The Space Shuttle Program is scheduled for shutdown sometime in 2010. At that time the reusable, tiled spaceplane concept (STS) will be put to rest in favor of the capsule-on-a-rocket design.  According to plans, there will be a 5 year interlude between the retirement of the shuttle and the implementation of a new man-certified lifter. Many have suggested that this idle period with no manned launch activity could lead to a brain drain in the ranks of skilled aerospace workers.

The successor to STS is the Ares Launch system consisting of a man lifter (Ares I) and a cargo lifter (Ares V).  Ares I is a two-stage system that will take a crew of 4 to 6 into low earth orbit. This vehicle will carry  55,000 lbs of provisions and astronauts to the ISS.  Additionally, it will be used to lift a lunar exploration team into orbit for docking with the lander module placed into orbit by the Ares V lifter. 

Ares V is a heavy lifter and is expected to be able to place 414,000 lbs into low earth orbit or send 157,000 pounds of payload to the moon.  Ares V uses two solid rocket boosters derived from STS and a central H2/O2 liquid fueled rocket using a cluster of 6 engines derived from the Delta IV system.

Ares I & V. Photo Credit- NASA

NASA has awarded contracts for this program and work is underway.

What has recently transpired is an alternative system proposed by a group of engineers. This system is called DIRECT, and involves the use of a single lifter called Jupiter.  The Jupiter lifter is derived directly from the STS lifter which consists of two solid rocket motors and a central H2/O2 tank which feeds the shuttle engines.  The DIRECT system would take advantage of existing technology, but with the addition of an O2 tank extension, a cargo section, and a cluster of engines to the existing liquid fuel tank. The proponents of this system claim that their system could get the next phase of manned space flight going sooner, simpler, and safer.

It is an interesting proposal. I hope it gets some serious consideration by the Congress.