LOOKING FORWARD

The Future of the International Space Station and Long-term Spaceflight

BY CRAIG COLLINS

It took 12 years to build in space, and people have lived and worked aboard it continuously since Oct. 31, 2000 – 225 visitors, from 18 different countries, so far. Its crewmembers have logged more than 1,000 hours of extravehicular activity on more than 200 spacewalks. More than 3,000 scientific investigators, representing more than 100 countries, have participated in more than 2,400 studies and published more than 1,400 results. It’s as big as a football field, weighs nearly a million pounds, and is the most expensive ($100 billion) object ever built.

Backdropped by Earth’s horizon and the blackness of space, the International Space Station is featured in this image photographed by an STS- 134 crewmember on the Space Shuttle Endeavour after the station and shuttle began their post-undocking relative separation. Undocking of the two spacecraft occurred at 11:55 p.m. (EDT) on May 29, 2011.

NASA PHOTO

The numbers are mind-boggling enough that citing them almost muddies the historic significance of the International Space Station (ISS). It’s hard to boil down everything that’s happened in low-Earth orbit (LEO) over the last 20 years, though many thoughtful scientists and historians have made the effort. The Center for Knowledge Diffusion, a U.S. nonprofit that promotes educational access, has illustrated, with its ISS Map of Science, the interdisciplinary flow of knowledge spurred by research aboard the station. The map shows connections among fields as diverse as the humanities and social sciences; medical and biological sciences; and engineering, math, chemistry, and physics – a scope unequaled by any research platform, anywhere.

The ISS has changed the world’s ideas about what’s possible in space. In the nearly 18 years during which humans have continuously inhabited LEO, the program has demonstrated the ability for people in spacesuits to assemble large structures in space. In recent years it has revolutionized robotic assembly in space, with external payloads installed and removed via ground-controlled robotics. It continues to foster the creation of a commercial marketplace for space-based services, from research logistics to microsatellite deployment. The scientific and technical accomplishments achieved by the ISS program have already begun to yield benefits for humanity, in forms ranging from new medical procedures to remote sensing tools.

The ISS program’s international partners – the United States, Russia, Canada, Japan, and the 12 member nations of the European Space Agency (ESA) – have achieved what may be the station’s most significant legacy: a tradition of working together on peaceful activity in space. The intergovernmental agreements developed to make the ISS happen are remarkable for their simplicity and agility, allowing relationships to grow and change over time, and they’ve also laid the groundwork for new collaborations in space, such as the European Service Module that will provide navigation, propulsion, electricity, water, oxygen, nitrogen, and temperature control for Orion, NASA’s spacecraft for exploring the solar system.

Artist’s conception of the Orion capsule with the European Space Agency’s service module. Future NASA space exploration will continue to be an international affair, building on the model and relationships forged by the ISS.

NASA IMAGE

According to Joel Montalbano, NASA’s deputy International Space Station program manager, this decades-long tradition of cooperation in space is sturdier than most treaties negotiated on Earth, where relationships are often roiled by the winds of geopolitics. The ISS operates, literally and figuratively, above such concerns. “For example,” said Montalbano, “you see today the U.S.-Russian relationship, at the political level, is not really the greatest. But in operating with our Russian colleagues on the space station, nothing has changed … the physics is the same, whether you’re in the U.S. or Russia, and there is a job to do where people’s lives are at stake, and we work together with our Russian colleagues.”

Joel Montalbano, deputy manager, International Space Station Program at NASA’s Johnson Space Center in Houston.

NASA PHOTO BY KEN SHIFLETT

THE TRANSITION AHEAD

As NASA and its international partners celebrate the ISS’ remarkable 20-year record of innovation and collaboration, they also face a decision point: There is much the ISS can still accomplish in space – and much research yet to be done aboard the station to lay the groundwork for NASA’s and its partners’ crewed explorations of the solar system. At the same time, NASA now spends a little over $3 billion annually on the ISS program, with a significant amount of the cost for commercial cargo and crew.

In a 2014 report titled “Pathways to Exploration: Rationales and Approaches for a U.S. Program of Human Space Exploration,” the National Research Council concluded that within a few years, continuing to fund the ISS at this rate, without an overall increase in the human spaceflight budget, will negatively affect NASA’s schedule of crewed missions to Mars. Both the legislative and executive branches responded to this report by encouraging development of a commercial marketplace aboard the station, with the goal of shifting most, if not all, of the ISS operating costs onto private companies.

In this illustration, a SpaceX Crew Dragon spacecraft approaches the International Space Station for docking. NASA is partnering with Boeing and SpaceX to build a new generation of human-rated spacecraft capable of taking astronauts to the station and expanding research opportunities in orbit.

NASA IMAGE

As of summer 2018, the future of the ISS was an unsettled question between the White House and Congress. The White House’s 2019 budget request, released in February 2018, proposed an end to direct federal funding of the station beginning in 2025. A month later, NASA submitted, as required by Congress, its ISS Transition Report, laying out its plan to transition the station to commercial operations. Congress responded by asking the agency to consider other options, including the extension of ISS operations until 2028 or beyond.

