The trouble with space stations
by Jeff Foust
|“Any one piece of this individually really isn’t all that hard,” Dwyer said. “Connecting them together and building this thing on orbit is hard.”|
So what makes space stations, either in general or the ISS in particular, so tough to build? That was the subject of a panel session last week at the Military and Aerospace Programmable Logic Device (MAPLD) International Conference in Washington DC. The panel, moderated by Launius and featuring current and former NASA employees as well as representatives of the private sector, discussed the reasons why Freedom/ISS in particular has been such a difficult project. Many of those problems have their roots in the technical complexity of such a venture, but, as some panelists discussed, the station’s difficulties have programmatic and managerial origins as well.
To no one’s surprise, some panelists pointed to what they saw as the tremendous complexity of developing a space station out of a large number of disparate components that must be assembled in the harsh conditions of space. William Dwyer, an engineer at NASA’s Johnson Space Center who has worked on both the Freedom and ISS programs, saw that complexity as the main problem with the station. “My argument [is] that’s it’s the sheer magnitude of the task,” he said.
That complexity manifests itself in a number of ways, generally how individual components interact with other station components. “Any one piece of this individually really isn’t all that hard,” Dwyer said. “Connecting them together and building this thing on orbit is hard.” That difficulty, he said, is in part because of the limits of testing components on the ground that are designed to interface with components already in orbit. “There’s no way to do a good, solid face-to-face integration test.”
The gradual assembly of the station also poses engineering problems, according to Dwyer. “Right now I have systems getting old and breaking down, I’m operating nominal systems, and I’m building new systems, all simultaneously, with a reducing engineering staff,” he said. “We staff this like a nominal ‘design it, build it, launch it, operate it’ kind of thing, and it’s not that: we have multiple life cycles of things going on at any one time. And that’s difficult.”
In the case of the ISS, those problems are compounded by the number of international partners—Canada, Europe, Japan, and Russia—involved in the project. Al Diaz, until recently NASA’s associate administrator for science, said that having to deal with a large number of partners, coupled with the long development period for the station, compounded the complexity. “I don’t think that, inherently, space stations are all that hard,” he said. “From a technological standpoint, in fact, if you compare them to some other things that we do, they’re really kind of simple.”
In an effort to quantify the magnitude of difficulty faced by space station developers, Diaz said he developed an algorithm that computes a “factor of difficulty” for various space station projects. According to his algorithm, Skylab has a score of 5 and Mir approximately 10 to 20. The ISS? About 2,500, Diaz said. “I really think that we have taken on an incredible challenge here.”
Some panelists, though, saw the problems experienced by the ISS program as going beyond just technical issues. “The problem I have seen with the space station is that the requirements are constantly in motion,” said Keith Cowing, who worked at NASA’s space station program office in the early 1990s before founding NASA Watch. That, he added, makes it difficult to explain to Congress and the public what the purpose of the ISS is. “You can’t really get your arms around station.”
|On Diaz’s factor of difficulty scale, Skylab was a 5, Mir 10–20, and the ISS 2,500.|
Export control, as governed by the International Traffic in Arms Regulations (ITAR) laws, has become a serious complicating factor as well. The overhead associated with ITAR “is large and it is growing,” said Dwyer. “These things extend the development cycle… considerably.” Space Frontier Foundation co-founder Rick Tumlinson was blunt: “ITAR has to be changed.”
Not surprisingly, some think that NASA is simply not set up to handle a project like this. “We have the wrong people working the wrong system doing the wrong job the wrong way and for the wrong reason,” Tumlinson said. “That’s why space stations are hard.” He added that the agency should be focused on exploration rather than the more mundane work of transportation and construction in low Earth orbit.
While the panelists discussed many reasons why the ISS program has had so many problems, they had few concrete suggestions on what could be done to improve it. One proposal that has been floated off and on over the years has been to privatize the station in some manner, handing it over from the government to the private sector. However, Chris Faranetta, vice president of the orbital space flight program at space tourism company Space Adventures, was critical of that idea. “The thing about the ISS is that it is so big that I really don’t think there is any way that it can be privatized,” he said, adding that the most one could hope for is some kind of hybrid model where governments still pay for most of the station’s operations and allow some degree of private use.
The size of the ISS is a lesson for future station designers, Faranetta believes. His ideal station would be relatively small, consisting of no more than two modules weighing 20–25 metric tons. The station could be placed in orbit in a single launch, “fully operational from Day One.” Such a station would have a relatively short lifetime of five years. That general approach was supported by a number of other panelists, including Diaz, Dwyer, and former astronaut Tom Jones, who all advocated the development of a heavy-lift launch vehicle that could place a complete space station in orbit in just one or two missions.
Other ideas focused on the managerial problems with space station projects. Faranetta suggested that other nations participate on station projects as subcontractors, rather than full-fledged partners, to streamline project management. Cowing said firm requirements are key: “I think all requirements should be carved in stone.”
|“The space station forced NASA to operate 24/7,” said Jones. “If we’re going to explore, they have to be in the space flight business continuously, and it was a major job to bring NASA up to that realization.”|
There is, of course, the question of whether we need a space station at all. “We don’t need a space station to go to the Moon,” Faranetta said. Alluding to the plans first published by Wernher von Braun over a half-century ago that prominently included a space station as a key step in eventual manned expeditions to Mars—a plan that NASA has, more or less, followed to this day—he added that “we need to get past Wernher von Braun dictating space policy.”
The fact is, however, that we have at least a partially complete space station, and NASA, even as it refocuses its energies on a manned return to the Moon, will try to make the best of what it can with the ISS, as some believe the agency already has. “The space station forced NASA to operate 24/7,” said Jones. “If we’re going to explore, they have to be in the space flight business continuously, and it was a major job to bring NASA up to that realization.”
Tumlinson sees a role for a space station—if not the space station—if the goals for sending humans into space are better articulated. “If somebody would stand up and say, ‘We are going to space because the human species should expand into space,’ then that would drive every other decision… Permanence is the context: we go to live, we go to stay, we go to expand. When permanence is the goal, the station becomes a steppingstone out to that goal.”