Space Environment Impacts on Geosta2onary Communica2ons Satellites

Transcription

1 Space Environment Impacts on Geosta2onary Communica2ons Satellites Thesis Proposal Defense Whitney Q. Lohmeyer Chair: Kerri Cahoy May 6, 2013

2 Military COMSAT aler Environmental Tes2ng [1] 2

3 Problem Statement Objec2ves Research Ques2ons Outline Free Space Path Loss Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec2on Algorithm Plan for Progression 3

4 Problem Statement In 2008, the NRC hosted a workshop Societal & Economical Impacts of Space Weather [2] >250 communica2ons satellites (COMSATs) $75 billion investment and $25 billion revenue SW is a constant, on- going problem At GEO, SW drives design redundancy To quan2fy how space weather effects COMSAT performance Must have both space weather (SW) data and satellite telemetry Obtaining satellite telemetry is difficult! 4

5 Objec2ves Team with two COMSAT companies Inmarsat (London, UK) & Telenor (Norway) Analyze >1 million hours of opera2onal telemetry 8 Inmarsat GEO satellites (2 unique fleets) 4 Telenor GEO satellites (4 unique bus designs) To answer three primary research ques2ons Inmarsat4 F1 Satellite [3] Thor 7 [4] 5

6 Research Ques2ons 1. What are the future planned capabili2es and design trends for GEO COMSAT - How are satellite components, specifically power amplifiers evolving with these trends? 2. How does SW affect current GEO COMSAT components - In terms of low- energy electrons, the Kp index, high- energy protons and electrons, and galac2c cosmic rays 3. Can we use GEO COMSAT telemetry to understand more about SW phenomena in general and not just at the 2me of the anomaly? - Analy2cal tools (sta2s2cs, FT - traffic analysis, deriva2ves) 6

7 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec2on Algorithm Plan for Progression 7

8 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta-onary Communica-on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec2on Algorithm Plan for Progression 8

9 1. Trends in GEO COMSATs COMSATs represent the most important applica2on of commercial satellites today Capabili2es are growing to accommodate high demands of informa2on distribu2on [5] Higher data rates, higher band width, smaller components, increased power and efficiency, etc. Amplifiers consume ~85% of satellite power [6,7] Control satellite performance Amplifiers are the component of focus for the trend analysis 1960 Echo 1 [18] 2013 Inmarsat I5 [19] 9

10 What are power amplifiers? Key components in satellite comm systems Strengthen uplink signals that are weakened from free space path loss [6,8,9] Amplifier units consume ~85% of the spacecral bus power [6,7] Free Space Path Loss Two primary types: solid state power amplifiers (SSPAs) and traveling wave tube amplifiers (TWTAs) Technologies experienced rapid change over past decades 10

11 TWTAs vs. SSPAs TWTA Technology Traveling wave tube (TWT) and electrical power condi2oner (EPC) Used for high power + high freq. Provide be@er efficiency [10] % COMSATS used TWTAS [11] SSPA Technology Field effect transistor (FET) and EPC [6] More reliable and safe Less complex and cheaper [13,14] Historically used at L + S band Compe22ve in 1980s, new GaN technology is increasing market popularity [9] TWTA [12] SSPA [16] 11

12 Historic SSPA vs. TWTA Studies [6,16] European Space and Technology Center (ESTEC) 1993 NASA Lewis 2005 Boeing 75 satellites / 11 operators >463 years of satellite opera2on TWTAs (1765 C- and Ku- band) and SSPAs (309 C- band) TWTAs more reliable (790 FITS SSPA and 680 FITS TWTA) 6/5 TWTA redundancy 3/2 SSPA Redundancy 72 satellites >497 years of satellite opera2on TWTAs (855 C- and Ku- band) and 365 (C- band) TWTAs 1/3 more reliable than SSPAs Failure rates increased by 8% at Ku- band Similar RF output levels SSPAs use for W, TWTA used for W >100 satellites >12600 years of amplifier opera2on TWTAs (1783 Ku- band) SSPAs (944 C- band) FITS on TWTAS less than SSPAs No reliability diff. Explored failure mechanisms 9 % satellites had 2 SSPA failures SSPAs 66W less RF output than TWTAs 12

