GPS Radio Occultation Hosted Payload on Iridium NEXT

Fourth COSMIC Data Users Workshop, Boulder CO

October 29th, 2009

Dr. Om P Gupta

Iridium Communications Inc.

Om.Gupta@iridium.com

Iridium Communications Inc.• Transaction with Greenhill completed in September, 2009.

Iridium Communications Inc is listed on NASDAQ (Ticker Symbol: IRDM)

• Satellite voice and data solutions for enterprise & government

• The only provider offering 100% worldwide coverage

• ~347,000 subscribers(1)

• Anchor U.S. DoD customer – 23% of 1H09 revenue(2)

• Iridium network complements terrestrial wireless solutions

• Most of the earth’s surface is not served by terrestrial wireless systems

• Expanding portfolio of products & services sold via a broad distribution network

• Data services growing rapidly

• Unique, resilient mesh satellite architecture - 66 LEOs & 7 in-orbit spares

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(1) At 6/30/09(2) Includes direct and indirect DoD revenues and revenues from certain other governmental entities through the DoD gateway

NEXT Constellation• Iridium NEXT (NEXT) is planned to replace current

satellite fleet starting in 2014

• Final NEXT launch completed by end of 2016

• Current fleet is expected to provide commercially acceptable service through transition to NEXT

• NEXT is planned as a constellation of 66 cross-linked LEO satellites and 6 spares

• Maintains Iridium’s unique architecture:

• True global coverage, low latency, providing real time transmission of data from anywhere on Earth

• Compatibility with current fleet eases network transition

• NEXT advantages:

• Higher data rates up to 1.5 Mbps (L-Band), ~10 Mbps Ka Band service, and other new services

• Designed to host secondary payloads

• Expands capacity to 3 MM plus subscribers

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Constellation 66 SVs in 6 planesOrbit Polar at 780 kmInclination 86.4o

Period 101 min per orbit

Hosted Payload Opportunity on NEXT• Hosted payloads missions deployed on NEXT provide following key benefits:

• One-of-a-kind solution for entities seeking global coverage/data from remote sensors and earth/climate observation instruments hosted on NEXT satellites

• Unprecedented spatial and temporal coverage with 66 hosted payloads

• Real-time data transmission from hosted payload in space to a user on ground

• Cost-effective – A fraction of the cost of dedicated satellites using Public-Private Partnership (PPP)

• Possibility of longer mission life for hosted payload, through 8-10 year satellite design life of SVs; and long term mission continuity; SV replenishment and follow-on constellations are needed for business reasons offering future opportunities for additional hosted payload deployments

• Significant interest from government bodies, international agencies and industry in sharing NEXT global networked communications infrastructure

• Iridium and its team of expert partners have completed several technical feasibility studies of possible missions including GPSRO, Altimetry, ERB, Ocean Color, Solar Irradiance, and more, demonstrating compatibility with NEXT

• Window of Opportunity to commit to hosted payload on NEXT extends till the PDR planned for in 2011

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Specifications

Weight 50 kg

Payload Dimensions 30 x 40 x 70 cm

Payload Power 50 W average (200 W peak)

PayloadData Rate <1 Mbps

Iridium NEXT Hosted Payloads Specifications

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2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Iridium NEXT Hosted PayloadsDecision Time Line

SYSTEM CONTROL, TELEPORT NETWORK & GATEWAY EVOLUTION

SUBSCRIBER DEVELOPMENT

LAUNCH VEHICLE PROCUREMENT & EXECUTION

REQUIREMENTS

SYSTEM DEVELOPMENT

SV QUALIFICATION

LRIP FRP & LAUNCH

RFI SRR PDR PRR IOC FOC

FirstLaunch

OptimumProgram

Start Date

Hosted Payload Interface

Specification Released

Hosted Payload Interface

Specification Finalized

Feasible Study Window

Mission Decision Window

Hosted Payload Selection, I&T, Qual Test, Integration with SV, Launch

Mission Launch Window

NEXT

HOSTED

PAYLOADS

Iridium Proprietary and Confidential

CDR

Optimum program start by PDR in 2011 to meet first launch window Flexibility declines with CDR in 2012

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GPSRO Mission on NEXT – Feasibility Study

• A detailed feasibility study has been completed for GPSRO mission, consisting of sensor surveys, sensor design trades, optimum orbital configuration and NEXT accommodation analysis

• GPSRO RF Interference between GPS L1 and Iridium L-band transmit was considered a key issue, and it has been studied in detail and solutions established

• A solution using 12 GPSRO sensors (GPS/Galileo) on NEXT was demonstrated as providing an optimal data set for measuring global atmospheric temperature and humidity profiles in REAL TIME• Over 14,000 soundings per day possible with 12 sensors• Using these GPSRO sensors, electron content of ionosphere & density profiles

measurements for space weather application is also possible in REAL TIME

• NEXT GPSRO solution would enable real-time input to weather models, and ability to grow the amount of data input over time

• Target Applications include• Tracking extreme weather events• Weather now-casting and forecasting• Seasonal variations; climate variability; hydrologic cycle

