Last Published:  07/31/19 10:05:33 AM (Central)
Short Title: DEFERRED: Prebreathe Validation
Responsible HRP Element: Human Health Countermeasures
Collaborating Org(s):
Other:
Funding Status: Active - Currently funded and in progress
Procurement Mechanism(s):
Directed
Aims:

This task has been deferred and will resume when determined appropriate.

Human research studies are required to validate safe and acceptable prebreathe protocols for exploration mission scenarios. Prebreathe protocols will be developed using models and validated in ground trials using the EVA simulator described in DCS-2 and the Accept/Reject limits developed in that task.

Each proposed PB protocol must be validated for a specific environment due to expected differences in transit time to the destination, operational concepts, mission profile and exploration EVA activities.

Operational concepts still need to mature and studies are still needed to characterize human performance during exploration EVA tasks in order to design an EVA Simulator. Many different scenarios will need to be tested until enough data exist for a valid DCS prediction model. Some of these scenarios include:

  1. Initial 8 hour EVA on location surface from Lander with crew not be completely saturated at exploration environment (currently proposed at 8 psi/32% O2 but is subject to change).
  2. 8 hour construction/maintenance EVA with crew at exploration environment saturation.
  3. Multiple short EVA excursions from SEV. Expected baseline is 4 x 45 min EVA, 6 days/week. If this scenario is tested during the PB validation, the intermittent recompression study may need to be adjusted.

 

In the past, PB protocols in flight have been able to build in additional safety margin based on operational constraints, but this will not be the case with the Exploration Program.  Therefore, ground based testing must be carried out with the utmost precision and care in relation to simulating the key parameters related to DCS risk.

Additional measures of human performance will be included in this task to characterize the initial hypoxic does of the expected Exploration environment and to provide data on the cost/benefit of a mildly hypoxic environment that allows rapid EVA capability vs. an Earth normal environment with limited EVA capability.


Integration/Unique Aspects: TBD


This task was given ATP but was then put on hold and postponed per HRP Fy17 quarter 3 actions.   This task will resume if determined appropriate by HRP program management.
Mappings
RiskRisk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders
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RiskRisk of Decompression Sickness
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RiskRisk of Inadequate Nutrition
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RiskRisk of Reduced Crew Health and Performance Due to Hypobaric Hypoxia
GapExAtm1: We do not know how mild hypobaric hypoxia in combination with other spaceflight environmental factors will impact the brain (e.g., Visual Impairment and Intracranial Pressure (VIIP) syndrome, Sensorimotor (SM), and Acute Mountain Sickness (AMS) risks).
GapExAtm2: We do not know how mild hypobaric hypoxia in combination with other spaceflight environmental factors will impact exercise countermeasures.
GapExAtm3: We do not know how mild hypobaric hypoxia in combination with other spaceflight environmental factors will impact the immune system and Oxidative Stress and Damage (OSaD).
GapExAtm4: We do not know how mild hypobaric hypoxia in combination with other spaceflight environmental factors will impact sleep.
GapExAtm5: We do not know the O2 prebreathe requirements for DCS mitigation from the 8.2/34 environment (shared with DCS5).
GapExAtm6: We do not know how hypobaric hypoxia affects medical equipment.
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