Space
Selecting connectors for CubeSats
By Giorgio Potenza, head of business development EMEA, Harwin
an effective way of undertaking space ventures, with potential for research institutes, universities and schools to get involved. Their compact size makes them far more cost- effective to build and deploy than larger conventional satellites. This format has proved so popular that in 2020 approximately 450 were launched.
C
One CubeSat unit (or U) has a volume of 10cm x 10cm x 10cm and using this standard size format, they are constructed in stacks that are 1U, 2U, 3U, etc. Compared to other types of space hardware, these much smaller dimensions result in the ability to carry many more satellites into space as rocket payloads.
ubeSats first started to appear almost twenty years ago, and since then have become a popular way for scientists to access space. These compact satellites represent
What this means is the constituent PCBs will be very tightly packed together. That, in turn, presents engineering challenges for interconnect designs.
Given the challenging and
uncompromising environment of space, electronic equipment must endure the rigors of the launch and de-tumble process, and also work reliably for the long term. Even the smallest component failure could jeopardise the whole mission, resulting in valuable lost space operation time and the high cost of launching a replacement.
Key characteristics when specifying interconnects for CubeSats
Here are the most important attributes required for the design of reliable and effective connectors and cable assemblies: 1. Resilience to mechanical stresses – The connectors/cabling must withstand the harsh conditions associated with space deployment. These will be at their highest intensity during launch. At this point, the hardware will experience heavy vibrations and high levels of acceleration.
2. Extreme temperature variations – CubeSats face extreme temperature cycling during each rotation around the Earth. The connectors used must be robust enough to cope with severe cold when passing the dark side of the Earth and likewise the intense heat of direct thermal radiation from the Sun.
A 1.25mm pitch Harwin Gecko connector with braided cabling.
18 October 2021
3. Space constraints – By definition, CubeSats must be incredibly compact, with even the
Components in Electronics
Harwin Gecko connectors implemented into a 1U CubeSat design. [Courtesy of Warwick University]
larger 12U size only 20cm x 20cm x 30cm dimensions. Connectors intended for these designs must take the absolute minimum of available board space, ensuring enough room is left for all other parts. Also, since a CubeSat’s PCBs are placed closely together, low profile connectors are essential.
4. Weight constraints - given the high cost to launch satellites, the lower their weight, the more economical they are. This approach can also free-up weight for additional payload.
5. Outgassing – The vacuum of space causes outgassing, involving the release of gases and molecular particle debris contained within plastics. Once the CubeSat is in orbit, any of these gases or particles could affect the operation of sensitive devices leading to failures.
Sourcing space-optimised interconnect solutions Harwin’s 1.25mm pitch Gecko connectors are designed into many CubeSats currently in orbit. It has space-saving footprints and low profiles, superior outgassing properties, plus a lightweight and extremely rugged design. With the ability to withstand sudden 100G shocks and temperatures of up to 125°C, it makes these interconnects perfectly optimised for this kind of application. Gecko’s 2A rated Beryllium Copper contacts have a proprietary 4-finger design. As a result, there is always a connection with one of the corresponding mating surfaces, which ensures that Gecko connectors provide exceptional resilience to vibrations (being
tested at 20G for 6 hours). Advanced screw- based locking mechanisms are another important design feature, these maintain continued interconnect integrity even when subjected to strong pulling forces. Gecko connectors are available in right- angle configurations. This allows them to be positioned on board edges, instead of towards the centre. This means that less headroom is used which is often an advantage, especially given that there are only relatively small gaps in between CubeSat PCBs.
As the cabling attached to these horizontal connectors can be placed on the outside of the CubeSat framework, the entire interconnect system is easier to access during the build phase. Thanks to benefits like this, cables are not affected by acute bending, so the operational reliability is higher than centrally located connectors. Complementing its Gecko range, Harwin’s off-the-shelf cable assemblies come in a variety of predefined lengths.
Conclusion
When specifying connectors and cabling for use in space applications, there are many important considerations. Overlooking any of these has the potential to cause mission failure. But by understanding each of the key points covered in this guide, you’ll find solutions that will help you successfully meet the unique requirements of engineering connectors for space and for CubeSat designs.
www.harwin.com
www.cieonline.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54
