Defence Research and Development Canada (DRDC) and the Canadian Space Agency (CSA) are jointly working to place a microsatellite, equipped with a small optical telescope, on orbit to detect and track both "deep-space" earth orbiting objects (orbital altitudes > 5000 km), and inner-earth orbit (IEO) asteroids. The satellite will be named the Near Earth Orbit Surveillance Satellite (NEOSSat), is baselined for launch in 4th Q 2008, and will be equipped with a 15cm diameter telescope capable of detecting 19.5th magnitude stars over a 100s integration. Other important design requirements of this telescope include the ability to observe to within 45 degrees of the sun (to better detect IEO asteroids) and the ability to observe to within 20 degrees of the anti-sun direction and remain power-positive. The mission is expected to cost $11M CDN (launch costs included, but operating and ground-station costs excluded). The scientific aims of the NEOSSat mission will be described and the results of the NEOSSat Phase-A will be presented. Test observations have been conducted using the MOST ("Microvariability and Oscillations of STars") microsatellite, the inspiration for NEOSSat, and the results of these observations will be shown here; these tests validate both the general concept of using a microsatellite for these types of observations, as well as the expected performance.