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Constellation Space Suit System

CSSS

NASA recently held a Constellation Space Suit Systems (CSSS) Industry Day to discuss he design, development, certification, production, and sustaining engineering of a space suit system to meet the needs of the Constellation Program.

Mission Description

* ISS/CEV - Provide LEA, limited duration pressurized survival, and contingency EVA (zero-G) capability for missions to ISS for up to 6 crewmembers
* Lunar Sortie - Provide LEA, extended duration pressurized survival (up to 120 hours), zero-G EVA capability, and surface (1/6-G) EVA capability for a lunar mission (~ 2 weeks, 1 week on surface) for up to 4 crewmembers
* Lunar Outpost - In addition to above, provide surface EVA capability for a lunar mission duration of up to 6 months
* Mars - Surface operation EVA capability on Mars for extended duration

Space Suit System Architecture

NASA perceives that a single suit system providing LEA, zero-G EVA and surface EVA capabilities is a feasible approach and potentially offers the following:

* Reduced upmass
* Reduced logistics and sparing
* Reduced life cycle costs

Technical and schedule challenges suggest that a phased or block approach may be required

* LEA and zero-G EVA capability to support by the first flight of CEV, NLT 2014 with a programmatic goal of 2012
* Surface EVA capability is required for first lunar sortie missions, NLT 2018 with a programmatic goal of 2015

Soliciting Industry input on the above

Suit System Goals "Outcomes"

* Minimize life cycle cost
* Minimize system operational overhead and maximize work-efficiency over the entire suit use cycle
* Minimize system mass and volume and carry weight
* Maximize unpressurized mobility to allow crewmembers to operate vehicle systems and to perform in emergency situations
* Maximize EVA capability while limiting impact on unpressurized suit volume, weight, comfort, and other attributes necessary to fulfill the crew survival function
* Maximize quick donning capabilities
* Accommodate the full-range of flight crew anthropometries while minimizing the required suit logistics
* Maximize reliability and minimize maintenance requirements
* Minimize operational/design constraints for conducting lunar surface operations with respect to geographical location and solar/thermal conditions
* Incorporate, where appropriate, design flexibility and modularity to allow for efficient incorporation of upgrades

Assumptions Affecting EVA Suit System Hardware for all Mission Phases

General Assumptions:

* No prebreathe before launch
* Crewmembers will be able to self don and doff the suit while in vehicle(s)
* The CEV cabin has the capability of being pressurized at 10.2 - 14.7 psi
* All crewmembers are suited and connected to vehicle life support system during majority of flight phases
* There can be water-egress scenarios (in water duration TBD)
* Contingency EVAs will not be used as an immediate emergency response
* Biomedical instrumentation / suit system feed back to the ground via other vehicles will be required
* Hardline and/or wireless voice/data infrastructure will be available on all vehicles
* CEV and LSAM can provide basic life support capability to suits if vehicle(s) become unpressurized
o Conditioned Air
o Water cooling
o Oxygen
o Power / Communication
* Depressurization of vehicles and operation of hatches may be accomplished from either side by a single member of the crew without tools
* Suited pad emergency egress in addition to Launch Abort System will be available

CEV/ISS Phase Operational Assumptions

ISS Phase Assumptions:

* Up to 6 crewmembers in CEV per mission
* The nominal CEV cabin pressure is 14.7 psi
* Not less than 3 crewed missions to ISS per year

ISS EVA/Pressure Suit Related Unknowns

* Suit use for Bends Treatment
o The suit may be required to provide a treatment capability for Decompression Sickness (DCS) by providing to the crewmember a minimum of habitat + suit operating pressure + 4 psi
* Amount of crew survival gear operationally driven to be attached and/or integral to suit
* Seat interface to suit
* Maximum time to survive a vehicle depressurization

ISS EVA Option

* Primary goal is to procure a suit system to meet Constellation mission requirements
* The Government would like to evaluate the feasibility of utilizing this system to support ISS EVA requirements, without degradation to Constellation mission performance
o Potential cost savings to NASA to sustain a single suit system
o Reduced logistics to ISS
o Opportunity to demonstrate performance prior to sortie missions
* Information pertaining to current ISS Suit (EMU) and related environments will be posted on the procurement website

Lunar Sortie Phase Operational Assumptions

Lunar Sortie Phase Assumptions:

* Up to 4 crewmembers in CEV / LSAM per mission
o All 4 crewmembers can descend to surface in LSAM
o Up to 4 crewmembers can go EVA simultaneously
* The LSAM cabin has the capability of being pressurized at 8-10.2 psi
* LSAM airlock remains on the lunar surface, if there is an airlock
* Surface suit components can be stowed in the LSAM
o No pre-positioning of hardware on surface for sortie flights
* Need capability to perform a contingency EVA transfer between LSAM and CEV
o LSAM and CEV side hatches will be sized appropriately for pressurized suits to pass through. Assume both vehicles have identical umbilical connections
* The crew can be safely returned to earth within 120 hours from any point in a lunar mission (including from the lunar surface), even if the CEV is depressurized
* Surface stays are restricted to lunar daylight (however suit should not constrain timeline)
* LSAM will have capability to land on majority of lunar surface including polar regions
* Flight rates of up to 2 per year

Lunar Sortie EVA Operational Unknowns

* Traverse distance required for planned lunar EVAs
* Quantity & duration of EVAs planned for sortie missions
* Which if any surface suit components will be left on lunar surface or in LSAM ascent module (disposability)

Lunar Sortie Phase Challenges

Team is currently defining detailed EVA operations concept

Below are few examples of scenarios under review that present significant challenges to multi-capability suit system design

* Crew survival during CEV vehicle depressurization
o Return scenarios from the lunar surface could require up to 120 hours of unpressurized survival
o Nutrition, waste management, and other life support functions must be maintained
* Crew survival during LSAM depressurization (while separated from CEV)
o Suit system must accommodate vehicle transfers
o Suit system must be able to accommodate various functions (i.e. reconfiguration) without necessarily requiring doffing of entire system
* Suit operations during & post lunar sortie missions after exposure to lunar regolith
o Minimize dust in crew habitable space
o Maintaining suit system performance

Suit Technology Development

Technology development is required prior to design of a Portable Life Support System for lunar surface EVA

* Apollo and EMU era technology would have several key performance, system mass/volume, and reliability drawbacks
o Although the Apollo suits were successful in supporting the mission goals for that program, the designs would not be acceptable from a performance, reliability, and safety perspective if today's standards and mission requirements were applied

Contemplated approach

* Target development of EVA lunar sortie technologies to address key performance, system mass/volume, and reliability capabilities necessary to support the Constellation Program's long-term goals

Starting in FY06 thru FY07 the Government has begun and will continue to pursue various technology development activities in the areas of

* Life Support Systems (including power)
* Pressure Garment
* Communications, Avionics, and Information (CAI) Systems
* Analog Testing

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