COTS) components must be used instead of more expensive custom-designed ones. Nevertheless, these components must be rugged enough to function in space for an acceptable period of time.
● The vacuum of space can also lead to outgassing, where substances are given off from
components that could impact the
functions of other electronic devices in the CubeSat. For this reason, parts with superior outgassing properties should be chosen.
Components in Electronics
● LEO deployment means CubeSats are subject to greater radiation levels than higher orbits.
For connectors, in particular, there are other considerations to include. For example, because space-deployed hardware cannot easily be repaired once in orbit, every engineering effort must be made to prevent connection failures within mission-critical systems. Also, to save space, it will often be advisable to use connectors capable of simultaneously carrying power and data signals (rather than needing separate components for each).
Recent case studies
Addressing the criteria just outlined, Harwin offers high-reliability (Hi-Rel) interconnect solutions that are highly optimised for space deployment.
Here are a few case study examples highlighting their value in space-related projects: Nordic satellite company
Figure 2: Example of a 3U CubeSat [Courtesy of University of Warwick]
Figure 3: Harwin Gecko series various cabling options
is assured, even when 50G shocks and 20G vibrations are applied.
Rome-based company GAUSS uses Harwin interconnects in its UNISAT cost-optimised microsatellite ridesharing service. Here, 2mm-pitch Datamate and Datamate Mix-Tek connectors are incorporated into nearly all the subsystems of the UNISAT spacecraft – enabling power and data.
https://www.harwin.com/
www.cieonline.co.uk
Gomspace engaged with Harwin on its ‘The Pearls’ microsatellite constellation venture, which is now helping to bring broadband communication to developing economic regions. Each of these microsatellites has 24cm x 45cm x 12cm dimensions. Harwin’s low-profile 1.25mm pitch Gecko connectors were selected for the design. The contacts are embedded into a plastic material to keep the weight down, but the construction of these connectors is still rugged enough to deal with tough operating conditions. For instance, they can withstand temperatures up to +150°C. The Gecko series also proved its worth when an academic research team at the University of Warwick looked at using CubeSats to monitor wildlife movements. Crucial to the WUSAT-3 mission was continued operational reliability. As Gecko contacts have a proprietary 4-finger arrangement, ongoing interconnect integrity
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