Its days in orbit may be numbered, but Russia’s Pirs docking module will be a busy place over the next few days, with the scheduled departure of the Progress M-18M cargo ship from the International Space Station later today (Thursday) and the arrival of Progress M-20M on Saturday night. The new Progress—also known by its ISS Program nomenclature of “Progress 52”—will carry about three tons of food, water, supplies, and equipment to the station’s incumbent Expedition 36 crew. Launch is targeted from the Baikonur Cosmodrome in Kazakhstan at 4:45 p.m. EDT Saturday (2:45 a.m. local Kazakh time Sunday). Progress M-20M will follow a now-standard “fast rendezvous” profile and is expected to dock with Piers about six hours later.
By this point, the 16-foot-long Piers—which mounted to the “nadir” (or Earth-facing) port of Russia’s Zvezda service module—will have been empty for a little more than two days. Progress M-18M is due to undock at 4:43 p.m. EDT Thursday and will perform a destructive atmospheric re-entry, concluding a 5.5-month mission which began on 11 February. Among its cargo, the new Progress will likely carry replacement parts for the U.S. space suit which experienced a malfunction during last week’s EVA-23. Scheduled to dock with Piers at 10:29 p.m. EDT, a little under six hours after launch, Progress M-20M will be the fourth of its kind to pursue a fast rendezvous profile. The technique was first trialed by Progress M-16M in August 2012, and its success allowed it to be subsequently performed by Progress M-17M last October and Progress M-18M in February 2013. Only Progress M-19M was forced to revert to the old-style, two-day rendezvous profile, after suffering a glitch with its Kurs rendezvous instrumentation shortly after launch in April 2013.
Saturday’s launch of the new Progress will be the first flight from Baikonur since the 1 July explosion of a Proton-M rocket seconds after liftoff. Quoted by RIA Novosti, Vladimir Popovkin, head of the Russian Federal Space Agency, said on 5 July that “preparations for the Progress launch are running according to schedule.” Progress M-20M itself was transferred to Baikonur’s Spacecraft Assembly and Testing Facility on 17 July for final checkout, and integration of the payload shroud was completed last weekend. The cargo ship was installed aboard its Soyuz-U booster on Wednesday, 24 July, and rollout of the vehicle is currently scheduled for Friday.
Following its insertion into low-Earth orbit (LEO), Progress M-20M will deploy its solar arrays and navigational antennas to establish itself on a four-orbit rendezvous profile to reach the ISS.
The spacecraft—which is part of a family of Soyuz-derived vehicles, whose heritage as space station cargo-haulers stretches back to the late 1970s—will be guided toward a docking at Pirs, under the close watch of cosmonauts Pavel Vinogradov, Aleksandr Misurkin, and Fyodor Yurchikhin.
After standard pressure and other checks, the hatches will be opened and the six-member Expedition 36 crew, which also includes NASA astronauts Chris Cassidy and Karen Nyberg, together with Italy’s Luca Parmitano, will begin the process of unloading the cargo ship.
Progress has a storied history. Its development began in 1973 in response to the anticipated problem of resupplying and refueling the Soviet Union’s Salyut 6 space station, whose cosmonauts went on to spend more than six months at a time in orbit. Modeled closely on the Soyuz, its interior was redesigned to house several thousand pounds of food, water, experiments, and fuel for the station’s manoeuvring thrusters. Since its maiden voyage, Progress has seen many changes, but its role has remained largely unchanged … and the numbers speak for themselves. Between its first launch in January 1978 and Saturday’s scheduled flight, no fewer than 143 Progresses have roared aloft. Only one has failed to reach its destination: the unlucky Progress M-12M in August 2011, whose Soyuz-U rocket suffered an engine malfunction and re-entered the atmosphere over the Altai region.
In their book Soyuz: A Universal Spacecraft, historians David Shayler and the late Rex Hall speculated that the term “Progress” may have originated from the implication of having made significant progress in space station operations—which it certainly did—although the precise heritage of the name remains unclear. What is clear, though, is that aside from the technical and functional role of Progress over the decades, it has provided an indispensable psychological crutch for dozens of cosmonauts and astronauts; a crutch which has enabled them to overcome the profound isolation of the strange microgravity environment, far from family and friends.
Writing in 1998, NASA astronaut Jerry Linenger recounted the sheer joy of receiving a shoebox full of goodies from his wife and children. “Once found, and munching on fresh apples that had also arrived in the Progress,” he wrote in his memoir, Off the Planet, “we individually retreated from our work and sneaked off to private sections of the space station, eager to peruse the box’s contents.” Fellow astronaut John Blaha once described similar excitement: “Once we found our packages,” he wrote, “it was like Christmas and your birthday, all rolled together, when you are five years old. We really had a lot of fun reading mail, laughing, opening presents, eating fresh tomatoes and cheese.” In more recent times, ISS crew members have done much the same. In February 2008, Peggy Whitson, commander of Expedition 16, remembered crewmate Dan Tani calling one Progress “the onion express,” as the latest delivery of letters from home and fresh foodstuffs arrived.
Original planning called for Progress M-20M to be the final flight to dock with Pirs, which has long been intended to be removed from the Zvezda nadir port and deorbited to make room for Russia’s forthcoming Nauka Multi-Purpose Laboratory Module (MLM). It was expected that Progress M-20M would undock with Pirs, after which the two linked spacecraft would perform a destructive re-entry together. However, the long-delayed MLM now seems unlikely to be launched before April 2014 at the earliest, and it is probable that another Progress—the M-22M, scheduled to blast off early in February—will perform the Pirs deorbit operation. The departure of Pirs will make it the first long-term ISS module to be decommissioned and deorbited. Launched in September 2001, it has provided a single docking port for Soyuz or Progress and carries the necessary provisions to support EVAs in Russian Orlan-M space suits.
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