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Space Station Freedom
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Space Station Freedom was the name given to NASA's project to construct a permanently manned Earth-orbiting space station.
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Encyclopedia
Space Station Freedom | Artist view |
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| Mission Name: | | | Call Sign: | | | Launch: | 1996-03-01 | | Reentry: | | | Crew: | 4 | | Total power (kW): | 68.3 | | Total assembly flights: | 20 | | Apogee: | 400km | | Perigee: | 400km | | Period: | | | Inclination | 28.5 deg | | Habitable volume (m3): | 878 | | Orbital Mass: | | | Space Station Freedom project |
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Space Station Freedom was the name given to NASA's project to construct a permanently manned Earth-orbiting space station. Although approved by then-president Ronald Reagan and announced in the 1984 State of the Union Address, Freedom was never constructed or completed as originally designed, and after several cutbacks, the remnants of the project became part of the International Space Station.
Original proposal
In the early 1980s, with the space shuttle completed, NASA proposed the creation of a large, permanently manned space station, which then-NASA-Administrator James M. Beggs called "the next logical step" in space. In some ways it was meant to be the U.S. answer to the Soviet Mir. NASA plans called for the station, which was later dubbed Space Station Freedom, to function as an orbiting repair shop for satellites, an assembly point for spacecraft, an observation post for astronomers, a microgravity laboratory for scientists, and a microgravity factory for companies.
Reagan announced plans to build Space Station Freedom in 1984, stating: "We can follow our dreams to distant stars, living and working in space for peaceful economic and scientific gain".
Design iterations
Following the presidential announcement, NASA began a set of studies to determine the potential uses for the space station, both in research and in industry, in the U.S. or overseas. This led to the creation of a database of thousands of possible missions and payloads; studies were also carried out with a view to supporting potential planetary missions, as well as those in low-earth orbit. Several Space Shuttle missions in the 1980s and early 1990s included spacewalks to test and demonstrate space station construction techniques. After the establishment of the initial baseline design, the project evolved extensively, growing in scope and cost.
"Power Tower" (1984)
In April 1984, the newly established Space Station Program Office at Johnson Space Center produced a first reference configuration; this design would serve as a baseline for further planning. The chosen design was the "Power Tower", a central keel with a cluster of five modules at the lower end and a set of articulated solar arrays at the upper end. It also contained a servicing bay. In April 1985, the program selected a set of contractors to carry out definition studies and preliminary design; various trade-offs were made in this process, balancing higher development costs against reduced long-term operating costs.
Dual-keel design (1986)
In March 1986, the System Requirements Review modified the configuration to the "Dual-Keel" design, which moved the modules to the central truss—placing them at the center of gravity, providing a better microgravity environment—and increased the amount of truss structure, with two large "keels". As the international involvement became more organized, the number of U.S. lab modules was reduced from two to one, taking into consideration the provision of space in the European and Japanese modules. Following this, the design was extensively "scrubbed" to remove inefficiencies; this led to a large number of subsystems being revised or removed, the deferral of plans for an Orbital Maneuvering Vehicle to be based at the station, and the use of only a single habitation module for a crew of eight.
In May 1986, NASA produced a report which had studied the assembly sequence with the intent of providing early "man-tended" capacity, ensuring that at an early stage, despite the station not being able to support a crew, research work could be carried out by occasional visiting Shuttle flights. Following the Challenger accident, a Critical Evaluation Task Force was set up to reassess the validity and safety of the Station design. While this validated the use of the Dual-Keel design, post-Challenger safety concerns lead to changes in the assembly plans, as well as assorted minor changes. Johnson Space Center had previously expressed misgivings about the amount of EVA work needed to assemble the station, which were addressed, as were the Shuttle-payload reductions stemming from safety improvements post-Challenger.
In September 1986, a major cost review of the program was undertaken from the post-Challenger baseline; this review was intended to ensure that NASA had a solid basis for its commitment to cost and schedule. The review found that the total development cost for the Dual-Keel configuration would cost US$18.2 billion (in FY1989 dollars), and a slip in the first-element launch (FEL) date from January 1993 to January 1994.
