Why Retire the Space Shuttle Programs?

For this post, I want to discuss the reasons the government decided to retire the Space Shuttle programs.  From the information I was able to gather, it seems that two large factors leading to the retirement of the Space Shuttles involved economic and technological disadvantages.  The two historical failures of the Space Shuttles (the Challenger and the Columbia tragedies) did not help the help the case of keeping them around either.

The Challenger

28 Jan 1986, the Space Shuttle Challenger exploded 73 seconds after lift-off, resulting in the deaths of 7 crew members.  The cause of this failure was the malfunction of an O-ring in the right solid rocket booster of the shuttle.  This resulted in a breach in the solid rocket booster joint it sealed, which allowed pressurized hot gas from within the solid rocket motor to reach the outside and impinge upon the adjacent solid rocket booster attachment hardware and external fuel tank. This led to the separation of the right-hand solid rocket booster’s aft attachment.  In summary, all this led to the structural failure of the external tank.

The Columbia

01 Feb 2003, the Space Shuttle Columbia disintegrated shortly before it was scheduled to complete its 28th mission, killing the seven astronauts who made up its crew.  The failure of the Columbia was a result of damage sustained during launch.  A piece of foam insulation the size of a small briefcase broke off from the Space Shuttle external tank under the aerodynamic forces of launch. The debris struck the leading edge of the left wing, damaging the Shuttle’s thermal protection system and leaving it vulnerable to the intense heat generated from atmospheric friction.

Economic Disadvantages

Though the initial goal for the Space Shuttle programs was to provide access to space as a routine and inexpensive activity, access to space remained (and still remains) a highly expensive and highly inflexible activity.  The price to launch a payload aboard the Space Shuttle is still $10,000 per pound, a figure that has not gone down in over a decade.  It is the versatility of the Space Shuttles and their ability to perform multiple roles that made them so expensive.

Technological Disadvantages

NASA has always regarded crew safety as its number 1 priority; however, a long-standing drawback to the Space Shuttles was the crew escape system.  The requirements for the 2nd generation Reusable Launch Vehicle were a 1 in 1000 Loss of Vehicle and a 1 in 10000 Loss of Crew over the entire flight profile, which implied a 90 percent confidence in the Crew Escape system.  Unfortunately, the technology of the Space Shuttles only generated a 75 to 80 percent confidence in the system according to the data of the Naval Aviation Center.  The Crew Escape system only operated when the shuttle is in a controlled gliding flight after reentry and is unable to reach a runway.  It was thought to be pointless to pursue further advancements in an aging technology when the cost of these begins approaching the cost of developing a replacement for the whole system.


The J-2X Engine

I thought this week I ought to describe to you the new engine which will be used for human travel in space.  The J-2X engine is a variation of the J-2T engine, which was a variation of the J-2S engine.  NASA began construction of the engine in 2007 at the Stennis Space Center.  Nine test of the heritage J-2 engine components were conducted in preparation for the design of the J-2X engine.  The J-2X was chosen for the Project Constellation manned lunar landing program.  Though the project was cancelled by the President, development of the J-2X has continued for its potential as the second stage engine for the heavy-lift Space Launch System.

What Now?

Now that the space shuttle programs have been terminated, what is there left for NASA to do?  With no more space shuttles, will we no longer be able to explore space?  Was space travel not the main mission of NASA?  According to the NASA website, the ending of the shuttle programs is not at all necessarily a bad thing.  It is not the end of NASA or even human space travel.  “NASA has a robust program of exploration, technology development and scientific research that will last for years to come,” (What’s Next For NASA?).

So what really is next for NASA?  NASA is going to be continuing work in the following areas:

  • exploration- NASA is working on developing a new flight vehicle (Space Launch System rocket) to transport humans beyond the orbit of Earth.  Engineers are also working to construct other technologies necessary for human exploration, such as solar electric propulsion, refueling depots in orbit, radiation protection, and high-reliability life support systems.
  • International Space Station- It is the centerpiece of human flight in low Earth orbit.  The International Space Station acts as an experimental station for exploration technologies and as a national laboratory, where crew members have committed to scientific research.
  • aeronautics- NASA is researching methods of constructing aircraft which is safer, more efficient, quieter, and environmentally responsible.  They are working to create traffic management systems that are safer, more efficient, and more flexible.  Technology is being developed to improve routing during flights and to give aircraft the ability to climb to and descend from their cruising altitudes with ease.  NASA promises to continue to validate new, complex aircraft and air traffic control systems to ensure they meet extremely high safety levels.
  • science- NASA is conducting missions that will seek new knowledge and understanding of Earth, the solar system, and the universe.  NASA’s science vision encompasses questions that are all practical, enticing, and profound.

A History of the Space Shuttle Programs

I think it is important for us to establish a little background to the NASA space shuttle programs before beginning a discussion about their termination.  I will present the shuttle missions chronologically by year and provide mission summaries for some of the missions I believe to be most important.  I suggest reading the information provided by the links to understand the other missions that I don’t describe.  This post is going to be a little lengthy, but bear with me because after reading this we will be a little more educated.

Space shuttle launches began in 1981 and were recently ended this year.  That is 30 years of successful travel in space via space shuttles.