National Aeronautics and 

Space Administration

The Vision 

for Space

Exploration

February 2004
“This cause of exploration and discovery is not an

option we choose; it is a desire written in the human

heart.”

President George W. Bush

February 4, 2003

“We leave as we came, and God willing as we shall

return, with peace and hope for all mankind.”

Eugene Cernan (Commander of last Apollo mission)

December 17, 1972

“. . . America will make those words 

come true.”

President George W. Bush

January 14, 2004
Message from 

the NASA Administrator

Dear Reader,

With last year’s budget, NASA released a new Strategic Plan outlining a

new approach to space exploration using a “building block” strategy to

explore scientifically valuable destinations across our solar system. At

the same time that we released the Strategic Plan, our Nation and the

NASA family also suffered the loss of the seven brave astronauts aboard

the Space Shuttle Columbia. The report of the Columbia Accident

Investigation Board emphasized the need for a clearer direction from

which to drive NASA’s human exploration agenda. On January 14,

2004, the President articulated a new vision for space exploration.

You hold in your hands a new, bolder framework for exploring our solar system that builds upon the policy

that was announced by the President after months of careful deliberations within the Administration. This

plan does not undertake exploration merely for the sake of adventure, however exciting that may be, but

seeks answers to profound scientific and philosophical questions, responds to recent discoveries, will put in

place revolutionary technologies and capabilities for the future, and will genuinely inspire our Nation, the

world, and the next generation.

Our aim is to explore in a sustainable, affordable, and flexible manner. We believe the principles and

roadmap set down in this document will stand the test of time. Its details will be subject to revision and

expansion as new discoveries are made, new technologies are applied, and new challenges are met and overcome. This plan is guided by the Administration’s new space exploration policy, “A Renewed Spirit of

Discovery: The President’s Vision for U.S. Space Exploration,” a copy of which is provided on the following pages. NASA is releasing this plan simultaneously with NASA’s FY 2005 Budget Justification. This

plan is fiscally responsible, consistent with the Administration’s goal of cutting the budget deficit in half

within the next five years.

I cannot overstate how much NASA will change in the coming years as this plan is implemented. I also cannot overstate how profound the rewards will be on this new course. With the support of Congress, the science community, the NASA civil and contractor workforce, and most importantly, the American public, we

will embark on this very exciting future.

When Christopher Columbus made his voyages across the Atlantic in the 15th and 16th centuries, his ships

carried the inscription “Following the light of the sun, we left the Old World.” I look forward to joining you

as we follow the light of the planets and the stars into the new worlds of the 21st century.

Sean O'Keefe

Administrator
Top image: The Mars Exploration Rover Opportunity’s view of Mars’

Meridiani Planum, taken with the panoramic camera. Lower image:

Opportunity looks back at its empty lander as it begins to explore

Meridiani Planum.
A Renewed Spirit of Discovery: 

The President’s Vision 

for U.S. Space Exploration

Background

From the Apollo landings on the Moon, to robotic surveys of the Sun and the planets, to the compelling

images captured by advanced space telescopes, U.S. achievements in space have revolutionized humanity’s

view of the universe and have inspired Americans and people around the world. These achievements also

have led to the development of technologies that have widespread applications to address problems on Earth.

As the world enters the second century of powered flight, it is time to articulate a new vision that will define

and guide U.S. space exploration activities for the next several decades.

Today, humanity has the potential to seek answers to the most fundamental questions posed about the existence of life beyond Earth. Telescopes have found planets around other stars. Robotic probes have identified

potential resources on the Moon, and evidence of water -- a key ingredient for life -- has been found on Mars

and the moons of Jupiter.

Direct human experience in space has fundamentally altered our perspective of humanity and our place in

the universe. Humans have the ability to respond to the unexpected developments inherent in space travel

and possess unique skills that enhance discoveries. Just as Mercury, Gemini, and Apollo challenged a generation of Americans, a renewed U.S. space exploration program with a significant human component can

inspire us -- and our youth -- to greater achievements on Earth and in space.

The loss of Space Shuttles Challenger and Columbia and their crews are a stark reminder of the inherent

risks of space flight and the severity of the challenges posed by space exploration. In preparation for future

human exploration, we must advance our ability to live and work safely in space and, at the same time,

develop the technologies to extend humanity’s reach to the Moon, Mars, and beyond. The new technologies

required for further space exploration also will improve the Nation’s other space activities and may provide

applications that could be used to address problems on Earth.

Like the explorers of the past and the pioneers of flight in the last century, we cannot today identify all that

we will gain from space exploration; we are confident, nonetheless, that the eventual return will be great.

Like their efforts, the success of future U.S. space exploration will unfold over generations.

