The countdown begins: Nasa set to approve design for the biggest rocket ever made - and say it will one day take man to Mars
- Construction of the Space Launch System has already begun
- Rocket will eventually be 384 feet tall and weigh 6.5 million pounds
- Will be powered by four RS-25 engines - previously used to send space shuttle into orbit
Nasa's Space Launch System (SLS) will be the most powerful launch vehicle ever built.
The space agency is this week beginning a major 'critical design review' that will see the blueprints for the giant rocket being signed off within weeks.
The critical design review May 11 at NASA's Marshall Space Flight Center in Huntsville, Alabama
'We've never said building a rocket is easy,' said SLS Program Manager Todd May.
'We pore over every part of this rocket during these reviews.
'Thousands of documents and months of time are put into making sure the design is sound, safe and sustainable, and will make NASA's mission of furthering human spaceflight possible.
'We are making advances every day on this vehicle.'
Each element for the rocket - including boosters, engines, stages and Spacecraft and Payload Integration & Evolution (SPIE) - undergo their own reviews before this week's kickoff of the integrated program review.
Boosters, stages and engines have passed their critical design reviews, and the SPIE Office is in the process of completing its critical design review
The first flight test of the SLS will be configured for a 70-metric-ton (77-ton) lift capacity and carry an uncrewed Orion spacecraft beyond low-Earth orbit to test the performance of the integrated system.
As the SLS evolves, it will be the most powerful rocket ever built and provide an unprecedented lift capability of 130 metric tons (143 tons) to enable missions even farther into our solar system.
The giant engines have already been fired at Nasa's Stennis Space Centre near Bay St. Louis, Mississippi.
The RS-25, formerly the space shuttle main engine, fired up for 500 seconds on the A-1 test stand at Stennis, providing NASA engineers critical data on the engine controller unit and inlet pressure conditions.
This is the first hot fire of an RS-25 engine since the end of space shuttle main engine testing in 2009.
Four RS-25 engines will power SLS on future missions, including to an asteroid and Mars.
Scheduled for its initial test flight in 2017, the SLS is designed to be flexible and evolvable to meet a variety of crew and cargo mission needs.
The initial flight-test configuration will provide a 77-ton capacity, and the final evolved two-stage configuration will provide a lift capability of more than 143 tons.
The rocket will be used to ferry astronauts to the International Space Station, and to help us explore the outer reaches of the solar system.
'The potential use of SLS for science will further enhance the synergy between scientific exploration and human exploration,' said John Grunsfeld, astronaut and associate administrator for science at NASA Headquarters in Washington.
'SLS has the promise of enabling transformational science in our exploration of the solar system and cosmos.'
Nasa has made major modification to the shuttle engines for its new role.
'We've made modifications to the RS-25 to meet SLS specifications and will analyze and test a variety of conditions during the hot fire series,' said Steve Wofford, manager of the SLS Liquid Engines Office at NASA's Marshall Space Flight Center in Huntsville, Alabama, where the SLS Program is managed.
'The engines for SLS will encounter colder liquid oxygen temperatures than shuttle; greater inlet pressure due to the taller core stage liquid oxygen tank and higher vehicle acceleration; and more nozzle heating due to the four-engine configuration and their position in-plane with the SLS booster exhaust nozzles.'
Testing will resume in April after upgrades are completed on the high pressure industrial water system, which provides cool water for the test facility during a hot fire test.
Eight tests, totaling 3,500 seconds, are planned for the current development engine.
Another development engine later will undergo 10 tests, totaling 4,500 seconds.
The second test series includes the first test of new flight controllers, known as green running.
The first flight test of the SLS will feature a configuration for a 70-metric-ton (77-ton) lift capacity and carry an uncrewed Orion spacecraft beyond low-Earth orbit to test the performance of the integrated system.
As the SLS is upgraded, it will provide an unprecedented lift capability of 130 metric tons (143 tons) to enable missions even farther into our solar system. Nasa has signed a $2.8 billion contract with Boeing to build the giant rocket it is hoped will take us into deep space.
'Our teams have dedicated themselves to ensuring that the Space Launch System (SLS) – the largest ever - will be built safely, affordably and on time,' said Virginia Barnes, Boeing SLS vice president and program manager.
'We are passionate about NASA's mission to explore deep space.
'It's a very personal mission, as well as a national mandate.'
This milestone marks NASA's first CDR on a deep-space human exploration launch vehicle since 1961, when the Saturn V rocket underwent a similar design review as the United States sought to land an astronaut on the moon.
Currently under construction, NASA's Space Launch System will be the world's most powerful launch vehicle.
Designed to enable human exploration missions to deep space destinations, including an asteroid and Mars, SLS is working toward a first launch in 2017.
For that first flight test, the rocket will be able to launch 70 metric tons (77 tons) of payload into low-Earth orbit, almost three times what the space shuttle could carry.
From there, SLS will be evolved to a configuration that will be able to carry 130 metric tons (143 tons), more weight than any rocket ever has been able to carry.
'While many people think of the Space Launch System in terms of human exploration, SLS could have a wide application in a lot of other areas, including space science,' said Steve Creech, assistant program manager for strategy and partnerships for SLS.
'For missions to the outer planets, for example, SLS could make it possible to do things that are currently impossible, such as sending larger scientific spacecraft with more instruments to far off destinations with reduced transit times.'
Agency scientific and engineering teams have been evaluating whether there would be potential benefits from launching deep space robotic spacecraft, such as the Europa Clipper, a proposed mission to one of Jupiter's icy moons, on the SLS rocket, and determined the rocket would enable the spacecraft to fly direct trajectories to our solar system's outer planets, rather than using planetary gravities to gain speed, reducing transit time compared to current launch vehicles.
In the case of the Europa Clipper, for example, the transit time would be reduced to less than half of what it would be using other launch vehicles.
'For as long as people have been launching rockets into space, mission designers have had to work within certain limitations – a spacecraft can only be so heavy and it has to fit within a certain width,' Creech said.
'Depending on how large you make it, it can only go so fast, which in some cases limits where you can go. 'Today, if you want to send a mission to the outer planets, you have to be able to make it fit within that box. With SLS, we're about to make that box much larger. 'With the space shuttle, for example, we were able to launch missions like NASA's Hubble Space Telescope that were about the size of a school bus.
'With SLS, you can design a spacecraft even larger than the space shuttle that carried Hubble.
'It's going to open up an entirely new way of thinking about how we plan and design planetary science missions.'
'The Space Launch System could be really game-changing for space science,' said ACO manager Reggie Alexander.
'For some missions, it makes it much easier and quicker to carry them out.
'A Mars sample return mission, for example, could be flown using only one rocket instead of three.
'But for other destinations, SLS lets you do things we could only dream of before – like collecting samples from the geysers of Saturn's moon Enceladus.'