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Constellation Program (CxP) EVA Systems Test 2 - Metabolic Costs and Biomechanics of Exploration Tasks in a Planetary Suit (IST_2)
Principal Investigator
Research Area:
Behavior and performance
Technology development
Species Studied
Scientific Name: Homo sapiens Species: Human

The Constellation Program (CxP) extravehicular activity (EVA) Systems Project Office (ESPO), which is developing design requirements for the next-generation lunar EVA suit, initiated a series of tests, working with the EVA Physiology, Systems, and Performance (EPSP) Project and the Anthropometry and Biomechanics Facility (ABF) aimed at understanding human performance and suit kinematics under a variety of simulated lunar EVA conditions. These studies included matched unsuited controls in an attempt to identify the specific metabolic costs and biomechanics of the prototype Mark III Advanced Spacesuit Technology Demonstrator (MKIII). A primary goal of the overall test series is to provide evidence-based recommendations for suit mass, center of gravity (CG), pressure, and suit kinematic constraints that optimize human performance in partial gravity environments. Results of this test series will also be combined with studies in other lunar analogs to evaluate the effectiveness and limitations of these environments.

This study, Integrated Suit Test-2 (IST-2), was conducted in the Space Vehicle Mock-up Facility (SVMF) at the Johnson Space Center (JSC) using the MKIII suit because the MKIII is the only planetary suit prototype in NASA’s inventory that is compatible with the partial-gravity simulator, nicknamed POGO. The MKIII also has the most variable operational pressure range of the available prototype suits. IST-2, the companion test to IST-1 (2), had identical objectives and similar test conditions but different test points. Whereas IST-1 focused on level-ground ambulation, IST-2 focused on exploration tasks and inclined ambulation.

The purpose of IST-2 was to move beyond level-ground locomotion and evaluate suited human performance during exploration-type tasks and inclined locomotion. Specifically, the primary objectives of this test were:

  1. Identify the individual contributions of weight, mass, pressure, and suit kinematics to the overall metabolic cost of the MKIII suit in its 121-kg (265-lb.) POGO configuration, including the mass of the Portable Life Support System (PLSS) mock-up and gimbal, which is 29.6 kPa (4.3 psi) during inclined ambulation and exploration tasks in 1/6-g.
  2. Quantify the effects of the following factors on suited and/or unsuited metabolic rate, biomechanics, and subjective ratings during exploration tasks and inclined ambulation:
    a. Suited – varied suit pressure at constant offload, mass, and CG
    b. Suited – varied suit offload (weight) at constant pressure, mass, and CG
    c. Unsuited – varied offload (weight) at constant mass and CG
    d. Unsuited – varied mass at constant offload and CG
  3. Compare the MKIII at POGO configuration to the MKIII at POGO configuration with the waist bearing locked.
  4. Develop predictive models of metabolic rate, subjective ratings, and suit kinematics based on measurable suit, task, and subject parameters.

The secondary objectives of IST-2 did not determine the test protocol. Rather, they are other expected ways for which these data could be applied. They include the following:

  1. Define standard measures and protocols for objectively evaluating future exploration suit candidates and requirements verification of the flight suit.
  2. Understand specific human performance limitations of the suit compared to matched shirtsleeve controls.
  3. Collect metabolic and ground-reaction force data to develop an EVA simulator for use on future prebreathe protocol verification tests.
  4. Provide data to estimate consumables usage for input to suit and PLSS design.
  5. Assess the cardiovascular and resistance exercise associated with partial-gravity EVA for planning appropriate exploration exercise countermeasures.

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Norcross JR, Clowers KG, Clark T, Harvill L, Morency RM, Stroud LC, Desantis L, Vos JR and Gernhardt ML. Metabolic costs and biomechanics of inclined ambulation and exploration tasks in a planetary suit. Houston TX: National Aeronautics and Space Administration, Lyndon B. Johnson Space Center; 2010. NASA Technical Publication NASA/TP-2010-216125.

Norcross JR. Using analogs for performance testing of humans in spacesuits in simulated reduced gravity. Houston TX: National Aeronautics and Space Administration, Johnson Space Center. September 24, 2013. NASA Technical Publication NASA/TP-2013-20140002724. [NTRS]

Extravehicular activity
Oxygen consumption
Gravity, altered
Task performance and analysis

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Data Information
Data Availability
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Center of pressure (COP)
Gait cycle
Gravity compensation and performance scale (GCPS)
Gravity level
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
EPSP 01/01/2006 09/30/2010 4 years, 9 months

Human Research Program (HRP) Human Research Roadmap (HRR) Information
Crew health and performance is critical to successful human exploration beyond low Earth orbit. The Human Research Program (HRP) investigates and mitigates the highest risks to human health and performance, providing essential countermeasures and technologies for human space exploration. Risks include physiological and performance effects from hazards such as radiation, altered gravity, and hostile environments, as well as unique challenges in medical support, human factors, and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify the approach and research activities planned to address these risks, which are assigned to specific Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.

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Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Jessica Keune
Institutional Support
National Aeronautics and Space Administration (NASA)