All ISS systems continue to function nominally, except as noted previously or below. Day 158 for Expedition 4 on orbit and Day 557 of continuous station residency.

CDR Yuri Onufrienko performed troubleshooting on the failed Elektron oxygen generator by repeating the R&R of its Liquid Unit (BZh) done on 4/26. Moscow considers the failure of the main pump in the Liquid Unit to be due to air in the system, causing pump impeller cavitation. However, the source of this air is not clear at this time, and the troubleshooting is aimed at locating it. MCC-M and MCC-H are exploring all options, including the unlikely "worst case" scenario of an extended time period without a functioning Elektron. As of tonight, 15 SFOG (solid-fuel oxygen generator) candles have been used. [The current on-board supply of SFOGs, burning three per day for three ISS inhabitants, will last 50 days. There are apparently no new SFOGs ready to be launched any time soon. A new Liquid Unit would also not be ready in time for STS-111/UF-2. The Airlock HPGTs (high-pressure gas tanks) contain about 400 lbs. of gaseous oxygen. To conserve this supply, possible options under investigation include the use of O2 from the Shuttle, instead of from the Airlock, to support the EVAs during UF-2.]

Onufrienko replaced the FGB's ten smoke detectors (IDZ-2), which have reached the end of their certified lifetime. There are nine IDZs in the instrumentation cargo compartment (PGO) and one in the pressurized adapter (GA), docked to PMA-1 (pressurized mating adapter 1) and the Node. [These 184 x 130 x 102 mm units work by first ionizing air molecules inside their charge chamber with a small amount of radioactive material and then measuring the conductivity of the air. Air conductivity is reduced if it contains smoke particles, and the detectors trip at preset conductivity levels.]

CDR Onufrienko then assembled the Russian Molniya-SM (GFI-10) geophysical experiment hardware for a functionality checkout, preparatory to its operational run tomorrow (5/14) which will involve Russian ground stations (RGS). [Molniya-SM uses the twin-lens BFS-3M video-photometric system, mounted on SM window #1, for the study of atmospheric, ionospheric and magnetospheric electromagnetic interaction related to storms and seismic activities. There were a total of six sessions planned for Increment 4.]

FE-1 Carl Walz switched the CCAA (common cabin air assembly) air conditioner in the Lab from port to starboard and, per ground instruction, installed pressure caps on the fill and drain port QDs (quick disconnects) of the pump package assembly (PPA).

While FE-2 Dan Bursch started his turn at the final session of the renal (kidney) stone prevention research experiment, logging his food and fluid intake, Carl Walz is already into the second day, which required him to collect urine samples besides diet logging. After each collection, its ID is to be scanned and the sample then stowed.

On the BPS (biomass production system), Bursch today harvested the Brassica plant in PGC2 (plant growth chamber #2). The originally scheduled water sampling and then refilling the water tanks of the NDS (nutrient delivery system) and HCS (humidity control system) were cancelled. [Brassica rapa, also called Wisconsin Fast Plants, are a dwarf stock of the rapid-cycling plant, originally bred to have a 35-40-day life cycle so they could be used to teach biology in the classroom. Brassica were used in space for the first time by cosmonaut Leonid Kadenyuk as part of the CUE (Collaborative Ukrainian Experiment) on STS-87 in 1997.]

Walz removed the snubber alignment guides from ARIS Rack 2 which he had installed on 5/10 to mechanically lock down the rack for Onufrienko's subsequent autoclave removal from the shut-down ZCG (Zeolite crystal growth) furnace.

Walz and Bursch also worked on prepacking down-cargo for UF-2, with ground conference.

CDR Onufrienko downlinked a video greeting to be replayed for the participants of the 2nd Moscow Region Nursing Competition ("Nursing Stars") Finals to be held at Korolev/Moscow on 5/15. ["Dear participants, this entire galaxy is thanking you for overcoming the galactic virus with your knowledge, skill, and love. We congratulate you on your victory and wish you every success in your lives."]

The GPS-1 (global positioning satellite, set #1) failed yesterday due to a software anomaly in the GPS-1 receiver/processor, and subsequent troubleshooting did not yield the exact cause of the software anomaly. This particular GPS failure signature has not been seen on orbit before, however it has occurred infrequently in past ground testing. A power cycle (off/on) of the GPS hardware led to a successful recovery of GPS-1, which is now back to its normal business of calculating attitude and state vector solutions for the ISS guidance, navigation and control (GNC) system.

The Russian Diatomeya experiment (DZZ-2), designed to study the stability of geographic location and circumferential configuration (borders) of biologically productive areas of the world's oceans, had the following targets today: South Atlantic region of divergence of warm and cold currents, and shelf of the Republic of South Africa; Pacific Ocean bioproductive regions near California.

