Iridium Communications (IRDM) DEFA14A Additional proxy soliciting materials

Exhibit 99.1

Iridium Enters the Public Markets via Combination with GHL Acquisition Corp. September 2008 GHL Acquisition Corp.

Forward Looking Statements This communication contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The words "anticipates", "may", "can", "believes", "expects", "projects", "intends", "likely", "will", "to be" and other expressions that are predictions of or indicate future events, trends or prospects and which do not relate to historical matters identify forward-looking statements. These forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the actual results, performance or achievements of GHL Acquisition Corp. ("GHQ") and/or Iridium Holdings LLC ("Iridium") to differ materially from any future results, performance or achievements expressed or implied by such forward-looking statements. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. These risks and uncertainties include, but are not limited to, uncertainties regarding the timing of the proposed transaction with Iridium, whether the transaction will be approved by GHQ's stockholders, whether the closing conditions will be satisfied (including receipt of regulatory approvals), as well as industry and economic conditions, competitive, legal, governmental and technological factors. There is no assurance that GHQ's or Iridium's expectations will be realized. If one or more of these risks or uncertainties materialize, or if our underlying assumptions prove incorrect, actual results may vary materially from those expected, estimated or projected. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. Except for our ongoing obligations to disclose material information under the Federal securities laws, we undertake no obligation to release publicly any revisions to any forward-looking statements, to report events or to report the occurrence of unanticipated events. GHL Acquisition Corp. 2

Additional Information and Where to Find It This communication is being made with respect to a proposed acquisition and related transactions involving GHQ and Iridium. In connection with these proposed transactions, GHQ intends to file with the Securities Exchange Commission ("SEC") a preliminary proxy statement and to mail a definitive proxy statement and other relevant documents to GHQ's stockholders. The information contained in this communication is not complete and may be changed. Before making any voting or investment decisions, GHQ's stockholders and other interested persons are urged to read, when it becomes available, GHQ's preliminary proxy statement, and any amendments thereto, and the definitive proxy statement in connection with GHQ's solicitation of proxies for the special meeting to be held to approve the acquisition and any other relevant documents filed with the SEC because they will contain important information about Iridium, GHQ and the proposed transactions. The definitive proxy statement will be mailed to GHQ stockholders as of a record date to be established for voting on the proposed acquisition. Stockholders and other interested persons will also be able to obtain a copy of the preliminary and definitive proxy statements once they are available, without charge, at the SEC's web site at http://www.sec.gov or by directing a request to: GHL Acquisition Corp., 300 Park Avenue, 23rd Floor, New York, New York, telephone: (212) 372-4180. GHQ also intends to launch a tender offer for its common shares which tender offer will be expected to close concurrent with the closing of the acquisition of Iridium. The tender has not yet commenced. This communication is neither an offer to purchase nor a solicitation of an offer to sell shares of GHQ. Upon commencement of the tender offer, GHQ will file with the SEC a tender offer statement on Schedule TO and related exhibits, including the offer to purchase, letter of transmittal and other related documents. GHQ stockholders and other investors should read these materials carefully when such documents are filed and become available, as they will contain important information about the terms and conditions of the tender offer. Stockholders and other interested persons will also be able to obtain these documents once they are available, without charge, at the SEC's website at http://www.sec.gov, or by directing a request to : GHL Acquisition Corp., 300 Park Avenue, 23rd Floor, New York, New York, telephone: (212) 372- 4180. GHL Acquisition Corp. 3

Participants in the Solicitation GHQ and its directors and officers may be deemed to be participants in the solicitation of proxies to GHQ's stockholders in connection with the acquisition. A list of the names of those directors and officers and a description of their interests in GHQ is contained in GHQ's report on Form 10-K for the fiscal year ended December 31, 2007, which is filed with the SEC, and will also be contained in GHQ's proxy statement when it becomes available. GHQ's stockholders may obtain additional information about the direct and indirect interests of the participants in the acquisition, by security holdings or otherwise, by reading GHQ's proxy statement and other materials to be filed with the SEC when such information becomes available. Nothing in this communication should be construed as, or is intended to be, a solicitation for or an offer to provide investment advisory services. GHL Acquisition Corp. 4

