MIRNEWS.494 – 10 Mar 2001
MIR-telemetry: MIR is still alive. Every evening the telemetry can be monitored via some frequencies during the 2nd and 3rd pass within our range in the Netherlands. If so this can be heard on 638.090 and 637.835 mc and now and then the transmitters in the 166 and 165 mc bands are transmitting simultaneously.
The good functioning of the communication systems, so the downlink telemetry from MIR and the Progress-M1-5 as well as the remote controlled command channels in the complex is a must. Failures of these systems will hamper (or even make impossible) the controlled descent into the earth’s atmosphere.
Ballistic details: TsUP still issues daily reports about the decay of MIR. Around 12.02 the daily descent rates were less than 1000 Meters but after 15.02 these values increased and were almost 2000 Meters during the last week. In the last 24 hours on 10.03 the complex’s descent was 2100 Meters. At this moment (10.03) the solar activity is very high: F 10.7 is 165. Variations in this activity hamper calculations of exact predictions.
Thus far all reports stated that as soon as MIR would descend pass the altitude of 250 KM TsUP would administer 3 braking impulses to achieve the altitude of 215 KM from where a 4th and last impulse had to bring the complex back into the atmosphere for decay over the Pacific east of New Zealand. (Position 47 degrees South, 140 degrees West)
Last week the operation plan has been changed. To economize fuel the Russians decided to postpone braking impulses and to continue the natural drag until 220 or 215 KM from where 2 short impulses will be given within a period of 6 hours. The next day a long impulse will bring the complex into the atmosphere and on the destruction trajectory.
The last ballistic report gives a prediction for the altitude 220 KM in the period from 18 until 23.03.
After entering the earth’s atmosphere MIR needs approx. 45 minutes to reach the target area after disintegrating between 90 and 60 KM. (If the optimism of the responsible authorities will be justified.)
Chris van den Berg, NL-9165/A-UK3202
