7 March 2005ODTÜ UYDU TKN.1 Space Weather (SpW) Near Earth Space Environment (NESE) Implications for Spacecraft (S/C) Design Yurdanur Tulunay, Ph.D., Space Research, UK, 1972

7 March 2005ODTÜ UYDU TKN.2 keywords-statements Spaceweather (SpW) NESE interacts with S/C engineering subsystems and payloads ancient dream Traveling among the stars, the planets, moon

7 March 2005ODTÜ UYDU TKN.3 Isaac Newton 260 years ago had a complete understanding of what was required to place an object in orbit around E +

7 March 2005ODTÜ UYDU TKN Technological ability to leave the E + ’s surface First steps in exploration of our solar system

7 March 2005ODTÜ UYDU TKN.5 challenge Difficulty of getting a S/C into orbit S/C must be designed to operate in environments that are quite different from those found on the E + ’s surface.

7 March 2005ODTÜ UYDU TKN Database of 2779 S/C anomalies related to interactions with NESE (The Nat. Geophyl. Data Center, Boulder, Co., USA) NASA and AF S/C studies: ~20-25% of all S/C failures are related to NESE (Tribble, 1995)

7 March 2005ODTÜ UYDU TKN.7

7 March 2005ODTÜ UYDU TKN NASA recognised the importance of the field of NESE by forming a national program to coordinate a efforts in this area International Standards Organisation (ISO) under charter from the UN formed a Space System Technological Comm. one of the missions was to develope internationaly recognised NESE standards. (Song, et al., eds., 2001)

7 March 2005ODTÜ UYDU TKN June 1st doc. by Anderson, B.J. (Ed.) Natural Orbital Environment Guidelines for use in Aerospace Vehicle Development NASA Technical Manual

7 March 2005ODTÜ UYDU TKN Space Weather and the ESA feasibility studies Space Weather Applications Pilot Project including Service Development Activities (SDA) (Jansen, et al., 2004) SWWT 1999 – today Space Weather Working Team European Union (FP5, FP6 and FP7) and Space Weather

7 March 2005ODTÜ UYDU TKN.11 Seek to bridge the gap between space physics and astronautical engineering ►NESE◄ i.e. Emphasis on the facets of the NESE that may degrade S/C subsystems

7 March 2005ODTÜ UYDU TKN.12 objective To obtain an understanding of the relationship between: NESE and S/C or Space inst., operating principals and design alternatives.

7 March 2005ODTÜ UYDU TKN.13 content description of the NESE a discussion of the ways in which the NESE may interact with an orbiting S/C by relating the various NESE interactions to S/C design specifics

7 March 2005ODTÜ UYDU TKN.14 justification Understanding these relationships is important to S/C designers-must develop a spacecraft capable of operating in specified orbital environment Payload providers-must provide instrumentation capable of delivering high quality data under potentially adverse conditions

7 March 2005ODTÜ UYDU TKN.15

7 March 2005ODTÜ UYDU TKN.16 S/C design Regardless of the specific nature of the payload, all the S/Cs must perform certain basic functions in order to enable the payload to function properly.

17

7 March 2005ODTÜ UYDU TKN.18 finally A physical structure to accomodate systems and payloads

7 March 2005ODTÜ UYDU TKN.19 Most S/Cs can be grouped into one of the three orbital altitude range: LEO MEO (HEO) GEO

7 March 2005ODTÜ UYDU TKN.20 LEO: perigee<1000 km altitude region space shuttle operates mostly, typically reserved for i) largest operational payloads (e.g. space station-Skylab, Mir, Salyut) or ii) S/C need a close view of the E + (e.g. LANDSAT, TIROS, DMSP)

7 March 2005ODTÜ UYDU TKN.21 MEO (or HEO): perigee: km altitude range e.g. mostly reconnaissance sattelites placed on highly elliptical orbits. GEO: altitude km Popular with various surveillence and communication S/Cs.

7 March 2005ODTÜ UYDU TKN.22 (Tribble, 1995)

7 March 2005ODTÜ UYDU TKN.23 S/C’s orbital altitude and orbital inclination (i). i=f(altitude) ( A given launch vehicle can launch the heaviest possible payload into an inclination=latitude of the launch site) major impacts on the type and magnitude of NESE effects experienced by a S/C.

7 March 2005ODTÜ UYDU TKN.24 (Tribble, 1995)

7 March 2005ODTÜ UYDU TKN.25 (Fortescue, Stark, eds, 1995)

26 (Fortescue, Stark, eds, 1995)

7 March 2005ODTÜ UYDU TKN.27 (Fortescue, Stark, eds, 1995)

7 March 2005ODTÜ UYDU TKN.28 conclusion NESE may have a direct impact on a S/C subsystem’s ability to execute its design objective. Depending on the severity of the orbit, these interactions may be quite mild or may be mission threatening.

7 March 2005ODTÜ UYDU TKN.29 SPACE ENVIRONMENTS VACUUMNEUTRALPLASMARADIATIONMM/OD SPACE SYSTEMS Solar UV Outgassing & Contamination Aerodynamic Drag Sputtering Atomic Oxygen Attack Spacecraft Glow Spacecraft Charging Van Allen Belts Galactic Cosmic Rays Solar Proton Events Impacts Altitute Determination & Control Degradition of Sensors Induced Torques Change in sensor coating Interference with sensors Torques due to induced potentials Avionics Upsets due to EMI from arcing Degradition: SEU's, bit errors,... EMI due to impacts Electrical Power Change in coverslide tranmissions Change in coverslide transmittance Shift in floating potential, reatraction of contaminants Degradition of solar cell output Destruction/ Obscuration of solar cells Propulsion Thruster plumes may be a contaminant source Drag makeup Fuel Requirements Shift in floating potential due to thruster firings Rupture of pressurized tanks Structures EMI due to impacts Telemetry, Tracking & Communications Degradation of sensors Change in sensor coating Interference with sensors EMI due to arcingDegradition of electronics EMI due to impacts Thermal Control Change in surface alpha / epsilon ratio Reatraction of contaminants Cold surfaces may be experience heating Degradition of alpha / epsilon ratio (Fortescue, Stark, eds, 1995)

30