The International Space Station is a case where a half a loaf isn't better than none
It's the last stop before Mars. It's a US $113 billion white elephant. It's a cutting-edge research laboratory. It's a 186-ton parasite, leaching funds from real science projects. It's a shining model of international cooperation. It's an empty exercise in foreign policy.
It's the International Space Station. Decisions made about it in the coming months will determine which of the above descriptions apply—and dictate the future of human space exploration for a generation.
The publication of the Columbia Accident Investigation Board's report in August [see ”How to Fix the NASA Disaster”] has provoked a searching debate on human space exploration: after 30 years of futzing around, the United States must finally decide what it wants to do in space--and whether it's ready to foot the bill. The current mismatch between vague feel-good national aspirations and the funding required to seriously explore space has already contributed to the deaths of 14 astronauts and the loss of two $1.7 billion space shuttles.
There are those who believe that human space exploration is pointless and that we should send only robots to the planets. Let them make their case, but if the public believes that human space exploration of the solar system is worthwhile for its own sake--as polls show it has since the dawn of the space age--then space agencies and governments should pursue that goal unapologetically. If taxpayers balk at the price tag, no astronauts should be asked to risk their lives on behalf of a citizenry that refuses to pay for safe and reliable spacecraft.
And the International Space Station is vital to human exploration of the solar system. While some plans for sending people on interplanetary missions completely ignore the space station, such sorties will not depart for several decades. Without developing and operating the space station in the interim, all the accumulated engineering knowledge of how to build and fly manned spacecraft would have to be relearned. We would also have sacrificed the opportunity to learn how to counteract the debilitating side effects of space flight. We must finally commit to do whatever is needed to fulfill the space station's potential as a stepping stone to Mars and beyond--or abandon it tomorrow and retire the astronaut corps.
It's true that the station now appears to be an unlikely candidate for the foundation of humanity's next great adventure. It is currently far from finished and can support a crew of only three. A single Russian Soyuz spacecraft is docked to the station as an emergency lifeboat, and this, more than anything else, is responsible for the three-person limit on crew size--that's all that can fit inside the tiny reentry capsule. Right now, the station can't host even that many people; since the Columbia disaster put shuttle resupply missions on hold, its crew has been reduced to two.
Nevertheless, the International Space Station can yet become a valuable stepping stone to the planets. First, though, three things must happen: we need to establish that supporting exploration, not science, is the No. 1 priority of the station; we need astronauts to stay onboard long enough to find out how to keep them sufficiently fit to explore Mars even after a long interplanetary voyage; and--most important of all--we need to finish the station and staff it with enough crew members to allow us to accomplish these goals.
Here's how to make it all happen.
1. Stop pretending it's all about science
”You build a manned space station for the express purpose of learning how to build an interplanetary spaceship,” says Robert Zimmerman, author of Leaving Earth: Space Stations, Rival Superpowers, and the Quest for Interplanetary Travel. ”Scientific work is great, but just as with Apollo, it's a bonus.”
Regardless of their official rhetoric, governments have always been reluctant to pour significant resources into human space exploration for its own sake: after NASA achieved the Cold War goal of beating the Soviet Union to the moon, its funding collapsed. So, despite its conception as part of an infrastructure for interplanetary exploration, the International Space Station was justified primarily as a platform for pure science and only secondarily as a place to perform biomedical research on the effects of long-duration space flight or to test systems for future interplanetary missions.
As a consequence, debates about the value of the station normally revolve around whether doing research in a weightless, or microgravity, environment is worthwhile. Indeed, similar debates have been going on since Yuri Gagarin's first manned flight in 1961 and have yet to produce a clear consensus.
The final verdict on the scientific merits of the station can come, however, only in hindsight: if a major scientific breakthrough results from some serendipitous observation made onboard, all will be forgiven, but if 10 years go by with little to show, the station's scientific detractors will be entitled to a resounding ”I told you so.” In the meantime, it seems reasonable to invest in one permanent research facility in space with a crew who might chance upon a critical observation that no one thought to program the machines to watch for.
In any case, the he-said-she-said squabbling over the value of microgravity research misses the International Space Station's true worth--and may even be damaging the political support required for adequate funding.
