TIL The Lockheed SR-71 Blackbird used an Astro-inertial Navigation System to track Stars and determine its position and altitude. At Mach 3, the navigation system was accurate enough to limit drift to 1,000 feet (300 meters) off course.
en.wikipedia.orgSubmitted by shamelessterminator t3_118drfj in todayilearned
torsun_bryan t1_j9gplpj wrote
If you’re interested in reading a fantastic history of the SR-71, Area 51 and the Skunk Works, check out the book “Skunk Works” by the late Ben Rich, who took over for Kelly Johnson as head of Lockheed’s advanced development division.
In the book, he said the system was so sensitive it would lock onto bolts on the hangar roof, thinking they were stars.