The Hubble Space Telescope Second Servicing Mission (SM-2)

CREW AIDS AND TOOLS

The Hubble Space Telescope (HST) was designed and built with a number of handholds and other accessories to help spacewalking astronauts service the observatory. The crew members of Space Shuttle Mission STS-82 will take more than 150 other crew aids and tools with them when they blast off on their planned 10-day servicing mission in early 1997.

These crew aids and tools, known as Space Support Equipment (SSE) hardware, range from a simple bag for carrying some of the smaller tools to sophisticated, battery-operated power tools. This hardware will be used by Shuttle crew members who will make at least four spacewalks to carry out the challenging task of servicing the spacecraft.

During this second scheduled servicing mission for the Hubble Space Telescope (HST), a crew of seven astronauts will rendezvous with HST, grapple the telescope with the shuttle remote manipulator arm and dock it in the Shuttle bay on the HST Flight Support System (FSS). Over the next seven to eight days, four of the astronauts, working in teams of two, will use the crew aids and tools to replace two of the original scientific instruments, the Goddard High Resolution Spectrograph (GHRS) and the Faint Object Spectrograph (FOS), with two new state-of-the-art instruments, the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

The crew also will replace one of the Fine Guidance Sensors (FGS) with an upgraded spare. Two of the three on board tape recorders will be replaced, one with a spare back-up and the other with a new state-of-the-art, high performance Solid State Recorder (SSR). Several electronic units also will be changed out.

Crew Aids: These are fixed-in-place or portable equipment items, other than hand tools, used to assist crew members in accomplishing servicing mission tasks. Crew aids permit the astronauts to maneuver safely or to anchor themselves in one location while working in the weightlessness of space. They also help in moving Orbital Replacement Units (ORUs) and Scientific Instruments (SIs), protect equipment and crew during the changeout activities, and provide temporary stowage of equipment during Extra Vehicular Activities (EVAs). Examples of crew aids are: handrails, handholds, transfer equipment, protective covers, tethering devices, grapple fixtures, foot restraint sockets, and stowage and parking fixtures.

Tools: These hand-operated devices allow EVA astronauts to more efficiently perform intricate, labor-intensive tasks. Tools allow the crew to access equipment bays on both the spacecraft and the Shuttle; and to remove and install ORUs and SIs; to restrain crew members, tools and hardware through the use of platforms, caddies and equipment tethers. Tools also provide for temporary storage of hardware items such as nuts, bolts, fittings, and lighting, and manual operation of spacecraft and payload mechanisms during the EVAs.

Among the tools to be carried aboard STS-82 for HST servicing are, the Power Ratchet Tool , the Multisetting Torque Limiter, adjustable extensions with 7/16-inch sockets, a newly developed, battery powered Pistol Grip Tool, and a series of new connector tools. Spares of all the tools will be carried on the Shuttle to ensure the success of the mission and safety of the crew.

Power Ratchet Tool (PRT): The power ratchet tool is powered by a 28-volt battery. Made of titanium and aluminum, the 17-inch (43 cm) tool will be used for tasks requiring controlled torque, speed or turns, and can be used where right-angle access is required.

Multisetting Torque Limiter (MTL): This tool is provided to prevent damage to hardware due to the application of torque which may exceed design limits. Multisetting torque limiters are used in conjunction with the power tools or hand tools that interface with bolts and latches on the telescope.

Adjustable Extensions: Two extensions were designed to be adjustable, allowing astronauts to move more easily and efficiently.

Pistol Grip Tool (PGT): This unique tool was designed for use by the astronauts during EVA activities. The experiences of crew members on HST's first servicing mission led to recommendations for this smaller, more efficient tool for precision work in a space environment. The PGT is a self-contained, micro-processor controlled, battery-powered, hand-held tool. It also can be used as a non-powered ratchet wrench. The PGT's micro processor can be programmed to control limits for torque, speed, number of turns and angle.

The crew aids and tools are developed by both Johnson Space Center in Houston, Texas and Goddard Space Flight Center in Greenbelt, Md.

For additional information contact:

Tammy Jones

Goddard Space Flight Center

Office of Public Affairs

(301) 286-5566

Internet: http://www.gsfc.nasa.gov

Space Telescope Science Institute

Office of Public Outreach

(410) 338-4707

Internet: http://www.stsci.edu