The Obama administration’s Fiscal 2011 NASA budget retargets agency funding on developing a U.S. commercial space-transportation industry, killing the “Moon, Mars and Beyond” Constellation Program in favor of a $6 billion “investment” in human-rating existing launch vehicles and developing a common crew vehicle to ride on them all.

The space shuttle is retired after the five flights remaining on the manifest, and the International Space Station is extended at least to 2020, with $2 billion in additional funding over four years to boost its role as a U.S. National Laboratory.

In lieu of the focused effort to return to the Moon by 2020 laid out in the Constellation Program, the agency wants to spend about $1 billion a year over the next five years on “game-changing” space-technology development for U.S. government and commercial use, and mount a relatively modest program of robotic precursor missions to the Moon, Mars and its moons, close-in asteroids and the Lagrange points. The goal would be “to scout targets for future human activities, and identify the hazards and resources that will determine the future course of the expansion of human civilization into space.”

In general, those missions will cost less than $800 million each, in total. Possibilities include a teleoperated robotic lunar lander, and a demonstration in situ resource utilization system on the Moon or an asteroid.

“Today we are launching a bold and ambitious new space initiative to enable us to explore new worlds, develop more innovative technologies, foster new industries, increase our understanding of the Earth, expand our presence in the solar system, and inspire the next-generation of explorers,” states Administrator Charles Bolden in the charts he will use to explain the budget request.

Bolden is scheduled to speak to reporters in a budget teleconference beginning at 12:30 EST, while Lori Garver — his deputy — and Presidential Science Adviser John Holdren have a 1 p.m. press conference scheduled to place the NASA request in context with broader administration research and development spending plans.

At a second press conference on Tuesday, Holdren and Bolden will “introduce new commercial space pioneers, launching a game-changing way of developing technology to send humans to space.”

The budget request follows many of the recommendations of the human-spaceflight review panel headed by former Lockheed Martin CEO Norman Augustine. But while NASA’s budget would get a $6 billion increase over the next five years, the request falls short of the $3 billion annual increase the Augustine panel said would be needed to fund meaningful human exploration beyond low Earth orbit.

It also would fund a large increase in Earth-science research from space, in keeping with the administration’s emphasis on addressing climate change. After adding $382 million to the Fiscal 2010 spending level, it would add another $1.8 billion to the Earth-science budget through Fiscal 2014. It would build and launch another Orbiting Carbon Observatory (OCO) to replace the one lost on launch last year. The OCO was designed to map carbon dioxide concentrations in the atmosphere worldwide, improving scientific understanding of the sources of the greenhouse gas when combined with ground observations.

While the budget drops the Ares I crew launch vehicle and its Ares V heavy-lift follow-on, it contains about $560 million - $600 million in funding over the life of the budget for heavy-lift launcher technology development, including “new approaches to first-stage launch propulsion” and basic propulsion research handled by the Exploration Systems Mission Directorate. That is roughly the same spending level the budget contains for “aeronautics and green aviation,” which includes $30 million a year to begin integrating unmanned aircraft into the U.S. airspace.