Table of Contents 1. Transaction Overview 2. Overview of Iridium GHL Acquisition Corp. 5

Iridium Enters the Public Markets o Iridium to become a NASDAQ-listed company through a reverse acquisition transaction with GHL Acquisition Corp. ("GHQ") o Iridium owns and operates the world's largest and most sophisticated commercial satellite network f Provides global communications between people, vehicles, aircraft, vessels, assets > More than 305,000 end-user subscribers globally, growing rapidly > Strong revenue and EBITDA growth o Iridium sees significant benefits to becoming a public company > More efficient access to capital > Greater visibility and credibility with customers and suppliers > Potential acquisition currency > Enhanced ability to attract, retain and motivate world-class talent GHL Acquisition Corp. 6

Merits of the Transaction The transaction will enhance value by allowing Iridium to emerge as a public company with no net debt, ready to fund continuing growth o High quality business > One of only two major players in the sector (Inmarsat the other) > Only provider with truly global service > US Department of Defense serves as long-term anchor customer > Valuable, global spectrum holdings > Satellite operations outsourced to Boeing o Substantial scale > $107 million Operational EBITDA(1) based on first half 2008 annualized o Rapid growth > 5 separate subscriber verticals, all growing > First half Operational EBITDA(1) up 55% versus prior year o Attractive valuation > 7.5x trailing Operational EBITDA(1) based on annualized first half results (fully-distributed value, pro forma for transaction and GHQ warrants) > Inmarsat trading at 14.8x annualized first half 2008 EBITDA o Valuation enhancement potential > New products and applications > Brand enhancement from net debt-free balance sheet and public company status Note: 7 (1) Operational EBITDA excludes revenue and expenses associated with next generation constellation deployment that cannot be capitalized. GHL Acquisition Corp. 7

Iridium has been and continues to be on an impressive growth trajectory, recently experiencing some of the strongest months of operation in its history Transaction Overview Strong and Consistent Growth o Significant Long-Term and Recent Growth in Subscribers > Currently more than 305,000 subscribers > 32% compound annual growth 2002-2007 > 38% growth June 2008 vs. June 2007 > May and June of 2008 each set new records for subscriber additions o Significant Long-Term and Recent Growth in Revenue > 31% compound annual growth 2002-2007 > 31% growth first half 2008 vs. first half 2007 o Significant Long-Term and Recent Growth in Operational EBITDA (1) > EBITDA positive since 2004 > 55% growth first half 2008 vs. first half 2007 > At inflection point with largely fixed cost business model o Strong Performance Across All Verticals > Maritime > Aviation > Government > Land/Mobile (Handsets) > Machine-to-Machine (Asset Tracking and Telemetry - Short Burst Data) Note: 8 (1) Operational EBITDA excludes revenue and expenses associated with next generation constellation deployment that cannot be capitalized. GHL Acquisition Corp. 8

The value of the deal is enhanced by a variety of structural points Transaction Overview Structural Transaction Enhancements Minimal cash paid to Iridium shareholders Existing owners want to maintain significant ownership going forward Cash retained enables Company to be debt free and fund future growth Tender offer to buy up to 30% of GHQ shares at a premium, which will close concurrent with the transaction Step up in tax basis of Iridium's assets resulting from transaction creates substantial future tax savings Future warrant proceeds help fund next generation of satellites Substantially reduced economics to GHQ sponsor f Both sponsor shares and warrants reduced significantly Greenhill & Co. ("Greenhill") investing an additional $22.9 million in Iridium in separate transaction pre-closing GHL Acquisition Corp. 9

