Expedition 45 astronauts Scott Kelly and Kjell Lindgren are slated to venture outside the International Space Station (ISS) tomorrow (Wednesday, 28 October) for what has been described by NASA as an “ISS Upgrades EVA”, tasked with installing a thermal cover on the Alpha Magnetic Spectrometer (AMS), tying down insulation on a Main Bus Switching Unit (MBSU), installing a Non-Propulsive Vent (NPV) onto the Tranquility node and lubricating one Latching End Effector (LEE) of the 57.7-foot-long Canadarm2 robotic arm. Kelly and Lindgren—both of whom will be embarking on their first career spacewalks—are expected to spend 6.5 hours outside the ISS, with a second EVA currently planned for 6 November to restore the P-6 truss cooling system to its original state, following a series of technical difficulties and EVAs over the past three years. Tomorrow’s spacewalk, designated “U.S. EVA-32”, represents the 32nd excursion in history to be performed out of the station’s Quest airlock with U.S. Extravehicular Mobility Units (EMUs), conducted without a Space Shuttle being physically present.
Since the inaugural STS-88 EVAs by Jerry Ross and Jim Newman, way back in December 1998, no fewer than 188 spacewalks, totaling 1,177 hours, have been undertaken by astronauts and cosmonauts from the United States, Russia, Canada, France, Japan, Germany, Sweden and Italy to assemble and maintain the sprawling, multi-national orbital outpost. Of this number, 109 spacewalks were executed in EMUs, whilst in the presence of a visiting shuttle—lastly during the STS-135 mission in July 2011—and 48 were performed in Orlan-M-class (“Sea Eagle”) suits from the station’s Russian Orbital Segment (ROS), most recently by Expedition 44 cosmonauts Gennadi Padalka and Mikhail Kornienko in August 2015.
The remaining 31 EVAs, between 20 February 2002 and 1 March 2015, have all involved the wearing of U.S. EMUs and have been “staged” out of the Quest airlock, all in the absence of the shuttle. In fact, when Expedition 4 astronauts Carl Walz and Dan Bursch performed “U.S. EVA-1”—on the 40th anniversary of John Glenn’s historic orbital flight—theirs was hailed by NASA as “the first spacewalk from Quest without the presence of a Space Shuttle at the station”. During their 5.5 hours outside, Walz and Bursch undertook critical preparatory work for the S-0 central segment of the Integrated Truss Structure (ITS), deploying electrical cables, removing thermal blankets, securing latches and retrieving tools, and U.S. EVA-1 opened the floodgates for a series of station-based spacewalks for construction and maintenance work on the U.S. Orbital Segment (USOS).
Although ROS-based and shuttle-based excursions consumed the next few months, it was not until 15 January 2003 that Expedition 6 spacewalkers Ken Bowersox and Don Pettit performed U.S. EVA-2, only days before the untimely loss of Columbia. The following two years proved fractured ones, with two-man “caretaker” crews ensuring continuous occupation of the ISS, and only a single Quest-based spacewalk (U.S. EVA-3 in April 2003) took place before the resumption of shuttle operations in the summer of 2005.
Several months later, in November 2005, U.S. EVA-4 marked the first occasion that a Russian cosmonaut (Valeri Tokarev) had participated in a Quest-based spacewalk, and over the following years the frequency and complexity of their tasks broadened. In August 2006, Germany’s Thomas Reiter became the first non-U.S. and non-Russian spacefarer to participate in a Stage U.S. EVA, whilst Sunita Williams became the first woman to do so when she undertook an “unprecedented” trio of Quest-based spacewalks with Expedition 14’s Mike Lopez-Alegria in January and February 2007 to prepare for subsequent shuttle missions to continue expanding the station. When combined with earlier and subsequent Expedition 14 EVAs in Russian Orlan suits, these marked the largest number of spacewalks ever undertaken by an ISS expedition crew in the span of a single month, as well as securing Lopez-Alegria the record for the greatest number of career spacewalks (ten) and Williams the record for the greatest number of career spacewalks by a woman (four). Later that summer, during Expedition 15, cosmonaut Fyodor Yurchikhin and astronaut Clay Anderson performed U.S. EVA-9, one of whose tasks was to prepare the USOS for the arrival of the Harmony node in the fall of 2007.
