Extending International Space Station operations will give partners in the orbiting outpost a better chance to recover their massive investments, and perhaps add momentum to the White House push to commercialize low Earth orbit (LEO).
That, at least, was the stated hope as President Barack Obama's top space officials announced his intent to keep the space station flying until 2024—four years short of the spacecraft's estimated structural lifetime—at an estimated cost of $3 billion a year.
The four-year extension is far from a done deal, coming as it did with only a one-day notice to Congress and a lot of uncertainty about whether's international partners will be able to follow suit. Money previously programmed to deorbit the station will go for extended operations instead, and initial congressional response was positive. But long-term federal funding is uncertain at best, and the international partnership is feeling the strain, as some member nations look for a faster return on their space spending (see page 20).
Ultimately, it may well be the private sector that determines if the estimated $100 billion spent worldwide on the ISS was worth it. Longer term, the extended service life will give the growing international space-exploration movement more time to test the hardware it needs to move beyond LEO.
“It is allowing us to have a planning horizon that is really 10 years long,” says William Gerstenmaier,'s human-spaceflight chief. “That really changes the way folks see their investment, especially the commercial side.”
With a 2020 deadline, he says, researchers may gain only a year or so of on-orbit operation after spending three or four years getting a microgravity experiment ready. The life extension “opens up a large avenue of research on board the space station,” he said in a brief Jan. 8 telephone press conference.
That research is already starting to bear fruit, with advances in drug research, robotics technology and the life sciences needed to mitigate the health effects of long-term human exploration in deep space (AW&ST July 29, 2013, p. 14). While NASA also is using the station to expand its skills and technology for deep-space operations, including logistics, communications and life support, the spinoff benefits on Earth promise to be a major administration selling point for the longer service life.
“ISS extension will extend the broader flow of societal benefits from research on the Station,” Administrator Charles Bolden and John Holdren, Obama's science adviser, wrote in a joint blog.
It also will allow more time for improvements in the station itself. John Shannon, the former NASA space shuttle program manager who is now ISS program manager for station prime contractor, says the recent repair of a cooling system malfunction demonstrates the station is “robust” and ready to accommodate more users.
The company conducted engineering and logistics analyses that supported the decision to extend ISS service life, he says. The structure, instrumented with wireless accelerometers that measure how it reacts to arriving vehicles, thruster firings and solar-array motion, is fit to operate until at least 2028. The twin 10-ft.-dia. solar alpha rotary joints—too large to replace now that the space shuttle fleet is retired—have been working well since a lubrication problem was resolved in 2008, he says. The joints move the station's huge solar-array wings to track the Sun.
Launch and orbital vehicles available or expected to deliver cargo and crew to the station can support extended operations, Shannon says. However, bandwidth for research data already is in short supply, despite a doubling since assembly was completed, and is one potential shortfall as station utilization increases. Power is another.
Managers are considering an upgrade to Ka-band links to increase data throughput, Shannon says, and are studying ways to take advantage of improvements in solar-cell efficiency. One possibility may be to fold more efficient solar cell blankets to fit in the unpressurized “trunk” on theDragon cargo vehicle, and send station crewmembers on spacewalks to mount them over the existing arrays.
The Dragon and.'s Cygnus are easing into regular commercial cargo deliveries to the ISS (see sidebar), and NASA's international partners continue to provide logistics support as well. The European Space Agency (ESA) will launch one more Automated Transfer Vehicle with a load of supplies, and early talks are underway with Japan to arrange three more H-II Transfer Vehicle cargo missions after 2015. Russian Progress cargo-carriers also will remain in the logistics mix.
Final proposals for U.S. commercial crew vehicles are due this week, with the first flight of at least one targeted for 2017. However, that may slip, so NASA and Russia are gearing up for another buy of Soyuz-capsule seats to stay within the three-year lead-time window for the Russian spacecraft. Overall, Gerstenmaier says, “knowing now that we're going beyond 2020” puts NASA planners in a better posture to get better prices for crew and cargo services.
The White House announcement came as the heads of more than 30 international space agencies gathered in Washington for a private summit organized by the U.S.., in parallel with an International Academy of Astronautics symposium on space exploration. The ISS extension was expected to be a key topic of discussion.
Jan Woerner, who heads the German space agency DLR, lists himself as a long-time supporter of extending ISS operations beyond 2020, and Germany is the largest supporter of station funding within ESA. Although ESA's future course in station funding will not be set until a ministerial meeting early in December, both agencies have entered a preliminary agreement with one of the private U.S. companies developing a commercial crew vehicle for NASA.
Woerner joined Mark Sirangelo, head of Sierra Nevada Space Systems, in announcing a collaboration that could lead to European use of the company's Dream Chaser reusable space plane, and Sierra Nevada's incorporation into future Dream Chaser upgrades of thermal protection, avionics, air traffic management and other technology developed in Europe, particularly during the Hermes and Crew Return Vehicle spaceplane programs.
“It looks like it is really a synergetic approach of different competencies which we can put together,” Woerner says, calling for a broad mix-and-match framework that allows the use of different space systems, regardless of origin, to achieve redundancy.
In the Sierra Nevada/European collaboration, this could include a use of Ariane launchers to carry the Dream Chaser, which is baselined for the Atlas V. It would also provide Germany with additional leverage in its scuffle with France over future European launcher developments.
“Redundancy is one of the most important aspects in space,” Woerner emphasizes. “We all know if a system fails that we have a long time to investigate the cause. Therefore I would say there is not only the use of some technology for the future of the Dream Chaser, but why not also use the launching system from Europe—the Ariane 5 ME—as a launcher, not only Atlas V, to have a combination in that field across the Atlantic.”