To
energize a discussion of long-range goals and strategies for the civilian
space program, four bold initiatives were selected for definition, study,
and evaluation:
1. Mission to Planet Earth: a program that would use the perspective afforded from space to study and characterize our home planet on a global scale.
2. Exploration of the Solar System: a program to retain U.S. leadership in exploration of the outer solar system, and regain U.S. leadership in exploration of comets, asteroids, and Mars.
3. Outpost
on the Moon: a program that would build on and extend the legacy of the
Apollo Program, returning Americans to the Moon to continue exploration, to
establish a permanent scientific outpost, and to begin prospecting the Moon's
resources.
4. Humans
to Mars: a program to send astronauts on a series of round trips to land
on the surface of Mars, leading to the eventual establishment of a permanent
base.
The
intent is not to choose one initiative and discard the other three, but rather
to use the four candidate initiatives as a basis for discussion. For this
reason, it was important to choose a set of initiatives which spanned a broad
spectrum of content and complexity.
The
ground rules for this study are important to understand, since they influenced
the detailed definition of the initiatives. The ground rules, set forward
at the outset of this study, were:
The candidate initiatives were developed and presented to NASA management to: (1) evaluate the initiatives and their implications, and (2) promote a discussion of the attributes of each initiative to determine the elements which are most important to NASA and to the United States.
Each initiative was developed by a separate task group, which discussed the goals, milestones, and elements of the initiative, and then determined the requisite transportation, space facilities, and technologies. For each initiative, an “advocate” was identified to work with appropriate NASA personnel to develop programmatic details. These four advocates presented the strategies, scenarios, requirements, and rationale to senior NASA management.
Two
initiatives, Mission to Planet Earth and Exploration of the Solar System,
had a body of recent work from which to draw. The 1986 report of the Earth
System Sciences Committee of the NASA Advisory Council, Earth System Science:
A Program for Global Change, clearly states goals for the future observation
of Earth. Two reports by the Solar System Exploration Committee of the NASA
Advisory Council similarly articulate goals and recommendations for solar
system exploration. Titled Planetary Exploration through Year 2000: Part
One: A Core Program, and Part Two: An Augmented Program, these reports
outline both a conservative, steady program for solar system exploration and
a set of more challenging, exciting missions to be undertaken if resources
to do so become available. The other two initiatives, Outpost on the Moon
and Humans to Mars, did not have clearly delineated strategies available and
no specific organization within NASA was dedicated to their advocacy.
(MISSING PICTURE)
An Earth-orbiting polar platform.
Mission
to Planet Earth is an initiative to understand our home planet, how forces
shape and affect its environment, how that environment is changing, and how
those changes will affect us. The goal of this initiative is to obtain a comprehensive
scientific understanding of the entire Earth System, by describing how its
various components function, how they interact, and how they may be expected
to evolve on all time scales.
The
challenge is to develop a fundamental understanding of the Earth System, and
of the consequences of changes to that system, in order to eventually develop
the capability to predict changes that might occur—either naturally, or as
a result of human activity.
Background
With
the launch of the first experimental satellites in the 1960s, NASA pioneered
the remote sensing of Earth from space. Over the past two decades, the scientific
community has concluded that Earth is in a process of global change, and scientists
now believe that it is necessary to study Earth as a synergistic system. As
stated in the Earth System Sciences Committee report cited earlier, “Global
observations, new space technology, and quantitative models have now given
us the capability to probe the complex, interactive processes of Earth evolution
and global change.” Interactive physical, chemical, and biological processes
connect the oceans., continents, atmosphere, and biosphere of Earth in a complex
way. Oceans, ice-covered regions, and the atmosphere are closely linked and
shape Earth’s climate; volcanism links inner Earth with the atmosphere; and
biological activity significantly contributes to the cycling of chemicals
(e. g., carbon, oxygen, and carbon dioxide) important to life. And now it
is clear that human activity also has a major impact on the evolution of the
Earth System.