The public is ”generally bored by ill-focused science research,” says Zimmerman, who feels that this lack of interest is contributing to its reluctance to increase government spending on human space flight, despite the broad support for space exploration. Science is ”not what fires the public up,” he continues. ”What fires the public up is the sense that there's real exploration going on. If everyone knew that every module that was going up was leading toward the eventual launching of a spacecraft to Venus or Mars, that would make it a far more palatable and exciting project.”
Quite apart from helping us develop the subsystems and other hardware that will be needed for such a mission, the station will help us learn how to manage the most sophisticated, yet fragile, elements of an interplanetary expedition: people.
2. Start thinking about really long-duration space flight
Barring the invention of a warp drive, traveling between Earth and Mars will take between 180 and 258 days, depending on whether you choose to be a spendthrift or a miser with fuel. Although humans have flown for longer periods aboard Russian space stations (the current record for a single stay is 439 days), there are concerns about the effects of such prolonged exposure to microgravity. Freed from the constant struggle against gravity, muscle and bone quickly atrophy, although astronauts and cosmonauts usually recover fully after several months back on Earth.
But planetary exploration is a grueling physical challenge, as demonstrated during the Apollo lunar expeditions. Will humans actually be able to do any useful work once they arrive on Mars after months of weightlessness?
Zimmerman thinks we need to find out. The Russian long-duration missions, although encouraging, ”haven't yet proved that humans could work on Mars when they get there,” he told IEEE Spectrum. ”Let's find out if we can learn how to keep people strong enough to survive the journey to Mars while weightless and be able to work when they get there.” The other solution, developing a spacecraft that could generate artificial gravity using centrifugal force, would push the expense of a Mars expedition beyond what anyone is likely to pay, he argues.
Currently, International Space Station crews perform 180-day missions, although stays are often prolonged when schedule problems arise. But even then, station occupancies are at the low end of what's required to travel to Mars, let alone return. Stays should routinely extend beyond 180 days--first to characterize exactly what happens to humans in microgravity after such a long exposure, and then to develop biomedical technologies that will alleviate unpleasant side effects. But to conduct these studies properly, the crew size will have to be expanded from three to at least six.
At least two astronauts are required full-time just to keep the station functioning, explains Joerg Feustel-Buechl, director of manned space flight for the European Space Agency (ESA). As a result, even a three-person crew means that ”we would not have enough crew time available for life science-related research.” Beyond just ensuring enough time to perform experiments, larger crew sizes offer another benefit: since crew members normally double up as test subjects, larger crews will allow a statistically significant set of results to be produced in a reasonable time. So far, only 10 men and one woman have flown in space for more than 180 days at a stretch, far too small a population to allow researchers to draw any but the broadest conclusions about what would happen on a trip to Mars. But expanding the size of the crew means finishing the station, and there are some tough obstacles in the way.
The heart of the space station as it now orbits above us is a collection of Russian modules that would have formed Mir II, the successor to Russia's long-lived Mir space station, had the United States and Russia not merged their space station programs--and had the Russians not been broke. The Russian section is connected to the rest of the station by a U.S. module known as Node 1 [see above]. An airlock that permits the crew to perform space walks is attached to its side, and on top is a collection of flywheels that help keep the station correctly oriented in space.
Also attached to Node 1 is the crown jewel of the U.S. section, the Destiny laboratory module. Above Destiny is a short section of the truss that should ultimately stretch the length of two football fields, forming the backbone of a huge photovoltaic array. Part of the array has already been temporarily parked on top of the flywheels, along with a number of heat radiators waiting to be moved into final position. What's missing is the rest of the photovoltaic array, the European and Japanese research modules (called Columbus and Kibo, respectively), another node (Node 2) to join those modules to Destiny, and, most significantly, a life-support system and enough lifeboat seats for a six-person crew.
3. Figure out a way to finish the station
Unfortunately, even before the space shuttle Columbia disintegrated and put the assembly of the International Space Station on indefinite hold, mounting costs raised questions about whether the station would ever be completely finished.