Whether it is a customer or benefactor of the ISS in 2025, NASA will have the same primary objectives for work on the space station, outlined in its Transition Report: to prepare for deep space missions, to maintain global leadership in human spaceflight, to enable a commercial market in low-Earth orbit, and to continue to foster research and development efforts that will benefit life on Earth.

For now, the agency is working to understand what “commercialization” of the ISS might mean.

What, said Montalbano, does all this mean? In an ongoing effort to foster commercial activity in space, NASA has selected 12 companies to study the future of commercial human spaceflight in low-Earth orbit, including long-range opportunities for the International Space Station. The studies will assess the potential growth of a low- Earth orbit economy and how to best stimulate private demand for commercial human spaceflight. The portfolio of selected studies

will include specific industry concepts detailing business plans and viability for habitable platforms, whether using the space station or separate free-flying structures. The studies also will provide NASA with recommendations on the role of government and evolution of the space station in the process of transitioning U.S. human spaceflight activities in low-Earth orbit to non-governmental enterprises. “When the International Space Station was established, we could not have anticipated all of the benefits it would provide,” said Sam Scimemi, director of the International Space Station division at NASA Headquarters. “We’re excited to receive this input from the commercial market and aerospace experts to help shape a future thriving space economy in which companies contract with each other to conduct research and activities in low-Earth orbit.”

THE EMERGING MARKETPLACE IN SPACE

Of course, NASA has already fostered commercial activity in space; it spurred the first privately operated cargo deliveries to the ISS, beginning in 2012, and in August 2018, announced selection of the first group of astronauts to fly privately operated crew vehicles – the SpaceX Crew Dragon and Boeing Starliner – to the ISS, beginning in 2019. Several companies are already operating aboard the station: NanoRacks, the first company to own and market its own hardware and services aboard the ISS, has flown more than 700 payloads, including the deployment of more than 200 microsatellites, for customers from 30 countries. Since April 2016, Bigelow Aerospace has maintained one of the modules berthed to the station, the Bigelow Expandable Activity Module (BEAM), an inflatable pressurized module contributing to the space station habitable volume. BEAM is 10 feet in diameter by 13 feet long. Most of the U.S. segment modules are 15 feet in diameter and between 18 feet (Node 1 Unity or the U.S./ Joint Airlock Quest) and 37 feet (JEM Pressurized Module) long. Russian modules are a minimum of 9 feet in diameter and 15 feet long (Pirs and Poisk), up to 12 feet in diameter by 43 feet long (Service Module Zvezda), A few modules like the Pressurized Mating Adapters (PMAs) and Cupola are a little smaller than BEAM. BEAM was also never really configured for “habitation.” It lacks some provisions like air circulation (ductwork can be brought in temporarily). It was intended as a technical test of an inflatable and can now be used for storage, with astronauts entering only temporarily.

The NanoRacks CubeSat Deployer launches two CubeSat miniature satellites into space.

NASA PHOTO

Bigelow is one of a handful of companies, including Axiom Space, that have floated the idea of sending up their own modules to be berthed to the ISS for a short acclimation period before unberthing and operating in LEO for profit. A privatized ISS, Montalbano said, may be one in which companies “practice on us to get used to operating in low-Earth orbit, and then go away – meaning either that they berth or dock and then leave, or they come up with a Module 2.0 that they launch and fly autonomously.”

The Bigelow Expandable Activity Module (BEAM) berthed to the ISS on the aft port of the Tranquility Node. The BEAM was developed to test the feasibility of inflatable modules in orbit. It was berthed to the station in April 2016, and is expected to stay in place until 2020.

NASA PHOTO

As successful as companies such as NanoRacks, SpaceX, and Axiom are, none is likely to make such a bold move until NASA’s plans for the ISS are known. “It’s costly for them to do it on their own,” said Montalbano. In the near future, NASA may become more of a facilitator than benefactor, helping guide companies through their first experiences in orbit, “and then possibly they can go off on their own for a second or third. That, to me, is another huge benefit of the space station.”

Two events, each currently scheduled for 2019, have the potential to accelerate the pace of both commercialization and research being conducted aboard the ISS: the first privately operated crew transports, by Boeing and SpaceX – each operating spacecraft that can carry four people, compared to the Soyuz spacecraft’s capacity for three – and the addition of the Russian Nauka (Multipurpose Laboratory Module). According to Montalbano, this means the crew aboard the station will grow from six to seven people, with an accompanying increase in the number of hours spent on operations and experiments.

“And the hope is that maybe the commercial industry allows other traffic to come and visit the space station,” he said. “Maybe once we get Boeing and SpaceX flying crews, that opens up opportunities in the next year-anda-half to two years for other companies to fly people to the station.” As an example, Montalbano said, a company may want to send its own investigator to the station to perform a specific biomedical or materials experiment – or a company might just want to fly people up for a week to film some commercials. “We’re still trying to figure out all the opportunities we can generate with the commercial approach we’re trying to transition to,” said Montalbano.

