MDA to Divest Information Systems Business for $1.325 Billion

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), a provider of essential information solutions, announced today that the company has executed definitive agreements for the sale of its Information Systems and Geospatial Services operations to Alliant Techsystems (NYSE: ATK) for $1.325 billion in cash. Going forward MDA will focus exclusively on expanding its faster growing and more scalable Information Products business.

The transaction, which has been unanimously approved by each company's Board of Directors, is expected to close early in the second quarter, and is subject to MDA shareholder approval, regulatory approvals in Canada and the U.S., and various other consents and approvals typical for this type of transaction.

After closing of this transaction MDA will have about 1,100 employees, in Canada, the U.S., and Europe. MDA will fully retain its capability to build new products and operating infrastructures for its Information Products business, preserving the company's unique strength to deliver complex information systems to serve its customers.

MDA plans to use most of the proceeds from this transaction to invest in acquisitions that are aligned with its strategic plan for Information Products in the U.S., Europe, and Canada.

MDA President and CEO, Daniel Friedmann said: 'This transaction will enable us to focus our management and financial resources exclusively on our rapidly growing Information Products business, where many opportunities are waiting for us around the world. At the same time, the operations we divest will have greater growth potential under a complementary U.S. owner who recognizes its inherent value, and who is better positioned than we are to unlock this value in the U.S. market.'

The operations being divested will be led by MDA's Executive Vice-President of Information Systems, Magued Iskander. Upon closing ATK will create a separate business group, ATK Space Systems, which will include the operations being acquired from MDA, as well as other synergistic business assets of ATK in the U.S.

ATK's Chairman and CEO, Dan Murphy stated: 'We will benefit greatly from the addition of MDA's talented workforce, which like our own is known for its innovative, lower cost, yet highly reliable accomplishments. The operations we are acquiring are very complementary, and fully align with our strategic objective to provide complete end-to-end content to our domestic and international customers.

Banc of America Securities Canada Co. has acted as financial advisor to MDA in connection with the transaction. In addition BMO Capital Markets was retained to provide financial advice and a fairness opinion to the Board of Directors.'

IMPORTANT NOTICE: WEBCAST AND CONFERENCE CALL TODAY

MDA will host a webcast and teleconference today (Tuesday, January 8, 2008) at 5:00 p.m. EST/ 2:00 p.m. PST, to present background information and to answer questions from investors and analysts. The webcast and teleconference can be accessed at http://www.mdacorporation.com/investor/events.shtml. The teleconference is also accessible at 416-406-6419 or at 1-888-575-8232.

About MDA

MDA provides advanced information solutions that capture and process vast amounts of data, produce essential information, and improve the decision making and operational performance of business and government organizations worldwide.

Focused on markets and customers with strong repeat business potential, MDA delivers a broad spectrum of information solutions, ranging from complex operational systems, to tailored information services, to electronic information products.

MDA employs more than 3,000 people in locations across the United States, the United Kingdom, and Canada. The Company's common shares trade on the Toronto Stock Exchange under the symbol TSX:MDA.

About ATK

Headquartered in Edina, Minnesota, ATK is a world leader providing small satellites and large satellite sub-systems, hypersonic engines, rocket motors for spacecraft launch and orbit transfer - programs critical to reaching new space frontiers.

With approximately 17,000 employees and annual revenues in excess of $4.1 billion (USD), ATK is the world's largest producer of solid rocket motors and the prime contractor for the first stage of ARES I, NASA's next-generation launch vehicle. News and information can be found on the Internet at http://www.atk.com.

Related Websites:
www.mdacorporation.com
www.atk.com

Forward-Looking Statements

This release contains forward-looking statements and information, which reflect the current view of MacDonald, Dettwiler and Associates Ltd. with respect to future events and financial performance. Any such forward-looking statements are subject to risks and uncertainties and MDA's actual results of operations could differ materially from historical results or current expectations. Additional information on these and other potential factors that could affect MDA's financial results are detailed in documents filed from time to time with the applicable Canadian securities regulatory authorities.

The Toronto Stock Exchange has neither approved nor disapproved the form or content of this release.