A Chariot for Orion
To loft this bigger, heavier spacecraft, NASA needed a behemoth launch vehicle (LV). With Constellation gone, none of the commercial entries could do so. But, it seems NASA Administrator Charles Bolden may be descended from Mississippi riverboat gamblers. He was holding an ace in the hole. He had fulfilled Obama's directive to give private firms the task of launching Americans and cargo into space in 2010 and this year (see below). The 2012 budget gave him the go-ahead to design and develop the giant LV needed for ORION.
The result is the Space Launch System, or SLS. This will be the most powerful rocket ever launched. Built from uprated parts of the Space Shuttle, it will have a liftoff thrust, with strap-on solid rocket Boosters (SRB) similar to the Shuttle's, of more than eight million pounds. Later versions will have more than 10 million lbs of thrust. This power will give the SLS the ability to put 70 tons into low Earth orbit (LEO) with the initial design, and 130 tons with the later, two stage version.
In the drawing above, the version on the left shows the Orion spacecraft atop the SLS. On the right is the so called 'cargo version. This also is the LV that will be able to send Orion, and astronauts, back to the Moon, and beyond.
The first stage uses five uprated Shuttle main engines (the Shuttle had three) with LH2/LOX propellant. The SRBs are like the Shuttle''s, but more powerful. On the smaller version, there is no need for a second stage, as the propellant combination provides a long burn and high exhaust velocity. In effect, the SLS is like the old ATLAS LV—a stage and 1/2 vehicle.
The large version has a second stage, again with LH2/LOX propellant. The engine is a new model of the Saturn V second and third stage engine with almost 300,000 lbs of thrust. It is restartable and so can put Orion into translunar, trans-asteroid or trans-Mars injection.
But the beyond the Moon missions would not be 'all up' like the lunar missions of the Saturn V. Instead, two or three different spacecraft would be launched into orbit by different LVs and hook up for escape from Earth. Bolden would soon have this covered as well.