Challenger: A True Story of Heroism and Disaster on the Edge of Space

O-rings were large pieces (12 feet in diameter) of circular rubber that were needed to seal the joints of rocket boosters. Due to their enormous size, the rocket boosters could not be assembled at the plant where they were manufactured and were instead shipped in pieces to Cape Canaveral and assembled there. The presence of the O-rings ensured that each separate section of the rocket booster was airtight, preventing dangerous fuel from leaking out. Their rubber composition made the O-rings malleable so that they could accommodate fluctuations in temperature that occurred as the rockets fired, shifting into place to secure the seal. When its rubber became too cold, however, the O-rings lost their elasticity, becoming brittle and rigid and unable to shift into place to seal the joint as intended. It was the failure of the O-rings to seal during cold temperatures that caused the Challenger disaster.

The solid rocket boosters discussed in this book were 149 feet in height and filled with a dangerous mix of chemicals. They were needed to provide the thrust that propelled shuttles out of Earth’s orbit and against gravity during the first two minutes of flight. The boosters, unlike the other components of a shuttle, could not be controlled once lit. The enormous size of the boosters prevented them from being designed as a single piece; instead, they consisted of sections that fit together. Securing these sections tightly together was the job of the O-ring.

The space shuttle was a reusable spacecraft and was first envisioned in the 1970s. Prior to this, a spacecraft was designed to shed many of its components as waste at various junctures of the mission, leaving them behind when they were no longer needed to become space or moon debris or crash into the ocean. A reusable craft, however, would be cost effective, making regular trips into space a reality.

The shuttle contained three main components: the solid rocket boosters, the external fuel tank, and the orbiter. The orbiter was the compartment that carried the crew and cargo and traveled into space. The fuel tank not only contained the mixture of hydrogen and oxygen that propelled the engines that drove the orbiter into flight but also acted as a structural support as the orbiter rode on its back during launch. The solid rocket boosters were the element that provided the thrust to launch the shuttle beyond gravity.