STS-132: Russia’s MRM-1 installed – Port Wing clearance boost
Russia’s Mini Research Module-1 (MRM-1) “Rassvet” has been successfully docked and installed on to the Russian segment of the International Space Station (ISS). Meanwhile, the Mission Management Team (MMT) are close to clearing Atlantis’ Thermal Protection System (TPS) for Entry, after additional imagery of her Port Wing was acquired during EVA-1.
As the crew proceed through Flight Day 5, the mission continues to track the pre-planned timeline, along with the benefit of additional time being released by the confirmation no Focused Inspection (FI) is required – based on the opening evaluations by the Damage Assessment Team (DAT).
“STS-132: On-Orbit: Flight Day 4 Activities Completed: EVA-1 by Reisman and Bowen to install the back-up Space-to-Ground antenna on the Z-1 truss and install a new tool platform on the Dextre Robot,” outlined the NASA Test Director (NTD) update (L2).
“Flight day 5 Activities Planned: Unberth Russian Rassvet module from Atlantis PLB (Payload Bay) and install on the Earth-Facing port of Zarya module. Canadarm Unberth OBSS (Orbiter Boom Sensor System) and hand-off to RMS (Remote Manipulator System). EVA 2 preps, procedure review and campout by Bowen and Good.
“Cryo Margins: (above 12+0+2) O2 limited 29 hours. Transfer Status – end of FD3 report: Middeck Resupply status 80 percent complete. Middeck Return status 21 percent complete. Overall: Ahead of schedule at 48 percent complete.”
The Mission Evaluation Room (MER) have only added a light bulb failure and laptop communication issues associated with the Wing Leading Edge Sensor data to their items of interest – which remains a very short list.
Atlantis herself remains in great condition, with no new issues of note referenced over the past 24 hours. A slight issue with Fuel Cell 3 has not been deemed a worthy addition to the MER “funny” list, with subsystem performance classed as nominal.
STS-132 Specific Articles: https://www.nasaspaceflight.com/tag/sts-132/
“The PRSD O2/H2 manifold 2 isolation valves were cycled closed for crew sleep at 136:23:06 GMT and reopened at 137:07:58 GMT. The second on-orbit purge was performed, beginning at 137/12:06 GMT. During the 45.5 hour purge interval the approximate performance decay was 0.2 Vdc for fuel cell 1, 0.2 Vdc for fuel cell 2, and 0.18 Vdc for fuel cell 3,” added a MER Shift Summary (L2).
“Fuel Cell 3, s/n 118, O2 flow meter indication continues to be erratic. Fuel Cell 3 alternate line temperature has had indications of some trickle flow down the alternate line during the periods when supply H2O tank A is near 100 percent quantity.”
SRMS EE Survey/Port Wing Clearance:
With extensive plans being drawn up for what is in fact a relatively simply EVA task to free a cable that is obstructing the movement of the OBSS PTU (Pan/Tilt Unit) – full outline article will be published ahead of EVA-2 – the MMT are also closing in on potentially scrubbing plans to use the SRMS EE (End Effector) camera to survey part of Atlantis’ Port Wing.
Both the OBSS and the Port Wing evaluations are related, following the PTU’s inability to position the LDRI (Laser Dynamic Range Imager) sensors into a correct alignment with a strip of the RCC (Reinforced Carbon Carbon) during Flight Day 2 inspections.
Managers immediately called on additional assets to acquire photography of the Port Wing, notably during Flight Day 3’s approach and RPM “underneath” the orbital outpost – with two additional ISS crewmembers armed with 800mm cameras. All of the additional imagery has since been downlinked to DAT engineers on the ground.
The only issue with the RPM imagery came via shadowing by Atlantis’ Payload Bay Doors, which obscured the light source (of the sun) on several Port Wing panels, reducing the quality and resolution of the photographs.
Several options were presented, such as taking images from the Cupola module – however, such viewpoints would limit imagery to just “zone five” of the Port Wing.
The main option continued to be the use of the camera on SRMS’ EE, which would provide all of the required imagery. A summary of the procedure shows an impact to the schedule of around 2-3 hours, had it of been added after the MRM-1 installation task.
However, the task on FD5 was postponed due to the late finish of EVA-1 and the concentration on ensuring the MRM-1 docking and installation tasks were carried out without any squeeze on the day’s timeline.
“Planning: EE Survey added to FD5 after MRM Docking. Assumption: EE Survey activity may begin after MRM hooks have closed (~final 1 hr 15 min of MRM activity – Robo 1.101). Survey must be performed in daylight,” noted on of several MMT presentations on the options (L2).
“Three options presented by OPO were assessed by PDRS to determine duration of inspections. OPO (Orbiter Project Office) Option 1 = Stbd RCC, Port RCC, and Port Chine – Estimated time for completion = 2:45. OPO Option 2 = Port RCC and Port Chine – Estimated time for completion = 2:32. OPO Option 3 = Port RCC – Estimated time for completion = 2:20.”
Interestingly, the need to carry out the survey later in the mission may not be required, thanks to the work of the spacewalkers on EVA-1, who provided all the required imagery from the missing coverage on the Port Wing.
“Additional hand held imagery from crew EVA obtained missing coverage associated with port side chine tiles – images reviewed and no issues identified – no additional imagery required,” noted a MER shift report on FD5’s morning update. “TPS plan is to officially clear everything at OPO/MMT.
“RCC: Additional hand held imagery from crew EVA obtained and reviewed: Port panels 1-8 curry zones 6 and 7 went to green (1″ hole criteria area). Imagery analysts will verify resolution. Port panel 1 curry zones 4 and 5 and panels 2-8 curry zone 5 went yellow. Imagery analyst will verify resolution in AM. RCC repair option timelines were discussed and OPO was compiling the inputs for discussion.”
