RADARSAT Constellation Mission contract update

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), a provider of essential information solutions, announced today that the Canadian Space Agency has authorized the Company to start the design phase (Phase C) of the RADARSAT Constellation Mission. This authorization is limited to $11.8 million (CAD) and is expected to be completed by June 11, 2010.

The Company successfully completed work on Phase B in February 2010. This phase was originally announced in November 2008.

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.

The Company's common shares trade on the Toronto Stock Exchange under the symbol TSX:MDA.

Related Websites:
www.mdacorporation.com
www.asc-csa.gc.ca

Forward-Looking Statements
This release contains forward-looking statements and information, which reflect the current view of MacDonald, Dettwiler and Associates Ltd. (MDA) with respect to future events and financial performance. The forward-looking statements in this regard include statements regarding the award of a government 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. The factors and assumptions underlying the forward-looking statements in this release include contracts with any government agency 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 changes in government priorities, funding levels, contracts and regulations; satellite failure; and failure to anticipate changes in technical standards and products offerings or comply with requisite standards; failure of third parties and subcontractors; and failure of systems to meet performance requirements.

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