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ISS On-Orbit Status 29 May 2003

Part 2 of 3

As a result of the improved CO2 handling, ppCO2 (partial CO2 pressure
in the air) has come down to 3 mmHg in the SM this morning.  In the
Lab, the U.S. CDMK (CO2 monitoring kit) measured 3.2 mmHg in the
morning.  Thanks to a "zero" calibration performed on the MCA (major
constituent analyzer) yesterday, which corrected its readings down by
0.2 mmHg from earlier measurements, the difference between the MCA
and CDMK instruments now has shrunk to 0.3 mmHg.  [Hard Flight Rule
limit: 7.6 mmHg.] 

Tomorrow's conjunctions (close encounters) with the Megsat satellite
(object #25722) will require a debris avoidance maneuver (DAM).
[Further ahead-calculations of the three passes are showing all of
them within the "Red box" (collision probability greater than 0.0001,
one in ten thousand), with the closest miss distance, for the second
conjunction at 4:54-4:55pm EDT, today estimated to be 8 meters.  TCA
(time of closest approach) for the other two passes are 3:22pm and
6:27pm.  Maneuver commands have already been put in the system for
uplink to the SM computer as a PPL (pre-positioned load) file.  The
avoidance burn of ~1 m/s will be performed by Progress 10P thrusters,
using props from its refueling tanks.  This requires the burn to be
executed over Russian ground sites (RGS) to be real-time monitored,
and this sets the time for the DAM tomorrow, at 12:50pm EDT.  Megsat
is an Italian technology development satellite launched in 2000 as
one of several payloads on a Russian Dniepr rocket.]

According to Moscow, the DAM will have only minor impact on the
correct orbit phasing for the upcoming Progress 11P.  [Since Progress
11P flight to the ISS uses the seldom employed three-day template
(instead of two days), time available for determining any correction
parameters and updating the Progress autopilot is not that critical.]

For Soyuz 7S, in Fall 2003 for crew rotation, an orbit phasing burn
will be required.

The flight attitude assumed by the ISS for the 11P docking on 6/11
will require temporary power-downs on both the US and Russian
segments.  Details are currently being worked.

At 1:00pm EDT and 1:12pm, TsUP conducted the planned Kurs
approach/docking radar tests on the DC-1 "Pirs" side, first subset 1,
then subset 2.  Both were successful.  [With this, fueling of the
next Progress vehicle at Baikonur is moving ahead.  Launch of
11P/Progress M1-259 (M1-10) is set for 6/8 (Sunday) at 6:34am EDT.
The cargo ship will fly a three-day ascent profile, with docking
scheduled for 6/11 (Wednesday) at 7:11am EDT.  Linkup will be
radially at the DC-1 port (Progress 10P remains at the axial SM
aft-end port, and Soyuz TMA-2 is at the FGB nadir port).  Total mass
of 11P: 6934 kg (15287 lbs).]

Update on PCU (plasma contactor unit):   PCU-2 has been on Discharge
since 5/16, for characterization of its performance, viz., its Cesium
emission current, at exit from orbital eclipse (Earth's shadow) under
rapidly changing exit latitudes, as is the case from late May to
early June.  It will remain on Discharg until 6/6, then switched to
Standby.  [PCU 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.] 

Today's CEO targets, limited in the current XPOP attitude by flight
rule constraints on the use of the Lab nadir/science window, were
Industrialized SE Africa (conditions favorable for industrial haze.
Looking right towards the industrial heartland), Patagonian glaciers,
Chile (northern ice fields clear: looking right for detailed views of
glacier tongues), Rio de Janeiro, Brazil (nadir pass), Anatahan
Volcano, N Marianas (Guam under volcano ash alert for respiratory
health reasons.  By today, the winds will probably have reverted to a
more normal westward flow, thereby removing the danger. Looking left
of track about three degrees), Western Mediterranean Haze (conditions
favorable for haze buildup, especially draining down the Rhone and
Ebro valleys [in France and Spain respectively], both left of track),
and Lower Amazon River Basin (looking left and right for detailed
views of this great estuary). CEO images can be viewed at the
websites http://eol.jsc.nasa.gov and http://earthobservatory.nasa.gov

U.S. and Russian Segment Status (as of 1:06pm EST).

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

Elektron O2 generator is powered On (20 amp mode).  Vozdukh CO2
scrubber is On (manual mode 5, see note above).  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.  RS air conditioner SKV-1 is On; SKV-2 is Off.
SM Working Compartment:  Pressure (mmHg) -- 742; temperature (deg C)
-- 26.2; ppO2 (mmHg) -- data invalid; ppCO2 (mmHg) -- data invalid.
SM Transfer Compartment:  Pressure (mmHg) -- 751; temperature (deg C)
-- 21.1.
FGB Cabin:  Pressure (mmHg) -- 748; temperature (deg C) -- 23.0.
Node:  Pressure (mmHg) -- 742.62; temperature (deg C) -- 24.7
(shell); ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a.
U.S. Lab:  Pressure (mmHg) -- 744.61; temperature (deg C) -- 23.0;
ppO2 (mmHg) -- 170.7; ppCO2 (mmHg) -- 3.4.
Joint Airlock (Equip. Lock):  Pressure (mmHg) -- 744.72; temperature
(deg C) -- 31.0; shell heater temp (deg C) -- 26.0, ppO2 (mmHg) --
n/a; ppCO2 (mmHg) -- n/a.
PMA-1:  Shell heater temp (deg C) -- 24.0.
PMA-2:  Shell heater temp (deg C) -- 11.7.

(n/a = data not available)

Propulsion System (PS): Total propellant load available: 3573 kg
(7877 lb) as of 5/29 [SM(774) + FGB(2547) + Progress(252)].
(Capability: SM -- 860 kg; FGB -- 6120 kg).

Electrical Power Systems (EPS):

Both P6 channels fully operational.  BGA (beta gimbal assembly) 2B
and 4B both "directed" (non-solar tracking) mode ("sun slicer"
position, for drag reduction).
SM batteries:  Batteries #4 is disconnected (failed); battery #8 has
been replaced, in "Cycle" mode; all other batteries (6) are in "
Partial Charge" mode (battery #2 is exhibiting degraded performance).
FGB batteries:  Battery #4 is disconnected; battery #5 is in "Cycle"
mode; all other batteries (4) are in "Partial Charge" mode.
Plasma Contactor Unit PCU-1 in Standby mode; PCU-2 in Discharge mode.

 - Continued -

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