Risk of Impaired Control of Spacecraft /Associated Systems and Decreased Mobility

Transcription

1 Risk of Impaired Control of Spacecraft /Associated Systems and Decreased Mobility Due Impaired to Vestibular/Sensorimotor Ability to Maintain Control Alterations of Associated Vehicles and with Other Space Complex Flight Systems Scott Wood Azusa Pacific University NAS Workshop on NASA s Evidence Reports on Human Health Risks July 25, 2016

2 How well is the risk understood? 1. Evidence from spaceflight operations: Apollo landing disorientation & rover operations Falls during Apollo lunar EVAs Docking and teleoperator performance mishaps Shuttle crews self-rating on ability to emergency egress Shuttle landing performance, post-flight exams Conclusions: This line of evidence from operational data is somewhat equivocal owing to uncontrolled (and/or unmeasured) environmental and/or engineering factors (p 8) Controlled studies correlating sensorimotor & operational performance (e.g., FTT, Field Test) were therefore needed to further define this risk

3 Shuttle landing Shuttle Training Aircraft (STA) from Figure 1, page 12

4 How well is the risk understood? 1. Evidence from spaceflight operations: Performance measures reflect high degree of intercrewmember variability as with sensorimotor measures Multifactorial nature of most operational evidence based on performance ( a combination of physiological, behavioral, environmental, and engineering factors, p 8) Example: Pilot induced oscillation (PIO) during STS-3 landing may be noteworthy as an unrecognized case of spatial disorientation in a highly experienced pilot (p13); however, autopilot test during landing resulted in late manual takeover was likely a contributing factor 4

5 Evidence of risk for long-term missions? 2/3. Evidence from inflight & post-flight science investigations: Data reflect a high degree of inter-crewmember variability Most compelling evidence obtained during recent post-flight ISS experiments: Functional Task Test (FTT): Functional tests requiring a greater demand for dynamic control of postural equilibrium (e.g., seat egress) showed the greatest decrements in performance (Bloomberg et al., 2015) Field Test: Level of functional deficit observed within hr of landing more severe than expected (Reschke et al., 2015) Manual Control: Significant impairment in operator proficiency for piloting and driving tasks within 24h after 5 ISS landings (results not available for this edition)

6 Evidence of risk for long-term missions? Example from one subject performing T38 landing from Moore et al., 2015 report 6

7 Evidence of risk for long-term missions? 2s n=7, from Moore et al., 2015 report 7

8 Sleep restriction effects? from Beltran et al., 2015 Manual Control Sleep Restriction Ground Control Study: 30 hrs restriction resulted in comparable increases in sleepiness using Stanford 7pt scale No changes in manual control tasks post-sleep restriction However, there was also no significant difference in PVT reaction time during last test performed in laboratory; while there was an upward trend when away from lab

9 Evidence of risk for long-term missions? Evidence from post-flight recovery must be understood as best-case scenario given the resources devoted to reconditioning (2 hr/day) and limits on crew time activities Table 1 from Wood et al., 2011

10 Named gaps most critical? The gaps that bridge the sensorimotor changes (or other physiological changes) with operational performance are critical for further defining this risk (SM6.1, 7.1, 26) Given the lack of current countermeasures (Table 2), the gaps defining the changes over the course of a mission and recovery (SM2.1) and determining optimal countermeasures (SM27 and 28) should also be considered essential Determining if sensorimotor adaptability can be predicted from preflight tests (SM24), including the use of genomics, is topic of current research (p 71-72) Understanding changes over a crewmembers lifetime (SM2.2) are important for crew health and may be useful for future mission outcomes involving extended exploration 10

11 Additional gaps? One challenge for this risk is the limitations of the current analogs. The report does a good job to reference how investigations have utilized analogs; e.g. bedrest for isolating unloading effects or parabolic flight for acute effects Exposure to sustained hypergravity, e.g. 90m at +3Gx, may be useful analog to examine adaptive changes (Bles et al. 1989, Nooij & Bos 2007)

12 Additional gaps? How similar are post-flight effects observed in 1g with posttransitional effects following lunar (0.16g) or Mars (0.38) gravity landings? Some of the current research in Artificial Gravity may address this issue, but should consider explicitly identifying this as a gap if not already covered by another risk 12

13 Relevant interactions among risks? spatial memory & navigation deficits disorientation & motion illusions gaze disturbances cerebellar ataxia head-torso coordination postural instability motion sickness orthostatic intolerance sleep disruption? (from Fig. 6.1, p138, Goldberg et al., The Vestibular System: A Sixth Sense, Oxford, 2012)

14 Relevant interactions among risks? Risk of adverse cognitive or behavioral conditions and psychiatric disorders Risk of inadequate design of human and automation/robotic integration Risk of inadequate human-computer interaction Risk of impaired performance due to reduced muscle mass, strength & endurance Risk of orthostatic intolerance Risk of cardiac rhythm problems Risk of performance decrements resulting from sleep loss (from Fig. 6.1, p138, Goldberg et al., The Vestibular System: A Sixth Sense, Oxford, 2012)

15 Posturography from Wood et al., 2015

16 Countermeasure evaluation Utilizing the same post-flight measures obtained from previous investigations (e.g., FTT, Field Test) as well as medical operations tests (e.g., posturography) will strengthen the evaluation of efficacy of new countermeasures, especially in crewmembers who participated in these studies during their earlier missions 16