Goal and Objectives

The fundamental goal of this vision is to advance U.S. scientific, security, and economic interests through a

robust space exploration program. In support of this goal, the United States will:

• Implement a sustained and affordable human and robotic program to explore the solar system and 

beyond;

• Extend human presence across the solar system, starting with a human return to the Moon by the year

2020, in preparation for human exploration of Mars and other destinations;

• Develop the innovative technologies, knowledge, and infrastructures both to explore and to support

decisions about the destinations for human exploration; and

• Promote international and commercial participation in exploration to further U.S. scientific, security,

and economic interests.
Bringing the Vision to Reality

The Administrator of the National Aeronautics and Space Administration will be responsible for the plans,

programs, and activities required to implement this vision, in coordination with other agencies, as deemed

appropriate. The Administrator will plan and implement an integrated, long-term robotic and human exploration program structured with measurable milestones and executed on the basis of available resources, accumulated experience, and technology readiness.

To implement this vision, the Administrator will conduct the following activities and take other actions as

required:

A. Exploration Activities in Low Earth Orbit

Space Shuttle

• Return the Space Shuttle to flight as soon as practical, based on the recommendations of the Columbia

Accident Investigation Board;

• Focus use of the Space Shuttle to complete assembly of the International Space Station; and

• Retire the Space Shuttle as soon as assembly of the International Space Station is completed, planned 

for the end of this decade;

International Space Station

• Complete assembly of the International Space Station, including the U.S. components that support

U.S. space exploration goals and those provided by foreign partners, planned for the end of this 

decade;

• Focus U.S. research and use of the International Space Station on supporting space exploration goals,

with emphasis on understanding how the space environment affects astronaut health and capabilities

and developing countermeasures; and

• Conduct International Space Station activities in a manner consistent with U.S. obligations contained 

in the agreements between the United States and other partners in the International Space Station.

B. Space Exploration Beyond Low Earth Orbit

The Moon

• Undertake lunar exploration activities to enable sustained human and robotic exploration of Mars and

more distant destinations in the solar system;

• Starting no later than 2008, initiate a series of robotic missions to the Moon to prepare for and support

future human exploration activities;

• Conduct the first extended human expedition to the lunar surface as early as 2015, but no later than 

the year 2020; and 

• Use lunar exploration activities to further science, and to develop and test new approaches,

technologies, and systems, including use of lunar and other space resources, to support sustained 

human space exploration to Mars and other destinations.
Mars and Other Destinations

• Conduct robotic exploration of Mars to search for evidence of life, to understand the history of the 

solar system, and to prepare for future human exploration;

• Conduct robotic exploration across the solar system for scientific purposes and to support human

exploration. In particular, explore Jupiter’s moons, asteroids and other bodies to search for evidence

of life, to understand the history of the solar system, and to search for resources;

• Conduct advanced telescope searches for Earth-like planets and habitable environments around other

stars;

• Develop and demonstrate power generation, propulsion, life support, and other key capabilities 

required to support more distant, more capable, and/or longer duration human and robotic exploration

of Mars and other destinations; and

• Conduct human expeditions to Mars after acquiring adequate knowledge about the planet using 

robotic missions and after successfully demonstrating sustained human exploration missions to the 

Moon.

C. Space Transportation Capabilities Supporting Exploration

• Develop a new crew exploration vehicle to provide crew transportation for missions beyond low Earth

orbit;

« Conduct the initial test flight before the end of this decade in order to provide an operational 

capability to support human exploration missions no later than 2014;

• Separate to the maximum practical extent crew from cargo transportation to the International Space

Station and for launching exploration missions beyond low Earth orbit; 

« Acquire cargo transportation as soon as practical and affordable to support missions to and from 

the International Space Station; and 

« Acquire crew transportation to and from the International Space Station, as required, after the

Space Shuttle is retired from service.

D. International and Commercial Participation

• Pursue opportunities for international participation to support U.S. space exploration goals; and

• Pursue commercial opportunities for providing transportation and other services supporting the 

International Space Station and exploration missions beyond low Earth orbit.

PRESIDENT GEORGE W. BUSH

JANUARY 14, 2004

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

NASA Guiding Principles for Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Solar System and Beyond—Exploration Roadmap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Lunar Testbeds and Missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Mars Research, Testbeds, and Missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Outer Moons Research and Missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Extrasolar Planet Research and Observatories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Exploration Building Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

NASA Transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

National Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Table of Contents

Left: An artist’s concept of a spacecraft, equipped with a centrifuge

and nuclear–electric propulsion, traveling to Mars.
National Aeronautics and

Space Administration 2

Introduction

“The American experience stirred mankind from discovery to exploration. From the 

cautious question of what they knew was out there . . . into an enthusiastic reaching 

to the unknown.”

Daniel J. Boorstin (1914– )

“Somewhere, something incredible is waiting to be known.”

