Brandt, Keith

Dervay, Joe

Washington, Andrew

NASA Technical Reports Server

Lessons Learned Conducting 
Spacewalks from the 
International Space Station
Joe Dervay M.D. - Flight Surgeon - NASA Johnson Space Center
Keith Brandt M.D. – Flight Surgeon - KBRWyle
Andrew Washington – ISS Biomedical Flight Controller - KBRWyle
https://ntrs.nasa.gov/search.jsp?R=20170010447 2019-08-31T01:34:35+00:00Z
Disclosure Information
88th Annual Scientific Meeting
Joe Dervay M.D., Keith Brandt M.D., Andrew 
Washington
We have no financial relationships to disclose.
We will not discuss off-label use and/or investigational 
use in our presentation 
Introduction
• From the International Space Station 
(ISS) Flight Surgeon and ISS 
Biomedical Flight controller 
perspective: 
 Review Extravehicular Activity (EVA) 
mission control support, 
denitrogenation (prebreathe) protocols 
and flight rules
 Assess ISS breaks in prebreathe
protocols experienced
 Helmet water intrusion event
 Highlight lessons learned performing 
prebreathe protocols and EVAs
NASA
Methods
• Mission records for US segment 
EVAs in the Extravehicular Mobility 
Unit (EMU) from the ISS Quest 
Airlock
• Analyzed from July 2001 to March 
2017
• Total of 122 two-person EVAs 
(244 astronaut excursions)
• 797 hours total EVA time
• Average 6.5 hours per EVA
• Typical EVA length 5 – 7 hours
NASA
Space Medicine Console Support for EVA
• Mission Control Center (MCC) 
Front room: 
 Biomedical Flight Controller
 Flight Surgeon
• MCC Multi-Purpose Support Room:
 Crew Health Care Systems [CHeCS 
BioMedical Engineer (BME)] Flight 
Controller
 ECG support tech/Nurse
• Increment Management Center:
 Flight Surgeon
• On-Call:
 EVA Prebreathe Subject Matter 
Experts (Integrated Product Team)
NASA
Prebreathe Protocols Used on ISS
• 4-Hour In-Suit (1 use, 2 crew 
exposures)
• Cycle Ergometer with Vibration 
Isolation and Stabilization (CEVIS) 
Exercise 
(21 uses, 42 crew exposures)
• Campout (73 uses, 146 crew 
exposures)
• In-Suit Light Exercise (ISLE) (26 uses, 
52 crew exposures)
Equipment 
Lock
Crew 
Lock
NASA
CEVIS Exercise Protocol and First Use of Quest Airlock
NASA
NASA
LEGEND
On PHA mask breathing oxygen in 
“Emergency” Mode (>95% O2)
Ambient airlock pressure (when 
different from EMU pressure)
Off mask in airlock 
Light Exercise while on PHA or In-suit
In EMU (>99% O2)
In EMU
Monitoring
• Prebreathe
 O2 concentration
 O2 consumption
 Airlock pressures
• During EVA
 Metabolic Rate
 ECG
 CO2
Flight Rules
• Flight rules document pre-
coordinated plans and decisions
• Goal is to minimize the amount 
of real-time discussion required 
to make decisions
Flight Rules
Flight Rules
• Last phase = Most common time to have a break
NASANASA
Breaks in Prebreathe
• Campout:
 Exp 14 - Feb 2007: regulator came off of 
prebreathe mask during depress entering 
overnight campout (break of 2 min, 
2:1 payback)
 STS-124 – June 2008: communications 
cap cable not fully connected, helmet 
removed to reconnect (break of 3:05, 2:1 
payback)
 STS-128 – Sept 2009: communication cap 
chin strap came undone, helmet 
removed to fix (break of 3:30, 2:1 
payback)
NASA
NASA
Breaks in Prebreathe (Cont.)
• Campout:
 STS-129 EVA 2 – Nov 2009: False 
Russian Segment Rapid Depress caution 
during overnight campout early in sleep 
period. Automated response caused 
airlock to repressurize.  Changed to 
CEVIS Exercise protocol next day.
 STS-129 EVA 3 – Nov 2009: 
Bite valve came off drink bag shortly 
after repress to 14.7 psi. Depress 
Airlock down to 10.2 psi to replace 
drink bag to allow unlimited time to 
address issue (no payback required due 
to depress back to 10.2 psi, ~1 hr
timeline hit)
NASA
Breaks in Prebreathe (Cont.)
• ISLE
 Exp 50 – Jan 2017: EMU CO2 removal 
cartridge (CCC) replaced while EMU 
suit fan was on.  The CCC is replaced 
before crew begins EVA to allow full 
CO2 removal for EVA (break of 4:00, 
2:1 payback)
NASA
Lessons Learned from Breaks in Prebreathe
• Develop a common language/terminology between 
communities/flight controllers
• Develop rules for anticipated anomalies/breaks
• Continue to perform simulations to refine prebreathe protocol 
procedures
NASA NASA
Water in the Helmet
NASA
NASA
Water in the Helmet
• July 16, 2013, ESA’s Luca Parmitano and NASA’s Chris Cassidy exited 
the ISS airlock to begin US EVA 23. 
• Roughly 44 minutes into the EVA, Parmitano noticed that the back of 
his head felt wet. The amount of water in the helmet subsequently 
increased and began to collect on his face. 
• Water began to cover his eyes, nose, ears, and communications cap. 
Luca experienced impaired breathing, vision, communication and 
hearing impeding communication. Over 1.5 liters accumulated in the 
helmet.
• The EVA was emergently terminated and the crew made their way 
back to the airlock. 
• Though ultimately Parmitano fared well, aspiration of water could 
have required his crewmates to perform an emergency 
resuscitation. 
Mishap Board Findings
• Inorganic materials caused blockage of the drum holes in the EMU 
(Extravehicular Mobility Unit) water separator resulting in water 
spilling into the vent loop that feeds into the helmet.
• NASA team had a lack of knowledge regarding this particular failure 
mode.
• Similar suit failure misdiagnosis when it initially occurred on a 
previous EVA.
Lessons Learned from Water in Helmet
• Complex systems carry unknown/
unrealized hazards
• Creative Solutions to mitigate risks
- Helmet Absorption Pad (HAP)
- Procedure Updates
- Hand Signals
- Snorkel
NASA
NASA
Summary
• Best plans and training for complex operations should also include 
contingency situations. 
• Continual evaluation of complex operations is required in order to 
improve safety, procedures and other products required for 
execution.
NASA NASA
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Lessons Learned Conducting Spacewalks from the International Space Station

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