This Echo is READ ONLY !   NO Un-Authorized Messages Please!
 ~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

4 July 2003

ISS On-Orbit Status 2 Jul 2003

Part 2 of 3

Yesterday, PCU (plasma contactor unit) #2 was activated at 3:00pm EDT
for plasma environment characterization.  It will remain in the
Xenon-discharge state for approximately 48 hours. This test is part
of a continuing effort to establish a relationship between the
charging hazard, ambient ionosphere conditions, and the flight
configuration while in LVLH attitude.  [The PCU-2 test was also run
in XPOP attitude, from 5/16-6/6.  PCU Xenon-emission current is the
sum of the electron currents collected from the ambient ionosphere
by (1) the high-voltage (160V) P6 solar arrays (when in ram position)
and (2) via low-voltage induction by the ISS structure moving through
the ionosphere.  The currently used FPP (floating potential probe)
instrument  data for determining the potential between ISS and the
ambient environment are very limited.  A more advanced Floating
Potential Measurement Unit (FPMU) will arrive on ULF-1.  The present
PCU-2 characterization enables forward-work on extending and
validating the plasma charging model used by the ground for when the
FPMU is in place.] 

MCC-H continues the 31hr. on-orbit thermal characterization test on
the station's S-band system, String 1, which it started yesterday.
[The test involves powering BSP (baseband signal processor) and XPDR
(standard TDRSS transponder) heaters off and on again after some
time, to obtain temperature readings during various orbit times,
including recordings during LOS (loss-of-signal).]

Power situation in the RS has degraded.  Ground specialists in
Houston and Moscow are carefully watching the issue, but at this time
it is not marginal as yet.  Appropriate power balancing and load
shedding plans are in place. [Of the eight 800A storage batteries in
the SM, one is completely unusable (#4), and three more units (#1,
#2, and #3) are showing reduced capacity (i.e., inability to fully
charge).  Currently, in LVLH attitude, peak loads on the USOS solar
arrays 2B and 4B are 17.5 kW (9.1 & 8.4, resp.), and the RS is
supplied with 1.9 kW from each, via SNTs (voltage & current
stabilizers/transformers) #22 and #23.  Should further deterioration
require an additional SNT (#21 from 4B), shell heaters in A/L, PMA-1
and Lab would be turned off, with no MSG activity permitted and HRF
(human  research facility) ops curtailed.  Should the SM require even
more power from an additional SNT (#24 of 2B) and the FGB from an
additional ARCU (American-to-Russian converter unit), all USOS shell
heaters would be turned off, no payload ops are permitted and 2B/4B
margins would be reduced to 300/600 watts.]

Today's CEO targets, no longer limited in the current LVLH attitude
and including the targets of the Lewis & Clark 200-year memorial
locations, were Istanbul, Turkey (looking a touch right.  The city
lies on both sides of the Bosporus strait), Tigris-Euphrates, Turkey
(many new dams have been constructed in the upper Euphrates in the
mountains of southern Turkey: most lay just left of track.  As soon
as water is impounded, populations begin irrigating new fields in the
immediate vicinity, and road and airfield installations spring up),
Baghdad, Iraq (looking left for a view of the entire cityscape),
Kuwait City, Kuwait (looking a touch left), Great Falls, MT (LEWIS &
CLARK SITE:  The Missouri River drops more than 400 feet in ten miles
here.  The explorers spent more than a month here in June-July 1805,
and noted the value of this site for hydro-power generation.  Now the
Ryan Dam occupies the site. The site lies on the river, at the city
of Great Falls, where the highway crosses the river, all at nadir),
Fort Mandan, ND (LEWIS & CLARK SITE: The expedition spent the winter
of 1804-5 here, and Sacagawea and her husband joined the group.  The
site is near the present town of Stanton.  Nadir pass: looking on the
south side of the large reservoir, Lake Sacagawea.  Stanton is on the
west bank of the Missouri near where the river turns sharply from
south to east), Chicago, IL (nadir pass), and Dallas, TX (nadir
pass). CEO images can be viewed at the websites 

http://eol.jsc.nasa.gov
http://earthobservatory.nasa.gov

See also the website "Space Station Challenge" at
http://voyager.cet.edu/iss/

U.S. and Russian Segment Status (as of 1:48pm EST).

Environmental Control and Life Support (ECLSS) and Thermal Control
(TCS):

Elektron O2 generator is powered On (16 amp mode).  Vozdukh CO2
scrubber is On (in Manual Mode 3/5).  U.S. CDRA CO2 scrubber is Off.
TCCS (trace contaminant control subsystem) is operating.  MCA (major
constituents analyzer) is operating.  BMP Harmful Impurities unit:
absorbent bed #1 in Purify mode, bed #2 in Purify mode (unit is
off).  RS air conditioner SKV-1 is On; SKV-2 is Off.


SM Working Compartment:  Pressure (mmHg) -- 742; temperature (deg C)
-- 26.4; ppO2 (mmHg) -- data invalid; ppCO2 (mmHg) -- data invalid.
SM Transfer Compartment:  Pressure (mmHg) -- 751; temperature (deg C)
-- 20.7.
FGB Cabin:  Pressure (mmHg) -- 752; temperature (deg C) -- 22.7.
Node:  Pressure (mmHg) -- 742.25; temperature (deg C) -- 22.2
(shell); ppO2 (mmHg) -- 171.2; ppCO2 (mmHg) -- 4.6.
U.S. Lab:  Pressure (mmHg) -- 745.12; temperature (deg C) -- 23.4;
ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a.
Joint Airlock (Equip. Lock):  Pressure (mmHg) -- 745.22; temperature
(deg C) -- 25.0; shell heater temp (deg C) -- 22.1, ppO2 (mmHg) --
n/a; ppCO2 (mmHg) -- n/a.
PMA-1:  Shell heater temp (deg C) -- 22.1
PMA-2:  Shell heater temp (deg C) -- 19.5.

(n/a = data not available)

Propulsion System (PS):

Total propellant load available: 3803 kg (8384 lb) as of 6/26
[SM(774) + FGB(2447) + Progress M(182) +Progress M-1(400)].
(Capability: SM -- 860 kg; FGB -- 6120 kg).

Electrical Power Systems (EPS):

Both P6 channels fully operational.  BGA (beta gimbal assembly) 2B
and 4B both in AutoTrack.
SM batteries:  Battery #4 is disconnected (failed 6/16); battery #7
is in "Cycle" mode; all other batteries (6) are in "Partial
Charge"
mode. Batteries #1, #2 and #3 showing degraded capacity.  FGB
batteries:  Battery #3 is offline; all other batteries (5) are in
"Partial Charge" mode. Plasma Contactor Unit PCU-1 in Standby mode;
PCU-2 in Discharge mode. 

 - Continued -

@Message posted automagically by IMTHINGS POST 1.30
---