Carl Sagan (1934–1996)

Understanding from the unknown. Comprehension

from the cosmos. Insight from the infinite. The relationship between discovery and exploration has driven human curiosity for all of recorded history. Since

the time of the ancient philosophers, we have striven

to comprehend our place in the universe and have

looked to the heavens for answers to the questions:

Where do we come from? Are we alone? Where are

we going?

Exploration and discovery have been especially

important to the American experience. New World

pioneers and American frontiersmen showed our

Nation the importance of the knowledge, technology, resources, and inspiration that flow from exploration. Like the ancients, America has also explored

the heavens, and in the latter half of the 20th century, the Apollo Moon landings became the most distant milestone in the continuing American exploratory tradition.

At the beginning of the 21st century, we stand at a

unique time in our exploration of the heavens. The

exploratory voyages of the next few decades have

the potential—within our lifetimes—to answer ageold questions about how life begins, whether life

exists elsewhere, and how we could live out there.

Our understanding of the universe and its habitability is being revolutionized by new discoveries.

Scientists have found new forms of life in environments once thought inhospitable. Spacecraft have

identified potential new resources on the Moon.

Robotic probes have found evidence of water, a key

ingredient of life, on the planet Mars. A mission to

Jupiter has revealed that oceans likely underlay the

icy surfaces of that planet’s moons. Astronomers

have discovered over 100 planets, and counting, circling other stars. Together, these findings indicate

that our universe may be more habitable than previously known. Instead of a dry, lifeless universe,

there may be many worlds that harbored life in the

past and can support life today.

We also stand at a pivotal time in the history of

human space flight, when important choices about

investments in the Space Shuttle, the International

Space Station, and follow-on programs are being

made in the wake of the Space Shuttle Columbia

tragedy. Just as decisions to begin the Space Station

and Space Shuttle programs were made 20 and 30

years ago, the direction we set for our human space

flight programs today will define space exploration

for decades to come.

The President’s Vision for space exploration is bold

and forward-thinking. It expands scientific discovery and the search for habitable environments and

life by advancing human and robotic capabilities

across multiple worlds. This plan provides the

framework for fulfilling the President’s direction,

guided by the principles on the facing page. It is

responsive to recent science findings, the NASA

Strategic Plan, the report of the Columbia Accident

Investigation Board, and the new space exploration

policy. It seeks to establish a sustainable and flexible approach to exploration by pursuing compelling

questions, developing breakthrough technologies,

leveraging space resources, and making smart decisions about ongoing programs. It will help drive

critical national technologies in power, computing,

nanotechnology, biotechnology, communications,

networking, robotics, and materials. It will start

exciting new programs now to inspire the next generation of explorers.

Our generation inherited great legacies from the

exploratory voyages and discoveries of earlier centuries. Starting with an exploration roadmap (see

page 4), this document outlines a plan for achieving

great legacies that our century can leave to future

generations.
3 The Vision for 

Space Exploration

NASA Guiding Principles for Exploration

Pursue Compelling Questions

Exploration of the solar system and beyond will be guided by compelling questions of scientific and societal importance. NASA exploration programs will seek profound answers to questions about the origins of

our solar system, whether life exists beyond Earth, and how we could live on other worlds.

Across Multiple Worlds

NASA will make progress across a broad front of destinations, starting with a return to the Moon to enable

future human exploration of Mars and other worlds. Consistent with recent discoveries, NASA will focus

on possible habitable environments on Mars, the moons of Jupiter, and in other solar systems. Where advantageous, NASA will also make use of destinations like the Moon and near-Earth asteroids to test and demonstrate new exploration capabilities.

Employ Human and Robotic Capabilities

NASA will send human and robotic explorers as partners, leveraging the capabilities of each where most useful. Robotic explorers will visit new worlds first, to obtain scientific data, assess risks to our astronauts,

demonstrate breakthrough technologies, identify space resources, and send tantalizing imagery back to

Earth. Human explorers will follow to conduct in-depth research, direct and upgrade advanced robotic

explorers, prepare space resources, and demonstrate new exploration capabilities. 

For Sustainable Exploration

NASA will pursue breakthrough technologies, investigate lunar and other space resources, and align ongoing programs to develop sustainable, affordable, and flexible solar system exploration strategies.

Use the Moon as a Testing Ground For Mars and Beyond

Under this new Vision, the first robotic missions will be sent to the Moon as early as 2008 and the first

human missions as early as 2015 to test new approaches, systems and operations for sustainable human and

robotic missions to Mars and beyond.

