FE-1 Nikolai Budarin performed another substantial IFM (in-flight maintenance) in the FGB, changing out of one of its 800A batteries. A new storage unit replaced the failed battery #2,- a 1.5-hr task. The old 800A will be discarded on Progress. This restores all six FGB batteries to service. [Last change-out (Battery #1) was on 2/25.]

In the Service Module (SM), Budarin later removed a time synchronization unit (BSV-M) on one of the PPS system power panels and replaced it with a spare delivered by Progress 10P/M-247. [For the R&R, the BITS2-12 onboard measurement telemetry system and the Vozdukh CO2 absorber were switched off and turned back on afterwards.]

CDR Kenneth Bowersox began today's FOOT (foot/ground reaction forces during space flight) experiment by setting up the video equipment for recording the subsequent EMG (electromyography, i.e., muscular electric signals recording) calibration and day-long experiment run. The VTR recording was controlled from the ground. Bowersox's teleconference yesterday with the FOOT ground team was well received.

For FE-1 Nikolai Budarin, it was time for the second part of the current MBI-8 Profilaktika ("countermeasures") fitness test series, today with the NS-01 load trainer on the VELO (stationary bike) ergometer. [This fitness test consists of four types of exercise, viz., neck tilting (back/forward), simultaneous forearm flexing, trunk extension, and trunk flexes. Each type of exercise consists of a series of 15 motions repeated two times. Load levels are selected by the ground and do not change from test to test. Gas analysis, subjective evaluation of physical exertion levels, and blood test for lactate and Creatine Kinase levels are also performed as a part of this test, using the TEEM-100M gas analyzer, AccuSport analyzer, and Reflotron-IV blood analyzer.]

Evaluation of the two completed InSPACE experiment runs in the MSG (Microgravity Science Glovebox) is continuing. [After the first run on 3/31 with coil assembly 004 (CA004), lack of any discernable microstructures in the MR fluid indicated that the magnetic field strength may have been too low and/or particle size too small. Yesterday's second run used an increased magnetic field strength (current amplitude increased from 0.350 A to 1.2 A). For the continuation of the InSPACE operations next week, the tentative plan is to increase both field strength and sample particle size. This will be accomplished by utilizing CA003 (which has particles with a diameter of 0.62 microns) and setting a high current amplitude.]

Troubleshooting continues on the EVA battery recharging with BC-1 (battery charger 1). [As part of today's BSA (battery stowage assembly) battery recharge termination task, Don Pettit was to attempt to charge the helmet light batteries in BC-1 without the other battery chargers powered on. This would tell engineers if there is a noise interference issue associated with the other chargers. If BC-1 charging is unsuccessful, he was to remove the helmet light batteries from the charger and install them in BC-2,-3 and -4 to complete the charge.]

As part of EVA preparations, Don Pettit was also scheduled to perform a checkout of the SAFER (simplified aid for EVA rescue) units.

Afterwards, the crew conducted an in-depth review of the updated EVA timeline and later tagged up with the ground via S-band. Preparatory to the review and discussion, new timeline material and drawings of the ammonia fluid QD (quick disconnect) couplings for SPD (spool positioning devices) installation were uplinked. [Objectives of the 6.5-hr. EVA oin 4/8 include (1) S0/S1/P1 truss segment tasks like reconfiguring electrical connectors to provide additional inhibit to prevent SSAS (segment-to-segment attachment system) release, and NTA (nitrogen tank assembly) inspection to troubleshoot its heater problem; (2) R&R of the failed MT RPCM 3A (mobile transporter/remote power controller module #3A); (3) reconfiguring of CMG (control moment gyroscope) connections to ensure that no single EPS (electrical power system) failure will result in the loss of two of the three operating CMGs; (4) installation of two SPDs on Lab HX (heat exchanger) fluid QDs; (5) re-installing and securing of a QD thermal cover on the S1 RBVM (radiator beam valve module); (6) freeing the S1 CETA (crew equipment translation aid) railcart light stanchion and completing the light installation aborted during Stage EVA1; (7) and get-ahead tasks as time permits, such as tool retrievals and photo ops.]

