Friday, December 9, 2016
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Privatizing Outer Space

Hawthorne, CA — When NASA retired the last of its Space Shuttles in 2011, the organization announced that it would no longer be in the business of building and launching low-orbit vehicles. At the time, it looked as though the U.S.A. was abdicating its role as a leader in space travel research. American astronauts and resupply missions to the International Space Station (ISS) have had to rely on Russian Soyuz rockets, a solution that does not sit well with many Americans.

The Soyuz design dates back to the 1960s, and is understandably regarded with suspicion by American astronauts who are assigned to use it to get to the ISS. But the Soviets in their heyday built a number of these craft, and one Soyuz is permanently moored to the ISS to be used as an escape craft in an emergency. In the wake of the Shuttle Program retirement, American business and ingenuity have rescued our space program from what had looked like an impending nosedive. Private enterprise has come to the rescue in the form of SpaceX — a privately-held company based in California. The U.S. government is still involved to some degree, providing shared launch and support facilities at Cape Canaveral, Florida, as well as at California's Vandenberg Air Force Base.

NASA has awarded a hefty contract to SpaceX to carry out ISS resupply, which have so far been successfully performed by unmanned missions. This is a whole lot less costly than designing, building and maintaining a new fleet of low-orbit shuttles by NASA. Unlike other supply efforts, the company's Dragon module not only carries a significant payload, it is able to return to Earth with a cargo, using drogue parachutes and splashing down in the Pacific Ocean. Unlike some of the early U.S. space missions, SpaceX is able land with almost pinpoint accuracy, making it easy to zero in on the floating Dragon module very quickly for retrieval, using fairly small boats, not a fleet of naval search vessels and aircraft carriers.

Built from the Ground Up
SpaceX developed Dragon from a blank sheet to its first mission in just over four years. It is the first privately developed spacecraft to attach to the International Space Station (ISS). In May 2012, Dragon became the first commercial spacecraft to deliver cargo to the ISS and return safely to Earth, a feat previously achieved only by government spacecraft. In October 2012, Dragon completed its second mission to the ISS, its first of 12 official cargo resupply missions for NASA. Its most recent mission, completed as this issue went to press, ran into some technical difficulties with the propulsion system. Yet SpaceX engineers were able to make corrections from their mission control center, and the Dragon docked successfully, delivering its cargo, which included some fresh fruit, then reloaded with freight to be returned to Earth {?} a first for unmanned supply vehicles.

Payload Capability
Dragon carries cargo in a pressurized capsule and an unpressurized trunk. It can carry 3,310 kilograms (7,297 pounds), split between pressurized cargo inside the capsule and unpressurized cargo in the trunk, which also houses its solar panels.

The Dragon spacecraft has been built to carry both cargo and astronauts. Under a $440 million agreement with NASA, SpaceX is developing refinements for transporting crew, including seating for seven astronauts. The company expects to make its first flight with crew by 2015.

Advanced Heat Shield
According to the company, Dragon has the most effective heat shield in the world. Designed with NASA and fabricated by SpaceX, it is made of PICA-X, a high-performance variant on NASA's original phenolic impregnated carbon ablator (PICA). PICA-X is designed to withstand heat rates from a lunar return mission, which far exceed the requirements for a low-Earth orbit mission.

Smooth, Controlled Reentry
Dragon's passively stable shape generates lift as it reenters the Earth's atmosphere. Its 18 Draco thrusters provide roll control during reentry to keep it precisely on course toward the landing site before its parachutes deploy.

In the meantime, there have been retirement parties all over the U.S., as the last four Space Shuttles have been retired to museums. The Enterprise is on display on board the Intrepid Sea-Air-Space Museum in New York, NY. The Discovery is ensconced in the Smithsonian Institution's National Air and Space Museum in Chantilly, VA. The Atlantis is fittingly exhibited at the Kennedy Space Center, Merritt Island, FL. And the last retiree, the Endeavour, has come to rest at the California Science Center, Los Angeles, CA.

Why has this private space venture worked so well? For one thing, SpaceX has been able to draw on much of the technology developed by NASA over the years — learning from past mistakes, and going directly to new, advanced spacecraft designs. In addition, there is a long-standing culture among American aerospace companies of building spacecraft parts and systems on contract from NASA, so they already know how to do it. It's free enterprise at its best, coupled with a lot of American experience and know-how.

Web:
http://www.spacex-com

 
 
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