NASA's Lunar Loo Challenge


Creative Ideas

Location (s):

  • Online
  • United States of America


Help astronauts go back to the Moon in 2024! NASA seeks new designs for a toilet that will work both in microgravity and lunar gravity.


We are going back to the Moon.  

Artemis is NASA’s program to land the first woman and the next man on the Moon by 2024. Humanity is going back to the Moon to establish a presence that will enable eventual crewed journeys to Mars. As we prepare for our return to the Moon, innumerable activities to equip, shelter, and otherwise support future astronauts are underway. These astronauts will be eating and drinking, and subsequently urinating and defecating in microgravity and lunar gravity. While astronauts are in the cabin and out of their spacesuits, they will need a toilet that has all the same capabilities as ones here on Earth.  

NASA is calling on the global community for their novel design concepts for compact toilets that can operate in both microgravity and lunar gravity. These designs may be adapted for use in the Artemis lunar landers that take us back to the Moon. Although space toilets already exist and are in use (at the International Space Station, for example), they are designed for microgravity only. NASA is looking for a next-generation device that is smaller, more efficient, and capable of working in both microgravity and lunar gravity. Getting back to the Moon by 2024 is an ambitious goal, and NASA is already working on approaches to miniaturize and streamline the existing toilets. But they are also inviting ideas from the global community, knowing that they will approach the problem with a mindset different from traditional aerospace engineering. This challenge hopes to attract radically new and different approaches to the problem of human waste capture and containment.


With the Artemis program, NASA will land the first woman and the next man on the Moon in 2024, and the goal is to do this in a way that uses less mass, occupies less volume, is more energy efficient, and has streamlined processes. This massive effort is able to stay on track thanks to intensive collaboration between NASA and its commercial partners. These partners are designing and developing different elements that are part of the overall program, including lunar landers and rovers. Toilets will be integrated into landers developed by commercial partners. Due to the parallel development of components, the exact dimensions and performance specifications of lunar toilets are still unknown. Nonetheless, there are general specifications and constraints for these toilets, and they are discussed below. Designing and developing new lunar toilets may not be as exciting or intriguing as developing tools to support the exploration of the lunar surface, but the need is just as important.

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.

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

Opportunity is About:


Candidates should be from:

Description of Ideal Candidate:

We want to encourage the next generation of space explorers, engineers, and scientists, and we know that students may think about this design problem without the same constraints as adults. So in addition to the main Technical category, this challenge will have a Junior category. To submit to the Junior category, you must be less than 18.  


Deadline: August 17, 2020

Cost/funding for participants:


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)
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