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SPACE STATION FREEDOM PROGRAM Vol.2, Number  4
April 1990


Freedom Program Preparing for Future Space Exploration Missions

"Evolution is something we need to plan for, and it is imperative for the
Space Station Freedom program," Dr. Earle Huckins, director of Space
Station Engineering , told more than 600 people at a Space Station Freedom
evolution conference.

"The station is a permanent facility -- a long-term mission," Huckins
said.  "Users' needs will change and technology will evolve.  The real
challenge is to assure systems do not become obsolete."

Discussing these challenges with designers and advanced planners was the
theme of the Space Station Evolution Symposium "Beyond the Baseline" in
League City, Texas, in February.  Attendees heard the results of system
studies and advanced development activities funded under the Advanced
Programs Division.

If Freedom is to meet changing space policy and future user needs, as well
as achieve its full potential as an orbiting laboratory, transportation
port, and servicing facility, today's baseline designers must understand
what the future may hold.  "It is imperative that we design and build the
baseline Freedom to accept new technology," said Steve Cook, policy
analyst for Space Station Engineering at Headquarters in Washinton, D.C.

We can't bring the station back to Earth for an overhaul like we do the
orbiters and some satellites."

Besides considering upkeep and upgrades, some of the sessions dealt with
what lies beyond Freedom's baseline configuration.  One session focused on
evolution operations and pinpointed specific operations required to
assemble  process, refurbish, and luanch exploration vechilces from low
Earth orbit.  Freedom serves as an assembly platform in these scenarios.
Studies discussed in the session revealed preliminary concepts for
prossing vechilces on orbit, constructed data bases of vehicle processing
operations tasks, and employed automation and robotics to shorten
processing time and reduce extravehicular activities.

While Freedom's role as a spaceport could conflict with the need for a
"quiet" environment for disciplines such as microgravity science, NASA
advanced planners say any conflicts would be addressed by the scheduling
of activities.  First of all, the station probably will not be used as a
spaceport  until several years after the baseline is completed.  Secondly,
vehicle assembly and repair would not be around-the-clock opeatration.
Science activities would be scheduled to avoid disruptive processing
taskes.  In one senario under study, it is estimated that the turn-around
for one lunar vehicle flight per year from Freedom would leave about
two-thirds of the year available for "quiet" science.

Space station evolution planning is directed from the Level I  Space
Station Engineering, in parallel with the baseline program.  The aim is to
keep open future options to expand basic resources, add new capabilities,
and incorporate technological advancements.  To help address these
challenges, Advanced Programs is divided into two interrelated aspects --
advanced systems studies and advanced development.

Advanced systems studies are focused to build upon the knowledge gained
from both maturing system designs and better definition of evolution
requirements, such as expanded research opportunities and the Space
Exploration Initiative.  In fiscal year 1990, three primary products will
be delivered to the station program: A Reference Evolution Configuration
and Associated Engineering Data Book; Baseline Design Requirements and
Accommodations ("Hooks and Scars") by Subsystem (e.g. Data Management
System); and Long-Range Technology Requirements.  The Engineering Data
Book contains time-phased requirements for configuration and subsystem
evolution and thus provides designers with a context for understanding the
implications of near-term decisions on the ability of Freedom to evolve.

During this year's preliminary design reviews, hooks and scars
requirements for each subsystem for added capacity, enhanced performance,
and insertion of new technologies will be documented.  The derived
technology requirements for each subsystem will be documented in terms of
performance levels and maturity  dates.  Advanced development emphasizes
advanced automation and robotics applications and technology development
to improve flight and ground system productivity, to reduce long-term
operations costs and to avoid technological obsolescence.  Advanced
development focuses on four major areas:  flight and ground systems
automation; telerobotics; advanced automation software tools and
processors; and information processing systems.

The station advanced development team is pushing near-term technology that
will enhance the safety and productivity of the crew and the reliability
of station systems.  Advanced development tasks are striving to develop a
knowledge -based system technology that can manage some Freedom operations
with little onboard human supervision.