When Columbia disintegrated over Texas, Moscow suddenly found itself at the helm of the International Space Station. Without the shuttle, Russian Soyuz manned spacecraft and Progress automated cargo ships remained the only physical link between Earth and the orbital outpost. The other station partners were suddenly looking to Russia to sustain the bare-bones platform and its crew.
Although the crew could have abandoned the station and returned home onboard the lone Soyuz currently maintained at the station, the permanent occupation of the station is more than a luxury. Decades of Russian experience have shown that without a crew, space stations can easily fall victim to problems that would otherwise be trivial to handle. For example, in 1985 the Russian Salyut 7 space station lost power while in between crews. Dispatched on a difficult and dangerous repair mission, two cosmonauts eventually revived the station and discovered the cause of the power loss: a switching system between the station's solar panels and its rechargeable batteries had failed, something that could have been easily fixed by humans but that nearly spelled the end for Salyut 7.
The challenge in sustaining a crew aboard the International Space Station was obvious: small Russian vehicles had to compensate for the loss of the awesome lift capabilities of the shuttle. The shuttle can carry nine tons of supplies to the station using a European-built so-called Multi-Purpose Logistics Module [see ”Bigger Is Better,”]. In contrast, the unmanned Progress cargo ships can bring about 2.75 tons of material to the station.
But the real showstopper was money. ”If we solve our financial problems, we have no engineering issues that would prevent us from maintaining the station ourselves,” says Yuri Grigoriev, the top engineer at Moscow-based RKK Energia, the Russian company that builds the Soyuz and Progress spacecraft. Russian space officials warned that without financial aid from abroad, they couldn't guarantee an uninterrupted flow of supplies to the station. Even before the Columbia disaster, the cash-strapped Russian space industry was struggling to produce enough resupply ships for routine operations, and the number of Russian supply missions had melted from five or six Progress flights per year to three, with the shuttle filling the void.
Without the shuttle, year-round manned operations onboard the station with only three Progress vehicles would be impossible. By increasing the number of Progress missions to four in 2003 and to five in 2004, Russia could support two people onboard the station without the help of the shuttle.
The Russian space agency, Rosaviacosmos, asked NASA for money to fund the station supply missions, only to be stymied by a congressional ban on any transfer of cash--a punishment for Russia's assistance in developing Iran's nuclear technology.
Then, after more than a decade of severe underfunding had pushed the Russian human space program to the brink of total extinction, a funny thing happened. With oil prices soaring, the Russian economy improved and an unexpected surplus flowed into the Russian treasury. The Russian government had based its projected revenues for 2003 on oil priced at $17 to $19 per barrel, but turbulent events in the Middle East pushed the actual price to $25 per barrel. And so the Russian human space program got help from the least expected source--the Russian government.
After months of intensive lobbying by space industry officials, the Russian parliament, the Duma, gave a bigger slice of the nation's space budget to the manned space program. Some $50 million taken from other space projects was poured into the space station program [see ”Russia Gives International Space Station a Lift,” Spectrum, February, pp. 28-29]. The Russian government agreed to accelerate the release of funds that had originally been allocated for the second half of the year. Even better, it also promised to increase overall funding to $500 million in 2004, from $350 million the year before. The manned space program expects to receive $200 million of that total, almost a twofold increase from 2003.
Russia's willingness to step up to the plate has done much to warm relations between it and the other international partners, which had been strained following lengthy delays in launching Russian-built station modules. ”They are the only ones that can supply the necessary logistics at the moment, and they are doing so in a remarkable way, I must say,” ESA's Feustel-Buechl told Spectrum. Michael Kostelnik, NASA's deputy associate administrator for the shuttle and space station programs, agrees. ”During this crisis, the Russians have shown themselves to be extremely good partners,” he says. ”In spite of the hard financial times, they continue to do the right kinds of things to keep us crewed.”
In the future, the station will have even more resupply options, because a brand-new vehicle is expected to join the station servicing fleet. In September 2004, the first European-built Automated Transfer Vehicle (ATV) is scheduled to blast off from French Guiana on top of an Ariane-5 rocket.
