ASEN Aerospace Environments Introduction/Overview 1 ASEN-5335: Aerospace Environments Prof. Jeff Forbes & Prof. Jeff Thayer, Co-instructors Department of Aerospace Engineering Sciences Campus Box 429 University of Colorado Boulder, CO TIMED satellite tel: (Forbes) fax: (Forbes) office: ECOT-634 (Forbes) web page: Course Info Course Outline Lectures Learning Goals

ASEN-5335: Aerospace Environments The Space Weather of Solar-Planetary Interactions and Effects on Systems The various components of the Solar-Terrestrial System (Sun, Solar Wind Magnetosphere, Radiation Belts, Thermosphere, Ionosphere, Middle Atmosphere), and the interactions between them during both quiet periods and disturbance events, are examined to provide a solid understanding of the reentry and orbital environments within which aerospace vehicles operate. Throughout the course, perspectives on comparative planetary environments (including those of Mercury, Venus, Mars, Jupiter and Saturn) are provided. Objectives of the course are to provide: (1) an understanding of the general properties and characteristics of the geospace environment, and other planetary environments, including underlying physical mechanisms; (2) exposure to and practical experience with existing computer codes and algorithms that provide numerical estimates of various environmental parameters; and (3) an introduction to environmental hazards in space to man and equipment: particles and radiation, impact phenomena, spacecraft charging, orbital debris, aerodynamic drag, oxygen corrosion of surfaces, etc.

ASEN Aerospace Environments Introduction/Overview 3 Required Text: Introduction to the Space Environment, T.F. Tascione, Orbit Book Co., second edition, paperback, Grading: Grades will be based upon two exams (25% each) and a project (details to be provided later). Other Requirements: Access to the internet & Powerpoint (Access to a good library is desirable) Incompletes: No IF grades will be given unless a minimum of 50% of the course is completed (i.e., both exams or the project) Prerequisites: advanced undergraduate or graduate standing in engineering, physics, chemistry, atmospheric or space science, or equivalent background in the physical sciences.

ASEN Aerospace Environments Introduction/Overview 4 In addition to teaching you some things, Prof. Thayer and I will serve as your guides You are responsible for all of the learning goals for the course (see course web page) A lot of self-initiated learning will be involved in this course, especially through the project, which is intended to be challenging and will contain quantitative, analytic and computational components.

ASEN Aerospace Environments Introduction/Overview 5 Device Single Events (DSE) - anomalies – occurring in a piezoelectric accelerometer within the MOPITT (Measurements Of Pollution In The Troposphere) instrument aboard the Terra spacecraft.* A Brief Case-Study Introduction to Space Weather Effects on Satellite Instrumentation: The Terra spacecraft is instrumented to study a variety of land, ocean and atmospheric processes relevant to the evolution of climate as part of NASA’s Earth Science Enterprise. Terra was launched on December 18, 1999, into a ≈1040/2240 LT sun- synchronous polar (98.2 o ) orbit, and has an orbital period of minutes at an altitude of 705 km. *See Nichitiu et al., Solar particle events seen by the MOPITT instrument, JASTP, 66, , 2004; also

ASEN Aerospace Environments Introduction/Overview 6 The MOPITT instrument The MOPITT instrument is an infrared radiometer designed to measure CO and CH 4 in the troposphere. The infrared detectors need to be cooled to less than 100 K. The vibration level (i.e., due to pointing jitter, etc.), is measured by quartz piezoelectric shear accelerometers. The z-axis accelerometer sometimes experiences spikes

ASEN Aerospace Environments Introduction/Overview 7 Geographical Distribution of MOPITT DSEs MOPITT Device Single Events (DSE) March January % Polar Regions 70% in S. Hemisphere Day: Night ratio = 1.04 : % Galactic Cosmic Rays 54% South Atlantic anomaly (SAA) Day: Night ratio = 0.72 : 1.00 Geographical Distribution of DSEs What are the Temporal Dependences?

ASEN Aerospace Environments Introduction/Overview 8 TRACE Observation of a Solar Eruption Solar Proton Events (SPEs) are very large particle events with large fluxes of high-energy particles reaching the Earth. They are normally associated with large solar flares, explosive events that occur over time scales of minutes to hours.

ASEN Aerospace Environments Introduction/Overview 9 Very Energetic protons reach Earth in less than 30 minutes Less than 1 hour after the initial proton arrival the POLAR/VIS imager is saturated and remains so for almost a day. VIS-proton-Bastille 2000 Bastille Day Solar Flare

ASEN Aerospace Environments Introduction/Overview 10 These Energetic Particles Also Pose Dangers to Astronauts

ASEN Aerospace Environments Introduction/Overview 11 Time series of DSE daily rate vs. SPE peak proton flux Yn = large SPEs that affect the DSE daily rate Nn = large SPEs with no effect on the DSE daily rate Fluxes scaled to fit on plot 27-day running mean

ASEN Aerospace Environments Introduction/Overview 12 The energetic particles detected by the MOPITT (piezoelectric) accelerometer are mainly high energy protons precipitating at high latitudes MOPITT Accelerometer Anomalies During Intense SPE MOPITT DSEs are well correlated with SPE proton fluence (i.e., total number of particles greater than 15 MeV)

ASEN Aerospace Environments Introduction/Overview 13 MOPITT DSEs Correlate with Solar activity Mopitt DSE over SAA (27 days average) F10.7 cm (Smooth 27 days average) DOY (from 2000) The relative importance of SAA vs. polar regions also changes with solar activity

ASEN Aerospace Environments Introduction/Overview 14 Solar Activity Varies with an 11-year Periodicity