Global-scale
changes of uncertain impact, ranging from an increase in the atmospheric warming
gases, carbon dioxide and methane, to a hole in the ozone layer over the Antarctic,
to important variations in vegetation covers and in coastlines, have already
been observed with existing measurement capabilities. The potentially major
consequences, either detrimental or beneficial, suggest an urgent need to
understand these variations.
We
currently lack the ability to foresee changes in the Earth System, and their
subsequent effects on the planet's physical, economic, and social climate.
But that could change; this initiative would revolutionize our ability to
characterize our home planet, and would be the first step toward developing
predictive models of the global environment.
Strategy
and Scenario
The
guiding principle behind this initiative is to adopt an integrated approach
to observing Earth. The observations from various sensors on platforms and
satellites will be coordinated to perform global surveys and also to perform
detailed observations of specific phenomena.
Mission
to Planet Earth proposes:
1. To establish and maintain a global observational system in space, which would include experiments and free-flying platforms, in polar, low-inclination, and geostationary orbits, and which would perform integrated, long‑term measurements.
2. To use the data from these satellites along with in-situ information
and numerical modeling to document, understand, and eventually predict global
change.
As
illustrated in Figure 5, the global observational system would include
a suite of nine orbiting platforms:
(MISSING PICTURE)
Figure 5. Mission to Planet Earth
Low-inclination,
low-altitude payloads would also be included in the system. The Earth Radiation
Budget Experiment satellite, launched from the Space Shuttle in 1984, and
the synthetic aperture radar sensors, SIR-A and SIR-B, flown on the Shuttle
in 1981 and 1984, are the types of experiments that would fall into this category.
Another example would be a proposed Space Station-attached payload designed
to obtain coverage of tropical rainfall with sampling at all local times.
The
integrated system would measure, the full complement of the planet’s characteristics,
including: global cloud cover, vegetation cover, and ice cover; global rainfall
and moisture; ocean chlorophyll content and ocean topography; motions and
deformations of Earth's tectonic plates; and atmospheric concentration of
gases such as carbon dioxide, methane, and ozone.
Space-based
observations would also be coordinated with ground-based experiments and the
data from all observations would be integrated by an essential component of
this initiative: a versatile, state-of-the-art information management system.
This tool is critical to data analysis and numerical modeling, and would enable
the integration of all observational data and the development of diagnostic
and predictive Earth System models.
This
global observational system would be designed to operate for decades, serviced
either by astronauts or robotic systems to ensure long life and to provide
the continuing data collection, integration, and analysis required by this
initiative.
Because
of its international and interdisciplinary nature, the Mission to Planet Earth
requires the strong support and involvement of other U.S. government agencies
(particularly the National Science Foundation and the National Oceanic and
Atmospheric Administration) and of our international partners. The roles of
the various Federal agencies have been examined in detail by the Earth System
Sciences Committee. NASA’s responsibilities would include the information
management system and platforms and experiments described previously. Most
important, NASA would also provide the supporting technology, space transportation,
space support services, and much of the scientific leadership.
Technology,
Transportation, and Orbital Facilities
This
initiative requires advances in technology to enhance observations, to handle
and deliver the enormous quantities of data, and to ensure a long operating
life. Sophisticated sensors and information systems must be designed and developed,
and advances must be made in automation and robotics (whether platform servicing
is performed by astronauts or robotic systems).
To
achieve its full scope, this initiative requires the operational support of
Earth-to-orbit and space transportation systems to accommodate the launching
of polar and geostationary platforms. This does not represent a large number
of additional launches, but it does require the capability to launch large
payloads to polar orbit; Titan IVs would be used to accomplish this. Since
the envisioned geostationary platforms would be lifted to low-Earth orbit,
assembled at the Space Station, and then lifted to geosynchronous orbit with
a space transfer vehicle well-developed orbital facilities are essential.
By the late 1990s, the Space Station must be able to support on-orbit assembly,
and a space transfer vehicle must exist.
SUMMARY
NASA,
with its technical and scientific expertise, is uniquely suited to lead Mission
to Planet Earth. Only from Earth orbit can we gain the perspective necessary
to observe the Earth System and the interaction of its components on a global
scale. We now understand what to observe, and how to observe it. While we
do not yet know how the data will piece together, the resulting Earth System
models, developed and refined over years of study, are the important products
of this initiative, and would establish NASA as a responsive agency ready
to meet the challenge of a genuine time-critical need. Championing this initiative
would establish the United States at the forefront of a world recognized need
to understand our changing planet.
