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Astronomers Learn to Work in Space. Detectors Pointing and Stability Data Storage Contamination Thermal Control Background radiation. Technical Challenges. V-2 Rocket October 10, 1946 Ultraviolet spectrum of sun 340 nm – 240 nm Bead entrance UV film. First Astronomy from Space.
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Detectors Pointing and Stability Data Storage Contamination Thermal Control Background radiation Technical Challenges
V-2 Rocket October 10, 1946 Ultraviolet spectrum of sun 340 nm – 240 nm Bead entrance UV film First Astronomy from Space
Geiger counters Proportional counters Solid state detectors Scintillation detectors X-ray and Gamma Ray Detectors
Rotating Grating Spark Chamber Cerenkov counter Grazing Incidence telescope X-ray and Gamma RayImagers
Small Astronomical Satellites • Three unstabilized survey satellites • SAS A (Uhuru) – Rotating Grating • SAS B – spark chamber • SAS C tandem proportional counters
Film Photomultipliers Vidicons SEC Vidicons IPCS Digicons CCDs Optical and UV Detectors
Human Assisted Missions • Gemini – hand-held near UV spectrograph • Apollo – Spectrometer on moon • Skylab – ATM, Small UV spectrograph, various X-ray experiments • Spartan • Spacelab
3 rate gyros + high trust jets to slow tumble at launch <0.75o/s 3 wide-angle solar cells + gyros to orient satellite to sun-line 8 10o solar cells to orient satellite within 0.25o 6 star trackers (f.o.v. =1o) set to pick up at least 3 stars no fainter than magnitude 2 within 15 arc sec of predicted position Bore-sight star tracker to 2arcsec Fine rate gyros counteract drift Electro-magnets interact with terrestrial field to unload fine gyros with gas jets only a backup OAO Pointing Systems
Magnetic core memory 100 kbits Analog data could be transmitted in real time only 40-foot dishes in Quito and Santiago 85-foot dish in Rosman, NC Commands transmitted to stations and data returned by teletype Microwave link available between control station at Goddard and Rosman Automatic safe mode if commands discrepant Data Handling for OAO
OAO A: Standard quartz mirrors OAO B: Be mirror OAO C: Egg-crate quartz mirror OAO Mirrors
Detectors: Bolometer Solid state Heterodyne Survey Satellite: IRAS (1983) Infrared Observations
Two V antennas each with 229m arms 37m dipole 1968: Earth orbiter 1973: Lunar orbiter Radio Astronomy Explorer