It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Three-axis attitude control is maintained in the orbital configuration by automatic momentum exchange between three momentum wheels. Onboard magnetic coils provide controlled interaction with the Earth's magnetic field to prevent the accumulation of wheel secular momentum. Operations of these coils is under control of the closed loop spacecraft attitude control system. Both the momentum wheels and gyroscopes are backed up by a fourth skewed unit for redundancy.
DMSP-F13 flew in a 800-kilometer sun-synchronous polar orbit popular for weather and spy satellites.