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NASA Challenge: Spacecraft Docking Adapter with a Flexible but Load-Bearing Floor

NASA is seeking to challenge the GrabCAD Community to design a flexible, but load-bearing floor for use in both microgravity and gravity as part of a docking system that can articulate to dock elements that are not perfectly aligned.

The Multi-Gravity Active-Active Mating Adapter (MGAAMA) is a generic docking system intended to join habitable spacecraft elements in both gravity and microgravity environments. A unique feature of this docking system is that each active end is connected to a central bulkhead via Stewart platforms, such that it is capable of 15-degree offsets in roll, pitch, and yaw between docked elements. This enables not only docking on uneven terrain, but also enables multi-element architectures to follow flexible paths such as around obstacles or even to form a circular arrangement, such as a rotating spacecraft intended to produce artificial gravity. However, this flexibility complicates the floor, which in a natural or artificial gravity environment will need to be load bearing, while also avoiding interference with the Stewart platform actuators. This challenge is to design a floor system that can be contained within the MGAAMA. It must articulate or flex as the MGAAMA adjusts to different angles but must be rigid and load bearing to support suited crew transfer in gravity environments up to full Earth-equivalent gravity.

A successful outcome is a flexible, load-bearing system as measured by the following:

1. CAD model of the flooring system, including any associated linked models (see requirements below).

2. Excel format table listing for each component item the name, quantity, rough dimensions, volume, suggested material (e.g., aluminum, plastic, fabric, etc.), estimated mass, and any associated operating parameters (e.g., power if an electrically powered item).

3. Report in Word format describing the overall flooring system, each component item, and how they should be used in the Multi-Gravity Active-Active Mating Adapter. There are no page length guidelines – it should be sufficient to describe your concept. Include illustrations.


The Common Habitat is a large, long-duration habitat being explored as part of a feasibility study (not an active NASA program) that uses an SLS core stage liquid oxygen (LOX) tank as its primary structure. Measuring 8.4 meters in diameter and 15 meters in length, it is manufactured as a habitat and launched as such into
space. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at
a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. The MGAAMA is used to dock the Common Habitat to logistics modules, pressurized rovers, and an airlock.

An overview of the MGAAMA is found in the paper, A Multi-Gravity Docking and Utilities Transfer System for a Common Habitat Architecture -https://ntrs.nasa.gov/citations/20210020833.

Additional Background:
• Common Habitat Base Camp for Moon and Mars Surface Operations - https://ntrs.nasa.gov/citations/20210020956
• A Common Habitat Deep Space Exploration Vehicle for Transit and Orbital Operations -https://ntrs.nasa.gov/citations/20210021084
• A Safe Haven Concept for the Common Habitat in Moon, Mars, and Transit Environments -https://ntrs.nasa.gov/citations/20210020788
• A Multi-Functional, Two-Chamber Airlock Node for a Common Habitat Architecture -https://ntrs.nasa.gov/citations/20210020897
• Internal Architecture of the Common Habitat -https://ntrs.nasa.gov/citations/20210021782
• Stowage Assessment of the Common Habitat Baseline Variants - https://ntrs.nasa.gov/citations/20205007257

For purposes of this challenge, all hatches shall be assumed to have an opening described by a rounded rectangle, 60 inches in height by 40 inches in width, with a
radius of curvature of 5.9 inches at each corner. All vertical passages between decks have the same size openings – anything that can pass through a hatch on one deck can be transported through a vertical passage to another deck. Vertical passages are generally not adjacent to a wall but are instead near or at the center of the deck. Assume a habitat with 3, 4, or 6 decks and a floor-to-floor distance of 2.5 meters. (Number of decks is a trade study currently in progress and the solution must work regardless of the habitat height ultimately selected.)

Ideas that should be excluded:
● Exclude swapping out of the hardware. (e.g., flat panels of various sizes and pitch angles stored in another module that is positioned as needed). Any solution not common to all gravity environments and all potential orientations of the MGAAMA are to be excluded. Any solution that requires the onboard crew to reconfigure is to be excluded.
● Avoid solutions that are difficult or cumbersome to operate. Imagine having to use this system in your home.
● Avoid solutions that could cause injury or leave crew members trapped or cut off from one another.


