Polyus (spacecraft) - Development

Development

NPO Energia received orders from the government to begin research on space-based strike weapons in the mid-70s. Even before, the USSR had been developing maneuverable satellites for the purpose of satellite interception. By the beginning of the 1980s, Energia had proposed two programs: laser-equipped Skif and guided missiles platform Kaskad (where Skif would cover the low-orbit targets, Kaskad engaged targets in high and geosynchronous orbits). Together with NPO Astrofizika and KB Salyut, they began developing their orbital weapons platform based on the Salyut DOS-17K frame.

Later, when the objective of ICBM interception proved too difficult, the aims of the project were shifted towards anti-satellite weapons. The 1983 announcement by the US of their SDI program prompted further political and financial support for the satellite interceptor program. In the nuclear exchange scenario, the interceptors would decimate the SDI satellites, followed by a so-called pre-emptive retaliation large-scale Soviet ICBM launch.

The laser chosen for the Skif spacecraft was the 1-megawatt carbon-dioxide laser, developed for the Il-76LL s BL aircraft (an Il-76 flying laboratory with a combat laser), also known as A-60. The introduction of the Energia, capable of launching about 95 tonnes into orbit, finally allowed the ship to accommodate the massive laser. The massive exhaust of the carbon-dioxide laser precipitated the objective of making the laser "recoilless". The zero-torque exhaust system (SBM) was developed to that end. Its testing in orbit meant the release of a large cloud of carbon dioxide, which would hint at the satellite's purpose. Instead, the xenon-krypton mix was used to simultaneously test the SBM and perform an innocent experiment on Earth's ionosphere.

In 1985, it was decided to test-launch the new Energia launch vehicle, which was still in the testbed phase. A 100-ton dummy payload was initially considered for the launch, but in a series of last-minute changes, it was decided that the almost-completed Skif spacecraft would be launched instead for a 30-day mission.

The development of the real Skif was completed in just one year, from September 1985 to September 1986. Testing and tweaking the Energia launch vehicle, the launch pad and the Skif itself moved the launch to February, and then to May 1987. According to Boris Gubanov, the head designer of the Energia launch vehicle, the work schedule of the preceding years was exhausting, and at the point of Mikhail Gorbachev's visit on May 11 he asked the Soviet premier to clear the launch now, because "there will be heart attacks".

The catastrophic malfunction that led to Skif entering the atmosphere in the same area as Energia's second stage was successfully investigated. It was found that 568 seconds after launch the timing control device gave the logical block a command to discard the side modules' covers and laser exhaust covers. Unknowingly, the same command was earlier used to open the solar panels and disengage the maneuvering thrusters. This wasn't discovered because of the logistics of the testing process and overall haste. Main thrusters engaged while the Skif kept turning, overshooting the intended 180-degree turn. The spacecraft lost speed and reverted to the ballistic trajectory.

The launch fulfilled its scientific and testing purposes to approximately 80%, including geophysics and military experiments, research of launching a 100-ton class spacecraft, and data for further development of the Energia/Buran project.