Anthropometric and dynamic strength percentile characteristics
The anthropometry and strength data that were collected
from astronaut applicants and astronauts are stored
in a private database at the ABF. As of August 1999,
this database contains information on 809 people.
Various organizations at JSC have asked the ABF to
extract information or perform analyses using this
database for different anthropometric issues such
as space suit fit, glovebox placement, and seat geometry.
The ABF has also used these data to prepare a report
containing anthropometry statistics and percentiles
[ Rajulu, S. L. and Klute, G. K. (1993). Anthropometric
Survey of the Astronaut Applicants and Astronauts
from 1985 to 1991. NASA Reference Publication 1304
]. ABF personnel are currently working on an update
to this report.
Suited versus unsuited human joint strength/performance
The ABF and the Graphics Research
and Analysis Facility have worked together to
evaluate and model human performance when crewmembers
use the pressurized Extravehicular Mobility Unit (EMU).
The subjects in this study performed specific isolated
and multiple-joint motions in unsuited and EMU-suited
conditions using a strength dynamometer, from which
joint torque and angle data were saved. This test
was conducted at the Precision
Air Bearing Floor (PABF) to facilitate proper
positioning and stabilization of the subjects for
the different motions.
Anthropometry and strength measurements for the
astronaut interview/selection process
About every two years NASA picks approximately 120
people from the long list of astronaut
applicants to come for a week of interviews and
tests at JSC. Since 1985, the ABF's role in this process
has been to collect anthropometric data and conduct
musculoskeletal tests on these candidates and some
applicants for other nations' space programs. Each
interviewee spends about 45 minutes in the ABF, during
which numerous anthropometric and joint strength measurements
are taken. These data are printed out and given to
the flight doctors in the Medical Sciences division
for review and consideration in the astronaut selection
process. Because they contain sensitive information,
all printed and software copies of the data are kept
confidential and stored in secure areas.
Hand grasp break-away study
Hand grasp break-away study With the advent of astronaut
deployment and retrieval of satellites and other massive
objects, concerns were raised about whether these
mass-handling tasks would exceed the design-certified
loads for the space suit. It was determined from simulations
of satellite handling tasks that the maximum imparted
load could be calculated from an astronaut's hand
grasp breakaway strength. This is the strength of
the hand while grasping a moving object, which involves
dynamic eccentric contractions of the hand muscles.
ABF personnel conducted a study to document hand
grasp breakaway strengths of astronauts who were scheduled
to perform extravehicular tasks during future missions.
[Rajulu, S. L. and Klute, G. K. (1993). A Comparison
of Hand Grasp Breakaway Strengths and Bare-Handed
Grip Strengths of the Astronauts, SML III Test Subjects,
and the Subjects from the General Population. NASA
Technical Paper 3286]. The results of this study also
revealed that hand grasp breakaway strength cannot
be directly predicted from hand grip strength, which
is the strength of the hand while gripping or squeezing
a stationary object.
Suit Sizing and Laser Scanning
The overall objective of this study was to quantitatively
assess the feasibility of using a Laser
Scanner to make anthropometric measurements needed
for accurate EVA suit sizing. This assessment included
comparison of anthropometric measurements taken with
a laser scanner to those taken with a traditional
anthropometer. Factors included in the assessment
were accuracy, repeatability, potential data yield,
and the time it took to make a measurement. The study
was conducted in three phases. Phase I of the study
compared measurements made with a laser scanner to
those made with a traditional anthropometer and a
digitizer.
While all of these devices come with specifications
of instrument precision, these specifications only
suggest the precision that may be achieved. The indicated
precision may be representative of measurements of
regularly-shaped objects but not of irregularly shaped
objects such as the human body. Phase 1 was intended
to compare how measurements of a complex shape made
with a laser scanner compared with those made with
a traditional anthropometric tool and with a third
device, a digitizer. In phase II, the repeatability,
variability, and consistency of anthropometric measurements
of different human subjects made by different measurers
on different days with the three devices was established.
In phase III, optimal human poses were determined
that yield all of the current suit specific anthropometric
measurements. The accuracy and repeatability of measurements
taken from these posed positions was also determined.
