FEATURE ELECTRONICS FOR HARSH ENVIRONMENTS


Linking to the stars High Contact Density Connectors for


Nanosatellite-Based Communication Networks Words by Giorgio Potenza, strategic market manager, avionics, defence and space, Harwin T


hough most of us now live in the ‘Connected Age’, it must be conceded


that not everyone is quite so lucky. There are still certain areas of the planet which are simply too sparsely inhabited for it to be economically viable to roll-out a terrestrially-oriented communication infrastructure. As a result, much of the Earth’s population hasn’t experienced the benefits of the next generation of voice/data services that are already commonplace elsewhere. Australian communications provider


Sky and Space Global is looking to change this, planning to offer services through the implementation of its latest nanosatellite constellation. Referred to as ‘The Pearls’, this will comprise around 200 nanosatellites – located in low Earth orbit (LEO) above the Earth’s surface – in orbital rings near the equator. The objective of this arrangement is to provide more cost- effective communication capabilities to underserved parts of the world. The multitude of nanosatellites that make up ‘The Pearls’ constellation are all fitted with 3m of sun-tracking photovoltaic panels, through which solar energy can be acquired. Each one will be positioned in orbit, evenly spaced from other nanosatellites, creating an orbital ‘necklace’. With communications frequencies residing in the S band (2GHz to 4GHz), they will also have the capacity to communicate with one another. It will take each of the nanosatellites approximately 90 minutes to circle the globe. As they continue through their orbit, they will hand over communication coverage of an area to the next nanosatellite in the chain, subsequently taking on coverage from the preceding nanosatellite. By forming an unbroken ring of nanosatellites in this way, the narrowband wireless coverage will be maintained. Via this ambitious venture, it will be possible for voice, messaging, IoT and M2M communication services to be made available cost-effectively. It follows on


36 OCTOBER 2019 | ELECTRONICS


from the success of the company’s ‘Three Diamonds’ constellation, which was launched into space back in mid-2017. Consisting of just three nanosatellites, this mission was established to test the feasibility of all the building blocks of the larger scale project, validating


he larger scale project, validating that both the coverage delivery and the hand over functions could be accomplished simultaneously and of course, effectively.


In order to minimise both the launch payload and


ongoing power consumption, each of these nanosatellites will have a diminutive form factor,


“Given that there is such limited space to play with, it is of paramount importance that we can utilise compact, low-profile components”


with external dimensions of no more than 24cm x 45cm x 12cm. This means that the essential electronic circuitry must be squeezed into a confined space. It has been critical that the


with external dimensions of no more han 24cm x 45cm x 12cm. This means


nanosatellite design should feature commercial off-the-shelf (COTS)


components, rather than rely on the use of custom products. Sticking to this tactic has not only helped to avoid accruing hefty upfront costs, but has also resulted in ease of development and manufacture. With the project already underway, Harwin began to engage directly with GomSpace, with the companies’ respective engineering teams entering into in-depth discussions on how to best deal with all of the connectivity considerations. Based on their compact size, lightweight plastic-shelled


construction and ruggedness, various members of Harwin’s Gecko latched connector series would be specified. These high contact density, narrow pitch (1.25mm) connectors have been employed in a host of space-related projects in recent years. Being resistant to shock and vibration, as well as having an operational temperature range that spans from -65 to


employed in a host of space-related projects in recent years. Being resistant to shock and vibration, as well as having an operational temperature range that spans from -65 to +150 degrees Celsius.


the Gecko product series is its outgassing properties. These connectors perform well when placed into a vacuum, thereby safeguarding against a potential cause of faults in electronic circuitry. An initial quantity of 100 units was


Another key advantage of the Gecko product series is its outgassing properties. These


placed into a vacuum, thereby safeguarding against a potential cause of faults in electronic circuitry. An initial quantity of 100 units was


supplied for development. This was made up of both through-hole and surface mount versions (in 6-pin to 34-pin formats), with more than 35 mated pairs being incorporated into every nanosatellite.


“For each nanosatellite, we have


numerous, heavily populated boards that must be stacked closely together, with little headroom between them. Given that there is such limited space to play with, it is of paramount importance that we can utilise compact, low-profile components that contribute very little to the overall weight of the system. These need to simultaneously exhibit high degrees of operational robustness to deal with the uncompromising nature of the application and also come at an acceptable price point, so that budgetary problems are avoided,” explains Klaus Ahlbech, research and development director at GomSpace: “Harwin’s Gecko connectors have shown that they have all the characteristics mandated by this project, providing us with assured, long- term inter-board connectivity, even in these challenging circumstances.”


Harwin www.harwin.com / ELECTRONICS


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