NASA announced plans this week for a new launch vehicle as part of its manned space program. If built, it would be the largest rocket ever flown, capable of carrying payloads of up to 286,000 pounds. The proposed program, simply titled the Space Launch System (SLS), is planned to undergo its first launch in 2017. This program will potentially mark the first time the United States will engage in this type of manned launch since the end of the 1970s.
"The idea behind the SLS is that it can get us beyond low earth orbit," said Roger Launius, senior curator at the Smithsonian Air and Space Division of Space History, and former Chief Historian at NASA, in an interview with The News-Letter. "All we've done [for the past forty years] is fly around in circles over our heads."
The Saturn class rockets of the 1960s and 70s were replaced by the space shuttle as America's means of human spaceflight. The fleet of five shuttles flew 135 missions over thirty years, ending just two months ago with the landing of Atlantis in July. The shuttle program was envisioned as a cost-effective program wherein man could be brought up to an orbiting space station and later returned by the same spacecraft. Over time, it became clear that the cost-saving aspects were not effective. Also, a major restriction of the shuttle program was that it limited man to near-Earth missions.
In 2010, in a speech at the Kennedy Space Center, President Obama outlined his plan for the United States' renewed effort in space. The new program would be built around a heavy lift vehicle, now envisioned as the SLS, for the purpose of entering deep space (deep space is the region beyond the gravitational field of the Earth). The first proposed destination is to an asteroid, planned for around 2025. Then, "by the mid-2030s, I believe we can send humans to orbit Mars and return them safely to Earth. And a landing on Mars will follow. And I expect to be around to see it," said Obama in his 2010 speech.
Dr. Launius has a different view of the project. Public perception currently holds that the nation gave unqualified support to the Apollo program in the 1960s. However, "at the time of the moon landings in 1969, everybody was excited for it," said Dr. Launius, "but the reality is that the rest of the time they viewed it less as something that they thought was cool." With respect to Mr. Obama's speech, Dr. Launius sees it as primarily budgetary in nature, similar to other presidential speeches such as one by George Bush in 2004. According to Dr. Launius, "It's impossible politically to predict anything more than ten years out. We're going to spend the next decade flying to the International Space Station and that's all."
The SLS does have a number of key features to its benefit. Early versions of the system will employ currently used components, such as rocket engines and boosters, to speed up testing and begin with reliable hardware. Later on, these will be replaced with newer and better versions as technology improves. One example of this is the Pratt and Whitney Rocketdyne J-2X engine, an updated version of the Saturn V second stage engine.
The SLS is also being built to accommodate many possible variations. "You need a different type of vehicle if you're going to go to the moon rather than going to Mars," said Dr. Launius. One version will be for manned missions, and will be joined with the Orion Multi-Purpose Crew Vehicle, currently under development as well. This capsule, reminiscent of Apollo-era capsules, is designed for deep space missions up to six months in duration. Another variant will be for cargo, and include a large cargo bay instead of a crew capsule.
Dr. Launius sees organized spaceflight as a pyramid, with the pinnacle being successful human spaceflight. With the end of the shuttle program, "we've just fallen out of the top of the pyramid. Will we get back into it anytime soon, is in my mind, the interesting question." Achieving human space flight beyond the influence of Earth's orbit would create a new cap for the pyramid. "I'd be surprised if I saw a human back on the moon before the end of my life, [though] all that could change if we had a good reason to go."
