Ahead of their exhibit at Space Tech Expo Europe 2017, Bob Stanton, Director of Technology - Omnetics Connector Corporation, outlines the company’s connectors for space systems.
Space technology electronic systems have evolved to meet the needs of long-range performance in extreme physical and environmental situations. From launch to deep space travel, the demands can be daunting, considering that they cannot fail, and cannot be repaired.
During launch from Earth, the high shock and vibrations that the craft goes through can damage somewhat standard electronic components. Omnetics’ connectors, for example, are mounted on printed circuit boards and must withstand potential sheering from the high G forces placed upon them. Since we all know that force is a product of mass times acceleration, we often select connectors as well as other components to be small, lightweight and of low profile. Mounting tabs and larger solder landing pads are also used in some applications. Space-oriented electronic circuits drive a number of other connector specifications. Since the electronics must not drain batteries quickly, many of the circuits are requiring very low voltages and low current flow to do their jobs. In addition, those circuits carrying digital images must carry massive amounts of images while sustaining high signal integrity to insure image quality. To do this, the Omnetics connectors and cable systems are designed to carefully match the impedance of the circuits and avoid distortion or ‘holes’ in the image base. Some lower elevation satellites scan the earth for images and process large image photos at very high frame rates, like a high-speed movie camera. The differential signal process for these systems is highly dependent upon the connector and cable electronic design, as well as the rugged reliability of the packaging.
Space-grade connectors are often descendants of military-grade connectors. As the new requirements are specified, connector design engineers use solid model software to modify the shells and mounting formats based on the specific application requirements. Quick adjustment to existing designs can be done economically and fit into unique shapes and formats for the high shock, vibration and long flight durations they are needed for. Specialty materials may also be needed to protect the electronics inside the space box, as outgassing of some polymers can be detrimental to the electronics. Specifications and tests are routinely used to assure the system meets the spacegrade requirements!
Space equipment predicted: Public and private corporations are expanding their own businesses and that will expand the market 100-fold in investments in small satellites. Launches are happening regularly now—and more of these launch vehicles are coming online and becoming operational. Companies such as Spire and Black Sky Global have in the past year gathered tens of millions in venture cash from the likes of Bessemer Venture Partners, Lemnos Labs, RRE Ventures and Vulcan Capital—investments that would’ve been hard to come by just a few years ago. Black Sky promises an earth imaging constellation that will deliver imagery more frequently than existing services currently do at a lower price point; Spaceflight Industries CEO Jason Andrews says Spire will offer a range of data services, most notably real-time maritime tracking of ships anywhere in the world and relevant weather data. To reduce size and weight, Omnetics offers a family of Power-Plus-Signal micro and nano connectors for space projects.
The two main growth categories according to Fortune magazine are space-based internet and high-resolution earth imaging. Some have likened the advent of reliable, space-based internet service as a second coming of the first internet boom. Small sats would provide technology capable of plugging new people and markets into the global web-based marketplace and enabling new business models (Facebook recently unveiled a solar-powered, broadband-beaming drone aircraft designed for the same purpose). Likewise, near-real time (or even real time) satellite imagery would allow global corporations to monitor all their assets at the same time and generate high-resolution visual data for individual companies, governments, or those trading on global financial markets.
Omnetics Connector Corporation is seeing both deep space and small sat technologies on the move. Early connectors have been supplied for many HEO (high elevation orbit) devices as well as cables and connectors that are working on the Mars Rover. They also serve SpaceX and Cube Sat, which are some of the early leaders in offering small sat and controlled size payloads mounted on to other launch vehicles as well. These piggyback space programmes are blooming and now more companies are investing in their own launch with private equipment onboard. Electronic features including SATA, higher speed digital frame-rate imaging with use of wiring such as that used in LVDS (low-voltage differential signals) are dominating the new circuit electronics for cables and connectors to handle.
For the lowest weight and rugged space performance, Omnetics Connector Corporation and others have released space grade Nano-D connectors. These MIL-DTL-32139 Nano-miniature connectors are approved for space programmes and inspected per EEE-INST-002.
Nano-D connectors at .025” pitch, are the smallest space-grade connectors on the market. Compared to larger Micro-D and D-Subminiature configuration, Nano-D connectors have reduced size and weight by as much as four times that of standard Micro-D connectors and eight times that of previous D-Sub footprints.
Better connectors, such as space connectors at Omnetics, use unique flex-pin gold-plated contacts that are polarized and shrouded by liquid crystal polymer insulators. The pin to socket strength and ‘lobed’ housing alignment system make these connectors capable of more than 2,000 mating cycles.
Omnetics space-grade connectors are available in a number of tail terminations. Standard pre-wired connectors come in 18” and 36” lengths with 80 micro inches of silver-plated 30 AWG (7-38) PTFE insulated wire. Board mount options include both surface-mount as well as thru-hole. If you are using a flex circuit, flex tails are also available. Shell finishes include nickel-plated aluminum, stainless steel and titanium.
Note that Cadmium plating and materials are prohibited for space applications. Pin and socket systems must be built and engineered to withstand the high shock and vibrational elements often associated with deep space exploration.
Key specifications for electronics in space materials must be addressed as well as test conditions and proof of space quality and survivability. Omnetics offers a free listing of key testing and materials specifications, such as materials outgassing, shock and vibration testing procedures, special plating requirements, and even hermetic sealing specifications and testing.
See more details at www.omnetics.com.