Strela (ISS)

from Wikipedia, the free encyclopedia
The ISS module Pirs with a clearly visible Strela-1 crane (left). At the time of the photo in December 2001, the Strela-2 has not yet been mounted.

Strela ( Russian Стрела for arrow or swivel arm) refers to two Russian cranes on the International Space Station (ISS) .

development

The Strela crane system is based on a similar crane on the Russian Mir space station . The two structurally identical cranes used on the ISS are called Strela-1 and Strela-2, according to the starting order. In contrast to the Canadarm2 robot arm, which is already installed on the ISS, and the planned European Robotic Arm , the Strela cranes are far less complex systems. For example, the movements of the crane arms during outboard operations are controlled directly by a spaceman by hand. Remote control of the cranes, for example from inside the station, is not possible. In addition, the cranes are unable to carry out robotic actions independently. Both cranes were initially mounted at attachment points near the exit lock of the Russian module Pirs and were not intended to operate from other positions on the outer skin of the ISS. To prepare for the replacement of Pirs by the new Nauka research module , an external mission took place on February 16, 2012. With Strela-2, the cosmonauts Oleg Kononenko and Anton Schkaplerow moved Strela-1 to the opposite, largely identical module Poisk . The next outboard operation to move the cranes took place on August 20, 2012 with Gennady Padalka and Yuri Malentschenko . With Strela-1 from Poisk, the two cosmonauts relocated Strela-2 to the new location at the spherical coupling node Sarjas .

Start and installation

The astronaut Jeffrey Williams mounts the newly delivered main arm on the Strela stand (May 22, 2000).

Strela-1 was not delivered into orbit as a finished crane, but transported in individual parts on board two space shuttles and assembled in space . The first components from Strela reached the ISS as part of the space shuttle mission STS-96 on the Integrated Cargo Carrier (ICC) mounted in the payload bay . On May 30, 1999, the stand with control unit and accessories were temporarily attached to the Russian segment during an almost eight-hour outboard operation . The next time a space shuttle ( STS-101 ) visited the Atlantis payload bay, the main boom for Strela was delivered and also temporarily attached to the PMA-1 coupling adapter during assembly work as part of an outboard mission . After the automatic docking of Pirs in September 2001, the already existing components of the Strela-1 were moved to their final place of use near the Pirs hatch during an outboard mission of Expedition 3 on October 8th. However, a test of the function and stability of the crane arm had to be omitted for reasons of time. In an outboard operation on November 12th, the assembly was completed and the first movement tests carried out. Since then, Strela has been operational at Pirs and served as a support to the space travelers on almost every spacecraft mission initiated by Pirs.

Pirs himself carried the components for the Strela-2 with him in the interior at the start. As part of the spacecraft mission of Expedition 4 on January 14, 2002, the base and the crane boom were brought into space through the exit lock and mounted opposite Strela-1 on the outer skin of Pirs. In addition, accessories such as a payload transport container for the Strela system were brought into space and prepared for use.

tasks

The main task of the Strela cranes is to support space travelers during spacecraft missions, especially in the construction and maintenance of the space station. The cranes are mainly used for spacecraft missions from the Russian air locks at Pirs and Poisk. The equipment includes, among other things, a crane arm extension, with which the radius of action can be extended by around 4.6 meters if necessary, as well as a transport container for loading payloads and a work platform foot holder with which the astronauts can attach themselves to the end of the crane boom. With the help of the extension, the crane system is able to reach almost every point on the Russian segment of the ISS.

In addition to the transport of smaller station components and outboard experiments, Strela is used to bring the space travelers themselves to their locations. With several handles mounted on the crane boom, the astronauts can move much faster over the Russian segment during extravehicular missions or can be transported directly to the respective site with the help of the work platform. This saves valuable time during operations, which enables more complex work within the framework of the supply time for the spacesuits .

For example, when the ISS expedition 15 Strela-2 including a crane extension was used to install several meteorite protection shields (Service Module Debris Panels) on the Zvezda module. With the help of Strela, these approximately 2.5 cm thick aluminum plates were removed from the storage frame on the PMA-3 module and transported to the installation site. Even in weightlessness, such tasks can only be carried out by hand to a limited extent.

Components

  • Strela-1 stand with control unit (delivered with STS-96 on May 27, 1999)
  • Astronaut work platform (shipped with STS-96 on May 27, 1999)
  • Strela-1 telescopic boom, 13.7 meters long (delivered with STS-101 on May 19, 2000)
  • Extension arm, 4.6 meters long (shipped with STS-101 on May 19, 2000)
  • Strela-2 stand with control unit (delivered with Pirs on September 14, 2001)
  • Telescopic boom Strela-2, 13.7 meters long (delivered with Pirs on September 14, 2001)
  • Transport container (delivered with Pirs on September 14, 2001)

Web links

Individual evidence

  1. ↑ Ralf Möllenbeck & Sascha Haupt: Expedition 30. Raumfahrer.net, September 4, 2011, accessed on February 20, 2012 .
  2. ↑ Russian ISS Crew Members successfully complete challenging EVA. Spaceflight101.com, August 20, 2012, archived from the original on December 25, 2013 ; Retrieved September 4, 2012 .