Equipped with Russian docking and refueling mechanisms, the ATV will be able to refuel the station and transfer nine tons of cargo. However, the European ATV is designed to supplement rather than replace the venerable Progress, since the Progress's low cost--approximately $20 million-$60 million per mission, versus the ATV's $200 million-$300 million--and ability to deliver cargo frequently are expected to remain unmatched for the life of the station. Nor can the ATV wholly replace the Multi-Purpose Logistics Modules carried by the shuttle, because the ATV can't mate to the station's larger doors, limiting the size of cargo items that can be transferred.
That said, the international partners are certainly eager to reduce their reliance on the Progress spacecraft assembly line. In a recent letter to ESA, NASA administrator Sean O'Keefe ”encouraged us heavily to accelerate the ATV's development,” says Feustel-Buechl, who told Spectrum that ESA is trying to comply but will probably be unable to accelerate the work significantly. Still, he pledges that ESA is ”doing everything possible to keep our ambitious launch date” in September 2004 and may even be able to shave ”a bit” of time off that schedule.
With the supply situation coming under control, the big question left is how to continue the station's assembly. With the shuttle fleet grounded, all non-Russian elements of the station, including large sections of the station's backbone truss, as well as European and Japanese laboratory modules, are stuck on the ground indefinitely.
NASA now hopes to begin flying the shuttle again as early as March 2004 and immediately resume the schedule of flights to the station. Meeting the return-to-flight requirements of the Columbia Accident Investigation Board, however, may prove more challenging than initially thought. Specifically, in its August report, the board demanded that NASA provide shuttle crews with the capability to inspect and repair damage to the shuttle's fragile tiles and panels, which protect against the heat of reentry. That's a considerably taller order than its other return-to-flight requirements, like redesigning the area on the huge external tank that shed the insulating foam that fatally damaged Columbia.
How long it will take to develop this capability, or indeed if it's possible to do so, is uncertain, leaving large chunks of the station sitting on the ground. At any rate, if the shuttle is out of action for a lengthy period of time--or in the worst case, permanently--a long-shot alternative could still get the station finished.
Within weeks after the Columbia accident, two Moscow-based Russian space industry giants, M.V. Khrunichev State Space Science and Production Center and RKK Energia, proposed to the international partners to launch their elements onboard a specially designed carrier platform, lifted into orbit by a Proton rocket. The Proton is a workhorse that has already been used to launch Russian station modules. A Progress cargo ship would then dock to the platform and bring the modules to the station.
This approach also promises to be cheaper and, since no astronauts would be required to pilot the Proton, safer. The financial savings would be achieved because Protons are a relative bargain at $100 million to $130 million per shot, versus $500 million to $1 billion for a single shuttle mission.
So far, however, the other station partners have rejected the proposal because the station elements concerned, such as the European and Japanese research modules, were designed to be launched on the space shuttle, a NASA spokeswoman said. The space shuttle's human-friendly launch profile allowed the modules to be designed for a gentler ride into space than that provided by the unmanned Proton rocket. Of course, faced with a choice of fitting their modules to a Proton rocket or leaving them to sit unused in a warehouse, the international partners might warm to the Proton option.
Whichever way the station assembly resumes, a major stumbling block remains on the road to a six-person crew: the need for rescue vehicles that can evacuate the crew in an emergency.
The station's cost overruns forced NASA to all but abandon the development of a minishuttle-style crew return vehicle that could serve as a lifeboat for an entire six- to seven-member crew. So, until the United States does provide some form of escape vehicle, there's no alternative to Russian spacecraft for rescuing the crew. ”For now, the only solution is Soyuz,” concedes NASA's Kostelnik.
However, citing the restrictions on cash transfers imposed by Congress, NASA has rejected Russian proposals that it buy a second Soyuz spacecraft that could guarantee the safe return of three additional crew members from the station.
To maneuver out of this dead end, the international partners seem to be embarking on some old-fashioned mutual backscratching. The most likely scenario is that in exchange for such services as flying astronauts and equipment, the other international partners, led by ESA, will buy the needed Soyuz spacecraft from the Russians and give them to NASA, allowing the United States to fulfill its crew rescue obligations without paying the Russians a dime.
The second major challenge that currently prevents the station from hosting a permanent six-person crew is the limitations of its life-support system. The Russian module now responsible for life support provides only enough resources, like oxygen and water, for three people; NASA had originally planned its own habitation module to provide additional life-support capacity for a six-person crew. The habitation module, however, also fell victim to cost overruns.
