Spitzer Space Telescope Handbook Spitzer Heritage Archive Documentation Version 3.0, 8 January 2021 Table of Contents Spitzer Space Telescope Handbook ..................................................................................... i Chapter 1. Introduction ................................................................................................. 6 1.1 Document Purpose and Scope ........................................................................................ 6 1.2 How to Contact Us ......................................................................................................... 6 1.3 Standard Acknowledgements for Spitzer Publications .................................................. 6 Chapter 2. Spitzer History and Mission Overview ....................................................... 7 2.1 History and Organization of the Spitzer Project ............................................................. 7 2.2 Spacecraft Development ............................................................................................... 11 2.2.1 A Prime Directive ..................................................................................................... 11 2.2.2 A Kinder, Gentler Orbit ........................................................................................... 11 2.2.3 Flight System Architecture ....................................................................................... 12 2.2.4 The Spitzer Warm Mission ....................................................................................... 14 2.2.5 The Spitzer Beyond Mission ..................................................................................... 14 2.2.6 The Rest of the Story ................................................................................................ 15 2.3 Principal Investigators, Science Team, and User Community ..................................... 16 2.3.1 Evolution of the Spitzer Science Working Group ..................................................... 17 2.3.2 Spitzer Scientific Utilization ..................................................................................... 17 Chapter 3. Observatory Description ........................................................................... 20 3.1 Overview ...................................................................................................................... 20 3.2 Observatory Description ............................................................................................... 21 3.3 Science Instrument Operations ..................................................................................... 23 3.4 Observatory Design and Operations Concept .............................................................. 26 3.4.1 The Warm Launch and Telescope Temperature Management ................................ 29 3.4.2 Data Storage ............................................................................................................ 30 3.4.3 Data Transmission ................................................................................................... 30 3.5 Sky Visibility ................................................................................................................ 32 3.5.1 Solar Orbit ............................................................................................................... 32 3.5.2 Pointing Constraints ................................................................................................ 33 3.5.3 Viewing Periods ....................................................................................................... 35 3.5.4 How Visibility Evolves with Time ............................................................................ 38 3.5.5 Orientation of Focal Plane and Slits against the Sky .............................................. 38 3.5.6 Bright Object Avoidance .......................................................................................... 39 3.6 Operational Constraints – Instrument Campaigns ........................................................ 39 3.7 Pointing Capabilities .................................................................................................... 40 3.7.1 Pointing Control System .......................................................................................... 40 3.7.2 Pointing Accuracy and Stability ............................................................................... 41 3.7.3 Scanning Stability and Performance ........................................................................ 42 3.7.4 Tracking Capabilities ............................................................................................... 42 3.7.5 Pointing Reconstruction ........................................................................................... 42 3.8 Optical Design .............................................................................................................. 43 ii 3.9 Optical and Thermal Performance ................................................................................ 44 3.9.1 Surface Accuracy ..................................................................................................... 44 3.9.2 Wave-front Errors .................................................................................................... 45 3.9.3 Throughput ............................................................................................................... 45 3.9.4 Stray Light Rejection ................................................................................................ 46 3.9.5 Telescope Temperature/Thermal Background ......................................................... 48 3.9.6 Telescope Focus ....................................................................................................... 48 3.10 Focal Plane Layout ....................................................................................................... 48 Chapter 4. Observatory Operations ............................................................................ 52 4.1 Spitzer Science Center .................................................................................................. 52 4.2 Spitzer Science Operations Overview .......................................................................... 52 4.2.1 The Life Cycle of a Spitzer Observation .................................................................. 52 4.2.2 Data Products .......................................................................................................... 57 4.3 Astronomical Observation Templates – AOTs ............................................................ 57 4.4 Astronomical Observation Request – AOR ................................................................. 58 4.5 Science User Tools ....................................................................................................... 59 4.5.1 Spot ........................................................................................................................... 59 4.5.2 Performance Estimation Tool (PET) ....................................................................... 60 4.5.3 Spitzer Heritage Archive .......................................................................................... 60 4.6 Solar System Objects - SSOs ....................................................................................... 60 4.6.1 Tracking Performance ............................................................................................. 61 4.6.2 Ephemeris Management ........................................................................................... 61 4.7 Targets of Opportunity - ToOs ..................................................................................... 62 4.8 Generic Targets ............................................................................................................ 62 4.9 Second-Look Observations .......................................................................................... 62 4.10 List of Safings or Standbys in the Mission ................................................................... 62 Chapter 5. Spitzer Cross-Calibration .......................................................................... 64 5.1 Observations ................................................................................................................. 64 5.2 Stellar Cross-Calibrators .............................................................................................. 64 5.3 Red Cross-Calibrators .................................................................................................. 64 Chapter 6. Spitzer Archive ......................................................................................... 66 6.1 Level 0, or Raw Data .................................................................................................... 66 6.2 Level 1, or Basic Calibrated Data (BCD) ..................................................................... 66 6.3 Calibration Files ........................................................................................................... 67 6.4 Level 2, or Extended Pipeline Products (Post-BCD) ................................................... 67 6.5 Calibrated Data Units ................................................................................................... 67 Appendix A. Infrared Astronomy ............................................................................... 68 Infrared Flux Units ....................................................................................................................