Development, Deployment, Test & Operation of a Constellation of Microsatellites or Payloads for, Two-way Communication with, A Variety of Sensors Deployed Near or Below Surface of the Ocean Unattended Ground Sensors Sonobuoy Field International Space Station TacSat-X Host Spacecraft P-3 ASW UAV Space Segment for Global Autonomous Sensors Bob McCoy ONR Code 321SP Ocean Data Telemetry MicroSat Link (ODTML) Distributed Arrays of Small Instruments (DASI) Workshop 8 June 2004

Argo Profiling Floats  Operational Characteristics  Surface to 2,000 m  Salinity, Temperature and Pressure  Argos DCS Constraints:  Repeat Transmission every 60 to 72 seconds, hours every 10 days  Normally around 50 pressure levels (range 33 to 115)  Data 348 to 464 bytes (12 to 16 Argos messages)  $1.2 M “value-added” processing  Future Requirements  On Demand transmission 500 pressure levels (4 Kb) within one hour with reduced power demands for communications  Two-way communications (not necessarily on demand) for programming  $ K Target data telemetry cost

Over 3000 aircraft provide reports of pressure, winds and temperature during flight. Data Assimilation for Meteorological Forecast

Argos Data Collection System (DCS) in the NPOESS Era Argos Data Collection System (DCS) in the NPOESS Era

Iridium, GlobalStar & ORBCOMM  Existing ground-to-space/ground networking (Orbcomm, Iridium) were developed for voice and data, and rely heavily on fixed infrastructure, and power-intensive transmissions at VHF frequencies  ORBCOMM/Iridium are good for large littoral buoys where transmit power is not an issue and where L-Band attenuation (wave shadowing or microorganism growth) is not an issue  Current market (~20M/yr) is sufficient to sustain current systems but is insufficient to replenish the satellite constellation  Industry focus is not on low data-rate (<10,000 b/s) customers  Existing systems are not IP-like and require extensive groundstations and satellite monitoring  Operational Expense & Operations over the ocean

Ocean Data Telemetry MicroSat Communications Relay System Global Data Communications “On the Move” –Small, Mobile and Disadvantaged Platform Transceiver Terminals (PTTs) –Laptop Computers/Transceivers Availability –Robust RF Links – In Water and Under Cover Capacity –Many Users in the Field Service –Simultaneous Data Nets Assured Access –Acknowledgement That Messages Got Through Interoperability –Seamless Connectivity to Other Systems A Global Communications System Providing Near Real-Time Situational Awareness Is Essential for the Next Generation Ocean Observing System

Microsatellite Constellation Goals Demonstrate 2-Way communication with small disadvantaged sensors anywhere in the world –UHF transmission compatible with Service ARGOS, But with the following enhancements: -Significantly higher bandwidth (4800 b/s vs <256 b/s) -2-Way delay-tolerant communication -“IP-like” message packaging -New protocol for increased battery life & Non-GPS geolocation -Method to provide acknowledgement that command sequences were received (ACK/NACK) -Increased signal-to-noise at the host satellite via coding, a bi- directional software radio, similar to to forward messages to user/sensor with defined addressing schemes -Enhanced computer speed & storage for on-board data processing -System architecture allows evolution and expansion for future sensors -System capable of being deployed as a mix secondary payloads aboard host space vehicles (e.g. International Space Station, DMSP, TACSAT) or low-cost micro-satellites e.g., STP (Navy PG or USNA).

Multiple Access With Collision Avoidance by Invitation (MACA-BI) Network Protocol

GeoLocation Determination via Doppler Shift Spacecraft (S/C) Avionics Measure Doppler Shift on Uplink Carrier Frequency As S/C Approaches and Moves Away From Location of PTT At Point of Inflection of Doppler Curve (i.e., Rx vs. Tx Frequencies Are Equal), PTT Position Is Perpendicular to S/C Ground Track –Slope of Curve at Inflection Point Determines Distance From PTT to S/C Ground Track Location Errors of ~125m to 3000m (i.e, PTT Local Oscillator Stability, Number of Samples, and S/C Ephemeris Errors) Doppler Shift Metrology Sources of Location Location Errors Are Greatest When PTT Is ~170 km of the S/C Ground Track or More Than 2,700 km From S/C Ground Track Other Factors: –PTT Oscillator Stability – Mean PTT Short Term Frequency Stability <4x10E-5 (20 Minutes) –Mean PTT Frequency Must Not Vary > 24 Hz Between Multiple Passes (Two Overpasses) –PTT Altitude Creates Errors Due to Changes in Assumed Altitude (Sea Level) -Coupled in the “Across-Track” Coordinate of the Fix With Little Effect on the “Along- Track” Coordinates Spacecraft Requirements Location Determination Requires Ephemeris Within 300m (“Along- Track”) and 250m (“Across-Track”) Location Determination Requires >5 Doppler Measurements w/ >420 sec Interval Between First and Last Measurements w/ 240 sec Separation (Minimum Accuracy)

ODTML Key Performance Parameters

Communications Relay Payload Breadboard DC-DC Converters 3.3V, 5V, ±12V 24VDC Input Motor Drive Interfaces (0 Populated) Linear Regulators 2.5V, ±5V Analog Expansion Interface (0 Populated) Expansion Interfaces 0 Populated) Expansion Interface (0 Populated) RS232 Interface RS422 Interface LVDS Interface EEPROM PROM XILINX Virtex400 FPGA Local SRAM Shared SRAM Configurator 1553 Interface Discrete I/O Expansion Interface MCU RS232 Actel 54SXnn FPGA

