Figure 3 ¥ Confined Work Site Range-of-Motion

Motivation
During the First Servicing Mission (SM1), Story Musgrave commented on how the struts at the Solar Array Carrier forward and aft latch work sites constrained his throw while using the Essex wrench.

Procedure

1. Set the ISS Ratchet Wrench in the loosen position with a 7/16" x 3" GFE Socket attached.
2. Place the handle of the wrench between the 15° limit pegs.
3. Turn the bolt 5 turns. The number of turns can be determined from the rod extending perpendicular from the boltÕs body.
4. Place the handle of the wrench between the 30° limit pegs.
5. Turn the bolt 5 turns.
6. Repeat steps #2 - #5 with the Roller Wrench (SSL-RW-17-0200-02) and the 7/16" Socket.

Figure 4 ¥ Maximum EVA Free-Floating Torque

Motivation
The work site around the center Multi-Use Lightweight Equipment Carrier-to-Radiator bolts (which nominally release at 15 ft-lbf) cannot be reached by the Remote Manipulator System, and it is undesirable to set up and take down a Portable Foot Restraint so the task may have to be done free-floating.

Procedure

1. Set the ISS Ratchet Wrench to tighten and place the square drive tang into the torque sensor with the wrench parallel to the handrail and with the handle to the right.
2. Remove boots from foot restraints.
3. While holding the handrail with one hand, apply maximum amount of torque using the wrench in the other hand.
4. Repeat step #3 with the wrench in the loosen position and then in the tighten and loosen position with the handle to the left.

Task Setup
The goal was to rotate a double height 7/16" hex bolt (shown in the middle of Figure 5) connected to a 22:1 planetary gearhead and a 20-1/2" diameter, 1/2" thick copper plate in an attempt to simulate the deployment of the Solar Array-III (SA-III) which has an inertia of approximately 286 slug-ft^2. First the subject was asked to rotate the bolt from 180° (wrench handle parallel to the floor and to the left) to 90° (wrench handle perpendicular to the floor pointing towards the water surface) at approximately 5°/sec and stop the interface at the 90° mark. This simulates the SA-III panel deployment. The task was repeated at a quarter the angular rate or approximately 1.2°/sec to simulate engagement of the SA-III at soft dock. The test subject was asked to comment on their ability to control inertia using both the ISS Ratchet and Roller Wrench.

Figure 5 ¥ High-Inertia, Low Friction Interface Simulation

Motivation
This was done in order to evaluate the need for a ratchet lock-out feature for manual operation of high-inertia interfaces. During SM1 Solar Array-I (SA-I) Primary Deployment Mechanism (PDM) retraction, Tom Akers had limited control of the SA-I, apparently because he was using a ratcheting wrench to drive a high-inertia, low-friction interface. He commented that he would move the wrench 10° and the interface would move an additional 30° before friction caused it to stop. In the event that there is a manual PDM retraction on the Third Servicing Mission, an evaluation must be done to determine if a tool should be available that does not ratchet thereby giving the crew member positive control of the array in both directions. Some involved with the development of Solar Array-II think that a non-ratcheting tool is the safest way of handling the PDM.

Procedure

1. Set the ISS Ratchet Wrench in the tighten position with a socket attached and with the handle parallel with the floor and to the left (180° position).
2. Turn the bolt clockwise at 5°/sec. The rate can be determined using the movement of the rod extending perpendicular from the boltÕs body against the dial attached behind the bolt.
3. Attempt to stop the bolt at the 90° mark.
4. Repeat steps #1 - #3 turning the bolt at 1/4 the rate specified in step #2 (approximately 1.2°/sec).
5. Repeat steps #1 - #4 with the Roller Wrench (SSL-RW-17-0200-03).

Task Setup
There were two objectives of the task: determine the ability of a weightless suited subject to apply 60 ft-lbf of torque required to sheer the Aft Shroud Door Latches (ASDL) using the ISS Ratchet attached to a cheater bar; and evaluate the impact of a ratchet wrench on the useful throw by measuring the throw envelope while simulating shearing of the ASDL bolts. The torque sensor simulated the ±V2 Scientific Instrument ASDL bolts. It was centered 0.74" parallel from the surface of the plate to mimic the ASDL bolt's distance from the door surface and the female end of the sensor was 16.5" to the right of the vertical handrail (simulating the location of HR16 on the +V2 side and HR7 on the -V2 side) as shown in Figure 6. Torque data was sent to the surface from the sensor through a cable and recorded on a computer. The useful throw envelope was measured with a tape measure and recorded.

Figure 6 ¥ Aft Shroud Door Latch Work Site Simulation

Motivation
Because of the pitch of the teeth on the ratchet wrench and because it is attached to the cheater bar, the useful throw of the wrench may be severely limited and the handle of the wrench may even move outside of the EVA work envelope before the wrench locks. Because of the roller wrench's almost instantaneous locking, the useful throw can be increased. There may also be a need for the roller wrenchÕs smaller throw over that of the ratchet wrench for EVA applications that require multiple throws of a long-handled manual tool. For instance, the large range of motion needed to drive or fail the ASDL bolts using a long handle may be especially fatiguing in a suit.

Procedure

1. Remove the palm wheel from the ISS Ratchet.
2. Attach the wrench to the ISS Cheater Bar.
3. Set the wrench to loosen and place the square drive tang into the torque sensor.
4. Pull the wrench toward you until the wrench locks.
5. The perpendicular distance from the edge of the task board to the end of the wrench handle will be measured and recorded.
6. Apply the maximum amount of torque using the wrench.