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SPACE STATION FREEDOM: Goddard Space Flight Center

The Goddard Space Flight Center was established in 1959 at
Greenbelt, Maryland.  It was NASA's first major scientific
laboratory devoted entirely to the exploration of space.
Named after Dr. robert Hutchings Goddard, the man recognized
as the "Father of American Rocketry," the center continues
its commitment to scientific research and development for
space exploration.  Goddard has one of the world's leading
groups of scientists, engineers and administrative managers
devoted to research in space, Earth sciences and
applications.  It employs more scientists than any other
NASA center.  It also is the only national laboratory that
can develop, design, fabricate, test, launch and analyze
space science missions using all its own resources.

Today, Goddard scientists, engineers and technicians are
working on advanced missions to support both terrestrial and
astronomical research.  The spacecraft they build and the
scientific research they conduct are expanding our knowledge
of the Earth, the solar system, and the universe.  Goddard
plays an important role in many of our nation's most
challenging space missions.  Goddard manages the worldwide
tracking and communications network that support these
missions.  The network currently consists of ten ground
stations, the Network Control Center, and the Tracking and
Data Relay Satellite System (TDRSS).  This network will also
support Space Station Freedom.

The Goddard Space Flight Center has supported all of this
country's major space programs including the manned programs
such as: Mercury, Gemini, Apollo, Skylab and Shuttle and
many unmanned programs such as TIROS, NIMBUS, LANDSAT, the
Orbiting Astronomical Observatory, the International
Ultraviolet Explorer and many others.  Goddard also manages
the Delta launch vehicle program.  Goddard continues to
support new space missions in their areas of expertise such
as the Hubble Space Telescope (HST), the Cosmic Background
Explorer (COBE) and various space platforms planned for the
1990's such as the Gamma Ray Observatory (GRO), and Upper
Atomspheric Research Satellite (UARS).

The fundamental mission of the Goddard Space Flight Center
is the expansion of knowledge of the Earth, its environment,
the solar system, and the universe through the conduct of
scientific research and the management, development, and use
of near-Earth  space systems.  Goddard is a collection of
specialized laboratories committed to excellence in
challenging areas of research and development to ensure that
the Nation and NASA maintain leadership in space science and
technology.  Goddard has diverse skills in science,
engineering, operations, and management disciplines to
provide the capability for integrating internal and external
resources in effective mission management and implementation
of NASA programs.  Goddard's science role is to provide
NASA's principal leadership and competence in space an Earth
sciences; advancing scientific understanding, disseminating
knowledge, and ensuring quality guidance and support to
NASA's space research, technology, and flight programs.

Goddard's engineering role is to excel in research,
engineering, development, and application of technology for
sensors, instruments, spacecraft, and complete information
systems for space flight and ground system use.

Goddard serves as the NASA focal point for the planning and
execution of near-Earth spaceflight projects for science and
applications research.  Goddard manages these projects in
the most productive manner possible, achieving maximum
returns on the resources invested.  Goddard also provides a
launch range and research airport at the Wallops Flight
Facility on Virginia's eastern shore for suborbital rocket,
balloon, and aeronautical missions.  Goddard is a team of
some 3,700 civil service employees and 8,100 contractors;
about 12,000 people working for the expansion of knowledge
of the Earth.


Goddard/Space Station Freedom Unique Activities

Flight Telerobotic Servicer (FTS)

Goddard is responsible for development and implementation of
the FTS, including the selection of appropriate technology,
conducting Shuttle demonstration flights, delivering the
flight element and providing a ground based training and
evaluation capability.  Goddard works with other NASA
centers conducting research in automation and robotics and
evolutionary growth.

Attached Payload Accommodations

Goddard is responsible for accommodating various scientific,
commercial and technology development instruments and
experiments, providing utilities such as power, thermal
control, data system interfaces, pointing and stability;
providing attachment fixtures and other equipment necessary
to properly place and operate the payloads and provide
attitude determination.


Unmanned Free Flying Platforms

Goddard is responsible for managing the detailed design,
development, test, and evaluation of the U.S. platforms that
are not attached to the station but fly freely in their own
orbits.  The initial U.S. polar platform will support the
Earth Observing System (EOS) mission. Another U.S. platform,
co-orbiting with the space station in the late 1990's, will
serve additional scientific users from various disciplines.


