Tham khảo tài liệu 'mems and microstructures in aerospace applications - robert osiander et al (eds) part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 68 MEMS and Microstructures in Aerospace Applications expectancies of missions have continued to grow over the years from 6 months on early TIROS weather project to the current requirements of 30 years for the International Space Station ISS . The Telstar 1 launched in 1962 had a lifetime of 7 months compared to Telstar 7 launched in 1999 with a 15 year life expectancy. Albeit the earlier Telstar weighed in at only 78 kg and cost US 6M compared to the 2770 kg Telstar 7 at a cost of US 200M. The geostationary operational environmental satellites GOES carry life expectancies greater than 5 years while current scientific satellites such as TERRA and AQUA have life expectancies greater than 6 years. Military-grade satellites such as Defense Satellite Communication System DSCS have design lives greater than 10 years. To assure long-life performance numerous factors must be considered relative to the mission environment when determining requirements to be imposed at the piece part MEMS device level. The high reliability required of all space equipment is achieved through good design practices design margins . derating and manufacturing process controls which are imposed at each level of fabrication and assembly. Design margins ensure that space equipment is capable of performing its mission in the space environment. Manufacturing process controls are intended to ensure that a product of known quality is manufactured to meet the design requirements and that any required changes are made based on a documented baseline. MEMS fall under the widely accepted definition of part as used by NASA projects however due to their often multifunctional nature such as electrical and mechanical functions they may well be better understood and treated as a component. The standard NASA definitions are Part One piece or two or more pieces joined which are not normally subjected to disassembly without destruction or impairment of designed use. Component A combination of parts devices and