The U.S. CEO (crew earth observation) program today focused on Oman Post-Storm Runoff (Dynamic Event: The last vestiges of Tropical Storm 01A will probably have disappeared by the time of this encounter. As ISS approached the Oman coast, crew was to look left of track along the Oman coast and photograph [with electronic still camera, ESC] any remaining storm runoff and stream-borne sediment entering the Arabian Sea), E. Mediterranean Dust and Smog (the station approached the Libyan coast from the NW, allowing its crew to shoot ahead and left of track down the African coast. Dust masses continue to stream from Libya, outward over the SE Mediterranean. Slightly overexposed views will reveal the maximum extent of the dust, whereas normally exposed photos over the Sea will record dust thickness), Eastern United States (an approaching front should have driven the smoke from Okefenokee Swamp fires out over the Atlantic. Crew to use the ESC, looking ahead and to the right, to document seaward movement of smoke), Northern New Mexico Fires (Dynamic Event: The wildfires burning in the Sangre de Cristo range of New Mexico [east of Santa Fe] were directly left of track. Good ESC images of this event are candidates for posting to Earth Observatory. The crew's close approach permitted photographing individual fires/sources of smoke), Yucatan Smoke (Dynamic Event: An especially thick smoke mass is situated in the western Gulf of Mexico east of Tampico. Southerly winds are driving the smoke over the coastal plain of Mexico and Texas. Continued ESC documentation of both the far-traveled smoke and the sources in Yucatan and Central America were requested and will be of interest to Earth Observatory. Farther south, the Panama Canal was on track and it looked as though the area will remain reasonably free of clouds through the time of this overflight), Parana River (clear weather conditions should prevail over the upper drainages of the Parana and Uruguay Rivers. Documentation of land clearing, agricultural expansion along the drainages, and the condition of the interior wetlands was requested).
CEO images can be viewed at the website http://eol.jsc.nasa.gov

Environmental Control and Life Support (ECLSS) and Thermal Control (TCS):
Elektron O2 generator is Off (failed); SFOG candles (TGKs) are being used. Vozdukh CO2 scrubber is ON in MANUAL cycle mode #5 (vacuum pump failed). U.S. CDRA CO2 scrubber is Off. BMP Harmful Impurities unit: Absorbent bed #1 in Purify mode, bed #2 in Purify mode.

SM Working Compartment: Pressure (mmHg) -- 758, temperature (deg C) -- 26.4, ppO2 (mmHg) -- 159.1, ppCO2 (mmHg) -- 2.5 (probably invalid)

SM Transfer Compartment: Pressure (mmHg) -- 762, temperature (deg C) -- 19.9.

FGB Cabin: Pressure (mmHg) -- 756, temperature (deg C) -- 19.3.

Node: Pressure (mmHg) -- 752.16, temperature (deg C) -- 22.4 (shell); ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a.

U.S. Lab: Pressure (mmHg) -- 754.11, temperature (deg C) -- 24.3, ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a;

Joint Airlock (Equip. Lock): Pressure (mmHg) -- 754.01, temperature (deg C) -- 22.7; shell heater temp (deg C) -- 23.1, ppO2 (mmHg) -- n/a; ppCO2 (mmHg) -- n/a.

PMA-1: Shell heater temp (deg C) -- 22.9

PMA-2: Shell heater temp (deg C) -- 17.0

(Note: Partial pressures ppO2 and ppCO2 in U.S. segment [USOS] not available because MCA [major constituent analyzer] is failed and in Extended Life mode [= a state that preserves mass spectrometer vacuum but produces no pp data]). MSA (mass spectrometer assembly) and VGA (verification gas assembly) have been removed for return to Earth.

Electrical Power Systems (EPS):
Beta Gimbal Assembly (BGA) 2B in Autotrack mode, BGA 4B in Autotrack mode.
SM batteries: Battery #6 is offline (failed); battery #5 is in cycle mode; all other batteries (6) are in "partial charge" mode.
FGB: Battery #1 is in cycle mode; all other batteries (5) are in "partial charge" mode.
Plasma Contactor Unit PCU-1 in Standby mode; PCU-2 in Standby mode.

Thermal Control Systems:
Air conditioner SKV-1 is On. SKV-2 is Off.

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

Communications Systems:
All Russian communications & tracking systems are nominal.
S-band is operating nominally.
Ku-band is operating nominally.
Audio subsystem operating nominally.
Video subsystem operating nominally.
MCOR (medium-rate communications outage recorder) is operating nominally.

Robotics:
SSRMS/Canadarm2 at Progress viewing position, with Keep Alive power on both strings.
RWS (robotics workstations) are Off.
SSRMS Prime string Wrist Roll (WR) joint to be replaced on UF-2.

ISS Orbit (as of this morning, 7:41 am EDT):
Mean altitude -- 388.5 km
Apogee -- 394.2 km
Perigee -- 382.9 km
Period -- 92.3 min.
Inclination (to Equator) -- 51.64 deg
Eccentricity -- 0.0008367
Orbits per 24-hr. day -- 15.59
Altitude decrease -- 300 m (mean) in last 24 hours
Solar Beta Angle: -13.5 deg (magnitude decreasing)
Revolutions since FGB/Zarya launch (Nov. '98) -- 19861
Current Flight Attitude -- LVLH (local vertical/local horizontal = "earth-fixed": z-axis in local vertical, x-axis in velocity vector [yaw: -10 deg, pitch: -7.25 deg., roll: 0 deg]).

For more on ISS orbit and naked-eye visibility dates/times, see
http://www.hq.nasa.gov/osf/station/viewing/issvis.html

Source: NASA