13 TWTA vs. SSPA Study Our Extension What are the future planned capabili2es and design trends for GEO COMSAT? - How are satellite components, specifically power amplifiers evolving with these trends? Approach: Analyze >150 years (>1 million hours) of amplifier data >450 SSPAs (Inmarsat) and ~100 TWTAS (Telenor) Define the current amplifier capabili2es Compare technologies Reliability (number of failures) Failure mechanisms (SW related?) Hardware characteris2cs size, mass, cost (if possible) 13

14 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec2on Algorithm Plan for Progression 14

15 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada-on Anomalous Component Detec2on Algorithm Plan for Progression 15

16 2. Study of Known Satellite Component Anomalies How does SW affect current GEO COMSAT components? Inves2gate rela2onship of anomalies and Low- energy electrons: Kp index High- energy electrons: ~2 MeV electron flux High- energy protons: 10 and 30 MeV proton flux Galac2c Cosmic Rays: cosmic ray intensity (CRI) Local Time Index Inves2gate rela2onship of solar array degrada2on and High- energy protons: 10 and 30 MeV proton flux Galac2c Cosmic Rays: cosmic ray intensity (CRI) SSPA [16] Solar Panels [4] 16

17 Acquiring Data Space Weather Data and Communica2ons Satellite Data Geostationary Operational Environment Satellite [8] (GOES) 2 MeV Electron Flux 30 MeV Proton Flux OMNI2 Database Kp Index Sunspot Number Magnetic Field Components (Bz) Solar Wind Speed 10 and 30 MeV Proton Flux Los Alamos National Labs (LANL) Data MeV Electron Flux Inmarsat SSPA Current SSPA Temp Solar Array Current and Voltage Total Bus Power Single Event Upsets Anomaly Log Telenor TWTA Current TWTA Temp Solar Array Power Anomaly Log 17

18 Current Findings SW Effects on Inmarsat Anomalies Twenty- six SSPA anomalies between Fleet A anomalies occur in declining phase of solar cycle Enhanced electron flux 11/26 anomalies occur 1-2 weeks aler enhanced electron flux No obvious rela2onship with Kp, proton flux, or local 2me The Space Environment [16] 18

19 Fleet A SSPA Anomalies + Solar Cycle 19

20 SSPA Anomalies and High Energy Electron Flux 20

21 Local Time of SSPA Anomalies 21

22 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec2on Algorithm Plan for Progression 22

23 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec-on Algorithm Plan for Progression 23

24 3. Anomalous Component Detec2on Algorithm Can we use GEO COMSAT telemetry to understand more about SW phenomena in general and not just at the 2me of the anomaly? Anomalous SSPA Opera2on Devia2ons in seasonal averaged (3- month) SSPA current data 24

25 3. Anomalous Component Detec2on Algorithm Import temporal telemetry data each parameter (SSPA current, solar array voltage, etc.) and 2me stamp Incorporate analy2cal tools Periodic Analysis: Fourier transform Differen2al Analysis: Deriva2ve (understand when telemetry changes slope) Matching: compare structure of telemetry over specified periods Sta2s2cal Analysis: running averages, standard devia2ons, etc. Traffic Analysis 25

26 Outline Problem Statement Objec2ves Research Ques2ons Trends in Geosta2onary Communica2on Satellite (GEO COMSAT) Design Study of Known Component Amplifiers and Solar Array Degrada2on Anomalous Component Detec2on Algorithm Plan for Progression 26

27 Major Goals and Upcoming Milestones May 2013: Present SW analysis at SPENVIS Conference June 2013: Present lecture on Geomagne2c Storms GEM Workshop 2013 June 2013: Space Weather Enterprise Forum April 2013: Publish Inmarsat results in AGU Space Weather Journal: submi8ed August 2013: Finish gathering telemetry for study Ac2vely engaged with two (poten2ally three) other operators Feb May 2015: Conduct analysis/write disserta2on May 2015: Defend thesis 27

