ISS reboosts orbit ahead of STS-117 – Russian spacewalk preps

by Chris Bergin

The International Space Station (ISS) has successfully boosted its orbit to just over 210 statute miles in preparation for Flight Day 3 and 4 rendezvous capabilities with Shuttle Atlantis on STS-117 next month.

The reboost operation was conducted with the use of the docked Progress 25P rendezvous and docking thrusters, which burned for two and a half minutes. Meanwhile, preparations are ongoing ahead of the Russian spacewalk on May 30.

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At present, all appears on schedule for a June 8 launch of Atlantis on STS-117, a mission that will carry the S3/S4 truss segment and solar arrays. The ISS’ reboost is a key step in the preparations for the arrival of Atlantis.

‘A burn duration of 2 min 27 sec, yielding a predicted delta-V of 0.5 m/s (1.64 ft/s) and a mean altitude increase of ~0.86 km (0.46 nmi.),’ noted Wednesday’s On Orbit status report. ‘Purpose of the maneuver is to set up the phasing angle for STS-117/13A launch on June 8.

‘Attitude control authority was handed over to Russian MCS (Motion Control System) at ~6:00pm Eastern for maneuvering to reboost attitude (& back) and returned to US CMG momentum management at ~8:20pm Eastern.’

The next event on the orbital outpost is a spacewalk that will be conducted by Expedition 15 commander Fyodor Yurchikhin and flight engineer-1 Oleg Kotov from Pirs airlock on May 30th.

Tasks involved include the transferring of an adapter with 17 Service Module Debris Panels from PMA-3 to the Zvezda Service Module with using of GStM-2 cargo boom. The temporal installation of adapter with 17 SMDPs onto Zvezda. The installation of five SMDPs (P9, P12, P20, P4, P5) from the bundle No. 4 onto Zvezda, and the replacing of failed high-frequency cable of ASN-M Satellite Navigation Equipment (for ATV arrival) on Zvezda.

Get ahead tasks were ongoing on Wednesday In the Docking Compartment (DC1), with Yurchikhin and Kotov continued preparations for the upcoming Orlan dry-run on 5/28 (Monday),

The spacewalkers spent several hours checking out & readying the replaceable components (OTA) and auxiliary gear for their particular Orlan ‘skafandr’ suits.

‘EV1 Yurchikhin will wear Orlan #25 (red stripes) with BRTA-13 telemetry system, EV2 Kotov Orlan #26 (blue stripes) with BRTA-18,’ added the On Orbit status report. ‘Yurchikhin also installed and checked out two new suits lights on his Orlan #26.

‘More Orlan prep activities are scheduled tomorrow (Thursday), in particular Orlan and Orlan interface unit (BSS) liquid/gas separation (‘degassing’) in PkhO & DC1, plus OTA installation on the Orlans. On Friday, there will be more ORU installation, gear configuring, leak checking of BSS and hoses in PkhO & DC1, plus telemetry checkouts for the spacesuits and BSS units.’

The preparation work ahead of a spacewalk is extensive, with the On Orbit status report noting vast amounts of detail regarding the Russian procedures in ensuring their spacewalk duo are ready for the tasks outside of the station.

‘As part of the standard pre-EVA fitness evaluation, Yurchikhin and Kotov both undertook the Russian MO-5 MedOps protocol of cardiovascular evaluation during graded exercises on the VELO cycle ergometer, their first, each assisting the other in turn as CMO (Crew Medical Officer),’ added the report.

‘The assessment, supported by ground specialist tagup (VHF) and telemetry monitoring, uses the Gamma-1 ECG equipment with biomed harness, skin electrodes and a blood pressure and rheoplethysmograph cuff wired to the cycle ergometer’s instrumentation panels.

‘For the graded exercise, the subject works the pedals after a prescribed program at load settings of 125, 150, and 175 watts for three minutes each. Data output involves a kinetocardiogram, rheoplethysmogram, rheoencephalogram and a temporal pulsogram.’

Preparations have been proceeding on the timeline, with Yurchikhin earlier collecting the array of tools required for the spacewalk’s tasks. They included tethers, wire ties, bungees, a hammer, cutter, scissors, a pry bar and the spacewalk tool caddy.

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