At least three projects with the name Orion are known.
1. A US secret project that tests out recovered alien propulsion systems:
Material published on the Serpo site in August 2006 mentions a Project ORION. It allegedly is a fairly recent project that since 2002 tests alien propulsion systems at the Nevada Test Site.
Other sources mention different names for such programme. See Pluto, Redlight and Snowbird.
It is possible however, that Orion would be the more recent name.
A similar programme exists in Canada and is called Magnet.
2. A French project that monitors sattellites passing over French territory:
Project Orion also is the name of a programme in France, developed by the French Ministry of Defense, for the purpose of monitoring, identifying and predicting the passage of sattellites over French territory.
3. Greer's Project Orion that focused on 'new energy' research:
Steven Greer started a project that investigates 'new energy' sources. It started off with research into ZPE / Zero Point Energy, but later on also included research into Hydroxy Gas Energy Systems, Permanent Magnet or Pulsed Motor/Generators, and Electrogravitic/Magnetogravitic Propulsion and Energy Systems. (Source: www.siriusdisclosure.com/orion-project/).
Greer's Orion Project is no longer continued as a separate project, and has been integrated in his Sirius Disclosure Project.