MIRNEWS.478    28 APRIL 2000

ProgressM1-2:

This freighter with on board supplies of air, water and fuel for the MIR-
station departed from Baykonur to MIR on 25.04.00 at 20.08.02UTC. The
freighter had to dock at MIR on 27.04.00 at about 2130UTC , so 10 minutes
after MIR and PrM1-2 for us in Western Europe had disappeared behind the
eastern horizon.

ProgressM1-1:

This old freighter separated from MIR on 26.04.00 at 1633UTC for decay
over the Pacific east of New Zealand at 1927UTC.

Docking ProgressM1-2:

Approach and docking were executed with the help of the system Kurs. All
went flawlessly and smoothly. The freighter docked at the aft docking
port (Kvant-2 +X axis) on 27.04.00 at 21.28.48UTC. During the pass for
Western Europe just before the docking (orbit 81124, 2116-2121UTC)
radiotraffic revealed that all was going well. Just before LOS for my
position the distance to the docking part was 60 Meters and PrM1-2 was
proceeding exactly on course.

During the next pass for my position in orb. 81125, 225202258UTC, the
crew reported that they just had opened the hatches to PrM1-2. The
equalization of the pressures between the station and the freighter
lasted long this time. Kaleri said that the cargo bay of the PrM1-2 was
only half full. The air-seal was in good order, but there had been some
variations in the airpressure, which in his opinion were caused by the
differences in temperature. In 30 minutes the pressure decreased by 4 MM
mercury, and then the decrease stopped. At last the pressure inside the
station was 687 MM. The crew still had to install the clamps between the
PrM1-2 and the Kvant-1 docking port. These clamps make it impossible for
the freighter to wander away.

Meanwhile the control computer Svet had been switched on and Kaleri
loaded a number of commands into Svet for the automatic control of a
number of systems.

Then the cosmonauts crept into their sleeping-bags. (The bunks for
eventual tourists did not yet arrive.). For your scribe a good reason to
lay down in the arms of Morpheus.

Orbitcorrections:

The strong solar maximum causes an increased decay of the orbit altitude
of the MIR-spacestation. Some time ago this decay was about 100 or 150
Meters a day, now this is 4 or 5 times more. The only solution is to lift
the orbit of the complex by the use of the engines of the PrM-1 (mostly
this is the DPO, the engine for docking and orientation of the freighter
is used for that purpose), but once the engines of the Soyuz-TM30 were
used (on17.04). Later some more corrections had been given by the DPO of
PrM1-1. So it was difficult to calculate accurate orbit predictions.

Just before the separation of the PrM1-1 from the complex on 26.04 the
DPO of that ship gave another impulse to lift the complex.

More orbitcorrections can be expected during the next days, now with the
help of the DPO of PrM1-2.

The acceleration of the decay of the station causes anxiety at TsUP. More
even than the possibly still existing small air leakages in the station.
This also means that more money has to be reserved in the budget of the
users for extra fuel.

From the beginning of the 28th Main Expedition the crew has been very
busy with air-seal checks in several compartments and modules. This
search was intensified on 18 and 19.04.00. The crew worked with special
equipment, which had been brought to the station together with the
present crew. They spoke about an instrument called Bar and a thermo-
hygrometer. The cosmonauts had to disconnect cables in the PKhO (the
transition section) to make it possible to close the hatches through
which these cables are deployed. The coordination with TsUP during these
activities was very good and all went well during this risky work.

On 18.04 the crew alsmost knew where the small leak was and when they
were sure about the location they closed or plugged the leak with a cap
of stopper. During traffic in the pass on 19.04 in orbit 80988, 0701-
0721UTC TsUP and the crew discussed what kind of plug they should use. In
the next pass (orb. 80989, 0834-0841UTC) Kaleri reported that the
hissing sound ceased.

Thusfar it is not fully clear whether this leakage was the only one. Some
of the experts at TsUP were not sure for 100%. The air-pressure checks
are still going on, but less intensive than before the detection of the
leak. The leak was in a valve in the hatch between the PkhO and the
vacuumed module Spektr.

To be honest the crew of this expedition and the experts at TsUP did a
great job during the last weeks. In the first place there was the
reactivation of the important life support systems, but also the fact
that they managed to keep these systems operational and succeeded in the
detection of that small leak and the liquidation of that problem.

And let us not forget the flawless automatic approach and docking of the
PrM1-2 which had been equipped by a better system Kurs.

But another fact is less positive: nobody is queuing up in front of the
desks where tourists can book a trip to the MIR-spacestation. And thusfar
there has not been a single satellite begging MIR for repair or
maintenance. In fact a very good thing for the brave crew of MIR will
need all their time to keep their iron lung operational.

Chris van den Berg, NL-9165/A-UK3202.