NASA's Human Landing System (HLS) Program


NASA's Lunar Loo Challenge

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.

This challenge is closed


This challenge is closed



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.

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.  

This Lunar Toilet Challenge has a total prize purse of $35,000 that will be shared among the teams submitting the top three designs in the Technical category.  The top three participants in the Junior category will each receive public recognition and an item of official NASA-logoed merchandise.



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


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 deadlineAugust 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. 


Technical Judging Criteria



Overall Weight

Proposal quality

Quality of proposal: clear, concise writing;  thoughtful and complete explanations of how the proposed toilet design concept meets the specifications listed; accompanying CAD file (or other file format) is clear and complete.


Capabilities - usage

Overall technical feasibility of the proposal toilet design.

Compatible for use by both female and male crew members.

How well does the design address issues like ease of use, odor control, noise, and turnaround time.

Likelihood that it will function in both microgravity and lunar gravity when prototyped.

How easy will it be to adapt the design for integration into a lunar rover.


Capabilities - capacity

Likelihood that it can successfully meet the performance specifications when prototyped, capturing: 

  • Urine (and stabilizing it),
  • Feces (accommodating simultaneous urination and defecation)
  • Diarrhea,
  • Vomit,
  • Menses

Likelihood that it can accommodate the needs of 2 crew members for 14 days.

Defines how often the collections system must be replaced or disposed of in the mission.


Technical maturity

The likelihood that proposed toilet design can be developed and integrated in the next 2-3 years.

Quality of the explanation and supporting evidence for why a solution is designated at a particular maturity level.



Confidence that proposed design will minimize the crew handling of crew waste during maintenance or system use in all mission environments, and will not expose crew to vacuum in the event of a system failure.



Novelty or creativity of proposed approach.

Elegance of design.

Describe how the innovation overcomes limitations and constraints of existing technologies or commercial products.


Your Submission

Questions marked with an asterisk (*) are required. Character limits include spaces.

  1. Please enter your full name and email address. If submitting as a team, please list the full name and email address of each team member. Tell us a little about your background. * (2000 characters)
  2. Please confirm you are 18 or older. If you are under 18, please submit to the Junior Category (www.herox.comm/LunarLooJr) or have an adult complete this application on your behalf * (3000 characters)
  3. Please upload an image of your design. *
  4. Please discuss in detail how your design will: (i) work in both microgravity and lunar gravity, (ii) accommodate female and male crew, (iii) be easy to use and maintain, with low noise, low odor, and fast turnaround time, (iv) allow for transfer of collected waste to storage or external vehicle disposal (6000 characters)
  5. Please discuss in detail how your design will: (i) capture and contain urine, feces, vomit, diarrhea, and menses, (ii) Stabilize urine, (iii) accommodate simultaneous urination and defecation, (iv) accommodate the needs of 2 crew members for 14 days, (v) accommodates the use of toilet hygiene products, (vi) clears previous waste content prior to next use, (vii) defines how often the collections system must be replaced or disposed of in the mission  (6000 characters)
  6. Please discuss the safety measures in place to ensure that during nominal use or in the event of a system failure: (i) crew handling of waste materials during maintenance or system use is minimized, (ii) crew members are not exposed to vacuum  (5000 characters)
  7. Please discuss the technical maturity of your proposed toilet design. What TRL would you assign it? Please provide a supporting rationale and/or evidence for this rating. Why do you believe this could be developed and integrated into a lunar rover in the next 2-3 years?  (5000 characters)
  8. Please upload your design files and any supporting documentation here. (pdf, doc, docx)

Rules - Technical

Participation Eligibility:

The Prize is open to anyone age 18 or older participating as an individual or as a team. Individual competitors and teams may originate from any country, as long as United States federal sanctions do not prohibit participation (see: If you are a NASA employee, a Government contractor, or employed by a Government Contractor, your participation in this challenge may be restricted.

Submissions must be made in English. All challenge-related communication will be in English.

No specific qualifications or expertise in the field of waste management  is required. NASA encourages outside individuals and non-expert teams to compete and propose new solutions.

To be eligible to compete, you must comply with all the terms of the challenge as defined in the Challenge-Specific Agreement.

Intellectual Property

Innovators who are awarded a prize for their submission must agree to grant NASA a royalty free, non-exclusive, irrevocable, world-wide license in all Intellectual Property demonstrated by the winning/awarded submissions. See the Challenge-Specific Agreement for complete details.

Registration and Submissions:

Submissions must be made online (only), via upload to the website, on or before August 17th , 2020, at 5:00 pm ET. No late submissions will be accepted.