Budarin completed his regular daily inspection of the BIO-5 Rasteniya-2/Lada-2 ("Plants-2") plant growth experiment.

Don Pettit conducted the daily routine maintenance of the SM's SOZh life support system (including ASU toilet facilities), while Sox prepared the daily IMS inventory delta file and performed the regular Lab payload status checkup (PCG-STES010).

Don also completed a "zero" calibration run with the CSA-CP (compound specific analyzer-combustion products), then activated and deactivated the CSA-CP for a cabin air composition data take. A planned sampling with the GSC (grab sampler container) was deferred.

The crew downlinked two messages of greeting, one to the Gagarin Cosmonaut Training Center (GCTC) in Korolev near Moscow on the occasion of Cosmonautics Day on April 12, the other to address the Fifth International Science/Technical Conference, on the theme "Space Science: Theory and Reality". [Cosmonautics Day observes the date of April 12, 1961, when Yuri Gagarin became the first human in space. John Glenn followed in February 1962 as first American and Valentina Tereshkova in June 1963 as first woman. "We wish a wonderful holiday to the command staff, all pilot cosmonauts, and all GCTC specialists on this, our professional holiday."]

The conjunction with a Delta 2 rocket body (object #21150), predicted for tonight after midnight, has moved to a calculated miss distance of 31.1 km. No DAM (debris avoidance maneuver) by Progress is required. The planned SM and FGB solar array efficiency test planned for tomorrow remains on schedule, as does the first of two Progress reboosts, scheduled for Friday (4/4).

During last night and ending this morning at 7am EST, MCC-H and its support group in Moscow (HSG) performed a BCC (backup control center) dry-run in test mode, with no involvement of ISS crew or vehicle. [BCC utilizes the HSG command server and telemetry server. In test mode, HSG (as BCC) sent a single not-for-uplink PPCP (preplanned command packet) to MCC-M/TsUP, then cancelled it after successful transmission. MCC-M played back the ACT (American contingency telemetry) recorded during the ACT checkout on 3/31/03, with HSG confirming successful receipt. TsUP commanding to the Russian segment (RS) via U.S. S-band as well as MCC-H-to-TsUP flow of status telemetry were also not affected, but MCC-H had no real-time telemetry and command capability via Russian ground stations (RGS).] Today's CEO (crew earth observations) targets, currently restricted by flight rule constraints limiting the use of the science window in the Lab, were Cape Town, South Africa (nadir pass over this major port and industrial city of South Africa. Margins of the city, of greatest interest in city-growth studies, extend 30 km east from the city center [at the foot of the Table Mountain massif]), Industrialized SE Africa (smog-smoke-dust loadings can accumulate for many days under the semi-permanent high pressure systems that dominate the subcontinent in summer and winter. Looking left and right for oblique images), Johannesburg, South Africa (looking right for the center of the 150-mile-long metropolis centered on the gold mining city of Johannesburg), Patagonian Glaciers (unusual situation of cloud banking up on the desert [east] side of the southern Andes, with clear skies on the west [Pacific] side. Crew was to shoot seldom seen west-side glacier tongues), Kuwait City, Kuwait (nadir pass), Western Mediterranean Aerosol (smog buildup likely. Looking left toward source regions of France and northern Italy), Eastern Mediterranean Aerosol (smog buildup likely. Looking left up the Adriatic Sea towards the mouth of the Po valley, a valley with the worst air pollution in Europe. Smog tongues may extend visibly into the eastern Mediterranean), Lower Amazon River Basin (good pass for documenting the position of islands in the complex mouth of the Amazon. Looking just left. This largest river on the planet moves islands at unexpectedly fast rates), and Northern South America fires (Dynamic event: Numerous fires reported along the northern edge of the Amazon rainforest in eastern Colombia and southern Venezuela. Looking left and right and shooting obliques to document extent of smoke pall). 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 12:45pm EST).

Environmental Control and Life Support (ECLSS) and Thermal Control (TCS):
Elektron O2 generator is powered Off. Vozdukh CO2 scrubber is On (manual mode 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. RS air conditioner SKV-1 is On; SKV-2 is Off.