"In some ways, the knowledge-based system reasons for itself the same way
the human mind reasons.  It will be able to detect problems and either
correct the problem or alert the crew," Cook said.  With this technology,
some operations could be handled by the onboard computers and others from
ground operations.  This, in turn, reduces the crew's housekeeping tasks
and increases their valuable research time.  For example, presenters
during the first Flight Systems Automation session described projects for
automatic system status monitoring, as well as fault detection, isolation,
and recovery for Freedom's distributed systems using knowledge-based
system techniques.  Applying such techniques would mean that crew members
would spend less time tending station operations.

Other examples of efforts underway to improve productivity and reduce
operations costs:

* Telerobotics reduces crew time outside Freedom.  The Freedom
telerobotics program, with its investment in ground remote robot control,
operator/robot shared control, automated assembly, and lab tending is
attempting to reduce the number of extravehicular activities, while
improving astronaut productivity when outside work is required.

* Another telerobotics technology and applications session focused on
improving the productivity of the astronaut and Flight Telerobotic
Servicer combination.

Advanced sensors, control algorithms, and task/spatial planning using
knowlege-based system techniques are under development.  Such a
development will reduce telerobotic task timelines and enable more complex
tasks to be performed by the Flight Telerobotic Servicer (FTS).  A
long-range objective, coupled with increased FTS autonomy, would permit
the remote operation of the FTS by ground personnel.

* Enhancements to station information systems is a key component of
evolution.  Tasks presented in this session seek to dramatically improve
computer system performance and reliability as well as reduce the power
required by station and FTS embedded computer systems.  Work is under way
to ensure that new computer and network technology can be inserted in both
station and Space Station Control Center computer systems during their
long operational lifetimes.

NASA Steps Up Ability to Track Man-Made Debris, Info to Aid Station
Designers

Since an orbiting paint fleck could cause some damage to Space Station
Freedom, NASA is aggressively researching ways to deal with even the most
minute orbital debris.  Learning to detect the man-made debris is
important to the design of Freedom and other future spacecraft.

"We must learn the population density and occurrence of the orbital
debris, so our space station engineers and designers will know how to
protect it from the hits it may receive," said William Djinis, program
manager of the NASA Orbital Debris program at Headquarters in Washington,
D.C.

"NASA has made a considerable effort over the years and is striving toward
understanding the orbital debris environment and its trends," he added.

However, neither NASA nor any other space-faring nation can currently
accurately detect man-made orbital debris from 0.1 centimeter (smaller
than a period) to 1 centimeter (smaller than a penny).

While the trackable orbital debris encompasses 3,000 used rocket stages,
inactive satellites, and a few active satellites, information about the
debris measuring less than 10 centimeters in diameter is slim.  Using new
radar systems, NASA hopes to more accurately measure debris less than 10
centimeters.  Estimates are based on a linear extrapolation, which has an
uncertainty factor of two to five.  The ability to detect tiny objects may
be important because, for example, a .3-centimeter aluminum sphere
traveling at 6.17 miles per second (32,360 feet per second) has the same
energy as a bowling ball flying down an alley at 60 miles per hour (88
feet per second).  Currently, mathematical models indicate population
densities as a function of orbital altitude, debris particle size, and
future time.  The data are collected from radars, optical telescopes, and
materials returned from space.

Because more data are necessary to build mathematical  models with a
reasonable certainty for spacecraft design, NASA and the U.S. Space
Command are looking toward the Haystack radar and its auxiliary, the new
Near Earth Assessment Radar (NEAR), close to Boston, Mass., for some
answers.

NASA will spend $15 million in 1990 and 1991 to develop and build NEAR and
NASA will get observation time on Haystack and NEAR.  NASA will use
Haystack data until usable data start filtering in from NEAR in about two
years.  The agency is planning to build a new radar near the equator in
the late 1990s to aid the measuring of orbital debris.

"Space Station Freedom engineers can use the data to conduct a sound,
well-structured design process," Djinis said.  Data from the Long Duration
Exposure Facility, which was returned to Earth in February, also will help
designers understand how to protect Freedom from near microscopic
bombardments of orbital debris to larger pieces of space junk.