(MISSING PICTURE)
The Comet Rendezvous Asteroid
Flyby spacecraft
flies in formation with Comet
Tempel 2.
EXPLORATION
OF THE SOLAR SYSTEM
This
initiative would build on NASA's longstanding tradition of solar system exploration
and would continue the quest to understand our planetary system, its origin,
and its evolution. Solar system bodies are divided into three distinct classes:
the primitive bodies (comets and asteroids), the outer (gas giant) planets,
and the inner (terrestrial) planets. Each class occupies a unique position
in the history of the solar system, and each is the target of a major mission,
in this initiative, which includes a comet rendezvous (the Comet Rendezvous
Asteroid Flyby mission), a mission to Saturn (Cassini), and three
sample return missions to Mars. The centerpiece of the initiative is the robotic
exploration of Mars; the first of these three automated missions would bring
a handful of Mars back to Earth before the year 2000.
Background
In
the 1960s and 1970s, exploration of the solar system was an important and
visible component of the U.S. space program. Highly successful missions such
as Pioneer, Viking, and Voyager made the United States the unchallenged leader
in the exploration of the planets. Our spacecraft were consistently both the
first and the best. While the Soviet Union concentrated most of its efforts
on the exploration of Venus, the rest of the solar system was left to the
United States.
But
now almost a decade has elapsed between U.S. planetary missions—the last was
Pioneer Venus, launched in 1978. Galileo (to Jupiter), Magellan
(to Venus), and the Mars Observer are in line for launch between 1989
and 1992, but no other planetary missions have been approved. Although the
successful Voyager missions to the outer planets clearly established
U.S. leadership in exploration of the outer solar system, plans for the future
beyond the Galileo mission are uncertain.
Other nations have recently begun to undertake innovative and challenging programs (the recent international flotilla to Halley's Comet is an excellent example). The Soviets have announced an ambitious program for the exploration of Mars which will culminate in a sample return mission, and the Europeans have set a long-term goal of returning a sample from a comet. Although currently scheduled U.S. missions will ensure that the United States will remain a leader in certain areas of solar system exploration through 1995, the position of the United States beyond 1995 is in question. This initiative would maintain U.S. leadership in exploration of the outer planets, and would regain and sustain U.S. leadership in the exploration of both the planet Mars and the primitive bodies of the solar system.
Strategy
and Scenario
This
initiative is based on the balanced strategy developed by the Solar System
Exploration Committee of the NASA Advisory Council and elucidated in its two
reports (cited previously) describing a Core Program and an Augmented Program
for planetary exploration. The missions include:
1.
The
Comet Rendezvous Asteroid Flyby (CRAF) mission would investigate
the beginnings of our solar system, studying a Main Belt asteroid and a comet,
which represent the best preserved samples of the early solar system. Because
of their primordial nature, comets can provide critical clues about the processes
that led to the origin and evolution of our solar system.
The CRAF mission scenario is shown in Figure
6. After a 1993 launch and a six-month cruise, the spacecraft would fly
past the asteroid Hestia at an altitude of about 10,000 kilometers. CRAF’s
visual and infrared asteroid imaging systems would conduct investigations
of Hestia’s surface composition and structure. CRAF would then continue
its journey for a rendezvous with a periodic comet, Tempel 2. The spacecraft
would maneuver to within 25 kilometers of the comet's nucleus and begin a
series of observations, which includes shooting two penetrators into the nucleus
itself for detailed in-situ measurements. The spacecraft would fly
in close formation with the comet until it nears the Sun and becomes active;
then the spacecraft would maneuver farther away to observe the comet's coma
and tail.
2.
The
Cassini mission would explore Saturn and its largest moon, Titan. The
giant outer planets offer us an opportunity to address key questions about
their internal structures and compositions through detailed studies of their
atmospheres. Titan is an especially interesting target for exploration because
the organic chemistry now taking place there provides the only planetary-scale
laboratory for studying processes that may have been important in the prebiotic
terrestrial atmosphere.
