Federated Ground Station Network Spangelo et al. Capacity Assessment

Motivation FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

1 March 2010 Motivation

Existing communication systems designed for single missions and highly constrained. Spangelo et al. •Many small satellites communicate only to one or a handful of dedicated ground stations. •Existing ground stations are monolithic in design and largely underutilized. Motivation FGSN Contributions Growing number of satellite developers planning science missions Network Model face ground station infrastructure limitations Capacity • Satellites are unable to maintain 24/7 coverage with current gro und stations. Assessment •Systems are complex, non-standardized, and have reliability issues. Conclusion Future Work Potential Solution: Federated Ground Station Network (FGSN)

2 March 2010 Federated Ground Station Networks (FGSNs) FGSN: Synergy of autonomous, globally distributed ground stations 1 Internetenabled communication system where ground

Spangelo et al. stations are independently owned + loosely cooperative

Motivation FGSN Contributions Network Model Capacity Assessment Conclusion Internet Future Work

1J. Cutler, P. Linder, and A. Fox, “A Federated Ground Station Network,” in SpaceOps Conference Proceedings, October 2002. 3 March 2010 Federated Ground Station Networks (FGSNs)

FGSN Advantages:

•Communication opportunity, dynamic, flexible framework Spangelo et al. •Science Missions: constellations capture data to avoid space and time aliasing

(more than just glimpses of micro- and macro-physics) 1 Motivation Introduction •Studying the sun, heliosphere, magnetosphere, ionosphere, mesosphere, FGSN 2 Contributions atmosphere, and climate change. Network Model Capacity Potential beneficiaries: Assessment •QB50, NPSCuL, MMC Projects Conclusion Future Work •NASA, Industry, DoD, Air Force Networks

•National Science Foundation (NSF) Image Credit: NSF Government News Website

•International CubeSat Community

(Michigan, CalPoly, etc) 1H. Spence and T. Moore. A retrospective look forward on constellation-class geospace missions. FallAGU Meeting, December 2009. 2T. Jorgensen. The nsf program: The promise of scientic projects. Fall AGU Meeting,December 2009. 4 March 2010 Contributions

1. Analytical model as a function of ground station and satellite Spangelo et al. constraints and mission requirements

Motivation Introduction 2. Assess network capacity and identify trends of existing and FGSN Contributions future networks by numeric simulation Network Model Capacity Assessment Conclusion Future Work Larger Goal: Develop robust, realtime optimization algorithms for multisatellite missions and FGSNs

5 March 2010 Network Capacity Model

Capacity: Amount of information exchanged across the network

Spangelo et al. m Capacity of Network: m = # Ground Stations CN = ∑C j (t) j=1 n = # Satellites Motivation T Introduction Capacity of Ground Station j: n FGSN C j = aij (t)rij ( )lt ij (t)ηij (t)dt Contributions ∑∫ i=1 Network Model 0 Capacity Assessment a: Availability Rate of data exchange Conclusion Future Work r:Data rate l: Link feasibility η: Efficiency T : Period

6 March 2010 Network Capacity Model

Ground Station Constraints: Antenna size Spangelo et al. Scheduling conflicts

Motivation Pointing/ slewing capabilities Introduction FGSN Contributions Network Model Capacity Satellite Constraints: Assessment Conclusion Antenna Size Future Work Transmit/ Receive Power Onboard energy storage Network Image Credit: NEC Microwave Tube, Ltd. Satellite Image Credit: Falling Pixel Website Pointing Capabilities 7 March 2010 Network Capacity Model Levels

Ellipse Area: Network Capacity, decreases with increasing model fidelity

Spangelo et al. Maximum Model Constant ideal Link

Motivation Introduction FGSN Topological Model Contributions Lineofsight Constraints Network Model Capacity Assessment Scheduled Model Conclusion Operational Constraints Future Work Actualized Model Offnominal Constraints

8 March 2010 Capacity Assessment: Tools

Tools Spangelo et al. • Satellite Tool Kit (STK)® and Matlab®

Motivation • Two line elements (TLEs) for Introduction FGSN Contributions from www.spacetrack.org Network Model Capacity • STK/SGP4 Propagator for orbit maneuver and trajectory analysis Assessment Conclusion • Models ideal PPOD deployment (V, plunger) Future Work • Computes separation, contact times

Image Credit: STK Website

9 March 2010 Capacity Assessment: Example Satellites and Ground Stations

CubeSats

• Spangelo et al. Low cost, standardized access to space •Miniaturized satellite (nanosatellite)

