2.5 Crew Item LaundryCurrently, the ISS has no laundry capability. Laundry refers to washing, with fluid and cleansing agents, to remove soil and odor from clothing, as well as drying to remove any residual fluid from the clothing. On ISS today, all crew clothing, washcloths, and towels, collectively referred to as ‘clothing’, are discarded after they are sufficiently soiled. This requires continual resupply of approximately ~0.5 kg/crew/day to replace disposed items. NASA is considering a simplified approach that provides laundry freshening and some amount of cleaning capability. The simplified system should enable clothing to be reused several times but not indefinitely as with conventional terrestrial laundry systems.2.5.1 Response OpportunityInformation is requested on laundry system technologies addressing all or some of a range of parameters including:•Requirements: utilize <10 kg water/1 kg clothing. Goal: 3 kg water/1 kg clothing.•Any solvent must either be non-toxic, neutralized, or recovered and reused. Any solvent that remains on the clothing, is vented, or escapes through loading clothing is considered a contaminant and provides an additional burden on the vehicle air recovery system.•No fabric brighteners, fragrances, or binders are allowed. Surfactants must be compatible with biological water processing systems.•It is likely that a laundry system will have three phases: solids (clothing), liquid (water, condensed solvent, or surfactant), and gas (air or solvent). All mechanisms for agitation, rotation, fluid dispersion, and fluid separation must have a clear and scientifically based means of operation.•Venting overboard results in loss of cabin gas and water. Drying thru exposure to vacuum is prohibited because it represents a loss of water that needs to be recovered.
I'd never thought of it before, but that's actually quite an interesting problem. It also makes me wonder how laundry is taken care of on a nuclear submarine.
For the ISS, I'd put my money into inventing some form of drying machine (to remove sweat and water) and couple it with a sterilization technology, probably using UV light. I think washing using a liquid may be a waste of time. To me it seems just a bit old-fashioned for a space station.
This problem has already been solved by the best - Robert A. Heinlein himself. I refer you to 'Misfit'. After a spaceship cabin full of men barf all over themselves the local expert (sarge) has them put their soiled clothes in the airlock which is then evacuated (air gone - now a vacuum). A unspecified amount of time later (more than a minute, less than a day) the clothes are removed from the airlock and the residue of barf is brushed off into the ventilation system's intake to be filtered out. Seems like this would work for garden variety armpit-stink as well.
I believe you missed my point. Given sufficient vacuum drying - washing clothes with water is not required. Smelly clothes get that way due to accumulated sweat and other fluids. Vacuum drying rids the clothes of the volatile part of the stink sans water. A little elbow grease with a brush gets rid of the solids - do this in front of the air intake to collect and filter the debris, you don't want to be breathing it! Question is - will this trick work with 'skid marks'?
The problem is that the OP states NASA assumes 'water-and-soap' washing, so vacuum "cleaning" is out simply because the original RFI doesn't allow for it. Which is as usual "ass-backwards" since NASA should be setting out an RFI WITHOUT micromanaging the details...Randy
Dry-cleaningSupercritical carbon dioxide (SCD) can be used instead of PERC (perchloroethylene) or other undesirable solvents for dry-cleaning. Supercritical carbon dioxide sometimes intercalates into buttons, and, when the SCD is depressurized, the buttons pop, or break apart. Detergents that are soluble in carbon dioxide improve the solvating power of the solvent.
Nothing says you can't use a vacuum pump inside of the ISS for the same effect. A vacuum in a vacuum Though, you really don't want to be breathing the vacuum pump exhaust products. They are not healthy... Does anyone know if the "newer" oil free dry scroll pump exhaust products fall under the nasty category? My past experience has always been you exhaust roughing pumps to the outside.
Quote from: RanulfC on 05/21/2010 06:29 pmThe problem is that the OP states NASA assumes 'water-and-soap' washing, so vacuum "cleaning" is out simply because the original RFI doesn't allow for it. Which is as usual "ass-backwards" since NASA should be setting out an RFI WITHOUT micromanaging the details...RandyNo. It isn't micromanaging, it is bounding requirements. The requirement isn't just to clean the laundry, it is to do it within these bounds. Vacuum "cleaning" means losing both water and air.Laundering requires some kind of fluid to dissolve or wet the "dirt' in the garments.
No Jim is IS micromanaging and the proof is in the "bounding requirements" which ASSUMES (as you do) that "cleaning" requires water and air and no other methods need be examined.Any 'vacuum' system can be made to store, scrub, and recycle the air and water as it's drawn out so you lose nothing that's not a technical challenge. Nor for that matter is the NASA RFI since you can BUY "no-output" combined washer/dryer units commecially! What the RFI is basically asking for is ideas for adapting these exisiting machines to microgravity more than anything else.And it's STILL micromanaging because the RFI specifies HOW to do the job rather than asking for ideas on how to do the job! What is needed is an RFI that asks IF "washing" with soap and water is really the most efficent way to clean clothes in space or is there a better method, and if so what would it be?Randy
It is a shame they can't use a clothesline for drying!Clothes dryers are substantial energy hogs, not to mention that gas dryers exhale carbon monoxide that must be vented (along with irreplaceable air). Clothes dryers also present a well-known fire hazard (CPSC says that there are more than 40 dryer fires every day in the U.S.). A clothesline, on the other hand, uses the sun's free energy. On a sunny day, clothes actually dry faster on a clothesline than in a dryer because sunlight can provide more energy per unit surface area than a typical clothes dryer. - Ed Kyle
Quote from: bpb3 on 05/21/2010 06:08 pmI believe you missed my point. Given sufficient vacuum drying - washing clothes with water is not required. Smelly clothes get that way due to accumulated sweat and other fluids. Vacuum drying rids the clothes of the volatile part of the stink sans water. A little elbow grease with a brush gets rid of the solids - do this in front of the air intake to collect and filter the debris, you don't want to be breathing it! Question is - will this trick work with 'skid marks'? I think the issue is if the clothing has sweat embedded in it; a long-duration closed-loop life support system would ideally reclaim that sweat and recycle it.
Why can't you just dry clean the clothes?http://en.wikipedia.org/wiki/Dry_cleaningYou could recycle the tetrachloroethylene by heating it to 121 C, boiling it out of the waste from the clothes.
http://www.jemai.or.jp/english/dfe/pdf/19_8.pdfUse an ultrasonic machine to clean the clothes, then filter the water, then recirculate air across the clothes and condense the water out of them to be reused.
Not an expert on this but would ultrasonic cleaning of items work ?PhillUK