Starting Now

NASA will pursue this Vision as our highest priority. Consistent with the FY 2005 Budget, NASA will

immediately begin to realign programs and organization, demonstrate new technical capabilities, and undertake new robotic precursor missions to the Moon and Mars before the end of the decade.
National Aeronautics and

Space Administration 4

NOTE: All missions indicate launch dates.
5 The Vision for 

Space Exploration

Solar System and Beyond— 

Exploration Roadmap

Over the next three decades, NASA will send robotic probes to explore

our solar system, including our Earth’s Moon, the planet Mars, the

moons of Jupiter and other outer planets, and will launch new space telescopes to search for planets beyond our solar system. These robotic

explorers will pursue compelling scientific questions, demonstrate

breakthrough technologies, identify space resources, and extend an

advanced telepresence that will send stunning imagery back to Earth.

Starting at the Moon in 2008 and at Mars in 2011, NASA will launch

dedicated robotic missions that will demonstrate new technologies and

enhance our scientific knowledge of these destinations. These new

technologies and discoveries will pave the way for more capable robotic missions and eventually human missions. The first human explorers

will be sent to the Moon as early as 2015, as a stepping stone to demonstrate sustainable approaches to exploring Mars and other worlds. 

To support these missions, a number of key building blocks are necessary. These include new capabilities in propulsion, power, communications, crew transport, and launch, as well as the refocusing of ongoing

programs like Space Station research. Major achievements, including

the completion of Space Station assembly, test flights of new crew

transport capabilities, and space technology demonstrations, are expected before the end of this decade.

The activities in each of the sections in this roadmap, Moon, Mars,

Outer Moons, Extrasolar Planets, and Exploration Building Blocks, are

described in detail on the following pages. Sections describing changes

in the NASA organization and resources to implement this plan are also

included.

Right: The International Space Station as seen

from the Shuttle Endeavour.
National Aeronautics and

Space Administration

6

Facing page, left: Astronaut Nancy Currie, wearing an advanced, lightweight

spacesuit, works with NASA’s Robonaut, a robotic assistant for space exploration. Facing page, right: A false-color mosaic taken by Galileo. Researchers

use the different colors to determine the mineral composition of the lunar surface. Above: An artist’s concept of lunar exploration.
7 The Vision for 

Space Exploration

Lunar Testbeds and Missions

“The moon is a silver pin-head vast,

That holds the heaven’s tent-hangings fast.”

William R. Alger (1823–1905)

“The Use of the Moon,” Oriental Poetry

During the late 1960s and early 1970s, the Apollo

program demonstrated American technical strength

in a race against the Soviet Union to land humans on

the Moon. Today, NASA’s plans for a return to the

Moon are not driven by Cold War competition, but

by the need to test new exploration technologies and

skills on the path to Mars and beyond. Additionally,

during the 1990s, robotic missions identified potential evidence of water ice at the Moon’s poles, a

resource that could make exploration further into the

solar system easier to conduct.

NASA will begin its lunar testbed program with a

series of robotic missions. The first, an orbiter to

confirm and map lunar resources in detail, will

launch in 2008. A robotic landing will follow 

in 2009 to begin demonstrating capabilities for sustainable exploration of the solar system. Additional

missions, potentially up to one a year, are planned to

demonstrate new capabilities such as robotic networks, reusable planetary landing and launch systems, pre-positioned propellants, and resource

extraction.

A human mission to the Moon will follow these

robotic missions as early as 2015. The Moon will

provide an operational environment where we can

demonstrate human exploration capabilities within

relatively safe reach of Earth. Human missions to

the Moon will serve as precursors for human missions to Mars and other destinations, testing new

sustainable exploration approaches, such as space

resource utilization, and human-scale exploration

systems, such as surface power, habitation and life

support, and planetary mobility. The scope and

types of human lunar missions and systems will be

determined by their support to furthering science,

developing and testing new approaches, and their

applicability to supporting sustained human space

exploration to Mars and other destinations.

The major focus of these lunar activities will be 

on demonstrating capabilities to conduct sustained

research on Mars and increasingly deep and more

advanced exploration of our solar system.

Additionally, these robotic and human missions will

pursue scientific investigations on the Moon, such 

as uncovering geological records of our early solar

system.
National Aeronautics and

Space Administration

8

Facing page, left: Gullies on Mars, like this one in the Newton Basin, may have

been formed by groundwater in geologically recent times. Facing page, right:

The Mars Science Lander will land the roving Mars Science Laboratory on the

surface of Mars. Above: A drawing of astronauts and robots exploring Mars.
9 The Vision for 

Space Exploration

Mars Research, Testbeds, and Missions

“We shall never cease from exploration

And the end of all our exploring

Will be to arrive where we started

And know the place for the first time.”

