Polyus (spacecraft)

Polyus

Cutaway drawing of the Polyus spacecraft
17F19DM
Mission type	Space weapon technology demonstrator
Satellite of	Earth
Orbits	0
Launch date	15 May 1987
Carrier rocket	Energia
Launch site	Baikonur Cosmodrome, Tyuratam, Kazakh SSR
Mission duration	Mission failed
Mass	80,000kg
Dimensions	37m x 4.10m

The Polyus spacecraft (Russian: Полюс, pole), also known as Polus, Skif-DM, GRAU index 17F19DM, was a prototype orbital weapons platform designed to destroy SDI satellites with a megawatt carbon-dioxide laser. It had a Functional Cargo Block derived from a TKS spacecraft to control its orbit and it could fire test targets to demonstrate the fire control system. It was intended to be the first module of the third generation space station, Mir-2, after its failure, Mir-2 was delayed and later incorporated into the International Space Station. Zarya now fulfills that part of the polyus mission, and has no armaments.

Polyus was launched May 15, 1987 from Baikonur Cosmodrome Site 250 as part of the first flight of the Energia system, but failed to reach orbit.

According to Yuri Kornilov, Chief Designer of the Salyut Design Bureau, shortly before Polyus' launch, Mikhail Gorbachev visited the Baikonur Cosmodrome and expressly forbade the on-orbit testing of its capabilities. Kornilov claims that Gorbachev was worried that it would be possible for Western governments to view this activity as an attempt to create a weapon in space and that such an attempt would contradict the country's previous statements on the USSR’s peaceful intent.

For technical reasons, the payload was launched upside down. It was designed to separate from the Energia, rotate 180 degrees in yaw, then 90 degrees in roll and then fire its engine to complete its boost to orbit. The Energia functioned perfectly. However, after disconnecting from Energia, the Polyus spun a full 360 degrees instead of the planned 180 degrees. When the rocket fired, it slowed and burned up in the atmosphere over the south Pacific ocean. This failure was attributed to a faulty inertial guidance system that had not been rigorously tested due to the rushed production schedule.

Parts of the Polyus project hardware were re-used in Kvant-2, Kristall, Spektr and Priroda Mir modules, as well as in ISS Zarya FGB.

Development

NPO Energia received orders from government to begin research on space-based strike weapons in the mid-70s. Even before, USSR has been developing maneuvering satellites for purposes of satellite interception. By the beginning of 1980s, Energia had proposed two programs, laser-equipped Skif and guided missiles platform Kaskad (where Skif would cover the low-orbit targets, while Kaskad engaged targets on 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 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 Skif spacecraft was the 1-megawatt carbon-dioxide laser, developed for the Il-76LL s BL aircraft (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 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 tesbed 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 will 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 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 the 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 atmosphere in the same area as Energia second stage was successfully investigated. It was found that at 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.

Specifications

• Length: 37.00 m (121.39 ft)
• Maximum Diameter: 4.10 m (13.5 ft)
• Mass: 80,000 kg (180,000 lb)
• Associated Launch Vehicle: Energia.
• Intended orbit: altitude 280 km (170 mi), inclination 64°
• Targeting system: optical, radar, with low-yield laser for final targeting
• Armament: 1-megawatt carbon-dioxide laser

See also

• Almaz
• TKS-based spacecraft

External links

• Polyus page (in Russian)
• buran-energia.com Polyus page
• K26 Polyus-Energia page
• Astronautix.com Polyus page
• Polyus and launcher pic