Riordan will be in charge of business development and customer engagement for Parsons' national security space business.
The AEHF-6 mission scheduled for March 19 will fly a 12U multi-manifest satellite carrying multiple U.S. government payloads.
Dutch launch broker Innovative Space Logistics and Firefly Aerospace signed a launch services agreement for launch opportunities on multiple Firefly Alpha missions starting this year.
Fresh off its purchase of geospatial intelligence firm OGSystems in January, Parsons is searching for more companies to buy that would further expand its presence in space, among other industries.
Parsons has been on a buying spree since 2011 as the company has sought to reinvent itself from an engineering and critical infrastructure contractor to one that can also play in intelligence, cybersecurity and cloud computing.