Are you looking for a design? NASA’s Lunar Loo Challenge

Are you looking for a design? NASA’s Lunar Loo Challenge: Lunar toilet design concepts should allow astronauts to urinate and defecate in both microgravity and lunar gravity.  Microgravity is what is generally considered “zero-g” and is experienced as weightlessness.  The g-force is not actually zero in microgravity; it is just very small.   Lunar gravity is approximately one sixth of Earth’s gravity, so urine and feces will fall down. NASA is already looking at ways to make currently-used space toilets smaller, lighter, and functional in lunar gravity, so your ideas should not be based on current waste management technology.  To be ready for deployment in 2024, the timelines for development and integration work are quite tight.  Successful designs will probably have a Technology Readiness Level (TRL) of 3-5.  See the Resource Tab for more information about TRLs.

The process for using proposed toilet designs must be relatively straightforward.  Anything that is very time intensive or complicated to use will generally be less attractive to NASA.   Toilets will operate in a nominal spacecraft environment with an air pressure of 14.7 psia (sea level like on Earth) or 8.2 psia, and the toilet storage systems could experience 0 psia (vacuum) during Extra-Vehicular Activities (EVA).   Additionally, toilet designs should conserve water and help maintain a pristine environment inside the lander that is free of odors and other contaminants.  Complete solutions will be ones that can support a crew of two astronauts for 14 days, while controlling odor, accommodating different types of waste (urine, feces, vomit, diarrhea, menses), and different gender users (female and male). Additionally, toilet designs must be able to accommodate sick crew members dealing with vomiting and diarrhea.  Although the preferred method for capturing vomit will be emesis bags (“throw up” bags), bonus points will be awarded to designs that can capture vomit without requiring the crew member to put his/her head in the toilet.

NASA’s Lunar Loo Challenge

NASA's Lunar Loo Challenge

Toilet Design Specifications

The specifications listed below represent the maximum allowed values.  Proposed designs should at least meet them and will preferentially be lower than them.  The toilet design should:

  • Function in both microgravity and lunar gravity
  • Have a mass of less than 15 Kg in Earth’s gravity
  • Occupy a volume no greater than 0.12 m3
  • Consume less than 70 Watts of power
  • Operate with a noise level less than 60 decibels (no louder than an average bathroom fan)
  • Accommodate both female and male users
  • Accommodate users ranging from 58 to 77 inches tall and 107 to 290 lbs in weight

Toilet Performance Specifications

We are looking for a design that captures all the functionality of a toilet on Earth.  At a minimum, crew using lunar toilets should not be exposed to vacuum during use, and toilet designs should be able to:

  • Accommodate simultaneous urination and defecation
  • Collect up to 1 liter of urine per use, with an average of 6 uses per crew per day
  • Accommodate 500g of fecal matter per defecation, with an average of 2 uses per crew per day
  • Accommodate 500g of diarrhea per event
  • Accommodate an average of 114g of female menses, per crew per day
  • Stabilize urine to avoid the generation of gas and particulates
  • Accommodate crew use of toilet hygiene products, like toilet paper, wipes, and gloves
  • Be clear of previous user’s urine and feces in preparation for the next use
  • Allow for transfer of collected waste to storage  and/or provide for external vehicle disposal. Minimal Lander volume requires regularly minimizing waste storage or removing it from the vehicle
  • Allow for easy cleaning and maintenance, with 5 minute turnaround time or less between uses

Additionally, in the event of a system failure, the toilet designs will ensure that:

  • All waste materials collected remain safely stored
  • The crew is not exposed to urine, feces, or other collected materials
  • The crew is not exposed to vacuum


This challenge has two categories: Technical and Junior.  Submissions to both categories are due no later than 5pmET on August 17, 2020.  The winners for the Technical category will be announced on September 30, and the winners for the Junior category will be announced on October 20, 2020.

The Technical category has a total prize purse of $35,000 USD.  Participants must be at least 18 years old.  The authors of the three most compelling submissions in this category will each win:

  • A cash prize
  • An opportunity to talk directly with NASA engineers and possibly with an astronaut about the proposed toilet design
  • A private tour of the Johnson Space Center (travel to Houston is not included)

This challenge will also recognize the top three submissions from the Junior category, one per age group.  The authors of these three submissions will each receive: public recognition from NASA and from HeroX, a winner’s certificate, and an item of official NASA-logoed merchandise.  Additional “mystery” prizes may also be awarded to winners of the Junior category.  Such prizes could include a video call between the winner’s science class and an astronaut, or NASA-logoed specialty items (patches, pins, etc).  To submit to this category, you must be less than 18 years of age. Click here to submit to the Junior category.




First Place


Second Place


Third Place 



Ages 15-17


Public recognition,

Official NASA-logoed merchandise

Additional “mystery” prizes

Ages 11-14
Under 11



Open to submissions  June 25, 2020
Submission deadline August 17, 2020 @ 5pm ET
Judging and evaluation (Technical) August 18 – September 22, 2020
Winners Announced (Technical) September 30, 2020
Judging and evaluation (Junior) August 18 – October 13, 2020
Winners Announced (Junior)  October 20, 2020


How do I win?

To advance beyond the preliminary evaluation rounds, your submission must, at minimum:

  • Include a design concept as both a PDF file and a neutral 3D CAD file, such as:
    • STEP (.stp and .step)
    • Wavefront (.obj)
  • Thoughtfully discuss how your design meets the various specifications listed above and provide supporting sketches, calculations or analysis

Submissions that pass the preliminary evaluation rounds will be reviewed by NASA’s evaluation panel, and winners will be selected using the Judging Criteria listed below.


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