Transaction Overview Iridium Benefits from Greenhill Sponsorship Why is Iridium entering the public markets through a reverse acquisition with GHQ? GHQ Represents a Unique Sponsor Sponsorship enhances appeal to prospective customers Greenhill telecom expertise and advice Greenhill investing track record generally and within the telecom space Long history of Greenhill public-company stewardship Greenhill expertise in issues inherent in transitioning high-quality organizations to public ownership Efficient and Accelerated Approach to Entering Public Markets Limits management distraction or business disruption Alignment of Interests $20.0 million Greenhill/staff investment in GHQ $22.9 million additional investment by Greenhill in Iridium prior to acquisition GHL Acquisition Corp. 10

Transaction Overview Greenhill believes Iridium shares a number of important attributes with its successful investment in Global Signal Greenhill, through its investment funds, initially invested in Global Signal (then named Pinnacle Holdings) in 2002 and generated an 8.0x blended return on its capital Greenhill Relevant Investment Experience Global Signal - Many Common Attributes with Iridium Strong subscriber growth, Strong subscriber growth, Secular increasing coverage needs, new increasing coverage needs, new Growth applications driving demand applications driving demand Strategic, high quality cell tower Low latency, high call quality Superior locations nationwide satellites providing truly global Product coverage Significantly overleveraged Globalstar network issues; no other Impaired competitors unable to compete "fully global" competitor Competition effectively Difficult zoning and approval for any Difficult to acquire spectrum, orbital Barriers to new cell towers space, VAR relationships; long lead Entry time and capex to launch Long-term leases with cellular Sticky subscriber base; "mission Stability of carriers critical" applications; high switching Cash Flow costs for users GHL Acquisition Corp. 11

Greenhill's Track Record of Public Company Stewardship Later Sold Public Company Greenhill (GHL) Greenhill & Co. S&P Mid Cap Investment Banking & Brokerage Hercules Offshore (HERO) Heartland Payment Systems (HPY) EXCO Resources (XCO) Energy Transfer (ETE) GHL Acquisition Corp. Note: Returns quoted from IPO price through closing price on 9/19/08. Highlighted companies have been acquired and returns are quoted from IPO price to acquisition price. 12

Transaction Overview Transaction Summary Acquirer GHL Acquisition Corp. ("GHQ") Iridium Holdings LLC Target Acquisition Structure Cash: $100 million ($22.9 million upfront from Greenhill investment; $77.1 million upon closing from GHQ cash balances) Up to $15 million additional cash pre-closing from Iridium balances to meet pending tax obligations of certain Consideration to sellers GHQ Shares: $360 million Iridium Holders $30 million payment to compensate for tax basis step-up, payable 90 days after closing $22.9 million investment by Greenhill referenced above will be not be contingent on closing of the GHQ acquisition, and will be made upfront in form of convertible debt 5 current Iridium outside directors plus CEO, 2 Greenhill, and 2 independent GHQ Board of Directors nominated directors Greenhill representative to serve as Chairman Approval by GHQ shareholders (approval requires that less than 30% of public shareholders vote against transaction and elect conversion) Approvals Requisite regulatory (e.g. HSR, FCC) approvals GHL Acquisition Corp. 13

Transaction Summary (cont'd) GHL Lockups Lockup on GHQ securities owned by GHL extended to 1 year (from 180 days), except sales via underwritten secondary offerings approved by Iridium Board after 6 months Iridium Shareholder No sales of GHQ shares for 1 year, except sales via underwritten secondary offerings approved by Iridium Board after 6 months Lockups 1.44 million GHQ founder shares held by GHL cancelled (bringing promote to 15% from Securities Forfeited approximately 17.5%) 8.37 million GHQ Founder Warrants held by GHL cancelled by GHL 2 million GHQ Private Placement Warrants held by GHL cancelled (6 million retained) Tender Offer Tender offer for GHQ shares/warrants of $120 million (less payments made to "no voters") to close concurrent with closing of the transaction Current Iridium director and executive grants vest upon transaction closing Management Equity New option grants made upon transaction closing to senior management totaling 2.0 million options with $10.50 strike price and 2.0 million options with $14.25 strike price Incentives GHL Acquisition Corp. 14

