Fate of Space Station is in Clinton’s Hands
By the time this FYI is read, the three redesign options for the space station will be in the hands of President Clinton. After several intense months of redesign work at Clinton’s request, on Monday, June 7, NASA presented the final details of the three options and their estimated costs to Clinton’s “Blue Ribbon Panel,” or, more formally, the Advisory Committee on the Redesign of the Space Station. It was the job of the committee, headed by MIT President Charles Vest, to evaluate the options and pass their assessment on to the President. Clinton is expected to announce his choice on June 15.
The decision is not going to be easy; there is no clear winner among the alternatives, known as Options A, B, and C. None of the three, in their human-tended or permanently manned phases, meet the budget targets laid out by presidential science advisor Jack Gibbons at the beginning of the redesign. The three options were supposed to match expenditures of $5 billion, $7 billion, and $9 billion over the 5-year period from fiscal year 1994 through 1998. (In comparison, according to a recent independent cost estimate, the baseline Freedom design was projected to cost between $16.7 billion and $17.6 billion over that time period.) While all three achieve some cost savings, as well as reduced EVA (extravehicular activity) requirements, they all do so at some sacrifice. What is sacrificed varies among the options.
Option A uses Freedom as a baseline, but departs drastically in several areas. At least three truss sections are deleted, a common core module replaces one node and a lab, and the solar array and data management systems are simplified. Option A actually comes in 2 variations, A-1 and A-2. The first employs a piece of military hardware called Bus-1 to provide propulsion, guidance, control and navigation; the second relies on Freedom subsystems. Option B is basically a reduced version of Freedom, with some innovative changes to reduce EVA and costs, but it is still the most expensive and complex option, and requires the most assembly flights (20). Redesign team leader and former astronaut Bryan O’Conner explained the philosophy for Option A as, “If in doubt, change it,” and for Option B, “If in doubt, leave it alone.”
Option C is a radical departure from the Freedom design. Known as the “Big Can,” it has a single cylindrical core section, part of which would be cannabalized from an existing shuttle. One of Option C’s biggest advantages is that it achieves human-tended capability after two assembly flights. Its drawbacks include risking the whole core on a single launch, and the fact that the core provides enough science payload volume that the international modules become virtually unnecessary. Thus Option C is the least popular with the international partners, whose assessment of the redesign notes that “For Option C, the loss of the essential role of the international partners’ modules renders this option unattractive with respect to their current contributions.”
In terms of the science and engineering research intended for the station, the reviews are mixed. For example: because of structural changes, in both Options A and C the entire vehicle would need to rotate at given intervals to maintain sufficient sunlight on the solar panels, resulting in both variable power supply and regular interruption of the microgravity environment. On the other hand, Option C is rated highest for life sciences research because, requiring the least maintenance, it frees up more time for crew to act as research subjects.
All three options hope to achieve significant savings through changes to the NASA management structure. While many changes are unique to each option, all recommend going to a single prime contractor (the current structure has three), reducing the NASA workforce from 2,300 to 1,000, cutting contractor employees from 17,000 to about 12,000, and streamlining the chain of command.
The last step in the redesign process was setting cost figures for each option. The options were costed at 4 stages: a stripped down “Power Station” (for A and B) in which an attached shuttle would provide temporary lab and habitation space; Human-Tended, in which lab but not hab space would be available on the station; International Human-Tended, when the international modules are added; and Permanent Human Presence, when the station could be permanently inhabited. NASA, which has been criticized in years past for overly-optimistic estimates, made an effort to inject a considerable amount of realism into its cost figures. Significant cost reserves for each stage of growth were included, and 6 months leeway was factored in to each schedule. In another departure from NASA tradition, the figures include more thorough costs for research, operations, and shuttle modifications. However, according to cost team leader Malcolm Peterson, his team “assumed program funding stability.”
The costing was completed just in time for presentation to the advisory committee, with the following results: only the A and B “Power Station” configurations fall within the range specified by Gibbons. For any configuration leading to ultimate human habitation, the costs for the FY1994-98 time period are: $11.9 billion for Option C, $12.8 billion for Option A-2, $13.3 billion for Options A-1 and B. NASA also projected costs through Permanent Human Presence (PHP), and for an additional 10 years of operations. The costs are summarized below (in billions):
Period Freedom A-1 A-2 B C
94-98 $16-17.6 $13.3 $12.8 $13.3 $11.9
94-PHP 25.1 17.0 16.5 19.3 15.2
94-PHP+10 56.7 35.7 35.2 38.3 29.4
None of these costs include the estimated $11.5 billion that will have been spent on the space station through the end of fiscal year 1993.
Still an open issue is the question of the station’s orbital inclination. All costs were based on an orbit of 28.8 degrees, as planned for Freedom. However, NASA is also considering a higher inclination, within reach of Russian, European and US expendable launch vehicles and preferrable in the case of an emergency bail-out from the station.
Later in the week, NASA officials twice appeared on Capitol Hill to testify on the redesign. FYIs #74 and #75 will provide more details.