  • Judging Factors

    1. Successful designs will meet submission requirements
    2. Short description of flexible flooring system and each component item and how they
    should be used in the MGAAMA. The description should be of sufficient detail to describe your concept. Include both illustrations and text.
    3. Is the design real? Can the design work? Can it actually be created?
    4. Meets dimension requirements
    **5. If an engineer can provide a simulation of the system, that is a plus but is not

  • 1, The system shall require no reconfiguration or alteration to operate in 0g, 1/6g, 3/8g, and 1g.
    2. The flooring system must support the load of two EVA-suited crew members in 1g. (Assume 500 kg as a target mass limit.)
    3. The flooring system must be wide enough to facilitate walking by an EVA-suited crew member.
    4. The flooring system must accommodate MGAAMA articulation up to 15 degrees in roll, pitch, and yaw. A stretch goal is to accommodate 15 degrees from each Stewart platform, resulting in a total 30-degree articulation.
    5. The flooring system shall not decrease its flooring system-to-ceiling height regardless of MGAAMA articulation in roll, pitch, and yaw.
    6. The flooring system may not require human intervention to articulate along with the MGAAMA.
    7. The flooring system shall be positioned 16 inches beneath the lower lip of the hatch opening.
    8. The flooring system shall not preclude the use of wheeled systems to transport cargo through the MGAAMA in gravity environments.
    9. The mass for the flooring system must be less than 100 kg.
    10. The flooring system may not constrain the motion of the Stewart platform actuators.
    11. The flooring system may not prevent the retraction of all Stewart platform actuators in parallel (thereby compressing the MGAAMA length).
    12. The flooring system shall be described in a written paper utilizing both text and visuals. Animations are not required but may be included. A CAD model of the flooring system must be provided. CAD files must be provided in a format that can be opened by Rhino 7 or will not be considered for evaluation.
    13. Models will be reviewed using Rhino 7. It is therefore strongly preferred that CAD models be prepared in Rhino using NURBS and subject to the following. All components should use Rhino block instancing with linked and embedded files. May involve conversions of models obtained in other CAD formats into Rhino and/or re-modeling of Rhino meshes as NURBS. Models prepared and submitted in other CAD formats will still be fully considered, provided they can be opened using Rhino. (If not saved as a .3dm file it is strongly recommended to include a copy saved as a STEP file.)

  • The “Download specification” contains a zip file of three simplistic CAD models that may help you in your efforts, but their use is optional.

    1. The file “DOC Simple 4x6 to 4x6 MGAAMA Shell.stp” is the notional Multi-Gravity Active-Active Mating Adapter. This is a very preliminary version of the docking adapter that will contain the floor you are designing. The double Stewart Platform in the MGAAMA is notional and almost certainly not the final design. You may discover that it is in the way of your floor. Do not let it affect your design. Because it will change, NASA is not concerned if there are collisions between your floor system and the Stewart actuators. The MGAMMA will, however, give you an idea of how your flooring system will be used.

    2.The file “LOG_MPLM_Shell_with_Hatches.stp” is a simple model of a Logistics Module. These units contain supplies that will be used by the crew and in an emergency can also function as a shelter for several weeks. This model is empty (nothing is inside) but it gives you a sense of where the docking interface to the MGAAMA is located.

    3.The file “Two-Chamber Airlock.stp” is a simple model of a combination airlock and node that is used in the Common Habitat Architecture. One chamber can be depressurized for EVA while the other chamber remains pressurized to support suit maintenance, supplies storage, and docking to other modules.
    An optional demonstration of your flooring system could be to show it inside the MGAAMA with the MGAAMA docked to Logistics Modules and Airlocks. One example might be a docking over uneven surface terrain, perhaps forming a circular base configuration. Another example might be forming a rotating spacecraft for artificial gravity. Showing your floor system supporting different MGAAMAs with varying degree offsets in roll, pitch, and yaw will help demonstrate an effective solution.

