USA 179

During the first six months of detailed observation, plotted below, twoline frequent orbital element sets were available from a non-public source. They enabled verification of the calculation method for the Mean Motion, as can be seen from how well the radio-derived values match with them.

The pattern that arises is that the satellite orbits for about 20 days and then an adjustment is made. Gravitational, rather than atmospheric, influences cause the Mean Motion to increases with time. In turn, this causes the ground track to drift in an easterly direction from day to day and, as the value gets higher, the ground track movement accelerates. The purpose of the adjustments is to reverse the drift and keep the location of the ground track within operational bounds. The initial routine was a major adjustment followed by a minor one but, towards the end of the year, it had evolved into two minor adjustments for every major one.

There are probably frequent smaller 'tweaks' between the ones plotted here but they are too fine (with certain exceptions) to be seen in the plot.

The Mean Motion seems to be bounded by values of 2.00675 and 2.00552, equating to orbital periods of 717.58 and 718.02 minutes respectively.

	USA 179	Lincoln, UK 2010 Mar 13, UTC Saturday
Maintained by: Robert Christy FBIS Contact: Zarya Home Page SDS Home Page USA 179 Background USA 179 Orbit USA 179 Switching USA 179 in 2006 USA 179 early in 2007 USA 179 late in 2007 USA 179 early in 2008 USA 179 ndot/2	Orbital Adjustments in the Second Half of 2006 During the first six months of detailed observation, plotted below, twoline frequent orbital element sets were available from a non-public source. They enabled verification of the calculation method for the Mean Motion, as can be seen from how well the radio-derived values match with them. The pattern that arises is that the satellite orbits for about 20 days and then an adjustment is made. Gravitational, rather than atmospheric, influences cause the Mean Motion to increases with time. In turn, this causes the ground track to drift in an easterly direction from day to day and, as the value gets higher, the ground track movement accelerates. The purpose of the adjustments is to reverse the drift and keep the location of the ground track within operational bounds. The initial routine was a major adjustment followed by a minor one but, towards the end of the year, it had evolved into two minor adjustments for every major one. There are probably frequent smaller 'tweaks' between the ones plotted here but they are too fine (with certain exceptions) to be seen in the plot. The Mean Motion seems to be bounded by values of 2.00675 and 2.00552, equating to orbital periods of 717.58 and 718.02 minutes respectively.	Radio Frequencies Frequency lists, transmission details Satellite Tracking Techniques, analysis and results of tracking activities Zarya Diaries Consolidation of individual mission diaries from the site (and more!) Orbital Events Ongoing Calendar of comings and goings in space The Kettering Group People, reminiscences and tracking equipment Sputnik Korolyov's efforts in getting the first satellite into orbit Luna The Soviet Union's programme of automatic exploration Vostok First pilot to orbit the Earth Voskhod Soviet programme to put multiple passengers into space Soyuz 4 and Soyuz 5 First docking in orbit of piloted spacecraft ASTP First docking of piloted spacecraft from different nations Salyut Chronology of missions to the first space stations Mir Detailed calendar of launches and activities in orbit ISS Mission calendar for the early years