As new data have been collected from other sources, the math models have
been updated.  The current 1984 model, being used for spacecraft design,
has been updated as a result of obtaining new data.  This 1988 update is
being used for hazard and risk analyses, but not yet for spacecraft
design, as it has the same degree of error (factor of 2 to 5) as the 1984
model.


NASA's First Space Walk in More Than Five Years Set for November#

In November, astronauts will step out the door 243 nautical miles above
Earth for the first NASA space walk in five years, or as it might be
better described, a space ride.

Shuttle mission STS-37 crew members Jerry Ross and Jay Apt will conduct
the Crew and Equipment Translation Aid (CETA) flight experiment in the
payload bay of Atlantis.  Ross and Apt will try three different methods of
propelling a small cart along rails in the bay in an effort to identify
the best way to move on the exterior of Space Station Freedom.  Necessity,
good timing and enthusiasm have pushed CETA a long way in a short time.

"EVA's are something it's easy to get people excited about," said Ed
Whitsett, CETA project manager at the Johnson Space Center.  "People have
been willing to make a lot of sacrifices to pull this all together."

CETA didn't exist until June 1990, after the final payload review for
STS-37 had already taken place, Whitsett said.  But the experiment,
through long hours put in by those supporting it, came together and was
ready for the previously scheduled launch of STS-37 this June.  The flight
crew played a large part in getting the experiment on track for the
prospective launch date.

Although mechanical tests and procedure checks of CETA are the primary
reason behind the space walk, an important contributing factor is the
simple need for NASA to take a walk on the high side again.

"We're excited about it," explained Ross, who will make his third space
walk.  "We're anxious to build up the EVA team again, to build up the
experience base.  We see a large quantum jump ahead in the amount of time
spent doing EVA as space station gets closer."

The five-year lapse has taken a toll on experienced EVA personnel
available among astronauts, flight controllers, engineers and other team
members.

"The crew needs to get operational experience for EVA's and we need to get
EVA inputs for space station design -- it's a perfect match," Whitsett
said.

By coincidence, Ross was the last American to shut the door on space,
after conducting two space walks on Atlantis (STS-61B) in late November
1985.

"When I got back inside after my second EVA on 61B, I thought that was the
finale . . . I'd never have that opportunity again," Ross said.  "But
through a strange twist, I'm going to do this one.  You know, I smile a
lot thinking about it.  It is really a fantastic experience you just can
never fully explain to anyone."

A method for crew members to move up and down the 400-foot long space
station truss structure has always been planned, but the original concept
was akin to a large space golf cart.

"We thought it was overkill," Whitsett said.  "It was like taking a bus
when all you need to do is goout to the back field on your motorcycle."

Although the simplest method of movement would be a hand-over-hand pull
down the truss, with no special equipment except a tether, such a method
could cause excessive wear and tear on the truss and suit.  Also, it would
be difficult to carry cargo.

CETA may be the answer.  It is a small cart that runs along a track which
can be built into the Space Station Freedom truss.  Astronauts would ride
prone on CETA, and could pull equipment along behind them.

But how to propel the cart, how much stress the various methods of
movement would put on the truss and the astronaut, and how fast it can be
comfortably and safely moved are questions to be studied on the November
mission.

The cart will be mounted on a track in the payload bay, skirted by two
handrails for half of the bay and by one rail, to be extended following
deployment of the Gamma Ray Observatory (GRO), for the entire distance --
46 feet.

Apt and Ross will move the cart in three different fashions: lying prone,
one crewman will pull himself along the track hand over hand; with the
astronaut angled upward slightly, the cart will be changed to accommodate
a lever that can be pumped to move it up and down the track, much like an
old railroad handcar; and, also with the crewman at about a 45-degree
angle, the cart will be propelled by hand-pushed pedals similar to a
bicycle -- the pedals will generate electricity to drive the cart.

The first two versions of CETA are called the manual and mechanical cart
designs.  The third is the electrical design.  All of the versions include
brakes and provisions for moving in reverse, which, for the electrical
version, consists of turning the pedals backward, creating a reverse
current that, in turn, drives the electrical motor backward.

Ross and Apt will evaluate the amount of energy required to move each
version; comfort; how secure they feel moving in them; control; and
visibility.

