2A Direct Current to Direct Current Converter Unit (DDCU) Trips: Today, all of the DDCUs on the 2A power bus tripped off simultaneously due to a bus undervoltage. This included DDCU 2A, DDCU LA2A, DDCU N2P2A, and DDCU N32A. The trip of DDCU 2A removed power from the 2A Pump Flow Control Subassembly (PFCS). Loads from the other DDCUs were picked up by parallel DDCUs and did not unpower hardware. Ground controllers stopped the 2A battery capacity test that was in progress and reactivated DDCU 2A and the 2A PFCS. Cooling has been re-established to the 2A Batteries. There were no thermal clock exceedances. Ground teams are reconfiguring the EPS system back to nominal and investigating the cause, suspecting that an unexpected power load during the battery capacity test triggered the bus undervoltage.

Mobile Servicing System (MSS) Operations: Overnight, Robotics Ground Controllers stowed the Materials International Space Station Experiment (MISSE) payload inside the SpX-10 Dragon trunk. The Robotics Ground Controllers then configured the Space Station Remote Manipulator System (SSRMS) and the Special Purpose Dexterous Manipulator (SPDM) for the start of the Robotic Refueling Mission (RRM) payload stow in the Dragon trunk later tonight. MSS performance was nominal.

Rodent Research-4: Today, the crew performed the last day of operations for Rodent Research-4. In coordination with ground specialists, the crew collected samples and stowed them in Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI) for return on SpX-10. The Tissue Regeneration-Bone Defect (RR-4) investigation studies what prevents vertebrates such as rodents and humans from regrowing lost bone and tissue, and how the microgravity extraterrestrial condition impacts the process. Results could lead to tissue regeneration efforts in space and a better understanding of limitations of limb regrowth at wound sites.

Water Sampling: Today the crew performed nominal Environmental Health System (EHS) Potable Water Dispenser (PWD) sampling for in-flight and post-flight analysis. In-flight Total Organic Carbon Analyzer (TOCA) samples were also performed. In coordination with the water sampling, the crew initiated the ESA sponsored Aquapad (Paper Analytical Device) technological demonstration and sampling using the Microbial Monitoring System (MMS) portion of the WMS experiment. By using the same water collected for the EHS sample, ground teams can evaluate the capabilities of the new hardware. For the MMS analysis, the crew configured the hardware to sample a low and high DNA concentration sample using the Razor Polymerase Chain Reaction (PCR) Microbial Monitoring System. The WMS is a set of hardware that monitors microbes, silica and organic material in the water supply on the ISS. The hardware ensures crew members can test and monitor the safety of their water supplies on future space missions, especially on long-duration missions to Mars, asteroids or other destinations where Earth-based testing would be difficult or impossible. Aquapad is a new approach developed by France’s CNES space agency: paper impregnated with powdered growth medium creates a 3D petri dish. When water is added, the microbes form colored spots revealing their locations. Using a tablet computer application the crew will photograph the dots to calculate precisely how many bacteria are present.

Advanced Plant Experiments (APEX)-04: The crew checked the status of the APEX-04 Petri Plate for condensation, then photographed the plate on the Advanced Biology Research Facility (ABRS) photogrid. The LMM Biophysics plate that was in the Light Microscopy Module (LMM) facility was inserted into the Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI) and APEX-04 petri plate was installed. The APEX-04 (Epigenetic change in Arabidopsis thaliana in response to spaceflight – differential cytosine DNA methylation of plants on the ISS) experiment investigates how spaceflight can affect an organism on a molecular level without altering its outward appearance. Previous research has demonstrated that large numbers of plant genes are expressed differently in space compared to plants on Earth, which can alter how plants grow. This investigation studies the entire genome of thale cress plants grown in space, creating maps of spaceflight-specific changes in certain groups of genes. Results give new insight into plants’ molecular responses to spaceflight, which benefits efforts to grow plants in space for food and oxygen.

Local Bus (LB) Mech Bus Checkout – Yesterday, in preparation for the Enhanced Processor Integrated Communications (EPIC) EXT Multiplexer/DeMultiplexer (MDM) upgrade, ground controllers performed a checkout of the LB-MECH-P1, P2, S1, and S2 buses. This checkout serves as a baseline assessment of the health of the buses before the new EPIC EXT MDMs are installed. There were no issues with the buses. When the Payload Attach System (PAS) 3 Umbilical Mechanism Assembly (UMA) was powered in the checkout, the mated switch did not show mated. This is thought to be caused by an already-known issue in which the UMA springs backdrove the active connector enough to lose the mated indication from the switch but did not demate the connector. External Stowage Platform (ESP)-3, which is on PAS 3, is receiving power nominally.

