Press Release

April 24, 2000

Motient and Research In Motion Announce Distribution Agreement for BlackBerry Wireless Email Solution

BlackBerry on Motient's Network To Support Microsoft Exchange Users

Reston, VA - Motient Corporation, formerly known as American Mobile Satellite Corporation (NASDAQ:SKYC), and Research In Motion Limited (NASDAQ: RIMM; TSE: RIM) today announced that Motient will offer the award-winning BlackBerry™ wireless email solution for use on Motient's industry-leading terrestrial wireless network. Motient will offer BlackBerry Exchange Edition™ to corporate customers across the United States.

BlackBerry is a secure, integrated, wireless email solution developed by RIM that allows mobile professionals to enjoy untethered access to their corporate email wherever they go. BlackBerry Exchange Edition is designed specifically for corporate environments using Microsoft® Exchange and addresses the strict IT standards required by Fortune 500 companies. BlackBerry has quickly become the leading wireless email solution among users of email networks running Microsoft Exchange.

The BlackBerry wireless email solution offered by Motient will deliver single mailbox integration with Microsoft Exchange to customers through a powerful combination of hardware, software and service. The end-to-end solution includes the RIM 850 Wireless Handheld™, integrated email/organizer software, PC docking cradle, PC synchronization software and enterprise server software with broad geographic coverage and in-building penetration provided by Motient's nationwide terrestrial network.

"We are pleased to announce the rollout of BlackBerry and to welcome Microsoft users onto the Motient network," said Motient Chief Executive Officer and President Walter V. Purnell, Jr. "The addition of BlackBerry to our service lineup speaks volumes about the ability of Motient's network to quickly respond to and support the needs of wireless email users. Because of the robust nature of this network, BlackBerry users will enjoy access to the high level of network reliability, speed, coverage, and deep in-building penetration that Motient already provides across a range of other wireless messaging and email applications."

"BlackBerry continues to gain popularity across North America as both a personal productivity tool and a corporate solution for enhancing workgroup communication and collaboration," said Jim Balsillie, Chairman and Co-CEO of Research In Motion. "Our expanded sales relationship with Motient provides RIM with an excellent opportunity to increase distribution for BlackBerry to reach and support an even broader base of customers."

About Motient

Motient (www.Motient.com) owns and operates an integrated terrestrial/satellite network and provides a wide range of two-way mobile and Internet communications services principally to business-to-business customers and enterprises. The company provides its industry-leading eLink^SM two-way wireless email service to customers accessing email through corporate servers, Internet Service Provider (ISP) and Mail Service Provider (MSP) accounts, and paging network suppliers. Motient serves a variety of markets including mobile professionals, telemetry, transportation, field service, and nationwide voice dispatch offering coverage to all 50 states, Puerto Rico, the U.S. Virgin Islands, and hundreds of miles of U.S. coastal waters.

About Research In Motion

Research In Motion Limited is a leading designer, manufacturer and marketer of innovative wireless solutions for the mobile communications market. Through development and integration of hardware, software and services, RIM provides solutions for seamless access to time-sensitive information including email, messaging, Internet and intranet-based applications. RIM technology also enables a broad array of third party developers and manufacturers in North America and around the world to enhance their products and services with wireless connectivity. RIM's portfolio of award-winning products includes the RIM Wireless Handheld™ product line, the BlackBerry™ wireless email solution, wireless personal computer card adapters, embedded radio-modems and software development tools. Founded in 1984 and based in Waterloo, Ontario, RIM is listed on the NASDAQ Stock Market (NASDAQ: RIMM) and the Toronto Stock Exchange (TSE: RIM). Investors may contact investor_relations@rim.net. Customers may contact info@rim.net. Web site: http://www.rim.net.

All trademarks, trade names, service marks and logos referenced herein belong to their respective companies.

Factors that could cause actual results to differ materially from those in the forward-looking statements in this news release are described in Motient (formerly American Mobile Satellite) Corporation's registration statement on Form S-3 (File No. 333-81459) and in Motient (formerly American Mobile's) annual report on Form 10-K for the year ended December 31, 1999 and its other periodic filings and reports with the Securities and Exchange Commission. Copies of such reports and filings are available upon request from Motient Corporation's Investor Relations Department.

Research In Motion, RIM, the RIM logo, RIM 850 Wireless Handheld, BlackBerry, BlackBerry Exchange Edition, the BlackBerry logo and the "envelope in motion" symbol are trademarks of Research In Motion Limited. Research In Motion and RIM are registered with the U.S. Patent and Trademark Office. All other brands, products and company names mentioned herein may be trademarks or registered trademarks of their respective holders. Forward-looking statements in this news release are made pursuant to the "safe harbor" provisions of the United States Private Securities Litigation Reform Act of 1995. Investors are cautioned that such forward-looking statements involve risks and uncertainties, including, without limitation, risks relating to possible product defects and product liability, risks related to international sales and potential foreign currency exchange fluctuations, risks related to the year 2000 issue, continued acceptance of RIM's products, increased levels of competition, technological changes, dependence on intellectual property rights and other risks detailed from time to time in RIM's periodic reports filed with the United States Securities and Exchange Commission and other regulatory authorities