Sensors on the track and cart will provide information on the amount of
stress each version places on the track and handrails.  Although CETA is a
one-person cart, Ross and Apt also will propel themselves "piggyback" on
each version to test the cart's cargo-carrying ability.

The astronauts also will test a one-person "tether shuttle," a very
simple, small cart designed to attach a tether to so it can slide along as
an astronaut pulls hand-over-hand along the railway.  The "tether shuttle"
is intended as a way for one crew member, carrying no extra cargo, to move
around if the  cart were in use or broken.

CETA will take up most of the single, six-hour space walk planned, but Apt
and Ross will do some additional tasks.Using the Shuttle's robot arm, they
will evaluate how much flexibility can be allowed in the Astronaut
Positioning System (APS) and how quickly an astronaut can be moved
comfortably at the end of an arm.  The APS is a manipulator arm planned
for use when astronauts begin assembling the truss structure for Space
Station Freedom.  It will move an astronaut, standing in foot restraints
at its end, from place to place to assemble the various joints.

Using the Crew Loads Instrumented Pallet (CLIP)--an EVA working station
mounted on the side of the shuttle's bay--the astronauts will gather more
information on stresses imparted to structures during space work.  The
pallet part of CLIP has flown twice aboard the shuttle.

The results of CETA and the other EVA experiments scheduled on STS-37
could make some designs for Space Station Freedom space walk aids less
complex, Whitsett said.  "It has been kind of a crash program, but there's
been a real fine team," Whitsett said.  "It's fallen into place quickly
and smoothly."

The launch of STS-37 originally was scheduled for June, but it has been
reset for November.  The delay is disappointing for those who've worked on
CETA, but the extra time won't be wasted.  "The time will allow for some
things we were a little pressed on to be double-checked."


Space Station Freedom Evolution Workshop: The User Perspective

The following is a synopsis of a presentation by Robert Rhome, assistant
associate administrator for the Office of Space Science and Applications
(OSSA) for space station at the Space Station Evolution Workshop held in
League City, Texas, February 6-8, 1990.

The plans for Space Station Freedom and its evolutionary path harmonize
well with the three major goals of the Office of Space Science and
Applications (OSSA):  to advance scientific knowledge of the planet Earth,
the solar system, and the Universe; to understand the effects of the space
environment on biological and physical processes; and to expand the human
presence beyond the Earth into the solar system, said Bob Rhome.

OSSA envisions that, over the next several decades, the frontiers of space
will have been greatly pushed back and mankind's knowledge will have been
significantly enhanced through a number of space initiatives.  Space
Station Freedom very naturally extends OSSA's ability not only to provide
critical, on orbit, long-duration space research, but also to extend its
current research infrastructure substantially beyond existing
ground-based, suborbital, Shuttle and Spacelab facilities.

OSSA's Strategic Plan lists as one of its five major themes, "Transition
to Space Station Freedom." In keeping with that commitment, each of OSSA's
science disciplines has developed specific objectives for the use of
Freedom and has initiated plans for the development of hardware facilities
and payloads. These goals and objectives remain relatively constant
through the "beyond the baseline" -- or post-assembly complete -- era.

Those divisions planning to place attached payloads aboard Freedom
(Astrophysics, Earth Science and Applications, Solar System Exploration,
Space Physics, and Communications and Information Systems) intend to study
the galaxies and intergalactic and interstellar media; make comprehensive
global observations; search for other planetary systems and study cosmic
rays and cosmic dust; perform solar physics observations; and advance data
dissemination, analysis, and archiving technology.

The microgravity science disciplines planning to perform experiments using
mainly the pressurized volume intend to explore the effects of near-zero
gravity on various materials, fluids, combustion processes, and biological
systems.

OSSA has established a number of strategic guidelines for science
utilization evolution to space station:

* Treat station utilization as an integral element of the overall space
science program;

* Ensure that station is the appropriate platform for the science in
question;

* Avoid duplications and maximize user opportunities by coordinating plans
among science groups (U.S. agencies, international partners).

OSSA believes in taking an evolutionary approach to station utilization,
relying on modest experimentation initially, and then introducing more
ambitious experiments as we "learn how to use the station."