Revised Baseline Configuration (1987)
At the same time, late 1986, NASA carried out a study into new configuration options to reduce development costs; options studied ranged from the use of a Skylab-type station to a phased development of the Dual-Keel configuration. This approach involved splitting assembly into two phases; Phase 1 would provide the central modules, and the transverse boom, but with no keels. The solar arrays would be augmented to ensure 75 kW of power would be provided, and the polar platform and servicing facility were again deferred. The study concluded that the project was viable, reducing development costs while minimizing negative impacts, and it was designated the Revised Baseline Configuration. This would have a development cost of US$15.3 billion (in FY1989 dollars) and FEL in the first quarter of 1994. This replanning was endorsed by the National Research Council in September 1987, which also recommended that the long-term national goals should be studied before committing to any particular Phase 2 design.
During 1986 and 1987, various other studies were carried out on the future of the U.S. space program; the results of these often impacted the Space Station, and their recommendations were folded into the revised baseline as necessary. One of the results of these was to baseline the Station program as requiring five shuttle flights a year for operations and logistics, rotating four crew at a time with the aim of extending individual stay times to 180 days.
Freedom (1988) to Alpha (1993)
NASA signed final ten-year contracts for developing the Space Station in September 1988. The project was finally moving into the hardware fabrication phase. The Space Station Freedom design was slightly modified in late 1989 after the program's Fiscal 1990 budget again was reduced—from $2.05 billion to $1.75 billion.
Repeated budget cuts had forced a postponement of the first launch by a year, to March 1995. The Station would be permanently manned from June 1997 onwards and completed in February 1998.
The 1990 Space Exploration Initiative called for the construction of the Space Station Freedom.
The Space Station Freedom project collapsed in 1990, when the design was found to be 23% overweight and over budget, too complicated to assemble while providing little power for its users. Congress consequently demanded yet another redesign in October 1990 while requesting further cost reductions as the fiscal 1991 budget was cut from $2.5 billion to $1.9 billion. NASA unveiled its new space station design in March 1991.
Cost escalation of the project and financial difficulties in Russia led to a briefing of NASA by NPO Energia on Mir-2. In November 1993 Freedom, Mir-2, and the European and Japanese modules were incorporated into a single International Space Station.
Station program placed on hold
Underestimates by NASA of the station program's cost and unwillingness by the U.S. Congress to appropriate funding for the space station resulted in delays of Freedom's design and construction; it was regularly redesigned and rescoped. Between 1984 and 1993 it went through seven major re-designs, losing capacity and capabilities each time. Rather than being completed in a decade, as Reagan had predicted, Freedom was never built, and no Shuttle launches were made as part of the program.
By 1993, Freedom was politically unviable; the administration had changed, and Congress was tiring of throwing yet more money into the station program. In addition, there were open questions over the need for the station. Redesigns had cut most of the science capacity by this point, and the Space Race had ended with the fall of the Soviet Union. NASA presented several options to President Clinton, but even the most limited of these was still seen as too expensive. In June 1993, a bill to cancel the Station program failed by one vote in the House of Representatives. That October, a meeting between NASA and the Russian Space Agency agreed to the merger of the projects into what would become the International Space Station.
Some historians record Freedom as being a failed project that lacked direction. However, by the time it was replaced by Alpha—derisively dubbed "Space Station Fred" playing on a truncation of "Freedom"—(later the International Space Station), the program had a firm plan, design of most components (with the notable exception of the Crew Return Vehicle) was finalized, and a large amount of flight hardware had been constructed. Had political support remained, it is likely that Freedom would have been launched in the same timeframe as the ISS, and reached a complete (four-man) configuration around 2003–2005.
Conversion to the International Space Station
In 1993, the Clinton administration announced the transformation of Space Station Freedom into the International Space Station (ISS). NASA Administrator Daniel Goldin supervised the addition of Russia to the project. To accommodate reduced budgets, the station design was scaled back from 508 to 353 square feet (47 to 33 m²), the crew capacity of the NASA-provided part was reduced from 7 to 3 (while the complete station will still be manned by 6 in its final stage of expansion), and the station's functions were reduced.
See also
External links
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