A previously unscheduled spacewalk on the International Space Station (ISS) has been successfully completed, after Mikhail Tyurin and Mike Lopez-Alegria carried out the six hour EVA-17A to cut lose a jammed antenna on the docked Progress M-58 supply ship.
Despite problems with Tyurin’s spacesuit sublimator – which maintains cooling and regulates humidity – the antenna was cut loose from the handrail it was jammed under, and tied up, allowing the vehicle to vacate the station in April.
**The most comprehensive collection of STS-117 onwards related presentions and mission documentation are available to download on L2 **
The KURS 2AO-VKA orientation antenna failed to stow during last October’s docking of the Progress and needed to be removed to allow the unmanned vehicle to depart the station safely, ahead of the April arrival of the next ISS crew onboard Soyuz.
The spacewalk took around six hours, starting with hatch opening at 5:00am EST (10am UK) and ending nominally at 11:03am EST (16:03 UK). The EVA will boost NASA astronaut Lopez-Alegria’s total spacewalk time to a new record of over 67 hours, second only to Anatoly Solovyev’s 82 hours.
In preparation for the EVA, Russian cosmonaut (Misha) Tyurin successfully concluded the isolation of Progress M-59/24P from the DC1 (Docking Compartment).
‘Progress hatches (TKG-SU & SU-DC1) were closed and vestibule leak checks performed successfully. A contingency undock with automated redock of 24P if required for the EVA could now be performed (backup would be a manual redock with TORU),’ noted Wednesday’s On Orbit Status Report (published daily on L2).
‘The remaining pre-EVA Russian Segment (RS) system reconfigurations will take place Thursday morning. During the clamp removal and vestibule depress, Russian thrusters were disabled and automatic handover to the RS MCS (motion control system) inhibited.’
The main reason for the EVA is to follow up a previous spacewalk conducted by Tyurin, which involved him trying to manually shift the antenna into a safe position. This failed, leading to the decision to remove the antenna completely.
A variety of tools are at his disposal, including a mallet and a general purpose cutter – which arrived on board shuttle Discovery during her stay at the ISS on STS-116 at the end of last year.
The two spacewalkers will have to communicate their progress to controllers on the ground via the voice links, given the EVA will be carried out in Orlan spacesuits, which don’t have the advantage of their US counterparts, which have helmetcams, allowing KU live TV pictures of EVA work. Regardless, the spacewalk will be carried on NASA TV.
According to the latest On Orbit report, the main objectives – and anticipated completion times – are listed below:
Taking photos of GTS (Global Timing System) antenna unit on SM small diameter (RO) (~5:28am);
Retracting/removing Progress M-58/23P KURS 2AO-VKA orientation antenna at SM aft end port, with report & photography (~6:14am);
Completing WAL2 antenna ops on SM (AFU/Antenna Feeder Unit for European ATV PCE/Proximity Communications Equipment: tighten latch, photos) (~7:26am);
Inspection of ASN-M Satellite Navigation hardware along cable routing path, with photography; plus reconfiguring HF connectors on FP18 connector patch panel (~8:44am);
Photography of reflector surfaces on the MVM ‘Visiometer’ internal & external VVT docking target for the ATV (three LSV-M Laser retro-reflectors #1, 2, 3, if lighting conditions permit) (~9:09am);
Swapping SKK-5 material exposure container for SKK-9 at SM aft end, plus photography (~10:00am);
Inspecting Orlans for plume residue; wiping gloves, jettisoning towels (~10:05am)
Mating ‘VTN-Neutron’ payload hardware connectors on SM (~10:20am);
Taking photographs of handrail HR2421 in the SMDP (Service Module Debris Panel) #6 installation area; also photographing the German ROKVISS experiment and TM/TC ‘monoblock’ payload (~10:30am);
Inspecting retention mechanisms & bolted joints on GStM-2 ‘Strela-2’ cargo boom (~10:40am).
Securing EVA tool ‘caddy’ (KPU) inside DC1 (~10:45am);
Transferring & installing two ‘Yakor’ foot restraints on DC1 EVA ladder (~10:52am); and
Ingressing DC1, removing protective ring, closing EV hatch 1 (~11:03am).