My favorite part about the economically dubious space shuttle decision is what the Soviets made of it. These quotes are from Bart Hendrickx and Bert Vis, Energiya-Buran: The Soviet Space Shuttle, 2007.
The Space Shuttle’s military threat
By mid-1975 the reusable spacecraft had moved to the foreground as the next major step in the Soviet manned space program. Based on the evidence currently available, it would seem this decision was made mainly under pressure from the Soviet military community, which was becoming increasingly worried about the military potential of the US Space Shuttle. These concerns seem to have been triggered by several studies made at Soviet research institutes, including TsNIIMash. TsNIIMash specialists came to the conclusion that the Space Shuttle would never become economically viable if it was only used for the goals that NASA officially announced. As TsNIIMash director Yuriy Mozzhorin later said:
“[The Space Shuttle] was announced as a national program, aimed at 60 launches per year … All this was very unusual: the mass they had been putting into orbit with their expendable rockets hadn’t even reached 150 tons per year, and now they were planning to launch 1,770 tons per year. Nothing was being returned from space and now they were planning to bring down 820 tons per year. This was not simply a program to develop some space system… to lower transportation costs (they promised they would lower those costs tenfold, but the studies done at our institute showed that in actual fact there would be no cost savings at all). It clearly had a focused military goal.”
In their opinion the Shuttle’s 30-ton payload-to-orbit capacity and, more significantly, its 15-ton payload return capacity, were a clear indication that one of its main objectives would be to place massive experimental laser weapons into orbit that could destroy enemy missiles from a distance of several thousands of kilometers. Their reasoning was that such weapons could only be effectively tested in actual space conditions and that in order to cut their development time and save costs it would be necessary to regularly bring them back to Earth for modifications and fine-tuning .
A study often cited with respect to the origins of the Soviet shuttle program was performed at the Academy of Sciences’ Institute of Applied Mathematics (IPM). Headed since 1953 by Mstislav Keldysh (President of the Academy of Sciences from 1961 to 1975), this institute had been involved in mission modeling and ballistics computations since the early days of the space program. The IPM studies were conducted under the leadership of Yuriy Sikharulidze and Dmitriy Okhotsimskiy, two of its leading scientists.
The IPM studies focused on the Shuttle’s possible use as a bomber, more particularly its capability to launch a nuclear first strike against the United States. Efraim Akin, one of the institute’s scientists, later recalled:
“When the US Shuttle was announced we started investigating the logic of that approach. Very early our calculations showed that the cost figures being used by NASA were unrealistic. It would be better to use a series of expendable launch vehicles. Then, when we learned of the decision to build a Shuttle launch facility at Vandenberg for military purposes, we noted that the trajectories from Vandenberg allowed an overflight of the main centers of the USSR on the first orbit. So our hypothesis was that the development of the Shuttle was mainly for military purposes. Because of our suspicion and distrust we decided to replicate the Shuttle without a full understanding of its mission. When we analysed the trajectories from Vandenberg we saw that it was possible for any military payload to re-enter from orbit in three and a half minutes to the main centers of the USSR, a much shorter time than [a sub-marine-launched ballistic missile] could make possible (ten minutes from off the coast). You might feel that this is ridiculous but you must understand how our leadership, provided with that information, would react. Scientists have a different psychology than the military. The military, very sensitive to the variety of possible means of delivering the first strike, suspecting that a first-strike capability might be the Vandenberg Shuttle’s objective, and knowing that a first strike would be decisive in a war, responded predictably” .
The report produced by the IPM scientists has never been made public, leaving unanswered many questions about the technical details of such a mission. Apparently, the Russians believed the Shuttle could drop bombs on Soviet territory while re-entering from a single-orbit mission from Vandenberg or by briefly “diving” into the atmosphere and then returning to orbit. As Energiya—Buran chief designer Boris Gubanov writes in his memoirs:
“The studies … showed that the Space Shuttle could carry out a return maneuver from a half or single orbit … , approach Moscow and Leningrad from the south, and then, performing … a “dive”, drop in this region a nuclear charge, and in combination with other means paralyze the military command system of the Soviet Union.” 
What lent this scenario particular credibility from the Russians’ perspective was the Shuttle’s 2,000 km cross-range capability, demanded by the Air Force to enable the Shuttle to return to Vandenberg after a single orbit around the Earth. However, such single-orbit missions from Vandenberg were not considered for a nuclear strike against the Soviet Union, but to quickly service polar-orbiting US spy satellites or even pluck enemy satellites from orbit, barely giving the Russians a chance to detect such operations with their space-tracking means .
Soviet scientists were divided on whether any of these applications were actually feasible, but eventually the pro-shuttle faction convinced Dmitry Ustinov, the Minister of Defense.
Roald Sagdeyev confirms Ustinov’s role in the final decision to build a Space Shuttle equivalent:
“I heard that [Buran] was adopted mainly due to insistence from Ustinov, who had made the following argument: if our scientists and engineers do not see any specific use of this technology now, we should not forget that the Americans are very pragmatic and very smart. Since they have invested a tremendous amount of money in such a project, they can obviously see some useful scenarios that are still unseen from Soviet eyes. The Soviet Union should develop such a technology, so that it won’t be taken by surprise in the future” .
Let’s build a copy now, and find out what it is good for later!