Unpiloted visitors are nothing new for the International Space Station. Since August 2000, when Progress M1-3 docked at the aft port of the Zvezda control module, carrying supplies and equipment for the station’s first long-duration crew, almost five dozen robotic spacecraft have been despatched from Baikonur in Kazakhstan, Kourou in French Guiana, Tanegashima Island in Japan and Cape Canaveral in Florida, laden with food, water, mail, clothes, Christmas and birthday gifts, experiments and other supplies. Today’s scheduled launch of Progress M-16M – also known by its NASA nomenclature of ‘ISS-48P’ – looks, at first glance, like another relatively ho-hum cargo mission.
Yet as with so many things in life, first glances are often deceptive.
Progress has a storied history. Its development began in 1973 in response to the anticipated problem of resupplying and refuelling the Soviet Union’s Salyut 6 space station, whose cosmonauts went on to spend more than six months at a time in orbit. Modelled closely on the Soyuz spacecraft, its interior was redesigned to house several thousand pounds of foodstuffs, 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 today’s scheduled flight, no fewer than 139 Progresses have roared aloft. Only one has failed to reach its destination: the unlucky Progress M-12M in August 2011, whose launch vehicle suffered an engine malfunction and re-entered the atmosphere over the Altai region.
In their book Soyuz: A Universal Spacecraft, 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, 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 Dan Tani calling one Progress “the onion express”, as the latest delivery of letters from home and fresh foodstuffs arrived.
That psychological crutch will arrive somewhat differently today. If all goes according to plan, Progress M-16M will thunder into Baikonur’s skies at 3:35 pm EDT, beginning its journey to the space station. However, the similarities with its dozens of predecessors will end there, for it is scheduled to dock at the station’s Piers port at 9:24 pm EDT, that same evening…on only its fourth orbit, and less than six hours after launch. This is unprecedented. Although America’s Skylab crews accomplished rendezvous and docking within nine hours of launch, Progress (and Soyuz) followed a two-day profile, primarily designed to conserve propellant supplies. The goal is to use this new ‘fast-rendezvous’ approach for future Soyuz crewed flights, although Russian flight controllers have noted their intention to revert to a standard profile - docking at 6:14 pm EDT on 3 August – if something goes awry. It has been remarked that such fast rendezvous approaches are infrequently available during the course of the year and arise only every six months or so.
With the arrival of Progress M-16M, the station will play host to no fewer than six visiting vehicles: the two Soyuz-TMA spacecraft, belonging to the two halves of the Expedition 32 crew, together with Europe’s Automated Transfer Vehicle (ATV-3), Japan’s Kounotori H-II Transfer Vehicle (HTV-3) and Progress M-15M. Of these, ATV-3 – named in honour of Italian physicist Edoardo Amaldi – has been present at the aft port of the Zvezda module since the end of March and is scheduled to be de-orbited on 27 August. Unlike Progress, the ATV boasts three times more capacity for bulk liquids and freight: up to 12,000 pounds of dry cargo, up to 1,900 pounds of water and up to 10,000 pounds of propellant. Its pressurised cargo segment is based upon Italy’s Multi-Purpose Logistics Module, but it utilises a Progress-style docking mechanism to berth at the Russian segment.
First launched in March 2008, ATV-1 (‘Jules Verne’) proved enormously successful and spent six months attached to the space station, before it was loaded with unneeded equipment and sent towards a destructive re-entry in the atmosphere. Its success led many to consider it a future mainstay of ISS operations. A second ATV (‘Johannes Kepler’) was launched in February 2011, followed by Edoardo Amaldi a year later. Unfortunately, in April 2012 the European Space Agency announced that only two more ATVs would be flown. These are named respectively for physicist Albert Einstein and astronomer Georges Lemaître and will be launched in February 2013 and February 2014.
If Edoardo Amaldi is the longest-lived visiting vehicle currently berthed at the station, at the opposite end, docked at the nadir port of the Harmony node, is Japan’s HTV-3. Like so many Japanese craft, which traditionally do not bear personal or other names, it is known as ‘Kounotori’, which transliterates approximately to ‘Oriental Stork’ or ‘White Stork’. According to the Japan Aerospace Exploration Agency, this choice came about because the white stork traditionally carried ‘joyful’ things and thus precisely matched the HTV-3’s mandate of delivering essential supplies to the ISS. First launched in September 2009, followed by a second in January 2011, it arrives quite differently from Progress or the ATV. Rather than docking automatically, it approaches the station in steps and is grappled by the Canadarm2 manipulator arm and berthed onto Harmony.
In addition to its internal pressurised volume, the Kounotori possesses an external payload segment, accessible by mechanical arm after berthing. Since the retirement of the Shuttle, it is presently the only visiting vehicle with the capability of delivering large International Standard Payload Racks. When HTV-3 was grappled by astronaut Aki Hoshide last Friday, it marked the first time that a Japanese vehicle was berthed at the station by a Japanese crewman. Its cargo is illustrative of its scope: it ferried a high-tech aquarium aloft, capable of supporting three generations of fish for up to three months, as well as five small CubeSats. One experiment, a data recorder known as ‘i-Ball’, is designed to survive Kounotori-3’s destructive re-entry in early September, parachuting back to Earth and transmitting data for a short period via Iridium satellite.
The coming weeks and months will continue to be an exciting time for ISS visiting vehicles, long after Kounotori and Edoardo Amaldi are gone. The glorious triumph of SpaceX’s Dragon demonstration flight in May has effectively given the private company a green light to press ahead with its first dedicated cargo mission – currently scheduled for launch on 5 October – as part of the $1.6 billion Commercial Resupply Services contract signed with NASA in December 2008. Under the provisions of this contract – which will potentially expand in value to more than $3.1 billion – SpaceX will execute a dozen Dragon missions and transport a total of 44,000 pounds of payload to the station. Equipment in support of these missions, including the DragonEye proximity sensor, control panels and communications gear, arrived at the station aboard the Shuttle in 2009.
In the meantime, SpaceX pressed on with a successful test of its Falcon 9 launch vehicle in June 2010 and, six months later, with the maiden demo of the spacecraft itself, which performed two orbits of the Earth in a textbook three-hour flight. Last December, NASA approved SpaceX’s request to combine the final two flights of its demonstration trio into one mission – dubbed ‘COTS-2+’ – which unfolded with near-perfection from 22-31 May. Current projections call for the first Dragon cargo flight in October to last for about a month, with the spacecraft due to splash down in the Pacific Ocean as the only operational unmanned visiting vehicle capable of returning cargo to Earth.
The second recipient of the Commercial Resupply Services contract, Orbital Sciences, is also expected to despatch a demonstration flight of its Cygnus cargo craft towards the station before the end of 2012. However, such an ambitious schedule may prove unlikely, in view of the fact that the maiden voyage of Orbital’s new Antares booster – which will loft Cygnus – has been postponed from August until at least October. After launch, Cygnus will undertake a three-day rendezvous and perform numerous systems and functionality tests during final approach, before receiving authority to proceed within range of the Canadarm2 robotic arm for grappling and installation onto the nadir port of the Harmony node. Like Dragon, the Cygnus will spend about a month at the station. Unlike its counterpart, though, it is not intended to survive re-entry.
Less than five months remain before the final curtain falls on 2012; the first year in which the presence of the Shuttle is gone and the baton of supplying and sustaining the International Space Station has passed to governmental and private providers of unmanned delivery services. Today’s launch of Progress M-16M and its ‘fast rendezvous’ raises interesting possibilities about the delivery of future astronauts and cosmonauts to the orbiting laboratory within a matter of hours, rather than days, and the plethora of craft travelling between Earth and space make the station’s own future increasingly more secure.
Video Courtesy of NASA