Download specification



    If you think an entry may infringe on existing copyrighted materials, please email challenges@grabcad.com.

    By entering the Challenge you:

      1) Accept the official GrabCAD Challenges Terms & Conditions.
      2) Agree to be bound by the decisions of the judges (Jury).
      3) Warrant that you are eligible to participate.
      4) Warrant that the submission is your original work. Warrant, to the best of your knowledge, your work is not, and has not been in production or otherwise previously published or exhibited.
      5) Warrant neither the work nor its use infringes the intellectual property rights (whether a patent, utility model, functional design right, aesthetic design right, trademark, copyright or any other intellectual property right) of any other person.
      6) Warrant participation shall not constitute employment, assignment or offer of employment or assignment.
      7) Are not entitled to any compensation or reimbursement for any costs.
      8) Agree the Sponsor and GrabCAD have the right to promote all entries.

  • Submitting an Entry

    Only entries uploaded to GrabCAD through the "Submit entry" button on this Challenge page will be considered an entry. Only public entries are eligible. We encourage teams to use GrabCAD Workbench for developing their entries. Entries are automatically given the tag "NASASPACECRAFTDOCKING"; when uploading to GrabCAD. Please do not edit or delete this tag. Only entries with valid tag will participate in the Challenge.


    The sum of the Awards is the total gross amount of the reward. The awarded participant is solely liable for the payment of all taxes, duties, and other similar measures if imposed on the reward pursuant to the legislation of the country of his/her residence, domicile, citizenship, workplace, or any other criterion of similar nature. Only 1 award per person. Prizes may not be transferred or exchanged. All winners will be contacted by the GrabCAD staff to get their contact information and any other information needed to get the prize to them. Payment of cash awards is made through Checks mailed to the Winners. All team awards will be transferred to the member who entered the Challenge. Vouchers will be provided in the form of Stratasys Direct Manufacturing promo codes.

    We will release the finalists before the announcement of the winners to give the Community an opportunity to share their favorites in the comments, discuss concerns, and allow time for any testing or analysis by the Jury. The Jury will take the feedback into consideration when picking the winners.

    Winning designs will be chosen based on the Rules and Requirements schedule.

  • In order to be eligible for a prize solutions must originate from either the U.S. or a designated country (see definition of designated country at https://www.acquisition.gov/far/part-25#FAR_25_003), OR have been substantially transformed in the US or designated country prior to delivery pursuant to FAR 25.403(c).

  • Schedule

    This Challenge ends on September 7th, 2022 (23:59 EST.) Finalists will be announced on September 14th, 2022 and Winners will be announced on September 21st, 2022


$7000 in Total Prizes

$7000 in Total Prizes

First Place


Second Place


Third Place


Fourth Place


Fifth Place


About the jury?

Robert L. Howard,Jr., Ph.D. - Habitability Domain Lead

Scott Howe, Ph.D. - Systems Engineer / Space Architect

Dawn Martin, Ph.D., CPE - Flight Crew Equipment - Commercial Crew Program

Tanya Andrews - Human Factors and Integrated Logistics Engineering (HFILE) Team Lead

About NASA - Center for Design and Space Architecture (CDSA)

This challenge is sponsored by the Center for Design and Space Architecture (CDSA),
which is NASA Johnson Space Center’s design studio for human-centered design,
concept development, and rapid prototyping of human spaceflight architectures. The
CDSA team uses sketches, engineering analysis, CAD modeling, Virtual Reality, and
physical mockups to create options for human exploration of the inner solar system.


  • Carlos J. Veloso

    Carlos J. Veloso 14 days ago

    NASA is getting cheap, no prize.

