Exercise 5.10 Deep Space One (http://nmp.jpl.nasa.gov/ds1/), a spacecraft launched by NASA in October 1998, used AI technology for its diagnosis and control.

For more details, see Muscettola, Nayak, Pell, and Williams [1998] or http://

ic.arc.nasa.gov/projects/remote-agent/ (although these references are not necessary to complete this question).

Figure 5.14 depicts a part of the actual DS1 engine design. To achieve thrust in an engine, fuel and oxidizer must be injected. The whole design is highly redundant to ensure its operation even in the presence of multiple failures (mainly stuck or inoperative valves). Note that whether the valves are black or white, and whether or not they have a bar are irrelevant for this assignment.

Each valve can be okay (or not) and can be open (or not). The aim of this assignment is to axiomatize the domain so that we can do two tasks:

(a) Given an observation of the lack of thrust in an engine and given which valves are open, using consistency-based diagnosis, determine what could be wrong.

(b) Given the goal of having thrust and given the knowledge that some valves are okay, determine which valves should be opened.

For each of these tasks, you must think about what the clauses are in the knowledge base and what is assumable.

The atoms should be of the following forms:

• open V is true if valve V is open. This the atoms should be open v1, open v2, and so on.

• ok V is true if valve V is working properly.

• pressurized V is true if the output of valve V is pressurized with gas. You should assume that pressurized t1 and pressurized t2 are true.

• thrust E is true if engine E has thrust.
• thrust is true if no thrust exists in either engine.
• nothrust is true if there is no thrust.
To make this manageable, only write rules for the input into engine e1. Test your code using AILog on a number of examples.