BY SAMANTHA MASUNAGA
In 1961, an American astronaut reached space for the first time and soared through the heavens in a gumdrop-shaped capsule.
Since then, people have flown to the moon, created space planes and designed rockets that return to Earth for precision landings. But when astronauts lift off next year from U.S. soil for the first time in six years, their vehicle of choice will be another capsule.
Boeing Co. and SpaceX are relying on the tried-and-true design as the two companies each develop spacecraft under NASA contracts to ferry astronauts to the International Space Station.
Despite the sleek spaceships of sci-fi imaginings or the familiar winged body of the shuttle, engineers have returned to the seemingly clunky capsule again and again for a simple reason ? it works.
?The capsule is a very durable technology,? said Matthew Hersch, assistant professor of the history of science at Harvard University. ?It may not be romantic to fly, but it?s going to get you there and back safely.?
Since the end of the shuttle program, the U.S. has relied on Russia to transport its astronauts to and from the space station in the Soyuz spacecraft, another capsule.
Boeing and SpaceX said they are confident their vehicles will fly next year, despite recent reports from the U.S. Government Accountability Office noting that delays for the two companies have pushed the first test flights past the initial deadline.
The new spacecraft have a number of features that weren?t available on earlier capsules ? touch-screen displays, large windows, more powerful electronics and lighter materials.
The spacesuits that astronauts will wear also have been slimmed down. SpaceX has released several photos of its spacesuit, which Chief Executive Elon Musk said was tested to ensure astronauts would stay safe even if the pressure in the capsule dropped suddenly. Boeing?s ?Boeing blue? spacesuit is about 40 percent lighter than previous suits, and the gloves were specially designed to let astronauts interact with touch screens.
In the early days of the U.S. space program, astronauts lamented riding in anything that allowed for such limited human control. Borrowing the name from something you swallow didn?t enhance the appeal.
Initially, there was great enthusiasm for making those spacecraft look like airplanes, but it was difficult to create wings that could navigate various parts of a mission and survive the heat of re-entry, Hersch said.
Any spacecraft rated to carry humans has a specific set of requirements. It must be efficient in its volume with enough space for all necessary life systems, but have as low a mass as possible. It also has to withstand tremendous G-forces, pressure and heat during launch and re-entry.
The heat shield on a capsule?s blunt, slightly curved bottom helps protect the crew as the vehicle re-enters the atmosphere.
Capsules are aerodynamically stable when traveling at supersonic speeds during re-entry and require little maneuvering to return to Earth in an emergency, giving them ?inherent stability,? said David Giger, senior director of Dragon development engineering at SpaceX.
?What?s really interesting about capsule design is it?s aerodynamically efficient both on ascent and descent,? said David Barnhart, director of the USC Space Engineering Research Center. ?It only takes one event to take it back down, which is essentially a re-entry burn, and that?s good because it minimizes moving parts and complexities.?
In creating spacecraft for NASA?s commercial crew program, both Boeing and SpaceX have built on the example of their predecessors.
Boeing constructed its design based on some of the data from the 1950s- and 60s-era Mercury and Gemini, as well as NASA?s Orion, a crew spacecraft that first flew in 2014 and is slated to ride into space atop the agency?s Space Launch System rocket in 2019.
Rob Adkisson, Boeing?s chief engineer for the commercial crew program, said the CST-100 Starliner?s compact capsule design matches its mission as a ?people mover,? compared with the larger space shuttle that essentially functioned as a ?truck back and forth.?
?It looks a lot like Gemini and Mercury,? he said of the Starliner. ?But it?s quite a bit different.?
The Chicago aerospace giant?s Starliner will blast into space on an Atlas V rocket before deploying and docking autonomously at the space station. When returning to Earth, the spacecraft will jettison its service module, deploy parachutes to slow down and drop its heat shield so the vehicle?s air bags can inflate for a softer ground landing.