The Challenger O-Ring Analysis: Week 5

For this week’s data analysis, I used publicly available data from the Challenger Space Shuttle O-ring disaster. The model developed in Python involved determining the number of O-rings that would disintegrate at 31 Farenheight (-0.555 Celsius). The Challenger Space Shuttle incident of 1986 was later connected to the failure of the rocket’s O-rings (integral for lift-off) which disintegrated as a result of low temperatures.

I was interested in observing whether there was a correlation between temperature and pressure and if in fact, low temperatures directly impact O-ring disintegration. Data used for this analysis was obtained from the UCI Machine Learning Repository and converted into an excel file. The data included the total number of O-rings (6), the number of rings experiencing thermal distress, launch temperature and leak-check pressure. The excel file loaded onto a data frame and the data was printed out into a table:

Number of O-rings Distress Temperature (F) Pressure (psi)
6 0 66 50
6 1 70 50
6 0 69 50
6 0 68 50
6 0 67 50
6 0 72 50
6 0 73 100
6 0 70 100
6 1 57 200
6 1 63 200
6 1 70 200
6 0 78 200
6 0 67 200
6 2 53 200
6 0 67 200
6 0 75 200
6 0 70 200
6 0 81 200
6 0 76 200
6 0 79 200
6 2 75 200
6 0 76 200
6 1 58 200

To study the correlation between pressure and temperature, a regression analysis was completed, with the independent variables (Temperature and Pressure) and the dependent variable (Distress O-rings). These variables represented the crux of the regression model.

week5

The model used for this analysis, ordinary least squares regression, estimates the unknown parameter in a linear regression model (assuming that there is a linear relationship). The model.summary() provided an R-square value of 0.354, which indicates that the data does not fit a linear relationship. With this model we can determine the number of O-rings that would disintegrate under a specific temperature (31F) and pressure conditions (0,50,100,200 psi):

week5(2)

From this analysis, we can conclude that O-rings can disintegrate (~2) at 31F, at any change in pressure (0-200), further indicating the importance of monitoring temperature and ensuring that take-off does not occur at freezing temperatures. It’s important to note that not all data sets will depict a linear relationship, but identifying the relevant variables will assist in identifying the type of analysis needed.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s