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Survey of GPSRO Receivers• Broad Reach Engineering

• Pyxis RO• Based on IGOR/JPL Blackjack development• IGOR has long history in RO

• GRACE, SAC-C, CHAMP• Most recently flown on FORMOSAT-3 and COSMIC

• Thales Alenia Space• Topstar RO

• Based on Topstar 3000 G2 satellite navigation GPS receiver• Low cost receiver with only one POD and one RO antenna

• ROSA NG• Based on LAGRANGE and Topstar 3000 GPS navigation

receiver• ROSA developed for Italian Space Agency

• RUAG• GRAS-2

• Based on GRAS RO mission launched on ESA’s MetOp-1• GRAS-2 to have reduced size, power, smaller RO antennas

than GRAS

Pyxis

IGOR

TOPSTAR 3000 G2

ROSA

GRAS

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Interface with NEXT SV

• GPSRO sensor assemblies consisting of the following were studied

• Receivers

• One or two RO antennas in +/- velocity directions

• One or two POD antennas 60 degrees off Zenith

• Iridium NEXT design enables accommodation of the GPSRO antenna and all associated electronics

• GPSRO sensor mass is relatively small compared to 50 Kg limit, which makes it possible to host

• Additional secondary payload missions on the same SV provided total mass and data rate constraints for the combined missions are met

• For example, GPSRO mission may be combined with Altimetry, ERB, or and Ocean Color on the same SV

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Sensor Quantity and Capability

• Study established that sensors on more satellites will produce more evenly distributed geographic coverage than more RO antennas

• 24 satellites provide more even distribution than twelve over a shorter period of time

• Technically, 24 satellites with only one aft-looking RO antenna are marginally better

• Analysis also included GPS and GPS/Galileo options

Twelve dual RO antenna sensors capable of receiving GPS and Galileo signals for RO provide optimum results

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Sensors on 12 Satellites - Occultation

12 Sensors on NEXT, 24 hours, GPS and Galileo14,250 Occultation

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• This work carried out by Iridium/Lockheed team to study a potential RF interference issue between GPS L1 and Iridium L-band

• A conceptual but detailed analysis has established that, under worst operating conditions, this interference can be mitigated for 99.7% of duration in 2016, dropping to 99.2% of duration in 2025

• Multiple methods were identified that can contribute to mitigating this interference, but in this analysis only a few were needed

• Others can be explored during actual implementation phase of a GPSRO mission on NEXT to achieve an optimum performance

GPSRO RF Interference Analysis

Lockheed Martin Space Systems Company Copyright © 2009 12

• GPS RO L1 measurements are expected to have an excellent probability of success on Iridium NEXT SV

• Establishing low noise in GPS L1-band is key; • L2, L5 GPS bands are separated much more in frequency than L1 is from Iridium

NEXT; noise situation should be better farther away

• Certain design criteria need to be met for success, some features already inherent to the SV structure and GPS receivers• Factors with positive impact:

• High isolation (~48 dB) from physical spacing between MMA and GPS RO antennas• GPS spread spectrum operation: inherently anti-jam• Broad band noise is the least effective of all jammers • Low MMA noise level from higher order inter-modulation products

• Favorable results were obtained in comparing Iridium NEXT noise level to criteria from various sources• JPL noise floor prediction• Stanford tests for GPS accuracy impairment• NTIA tests for GPS impairment• China Lake tests for GPS jamming susceptibility

GPSRO RF Interference Analysis Summary

Lockheed Martin Space Systems Company Copyright © 2009 13

Concept of Operations and Data Handling• Iridium Operations manages deployment and operation of the Iridium System

• Enables sensor command and data path to an MPLS cloud• Has the capability to turn off the sensor to preserve the Iridium mission

• Sensor Operations manages sensor including:• Sensor targeting and model updates• Updating software or firmware• Data stream management (pull or push from the MPLS cloud)• Anomaly resolution

• Data Processing Center receives data stream from MPLS cloud and processes the data for End Users

• End Users receive Level 2 and 3 data and provide feedback to Sensor Operations and Data Processing

IRIDIUM MPLS DATA END USERSEO INTERFACE CLOUD PROCESSING CENTER

LEVEL 0 LEVEL1 LEVEL 2&3

SPACE AND GROUND SEGMENT

Sensor Ops

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Occultation Simulation – 12 Sensors 15

Summary

• Detailed studies have been performed on GPSRO to establish technical feasibility

• GPSRO mission is an excellent fit with NEXT; provides excellent data distribution, real-time communications and cost effectiveness

• Space Weather mission is also enabled with low latency and global coverage to cover all regions of interest

• Hosted payload on Iridium NEXT is moving forward

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Unique Opportunity for Earth Observation through 66 hosted payloads on NEXT supplying data in REAL TIME from anywhere on Earth

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THANKSContact:

Dr. Om P GuptaIridium Communications Inc.

6707 Democracy Blvd, Suite 300Bethesda MD 20817 USA

o: +1.301.571.6229 c: +1.443.812.9724 www.iridium.com