Polar-Orbiting, Passive, Atmospheric Calibration Spheres (POPACS)

1. Polar-Orbiting, Passive, Atmospheric Calibration Spheres (POPACS) Presented by R. Gilbert Moore Director, Project POPACS Monument, CO AIAA RM Second ATS at UCCS 10-25-2013

2. 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 10-25-2013

3. International Space Station Orbit Decay Due to Atmospheric Drag, Showing Re-boosts from Zarya Module AIAA RM Second ATS at UCCS 10-25-2013

4. 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 10-25-2013

5. Sunspot, Flare and Prominences AIAA RM Second ATS at UCCS 10-25-2013

6. Solar Cycle 24 AIAA RM Second ATS at UCCS 10-25-2013

7. Coronal Mass Ejection (CME) AIAA RM Second ATS at UCCS 10-25-2013

8. CME Effect on Earth’s Magnetic Field and Upper Atmosphere AIAA RM Second ATS at UCCS 10-25-2013

9. 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 10-25-2013

10. 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 10-25-2013

11. 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 10-25-2013

12. 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 100.3 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 10-25-2013

13. POPACS Spheres and Spacers AIAA RM Second ATS at UCCS 10-25-2013

14. Falcon 9v1.1 @ Vandenberg AIAA RM Second ATS at UCCS 10-25-2013

15. Falcon 9v1.1 Launch – 9/29/2013 AIAA RM Second ATS at UCCS 10-25-2013

16. CSD Deployment of Spheres and Spacers AIAA RM Second ATS at UCCS 10-25-2013

17. SSN Tracking of POPACS Spheres AIAA RM Second ATS at UCCS 10-25-2013

18. 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 10-25-2013

19. “Go To” Telescope with GPS Receiver, Computer and Recorder AIAA RM Second ATS at UCCS 10-25-2013

20. Example Sequence from Go To Tracking of Satellites AIAA RM Second ATS at UCCS 10-25-2013

21. 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 10-25-2013

22. 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, t.s.kelso@centerforspace.net • For analysis, jjsojka@usu.edu • For general info., gilmoore12@aol.com AIAA RM Second ATS at UCCS 10-25-2013

23. Thanks to our team members AIAA RM Second ATS at UCCS 10-25-2013