SM Working Compartment: Pressure (mmHg) -- 745; temperature ( deg C) -- 27.6; ppO2 (mmHg) -- 183.1 (suspect); ppCO2 (mmHg) -- 2.4 (data suspect).
SM Transfer Compartment: Pressure (mmHg) -- 751; temperature ( deg C) -- 20.2.
FGB Cabin: Pressure (mmHg) -- 752; temperature ( deg C) -- 22.0.
Node: Pressure (mmHg) -- 739.44; temperature ( deg C) -- 23.1 (shell); ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a.
U.S. Lab: Pressure (mmHg) -- 741.48; temperature ( deg C) -- 22.2; ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a;
Joint Airlock (Equip. Lock): Pressure (mmHg) -- 741.58; temperature ( deg C) -- 20.9; shell heater temp ( deg C) -- 21.4, ppO2 (mmHg) -- 166.6; ppCO2 (mmHg) -- 4.2.
PMA-1: Shell heater temp ( deg C) -- 25.8
PMA-2: Shell heater temp ( deg C) -- 14.7

(n/a = data not available)

Propulsion System (PS):
Total propellant load available [SM(774) + FGB(2746) + Progress(474] --- 3994 kg (8805 lb) as of 3/27/03. (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 (sun-following).
SM batteries: All batteries (8) are in "Partial Charge" mode.
FGB batteries: Battery #2 is in "Cycle" mode; all other batteries (5) are in "Partial Charge" mode.
Plasma Contactor Unit PCU-1 and PCU-2 both in Standby mode.

Command & Data Handling Systems:
C&C-1 MDM is prime, C&C-2 is back-up, and C&C-3 is in standby.
GNC-2 MDM is prime; GNC-1 is Backup.
INT-1 is operating; INT-2 is Off.
EXT-1 is On (primary), EXT-2 is Off.
LA-1, LA-2 and LA-3 MDMs are all operating.
PL-2 MDM is On (primary); PL-1 MDM is Off
APS-1 (automated payload switch #1) and APS-2 are both On.
SM Terminal Computer (TVM): 3 redundant lanes (of 3) operational. Being upgraded.
SM Central Computer (TsVM): 3 redundant lanes (of 3) operational. Being upgraded.

Attitude Control Systems:
3 CMGs on-line (CMG-1 failed).
State vector source -- U.S. SIGI-1 (GPS)
Attitude source -- U.S. SIGI-1 (GPS)
Angular rate source -- RGA-2

Flight Attitude:
XPOP (x-axis perpendicular to orbit plane = "sun-fixed" [yaw: -179.0 deg, pitch: -8.8 deg., roll: 0 deg]), with CMG TA (thruster assist) Momentum Management.
Solar Beta Angle: 25.4 deg (magnitude decreasing).

Communications & Tracking Systems:
FGB MDM-1 is powered Off; FGB MDM-2 is operational.
All other Russian communications & tracking systems are nominal.
S-band is operating nominally.
Ku-band is operating nominally.
Audio subsystem operating nominally.
Video subsystem operating nominally (VTR1 is operable again).
HCOR (high-rate communications outage recorder) is operating nominally.

Robotics:
SSRMS/Canadarm2 based at Lab PDGF with Keep Alive (KA) power on both strings.
MBS: KA power on both strings.
MT: latched at WS4, with KA power.
POA: KA power on both strings.
RWS (robotics workstations): Lab RWS is Off; Cupola RWS is Off.

ISS Orbit (as of this morning, 3:21am EST [= epoch]):
Mean altitude -- 388.8 km
Apogee -- 394.4 km
Perigee -- 383.3 km
Period -- 92.33 min.
Inclination (to Equator) -- 51.63 deg
Eccentricity -- 0.0008265
Orbits per 24-hr. day -- 15.59
Solar Beta Angle: 25.4 deg (magnitude decreasing)
Mean altitude loss in last 24 hours -- 200 m
Revolutions since FGB/Zarya launch (Nov. '98) -- 24917
For more on ISS orbit and worldwide naked-eye visibility dates/times, see http://www.hq.nasa.gov/osf/station/viewing/issvis.html