| Date: | 1996-01-02 19:00:00 | |
| Sender: | Daniel Nugent, Nasa <[Mailed EDC <slrmail@dgfi.badw-muenchen.de>]> | |
| Subject: | [SLR-Mail] No. 6: Resurs-O1-3 and Meteor2-21 Tracking | |
| Author: | Daniel Nugent, Nasa | |
| Content: | ******************************************************************************** SLR Electronic Mail 1996-01-02 19:00:00 UTC Message No. 6 ******************************************************************************** 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 ******************************************************************************** |