Transaction Valuation / Operating Comparison The Iridium transaction represents an attractive valuation relative to the Company's nearest competitor Iridium's valuation is made even more attractive by its higher growth, lower leverage and superior network coverage ($ in millions, except per share and subscriber data) Iridium Inmarsat Consideration Fully-Distributed to Existing Post-Combination Trading Iridium Owners Valuation Valuation Fully-Diluted Shares Issued/Outstanding 38.3 (1) 87.8 (2) 458.4 x Share Price $10.00 (3) $10.00 (3) $10.74(4) ------------------- -------------------- -------------------- Market Capitalization $382.9 $877.6 $4,921.6 Plus: Cash Acquisition Consideration 77.1 - - ------------------- -------------------- -------------------- Equity Valuation $460.0 $877.6 $4,921.6 Plus: Net Debt $130.8 (5) ($72.4) (6) $1,503.3 ------------------- ------------------- -------------------- -------------------- Enterprise Valuation $590.8 $805.2 $6,424.9 ------------------- -------------------- -------------------- Enterprise Value / First-Half 2008 Annualized EBITDA 5.5x (7) 7.5x (7) 14.8x June 2008 Total Subscribers / Active Terminals (Thousands) 280.5 (8) 280.5 (8) 235.4 % Growth from Year-Earlier 38.3% 38.3% 1.6% First-Half 2008 Annualized Revenue $312.0 $312.0 $623.2 % Growth from Year-Earlier 30.7% 30.7% 9.6% First-Half 2008 Annualized EBITDA $107.0 (7) $107.0 (7) $435.4 % Growth from Year-Earlier 55.4% 55.4% 8.4% Net Debt / First-Half 2008 Annualized EBITDA 1.2x (7) None (7) 3.5x Network Coverage Global Global No Polar Coverage Notes: (1) Represents shares issued to Iridium's pre-combination holders, including shares issued assuming conversion of Greenhill's $22.9MM convertible note. (2) Fully-diluted post-transaction, post tender-offer share count, including all non-forfeited shares and warrants. Assumes no GHQ shareholders vote against the transaction and elect conversion. Based on treasury method. (3) Assumes $10.00 GHQ share price, based on approximate cash in trust, net of GHQ transaction expenses at closing. (4) As of 9/19/08. Source: Bloomberg. (5) As of 6/30/08. (6) Estimated post-transaction, post tender-offer cash balance (including estimated cash flows through 12/31/08). (7) Based upon Operational EBITDA, as defined elsewhere in this presentation. (8) Iridium subscriber count has increased to over 305,000 as of September 2008. GHL Acquisition Corp. 15

Table of Contents 1. Transaction Overview 2. Overview of Iridium GHL Acquisition Corp. 16

Iridium is the world's largest and most sophisticated commercial satellite network providing global communications on the move - people, vehicles, aircraft, vessels, assets Global Network Providing Unique Capabilities 66 satellite polar orbiting constellation 8 in-orbit spares A single subscriber device works worldwide Ubiquitous coverage All oceans and land masses, including polar routes Any terrain Where terrestrial infrastructure is unavailable or undesirable Low earth orbit system provides numerous benefits and cost advantages for end users Satellite-to-satellite links create a secure mesh network in space GHL Acquisition Corp. 17

Overview of Iridium Leader in Mobile Satellite Communications Fastest growing full-service provider of mobile satellite services (MSS) Highly defensible position with little direct competition Strong and consistent financial performance Attractive MSS market growing at 15% annually through 2015(1) Significant current and future cash generation capability High-value industrial and Government customers R&D investments fuel new growth opportunities GHL Acquisition Corp. Note: (1) Source: Euroconsult. 18

