Subject: [SLR-Mail] No. 6: Resurs-O1-3 and Meteor2-21 Tracking
From: Daniel Nugent, Nasa <[Mailed  EDC <slrmail@dgfi.badw-muenchen.de>]>

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SLR Electronic Mail          1996-01-02 19:00:00 UTC           Message No. 6 
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Author: Daniel Nugent, Nasa
Subject: Resurs-O1-3 and Meteor2-21 Tracking


Dear Colleagues,

On 31 August 1993, a Russian made Meteor2-21 satellite was placed into a 930 
kilometer, 82.5 degree inclination orbit by a Russian launch vehicle.  This 
satellite is primarily a meteorological satellite with 3-axes stabilization. 
 On 4 November 1994, a Russian Resurs-O1-3 satellite was launched into a 640 
kilometer, sun-synchronous orbit at a 98 degree inclination.  Resurs-O1-3 
carries two multi-spectral scanners and is primarily for natural resource 
studies.  Both of these satellites also carry retroreflectors for Satellite 
Laser Ranging tracking.  For NASA SLR support purposes, the Meteor2-21 and 
Resurs-O1-3 satellites are being referred to as Fizeau and Resurs, 
respectively.

Fizeau and Resurs have been outfitted with specially designed 
retroreflectors to support an experiment to measure the fizeau effect. 
 Basically, these experiments will be used to measure the speed of light in 
a moving reference frame.  To do this, the experimental package contains two 
quartz and two hollow retro-reflector corner cubes.  These cubes are 
oriented so that only one cube should be visible at any time to a ground 
based observer.  Therefore, the pass up-side  versus down-side reflected 
receive signal strengths are expected to be appreciably different.

Ultimately, the purpose of this support is to determine satellite return 
signal strength.  Therefore, it is extremely important not to change the 
receive signal level once satellite data is being recorded.  The problem may 
arise where the return signal strength may be so great as to saturate one`s 
detector apparatus.  In such a case, a determination must be made to either 
1) continue tracking, if the saturation is not so severe as to damage one`s 
equipment, or 2) steer off the satellite altogether, so as not to corrupt 
the energy data measurements already recorded.  Again, the importance here 
is to maintain a constant  receive attenuation configuration.   For the 
purpose of the experiment, we are not overly interested in the accuracy of 
the range measurement, per se; although it is required to maintain an 
accurate orbit.

It has been pointed out that some systems have no means to measure laser 
return signal strength on a shot-by-shot basis.  In these cases, the 
analysis uses the return ratio, number of received pulses versus number of 
transmitted pulses, as an indication of relative signal strength.  The logic 
here being that the greater the return signal strength, the greater the 
number of returns being recorded.  Though these measurements are affected by 
viewing conditions, over a period of time visibility effects can be factored 
out.

The SATIDEN for Fizeau is 9305501 and for Resurs is 9407401.  The Fizeau 
satellite support designator is G5050MS and the Resurs designator is 
G1333MS.  Acquisition data is available from the CDDIS under filenames 
FIZ*.TIV and RE3*.TIV for Fizeau and Resurs, respectively.  Stations may 
download these files from the CDDIS, to verify correct processing of the 
TIV, at their convenience.  Acquisition data anomalies should be reported to 
this office as soon as possible.  Fizeau and Resurs support will be 
prioritized between Starlette and Ajisai (..., Starlette, Fizeau, Resurs, 
Ajisai, ...).

Stations capable of supporting the Fizeau and Resurs missions are requested 
to incorporate these satellites into their tracking schedules, as 
appropriate.  Please direct all questions, comments, and concerns regarding 
these experiments or their support requirements to Dr. Viktor Shargorodsky, 
Russian Academy of Science, via Natalia N. Parhomenko at 
natali@ricimi.msk.su.

Best regards,
Daniel Nugent
Supervisor, Network Operations
NASA Satellite Laser Ranging Program



[Mailed From: EDC <slrmail@dgfi.badw-muenchen.de>] 

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