However, the advent of the Space Exploration Initiative poses the
possibility of the station becoming a transportation node.  In order to
formulate a coherent, meaningful, long-term space science program, a
minimum of four years of concentrated science effort to understand the
underlying fundamental phenomena is essential.  The science "window of
opportunity," as  it is called, in which the station is a viable
space-based research laboratory, must be sustained (see figure, page 5).

The accommodations issues with which OSSA is concerned relative to the
post-assembly complete era are similar to those expressed relative to the
baseline station during the space station rephasing.  The user
requirements for power, crew, and data handling, laboratory support
equipment, and attached payload accommodations will continue to grow.

The long-term research requirements of the United States will likely
exceed the capabilities available through barter for a man-tended
free-flyer for inten-sive microgravity research.

Consideration may well be needed for a U.S. free-flyer in the first decade
of the 21st century.

The heritage for the development of Space Station Freedom stemmed from the
need to establish a research laboratory in space.  In 1987, Andrew J.
Stofan, then associate administrator for space station, stated, "The space
station is first and foremost a research laboratory.  We are building an
orbiting laboratory -- for the conduct of science, the development of
technologies and the stimulation of commercial space enterprises."

Once established, a space-based research laboratory capability must not be
lost in the evolution toward a transportation node.

Studying the Galaxy:  A Superconducting Magnet Facility

When President Reagan announced in January 1985 the intention to build a
permanently manned space station, the high energy astrophysics science
community recognized it as a chance to finally permit the accommodation of
a large superconducting magnet in space.  Such a magnet would allow
particle physicists to study, from space, the origin and evolution of
matter in the galaxy, perhaps shedding some light on the age-old question
of the origin of life itself.

Substantially strengthened by international involvement, Astromag study
activities have involved foreign science participation from the beginning.
The Italian Space Agency (ASI) has offered to make a major commitment to
the Astromag project, and discussions continue toward developing the core
facility as a joint U.S.-Italy project.  Furthermore, there are
international co-investigators on all three of the investigations selected
for Astromag.

The Facility.  NASA proposed the Astromag facility as an attached payload
in an announcement released in June 1988.  A year later, three particle
astrophysics investigations were selected for the Astromag superconducting
magnet facility, to be flown as a U.S.-Italy project on Space Station
Freedom in the late 1990s.

The science goals include: investigating the origin and evolution of
matter in the galaxy by direct sampling of galactic material; examining
cosmological models by searching for antimatter and evidence of the nature
of dark matter;  and studying the origin of extremely energetic particles
and their effects on the dynamics and evolution of the galaxy.  The
investigations that Astromag is designed to perform can only be done in
space; the energetic particles that will be examined by Astromag do not
reach the ground.

Astromag is a superconducting magnet facility consisting of the core
facility and auxiliary detectors capable of measuring the charge, mass,
energy, and arrival directions of primary cosmic rays.  The core facility
is comprised of the magnet and cryostat, along with the data, power, and
command interfaces.  By augmenting the strong magnetic field with a
variety of specialized detectors, state-of-the-art spectrometers will be
used to ad-dress Astromag's experimental objectives.  For example,
measurements of high energy cosmic ray nuclei and electrons will be made
with precision and sensitivity 10 to 100 times that of previous
experiments.  The space station is an ideal platform for Astromag because
it provides both the assembly and servicing capabilities needed for
change-out of experiments and replenishment of liquid helium to extend the
life of the facility.

The Investigations.  Astromag is designed to accommodate at least two
experiments operating simultaneously, and to allow for change out and/or
servicing as required.  The first-generation investigations will provide
unprecedented information about nucleousynthesis, cosmic ray origin,
acceleration regions, and the possible existence of antimatter.  The three
investigations selected as part of the facility are: A measurement for
cosmic rays (Wizard), the Large Isotope Spectrometer for Astromag (LISA),
and the Spectra, Composition, and Interaction Study using a
Magnetic-Interaction Calarimeter (SCIN-MAGIC).

WIZARD.

Wizard will investigate cosmic ray antiprotons, positrons, and light
nuclei (such as those of helium and lithium) and search for primordial
antimatter.  These studies are among the highest priority goals of
particle astrophysics research, which was cited by the National Research
Council's Astronomy Survey Committee as key to understanding violent
events in the universe .  Robotic installation, maintenance, and removal
of the experiment are planned.

