MDA to provide advanced technology solution for telecommunications satellite

For immediate release: August 21, 2009

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), a provider of essential information solutions, announced today it has signed a contract in excess of $10 million (CAD) with EADS Astrium, the Prime Contractor for Inmarsat’s Alphasat I-XL mission, to provide two advanced technology solutions for use on Alphasat, a telecommunications satellite. The solutions will be delivered in late 2010.

Alphasat is the first flight opportunity of the new European Large Platform Alphabus developed by EADS Astrium and Thales Alenia Space under ESA / CNES contract.

With a targeted launch date of 2012, Alphasat will support Inmarsat’s existing global mobile satellite services with coverage centered over Africa, in addition to providing additional coverage to Europe, the Middle-East and parts of Asia. Once launched, the satellite will provide increased capacity able to handle more than 750 channels with improved quality, particularly for satellite phone users.

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 3,200 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.

Related Websites:
www.mdacorporation.com
www.astrium.eads.net

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. The forward-looking statements in this regard include statements regarding the award of a contract. Any such forward-looking statements are based on MDA’s current expectations, estimates, projections and assumptions in light of its experience and its perception of historical trends. 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. The factors and assumptions underlying the forward-looking statements in this release include contracts not being terminated. Any such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from current expectations. MDA cautions readers that should certain risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary significantly from those expected. The risks that could cause actual results to differ from current expectations include failure of third parties and subcontractors; failure of systems to meet performance requirements and failure to anticipate changes in technology, technical standards and product offerings or comply with the requisite standards.

For additional information with respect to certain of these risks or factors, plus additional risks or factors, reference should be made to MDA’s continuous disclosure materials filed from time to time with Canadian securities regulatory authorities, which are available online at www.sedar.com or on MDA’s website at www.mdacorporation.com.

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

For more information, please contact:

Wendy Keyzer
MDA External Relations
Telephone: 604-231-2743
E-mail: wendy@mdacorporation.com