Motivation •Each Cube (1U): 10cm cube, 1 kg Example launcher: Poly Picosatellite Orbital Deployer (PPOD) standard Introduction interface between CubeSat and Launch Vehicle FGSN Radio Aurora Explorer (RAX) Contributions Network Model Capacity Ground Stations Assessment Conclusion Future Work

CubeSat Ground Station Community Air Force Satellite Control Network (AFSCN)

Images Credit: CalPoly Website, University of Michigan CubeSat Survey, US Air Force Portal Website 10 March 2010 Capacity Assessment

Average Daily Access Time Minutes/day Spangelo et al.

Motivation Introduction FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

11 March 2010 Capacity Assessment

Percentage coverage of Ground Stations

Spangelo et al. Satellite Inclinations Motivation Introduction FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

Percentage of satellite orbits the satellite will be in view of a ground station with minimum elevation 0 o. 12 March 2010 3 Ground Stations Capacity Assessment 1 Satellite

AeroCube-2 Satellite from Dneprt2 Launch Effect of Ground Station Latitude Orbital Parameters i- 98.04 o-98.08 o e = 0.0086 Spangelo et al. avg a = 7.085 ·10 3km

λ: Ground station latitude Motivation Introduction High latitude FGSN Contributions Network Model Capacity Mid latitude Assessment Conclusion Low latitude Future Work

3 Ground Stations in Air Force Satellite Control Network (AFSCN) to a AeroCube2 satellite in PPOD TacSat3 launch

13 March 2010 Capacity Assessment

Effect of Ground Station Latitude

Spangelo et al.

Motivation Introduction FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

Simulation of Satellite at 40 o Inclination using STK SPG4 Propagator

14 March 2010 6 Ground Stations Capacity Assessment 3 Satellites

Ground Station Latitude Category AFSCNSimulationsMultiple Availability (Topological Model)

AeroCube3, CP6, Hawksat Satellites (TacSat3 Launch)

i- 40.5 o

eavg = 0. 003 n = 15.4 rev/day a = 6.83km

Time after Epoch

43 days

15 March 2010 1 Ground Station Capacity Assessment 3 Satellites

AeroCube3, CP6, HawkAat Orbital Parameters Clustered Satellite PPOD Launch i- 40.5 o

eavg = 0. 003 Spangelo et al. a = 6.83 ·10 3km Individual and Total Network Capacity Separation of Satellite Pairs

TacSat3_sep.bmp Motivation Introduction FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

3 satellites from PPOD TacSat3 launch vehicle from I Ann Arbor Ground Station (Latitude: 42.27 N, Longitude: 83.74 W)

16 March 2010 15 Ground Stations Capacity Assessment 3 Satellites

AeroCube3, CP6, HawkAat Orbital Parameters Ground Station Network to 3 CubeSats i- 40.5 o

eavg = 0. 003 Spangelo et al. a = 6.83 ·10 3km

Motivation Introduction FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

Full Air Force Satellite Control Network to 3 Satellites in PPOD from TacSat3 launch vehicle from

17 March 2010 Future Work & Applications

Future Work:

CubeSat Survey to identify spacecraft needs Spangelo et al. Increase satellite and network model fidelity

Motivation Develop realtime scheduling tools International Ground Station Network Introduction FGSN Dynamic optimization techniques for mission design & tactical scheduling Contributions Network Model Capacity Future Applications: Assessment Conclusion CubeSat Developers (104 users, 98 GSs, 291 antenna systems) Future Work Naval Postgraduate School (NPS) NPSCuL to deploy 50 1U CubeSats

QB50 Project : 50 CubeSats science mission ( insitu and reentry research)

Image Credit: USGS NASA Website 18 March 2010 Acknowledgments

Spangelo et al.  Small Satellite Research Group

 Radio Aurora eXplorerQuestions? (RAX) Team Motivation Introduction  Professor McKague & CubeSat Community FGSN Contributions Network Model  National Science and Engineering Research Council of Canada (NSERC) Capacity Assessment  University of Michigan Aerospace Engineering Department Conclusion Future Work

19 March 2010 Spangelo et al. Questions? Motivation Introduction FGSN Contributions Network Model Capacity Assessment Conclusion Future Work

NASA’s First Deep-Space Internet

Photo Credit: NASA JPL Website 20 March 2010