THE LONG HAUL: A GATEWAY TO DEEP SPACE EXPLORATION

Decades ago, as NASA considered the best uses for its new space technologies, the Space Task Group formed by President Richard M. Nixon in 1969 called for biomedical and psychosocial research aboard a space station that would enable long-term human space exploration, and eventually a Mars landing. Today, as the agency’s plans and capabilities for a crewed expedition to Mars become more refined, the ISS remains an important testbed for testing both the technological and human aspects of long-term spaceflight.

The Gateway is planned to orbit the Moon and serve as a communications hub, science laboratory, short-term habitation module, holding area for rovers and other robots, and a jumping-off point for missions farther into space. Gateway will follow the successful ISS model, with the U.S. and international partners joining to build different segments to be assembled in orbit.

NASA IMAGE

A Mars expedition would, of necessity, be an “Earth-independent” mission, different from the ISS mission, which relies on resupply for basic resources such as food, water, fuel, and even breathable air. Just seven years into its utilization phase, the ISS must continue to serve as a testbed for research into how people can stay healthy and serve capably on a mission that will take them no less than 78 million miles, round-trip, for a duration of two years or more.

Life support technologies have improved remarkably over the past 20 years, but several haven’t yet reached Earth-independence levels. ISS oxygen generators work well, but, like the exercise equipment, will need to be downsized. The ability of ISS systems to scrub carbon dioxide from the interior air and to recover water will need to be improved, said Montalbano, before they’re ready for a Mars mission. “We’re not into a solid 90 percent yet on water recovery on the space station, and if you’re going to leave the Earth system, you’re going to want to be better than 90 percent on that.”

In the summer of 2018, a report from NASA’s inspector general pointed to the possibility that the research necessary for enabling long-term spaceflight is unlikely to be completed by 2024.

As of February 2018, research for at least 6 of 20 human health risks that require the ISS for testing and 4 of 40 technology gaps will not be completed by the end of FY 2024 when funding for the station’s operation is scheduled to end. In addition, research into 2 human health risks and 17 technology gaps is not scheduled to be completed until sometime during 2024, which increases the risk that even minor schedule slippage could push completion past the end of that fiscal year. This is due in part to difficulties with characterizing and mitigating the health risks and, for technology demonstrations, obtaining the required funding and on-orbit research time.

NASA astronaut Dan Burbank, Expedition 30 flight commander, exercises using the advanced Resistive Exercise Device (aRED) in the Tranquility Node of the International Space Station. Vital research on human health risks (such as bone loss) during long-term spaceflight, as well as in filling existing technology gaps, continues aboard the ISS.

NASA PHOTO

While the future of the ISS beyond 2024 isn’t clear, the unfinished business of deep-space research has clarified a few things for NASA and its partners. First, regardless of the degree to which operations aboard the U.S. Orbital Segment become commercialized in the coming years, it will be important that this research remains. Studies must be conducted in parallel to preparations for international collaboration on the Gateway, an outpost envisioned as a staging point for explorations of the Moon and eventually Mars.

“We want to continue flying space station until we have our sustained presence in cislunar orbit,” said Montalbano, though he says the future of the ISS may not necessarily involve a continuous human presence. “We have too many examples in our past where you end one program, and then you’re idle for a while before the next program, and that’s really not a good path for human spaceflight.” A hiatus will mean losing not only the sharpness of decision-making both on orbit and on the ground, but also the collective strength cultivated over the last 20 years aboard the ISS. “To me, that unites a world community,” Montalbano said, “and if you’re not flying, you lose that.”

In March 2017, the House Subcommittee on Space hosted a hearing on possibilities for the ISS after 2024. In his testimony, William Gerstenmaier, NASA’s associate administrator for Human Exploration and Operations, said it would be critical to smoothly transition human spaceflight capabilities from low-Earth orbit aboard the ISS, to regular missions of the Orion spacecraft and its Space Launch System into cislunar space. “I think the station plays a pretty critical role,” he said. “We’re going to need some facility in space as we break the tie of the planet and move human presence farther into the solar system.”

Meanwhile, NASA’s ISS program is focused on how to do the work necessary for completing planned space-related research while accelerating the involvement of private-sector partners. Given the reaction of many legislators to the White House’s 2019 budget proposal, complete defunding of the station by 2025 doesn’t seem a sure thing. Many public and private ISS partners think it may take longer than that to create a viable commercial marketplace in low-Earth orbit, which is one of the issues being examined in the studies recently commissioned by NASA.

“One of the responses could be that for the space station to be a viable investment, companies will want to have it in place late into the 2020s,” said Montalbano, “which I think we can do. Right now the work being done easily gets us to 2028. I think we can get to 2030. We’re taking steps today to make sure we remain a platform that’s operational. The goal is to be there for as long as there is a need.”