1. “Return from Salyut” “Rental Car”
Tutorial 6: Case Study
“Return from Salyut”
“Rental Car”
SY DE 142 – June 28, 2004
Introduction to Human Systems Engineering
Waterloo, Ontario, Canada

2. Outline Case 1: “Return from Salyut” Question and Discussion on Case 1
Case 2: “Rental Car”
Questions and Discussion on Case 2

3. Case Study #1 Return from Salyut
Time: June 3, 1971
Place: Suyoz 11 spacecraft
Synopsis: Firing of the explosive bolts -connecting the command module with the orbital module - opened the pressure evaluation valve.
Result: All three cosmonauts were dead.

4. Return from Salyut Questions
1. Break down the valve closing situation in terms of Human Action Cycle.
2. Why were the cosmonauts unable to close the valve?
3. Why didn't the cosmonauts in the Salyut capsule have suits?

5. Return from Salyut HAC
Goal: Restore oxygen to the capsule. (or “Stop oxygen leak”)
Intention: Close the valve.
Sequence of Actions: Turn the valve.
Execution of Actions: Physically turning the valve
World: Valve turns and each turn closes it further.
Perceive state of the world: Visual change in valve control, feel of valve turning
Interpret: Valve has turned and is closing
Evaluate: Has valve turned enough to stop oxygen leak? No. Goal not achieved.

6. Return from Salyut Solutions
2. Why were the cosmonauts unable to close the valve?
It required more turns than were physically possible to execute under conditions of lost oxygen. The designers of the valve had not taken into consideration its conditions of use.

7. 3. Why didn't the cosmonauts in the Salyut capsule have suits?
The capsule was being used for three cosmonauts instead of the two it was designed for. This is an example of a system being used outside of its design parameters.

8. Rental Car Overview Time: Middle of World War II
Place: US Army Air Base, Small Pacific Island
Synopsis: Redesign of P-47 Thunderbolt fighter plane was about to cost a pilot’s life in the middle of an attack from the Japanese airfighters

9. Rental Car Questions
Use “Action Cycle” analysis to describe the situation that occurred in this case.
Identify the Gulf of Execution in this case. What does this suggest for design?

10. Rental Car Solutions
Goal: survive the Japanese attack and protect the planes
Intention: flying a P-47 Thunderbolt
Sequence of actions: run to the ready-room, find a free plane, identify controls, use controls to fly the plane
Actions: physical actions of running, finding, identifying, eluding (could not find controls to fly the plane)

11. Rental Car cont….. Solutions
World: the plane was raced up, down, across, and around the airstrip on the island, bombs dropping
Perception state of the world: physically seeing and sensing the plane moving relative to the bombs dropping
Interpreting the perception: Plane did not fly, but the bombs did not hit the plane
Evaluation of interpretation: the goal was achieved even though the plane did not take off.

12. Rental Car Gulf of Execution
Occurs between intention and action
Example: intending to fly the plane (intention) and not finding the controls that will allow you to do that (action)
Suggests poor control/display design, lack of consistency with prior designs, not intuitive, no consideration that use will be under circumstances where there may not be time to train the pilots on the new design.