T.S. Eliot (1888–1965)

As early as the 19th century, telescope observations

led some astronomers to speculate that Mars might

harbor life. Subsequent robotic missions to Mars

during the 1960s and 1970s showed that the surface

of Mars is currently inhospitable. However, more

recent missions have transformed our understanding

of Mars. New data indicates that liquid water likely

flowed across the surface of Mars in the distant past

and may still exist in large reservoirs deep underground. This raises the prospect that simple forms of

life may have developed early in Mars’ history and

may persist beneath the surface of Mars to this day.

NASA is aggressively pursuing the search for water

and life on Mars using robotic explorers. The Spirit

and Opportunity rovers that landed on Mars in

January 2004 are the latest in a series of research

missions planned to explore Mars through 2010. By

the end of this decade, three rovers, a lander, and two

orbiters will have visited the planet. NASA will augment this program and prepare for the next decade of

Mars research missions by investing in key capabilities to enable advanced robotic missions, such as

returning geological samples from Mars or drilling

under the surface of Mars. This suite of technologies

will enable NASA to rapidly respond to discoveries

this decade and pursue the search for water and life

at Mars wherever it may lead next decade.

Starting in 2011, NASA will also launch the first in

a new series of human precursor missions to Mars.

These robotic testbeds will demonstrate technologies—such as improved aerodynamic entry, Mars

orbital rendezvous and docking, precision landing,

resource extraction and utilization, and optical communications—that can greatly enhance future robotic capabilities and are key to enabling future human

Mars missions. These missions will also obtain critical data for future human missions on chemical hazards, resource locations, and research sites. They

may prepare resources and sites in anticipation of

human landings.

The first human mission beyond the Moon will be

determined on the basis of available resources, accumulated experience, and technology readiness.

Potential candidates that might be considered

include circumnavigating Mars, visiting a near-Earth

asteroid, or erecting or upgrading a deep space telescope. Such missions could test the human-scale

power, propulsion, and other transit systems necessary to take trips to Mars before taking on the additional risk of a landing on Mars.

The timing of the first human research missions to

Mars will depend on discoveries from robotic

explorers, the development of techniques to mitigate

Mars hazards, advances in capabilities for sustainable exploration, and available resources.
Facing page, left: An artist’s rendering of the Jupiter Icy Moons Orbiter. Facing

page, right: An artist’s drawing of icy bodies in the Kuiper Belt. Above: Jupiter

and its moons Europa (seen against Jupiter) and Callisto (lower left) as seen

by the Cassini spacecraft in 2000.

National Aeronautics and

Space Administration 10
Outer Moons Research and Missions

“Sometimes I think we're alone in the universe, and sometimes I think we're not.

In either case the idea is quite staggering.”

Arthur C. Clarke (1917– )

In 1610, the Italian astronomer Galileo Galilei 

discovered that four large moons circle the planet

Jupiter. In the 1970s, NASA’s twin Voyager missions flew by Jupiter and confirmed that three of

these moons—Europa, Callisto, and Ganymede—

are covered in water ice. Twenty years later, another NASA mission to Jupiter named after Galileo

found evidence that enormous, planet-wide oceans

likely lay underneath the icy surfaces of these

moons. As on Mars, the presence of liquid water

raises the prospect that life could have developed on

one or more of these moons and may still swim in

their oceans today.

NASA is in the early stages of planning a mission

that will visit Europa, Callisto, and Ganymede during the next decade. Unlike the Voyager and Galileo

missions, which could only briefly fly by Jupiter’s

moons, the Jupiter Icy Moons Orbiter will be

designed to circle each moon for up to a year, carrying revolutionary science instruments. This will

allow the lengthy and detailed investigations necessary to confirm and map the underground oceans of

these worlds in detail.

The Jupiter Icy Moons Orbiter is enabled by Project

Prometheus, NASA’s program to develop space

nuclear power and propulsion technology. The

nuclear power and nuclear-electric propulsion technologies that support this mission are also key to

enabling other advanced robotic missions and

human missions beyond Earth’s orbit. In addition to

mapping new oceans, the systems on the Jupiter Icy

Moons Orbiter will be a forerunner of the systems

needed to send humans to other worlds, to supply

power for human expeditions on these worlds, and to

pursue other challenging robotic science missions. 

The moons of other planets in our outer solar system

may also hold critical clues to the evolution of habitable environments and the development of life.

NASA’s Cassini mission, currently on its way to

Saturn, will encounter Saturn’s largest moon, Titan,

next January. Titan is icy like Jupiter’s moons, but

unlike Europa, Callisto, and Ganymede, Titan has an

atmosphere that is about as dense as Earth’s, is composed of many of the same chemicals as Earth’s

early atmosphere, and is believed to contain complex, pre-biotic chemistry. Titan may turn out to be

a key laboratory for understanding how biology arises from chemistry.

