**addition edited**
Further information has been received; Apple is collaborating with Space X to potentially offer an an alternative to Apple's offering with Globalstar. Globalstar is partnered with MDA on LEO satellites. This is more likely the reason for the decline.
Planet Labs, a peer competitor, has won a $230M satellite deal that is appears investors expected MDA to win. The drop though seems harsher than this news would imply. At this time, this is the only actual company news: Cubic Corporation announces that its Microelectronics business, Nuvotronics, has been selected by MDA Space Ltd. (TSX:MDA), a leading provider of advanced technology and services to the rapidly expanding global space industry, as part of the company’s supply chain for MDA AURORA™, a game-changing product line driving the transition from analog to digital satellite technology.