[Britalian]

Would be curious to know if the Air Force's Delta IV and Atlas V rockets can be used for MANNED spaceflight. (They currently lift satellites) Could these rockets be used, in their present form, to lift astronauts to the International Space Station? Thank You!

[robertva]

While I suppose the technical issues wouldn't be insurmountable, a new manned spacecraft would have to be developed with the mechanical, electrical and other support and control interfaces to those existing launchers.

Note that the one man Mercury orbital missions were launched with an earlier version of the Atlas missile.

NASA is currently developing the Aries I launch vehicle. The Aries I first stage is based on the solid propellant technology used for most unmanned satellite launchers and the space shuttle boosters. The Aries I second stage will use an updated version of the rocket used in the third stage of the Saturn V moon rockets. Much of the added safety will be the result of the Orion spacecraft's position at the top of the vehicle where it will be clear of any ice or insulation shed from cryogenic propellant tanks and able to use a launch escape tower to lift the manned re-entrycapsule (will look like an enlarged Apollo command module) free of a malfunctioning rocket. There may also be safety gains resulting from the use of a single rocket motor on each stage (fewer failure points/Keep It Simple S____ - at least as much as you can with aerospace) and no asymmetrical thrust if some rockets on a stage suffer from reduced thrust.