Depending on the results from Cassini and the

Jupiter Icy Moons Orbiter, NASA experts believe

that advanced robotic missions to study the habitable

environments of the outer moons in detail—such as

submarines on Europa or balloons on Titan—are

likely after 2020. Over the long term, a human

research presence at some of these worlds may also

become desirable.

11 The Vision for 

Space Exploration
National Aeronautics and

Space Administration 12

Facing page, right: An artist’s drawing of the Terrestrial Planet

Finder. Above: A drawing of humans and advanced robotic assistants building a space telescope. Left: An artist’s concept of the

Spitzer Space Telescope. 
13 The Vision for 

Space Exploration

Extrasolar Planet Research 

and Observatories

“Do there exist many worlds, or is there but a single world? This is one of the most

noble and exalted questions in the study of Nature.”

Albertus Magnus (1193–1280)

“We may object that we have been thinking of the stars as mere bodies . . . but should

rather conceive them as enjoying life and action. On this view the facts cease to

appear surprising.”

Aristotle (384–322 BC)

On the Heavens, Book II, Part 12

Our solar system is composed of nine planets,

including Earth, that circle a central star, the Sun.

Astronomers and philosophers have speculated for

millennia about whether other stars harbor worlds

like Earth and whether these worlds are inhabited.

However, it is only in the last decade that telescopes

have become powerful enough to detect whether

planets of any type circle other stars. In 1995,

astronomers discovered the first solar system besides

our own. Since then, astronomers have found over

100 planets orbiting other stars—and the number

continues to climb with new discoveries.

All of the extrasolar planets discovered to date are

either very large planets or planets that circle very

close to their parent stars. Some extrasolar planets

are many times larger than the largest planet in our

solar system, Jupiter, and orbit even closer to their

parent star than the closest planet to our Sun,

Mercury. Because of the obscuring effects of the

Earth’s atmosphere, the detection and characterization of small planets with normal orbits like Earth is

extremely challenging using ground-based telescopes.

NASA’s Astronomical Search for Origins program

will use a variety of techniques this decade to greatly expand the number and variety of known extrasolar planets. New space telescopes like the Spitzer

and James Webb Space Telescopes, the Kepler mission, and the Space Interferometry mission, will

search newly formed planets circling young stars,

take planetary surveys of thousands of faraway stars,

and detect planets only a few times larger than Earth

around very nearby stars.

The results from these telescopes will be used in 

the design of an advanced space telescope, the

Terrestrial Planet Finder, to be launched during the

next decade. The Terrestrial Planet Finder will be

capable of finding Earth-like planets and detecting

the chemicals in their atmospheres. Just as plants

and animals have changed Earth’s atmosphere over

time, the detection of specific chemicals on other

worlds would indicate that life has evolved on them,

as well.

If the Terrestrial Planet Finder discovers extrasolar

planets with evidence of life, NASA would pursue

additional space telescopes after 2020 that can confirm the existence of life on these worlds and image

their features. Life Finder or Planet Imager telescopes would likely be very large and complex

spacecraft located far from Earth. A human presence

in deep space could be necessary to help erect and

upgrade such future telescopes.
National Aeronautics and

Space Administration 14

Above: Exploration building blocks will provide the capabilities necessary for

exploration of the solar system and beyond.
15 The Vision for 

Space Exploration

Exploration Building Blocks

“As for the future, your task is not to see it, but to enable it.”

Antoine de-Saint Exupery (1900–1944)

The Wisdom of the Sands

“Man hath weaved out a net, and this net throwne upon the Heavens, and now 

they are his own.”

John Donne (1572–1631)

To conduct an effective and exciting program of

exploration and discovery, we must overcome the

limitations of space, time, and energy, as well as various space hazards. Over the next two decades,

NASA plans to develop a number of new capabilities

that are critical to enabling the human and robotic

missions described in this document.

For human explorers to undertake lengthy research

trips on other worlds, they will have to maintain their

health in environments that possess higher radiation

and lower gravity than Earth and that are far from

supplies and medical expertise. Research aboard the

International Space Station and at various laboratories on Earth is critical to understanding the effects

of space environments on the human body, developing techniques for mitigating these hazards, minimizing the logistical burden of supporting humans

far from Earth, and addressing remote medical emergencies. NASA plans to complete assembly of the

Space Station, including international partner elements, by the end of the decade. NASA will also

augment its bioastronautics research program with

the goal that Space Station research necessary to 

support human explorers on other worlds will be

complete by 2016.

The Space Shuttle will be critical to completing

assembly of the Space Station. With Space Station

assembly complete at the end of this decade, NASA

will retire the Space Shuttle and put crew and 

cargo on different launches, a safer approach to crew

transport.

