NASA Future
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The monster rocketAll of NASA's Mars plans revolve around a core technological need: a big rocket capable of getting large, heavy payloads off the Earth. The Saturn V rocket that carried humans and hardware to the moon could lift 120 metric tons to low-Earth orbit. By comparison, the most powerful launch vehicle operating today is the Delta IV Heavy, which can do about 29 tons. The space shuttle could loft 25. NASA's Space Launch System, or SLS, is scheduled to debut in either 2017 or 2018. It will initially be capable of lifting 70 tons to low-Earth orbit. A future, upgraded version will do 130. The International Space Station, the largest human-made object in space, weighs about 420 tons. It took more than a decade of shuttle flights and Russian rockets to assemble. Just four SLS flights could do the job, assuming the station could be redesigned to fit inside the rocket's payload fairing. The space shuttle's payload bay was less than five meters wide. The final SLS variant will have a mammoth 10-meter fairing. SLS Program Manager Todd May calls the 10-meter variant "every rocket builder's dream." During an interview at NASA Marshall, May said SLS is a critical component of NASA's Mars plans. "Just imagine taking a trip out to the desert," he said. "You're not coming back for three years. Do you want to take the Volkswagen, or do you want to take the biggest SUV you can think of?" With a smile, he added, "Or an RV. Or several trains." Despite the Space Launch System's impressive capabilities, it has been a recurring target of criticism since its announcement in 2011. For starters, there's the price tag. In August, it was announced that SLS development would cost $7 billion from 2014 through the rocket's first launch. To arrive at that cost and schedule, NASA used a statistical model called a Joint Confidence Level (JCL) assessment, which is normally used for science missions. One benefit of the JCL, said May, is that program managers can give top NASA brass hard data on how realistic a project's timeline is, given current funding levels. In the case of SLS, the JCL reported a December 2017 debut might not be feasible, which led to a predictably heated is-it-a-slip-or-not press conference. May, who still plans to launch in 2017, is tasked with keep his team's morale high, all while providing honest estimates to the public. “We’re trying to do the right thing,” he said. "We’re trying to be transparent.” After SLS and Orion are flying, their development costs should decrease, freeing up money for other Mars hardware, like crew habitats. But another critique of SLS is the rocket's anticipated low launch rate, which could drive up operational costs. Nick Cummings, the integration manager of Ground Systems Development and Operations at Kennedy Space Center, said this concern is unfounded. "We're planning for a launch rate of about once per year," said Cummings. "That once every few years [rate] is somehow the talking point that just never dies." Cummings' statement was echoed by Gerstenmaier, who said once-a-year launches will begin after the first crewed Orion flight in 2021. "By the time we're at EM-2 [Exploration Mission 2], we're set up with a capsule that can go do things routinely," he said. "We're set up with SLS, which can get us there, and we're set up with the basic underpinnings that can let us go into deep space." Besides humans-to-Mars gear, what else will NASA launch with SLS? One possibility is the Europa Clipper, a mission to understand the subsurface ocean of Jupiter's icy moon. SLS could slash four years of travel time from the mission, according to Boeing, the rocket's prime contractor. A shorter travel phase would reduce the mission's operational costs. Bill Hill, NASA's assistant deputy associate administrator for Exploration Systems Development, said planetary scientists prefer the heavy-lift rocket for Europa Clipper—if the numbers work out. "We’re looking even further for collaboration with the science community and the planetary folks," he said. "They are basically baselining SLS as their launch vehicle. We’ll see how we do there." In an effort to promote SLS as a multipurpose rocket, Boeing has spared no expense on artist's concepts that feature planetary exploration missions. They envision the rocket being used for things like a Uranus orbiter, a Voyager-style interstellar probe, and a huge space telescope with an effective diameter of 16 meters.
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The usual suspectsThe Space Launch System has been occasionally referred to as the "Senate Launch System," a swipe at political mandates dictating how and where the rocket should be built. All of the big aerospace players are involved, including Boeing, Lockheed Martin, ATK and Aerojet Rocketdyne. SLS is designed at Marshall Space Flight Center, built at Michoud Assembly Facility, integrated and launched from Kennedy Space Center, and controlled by Johnson Space Center. As the space shuttle program came to a close, politicians in space districts fought to ensure NASA's next rocket system would be built in their backyards. Ironically, some of the Space Launch System's cost savings may come at the expense of people. At Kennedy Space Center, SLS requires a smaller footprint than the space shuttle. Only one Vehicle Assembly Building bay is needed. There is just one mobile launch tower and one launch pad—which lacks the behemoth fixed structures of the shuttle program. Many other shuttle facilities are being rented out or sold. In Louisiana, the Michoud Assembly Facility no longer requires a large, horizontal, indoor facility to build fuel tanks, with the opening of the state-of-the-art Vertical Assembly Center. Is there any road to Mars that doesn't pass through all the familiar space districts? For NASA, not likely. While there are no shortage of ideas on how private companies could do things differently, the recent losses of Antares and SpaceShipTwo are jarring reminders of how difficult spaceflight is—political and budgetary constraints notwithstanding. NASA's commercial resupply program has largely been a success, with both Orbital Sciences Corporation and SpaceX regularly sending cargo to the ISS (Orbital plans to use alternative launch vehicles until Antares returns to flight). In 2017, the agency expects to have either Boeing, SpaceX or both ferrying astronauts to the station. Once NASA has established a staging point in lunar DRO, additional opportunities may arise for commercial providers, such as resupply missions to a habitat module. When asked whether NASA or commercial astronauts will walk on Mars first, May, Cummings and Geyer said they'd be happy in any either case—and that it would likely be a team effort. But at the same time, NASA believes they must be the ones to blaze the trail. "There is no market on Mars," May said. "We're kidding ourselves if we believe that." On to MarsFlash forward to the mid-2030s. At Kennedy Space Center, a crew of astronauts climb into an Orion capsule and launch into space atop SLS. They arrive at lunar DRO, dock with a habitat module, and depart for Mars. They zip through interplanetary space as fast as they can, minimizing their exposure to radiation. In Martian orbit, they meet up with more cargo and equipment. During the first trip, the crew might orbit without landing, Apollo 10-style. Another mission might land on Phobos. But eventually, a crew will plunge into the Martian atmosphere. NASA estimates 15 to 20 tons of equipment will be needed on Mars for a human surface expedition. This includes food, water, air, habitats, rovers, and an ascent vehicle. The biggest thing to land on Mars so far is the one-ton Curiosity rover, which made a harrowing, rocket-powered descent during NASA's highly publicized "seven minutes of terror." Once on Mars, the crew spends up to a year exploring the surface. They return to Martian orbit and depart for Earth. Their transit habitat gets dropped off at lunar DRO for refurbishment, while the crew careens back into Earth's atmosphere aboard Orion and splashes down into the Pacific. There are ticker tape parades for the astronauts. It is a watershed moment for humanity—the end of 60 frustrating years following the last time we dared to do something so staggeringly bold. So why doesn't NASA just say how they're going to do it? Because it's expensive. It's subject to political whims. It's astonishingly difficult. In short, it's crazy. So for now, Gerstenmaier and NASA keep their cards close to the vest. Rather than handing Congress a binder of plans with an astronomical price tag, they focus on short term goals that put the agency one step closer to Mars. |