Compared to pushing products from Earth to the market, launching products into space is much more complex. Components in space must be able to withstand the challenges of the space environment, operate reliably and maintenance free within their expected lifespan, and support the weight and size limitations of launches.
In this environment, product designers turn to aerospace qualified parts (QPS) that have already been designed, tested, and reviewed for successful use in space applications. QPS has reached the maximum technology maturity level (TRL) set by the National Aeronautics and Space Administration (NASA) of the United States.
TRL is divided into levels 1 to 9, reflecting the process of the product from concept to mature performance (Figure 1). TRL 1 to 3 demonstrate how the product theoretically operates, from basic concepts to concept validation. TRL 4 to TRL 6 cover preliminary testing and simulation. TRL 7 and 8 have passed prototype testing and final technical demonstrations, turning concepts into reality.
NASA TRL process image
Figure 1: NASA TRL represents the process of aerospace products from initial concept to performance maturity. Only parts with a TRL of 9 can be considered QPS parts after being manufactured and tested according to recognized standards. (Image source: Cinch Connectivity Solutions)
Products with TRL reaching level 9 have achieved success in practical space applications. In addition to achieving this high TRL level, the parts also need to pass specific testing procedures in order to be considered QPS. The standards for controlling these requirements vary depending on the type of part. For example, QPS attenuators must be tested according to MIL-DTL-3933 T-level standards, while QPS electronic connectors are governed by NASA's EEE-INST-002 standard.
Understanding the specific challenges faced by space-based applications can help designers select existing QPS with performance that meets their requirements, shorten the time from concept to deployment, and bring products to market on time and within budget.
Overcoming degassing
The ability to operate in vacuum and extreme temperatures is one of the biggest obstacles that space components must overcome. The vacuum in the medium Earth orbit (MEO) at a distance of 1234 to 22234 miles from Earth, where Global Positioning System (GPS) satellites operate at this altitude, has an average vacuum degree of 1 mTorr to 1 µ Torr. At the same time, the components in these and other applications have temperatures as low as -270 ° C in shadow and as high as+121 ° C in direct sunlight.
Non metallic parts may experience "degassing" when exposed to vacuum and high temperature environments. This phenomenon refers to the migration of gases remaining inside the material during the manufacturing process towards the surface. This migration may lead to cracks inside the material, thereby weakening its strength. The released gas may also condense and freeze on other parts, causing damage to optical components such as blurring and sensor blockage.
The severity of degassing is measured by the total mass loss (TML) of the component under vacuum and thermal conditions, expressed as a percentage of the original mass. Manufacturers also measure the percentage of volatile condensable material (CVCM) that can be collected, which is the amount of degassed material that condenses on colder surfaces. Both tests were conducted in accordance with the ASTM E595 protocol, which requires samples to be kept at+125 ° C and below 5 x10-5 Torr for 24 hours.
Most electronic components must undergo degassing testing to be designated as QPS parts due to the use of non-metallic insulation and shielding materials. Cinch Dura Con from Cinch Connectivity Solutions ™ The space shielded micro-D plug and socket (Figure 2) are in this situation. The non-metallic, thermosetting insulation around the pins, and ethylene tetrafluoroethylene (ETFE) wire insulation layer in Dura Con connectors have a loss of less than 1% of their total weight and a CVCM of less than 0.01% during testing.
TE Connectivity Dura Con connector image
Figure 2: The Dura Con connector uses low degassing insulation material, which exceeds the requirements of NASA's EEE-INST-002 standard for LEO application electronic connectors. (Image source: Cinch Connectivity Solutions)
These nickel plated connectors comply with MIL-DTL-83513 standard and are suitable for micro rectangular electrical connectors. They can accommodate 9 to 100 needle positions, with a base width of 0.775 "to 2.160" and a height of 0.298 "to 0.384".
According to NASA's EEE-INST-002 electronic connector selection criteria, the design and low degassing level of these connectors make them suitable for low Earth orbit (LEO) at altitudes up to 1200 miles. The Hubble Space Telescope, the International Space Station, and a constellation of microsatellites that make global telecommunications possible are all operating in orbit in this region.
The EEE-INST-002 standard also specifies three criticality levels for electronic connectors. Level 1 connectors are mission critical connectors, Level 2 connectors require high reliability, and Level 3 connectors are standard reliability levels. Dura Con connectors are classified as level 2.
Reduce radiation interference
In addition to the hazards of vacuum and extreme temperatures, components in space must also be able to withstand higher levels of radiation. Without the protection of the Earth's atmosphere, these components would be exposed to full spectrum ultraviolet (UV) radiation. Beyond low Earth orbit, gamma rays and other ionizing radiation are also a concern. Radiation can shorten the lifespan of non-metallic components and typically reduce the quality of electromagnetic signals through radio frequency interference (RFI) and electromagnetic interference (EMI).
Electrical connectors like Cinch Connectivity Solutions' Tromper QPS electrical connector, which can solve this problem, have strong RF interference and electromagnetic interference shielding functions, and can meet the requirements of MIL-STD-1553B data bus specification.
They are also mainly made of metal, including gold-plated beryllium copper contacts and nickel substrates. Low degassing polytetrafluoroethylene (PTFE) dielectric material can achieve TML less than 1.0% and CVCM less than 0.10%.
The space level Tromper series includes two types of small connectors for connection. The TRB connector adopts a bayonet lock (Figure 3), while the TRT connector adopts a threaded connection (Figure 4). Each type offers multiple designs to allow for connections through boards, cable terminations, or printed circuit boards (PCBs).