NASA will initiate Project Constellation to develop a

new Crew Exploration Vehicle for future crew transport. This vehicle will be developed in stages, with

the first automated test flight in 2008, more

advanced test flights soon thereafter, and a fully

operational capability no later than 2014. The

design of the Crew Exploration Vehicle will be driven by the needs of the future human exploration 

missions described in this document. The Crew

Exploration Vehicle might also supplement international partner crew transport systems to the Space

Station.

For cargo transport to the Space Station after 2010,

NASA will rely on existing or new commercial

cargo transport systems, as well as international partner cargo transport systems. NASA does not plan to

develop new launch vehicle capabilities except

where critical NASA needs—such as heavy lift—are

not met by commercial or military systems.

Depending on future human mission designs, NASA

could decide to develop or acquire a heavy lift vehicle later this decade. Such a vehicle could be

derived from elements of the Space Shuttle, existing

commercial launch vehicles, or new designs.

In the days of the Apollo program, human exploration systems employed expendable, single-use

vehicles requiring large ground crews and careful

monitoring. For future, sustainable exploration programs, NASA requires cost-effective vehicles that

may be reused, have systems that could be applied 

to more than one destination, and are highly reliable

and need only small ground crews. NASA plans 

to invest in a number of new approaches to exploration, such as robotic networks, modular systems,

pre-positioned propellants, advanced power and

propulsion, and in-space assembly, that could enable

these kinds of vehicles. These technologies will be

demonstrated on the ground, at the Space Station and

other locations in Earth orbit, and on the Moon starting this decade and into the next. Other breakthrough technologies, such as nuclear power and

propulsion, optical communications, and potential

use of space resources, will be demonstrated as part

of robotic exploration missions. The challenges of

designing these systems will accelerate the development of fundamental technologies that are critical

not only to NASA, but also to the Nation’s economic and national security.
National Aeronautics and

Space Administration 16

Above: Mars as seen by the Hubble Space Telescope.
17 The Vision for 

Space Exploration

NASA Transformation

“No one regards what is before his feet; we all gaze at the stars.”

Quintus Ennius (239–169 BC)

To successfully execute the President’s vision,

NASA will refocus its organization, create new

offices where necessary, realign ongoing programs

and personnel, experiment with new ways of doing

business, and tap the great innovative and creative

talents of our Nation.

Prior to this plan, six Enterprises comprised NASA’s

organization—Space Science, Earth Science,

Biological and Physical Research, Aerospace

Technology, Education, and Space Flight. To develop the exploration building blocks described in this

document, NASA has created a new Exploration

Systems Enterprise. Exploration Systems will be

initially responsible for developing the solar system

exploration vehicles and technologies described in

this plan, including the Crew Exploration Vehicle,

nuclear power and propulsion systems, and necessary supporting technologies. Relevant elements of

the Aerospace Technology, Space Science, and

Space Flight enterprises were transferred to the

Exploration Systems Enterprise. The Aerospace

Technology Enterprise was renamed the Aeronautics

Enterprise.

In the past, NASA’s human space flight programs

and robotic exploration programs have largely operated independently of each other. As human explorers prepare to join their robotic counterparts, closer

coordination and integration will be necessary. The

Exploration Systems Enterprise will work closely

with the Space Science Enterprise to use the Moon

as a testing ground for solar system exploration vehicles and technologies.

NASA’s Space Science Enterprise will have responsibility for carrying out robotic testbeds on the Moon

and Mars and will also demonstrate other key technologies for human and robotic exploration in other

missions to Mars and the outer moons. NASA’s

Space Science Enterprise will eventually need to

integrate human capabilities into Mars science planning, and potentially deep space observatory or outer

moon planning.

Many other elements of the NASA organization will

be focused to support this new direction. NASA’s

Biological and Physical Research Enterprise will put

much greater emphasis on bioastronautics research

to enable human exploration of other worlds.

Similarly, Space Station research will be prioritized

to support human exploration.

NASA’s Office of the Space Architect will be

responsible for coordinating and integrating the

exploration activities of NASA’s different

Enterprises and for maintaining exploration

roadmaps and high-level requirements.

As we move outward into the solar system, NASA

will rely more heavily on private sector space capabilities to support activities in Earth orbit and future

exploration activities. In particular, NASA will seek

to use existing or new commercial launch vehicles

for cargo transport to the Space Station, and potentially to the Moon and other destinations.

Building on its long history and extensive and close

ties with the space and research agencies of other

nations, NASA will also actively seek international

partners and work with the space agencies of these

partners in executing future exploration activities.

Many of the technical challenges that NASA will

face in the coming years will require innovative

solutions. In addition to tapping creative thinking

within the NASA organization, NASA will need to

leverage the ideas and expertise resident in the

Nation’s universities and industry. One way that

NASA plans to do this is through a series of

Centennial Challenges. As in the barnstorming days

of early aviation, NASA plans to establish prizes for

specific accomplishments that advance solar system

exploration and other NASA goals.

