Flight Shuttle Databases for CSE 510 Homework assignment

Richard Anderson, Ken Fishkin -- January, 2003

The Assignment

It is January 27, 1986, 5:35 PM (Mountain Time). You are a rocket scientist working at Morton Thiokol. You have just persuaded the others at Thiokol that the launch of the space shuttle "Challenger", scheduled for January 28^th, should be postponed. You believe that the O-rings might fail in such cold weather (estimated 29 degrees at launch).

You have 90 minutes to prepare charts supporting your position before a conference call with NASA starts. Using the data in this handout (also available from the class web site), make your charts.

Fax your answer to 206-633-6504 by 8 AM Monday, 1/13. (Be careful about use of color)

Extra Credit: only use chart-preparation tools available in 1986.

The Database

The databases describe previous shuttle flights ("flights"), and  O-ring damage on them ("damage"), in MS Access format. It's a bit confusing to read, but even this is a significantly cleaner version than what the real Thiokol engineers had to deal with. The values in the databases are also included here, in case you can't read MS Access.

The "flights" table tells you the basic information about each flight:

• ThiokolID - the Thiokol ID assigned to the flight.
• NasaID - the Nasa ID for the flight.
• LaunchDate - the launch date for the flight
• Pressure - the pressure on the joints on liftoff.
• Temperature - the temperature at the joints on liftoff.

So, for example, flight STS-1 launched on 4/12/81, with joint pressure of 50 psi, and a temperature of 66 degrees. Flight STS-2 launched on 11/12/81, with a joint pressure of 50 psi, and a temperature of 70 degrees.

Now, on to the damage. Each flight had two rockets, a Left and a Right. Thiokol assigned an "A" to the left rocket, a "B" to the right rocket, whereas Nasa called them "Left" and "Right". For example, in the table above, the rocket that NASA calls "41-C Left", Thiokol calls "11A"..

Each rocket had three joints: Aft, Center, and Forward. Finally, each joint had 2 rings: Primary and Secondary. This means that each flight had 2*3*2 = 12 O-ring joints.  Some of the database fields are replicated (NasaID , ThiokolID, LaunchDate). The ThiokolIDs now have the "A"/"B" signifiers indicating which rocket they are describing.  The other fields detail the damage to an o-ring joint. Specifically:

• SideID - which side had the damage (left or right)
• JointID - which joint had the damage (Aft, Center, or Forward)
• RingID - which ring had the damage (Primary or Secondary)
• hadErosion - an "X" if erosion damage was observed, "-" if there was none, "?" if no observation was performed. The actual Thiokol engineers had 6 different numbers describing this damage in stupefying detail, this has been collapsed into a simple binary.
• hadBlowby - an "X" if blowby damage was observed, "-" if there was none, "?" if no observation was performed.

Let's look at the same two flights again. STS-1 had no damage in any O-rings. STS-2, however, had erosion damage in the right aft primary o-ring.