Today’s Planned Activities

All activities were completed unless otherwise noted.

Environmental Health System (EHS) Potable Water Dispenser (PWD) Sample Collect

Photo T/V (P/TV) Advanced Resistive Exercise Device (ARED) Exercise Video Setup

ASEPTIC. Glovebox-C Hardware Power On

ALGOMETRIA. Measurement Prep & Ops in the strain-gauge and thermal algometry modes

Fluids Integrated Rack Rack Doors Open

ASEPTIC. Taking samples from Glovebox-C surface after sterilization. Air Sample Collection Prep. H/W set up. Pump Activation.

APEX-04 Petri Plate Check

Verification of ИП-1 Flow Sensor Position

Total Organic Carbon Analyzer (TOCA) Potable Water Dispenser (PWD) Sample Analysis

Medical Kits Inventory Check

Light Microscopy Module APEX-04 change out of Petri Plates

Microbial Monitoring System Hardware Gather

DAN. Experiment Ops.

Microbial Monitoring System MWA Preparation

Urine Processor Assembly (UPA) EDV Transfer Hose Remove and Replace (R&R)

Fluids Integrated Rack Rack Doors Close

Photo/TV Camcorder Setup Verification

Rodent Research Node 2 Camcorder Video Setup

Rodent Research 4 Pink Habitat Transfer

Coliform Water Processing

Kurs-P Cable Reconnection from DC1 AFD to MRM2 AFD and photography of the connection location

Aquapad Double Water Sampling

Rodent Research 4 Green Habitat Transfer

ASEPTIC. Monitoring Automatic Pump Power off

OTKLIK. Hardware Monitoring

ASEPTIC. Preparation and Initiation of Air Sample Collection – “Vozdukh” #3. Pump Activation.

Total Organic Carbon Analyzer (TOCA) Sample Data Record

Microbial Monitoring System Sample Setup

Photo/TV Camcorder Setup Verification

ALGOMETRIA. Measurement Ops in the strain-gauge algometry mode

Microbial Monitoring System Sample

Wastewater Storage Tank Assembly (WSTA) Fill

Recharging Soyuz 732 IRIDIUM Satellite Phone – Setup (ФГБ1ПГО_2_224_1 0.5 CTB 1017 Soft Container 00044322R), initiate charge

Auxin Transport Sample Fixation Demonstration

Recharging Soyuz 732 IRIDIUM Satellite Phone – Battery Charge Monitoring

Recharging Soyuz 732 IRIDIUM Satellite Phone – Term

ЕДВ (КОВ) separation for ELEKTRON or ЕДВ-СВ Fill ЕДВ (КОВ) #1201 (ФГБ1ПГО_1_108) and ЕДВ-СВ #1242 (ФГБ1ПГО_1_109) from БВ1 Rodnik of Progress 435

Auxin Transport Fixation Kit GLACIER Retrieval

ASEPTIC. Monitoring Automatic Pump Power off

Water Resource Management (WRM) Potable Bus Sample

ASEPTIC. “Vozdukh” #2, 3 and “Poverkhnost” #2-5 Withdrawal from the box and placing into в Cryogem-03.

Rodent Research 4 Tan Habitat Transfer

СОЖ maintenance

Microbial Monitoring System Data Transfer

ASEPTIC. Glovebox-C Power Down

VELIKOE NACHALO. Video Report about Glovebox-C

CONTENT. Experiment Ops

IMS Delta File Prep

ASEPTIC. Closeout Ops with Glovebox Hardware Tagup with specialists

Rodent Research 4 MELFI Insert

Photo T/V (P/TV) Advanced Resistive Exercise Device (ARED) Exercise Video Stow

ALGOMETRIA. Measurement Ops in the strain-gauge and thermal algometry modes Closeout Ops

Completed Task List Items

On-Orbit Hearing Assessment (O-OHA) with EarQ Software Setup and Test

Habitability Human Factors Questionnaires

Dragon Cargo Message #4

Ground Activities

All activities were completed unless otherwise noted.

N3 MCA Manual Calibration

MISSE Install in Dragon Trunk

RRM Install in Dragon Trunk

2A1 and 3B1 Battery Capacity Test

Three-Day Look Ahead:

Wednesday, 03/15: Dragon Cargo Transfer, Auxin Transport, NanoRack Science Box 2, MERLIN1 Transfer

Thursday, 03/16: APEX, Sample transfers to Glacier/Polar, FCPA Inspection, EVA Loop Scrub, RR Habitat Stow

Friday, 03/17: At Home In Space, Dragon Depart OBT, Dragon Transfers, Rodent Research Stow, PMA3 Leak Check, WVE R&R Prep

QUICK ISS Status – Environmental Control Group: