NASA has announced that the Obama Administration has approved an extension of operations for the International Space Station (ISS) through 2024. In a media teleconference this afternoon (Wednesday), Associate Administrator for the Human Exploration and Operations Mission Directorate Bill Gerstenmaier described the decision as “tremendous” with far-reaching benefits for the international partnership and for attracting interest from the commercial and private sectors to become involved in research areas from pharmaceuticals to technology and materials processing applications.
Extending the duration of the station’s life has been the subject of considerable discussion and conjecture for several years, and until today’s announcement the official U.S. Government position was to fund the ISS only until 2020. However, in the final months before the retirement of the shuttle fleet, the heads of NASA, the Russian Space Agency (Roscosmos), the European Space Agency (ESA), the Canadian Space Agency (CSA), and the Japan Aerospace Exploration Agency (JAXA) met in Tokyo to discuss the possibility of an extension as far as 2028, which would represent a full 30 years of operations since the launch of the first ISS component in November 1998. In a joint statement, the partners “reaffirmed the importance of full exploitation of the station’s scientific, engineering, utilization and education potential,” a potential which is recognized in today’s announcement.
At that time, the partners added that there were “no identified technical constraints to continuing ISS operations beyond the current planning horizon of 2015 to at least 2020” and that, moreover, “the partnership is currently working to certify on-orbit elements through 2028.” The decision to maintain a permanent U.S. presence aboard the station for at least another full decade goes a significant distance in establishing some middle ground between these two dates. Meeting that target will be challenging, though not impossible. In 2010, ISS Program Manager Michael Suffredini reported that he felt comfortable that the station was structurally capable of supporting human occupants until at least the early 2020s, whilst analysis of relevant factors—including the procurement of spare parts—are expected to be completed by all ISS partners no later than 2016.
Paying tribute to the “tremendous gift the [Obama] Administration has given us,” Mr. Gerstenmaier was keen to stress the positives, despite several media questioners who pressed him on the attitudes of the Europeans and Japanese about extension, the estimated cost increases of the program, and the possibility of working alone with the Russians, should the other international partners choose to pull out. Refusing to be drawn on these issues, and stressing that such decisions were political-level ones, he explained that he expected the partners to support the extension and highlighted the potential advantages both for them and also for the commercial and private sectors. “We have a planning horizon that’s 10 years long,” he pointed out, adding that researchers previously put off by the apparent closeness of the station’s 2020 end-of-life date will be reassured by the new opportunity and a “large avenue” to develop their experiments for more time in orbit.
The decision to extend the ISS to 2024, he said, “changes the way folks see their investment, including the commercial side and the research side.” As a result, Mr. Gerstenmaier anticipated that it will “change the perspective” of NASA’s commercial cargo providers—which comprises SpaceX and Orbital Sciences Corp., under the 2008-signed Commercial Resupply Services (CRS) contracts—and will offer them a broader planning horizon. “The commercial sector now has a larger market to carry cargo to the ISS,” he said. Commercial Crew is also expected to benefit from the extension. Currently, NASA does not anticipate the first launch of U.S. astronauts aboard a U.S. spacecraft from U.S. soil to occur until at least the end of 2017, which previously offered merely three years before the end of ISS operations. That window of time has now been opened well into the first half of the next decade, giving the Commercial Crew providers with greater “business space” to explore their future options. At present, SpaceX, Sierra Nevada Corp., and Boeing are entering the homestretch of the 2012-2014 Commercial Crew integrated Capability (CCiCap) process, completing a series of milestones to satisfy NASA’s requirements for the end-to-end design of their Dragon, Dream Chaser, and CST-100 piloted vehicles.
Mr. Gerstenmaier concluded his remarks by stressing that the ability for humans to remain in the microgravity environment of low-Earth orbit for lengthy periods remains fraught with difficulty and challenge. He said that NASA considers the ISS as a unique facility to examine the performance of the human body in weightlessness and that the agency looks forward to a joint U.S.-Russian year-long expedition by astronaut Scott Kelly and cosmonaut Mikhail Kornienko in 2015-2016. Mr. Gerstenmaier pointed out that issues such as visual impairment, which is thought to be induced by increased intracranial pressure, required further study before NASA could begin planning Beyond Earth Orbit (BEO) missions and the ultimate goal of a manned expedition to Mars in the 2030s. Fifteen long-duration U.S. astronauts between the ages of 45-55 have experienced confirmed visual and anatomical changes in the aftermath of their ISS missions, including optic disc edema, choroidal folds, and increased intracranial pressure, and for some of them these issues have been persistent.
Although he would not be drawn on the issue of the international partners’ response to the decision, it is certainly timely that today’s announcement coincides with the planned meeting of the heads of the respective space agencies in Washington, D.C., this week. It remains to be seen what their reactions will be, but Mr. Gerstenmaier did point out that the launch of Europe’s fifth Automated Transfer Vehicle (ATV-5)—named in honor of the late Belgian astronomer Georges Lemaître—to the ISS in early June 2014 will be the last in the series. However, Europe has already agreed to build the Orion service module for NASA’s Exploration Mission (EM)-1, which will be the first payload of the giant Space Launch System (SLS) booster, tentatively scheduled for December 2017. This strongly suggests that Europe, at least, will be broadly supportive of the extension decision. Japan, too, has much to gain by a long-lived space station program, and Mr. Gerstenmaier explained that NASA was already in discussions with JAXA to acquire three more H-II Transfer Vehicles (HTVs) to launch cargo and supplies after 2015.
Not surprisingly, the mainstream media has been quick to pick up on the financial cost of the ISS extension, with one news outlet highlighting the fact that four more years will consume upwards of $12 billion from NASA’s budget. Having said that, it was also pointed out that the time typically devoted to science by today’s six-member Expedition 38 crew averages about 50 hours per week, as opposed just a 10th of that figure barely six years ago.
Yet aside from the excitement, the fact remains that at some stage the ISS will pass its useful operational lifetime and will be brought back to Earth, its burning chunks raining through the atmosphere in a torrent of debris. Precisely when the ISS will reach the end of its life is unclear, but the strategic planning will move into high gear at least a year ahead of the event. The first objective, according to ISS Program Manager Michael Suffredini in the “ISS End-of-Life Disposal Plan,” submitted to the Aerospace Safety Advisory Panel in October 2010, will be to ensure that required propellant reserves to execute a safe re-entry into the atmosphere are available, to configure the station in a manner which will ensure its controllability during descent, and to dock whatever vehicles are needed to effect the de-orbit process. Then, four days before the end, the station’s perigee—the lowest point of its orbit, currently around 250 miles (400 km)—will be propulsively lowered to the “minimum controllable altitude.” The final coup de grâce will come with a series of engine “burns” from the de-orbit vehicle, which will cause the ISS to “drop as deep as possible into the atmosphere in one orbit” and ensure the effective capture and destruction in the atmosphere of “high-speed, high-Ballistic Number fragments.”
Fragments. This single word chills the spine of many who have invested their lives into the ISS and who have seen that investment bear incredible fruit: a truly international, multi-cultural outpost, permanently occupied for more than 13 years to date and resplendent in terms of technology and aesthetic beauty. The craft which will be responsible for the final “execution” of the ISS has yet to be formally decided, although current consensus favours a series of four Russian Progress resupply freighters, probably docked “radially,” their engines thrusting forward, aft, zenith, and nadir, to “provide additional delta-V and pitch control” and “achieve tactical phasing” for entry interface.
Over the final four days of the space station’s life, by now long since de-crewed, the Progresses will fire together for 30 feet per second (9.1 meters per second), per day, to set up the final phasing and orbit-shaping properties required for a safe and successful destructive dive into the atmosphere. At one stage, it was hoped that the ATV might play a role in the de-orbit plan, but in April 2012 ESA announced that the fifth ATV would be the last in the series. This is a pity, but Progress has a long-proven track record and is deemed the simplest and most cost-efficient option, with the greatest margin for success.