ODTML MicroSat Configuration Simple Design and Interfaces Enable Ease of Development and Integration Payload Minimum Resources Available: ~25 Watts Orbital Average Power (OAP) - Basic ~5 kg Mass (Basic) 0.3m x 0.75m x 0.8m Size 350 b/s Average Payload Stored Data b/s Payload Housekeeping Stored Data Thermally Stable With Constant Dark and Sun Sides ODTML Payload Provides Uplink/Downlink Communications Body Mounted GaAs Solar Arrays: Allows Common Satellite Design for All Orbit Planes Minimizes Body Drag Perturbations on Gravity Gradient (G-G) Stabilizing Torques Improves Reliability Reduces Cost and Simplifies Integration Communications Relay Transceiver Communications Relay Processor Hydrazine Propulsion System Magnetic Torque Rods Three Axis Magnetometer Spacecraft Avionics (Includes 3 Micro Gyros) Lithium Ion Battery Spacecraft Structure Heritage LightBand Separation

Low Cost Communications Gateway Uses Same Electronics Suite As Buoy System Characteristics UHF Eggbeater Antenna –Omni-Directional –Circular Polarization (RHCP) Communications Relay Payload Repackaged for Ground Environment Plus High Power Amplifier (HPA) Laptop Interface (Portable Ops) OR PC-Based Mail Server and Remote Intelligent Monitoring System (RIMS) for Fixed Gateway

Potential Launch Opportunities Low-cost launch opportunities: Alternate Launch Vehicles –EELV Secondary Launch -4 tons excess for each DMSP launch –SpaceEx Falcon - TacSat follow-on University MicroSat Designs –CubeSat –ASTRID/MUNIN –USNA PC Sat Cubesat EELV SpaceEx Falcon CubeSat ChipSat MUNIN PC Sat

TacSat-1 Program Elements Navy Highlights GROUND STATION: Blossom Point MD –Navy Facility –With VMOC (Virtual Mission Operations Center) for SIPRNET Tasking & Data Dissemination MICROSATELLITE: –1 yr Life, 110kg, 186W –40in dia. x 20in high –500km, 64º inc. AIRCRAFT: –EP-3’s: 1 Fixed & 3 Mobile RORO Units; Also RJ’s (TBD #) Expected –Implementing an Naval, ONR Cross-Mission CONOP LAUNCH VEHICLE: Falcon by SpaceX –New, Privately Developed –LOX-RP1 gives ~1000 lb to 500km –60klb, 70ft by 5.5ft dia. –Navy Contract PAYLOADS: –CopperField-2S: Navy TENCAP –SEI: NRL/ONR? Developed –Visible & IR Cameras (Army NVL) $12M $3M

IR Camera & UHF Radio SEI Hermetically Sealed Chassis (CuF-2S is Similar) Rubidium Clock & Low Cost Receivers (0.5-18GHz Range Used) TacSat-1 Spacecraft Components Specific Emitter Identification (UYX-4) & Copperfield-2S Payload Hardware Spacecraft Bus & EAGE Hardware CURRENT Technology by COMPUTER INDUSTRY STANDARDS (3 Million Gate FPGA) Receivers Clock UYX-4 Fans 2 Places IR Camera Does NOT Require Cryo-Cooling

Program Plan Build satellite/aircraft payload and test via aircraft flight(s) (2005) Orbital test using existing orbital UHF satellite (2005) –(10kg NanoSat; half duplex mode – SpaceQuest) Deliver satellite payload on International Space Station (2006) –57º Inclination (via Space Test Program) Launch polar payload/satellite (2007) on TacSat-n, DMSP or STP payload of opportunity Test ocean to space system with realistic RF & ocean environment –Communication links with actual Doppler –Distance fading –Actual environment (shadow fading - wave height) –Operate autonomously, unattended

6-8 Hrs Revisit time Sp International Space Station Tac-Sat n Near Term 2 Planes Ultimate goal 6 Satellites in 3 Planes 2.5 Hr revisit

Operational CapabilityConcept of Operation Ocean Data Telemetry MicroSat Link (ODTML) Communications Relay Payload to Support an Integrated Global Ocean Observing System via MicroSat or Host Platform Data Infiltration and Exfiltration for Small, Mobile, and Low- Power Ocean Buoys and Sensor Transceiver Nodes Two-Way, Delay-Tolerant, “Internet-Like” Messaging Services on Global or Theater Basis Allows Users to Send Commands and Receive Telemetry From Autonomous Buoys or Distributed Sensor Nodes Decouples Nodes From Space Segment Allowing Evolutionary Upgrades or Expansion of Capabilities Higher Bandwidth, Lower Power Than Existing Service Argos > 50 Kilobits Per Node Per Day < 0.1 Joule Per Bit Transmitted Two-Way Global Communication to Provide Near Real-Time Awareness Is Essential for Next Generation Ocean Observing Systems Phase I – Lab Demonstration Completed Phase II – Non-Flight Engineering Unit (6/04 ONR SBIR Funds) 6/04 – 6/06 System, H/W & S/W Designs/Demos 1/06 – 12/06 Engineering Unit Build, Integration & Test 1/07 – 3/07 Field Demonstrations Requesting Official: Dr. C. Luther, ONR, Phase II Sponsor: Dr. R. McCoy, ONR, ONR Small Business Innovation Research (SBIR) Topic N (ODTML) DOD Space Exp Review Board (SERB) ONR-0301 (Ranked Experiment) Global Data Collection System Architecture via “Ad- Hoc Wireless Networking” and “Instant Messaging” “Router in the Sky” via MicroSat or Aircraft Host Technical Approach Enabling Technology Flight-Proven FPGAs, Router and Cellphone Concepts, and Low-Cost On-Orbit Commercial MicroSats (Spacequest / Aprize, Ltd) Schedule & Budget Praxis, Inc., 2200 Mill Road, Alexandria, VA Mr. R. Jack Chapman, Principal Investigator , Contact