Iridium is growing rapidly and consistently, as measured by subscribers, revenues and EBITDA Since June, Iridium's subscriber count has further increased to over 305,000 Strong Growth Trajectory Total Subscribers (in Thousands) 300 280 U.S. Government 32 250 Commercial 234 33% CAGR 200 32 174 150 143 29 94 115 28 248 100 27 202 59 22 146 115 50 13 72 88 46 0 2002 2003 2004 2005 2006 2007 1H2008 Revenue Operational EBITDA(1) ($ in $ in Millions) Millions) ( $300 $100 $260.9 $80 87% CAGR $76.3 $250 31% CAGR $212.4 $60 $53.8 +55% $53.5 $200 $187.7 $47.5 +31% $156.0 $40 $34.4 $150 $121.5 $119.4 $20 $100 $98.7 $3.3 $68.6 $0 $50 2002 20032004 2005 2006 20071H20071H2008 ($20) ($19.3) $0 ($40)($33.5) 2002 20032004 20052006 2007 1H20071H2008 GHL Acquisition Corp. Note: (1) Operational EBITDA excludes revenue and expenses associated with next generation constellation deployment that cannot be capitalized. 19

Overview of Iridium Experienced Management Team Matt Desch, CEO More than 28 years of senior executive experience including: CEO, Telcordia Technologies and, President, Global Wireless, Nortel Networks. Chairman of the Board of Airspan Networks and on the board of Starent Networks. Eric Morrison, CFO Has worked on the Iridium program for 16 years. Previously Controller and CFO, Iridium North America. John Brunette, Chief Legal & Administrative Officer More than 24 years of telecom experience. Previously EVP and later CEO of Teleglobe Inc. Greg Ewert, EVP - Global Distribution and Business Development More than 20 years of technology and telecom experience: Formerly SVP at Comsat International, SVP at Teleglobe, VP & General Manager Sprint International/GlobalOne, President of Sprint Intl. of Canada. Lee Demitry, EVP - Iridium NEXT More than 31 years of aerospace/satellite experience, 20 at the US Air Force leading many complex and advanced space and satellite programs. Previously VP of Engineering at GeoEye. John Campbell (Lt General USAF-retired), EVP - Government Programs 32 year career with US Air Force. Associate Director of Central Intelligence for Military Support for the CIA. Vice Director of the Defense Information Systems Agency (DISA) Don Thoma, EVP - Marketing and Product Management More than 24 years of aerospace and communications experience. Formerly VP Business Development and General Manager of ORBCOMM's Asset Tracking Business Unit John Roddy, EVP - Ground Operations and Product Development More than 28 years of telecom experience. Public Carrier Networks at Nortel Networks. Previously VP and GM Professional Services and VP of Technology President, Telcordia Global Services and SVP and CIO at Telcordia. GHL Acquisition Corp. 20

Overview of Iridium Strong Position in Growing Market Iridium has grown consistently since its re- launch, with subscribers and revenue growing at compound annual rates of 32% and 31% respectively, from 2002-2007 Attractive market for mobile satellite services (MSS) Total market $1.1B in 2007 Commercial terminals are projected to grow at 21% per annum Commercial service revenue projected to grow at 15% per annum Iridium is the fastest growing full service MSS player Number one provider of MSS to the US Government Total MSS Market Share 2001 Total MSS Market Share 2007 MSV Orbcomm Globalstar MSV Orbcomm Globalstar 3% 3% 1% 4% 0% Thuraya 9% 7% Iridium Thuraya 9% 13% Inmarsat 49% Inmarsat Total 2001 79% Total 2007 Iridium 23% Revenues: Revenues: $0.6 billion $1.1 billion GHL Acquisition Corp. Source: Euroconsult 2007 Revenue estimate, Raymond James Equity Research 2008 21

Overview of Iridium Iridium has superior coverage and network advantages relative to competitors and is growing market share Superior Competitive Position TREND COVER SVCS 2007 REVENUE 70% Voice $557M Global Broadband (GEO - 3 + 8 legacy) 100% Voice $261M Global Low Data (LEO - 66 High Data + spares) Regional Voice $146M (Mideast High Data and Asia) Broadband (GEO - 2) Regional Voice $98M (US & Low Data Continents) (LEO - 48) Global Low Data $28M (LEO - 24) GHL Acquisition Corp. Source: Euroconsult, Company Filings, and Raymond James Equity Research 2008 22