28 Plan for Future Work 1. SSPA vs. TWTA Trends Finish obtaining telemetry data Define capabili2es and failure mechanisms 2. Known Component Analysis Organize all telemetry data Determine rela2onship of anomalies/degrada2on and defined phenomena (electrons, protons, GCRs) 3. Anomalous Component Detec2on Algorithm Determine telemetry input structure Incorporate analy2cal tools (sta2s2cal, periodic, differen2al, etc.) 28

29 References [1] Military COMSAT image - h@p:// second- aehf- comm- sat- completes- major- environmental- test- at- lockheed.aspx [2] Severe Space Weather Events Understanding Societal and Economic Impacts Workshop Na9onal Research Council. Na2onal Academy of Sciences. <h@p:// html>. [3] Inmarsat 4 Picture h@p://space.skyrocket.de/doc_sdat/inmarsat- 4.html [4] Thor7 Imageh@p:// [5] Aloisio et al. (2010), R&D Challenges for Broadband Satcomms in 2020, 1EEE Interna2onal Vacuum Electronics Conference, May [6] Strauss, R. (1993), Orbital Performance of Communica2on Satellite Microwave Power Amplifiers (MPAs), Interna9onal Journal of Satellite Communica9ons, 11, [7] Illoken, E. (1987), TWT Reliability in Space, Aerospace and Electronic Systems Magazine, IEEE, 2(7), [8] Robbins et al. (2005), Performance and reliability advances in TWTA high power amplifiers for communica2ons satellites. In Military Communica9ons Conference, MilCOM 2005, [9] Kaliski, M. (2009), Evalu2on of the Net Steps in Satellite High Power Amplifier Technology: Flexible TWTAs and GaN SSPAs, IEEE Interna2onal Vacuum Electronics Conference, April

30 References [10] Komm et al., (2001), Advances in Space TWT Efficiencies, IEEE Transac9ons on Electron Devices, 48(1). [11] Mallon, K.P. (2008), PL.6: TWTAs for Satellite Communica2ons: Past, Present and Future, IEEE, [12] TWTA Image www2.jpl.nasa.gov [13] Escalera, N., (2008), Ka- band, 30 solid state power amplifier. In Microwave Symposium Digest IEEE MTT- S Interna9onal (Vol. 1, pp ), IEEE. [14] Sechi, F., and M. Buja{ (2009), Solid- State Microwave High- power Amplifiers. Artech House, M.A. [15] SSPA Image h@p:// band- sspa.html. [16] Strauss, R. (1994), Reliability of SSPA s and TWTA s, IEEE Transac9ons on Electron Devices, 41(4), [17] Space Environment Image sohowww.nascom.nasa.gov/spaceweather/. [18] Echo 1 image h@p:// - communica2on - satellite- giant- space- balloon- 50- years.htm [19] Inmarsat 5 image space.skyrocket.de [20] Electromagne2c Energy Spectrum Image donsnotes.com/tech/em- spectrum.html 30

31 Back- Up Slides 31

32 32

33 SSPA vs. TWTA Historical Trends [6,11] TWTA Technology First successful RF amplifier for COMSATS 1960 From , RF output capability increased 1000% for 4 (S), 12 (X), and 20 (K) GHz 1990 TWTAs were capable of ~50% efficiency, Ku band 50 W 2005 TWTAs opera2ng across L- Ka band with W RF output, some specified for up to 250W at 60% efficiency 2012 L- band 65%, 140W (3x efficiency of SSPA at 2me) SSPA Technology SSPAs introduced in 1970s for space applica2ons compe22ve in 1980s (amplifier of choice) 1990s SSPAs were capable of ~35% efficiency, used for 20-40W despite low efficiencies 2000 SSPAs opera2ng in low frequency bands (L, S, and C) with output RF of 30 W, highest Ka- band SSPA 30 W with 20% efficiency 33

34 Previous Contribu2ons April 2012: Space Weather Workshop presented ini2al Inmarsat work September 2012: AIAA Interna2onal Communica2ons Satellite Systems Conference (ICSSC) presented Inmarsat analysis March 2013: IEEE Aerospace presented Inmarsat SEU and SEP Analysis 34