AIAA RM Second ATS at UCCS Polar-Orbiting, Passive, Atmospheric Calibration Spheres (POPACS) Presented by R. Gilbert Moore Director, Project POPACS Monument, CO

AIAA RM Second ATS at UCCS Statement of the Problem Upper atmospheric drag causes the orbits of Low Earth Orbiting (LEO) spacecraft to decay, over time Re-boosts from on-board propulsion systems are required to maintain orbits of high-value assets and maneuvering burns are sometimes required to avoid collisions with orbital debris

AIAA RM Second ATS at UCCS International Space Station Orbit Decay Due to Atmospheric Drag, Showing Re- boosts from Zarya Module

AIAA RM Second ATS at UCCS Complications from Solar Storms Solar flares and Coronal Mass Ejections temporarily heat up and increase the density of Earth’s upper atmosphere at satellite altitudes by as much as three orders of magnitude These events cause increased drag on Low Earth Orbiting (LEO) spacecraft and debris The ability to predict collisions between spacecraft and orbital debris is complicated by these random density increases

AIAA RM Second ATS at UCCS Sunspot, Flare and Prominences

AIAA RM Second ATS at UCCS Solar Cycle 24

AIAA RM Second ATS at UCCS Coronal Mass Ejection (CME)

AIAA RM Second ATS at UCCS CME Effect on Earth’s Magnetic Field and Upper Atmosphere

AIAA RM Second ATS at UCCS POPACS Mission Objectives Measure variations in atmospheric density resulting from solar storms during the descending phase of Solar Cycle 24 and all of Solar Cycle 25 Use the density data to help improve orbital collision avoidance accuracy Involve university students in all facets of a solar-terrestrial physics research project

AIAA RM Second ATS at UCCS Methodology Launch small, hollow Aluminum spheres, ballasted to differing masses, into near-polar elliptical orbits Track the spheres with Space Command radars and network of university student “Go To” telescopes Compute the spheres’ orbits Calculate atmospheric density from the amount that the spheres’ apogees shrink as a result of atmospheric drag at each perigee pass

AIAA RM Second ATS at UCCS Methodology (cont.) Measure northern and southern auroral region atmospheric densities before, during and after arrival of solar coronal mass ejections (CMEs) Observe the way that high-latitude density increases migrate to the equator Use density variation data to improve short-term predictability of satellite and debris orbits during future solar storms Help improve accuracy of orbital collision avoidance forecasts and our basic understanding of solar-terrestrial relationships

AIAA RM Second ATS at UCCS Program Status Three 10 cm diameter Aluminum spheres with masses of 1, 1.5 and 2 kilograms were deployed into orbit on 9/29/2013 from SpaceX’s Falcon 9v1.1 ELV launched from Vandenberg AFB The orbit is inclined 80 degrees to the equator, with a period of minutes, a perigee altitude of 318 km and an apogee altitude of 1488 km. Predicted sphere orbit lifetimes are 10, 12.5 and 15 years, with the lightest sphere de-orbiting and being consumed by aerodynamic heating first

AIAA RM Second ATS at UCCS POPACS Spheres and Spacers

AIAA RM Second ATS at UCCS Falcon Vandenberg

AIAA RM Second ATS at UCCS Falcon 9v1.1 Launch – 9/29/2013

AIAA RM Second ATS at UCCS CSD Deployment of Spheres and Spacers

AIAA RM Second ATS at UCCS SSN Tracking of POPACS Spheres

AIAA RM Second ATS at UCCS Tracking The Joint Space Operations Center (JSpOC) is currently radar tracking the spheres with its Space Surveillance Network sensors and publishing the spheres’ Two-Line Element sets (TLEs) Analytical Graphics, Inc. and Utah State University are coordinating a U.S. network of university student “Go To” telescopes and professional telescopes to track and capture images of the spheres. The students will calculate the spheres’ orbital elements using their sphere images, star charts and pattern recognition software and then calculate atmospheric densities at the orbits’ perigee locations

AIAA RM Second ATS at UCCS “Go To” Telescope with GPS Receiver, Computer and Recorder

AIAA RM Second ATS at UCCS Example Sequence from Go To Tracking of Satellites

AIAA RM Second ATS at UCCS Data Analysis Our student teams will monitor solar storms during the remainder of Solar Cycle 24 and all of Solar Cycle 25 and correlate their atmospheric density data with the intensity of those storms Their data will be combined with radar-derived data to help improve the accuracy of Air Force and Naval Research Laboratory atmospheric density models and collision avoidance forecasts

AIAA RM Second ATS at UCCS Contact Information Additional universities in the U.S. and around the world are welcome to participate in the tracking and analysis phases of the POPACS project Contacts: For tracking, For analysis, For general info.,

AIAA RM Second ATS at UCCS Thanks to our team members