Almost 60 years after the first satellite was launched, space is becoming ever more cluttered with defunct satellites, spent rocket boosters and sundry stray pieces.

To help deal with the problem, UK filter and capacitor manufacturer MPE recently produced and supplied a suite of custom high-current EMC protection filters for applications in the US Air Force’s new Space Fence facility, which became operational in March 2020 on Kwajalein Atoll in the Marshall Islands.

The Space Fence is a system of second-generation, S-band ground-based space radars built by prime contractor Lockheed Martin for the USAF, in order to track the increasing amount of space debris and artificial satellites in low Earth orbit (LEO) and avoid potential collisions.

The workings of the technology are explained in more detail in this program overview on YouTube:

Travelling at speeds upwards of 15,000 mph, space debris threatens not only commercial satellites, which we depend on for everything from weather forecasting, banking, global communications and GPS navigation, but also military satellite communications critical for national security.

Richard F Ambrose, Executive Vice-President of Lockheed Martin Space Systems, summarises: “Ground-based situational awareness is a growing priority for government and commercial organisations around the world who need to protect their investments in space.”

The new system tracks a larger number of small objects than previous space radars, about 200,000 objects, and makes 1.5 million observations per day, about 10 times the number made by existing or previous US assets.

The initial Space Fence facility is located at Kwajalein Atoll in the Republic of the Marshall Islands, near the Equator in the Pacific Ocean, with a second ground-based radar site envisaged for Western Australia.

In 2014 Lockheed Martin awarded the contract for the Space Fence’s ground structures to General Dynamics SATCOM Technologies. These include the receiving array, cooling equipment, radomes and other buildings. Space Fence uses gallium nitride (GaN) powered, S-band ground-based radars to provide the USAF with uncued detection, tracking and accurate measurement of space objects, primarily in low Earth orbit (LEO).

The geographic separation and higher wave frequency of the new Space Fence radars allow for the detection of much smaller microsatellites and debris than current systems. Furthermore Lockheed Martin’s Space Fence design significantly improves the timeliness with which operators can detect space events that could present potential threats to GPS satellites or the International Space Station (ISS).

The flexibility and sensitivity of the system also provide coverage of deeper space, geosynchronous orbits whilst maintaining the LEO surveillance fence.

The custom EMC filters provided by MPE were designed to meet the demanding performance specification flowed down from prime contractor Lockheed Martin. Supplied via MPE’s USA representative Technical Sales Solutions (TSS), they were installed on site by ATEC Industries (ATEC) of Elkridge, Maryland, USA. All units had been manufactured in their entirety at MPE and individually tested and certified ahead of shipping to ATEC in Maryland for subsystem integration.

Alongside the highly demanding performance criteria, of particular importance was the space envelope taken by the EMC filters and the mechanical design to allow ease of integration into subsystems on site. The custom filter suite delivered by MPE comprised a wide range of units for use in low current through to very high current applications.