(MISSING PCITURES)
Figure 6. The Comet Rendezvous Asteroid
Flyby Mission
Figure 7. The Cassini Mission
The Cassini mission proposed in this initiative would be a considerably expanded version of the Cassini mission considered by the Solar System Exploration Committee. (Figure 7 shows the scenario for the baseline version of Cassini.) This expanded mission would be launched in 1998 for the long interplanetary voyage to arrive at Saturn in 2005 with a full array of investigative instruments. An orbital spacecraft and three probes would conduct a comprehensive three-year study of the planet and its rings, satellites, and magnetosphere. One atmospheric probe would be launched toward Titan. The expanded Cassini mission would also carry one probe to investigate the Saturnian atmosphere, and one semi-soft lander which would reach the surface of Titan.
3. The Mars Rover/Sample Return missions would, in journeys covering hundreds of millions of miles, gather samples of Mars and bring them back to Earth. Because of its relevance to understanding Earth and other terrestrial planets, and because it is the only other potentially habitable planet in our solar system, Mars is an intriguing target for exploration. The Mars Rover/Sample Return mission scenario is shown in Figure 8. It would involve a soft landing on the Martian surface, deployment of a "smart" surface rover to select and collect samples delivery of the samples to an ascent vehicle, and transfer of the samples from Mars orbit to a return vehicle. The samples would then most likely be returned to a sample handling module on the Space Station for analysis. The initiative would include three such missions: two launched in 1996, probably sending redundant rovers and ascent vehicles to ensure return of a sample in 1999, and one launched in 1998/99 with return in 2001.
(MISSING PICTURE)
Figure 8. The Mars Rover/Sample Return
Mission
Technology,
Transportation, and Orbital Facilities
As
it is defined, this initiative places a premium on advanced technology and
enhanced launch capabilities to maximize the scientific return. It requires
aerobraking technology for aerocapture and aeromaneuvering at Mars, and a
high level of sophistication in automation, robotics, and sampling techniques.
Advanced sampling methods are necessary to ensure that geologically and chemically
varied and interesting samples are collected for analysis.
The
Solar System Exploration initiative significantly benefits from improved launch
capability in terms of the science returned from both the Mars and the Cassini
missions. In fact, it is a heavy-lift launch vehicle that enables the full
complement of three different probes to be carried in the expanded Cassini
mission.
The
Space Shuttle is not required for any of the missions in the initiative. The
Space Station would not be needed until 1999, when an isolation module may
be used to receive the Martian samples.
Summary
This
initiative adopts the broad strategy devised by the Solar System Exploration
Committee for a balanced, systematic program of solar system exploration.
Spacecraft would be sent to a comet (Tempel 2), an outer planet (Saturn),
and an inner planet (Mars), to study representatives of each of-the three
distinct classes of solar system bodies in exquisite detail. The U.S. would
take a bold step forward in the exploration of Mars and we would continue
our leadership in exploration of the outer solar system. The scientific return
over the next two decades would complement the outstanding solar system exploration
program of the 1960s and 1970s and would offer additional insights into the
evolution of our Earth and the solar system.
(MISSING PICTURE)
This
initiative builds on the legacy of Apollo and envisions a new phase
of lunar exploration and development—a phase leading to a human outpost on
another world. That outpost would support scientific research and exploration
of the Moon's resource potential, and would represent a significant extraterrestrial
step toward learning to live and work in the hostile environments of other
worlds.
Beginning
with robotic exploration in the 1990s, this initiative would land astronauts
on the lunar surface in the year 2000, to construct an outpost that would
evolve in size and capability and would be a vital, visible extension of our
capabilities and our vision.
Background
The
Apollo Program was a great national adventure. We sent explorers to scout
the cratered highlands and smooth maria of the Moon, and to bring samples
collected on their trips back to laboratories on Earth. The world was fascinated
by the Apollo missions and the information they obtained, and the samples
provided scientists many exciting clues about the Moon's origin and chemical
composition.
The
Apollo era ended 15 years ago, before we could fully explore the promise
of lunar science and lunar resources. But we learned that human beings can
work on the surface of the Moon, and we laid the technical foundation to develop
the scientific and engineering tasks for the next stages of exploration. This
initiative would send the next generation of pioneers—to pitch their tents,
establish supply lines, and gradually build a scientifically and technically
productive outpost suitable for long-term habitation.
This initiative represents a sustained commitment to learn to live and work in space. As our experience and capabilities on the lunar surface grow, this extraterrestrial outpost will gradually become less and less dependent on the supply line to Earth. The first steps toward “living off the lunar land” will be learning to extract oxygen from the lunar soil, where it is plentiful, and learning to make construction materials. The lunar soil would eventually be a source of oxygen for propellant and life-support systems, and a source of material for shelters and facilities.
The Moon’s unique environment provides the opportunity for significant scientific advances; the prospect for gains in lunar and planetary science is abundantly clear. Additionally, since the Moon is seismically stable and has no atmosphere, and since its far side is shielded from the radio noise from Earth, it is a very attractive spot for experiments and observations in astrophysics, gravity wave physics, and neutrino physics, to name a few. It is also an excellent location for materials science and life science research because of its low gravitational field (one-sixth of Earth’s).
Strategy
and Scenario
This
initiative proposes the gradual, three-phase evolution of our ability to live
and work on the lunar surface.
Phase
I: Search for a Site (1990s)
The
initial phase would focus on robotic exploration of the Moon. It would begin
with the launching of the Lunar Geoscience Observer, which will map the surface,
perform geochemical studies, and search for water at the poles. Depending
on the discoveries of the Observer, robotic landers and rovers may be sent
to the surface to obtain more information. Mapping and remote sensing would
characterize the lunar surface and identify appropriate sites for the outpost.
The discovery of water or other volatiles would be extremely significant,
and would have important implications for the location of a habitable outpost.
Phase
II: Return to the Moon (2000-2005)
Phase
II begins with the return of astronauts to the lunar surface. (The scenario
is sketched in Figure 9.) The initiative proposes that a crew be transported
from the Space Station to lunar orbit in a module propelled by a lunar transfer
vehicle. The crew and equipment would land in vehicles derived from the transfer
vehicle. Crew members would stay on the surface for one to two weeks, setting
up scientific instruments, a lunar oxygen pilot plant, and the modules and
equipment necessary to begin building a habitable outpost. The crew would
return to the orbiting transfer vehicle for transportation back to the Space
Station.
Over the first few flights, the early outpost would grow to include a habitation area, a research facility, a rover, some small machinery to move lunar soil, and a pilot plant to demonstrate the extraction of lunar oxygen. By 2001, a crew could stay the entire lunar night (14 Earth days), and by 2005.the outpost would support five people for several weeks at a time.
Phase
III: At Home on the Moon (2005-2010)
Phase
III evolves directly from Phase II, as scientific and technological capabilities
allow the outpost to expand to a permanently occupied base. The base would
have closed-loop life-support systems and an operational lunar oxygen plant,
and would be involved in frontline scientific research and technology development.
The program also requires the mobilization of disciplines not previously required
in the space program: surface construction and transportation, mining, and
materials processing.
(MISSING PICTURE)
Figure 9. Return to the Lunar Surface:
Piloted Sortie, Expendable
Lander
By
2010, up to 30 people would be productively living and working on the lunar
surface for months at a time. Lunar oxygen will be available for use at the
outpost and possibly for propellant for further exploration.
Technology,
Transportation, and Orbital Facilities
This
initiative envisions frequent trips to the Moon after the year 2000—trips
that would require a significant investment in technology and in transportation
and orbital facilities in the early 1990s.
The
critical technologies for this initiative are those which would make human
presence on the Moon meaningful and productive. They include life-support
system technologies to create a habitable outpost; automation and expert systems
and surface power technologies to make the outpost functional and its inhabitants
productive; and lunar mining and processing technologies to enable the prospecting
for lunar resources.
The
transportation system must be capable of regularly transporting the elements
of the lunar outpost, the fuel for the voyage, and the lunar crew to low-Earth
orbit. This requires a heavy-lift launch vehicle and a healthy Space Shuttle
fleet. The transfer of both cargo and crew from the Space Station to lunar
orbit requires the development of a reusable space transfer vehicle. This
and a heavy-lift launch vehicle will be the workhorses of the Lunar initiative.
The
Space Station is an essential part of this initiative. As the lunar outpost
evolves, the Space Station would become its operational hub in low-Earth orbit.
Supplies, equipment, and propellants would be marshalled at the Station for
transit to the Moon. It is therefore required that the Space Station evolve
to include spaceport facilities.
In
the 1990s, the Phase I Space Station would be used as a technology and systems
test bed for developing closed-loop life-support systems, automation and robotics,
and the expert systems required for the lunar outpost. The outpost would,
in fact, rely on the Space Station for many of its systems and subsystems,
including lunar habitation modules which would be derivatives of the Space
Station habitation/ laboratory modules.
Summary
This
initiative represents a conceptual leap outward from Earth. The challenge
is to tame and harness the space frontier—to go beyond Apollo, and
explore the Moon for what it can tell us, and what it can offer us, as a research
and development; center and as a resource in itself. Exploring, prospecting,
and settling are parts of our heritage and will most assuredly be parts of
our future.
(MISSING PICTURE)
This
bold initiative is committed to the human exploration, and eventual habitation,
of Mars. Robotic exploration of the planet would be the first phase and would
include the return of samples of Martian rocks and soil. Early in the 21st
Century, Americans would land on the surface of Mars; within a decade of these
first piloted landings, this initiative would advance human presence to an
outpost on Mars.
Background
The
Red Planet has piqued our curiosity and stimulated our imaginations for decades.
Our previous exploration of Mars has revealed a fascinating world of enormous
mountains and deep canyons, and a surface etched by erosion during ancient
floods. Mars may once have supported life; in any case, it is the only potentially
habitable planet in our solar system besides Earth.
America
has led the way in humanity's exploration of the worlds beyond our own planet.
We have sent spacecraft to the outer reaches of the solar system, and our
emissaries have walked on the surface of the Moon. The Humans to Mars initiative
would greatly increase our understanding of the solar system, and would push
the frontier of human presence ever further beyond the confines of Earth.
The
United States has also led the way in the robotic exploration of Mars. The
last visitor to that planet was the extremely successful Viking spacecraft,
which landed on the Martian surface in 1976, and transmitted data to Earth
until late in 1982. During the coming decade, humanity will learn more about
Mars, but it will largely be the result of ambitious Soviet, not American,
programs. Our single mission to Mars, the Mars Observer, to be launched in
1992, is a small spacecraft which will perform an important geochemical characterization
of Mars while in orbit around the planet. Meanwhile, the Soviets have announced
three separate missions to Mars before 1995, and the possibility of a sample
return mission in the late 1990s.
This
leadership initiative declares America’s intention to continue exploring Mars,
and to do so not only with spacecraft and rovers, but also with humans. It
would clearly rekindle the national pride and prestige enjoyed by the U.S.
during the Apollo era. Humans to Mars would be a great national adventure;
as such, it would require a concentrated massive national commitment—a commitment
to a goal and its supporting science, technology, and infrastructure for many
decades.
Strategy
and Scenario
This
initiative would:
1. Carry out comprehensive robotic exploration of Mars in the 1990s. The robotic missions would begin with the Mars Observer, include an additional Observer mission, and culminate in a pair of Mars Rover/Sample Return missions. These missions would perform geochemical characterization of the planet, and complete global mapping and support landing site selection and certification.
2. Establish an aggressive Space
Station life sciences research program to validate the feasibility of long-duration
spaceflight. This program would develop an understanding of the physiological
effects of long-duration flights, of measures to counteract those effects,
and of medical techniques and equipment for use on such flights. An important
result would be the determination of whether eventual Mars transport vehicles
must provide artificial gravity.
3. Design, prepare for, and perform three fast piloted round-trip missions to Mars. These flights would enable the commitment, by 2010, to an outpost on Mars.