Selection of Winners:

Based on the winning criteria, prizes will be awarded per the weighted Judging Criteria section above.

Judging Panel:

The determination of the winners will be made by HeroX based on evaluation by relevant NASA specialists.

Additional Information

  • By participating in the challenge, each competitor agrees to submit only their original idea. Any indication of "copying" amongst competitors is grounds for disqualification.
  • All applications will go through a process of due diligence; any application found to be misrepresentative, plagiarized, or sharing an idea that is not their own will be automatically disqualified.
  • All ineligible applicants will be automatically removed from the competition with no recourse or reimbursement.
  • No purchase or payment of any kind is necessary to enter or win the competition.
  • Void wherever restricted or prohibited by law.

Challenge Updates

Ready for your next challenge?

Nov. 10, 2020, 11:35 a.m. PST by Liz Treadwell

NASA Tournament Lab has two other challenges currently running on HeroX that you don't want to miss out on! Click the hyperlinked challenge title to check them out:

NASA's Lunar Delivery Challenge



Honey, I Shrunk the NASA Payload, The Sequel


Recording: Meet the Winners of the Lunar Loo Challenge

Oct. 24, 2020, 10:51 a.m. PDT by Kyla Jeffrey

Thank you to everyone that tuned in to our "Meet the Winners" Webinar on Thursday! If you were unable to join the webinar, you can watch the recording below to meet the winners, learn more about their solutions, and how they developed them. 

In order to respect any intellectual property contained within the winning submissions, we will not be releasing them to the public. The recording of the webinar is the best place to learn more about the winning entries. 

While we are only able to award three winners, we would like to commend and recognize the over 2,000 other submissions that were received. The quality and caliber of the entries submitted is impressive. Please note that additional rankings or judges' scores will not be released.

Congratulations again to our winners and to everyone who participated in NASA's Lunar Loo Challenge!

Meet the Lunar Loo Winners!

Oct. 22, 2020, 6:10 a.m. PDT by Liz Treadwell

After multiple rounds of rigorous judging, we are excited to share the winners of the Lunar Loo Challenge - Technical Category!

At the submission deadline, we had received over 2,000 submissions from individuals and teams across the globe. There were many innovative designs and approaches to solving our toilet challenge that made it difficult for our judging panel to select the top 3 winners. Following much discussion and deliberation, here are the submissions that will be awarded the cash prizes:

  1. Boone Davidson's team, THRONE (Translunar Hypercritical Repository 1) - $20,000 award
  2. Thatcher Cardon's team, Individualized Collapsible Astronaut Toilet (ICAT) - $10,000 award
  3. Franziska Wülker, Centrifugal Lunar Toilet by Duravit AG - $5,000 award

NASA wanted to highlight a couple of honorable mentions as well:

Congratulations to the winners! NASA will be discussing what will happen with their designs during our webinar today.

Also, we would like to take this moment to send a sincere thank you to everyone who participated in this challenge. While only 3 winners were awarded, the team was very impressed with many of the proposals that were reviewed. We encourage you to keep innovating and solving problems such as these in other crowdsourcing opportunities.

We look forward to highlighting these winners further and seeing you all at the winners’ webinar in a few hours!

Webinar Reminder + Winner Announcement Update

Oct. 20, 2020, 1:32 p.m. PDT by Liz Treadwell

Hello Lunar Loo community!

Don't forget to join us on October 22nd @ 9am PDT to meet the winners of the Lunar Loo Main Challenge! You can register your attendance here.

Another important update: NASA is excited to promote the winners announcement through their channels and for this reason we'll have to delay the announcement until the following day. Winners will now be published October 22nd @ 6am PDT. You can view the exact date and time for your location in the Timeline here

We understand everyone is eagerly awaiting the results so we appreciate your patience!

Register now for the Lunar Loo Challenge - Technical Category Winner Webinar!

Oct. 16, 2020, 10 a.m. PDT by Liz Treadwell

We know you’re excited to see who the winners are in the Lunar Loo Challenge, and we want to give you the opportunity to hear from them directly when we host the winners’ webinar on October 22nd!

You’ll get to learn more about the winning entries, how they were developed and the teams who submitted them. 

The discussion will be moderated by HeroX's Kal Sahota and include panelists:

  • Michael Interbartolo, NASA Human Lunar Lander Crew Module SE&I Team
  • Steve Rader, NASA Tournament Lab
  • Imelda Stambaugh, NASA Human Lunar Lander Crew System Toilet Lead
  • Christian Cotichini, HeroX CEO
  • The challenge winners
  • A special guest appearance!

Save your virtual seat at the webinar by registering here. Make sure to register early since space is limited.

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