Support for a more connected world

With the growth of communication technologies and an ever-increasing need for a more connected world, satellites have become a crucial part of our infrastructure.

Currently there are 9,494 active satellites in various earth orbits, with more than half of these for communication (telecommunication, broadcasting & data communications) uses.

In the last 3 years the trend has become the launch of constellations of satellites, as the chart below shows – there has been a dramatic increase in the last 3 years, with growth also expected during 2024.

COTS in Space

The use of “Commercial Off The Shelf” components being used in space applications has become a hot topic in the industry in the last few years. This indicates a big shift for NASA, historically the Space industry has carried out detailed parts qualification and screening process using components inside the MIL-SPEC parameters.

NASA commissioned a study in 2020 to evaluate the use of COTS devices, this study was required to prove that the use of COTS devices would be as reliable as possible. Part of this requirement was driven by the need to stay competitive and meet the ever-growing requirement for satellites.

Many satellite companies are launching into Low Earth Orbit (LEO) rather than Geostationary (GEO) satellites, the coverage the LEO satellites supply is lower than the GEO satellites. This makes costs a genuine consideration more satellites are required to match the coverage of the MEO ?and GEO satellites. This has also played into the need for COTS devices usage to aim to reduce costs and lead times.

The allowance of COTS in space has undoubtedly increased the growth of commercial satellite companies and grown the industry worldwide.

But….. it does come with an issue; the use of Tin (Sn) Zinc (Zn) and Cadmium (Cd) is prohibited on hardware in Space. The vacuum of space is a “welcoming” environment for the growth of tin whiskers meaning the potential for failures due to a new conductive pathway forming leading to shorting issues.

COTS devices can have a pure tin or part tin finishes, which leaves companies designing and manufacturing PCBs for space application with a dilemma with sourcing issues to find the correct components with low to zero tin content. This then takes them back to the days of having to source approved MIL-SPEC devices and means they are having to wait increased lead times and face increased costs in some cases.

There is a solution for this that Retronix offer and that is to alloy convert your components. Converting to Pb is a time tested and proven solution for eliminating the risk of tin whiskers that Retronix has been carrying out for customers since the start of the ROHS directive in 2006.

Historically the customer base of Retronix for this service has been Mil/Aero, but over the course of the last 2 years we have seen a significant growth in demand for this service from the Space Sector and have recently been involved in a project to alloy convert 100% of a customers Bill of Material for multiple PCBs used in a recent satellite constellation launch.

Companies have previously selected certain components for alloy conversion that the customer has deemed most at risk. This still exposes the customer to risk of tin whiskers on components that have not been through alloy conversion. Most commonly this tends to apply to micro devices – 0402, 0603, 0805 etc. These are often not alloy converted as the belief is the soldering of ROHS devices using Pb solder will mitigate the risk. But trials have proven that soldering of these devices using Pb solder still leaves a ROHS solder area on the top surface of the termination as the Pb solder will flow up the front and side edges, but will not always cover the top surface termination. Image below shows this example.

This process, while minimising the risk of tin whiskers does not eliminate it as you still have a one of the five surfaces of the component termination with ROHS solder and Tin coverage.

With the component population of micro devices on PCBs becoming closer in location (as the above right hand picture shows) the growth of tin whiskers between two components is a real risk when design rules allow gaps between 0402 devices to be as small as 0.17mm in the X direction and 0.13mm in the Y direction.

The Retronix Solution

With the automated process designed exclusively by Retronix for tinning micro components including 0402, 0603, 0805 & SOTs to GEIA Standard, the industry now has a solution for alloy converting these devices.

In many cases, the approach to micro device tinning has been “No suitable process that meets GEIA standards exists” Now Retronix offer an automated solution that does solve this industry problem.

For more information about this service:

See link - Tin Whiskers - Space Industry 2024 (retronix.com)

Or contact – [email protected]