Overview of Iridium Global, Premium, and Profitable Iridium Position Relative to Competitors Regional vs. Global Regional Consumer Orientation Consumer Market Positioning Low-end Business Model Maturity Untried Operational Focus Spectrum Play Iridium Position vs. Competition Global Industrial High-end / Premium Mature / Developed Making Money GHL Acquisition Corp. Source: Iridium. 23

Overview of Iridium Strong Presence in Critical Applications Maritime Aviation 37% of commercial traffic 17,000+ aircraft in international waters equipped Crew calling Flight following Fisheries mgmt Cockpit communications Man-overboard Air safety services High Speed Data SSAS Government Land/Mobile (Handsets) ~32,000 DoD 197,000+ commercial subscribers voice subscribers Over-the Horizon Disaster Netted Emergency/rescue Blue Force Tracking operations In-Network calling Unattended Sensors Regional Pricing Quality Guarantee Machine-to-Machine (Asset Tracking & Telemetry) Low latency, and low cost critical global applications 150+ applications Fleet management Container tracking Oil and Gas telemetry Oceanographic data Subscribers up Subscribers up Subscribers up Subscribers up Subscribers up 26% 48% 6% 30% 157% Integral part of day-to-day operation of industry and governments GHL Acquisition Corp. Note: Subscriber growth reflects growth from 2Q07 to 2Q08 24

Overview of Iridium Iridium is an embedded part of DoD communications infrastructure since inception, with many new opportunities for growth Total Subscribers (6/30/08) U.S. Government 11% Commercial 89% Defense Department Anchor Tenant Customer Unique high security network that complies with military standards 100% global coverage, operated from single, secure gateway Significant investment by Department of Defense in secure gateway Large amount of Iridium user equipment in-place DoD anchor contract for service through its own secure gateway Contract in place since 2000 New five year(1) contract signed in Q1 2008 Serves all branches of DoD plus other international and government users Fixed fee per user, bulk access Average minutes-of-use in excess of 7 million / month Increasingly wide range of Department of Defense embedded applications Source of R&D funds for new products and services GHL Acquisition Corp. (1) As is customary for government contracts, Iridium's DoD contract is structured with a one-year term and four one-year options to extend. 25

Overview of Iridium Growth-Oriented Wholesale Distribution Model Value-Added Manufacturers 43 137 M2M devices Iridium Handset Value-Added Service Partners Value-Added Resellers Developers 1100+ Distributors Distributors Distributors End Customer OpenPort A Growing Network of Iridium Partners Providing Solutions to End-Customers Partners do Much of the Legwork in Developing New Products & Applications GHL Acquisition Corp. 26

Overview of Iridium Iridium expects to fund the capital requirements ($2.7 billion) primarily from internally generated cash flows and proceeds from secondary payloads Management sees no need for additional debt financing until 2014 given transaction with GHQ Expected peak financing need in 2016 of approximately $300 million Iridium NEXT - Our Second Generation Iridium has begun plans to replace current constellation Lockheed Martin and Thales Alenia competing for contract Launches to begin around 2013 New system has 15 year expected life Maintain unique attributes - 66 satellite LEO architecture, inter-satellite links, global coverage, security, availability Backward compatible for existing customers - maintains ongoing growth in existing cash flow base Improved data speeds, subscriber technology, core technology improvements (batteries, processors, solar cells) Valuable platform for global interconnected secondary payloads GHL Acquisition Corp. 27

Overview of Iridium Opportunity to Share NEXT Infrastructure Including secondary payloads on NEXT may significantly defray overall capital costs Significant interest from Government and industry in sharing NEXT global networked communications infrastructure for space observation Secondary payloads deployed on NEXT can revolutionize Earth sensing Unprecedented spatial and temporal coverage with 66 payloads Real-time data acquisition from on-board sensors Cost effective - < 20% the cost of dedicated satellites Potential new space services - global command, control and communications for independent satellites GHL Acquisition Corp. 28

