Aerospace Engineering Essay Example

Introduction

On 28th of January 1986, a team of 11 astronauts aboard the space shuttle Challenger perished in what would become one of the most infamous aerospace engineering failures. The Challenger which was on its 10th mission to space. Among the crew members was Christa McAuliffe, a 37-year-old high school teacher who had earned her spot through the Teacher in Space NASA program. McAuliffe had undergone some few months of training and was set to become the first ordinary American citizen to go into space. The space shuttle launch had been postponed for six days due to unfavorable weather conditions, technical problems as well as schedule changes. On 11:39 a.m., Challenger lifted off from Kennedy Space Centre at Cape Canaveral, Florida. 73 seconds later the space shuttle exploded in the air to the disbelief of thousands of onlookers on the ground and all over the world (History.com Editors, 2010). It would later be established that the accident was due to some technical and ethical issues on the Challenger and the Space Shuttle program.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

Technical Problems

After the disaster, President Ronald Reagan ordered a commission of inquiry, headed by William Rogers, to look into the Challenger disaster to determine the causes and to recommend future corrective measures. The commission was able to conclude that the accident was due to a failure in the rubber O-Seal that separated the sections of the rocket boosters. According to The Engineer (2006), the testing of the seals had never been done at such cold temperatures. The temperatures in the morning of the challenger space launch were freezing. The rubber seals had the functions of connecting the different sections of the rocket boosters, as well as prevent the fire from the solid rocket boosters from leaking out of their compartment.

A typical space shuttle is made up of three sections. There is the Orbiter which acts as the housing compartment for the crew as well as the luggage. The Orbiter has three Space Shuttle Main Engines(SSME) that contribute to providing lift during takeoff. There is the External tank which has storage as well as structural functions. The External Tank has liquid hydrogen fuel as well as liquid oxygen oxidizer. The External Tank supplies the oxygen to the Orbiter's engines under pressure. It also serves as the structural support for attachment of the Orbiter and the Solid Rocket Boosters(SRB). The External Tank is the only part of the shuttle that is non-reusable. The SRBs are the two cylinders beside the External Tank. The SRBs contain solid fuel instead of the liquid fuel as in the External Tank. They are responsible for generating 80% of the thrust needed during liftoff. They fire for about 2 minutes after takeoff before their fuel is exhausted. They detach from the External Tank and fall back to the ground where the recovery crew collects them.

The SRBs had to be made in four-section segments to enable their transportation from the facility of Morton-Thiokol, the company that held the contract to manufacture NASA's SRBs, to the Kennedy Space Center in Utah. The sections are then transported to the Space Centre on railroads. On arrival, NASA assembles the SRBs by stacking not welding. The joints created by the assembly at Kennedy Space Centre are called field joints. That is where the problem occurred in the Challenger (Mark Rossow, 2012). Fuel combustions from one of the SRBs leaked through one of the field joints and weakened or burned a hole through the External Tank, hence igniting the contents of the External Tank (Mark Rossow, 2012).

The upper segment of a Solid Rocket Motor(SRM) is connected to the lower section using a pin that passes through the tongue of the upper portion and a U-shaped receptacle on the lower segment. The engineers attach 177 of such pins around the circumference of each joint. The joint must be sealed at the time when the fuel is burning and generating a high quantity of hot gasses under high pressure. Two O-rings accomplish the sealing. There is the primary O-ring and the secondary O-ring. The SRM O-rings were made from a rubber-like synthetic material called Viton (Mark Rossow, 2012). Zinc chromate putty is applied on the joint during assembly to prevent the fuel from coming in contact with the rubber. Such contact will cause the rubber to degrade.

The Ethical Issue

One of the ethical issues is that NASA knowingly took extra risk in a bid to gain congressional approval and avoid further budget cuts. NASA had planned a record 24 flights in 1986. The records indicate that the Challengers launch date had already been pushed back several times. The management was desperate to gain public approval and was pushing for the launch of Challenger. A day before the launch, some of Thiokol's engineers launched concerns over the weather and cold conditions, but these concerns didn't appear serious to the management.

The second ethical question raised was that Thiokol was under pressure to deliver SRMs to NASA after hearing about NASA's intention to source for a second supplier of Solid Rocket Motors. Congress desired to ensure a steady supply of motors for the shuttles military payloads. According to the commission's report, the possibility of a second supplier was a cause of alarm for Thiokol. The management chose to reverse their position and ignore the recommendations of their engineers to accommodate a significant customer who was NASA.

The third ethical issue is that NASA failed to meet the second requirement of informed consent. The space program was an experiment, and if someone is taking part in a trial, the researchers have to obtain informed consent from the individual. There are two rules for informed consent. The first rule is that the person taking part in the experiment should agree to take part in the test without coercion. The second rule is that the participant should have all the information needed for the research in an understandable form that will allow them to make a reasonable decision of whether they want to be part of the experiment or not. In NASA's case, the shuttle crew was the experiment's participants, but those in charge didn't inform the crew about the teleconferencing that happened the evening before the launch where Thiokol's Engineers raised concerns over the temperature. They were only told of the ice on the launch pad.

Recommendations

Certain precautions could be enforced to ensure the safety of the crew and the success of a mission. The images of the launch indicate black smoke that was emanating from the left SRM. Whether the NASA team spotted the smoke before or after the lift is not definite. However, the organization needs to increase the time span between ignition and lift to allow the technical team to spot any defects in the shuttle's functions. They also need to provide a means to cancel the launch before lift if the engineers detect a flaw.

The inquiry commissions results indicate that the technical team had raised some concerns over the weather. That means that the launch had some unaddressed concerns that would prove to be fatal. The shuttles are designed to be launched year round regardless of temperature, but just like planes, some weather systems favor take-off and landing and where human lives are involved, it is preferable to avoid all risks. The Engineer (2006), indicates that the launch had been postponed several times before due to poor weather. It, therefore, makes sense to delay the mission at least one more time for the same reason to keep the crew safe.

NASA along with Thiokol need to redesign the SRMs to increase their functionality in cold weather. Even if the management had postponed the launch and waited for warm weather, the disaster would have happened later because of the flaw that exists in the SRBs design. It was purely due to luck that the accident had been averted in earlier missions because earlier models had been using the same designs. The engineering team needs to find a way of making the field joints more resilient. The rubber joints have to be able to withstand extreme temperatures.

References

History.com Editors. (2010, February 15). Challenger Explosion. Retrieved from HISTORY: https://www.history.com/topics/1980s/challenger-disaster

Mark Rossow. (2012). Engineering Ethics Case Study: The Challenger Disaster. New York: Mark P. Rossow. Retrieved from https://thegrcbluebook.com/wp-content/uploads/2013/01/Ethics-Challenger-Disaster.pdf

The Engineer. (2006, October 24). The Space Shuttle Challenger Disaster. Retrieved from engineering.com: https://www.engineering.com/Blogs/tabid/3207/ArticleID/170/The-Space-Shuttle-Challenger-Disaster.aspx