In the aftermath of Harmony’s arrival, Expedition 16 crew members Peggy Whitson, Yuri Malenchenko and Dan Tani supported no less than five Stage spacewalks—U.S. EVAs-10 through 14—between November 2007 and January 2008 to configure utilities at the new node and prepare for future ISS expansion. With shuttle and ROS-based EVAs occupying the next couple of years, it was not until August 2010 that a trio of difficult spacewalks were performed by Expedition 24’s Doug Wheelock and Tracy Caldwell-Dyson to remove and replace a failed ammonia pump module on the station’s S-1 truss. This was followed by a further three excursions by Expedition 32/33’s Sunita Williams and Aki Hoshide in August, September and November 2012, which handled the removal and replacement of a failing Main Bus Switching Unit (MBSU) and reconfigured and isolated a leak in the ammonia cooling system of Power Channel 2B on the P-6 truss. Williams and Hoshide’s EVAs were the first U.S. Stage-based spacewalks conducted in the aftermath of the retirement of the Space Shuttle fleet.
The following year, 2013, proved a dramatic one, with U.S. EVA-21 performed at short notice by Expedition 35’s Tom Marshburn and Chris Cassidy to inspect and replace a pump flow control subassembly on the P-6 truss, which had shown a visible leakage of ammonia coolant. Then, in July, EVA-22 saw Luca Parmitano become Italy’s first spacewalker, an accolade overshadowed on the curtailed EVA-23, which was curtailed when he experienced a life-threatening intrusion of water into his helmet. Subsequent EVAs were placed on hold, pending an investigation, although in December 2013 it became necessary for Expedition 38’s Rick Mastracchio and Mike Hopkins to perform a pair of EVAs in response to the deteriorating condition of the S-1 ammonia pump module. Another spacewalk, U.S. EVA-26, was performed by Mastracchio and Steve Swanson in April 2014 to replace a failed multiplexer-demultiplexer on the S-0 truss, ahead of a remarkable series of five spacewalks between October 2014 and March 2015—involving U.S. astronauts Reid Wiseman, Barry “Butch” Wilmore, Terry Virts and Germany’s Alexander Gerst—to tend to a multitude of tasks in readiness for the installation of two International Docking Adapters (IDAs) and the Common Communications for Visiting Vehicles (C2V2) infrastructure.
Original plans called for EVA-32 to occur in August 2015 and would have involved Scott Kelly and Kjell Lindgren installing power and data cables from the newly arrival IDA-1 and completing its permanent installation at the forward end of the Harmony node. This would have been followed by EVA-33 in the October timeframe to support the movement of Pressurized Mating Adapter (PMA)-3 from its current perch on the Tranquility node to the space-facing (or “zenith”) port of Harmony. However, none of this came to pass, when IDA-1 was lost in the 28 June failure of SpaceX’s CRS-7 mission and near-term efforts to reconfigure the ISS for its Commercial Crew needs were placed on hold. However, EVAs were not to elude Kelly and Lindgren and, last month, NASA revealed that the duo would perform a pair of spacewalks for maintenance and upgrade purposes, as well as to install a thermal cover on the Alpha Magnetic Spectrometer (AMS).
At a press briefing, held at the Johnson Space Center (JSC) in Houston, Texas, on 22 October, the details of EVA-32 were hammered out in fine detail. Introducing the proceedings, ISS Operations Integration Manager Kenny Todd understatedly highlighted “some challenges this year”—resulting from the loss of CRS-7, as well as Russia’s Progress M-27M in April-May and last October’s failure of Orbital Sciences’ ORB-3 Cygnus—which rendered original plans to stage seven U.S. EVAs in 2015 impossible. However, he stressed that a trio of EVAs were undertaken in February-March and that the “backlog of EVA tasks on the outside of station”, coupled with a clearer insight into the return-to-flight timetables of SpaceX and Orbital Sciences, has opened up a “window” of time to stage EVAs 32 and 33 and complete “work that we could get done”, as part of efforts to accomplish the “long-term sustaining of space station”.
Mr. Todd then handed over to Expedition 45 Lead Flight Director Mike Lammers, who pointed out that a significant amount of the content for the EVAs was finalized after Kelly and Lindgren reached orbit and that they had recently been working through procedures, checklists and a suited “dry run” in the Quest airlock. They will be joined by Japan’s Kimiya Yui, who will serve as the Intravehicular (IV) crewman, helping to orchestrate the EVA and suiting them up, with Russia’s Sergei Volkov offering an extra pair of hands. Tomorrow’s spacewalk will be overseen from the Mission Control Center (MCC) at JSC by Flight Director Greg Whitney and Lead EVA-32 Officer Grant Slusser, with veteran NASA astronaut Tracy Caldwell-Dyson assigned as Capcom.
Explaining that this was his first spacewalk as a lead officer, Mr. Slusser stressed that the tasks for the revised EVA-32 had been assembled in just three months and will call for Kelly—who is designated “EV1” and identifiable by red stripes on the legs of his EMU—to depart Quest first, with Lindgren (“EV2”, clad in a pure white suit) passing out bags. This will negate the need for either astronaut to return to the airlock during the remainder of the EVA. After performing standard “buddy checks” of each other’s suits and tools, the pair will set about their initial tasks, with Kelly carrying the MLI bag for the MBSU work and Lindgren handling the “LEE Lube” equipment.