At the time of publishing, the MMT had not decided to remove the option from the docked phase of the mission (will be updated if this changes), with the early Tuesday meetings noting evaluations were continuing on some of the Port RCC panels, although the Chine area had been cleared.
“During the EVA, Garrett took pictures of the PORT Chine. Those pictures cleared that area from further inspection requirements. Pictures of the Port RCC were unfortunately not of sufficient clarity to clear that area,” added the Integrated MMT notes for FD5, although it is understood DAT were close to being satisfied the RCC could be cleared later on Tuesday – as eluded to in the MER shift report.
In addition to the good news about the Port Wing, the opening DAT findings have only noted several areas of cosmetic damage and a few protruding gap fillers.
Nothing unusual has been noted in the FD2 and RPM imagery, although the extensive process of fully evaluating the imagery involves not only an opening look at all the areas of interest, but a peer review – which ensures no mistakes are made with clearing the orbiter’s heatshield for Entry.
Another survey will be carried out during the mission, called Late Inspections, carried out after undocking – although once the PTU on the OBSS has been freed from the cable obstruction, a nominal survey and clearance procedure will be on tap.
Notably, the advances made in reducing foam loss from the External Tanks (ETs) – the main cause of damage on the orbiter’s TPS – has resulted in a long line of ‘clean’ flights. The last notable damage suffered by an orbiter was during STS-118 with Endeavour, although the “gouge” was still cleared for Entry without the need for a repair.
The installation of the Russian module was completed during the first half of Flight Day 5 without issue, despite being a highly complex mix of robotics and communications challenges.
The SSRMS (Space Station Remote Manipulator System) grappled MRM-1 at 5:14 am Central, following the removal of the module from Atlantis Payload Bay via the SRMS (Shuttle Remote Manipulator System). By 5:36 am, Atlantis’ robotic arm released the module, successfully transferring it from one robotic arm to the other.
STS-132 Mission Specialists Garrett Reisman and Piers Sellers maneuvered the station’s arm to deliver the module to its new position on the Russian segment of the space station, an effort which aptly waited for an orbital sunrise to deliver “Rassvet” (“Dawn”) to its permanent home.
Mini Research Module 1 (MRM-1) was manufactured from the residual Dynamic Test Article of the Science Power Platform (SPP). MLM outfitting hardware is mounted externally on MRM1. 1400 kg of NASA cargo launches inside (6.0 m3 of usable on-orbit stowage volume).
STS-132’s tasks associated with this module marked a number of new operations for the shuttle, as outlined in-depth via Flight Readiness Review (FRR) presentations.
“MRM-1 module operations while in Shuttle: MRM-1 module activation in payload bay on FD1 immediately after Post Insertion. MRM-1 is powered by Orbiter via Remotely Operated Electrical Umbilical (ROEU) via PL PRI and CAB PL bus from FD1 to FD5: Provides MRM-1 power for computers, active cooling and Cabin Fan/Smoke Detectors,” noted FRR presentation overviews (L2).
“MRM-1 Command and Telemetry interface provided through Orbiter via Orbiter Interface Units (OIU) /Payload Signal Processor (PSP) and Payload (PL) MDMs. MCC-H (Houston) sends commands on behalf of MCC-M (Moscow) while MRM-1 is in payload bay.”
Following MRM-1’s removal from Atlantis’ Payload Bay via the SRMS (Shuttle Remote Manipulator System), and handoff to the SSRMS, the MRM-1’s Automated Docking System (ADS) was powered up. This occurred once the SSRMS had positioned MRM-1 in the ‘pre-docking’ position – 150cm from the docking interface.
“MRM-1 module operations while on SSRMS: MRM-1 repower on SSRMS will reactivate core systems. MRM-1 Automated Docking System (ADS) will be powered up and the docking probe deployed,” added the overview. “After final interface alignment at 90 cm of docking interface separation, MRM-1 will be translated for final installation.”
Following powerup of the ADS, the MRM-1 docking probe was extended and an internal MRM-1 docking camera was activated – all while the module was attached only to the SSRMS. Crewmembers inside the ISS performed final alignments of the MRM-1 at a distance of 90cm from the docking interface.
This docking procedure was a critical part of the operation, with the potential a serious problem would result in an EVA and the module returning to Atlantis’ Payload Bay.
“MRM-1 docking probe removal in the event of probe retraction failure: In the event MRM-1 cannot be installed and the docking probe cannot be sufficiently retracted, EVA removal of the docking system will be required to return the module to the payload bay,” noted the contingency overview in the FRR materials.
“This contingency case requires multiple failures in a specific and brief period of time; due to this very low likelihood of occurrence, the decision was to establish a contingency plan to determine feasibility of execution but not complete all programmatic analysis required for the activity.
“Plan to put 2 EV crewmembers in APFR/PFR (Foot Restraints) on the Shuttle sill and have SRMS present the module to them for removal of 17 bolts and disconnection (or sever) of three power/data cables. Necessary EVA tools flying on Progress 37 to allow for EVA removal of an MRM-1 docking probe that is failed in a deployed state.
“EV crew members trained on flight hardware (1 g) at RSC-E facility in Moscow. Preliminary PDRS, SSRMS and EVA procedures have been developed and will be submitted in real-time as required. This contingency plan entails open-work associated with hardware tie-down or disposal.”
However, all went to plan, with contact sensors indicating the correct position for installation, allowing the MRM-1 automated docking software to retract the docking probe, drawing the interfaces together, close hooks and handover electrical and data control of MRM1 to the FGB.
Additionally, MRM-1 was the first permanent ISS module to be installed via use of the Robotic Works Station (RWS) in the newly arrived Cupola viewing module – a module brought up to the ISS on the STS-130/20A mission in February of this year.