Space Launch System - SLS
The imaginatively named Space Launch System, or SLS, is intended to provide an entirely new capability for human exploration beyond Earth orbit. It also might back up commercial and international partner transportation services to the International Space Station. Designed to be flexible for crew or cargo missions, the SLS is intended to be safe, affordable, and sustainable, to continue America's journey of discovery from the unique vantage point of space. The SLS will take astronauts farther into space than ever before, while engaging the US aerospace workforce here at on Earth.
The Space Launch System, or SLS, would carry the Orion Multi-Purpose Crew Vehicle, as well as cargo, equipment and science experiments, to deep space. The Orion spacecraft would carry up to four astronauts beyond low Earth orbit on long-duration, deep space missions and include both crew and service modules and a launch abort system to significantly increase crew safety. As NASA’s commercial partners create an American supply line to the International Space Station, SLS will provide the transportation needed for NASA to reach further into our solar system. However, if needed, SLS could support backup transportation to the International Space Station.
SLS will be the most powerful rocket in history and is designed to be flexible and evolvable, to meet a variety of crew and cargo mission needs. The SLS will be NASA’s first exploration-class vehicle since the Saturn V took American astronauts to the moon over 40 years ago. With its superior lift capability, the SLS will expand our reach in the solar system, allowing astronauts aboard the Orion spacecraft to explore multiple, deep-space destinations including near-Earth asteroids, Lagrange points, the moon and ultimately Mars. The SLS heavy-lift launch vehicle is essential to NASA’s deep-space exploration endeavors. The system will be flexible and include multiple launch vehicle configurations. The SLS will carry crew, cargo and science missions to deep space.
The SLS will use proven hardware and cutting-edge tooling and manufacturing technology from the Space Shuttle and other exploration programs. This will significantly reduce development and operations costs. It will use a liquid hydrogen and liquid oxygen propulsion system, which will include the RS-25 engine from the Space Shuttle Program for the core stage and the J-2X engine for the upper stage. The SLS also will use solid rocket boosters for the initial development flights.
The 70-metric-ton- (77 ton) configuration will lift more than 154,000 pounds and will provide 10 percent more thrust than the Saturn V rocket while the 130-metric-ton-(143 ton) configuration will lift more than 286,000 pounds and provide 20 percent more thrust than the Saturn V. The 70-metric-ton SLS will stand 321 feet tall, provide 8.4 million pounds of thrust at liftoff, weigh 5.5 million pounds and carry 154,000 pounds of payload.
The Boeing Co. of Huntsville, AL, is developing the SLS core stage, including its avionics. Towering over 200 feet tall with a diameter of 27.5 feet, the core stage will store cryogenic liquid hydrogen and liquid oxygen that will feed the RS-25 engines for the SLS. The stage is being built at NASA’s Michoud Assembly Facility in New Orleans with state-of-the-art manufacturing equipment. Flight computer hardware and battery unit development are under way. The SLS core stage will get its power from four RS-25 engines — former space shuttle main engines built by Pratt & Whitney Rocketdyne of Canoga Park, Calif. The SLS Program has an inventory of 15 RS-25 flight engines, which operated with 100 percent mission success during 135 space shuttle missions.
A pair of five-segment solid rocket boosters will be used for the first two, 70-metric-ton-flights of the SLS. The prime contractor for the boosters — ATK of Brigham City, Utah — has begun processing its first SLS hardware components in preparation for the initial qualification test planned for spring 2013.
An interim cryogenic propulsion stage would be used on the first two flights of the SLS, based on Boeing’s Delta Cryogenic Second Stage used on the Delta IV family of launch vehicles. The interim cryogenic propulsion stage will boost the Orion spacecraft to the correct altitude and trajectory needed to send the spacecraft around the moon in order to check out vital systems during the initial test flights. The 130-metric-ton-SLS will include an upper stage to provide additional power needed to travel to deep space. The upper stage, built by Boeing, will share common attributes with the core stage such as its outer diameter, material composition, subsystem components and tooling to save cost and design time.
The first SLS mission — Exploration Mission 1 — will launch an Orion spacecraft with no crew to demonstrate the integrated system performance of the SLS rocket and spacecraft prior to a crewed flight. The second SLS mission, Exploration Mission 2, is targeted for 2021 and will launch Orion and a crew of up to four American astronauts.
NASA Associate Administrator for Human Exploration and Operations William Gerstenmaier said 10 December 2014 that NASA pushed back its Space Launch System (SLS) first launch goal to roughly June 2018 from its previous estimate of December 2017.
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