In building a successor to the space shuttle, NASA has made one component a necessity: a system to let the crew escape should a catastrophe occur on the launch pad or during the first few seconds of flight.

For this reason, a completely new launch escape system is being developed for the Orion crew exploration vehicle, which NASA plans to send into space aboard the Ares rockets in 2015. Both are part of NASA’s Constellation Program to send humans to the moon and, eventually, to Mars.

The new escape system would separate the crew module from the launch rocket in a fraction of a second with a small, controlled explosion. Almost simultaneously, a solid rocket motor would fire, providing a million pounds of thrust to accelerate the module from 0 to 600 miles per hour in 3.5 seconds, pulling the astronauts to a safe distance before the module’s parachutes deploy.

An escape system was judged an unnecessary addition to the space shuttle, which was originally designed to fly frequently, carrying huge payloads such as large satellites into orbit. “There were so many safety elements designed into the shuttle, people thought the safest thing was to just make sure the shuttle could always get back to the runway in case of engine shutdown,” says Jeffrey Hoffman, a former astronaut and currently a professor of aeronautics and astronautics at MIT. “In retrospect, people would agree we need an escape system.”

This point was proved tragically in 1986, when the Space Shuttle Challenger broke apart 73 seconds into flight due to a failure in one of its solid rocket boosters. “If the crew had a launch abort system, there may have been an opportunity for them to escape,” says Henri Fuhrmann, program manager of the new launch abort system at Orbital Sciences, an aerospace company that has partnered with NASA to design and develop the escape system. The space agency has also partnered with Lockheed Martin, Aerojet, and Alliant Techsystems (ATK) on the project.

The design of the new system is based on the launch escape system built for the Apollo capsule; it also has similarities to Russia’s abort system on the Soyuz spacecraft. The Russian system was used successfully in 1983 when a fuel spill caused a fire on the launch pad seconds before liftoff. But NASA’s new system will also feature novel technologies, including a motor for steering the crew module and nozzles to reverse the flow of hot gases. The system is the “first of its kind,” says Kevin Rivers, project manager at NASA’s Langley Research Center, in Hampton, VA. Unlike its predecessors, the system will function at an altitude of up to 91,440 meters during phases of the flight when the rocket is most susceptible to failures.