But following a near revolt in 2002 by the station's scientific community, concerned about the small amount of time available for research with a three-person crew, NASA finally acquiesced to the need for a larger crew. ”Clearly, getting more people onboard is important to utilizing the various laboratories we're going to have up there,” says NASA's Kostelnik.
During a December 2002 summit in Tokyo, all the station partners reconfirmed their commitment to the goal of at least six crew members, and NASA opted for an Italian-built module, known as Node 3, fitted out with additional life-support equipment to fill the habitation module's shoes.
The Node 3 plan has a catch, though. The intended spot for the Node 3 module is located just a few feet from the docking compartment of the Russian-built station control module, used to receive Russian supply ships. According to the original plan, Russia was expected to add a so-called docking and stowage module to the control module's docking compartment, which would give supply ships a new place to park without running the risk of crashing into the side of Node 3.
Unfortunately, as of today the stowage module exists only on paper. But once again, ESA, which appears to have adopted a role not dissimilar to that of horse-trading Radar O'Reilly from the television show ”M*A*S*H,” is likely to come to the rescue. ”As part of the Soyuz procurement, we could make an arrangement,” Feustel-Buechl explains. With the construction of ESA's Columbus research laboratory, the Multi-Purpose Logistics Modules, and two node modules for the United States, Europe has an experienced and functioning production line, he continues. ”We could supply the basic stowage module, [and] the Russians could then equip it with their own equipment” to create a limited science module while they await the launch of their homegrown laboratories.
Indeed, although NASA attached its Destiny laboratory to the station in 2001, and Europe and Japan are completing their labs, the development of the Russian scientific facilities has stalled. Recently, however, editorials in the Moscow press calling Russia a mere ”chauffeur of the ISS [International Space Station]” has prompted the Russian government to act. RKK Energia expects to finally receive funds to build up the Russian segments of the station shortly.
The International Space Station could become a milestone in the history of exploration as significant as Columbus's Santa Maria or Armstrong and Aldrin's lunar lander Eagle. All we need now is the will. The debate ignited by the Columbia disaster report will tell us whether or not that will exists--and whether the seven astronauts who died in the skies above Texas did so in vain. Building the station as a way point on the road to the planets will ensure that they did not.
As this article goes to print, China is conducting final preparations for the country's first manned space mission. Western observers have already begun debating the implications for cooperation--or competition--with the Chinese in human space flight.
Although some predict a new race to the moon between Beijing and Houston, Russian experts who have had a glance into the secretive world of the Chinese space program warn not to expect China's flag on the moon anytime soon. ”They're interested in docking systems and the creation of a Chinese-manned orbital laboratory,” says one such expert, who demanded anonymity because of the sensitive nature of the topic of Chinese-Russian cooperation.
Any initial Chinese space station is likely to be smaller than even the original 13-meter-long Salyut space station launched by the USSR in 1971. Its basic building block will be the detachable orbital module of the Shenzhou manned spacecraft [see above], which is capable of autonomous flight [see ”Taikonauts Prepare for Liftoff,” IEEE Spectrum, December 2001, pp. 42-47].
”Using initially one and later several of such modules, China will build a small station,” says the Russian expert. ”Right now, their most pressing problem is conducting a manned space flight--as soon as they've done that, though, they will be preparing for the docking of two manned spacecraft.” Rendezvous and docking are the key to any advanced space program, and it took the United States and Russia several years after their first manned missions to reach that milestone.
Despite the fears of some U.S. analysts, a Russian-Chinese space alliance is unlikely. ”The Chinese are capable of conducting their space program all by themselves, and they have no intention of involving anybody outside the country. This program is autonomous and has no goal of cooperation,” says another high-ranking Russian space official, also speaking on the condition of anonymity, who recently returned from a trip to China. ”They have some particular issues where they do need Russian expertise. Currently, we have some private agreements--however, they don't directly affect the Chinese manned space program,” he continues, noting that although they based it on the Soyuz, the Chinese developed their own spacecraft. ”Their mentality is everything has to be Chinese.”