The new CEV mission requires a launch and re-entry
spacesuit (transition suit) that functions similarly
to the advanced crew escape suit (ACES) yet provides
more mobility and adjustability. The Constellation
Transition Suit Mobility Requirements analysis entails
integrating information from three tests to characterize
the mobility of the ACES suit. This information will
be to develop quantitative and verifiable standards
that will provide the basis for the mobility-related
design constraints and requirements to which new spacesuit
prototypes must adhere. The test consists of (1) isolated
joint range of motion tests, (2) functional mobility
tests and (3) isolated suit joint stiffness tests
for pressurized and unpressurized conditions. Isolated
joint ranges of motion will be measured using data
obtained from the Vicon™
motion capture system. A full-body biomechanical model
will then be utilized to analyze the motion data and
calculate the angles associated with each isolated
joint movement. Functional mobility testing and joint
stiffness information will augment the joint range
of motion data to determine if joint mobility is adequate
for tasks the astronauts are expected to perform in
various prototype suits.
Advanced Space Suit Joint Mobility Study
The
ABF has been assisting personnel in NASA's Crew
and Thermal Systems Division in the evaluation of
three advanced space suit prototypes. The
ABF's role
in these evaluations is to compare the mobility of
the suits by collecting motion analysis data while
subjects perform specific joint motions when wearing
each suit. Once all of the motion analysis data are
analyzed, the results will provide insight on how
each suit affects a particular subject's joint mobility
in relation to his/her unsuited motions, plus reveal
the differences in mobility between the three suits.
Advanced space suit evaluations at remote field
sites
NASA's Crew and Thermal Systems Division personnel
conducted remote field site evaluations of the Mark
III advanced space suit. These tests focused on the
functional mobility of the Mark III as a suited subject
walked around and performed geological survey tasks
in rugged terrain. By videotaping these activities,
ABF personnel were able to determine the suited subject's
mobility by utilizing motion analysis techniques.
These evaluations are conducted near Flagstaff, Arizona
and Death Valley, California.
Planetary Suit Launch Comfort Study
The goal of the Planetary Suit as Launch and Entry
Suit Consideration Test was to determine if a crewmember
wearing a prototype suit designed for planetary exploration
could remain in a recumbent position for two hours
while maintaining a functional range of motion. Subjects
lay on their backs in the launch position while providing
feedback on level of discomfort, and periodically
performing five simple joint articulations to determine
whether joint range of motion was affected or not.
Extra-Vehicular Mobility Unit (EMU) Work Envelope
The purpose of the EMU Work Envelope study was to
determine and revise the work envelope defined in
NSTS 07700
“System Description and Design Data
– Extravehicular Activities”. Using an
optical motion capture system several test subjects
were filmed while performing a one and two-handed
grasping tasks while wearing the pressurized EMU.
Subjects were instructed to work with their arms and
hands in a series of positions in such a manner that
the outer and inner boundaries of their work envelopes
were defined for each task.
Walk Back Test
The Advanced EVA Walkback test conducted at the Partial
Gravity Simulator (POGO) was designed not only
to asses the maximum walking distance a suited crewmember
can locomote back to an outpost in the event of a
rover breakdown during exploration operations of celestial
bodies, but also to collect human performance data
relevant to optimizing space suit design for the targeted
operational environment. This involved performing
tests with matched shirt sleeve controls so that the
biomechanical costs of the suit could be understood
across a range of gravity levels and ambulation speeds.
Post-test analyses were performed on the kinematic
variables of interest which included hip, knee, and
ankle range of motion (using ViconTM), stride frequency,
and stability of the body during the tests.
Autonomous Motion Analysis System
Human-work interface issues in reduced gravity environments
are, in many ways, different from those that we normally
encounter on ground. With a lack of gravity, body
postures change significantly and these changes affect
how humans use work-aids and interfaces. Unfortunately,
these human-work interface issues and suit issues
require whole body mobility tracking systems that
can operate autonomously and under any realistic work
conditions. ABF personnel are currently working with
motion analysis equipment manufacturers (
Measurand & MetaMotion)
to develop new full body motion capture system that
is portable, wireless, and can work inside as well
as outside a pressurized space suit. The development
of an autonomous motion analysis system will allow
engineers to study and analyze the movement of the
astronaut within the suit to evaluate human performance,
space suit design, and extra-vehicular activities.
