Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 61
Supplementary Discussion
The bulk of the issues and concerns discussed in this
report resulted from the November 1988 Workshop at the
Academies' Beckman Center. As already mentioned, the issues
identified are not intended to be an exhaustive list. Neither
has the report attempted to highlight all of the good features
of the Space Station program--the committee's energies have
been directed, at the request of the Office of Space Station,
toward issue identification.
The following paragraphs outline several additional
potential issues identified or further elaborated since the
workshop. As the committee has not had the benefit of detailed
briefings on the topics, the committee's conclusions should be
considered tentative.
MATERIALS
Time limitations did not allow the committee to address the
area of Space Station materials in any depth. However, the
committee has some concerns that it feels deserve additional
consideration. One of the most important concerns is the
planned use of aluminum-clad graphite-epoxy structural elements
in at least three areas: (1) for truss segments, (2) for
pressure vessels at 3000 psi, and (3) for structural walls of
the Logistics Module. As is already understood by NASA
designers, the use of this composite material has many
benefits, but it also has the serious drawback of rapidly
degrading in the presence of atomic oxygen after the aluminum
cladding has been pinholed. Members of the committee have
heard estimates from outside sources of as low as 3 years
61
OCR for page 62
62
exposure to the space environment before truss elements might
have to be replaced (for a facility with an intended life of
30 years). NASA is planning to shield critical areas to reduce
the probability of pinholing, but the committee believes that
the potential seriousness of the problem requires further
analysis, especially in assessing its impact on the need for
additional spare parts, maintenance time, and extravehicular
activity. The potential impacts of outgassing from the
materials also needs to be assessed.
HEALTH MAINTENANCE
As was noted earlier, the Space Station's health
maintenance facility is in an early stage of development. The
facility's mission and timing, as well as its relationship to
facilities for health research and extended duration crew
operations activities, still need to be clarified. Moreover,
the committee is concerned that all of the precursor activities
required to allow design of a viable health maintenance
capability may not be being adequately pursued.
For example, it is highly likely that some medical
emergencies on board the Space Station would require the use of
invasive techniques on humans (e.g., minor surgery,
stabilization with IVs). However, U.S. experience to date in
such techniques has largely been limited to drawing blood
samples. One of the Spacelab flights in the early 1990s is
planned to include some experimentation, mainly on animal
subjects, but the committee is concerned that there will not be
a sufficient data base of experience available prior to the
design of the health maintenance facility and its associated
operational concept.
TOXIC MATERIALS HANDLING
An issue that was touched on by the workshop committee
during the NASA presentations on the Fluid Management System
and the life support systems was the handling of toxic
materials. The materials science research activities on board
the Space Station will utilize very toxic substances.
Hazardous materials handling, storage, and emergency isolation
procedures developed for terrestrial laboratories are likely to
OCR for page 63
.
63
be of limited applicability in the Space Station environment.
This issue could be very significant, as its resolution is
likely to have an impact on several Station system designs.
The committee is aware that NASA is devoting some attention to
the issue, but the committee did not have time during the
workshop to assess NASA's activities in this area.
POTENTIAL INCOMPATIBILITY OF USER REQUIREMENTS
The committee is concerned about the potential
incompatibilities of the requirements of different groups of
users, notably between those in the materials sciences and life
sciences disciplines. While NASA clearly is devoting attention
to this area, the committee believes this will remain a
· ~ · -
slgal~lcant Issue.
CREW SAFETY
Various aspects of crew safety were discussed during the
workshop and have been noted in this report. However, time
limitations precluded a systematic examination of
safety-related issues. Several matters of potential concern,
e.g., toxic materials handling, have been identified in this
Supplementary Discussions section. Other possible concerns
include orbital debris, joint Shuttle-Space Station activities,
and the overall state of emergency planning and its impact on
the design process. While the committee has no reason to
believe that NASA is not attaching a high degree of importance
to the resolution of crew safety issues, it believes that crew
safety is an area that will require continued diligence
throughout the design, development, and operational phases of
the Space Station program.
OCR for page 64
Representative terms from entire chapter:
crew safety