Assembly, Maintenance and Servicing

Goddard is responsible for developing the servicing system
architecture for all flight vehicles and attached payloads
to optimize station performance for user operations.
Goddard works with the user community to determine
requirements that impact design and evaluates capabilities
such as replacement, replenishment, retrieval, storage,
assembly, test and verification of intended operation.




Space Station Freedom Unique Activities

Flight Telerobotic Servicer Program
The Flight Telerobotic Servicer (FTS) is the result of
discussions between NASA and the Congress on how the Space
Station Freedom program could best be utilized to enhance
the technologies of robotics and machine intelligence.
Mandated by Congress in the conference report accompanying
NASA's FY 1986 appropriations bill, the FTS is an outgrowth
of the Automation and Robotics (A&R) initiative of  the
project's Definition and Preliminary Design Phase ("Phase
B").


The FTS is a telerobotic device capable of precise
manipulations in space.  It will operate with a mix of
direct teleoperation and supervisory control by astronauts.
It will be used to assist in  assembly and servicing
operations.  The FTS  will improve the  efficiency and
safety of  operations.  Initially intended for relatively
simple tasks, the FTS capabilities will evolve over time to
accommodate increasingly sophisticated operations.
Invaluable not only for station operations, the FTS will
have wide application in orbits beyond the reach of the
present manned space transportation system.

The Goddard Space Flight Center's Space Station Freedom
Projects organizaton is accountable for the development and
implementation of the FTS.  Technical and management
activities at GSFC are continuing to focus and drive the
implementation of the FTS program in response to the A&R
objectives of the Space Station Freedom program.  Other NASA
Centers support Goddard in implementing the FTS program.

Early in space station planning, NASA initiated a study to
determine the most effective manner of applying A&R
technologies both to enhance Freedom and to provide the
desired development impetus.  The NASA Advanced Technology
Advisory Committee (ATAC), established by NASA at the
direction of Congress, evaluated the recommendations of
universities, aerospace and automation related industries
and government laboratories, integrating them into a
comprehensive set of recommendations for further study by
Phase B contractors. These recommendations may be summarized
as follows:


---Automation and robotics should be a significant element
of the Space Station Freedom program.
---Initially,  the station should be designed to accommodate
evolution and growth in automation and robotics.

---Initially, the station should utilize significant
elements of automation and robotics technology.

---Criteria for the incorporation of A&R technology should
be developed and promulgated.

---Verification of the performance of automated equipment
should be stressed, including terrestrial and space
demonstrations to validate technology for
##station use.

---Maximum use should be made of technology developed for
industry and government.

---The techniques of automation should be used to enhance
NASA's management capability.

---NASA should provide the measures and assessments to
verify the inclusion of automation and robotics in the space
station program.


During the course of  Phase B Study, the ATAC continued to
monitor the implementation of these recommendations.  As a
result of the efforts to date, functions which would benefit
from application of robotic technologies have been
identified and robotic concepts have been evaluated.

Space Station Freedom Unique Activities

The FTS program will be implemented by establishing and
coordinating four major elements:

---A Technology element to select, modify, and transfer
evolving technology and to identify requirements for new
technology.
---A Flight Demonstration element to conduct demonstration
flight(s) on the NSTS prior to station assembly for
verification of design and operations concepts.
---A Freedom Flight System element to deliver, operate, and
evolve an FTS for
##use by the Space Station Freedom program.
---A Ground System element to provide continuing capability
to evaluate and implement advanced robotic technology and to
assist training operations and FTS on-orbit performance
evaluation.

As can be seen from the figure at the right, many other
NASA, government and industry organizations are
participating in the FTS program, each contributing in their
areas of Center or organizational expertise.

The FTS program will provide an early demonstration of the
FTS capabilities onboard the Shuttle sometime in 1991.  The
results of that demonstration and research being conducted
on the ground at the NASA Centers and contractors will be
transferred into the actual flight article that will be used
to assemble  Space Station Freedom beginning in 1995.  The
role of the FTS will evolve with Space Station Freedom over
time, taking on different tasks and roles consistent with
the assembly, servicing, maintenance and operations
activities.


GODDARD   SPACE   FLIGHT   CENTER


Elements and Systems

Attached Payload Accommodations
Goddard is responsible for accommodating many and various
scientific, commercial, and technology development
instruments and experiments.  The term "payload" is used to
mean the total complement of specific instruments, space
equipment, support hardware, software, and consumables
required to accomplish a discrete activity in space.  A
payload, then, may be large or small, simple or complex and
serve just one or many experimenters, investigators or
users.  Payloads can be mounted inside the pressurized
volume of Space Station Freedom or outside on the structural
members or truss.  The outside ones are called attached
payloads.

Like experiments or processes in a laboratory or factory on
Earth, Space Station Freedom payloads will need power,
thermal control, command control, and data systems.

They also need, in many cases, periodic monitoring,
maintenance and perhaps repair.  In some cases, the payloads
may even produce a product that needs to be "harvested" or
retrieved and brought back to Earth.

Some payloads may want to "look" at  outer space while
others may want to "look" at Earth or point towards a
particular star, all at the same time.  This will require
special pointing requirements and a special system to allow
for very accurate and stable pointing.

When one considers the potential for thousands of different
possible experiments and operations over the useful lifetime
of the space station, the challenging role Goddard has in
accommodating all of the potential users becomes more
apparent as does the potential for conflict over station
resources.

The attached payloads will initially be scientific in nature
and sponsored by the NASA Office of Space Science and
Applications.  The disciplines include Solar System
Exploration, Space Physics and Earth Science and
Applications.  These various disciplines endeavor to
understand the origin and fundamental laws of the universe,
and the solar system; to establish the scientific and
technical foundation upon which to undertake both manned and
unmanned explorations of the Solar System, and to
specifically provide a greater understanding of the Earth,
its immediate environment and the  Sun.  Goddard Space
Station Freedom personnel will work with the sponsors and
users of attached payloads to determine how their
requirements can be accommodated by both design and
operations. The user requirements include the following:

---Information - onboard and on the ground
---Transportation - from the Shuttle to the manned base
---Operations Planning - including integration, test and
operation
---External Storage - outside the pressurized volume
---Servicing - for assembly, replacement, replenishment and
storage.
---Verification - integration test & verification of payload
with attached payload accommodation equipment.

Goddard Space Station Freedom personnel will work with the
designers and users to identify and discuss the
accommodation issues in such areas as:

---Crew size - how many and how much time
---Microgravity - how little and how variable
---Available power - how much and where
---Volume - how much and where
---Experimental compatibility - between fundamentally
conflicting experiments
---Payload orientation - with respect to the Earth, stars
and Sun
---Attach points - on the transverse boom
---Distributed payloads - parts that are distributed to
various points.


GODDARD   SPACE   FLIGHT   CENTER


Elements  and  Systems

Free-Flying Platforms
Platforms are unmanned modular spacecraft designed to carry
and support science, technology and commercial payloads that
require exposure to space or that cannot be attached to
Space Station Freedom's manned base for one reason or
another.   They provide facilities for a broad range of
users to conduct long term independent missions and
investigations.   There are two such platforms associated
with the Space Station Freedom's initial capabilities.  One
platform is in polar orbit and is the responsibility of the
United States. The other is a polar orbiting platform  that
is the responsibility of ESA.

Goddard will manage the detailed design development, test
and evaluation of the U.S. polar platform now planned to be
used by the Earth Observing System Program which is also
managed by Goddard.  The Eos program is also part of the
Mission-to-Earth Program which also includes many of the
1992 International Space Year scientific activities.

The first U.S. polar orbiting platform is intended for
continued viewing of the Earth and is placed in a
north-south orbit, thereby allowing the sensors to view the
entire Earth rotating under the platform.  By syncronizing
the altitude (and therefore the orbital period) with the
Earth's rotation and inclination of the sun, the scientists
can be sure their sensors look at the desired locations on
the Earth in  morning and afternoon sunlight rather than
darkness.  This orbit is called sun-syncronous and is 705
kilometers (438 statute miles) and inclined 98.7 degrees to
the equator.  To achieve this, the polar platform must be
launched from Vandenberg Air Force Base in California.
Present planning leans toward the use of a Titan IV
expendable launch vehicle.

The principal goal of the Earth science and applications
discipline, which will be the primary user of this polar
platform, is to obtain a  scientific understanding of the
entire Earth system on a global scale by determining how its
component parts and their interactions have evolved, how
they function, and how they may be expected to continue to
evolve on all may be expected to continue to evolve on all
time scales.  To attain these objectives, the Eos program
will be carried out in conjunction with the National Oceanic
and Atmospheric Administration's (NOAA) weather monitoring
program.

The Eos system includes a complement of instruments on the
platform which will greatly enhance the scientific
communities' ability to gather remotely sensed data on the
Earth's land masses, its oceans, atmosphere and ice sheets.
This data can be recorded on-board and played back to the
ground via the TDRS network or direct broadcast to a ground
station.

The basic design of the U.S. platforms provides for a
significant degree of commonality between both polar and
co-orbiting platforms and the manned base.  These design
studies also look at potential instrument commonalities
between NASA, ESA and Japanese platforms.  Commonality
implies common interfaces for all users.  This should make
logistics simpler, repairs more efficient and costs lower.

The platforms are designed to be serviced in different ways:
by the Shuttle, by rendezvous with a servicing carrier and
by robots on a servicing carrier.


 GODDARD   SPACE   FLIGHT   CENTER

Elements  and  Systems
Flight Telerobotic Servicer (FTS)

The Need
The crew will need assistance in assembling, servicing,
inspecting and maintaining Space Station Freedom and all of
its payloads and systems.  While some extra vehicular
activity (EVA) will still be required, it is more risky and
expensive (in both time and dollars) than if an intelligent
robot could perform some of those functions. One way to get
the various jobs done is to put the astronaut's intelligence
inside the station and put his or her hands and arms
outside.  In effect, this is what a "telerobot"
accomplishes. The term "telerobot" refers to a hybrid
capability for the robot to operate either under direct
control of a human operator (teleoperation) or to carry out
tasks by itself according to some computer rules, knowledge
and sensory information but providing the ability for the
human to intervene.  Another way to get the job done is to
provide the robot with some intelligence of its own for
certain types of jobs.  In effect, this is a "smart robot."
The concept of the Flight Telerobotic Servicer provides a
useful, reliable and safe tool to assist the crew in
performing a broad range of routine tasks on both the
station and the Orbiter.

Design  Concept
The FTS project will soon be evaluating competing approaches
offered by industry.  In preparing for this evaluation, GSFC
engineers developed their own design concept to the same
requirements being studied by the competing Phase B
contractors.  What follows is a description of this
"in-house" design concept.   The actual FTS, to be built by
the successful contractor, is likely to differ substantially
from this description.  The FTS  is an unique element of
Space Station Freedom, unique to spaceflight and unique to
the robotics world.   The FTS is a robot which is also a
spacecraft, and it must be designed and built accordingly.
The FTS must work in a much less structured world than an
industrial robot.  The FTS will be required to perform many
varied tasks with varying degrees of precision throughout
its expected lifetime.  These tasks will increase in
complexity; therefore, the system must be capable of
substantial growth and evolution.

The telerobot is composed of three major subassemblies: the
main body, the arm positioning system and the manipulator
arm assembly.

The Main Body
The main body contains all the major electronic components
of  the telerobot, as well as the grapple fixture by which
the telerobot is picked up by one of the large manipulator
arms, e.g., the Remote Manipulator System (RMS).  The main
body also contains the attachment grapple (or foot) by which
the telerobot is securely fixed at the worksite.

One of the features of the main body of the telerobot is
that it is free to rotate about its central core and the
attachment foot.  This freedom to rotate allows the thermal
radiators that cover three sides of the main body to be
oriented for optimum heat rejection at the worksite.  Main
body rotation with respect to the attachment foot allows the
operator of the large manipulator arm another degree of
freedom to help orient the FTS foot for proper mating to the
worksite attachment point.


The Arm Positioning System
The next major component of the telerobot is the arm
positioning system that consists of two, linearly driven,
tubular sections connected through an offset rotational
joint.  The lower section is free to rotate simultaneously
with respect to both the main body and the attachment foot.
The manipulator arms are free to rotate ? 180 degrees with
respect to the upper section.  Five degrees of freedom are
obtained to position the arms relative to the telerobot main
body and attachment location.  There are a number of
advantages to the arm positioning system: it extends the
reach of the telerobot without extending the length of the
manipulator arms; it allows the arms to be positioned
squarely to a task so that the teleoperator interfaces with
the task in a natural manner; and it allows the telerobot to
reach out over objects which may come between the attachment
fixture and the location of  the task.

The Manipulator Arm Assembly
The final component of the telerobot is the manipulator arm
assembly that is mounted to the end of the positioning
system.  It consists of the shoulder assembly that rotates ?
180 degrees about the end of the positioning system, and
two, 7-degree of freedom manipulators mounted to each end of
the shoulder assembly.  The manipulators are 1.524 meters (5
feet)  long and are configured with a shoulder, elbow, and
wrist.

In addition to the telerobot, the FTS includes two
workstation designs: a stowable work-station in the
Shuttle's aft flight deck and one that will be located
inside Freedom.

Design  Drivers
During the analysis of the requirements and task
capabilities, the Goddard study team identified the
following major design drivers for the FTS:

---Thermal Environment
---Independent Operation
---Manipulator Stability and Positioning
---Safety
---Mobility
---Evolution
---One-G Operation
---Human Interface

The key challenges for each of these design drivers are as
follows:

 ---Thermal Environment - The thermal environment created by
space introduces unique problems in an area that is only a
minor concern for terrestrial robots.  In space, the only
way of dissipating heat is by radiation or conduction.  For
several reasons, radiation was the selected method.  The
peak operating power is in the 1 to 2 kilowatt range
including all the motors, computers, video equipment and
batteries.  The combined effect of all the necessary design
choices produced a thermal design that is independent of
Freedom that will permit indefinite operation of FTS under
most conditions.

---Independent Operation -  The FTS must be capable of
limited operation independent of hard-wired utilities for
power, data, and video from the manned base.  As a result, a
large battery and an RF communications system was included
in the design.  The FTS can never be totally independent of
the space station because it always needs a firm structural
attachment when working.  However, the requirement for
independent operation gives the FTS a tremendous amount of
flexibility, allowing it to work in areas where no utility
ports are located.


---Manipulator Positioning and Stability - Studies of the
size of the Shuttle payload bay and Freedom's truss and
required work indicate that the ideal reach envelope of the
telerobot would be 5 meters (16 feet). If the telerobot is
to work in these  locations, it must be able to cover these
types of distances.  This requires a trade-off of distance
vs. dexterity.  A local mobility system and an arm
positioning system delivers the arms to the tasks.


---Safety - Safety is of primary importance in the design of
the FTS.    The Phase B study approach was to set up a
watchdog safety subsystem that consists of redundant
radiation-hardened computers and associated sensors in the
telerobot to monitor all aspects of the telerobot's
operations and health.  The workstation has a computer that
acts as a global safety monitor for workstation operations
as well as the telerobot safety subsystem.  Whenever any
anomalous condition is detected, the safety computers will
stop all movement of the telerobot.

---Mobility -  The local mobility system that is part of the
in-house concept is a portable rail that can ride out to the
worksite with the telerobot to provide lateral movement.
The portable rail, together with the arm positioning system,
allows the manipulator arms to be positioned with 6 degrees
of freedom at the worksite.

---Evolution - The FTS must be able to evolve towards
greater autonomous operation which will be accomplished
through the incorporation of advanced hardware and software
items as they become available.   The FTS must be designed
to easily accept these changes.

 GODDARD  SPACE   FLIGHT  CENTER


Space Station Freedom Organization

NASA's Goddard Space Flight Center, Greenbelt, Md., is
responsible for development of several of Space Station
Freedom's elements and systems including the free-flying
platforms, attached payload accommodations,
and for planning NASA's role in servicing accommodations in
support of the user payloads and satellites.  Goddard is
also responsible for developing the Flight Telerobotic
Servicer.

As the Work Package 3 Center, Goddard has established the
Level III Space Station Freedom Projects organization to
manage and direct its various development, scientific,
engineering, and support activities.  This organization
reports to the Space Station Freedom Program office in
Reston.

A unique aspect of this organization is its responsibility
to the various scientific, engineering and commercial
communities that intend to utilize the station's resources.
This organization represents the needs of the users by
ensuring sufficient power to their experiments or payloads
and a place for them on the station's truss, a physical
environment that supports their experiments, robotics and
crew services for their experiments, communications with
their experiments, and most importantly, their experiment
data.

This organization currently includes approximately 100 civil
servants.  There are an additional 70 people working on
related activities in other Goddard organizations on such
areas as advanced development, robotics, and testing of
prototype flight hardware.