The Wizard experiment uses an array of particle detectors mounted in a
strong magnetic field at one end of the facility, and consists of a pair
of time-of-flight detectors, a tracking system, transition radiation
detectors, and a calorimeter.  The time-of-flight detectors and the
tracking system identify primordial matter.  The Wizard data will provide
information on the matter/antimatter asymmetry of the universe, the mini
black holes, and the role of the Grand Unified Theories in the early
universe, all of which are relevant to both cosmology and elementary
particle physics.

LISA.  One of the fundamental but unanswered questions of cosmology is the
degree to which the universe contains antimatter.  LISA will address the
issues of: the origin and evolution of galactic matter; the acceleration,
transport, and time scales of cosmic rays in the galaxy; and the presence
or lack of antimatter.  The relative abundances of the elements and
isotopes in galactic cosmic rays represent a record of the history and
samples of matter from other regions of the galaxy, including the
synthesis in stars, its acceleration to high energy, and its subsequent
nuclear and electromagnetic interactions with interstellar medium.

LISA is a cosmic ray isotope spectrometer designed to identify isotopes in
cosmic rays, conducting high precision measurements to better our
understanding of galactic material from beyond the solar system.  LISA's
various detectors measure particle charge, velocity, momentum, and
coordinates in a magnetic field.  By combining the individual measurements
of these instruments, it is possible to identify nuclear charge, isotopic
mass, and whether the particles are matter or antimatter.

SCIN-MAGIC.  Cosmic ray particles appear to contain nuclei of all elements
found on Earth.  Pervading the galaxy, and probably beyond, cosmic rays
are a probe of high energy processes occurring in the galaxy, and their
origin and acceleration are closely linked to the origin of the elements
themselves.  SCIN is a high energy nuclear physics/particle astrophysics
experiment that will use the astromag facility to search for a new state
of matter (quark-gluon plasma), as well as for measurements of cosmic ray
energy spectra near the region where dramatic changes in nuclear
composition are expected.  SCIN investigations will be carried out under a
U.S.-Japan collaboration.


NEWS BRIEFS

* NASA's Space Station Freedom program and the Italian Space Agency (ASI)
are discussing ways that could increase the ASI's space station
involvement.  Officials from both organizations signed a joint study plan
to investigate ways the ASI could contribute to the station.  The ASI is
already a member of the European Space Agency (ESA), contributing about 25
percent to ESA's overall budget.  ESA has 13 member countries.

* NASA and Italian officials met at the Marshall Space Flight Center in
Huntsville, Ala., last month.  Both groups are planning another meeting in
Rome at the month's end.

* Space Station Freedom's international partners are gearing up for their
preliminary design reviews later this year.  The European Space Agency's
preliminary design review for its attached pressurized module,
Columbus, is scheduled for August.  The Canadian Space Agency's program
design review of the mobile servicing system is also set for August.  The
preliminary design review for the Japanese Experiment Module is set for
December.

* NASA officials are set to testify about the agency's overall $15.1
billion 1991 budget request before the Senate Appropriations Veterans,
Housing and Urban Development, and Independent Agencies Committee on April
26.  A hearing on the Space Station Freedom program's $2.45 billion 1991
budget request is set for May 15.

* The House Space Science and Applications Authorization Subcommittee and
the Senate Science, Technology, and Space Subcommittee began making their
changes to NASA's 1991 budget request in March.  NASA Administrator
Richard Truly also testified about NASA's budget  request for 1991 before
the House Appropriations Veterans, Housing and Urban Development, and
Independent Agencies.

* The Tier I draft of the environmental impact statement (EIS) for Space
Station Freedom was sent to the Environmental Protection Agency in March.
Public comment on the draft ends April 20.  Space Station Freedom is not
expected to cause significant environmental impacts in normal operation,
according to the draft EIS.

* The first Investigator Working Group for space station attached payloads
is set for April 3-5 in Columbia, Md.  The meeting will cover topics such
as payload accommodations and facilities.  For more information, contact
Cathy McIntyre at 301/290-6000.