The space environment is surrounded by different physical phenomena. These phenomena, degrade space electronics and for this reason it is necessary to qualify the hardware before flight.
COTS (Commercial Off The Shelf) components will be used in small satellites mostly without qualification (upscreening). Qualification tests are very complex and expensive. Space-COTS are COTS components qualified for space missions and following international standards. Due to a new industrial test concept Space-COTS match small satellite mission requirements efficiently and offer the best Price/Quality ratio for space hardware manufacturing.
At the beginning of the space era, no space electronics were available at all. Military electronic parts were up-screened for its use in space. In this up-screening process, complementary tests were achieved and the best of them were selected.
In 1973, the Skylab hardware was manufactured using military components. After the qualification test, the hardware has to be improved several times due to encountered malfunctions during the qualification process. These improvements implicated further investments over 3 million dollars for achieving system redundancy; new electronic components and further qualification campaigns were needed.
The electronic systems of the first space shuttle mission (1981) were based also on military elements. In order to increase the reliability of the system most of them were built six fold. Using an elective scheme, the valid data was verified. The inclusion of redundant systems meant also the increase of weight, power consumption and more hardware and software challenges.
Due to the fact that military electronics were not good enough for space applications and that the up-screening does not always improve the parts, in the 60’s the systematic development of space electronics was initiated. The manufacture of space electronics demands a high quality production process. In the USA military components were selected and thereafter qualified running additional tests. This strategy allowed the reduction of production costs. Since the space components demand was and is small, the price of these is still high. Nowadays the qualification of only one component following ESA or NASA Standards implies an investment beginning from 1 million dollar and a certification time of around two years.
The gained experience of the last sixty years in many space missions and with different technologies allowed institutions like ESA and NASA to develop qualification guidelines and standards, which are manuals to be followed and used for the qualification of electronic parts for space missions.
A full qualification of a component is very laborious. It takes few years and requests a high financial investment. A full qualification is called “Screening Test”. In the screening test following tests have to be performed:
- Electrical test
- Seal test
- Visual inspection
- Mechanical shocks
- Vibration test
- Constant acceleration
- Thermal test
- Radiation test
- High Temperature Stabilization Bake
- Temperature cycling
- Thermal Shock
Overqualification? Are COTS robust enough?
ITAR components comply with very severe requirements and offer a high reliability for their usage in extreme environments. An ITAR component can have a radiation tolerance of 300 krad. During a LEO mission, a total dose of 1 krad will be accumulated in one year . In this case the use of ITAR components does not match the mission requirements. It is valid to say that the ITAR components are over-qualified for LEO missions.
Furthermore, the ITAR problematic is bound with export restrictions. The export licensing process takes around six months and there is no guarantee to get the permission. This is a major problem for small and medium-sized enterprises (SMEs) also American SMEs and retards their business process. Another disadvantage is that the ITAR EEE parts are based on a robust but also old technology, and do not reach the newest High-Tech electrical and functional levels. Another important point is the price of ITAR components, which is very high and a financial obstacle for SMEs that want to enter in the space field and are not in possession of major capital resources.
The new space era begins with the born of the Picosatellites. In February 2000 the Stanford University launched the microsatellite OPAL. This satellite was the mothership of six Picosatellites, which demonstrated the feasibility of new space platforms for research experiments . Since the beginning of the century such new space platforms has been used by many universities, research institutes and space companies for research, technology demonstration, technology validation and commercial services. In order to keep costs low, Commercial-Of-The-Shelf (COTS) components have being used. These components support the missions for a limited period, however reborn the usage of COTS components in space.
Nowadays many institutions continue developing and launching nanosatellites based on COTS. The installed components will be in very rare mission qualified or even the use of very few ITAR components happened. Most of these missions never qualify the electronic components and trust in the performed simulations and to luck. In the best case the developing teams do test the electronics but in a module level or a board level. During this process, the electronic board will be irradiated with gamma rays and will be tested with a test software until errors appear or in case nothing happen the test will be considered as passed. This solution is often practiced however; it is not the professional way to develop space electronics. The standard procedure from the ESA and NASA testing each component is the recommended way to design electronics for space, especially because is necessary to understand the behaviour of all components under such conditions. In conclusion, each component of the system should be tested in order to comply with the mission requirements, and the components must be selected before the mission design begins. The uncertainty of not knowing for how long the electronics will properly work in space will never permit the professional development of small satellites, what is a necessity for high quality commercial services and products.
NewSpace is a terminology, which represents the philosophy related to the emerging private space industry. This community is built mainly from space companies involved in the development of low-cost space technologies and the definition of low-cost policies. In other words the space technology will be to a mass product and practically accessible for everybody .
It is important to remark that ITAR solutions do not match with the NewSpace philosophy and in consequence, new solutions have to be found.
One of the most interesting parameters for devices in space is the radiation robustness. Such parameter cannot be found in the datasheets of commercial parts. All electronic components could survive in space but the question is for how long!
In the datasheet of a commercial component, the behaviour of the electrical parameters under normal conditions (on the ground) will be assessed. In addition, the limits of these parameters can be found. For instance in the datasheet is possible to read the Absolute Maximum Ratings like the temperature limits, let say from -10°C to +50°C. It does not mean that under or above these limits, the component will not work anymore. A test in a thermal-chamber will show the real limits of the component, following the example above i.e. from -15°C to +58°C. It means the same components could be used for a broader temperature range than specified in the datasheet. In general it is possible to see how robust is an electronic component measuring its behaviour under specific environment conditions.
The NewSpace philosophy and the approach described above are merged in the Space-COTS project.
The most important impact of the Space-COTS is the support of the NewSpace philosophy and the emerging private space industry.
The Space-COTS story
After the text edit has been completed, the paper is ready Space-COTS is a pure NewSpace concept and allow the access to commercial components qualified for space.
Jaime ESTELA, from the German/Peruvian Company Spectrum Aerospace, invented the term “Space-COTS” and its concept. The research work started in 2008 by supporting CubeSat projects in Europe and in South America. In this process, a deep knowledge of the CubeSat technology and its requirements and constraints was gained. Furthermore, the experience in research corroborated the use of commercial electronics in the space business. Working for the German Aerospace Agency (DLR) in satellite projects and the close contact to ESA standards gave an understanding of the long and expensive way of the traditional qualification of EEE parts. The DLR’ Standardization and EEE-Parts Division and the ESA Component Space Evaluation and Radiation Effects Section instructed the Spectrum Aerospace team the concept and philosophy of the test procedures for EEE parts.
This experience crystallized in the innovative concept of the Space-COTS finding the middle point between not qualified parts at all (i.e. in CubeSats) and full qualified ITAR parts. Looking at the small satellite history many commercial parts can work in space for several years although they were not designed for space applications. However, reliable commercial EEE parts have to be identified. Middle of 2015 due to the participation in the Horizon-2020 program a feasibility study was conducted, where Jaime Estela (author) evaluated the components used in different satellites and identified the most used parts. The result of this study led to edition of the first Space-COTS catalogue. The aim of this catalogue is to list the major quantity of active and passive components, mechanical parts and materials covering almost all the space mission needs. This solution is more efficient and creates at the start phase the same situation like by the traditional satellite developers, where they get a list of ITAR components that they have to take for any design. The idea is to offer later a broader selection of components so that the Space-COTS catalogue will be similar as the component manufacturers and distributors.