Still, the ISS will come to an end someday … and before that day comes, the Russians have already hinted that they intend to undock their complement of modules and commission them as an entirely new research facility, called the “Orbital Piloted Assembly and Experiment Complex” (“OPSEK” in Cyrillic). A pair of Progresses would transfer the complex—which will probably comprise the Zvezda service module, both the Poisk and Rassvet mini-research modules, the long-delayed (and still unlaunched) Nauka multi-purpose module, together with a possible six-port node and a pair of science power modules—from the station’s present 51.6-degree inclination into an orbit of about 70 degrees. In June 2009, it was announced that the Russians will use the new complex to assemble components for future interplanetary missions, possibly involving not only the Moon and Mars but even Saturn. Notably, one of its key functions would be to provide “medical and biological conditions required for the rehabilitation of interplanetary expedition crews after their return to Earth orbit.”
For now, the outpost’s future has brightened. In the wake of the retirement of the shuttle fleet, SpaceX last month commenced the first of a dozen planned cargo delivery runs by its Dragon craft, and Orbital Sciences is expected to follow suit with its Cygnus vehicle early in 2013. Russian Progresses currently fly four to five times per annum and, dovetailed into the manifest, are six-month-long visits by the European ATV and month-long deliveries from the Japanese H-II Transfer Vehicle.
Plans for a joint U.S.-Russian year-long mission, beginning in March 2015, offer a greater indication than ever before that the station is now on the cusp of being utilized, not only for its scientific potential, but also for its potential as a testbed for demonstrating the technologies and establishing the life science baseline data needed for longer and more difficult missions beyond Earth orbit. Admittedly, missions as far afield as Saturn, with humans, seem a little on the wild side, in view of the current global economic climate and the paltry financial allocations of space agencies around the world.
The opportunities for NASA’s astronauts, including the eight-strong Group 21, selected last year, are also brightened by the extension. With only four opportunities per annum for U.S. astronauts to fly to the ISS, the scarcity of spots aboard Russian Soyuz vehicles in the coming years was always known to be acute. Before and since the end of the shuttle era, numerous astronauts have departed the Astronaut Office for pastures new, and a perusal of NASA’s Astronaut Biographies home page this week indicates that shuttle pilot Jim Dutton has departed the agency and that Kevin Ford—who commanded last year’s Expedition 34—has moved over into non-flying management status. With the exception of a handful of astronauts from earlier groups, the majority of NASA candidates for long-duration expeditions will be drawn from the two classes selected in 2009 and 2013.
Turning to Japan and Europe, both of whom typically have one flight opportunity per year, the future is similarly bright. Of ESA’s six-strong 2009 class, five will have flown by the end of 2015, with the last of their number—France’s Thomas Pesquet—likely to draw assignment for an expedition in the 2016-2017 timeframe. As for JAXA, it currently boasts Koichi Wakata in orbit on his fourth mission and his second long-duration increment, and with a grand total of 222 days’ space time, as of today (Wednesday), this makes him the world’s most experienced non-Russian and non-U.S. spacefarer. His closest ESA rival is Frenchman Jean-Pierre Haigneré, who accrued more than 209 days in orbit on two missions to Russia’s Mir space station in the 1990s, whilst Canada’s record-holder, Bob Thirsk, is slightly further behind at 204 days, spread across two flights. Wakata’s fellow countrymen Kimiya Yui and Takuya Onishi have already drawn assignments for long-duration missions in 2015 and 2016, with Norishige Kanai expected to follow in a subsequent year. Finally, Canada saw its second long-term resident, Chris Hadfield, fly in 2013, and it currently has two unflown astronauts, Jeremy Hansen and David Saint-Jacques, available for future missions. At present, Canada’s next opportunity for an expedition is anticipated in the 2019-2020 period.