If tomorrow marks Mr. Slusser’s first outing as a lead EVA officer, then his excitement can only be topped by that of Kelly and Lindgren themselves. “Marvelous miniature spaceship!” Lindgren exulted to his 44,500 Twitter followers, earlier this month, whilst proudly displaying his EMU suit. “A huge thanks to all the engineers, instructors & divers who trained me to use this.” As for Kelly—selected as an astronaut at the very dawn of the ISS era—it promises to be a special moment in the twilight of his spacefaring career. On each of his four missions, he has been surrounded by spacewalking: on the Hubble Space Telescope (HST), on the construction of the ISS and on the maintenance of the vast orbital base which now serves as his year-long home. But until 28 October 2015, he has never been inside a space suit, gone down to vacuum and physically exited his spacecraft. “Getting my game face on for a spacewalk,” he told his 587,000-strong Twitter audience. “Thanks for sticking w/me.”
As Kelly makes his way along the airlock “spur” and along the starboard side of the truss, to reach the MBSU location on ExPRESS Logistics Carrier (ELC)-2 at the junction of the S-1 and S-3 segments, Lindgren will take the Ballscrew Lubricating Tool (BLT) and move it over to External Stowage Platform (ESP)-2 for use later in EVA-32. He will then collect an Articulating Portable Foot Restraint (APFR) from ESP-2 and translate out to AMS, which resides at the Upper Inboard Payload Attach Site on the S-3 truss. Interestingly, the 14,800-pound (6,700 kg) AMS was installed during the STS-134 shuttle mission in May 2011, commanded by Scott Kelly’s twin brother, Mark. Using the APFR for additional handholds and translation points, Lindgren will install and wire-tie a small “wedge” of MLI material between two AMS radiators. Once installed, it will expand—“like a small tent,” said Mr. Slusser—to better protect the radiators. Lindgren will then install small and large MLI blankets over the AMS pumps, which have experienced recent instances of degradation. Elsewhere, Kelly will begin tying down MLI at the MBSU, in order to provide a clear movement path for the Mobile Base System (MBS), which provides a foundation for Canadarm2. He will tie down the “skirt” of the multi-layered insulation, securing eight “tabs” to each of two handrails.
With their respective first tasks concluded, the two spacewalkers will return to the airlock with the APFR and the MLI bags and set about collecting equipment for the next stage of EVA-32. The APFR will be positioned at the ESP-2 worksite and Canadarm2 positioned by Kimiya Yui, in readiness for the LEE Lube task. Lindgren will retrieve a cable bag, containing power (“Purple-White”) and data (“Orange”) cables for future PMA-3 and IDA operations, then translate under the Destiny laboratory and deploy it. He will initially secure and “temp-stow” the forward portion of the cable onto a handrail, before routing the aft section in an aft direction to the Unity node and their connection point. He will route the Orange cable first, then the Purple-White cable at the Harmony node’s zenith Common Berthing Mechanism (CBM), before turning to his next task of installing the NPV into a very tight area close to the port-side end-cone of the Tranquility node. “Kjell’s got the longest arm,” explained Mr. Slusser, “so that’s why we’re sending him.” The NPV was removed by Expedition 42 spacewalker Barry “Butch” Wilmore on EVA-30 in February, in order to provide better clearance for the relocation of the Leonardo Permanent Multipurpose Module (PMM) on 27 May. After several months stored inside the station, the NPV is now being returned to its original location. Lindgren will remove a cover plate, installed by Wilmore, and will secure the NPV back into position with four bolts.
Meanwhile, Kelly will work on the LEE Lube task, focusing on the opposing Latching End Effector (LEE) of Canadarm2 to the one previously “lubed” by Expedition 42’s Terry Virts during EVA-30. The Canadian-built arm has become somewhat “sticky” in the 14 years since its April 2001 launch and has exhibited sluggish tendencies over recent months, causing higher than anticipated electrical motor currents. Lubrication of the LEE was never intended to be done by spacewalkers, so the BLT—which comprises a probe, wire ties and lots of tape—was employed by Virts on EVA-30 and will be employed by Kelly on EVA-32 to apply lubricant from a Grease Gun. Working “in the blind” at certain stages, the men’s work focused upon five portions of the LEE, including the ballscrews, equilization brackets and latch deployment rollers for its four extended latches. The latches will then be retracted, exposing the two linear bearing tracks for Kelly to lube. Fittingly, Flight Director Greg Whitney also oversaw EVA-30 and will undoubtedly translate much of this experience to supervising his second off-the-planet lube job of 2015.
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