NASA will also invigorate its workforce, focus its

facilities, and revitalize its field centers. Congress is

reviewing human capital legislation that will provide

NASA with necessary workforce tools. NASA is

also planning to phase out older, underutilized buildings and facilities. As exploration activities get

underway, NASA anticipates additional planning,

reviews, and changes to align and improve its infrastructure.
National Aeronautics and

Space Administration 18

Above: The Moon as seen by the Galileo spacecraft.
19 The Vision for 

Space Exploration

Resources

To confine our attention to terrestrial matters would be to limit the human spirit.

Stephen Hawking (1942– )

The President’s Vision for solar system exploration

is affordable in both the short-term and the longterm. NASA’s budget will increase by five percent

per year over the next three years and at about one

percent for the following two years.

Although the budget increases are modest, NASA

will be able to carry out a robust exploration program. NASA will free up resources in its budget in

three ways: holding down growth in existing programs that do not support the vision; retiring the

Space Shuttle to free up billions of dollars in the next

decade; and focusing on innovations that reduce the

cost of sustained space operations. The chart above

reflects the shift in funding that will occur over time

as the new vision for human and robotic exploration

of the solar system and beyond is implemented.

Exploration Strategy Based on Long-Term Affordability
National Aeronautics and

Space Administration 20
21 The Vision for 

Space Exploration

National Benefits

Just as Meriwether Lewis and William Clark could

not have predicted the settlement of the American

West within a hundred years of the start of their

famous 19th century expedition, the total benefits of

a single exploratory undertaking or discovery cannot

be predicted in advance. Because the very purpose

of exploratory voyages and research is to understand

the unknown, exact benefits defy calculation.

Nonetheless, we can define important categories of

benefits to the Nation and society.

Preparing for exploration and research accelerates

the development of technologies that are important

to the economy and national security. The space

missions in this plan require advanced systems and

capabilities that will accelerate the development of

many critical technologies, including power, computing, nanotechnology, biotechnology, communications, networking, robotics, and materials. These

technologies underpin and advance the U.S. economy and help ensure national security. NASA plans

to work with other government agencies and the private sector to develop space systems that can address

national and commercial needs.

Space exploration holds a special place in the human

imagination. Youth are especially drawn to Mars

rovers, astronauts, and telescopes. If engaged effectively and creatively, space inspires children to seek

careers in math, science, and engineering, careers

that are critical to our future national economic competitiveness.

The accomplishments of U.S. space explorers are

also a particularly potent symbol of American

democracy, a reminder of what the human spirit can

achieve in a free society. However, space exploration also encourages international cooperation,

where spacecraft and explorers come to represent

our world as well as our Nation.

When the unknown becomes known, it catalyzes

change, stimulating human thought, creativity and

imagination. The scientific questions that this plan

pursues have the potential to revolutionize whole

fields of research. For example, scientists are still

working to understand how similarly sized planets,

such as Mars and Earth, could have developed so

differently and what that could mean for our planet.

If life is found beyond Earth, biological processes on

other worlds may be very different from those

evolved on our world. Outside the sciences, the very

knowledge that life exists elsewhere in the universe

may hold revelations for fields in the humanities.

Exploration and discovery are key agents of growth

in society—technologically, economically, socially,

internationally, and intellectually. This plan sets 

in motion activities that will contribute to change

and growth in the U.S. and the world over the next

century.

NASA research stimulates and inspires young minds and

provides critical technologies for the Nation.

“Mankind is drawn to the heavens for the same reason we were once drawn into

unknown lands and across the open sea. We choose to explore space because doing

so improves our lives, and lifts our national spirit.”

President George W. Bush

January 14, 2004
National Aeronautics and

Space Administration 22

Above: An artist’s drawing of a human exploration base on Callisto, Jupiter’s

second largest moon.

Image Credits

Page vi An artist’s concept of a spacecraft, equipped with a centrifuge and nuclear–electric propulsion, traveling to

Mars, John Frassanito and Associates.

Page 6 An artist’s concept of lunar exploration, John Frassanito and Associates.

Page 8 A drawing of astronauts and robots exploring Mars, John Frassanito and Associates.

Page 12 A drawing of astronauts and advanced robotic assistants building a space telescope, Pat Rawlings, SAIC.

Below Analytical Mechanics Associates.

Editing, layout, and design by The Tauri Group, LLC, and Eileen Schramm visual communication.
Above: Spiral galaxy M81, located

approximately 12 million light-years from

Earth, as seen by the Spitzer Space

Telescope.
National Aeronautics and

Space Administration

NASA Headquarters

Washington, DC 20546

NP-2004-01-334-HQ

http://www.nasa.gov