Subject: mirnews.379
From: "C.M. van den Berg" <[email-masked]>
To: "Igor Lissov" <[email-masked]>, "Friends Partners Space" <[email-masked]>, "Jonathan McDowell" <[email-masked]>, "Dave Larsen" <[email-masked]>, "dirk rensink" <[email-masked]>, "Dan Gauthier" <[email-masked]>
Date: Wed, 20 Aug 1997 09:48:51 +0200

MIRNEWS.379                            19 AUGUST 1997

In the morning of Monday 18.08 MIR transmitted to Earth videofilms and
images made during the redocking of S-TM26 on 15.08.  These transmissions
took place during a MIR-Altair-2 window between 0542-0628UTC. At 0601UTC
the crew stopped transmitting images and switched over to the coordination
of IVA preparations with TsUP.  During these activities the IVA was still
scheduled for 20.08. 

This day Progress-M35 returned to the complex and docked at the aft docking
port at 12.52.47UTC.  10 Seconds later both objects disappeared behind the
eastern horizon. 
Radiotraffic during the  beginning of the final phase of the docking
operation went  via Altair-2. Pr-M35 was at a distance of 800 M from MIR
and the approach speed was 11.31 cm/sec.  The crew of MIR observed the
approaching supply-ship on a display of the LIV camera. 

A few minutes before the objects came in my range Altair-2 had been
switched off and at 1246UTC traffic went on via 143.625mc.  S. reported
distances and approach speeds. At 125045UTC the distance was 12 M.  At a
distance of appr. 4 M. at  125156UTC Kurs did not work.  (Later on it
turned out that Kurs had switched itself off at a distance of 20 M due to
an irregularity in the attitude of MIR).  

After the docking of Pr-M35 I did not get time to relax for Geoff Perry
told me that TsUP just  had informed the press about a failure of the main
OBC of MIR, the Ts.V.M.-1.  Very often such failures happened before and it
always causes  a breakdown of the SUD (attitude control).  The SUD is
responsible for the good functioning of the gyrodynes and consequently
these gyroscopes cry off.  Commander Solovyov experienced a Ts.V.M.-1
failure in 1995 when he and Budarin made an autonomous flight with S-TM21
during the departure of Atlantis from MIR. S. immediately docked his ship,
went aboard MIR and restored the Ts.V.M.-1.   

During all available passes in the evening MIR and TsUP discussed the
problems. A specialist on Earth uttered the possibility that there was
something wrong with the Ts.M.O. (central exchange module), an interface of
the Ts.V.M.-1.  He told the crew how to find that module and he gave them
instructions for the repair.   Foale told one of his countrymen in Moscow
about his experiences during the final approach of Pr-M35. Through the
viewer of his videocamera he saw the Pr-M35 coming in very fast and he
realized that something was wrong.  He said: oh, no not again..  At that
moment Pr-M35 slowed down and stopped and Solovyov took over manually.
Foale emphasized that Pr-M35's  computer had switched off Kurs due to 
divergences in the attitude of MIR.  

This was for Solovyov the signal to switch over to manual control.  S.
performed a perfect docking: in fact the Kurssystem as well as the TORU
remote control worked well. 

Situation in the evening of 19.08.97:
The crew used the S-TM26 for the stabilization of MIR's attitude  and in
the course of 19.08  the solarpanels delivered twice as much energy as they
did on 18.08. Meanwhile the Ts.V.M.-1 has been repaired and was ready for
tests. At this point it was not known  whether attitude control of the
complex was provided by gyrodynes. .  
The crew resumed  preparations for the IVA now planned for Friday 22.08.97
or Saturday 23.08.97.  ECG's of the 'spacewalkers' have been transmitted to
Earth and Solovyov as well as Vinogradov  had already put on their
spacesuits and  checked the communication facilities and the electrical
contacts of these suits. 

Chris Vandenberg, NL-9165/A-UK3202