When NASA astronauts embarked on Servicing Mission 4 to the Hubble Space Telescope in May 2009, they brought with them a variety of specialized tools to perform the servicing operations in a zero-g, vacuum environment.
While the average craftsman may take his hand tools for granted, astronauts work in an environment that limits the types of tools that can be used. Justin Cassidy, the lead systems engineer for Crew Aids and Tools at Goddard noted, "the work astronauts would have to do (is comparable) to opening up a computer and replacing a board while wearing thick gloves on their hands and a fishbowl on their head."
Types of Space Tools
There are three types of tools used by astronauts both inside of the Shuttle and the ISS, as well as outside:
- Crew Aids – hand rails, foot restraints, tether devices. These are generally passive devices that help astronauts maneuver and brace themselves as they work both inside and outside of crew spaces. However, the ISS has a 200-foot network of rail lines with cable-driven controls integrated into the truss’ design to serve as transportation for astronauts and equipment.
- Hand Tools – These manual tools help astronauts perform tasks that are difficult to perform while wearing gloves. Some hand tools include a washer extraction tool, fastener capture plates, and specialized fixturing.
- Power Tools - The primary power tool used by astronauts is a pistol-grip tool, similar to a cordless drill. This version is designed to rotate at about 15 RPM. A specialized mini pistol-grip tool was developed for the Hubble Servicing Mission that had a faster rate, about 210 RPM, to allow astronauts to remove the many screws on the telescope components quickly.
Engineers have also developed specialized tool holders and fixtures that attach to the astronaut's space suits to hold tools and components for specific operations.
Requirements for Space Tool Design
When in space, astronauts live and work in a hostile environment that is different in many ways from working on earth. For example, the lack of gravitational effects while in orbit causes astronauts to modify most of their actions. Much of the equipment in spacecraft is specially designed for zero-g operations, and this design specialization is particularly applicable to tools. Some of the requirements for tools for space operation include:
- A minimal tool weight so as to not impact total vehicle weight
- Cannot cause tears or cuts
- Must be operational in temperatures from -150F to +150F
- Must be operational in a vacuum environment
- Must be operational while wearing pressurized gloves
- Must be able to withstand launch forces and vibrations
Other requirements may be added to individual tools based on specific servicing functions.
Where are Space Tools Designed?
The tools for the Hubble Space Telescope repair missions were developed by the Hubble Space Telescope Extravehicular Activity Team at the Goddard Space Flight Center in Greenbelt, MD. Goddard is the center for the development and testing of tools and devices for all NASA operations.
Engineers at Goddard have a detailed understanding of the requirements of space flight and operation, and spend years designing, building, and testing tools to be used by astronauts. Prototype tools are tested by astronauts in the Neutral Buoyancy Laboratory at NASA’s Johnson Space Center in Houston. The astronauts provide feedback to the Goddard engineers about usability so that the designs can be optimized before the Shuttle ever leaves Earth.
Astronauts rely heavily on the functionality and quality of their tools and devices while operating in space. Engineers provide a significant service in ensuring these tools meet the needs of the astronauts.
Sources
NASA Servicing Mission 4 Essentials
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