Late last night and early this morning NASA, Congress, the White House - and the media - were all a buzz with the sudden announcement - that there would be an "announcement". After months of subpoenas, contentious hearings, foot dragging, posturing, leaks, and press conferences, NASA, White House, and Congress had finally come to an agreement as to what the congressionally-mandated Space Launch System would look like and how much it would cost.
According to NASA; "The SLS will carry human crews beyond low Earth orbit in a capsule named the Orion Multi-Purpose Crew Vehicle. The rocket will use a liquid hydrogen and liquid oxygen fuel system, where RS-25D/E engines will provide the core propulsion and the J2X engine is planned for use in the upper stage. There will be a competition to develop the boosters based on performance requirements."
NASA and the White House had originally planned to put off a decision on a heavy launch capability until 2015 or so - and then fully compete the selection process based on an architecture that would define what was needed and when. But Congress - specifically the Senate, decided to mandate (in the NASA Authorization Act) what the solution would be before the problem or need was defined. The clear intent on the part of Congress was to retain existing workforce and commercial contracts in place from the Space Shuttle and Constellation programs. That said, with a consensus on the part of White House, NASA - and Congress, at least everyone now knows what NASA's basic evolvable architecture will look like.
This does leave things a little confusing however. This rocket is shown as carrying crew and many members of Congress speaking in press conferences today refered to the rocket as being vital to keeping the ISS runing until 2020. Yet simutaneously NASA is pursuing a commercial approach wherien both crew and cargo services will be procured from the private sector. So, at first blush, this would seem like the government is competing with its own initiatives. Those details are still awaiting clarification.
Sources suggest that the ISS role is actually far smaller than some in Congress would have you think, and that the real intent is to focus this rocket on deep space and planetary missions. Indeed, in addition to the crewed version, a cargo version is also shown in new NASA materials released today. The clear intent is to make the rocket bigger - much bigger than anything that the private sector has offered up.
The SLS will feature a 8.4 meter core stage - the same diamater as the recently retired Space Shuttle system. This allows a whole host of existing Shuttle manufacturing and ground systems to be reused or easily adapted. Initially there will be three Shuttle main engines on the first stage with five used at some point in the future for heavier launch capabilities. The upper stage will be the same diameter as the first stage which allows commonality in construction. There is an intent on NASA's part of having a common manufacturer for the first and second stage.
The 70 mt SLS will have 10% more thrust at liftoff than a Saturn V. The 130 mt variant will have 20% more thrust. The 70 mt variant is a little shorter than Saturn V and the 130 mt variant will be 40 feet taller than a Saturn V.
The interesting part of all of this is going to be when and how NASA opens up portions of the SLS to open compeition. Right now the basic vehicle uses standard ATK solid rocket boosters. These strap-ons are among the main items to be upgraded as part of the evolution of the SLS's launch capacity.
In a press conference, William Gerstenmaier, associate administrator for NASA's Human Exploration and Operations said that the first stage will be designed from the onset to accept a variety or range of strap-on boosters. When asked when that procurement will begin, Gerstenmaier said that this "wIll begin almost immediately - competition begins as soon as we go do this [procurement] activity."
Sen. Kay Baily Hutchison said in a press conference a few hours earlier that the exisiting Constellation and shuttle contracts will be changed within a week or so. When asked about this Gerstenmaier said that will not happen that fast. He said that NASA's intent is to have an Industry day for the private sector around 29 September. A formal synopisis will be issued at the end of this week announcing that event.
Of course, while SLS is on the drawing board, SpaceX, Boeing, Orbital, Lockheed Martin and others will actually be flying commmerical rockest and/or spacecraft to the ISS and Low Earth Orbit - and perhaps beyond. SpaceX has not been at all shy about heavy lift variants of its Falcon 9 rocket and even have their eyes set upon landing Dragon spacecraft on Mars.
The graphics released by NASA clearly evoke memories of the Saturn V by virtue of the white and black scheme that is shown. This visual depiction also differentiates the SLS it from its half-brother, the cancelled Ares V which featured the orange paint scheme associated with the Space Shuttle's external tank. Of course, Ares V was always shown with shuttle colors so as to evoke the shuttle-derived theme i.e. that it used Shuttle parts. Gerstenmaier said today "this is not rocket built from Shuttle parts - components will be used in a new and novel way." Clearly, computer graphics are now part of the political and sales mesage at NASA.
Of course, what is still lacking in this whole story is exactly what NASA will do with this big rocket. Missions to asteroids, Mars etc. are often tossed out by NASA representatives - but no timeline whatosever has yet to be presented - not even a "notional" one. Nor has an overall strategy or architecture been issued or any idea what the cost would be for the things that would actually fly on these rockets.
Keith's note: Contrary to what some websites are reporting (including this one) NASA PAO says that the white/black coloration of the SLS stages that evokes memories of the Saturn V is there for the same reason: to aid in tracking during ascent. There will be no spray-on foam on the first (or second stage ) as was the case with the Space Shuttle and Ares V - hence no orange on the SLS.