Overview of Iridium Summary Financial Statements Iridium has successfully added subscribers rapidly and profitably over its operating history Since June, Iridium's subscriber count has further increased to over 305,000 ($ in millions, subscriber data in thousands) Years Ended December 31, Six Months Ended June 30, 2002 2003 2004 2005 2006 2007 2007 (2) 2008 (2) Subscribers: Commercial 46.2 71.6 88.2 115.3 145.7 202.5 172.6 248.5 U.S. Government 13.0 21.9 26.6 27.6 28.5 31.7 30.1 32.0 Total Subscribers 59.2 93.6 114.8 142.9 174.2 234.2 202.7 280.5 % Growth - 58% 23% 24% 22% 34% - 38% Revenues: Commercial $21.8 $42.5 $49.6 $60.7 $77.7 $101.2 $45.6 $61.8 U.S. Government 39.3 39.1 45.1 48.3 50.8 57.9 27.1 29.9 Equipment 7.5 17.0 26.8 78.7 83.9 101.9 46.6 64.3 Total Revenues $68.6 $98.7 $121.5 $187.7 $212.4 $260.9 $119.4 $156.0 % Growth - 44% 23% 54% 13% 23% - 31% Gross Profit $53.6 $73.3 $87.1 $115.6 $143.6 $185.9 $84.6 $113.9 % Growth - 37% 19% 33% 24% 29% - 35% % Margin 78.1% 74% 72% 62% 68% 71% 71% 73% Operational EBITDA (1) ($33.5) ($19.3) $3.3 $47.5 $53.8 $76.3 $34.4 $53.5 % Growth - - - - 13% 42% - 55% % Margin -48.8% -20% 3% 25% 25% 29% 29% 34% NEXT Costs - - - - - 1.8 0.7 3.3 GAAP EBITDA ($33.5) ($19.3) $3.3 $47.5 $53.8 $74.5 $33.7 $50.2 % Growth - - - - 13% 38% - 49% % Margin -48.8% -20% 3% 25% 25% 29% 28% 32% Notes: (1) Operational EBITDA excludes revenue and expenses associated with next generation constellation deployment that cannot be capitalized. (2) Unaudited. GHL Acquisition Corp. 29

Overview of Iridium Iridium's fixed cost business model allows a significant portion of any incremental new revenue to fall to the bottom line Iridium's Key Growth Strategies Continued Growth in Subscribers and Market Share Superior service offering and coverage advantage Network allows lower overall cost to end users Exploit weaker competitors Continued low churn as more devices "built in" to VAR offerings Continued Introduction of New Products 90+ VARs creating new applications and integrating Iridium into their products New handsets and lower-cost data modems Expanding into high-speed data New services ("push to talk" and iGPS) Expanding Sales Coverage New geographic coverage through licensing in large, high-growth markets (e.g. China, Mexico, Russia) Continually adding new VARs, service providers, manufacturers and developers Exploiting Regulatory Mandates to Grow Current Markets Air transport safety Fishing compliance Vessel identification and tracking for security Long-haul trucking driver safety GHL Acquisition Corp. 30

Overview of Iridium Merits of the Transaction The transaction will enhance value by allowing Iridium to emerge as a public company with no net debt, ready to fund continuing growth High quality business One of only two major players in the sector (Inmarsat the other) Only provider with truly global service US Department of Defense serves as long-term anchor customer Valuable, global spectrum holdings Satellite operations outsourced to Boeing Substantial scale $107 million Operational EBITDA(1) based on first half 2008 annualized Rapid growth 5 separate subscriber verticals, all growing First half Operational EBITDA(1) up 55% versus prior year Attractive valuation 7.5x trailing Operational EBITDA(1) based on annualized first half results (fully-distributed value, pro forma for transaction and GHQ warrants) Inmarsat trading at 14.8x annualized first half 2008 EBITDA Valuation enhancement potential New products and applications Brand enhancement from net debt-free balance sheet and public company status Note: (1) Operational EBITDA excludes revenue and expenses associated with next generation constellation deployment that cannot be capitalized. GHL Acquisition Corp. 31