The Mars missions described in this initiative are one-year, round-trip “sprints,” with astronauts exploring the Martian surface for two weeks before returning to Earth. The chosen scenario significantly reduces the amount of mass which must be launched into low-Earth orbit, and by doing so brings a one-year round trip into the realm of feasibility. This is accomplished by splitting the mission into two separate parts—a cargo vehicle and a personnel transport—and judiciously choosing the launch date for each.
The
Mars cargo vehicle minimizes its propellant requirements by taking a slow,
low-energy trip to Mars. The vehicle would be assembled in low-Earth orbit
and launched for Mars well ahead of the personnel transport, and would carry
everything to be delivered to the surface of Mars plus the fuel required for
the crew's trip back to Earth (Figure 10).
The
personnel transport would be assembled and fueled in low-Earth orbit, and
would leave for Mars only after the cargo vehicle had arrived in Mars orbit.
It would carry a crew of six astronauts, crew support equipment, and propellant
for the outbound portion of the trip (Figure 11). Once in Mars orbit,
it would rendezvous with the cargo vehicle, refuel, and prepare for descent
to the surface. The landing party would spend 10 to 20 days on the Martian
surface, and then rerendezvous with the personnel transport for the trip back
to Earth orbit (Figure 12). Recovery in Earth orbit would return the
crew to a Space Station rehabilitation facility (Figure 13). The round-trip
time for this scenario is approximately one year.
(MISSING PICTURES)
Figure 10. Piloted Mars Sprint Scenario—Split
Mission Option:
Earth-Orbital Cargo Flight
Operations
Figure 11. Piloted Mars Sprint Scenario—Split
Mission Option:
Earth-Orbital Cargo Flight
Operations
The initiative proposes three of these sprint missions, the third around the year 2010. By the second decade of the 21st Century, the U.S. would have the knowledge, the experience, and the technology base to begin developing an outpost on Mars.
Technology,
Transportation, and Orbital Facilities
A
significant, long-term commitment to developing several critical technologies
and to establishing the substantial transportation capabilities and orbital
facilities is essential to the success of the Mars initiative. The Mars expeditions
require the development of a number of technologies, including aerobraking
(which significantly reduces the amount of mass which must be lifted to low-Earth
orbit), efficient interplanetary propulsion, automation and robotics, storage
and transfer of cryogenics in space, fault-tolerant systems, and advanced
medical technology. Technology development must be initiated immediately to
support the timetable of this scenario.
Even
with separate cargo and personnel vehicles, and technological advances such
as aerobraking, each of these sprint missions requires that approximately
2.5 million pounds be lifted to low-Earth orbit. (In comparison, the Phase
1 Space Station is projected to weigh approximately 0.5 million pounds.) It
is clear that a robust, efficient transportation system, including a heavy-lift
launch vehicle, is required. The complement of launch vehicles must be able
to lift the cargo and personnel required by the sprint missions to the Space
Station in a reasonable period of time. Like the outpost on the Moon, this
initiative requires a substantial investment in launch systems, for transport
of both cargo and crew.
(MISSING PICTURE)
Figure 12. Piloted Mars Sprint Scenario—Split
Mission Option:
Mars-Orbital/Surface Operations
The
Phase 1 Space Station is a crucial part of this initiative. In the 1990s,
it must support the critical life sciences research and medical technique
development. It will also be the technology test bed for life-support systems,
automation and robotics, and expert systems.
Furthermore,
we must develop facilities in low-Earth orbit to store large quantities of
propellant, and to assemble large vehicles. The Space Station would have to
evolve in a way that would meet these needs.
Summary
This
initiative would send representatives of our planet to Mars during the first
decade of the 21st Century. These emissaries would begin a phase of human
exploration and reconnaissance that would eventually lead to the establishment
of a permanent human presence on another world.
A
successful Mars initiative would recapture the high ground of world space
leadership and would provide an exciting focus for creativity, motivation,
and pride of the American people. The challenge is compelling, and it is enormous.
(MISSING PICTURES)
Figure 13. Piloted Mars Sprint Scenario—Split
Mission Option:
Earth Recovery Operations