    Carlos J. Veloso has uploaded 7 CAD models & has left 574 comments.
  • Francisco J. Erenas Rivas

    Francisco J. Erenas Rivas 14 days ago

    it is because of the world crisis.... :)

    Francisco J. Erenas Rivas has uploaded 41 CAD models & has left 85 comments.
  • Mercury3D (Tom Leighton)

    Mercury3D (Tom Leighton) 13 days ago

    What are the weight bearing requirements for the floor? Will the floor need to be compatible with wheeled devices (like a cargo dolly?..sorry, i mean space cargo dolly).

    Mercury3D (Tom Leighton) has uploaded 1 CAD models & has left 2 comments.
  • Vance Benton

    Vance Benton 13 days ago

    There is a prize, I will work with GradCAD to update

    Vance Benton has uploaded 0 CAD models & has left 1 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 13 days ago

    Good afternoon, Tom. The challenge was accidentally launched without the full requirements listing. That has been corrected and you may have noticed it by now but #2 in the technical requirements largely covers your question. The floor needs to hold 500 kg in Earth gravity. The flooring system does need to be compatible with wheeled devices. There's a paper coming out this fall where we will be talking about a wheeled system for transporting an incapacitated crew member, so you are right on target with your question. Unfortunately I can't show you any images of that before this competition is over. Don't worry about crossing the hatch threshold, though (the floor is always 16" below the bottom of the hatch - it's a whole other study that set that requirement and dealing with it is outside the scope of this challenge), but any wheeled cargo unit should be able to roll on the floor itself. You could imagine having as test subjects the Mars Pathfinder Sojourner rover joined by some fictional robots: R2D2 from Star Wars, Crichton from Buck Rogers in the 25th Century, and The Robot from the original Lost In Space. If all of these can handle your floor, you have a great solution. Great question! Please keep them coming and to everyone, thank you in advance for your creative ideas!

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Tim Khafizov

    Tim Khafizov 12 days ago

    1) What is the minimum area of a spacesuit boot and how close can astronauts stand to each other? This is necessary to calculate the critical loading of the floor structure.
    2) During the deployment of the gateway, where should the floor structure be located? (I did not see the requirements for the placement of the floor structure)

    Tim Khafizov has uploaded 0 CAD models & has left 5 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 12 days ago

    More good questions. (1) The lunar spacesuits are being designed by contractors today, but for a rough estimate, assume each spacesuit occupies a rough footprint of 1 meter wide by 0.78 meters deep. Assume a maximum individual boot size of roughly 0.39 meters long and 0.24 meters wide. (2) I assume you didn't mean to say Gateway - this isn't the Gateway space station. But I assume you mean where is the floor contained within the MGAAMA? The floor system should be a permanently deployed component of the MGAAMA. It should stretch from hatch opening to hatch opening, located 16 inches (0.406 meters) beneath the bottom of the hatch opening. (Each hatch opening is 40 inches wide by 60 inches tall - sorry to mix units, the study that defined hatch sizes was done in standard units while I'm generally designing in metric. Mixed units are the reality of the times.)

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Kaleb Wells

    Kaleb Wells 11 days ago

    Hello everyone,

    1) What is the required range of retraction and expansion between individual hatches?

    2) Is the floor system required to offset roll to maintain normality to gravity? My understanding is that in >0g all decks should already be normal to gravity so the MGAAMA would not need to roll in >0g.

    Kaleb Wells has uploaded 0 CAD models & has left 2 comments.
  • Kaleb Wells

    Kaleb Wells 11 days ago

    3) What axis are pitch and yaw measured from? Is it the internal axis of each hatch or the axis of another hatch?

    Kaleb Wells has uploaded 0 CAD models & has left 2 comments.
  • Tim Khafizov

    Tim Khafizov 11 days ago

    I formulated the second question incorrectly. I will try to rephrase: What is the requirement for the installation of the floor being developed (automatic during the installation of the Spacecraft Docking Adapter or manual)?

    Tim Khafizov has uploaded 0 CAD models & has left 5 comments.
  • Bobby Weber

    Bobby Weber 10 days ago

    The ring diameter shown around the hatch opening doesn’t appear to accommodate the floor offset of 16 inches - can you provide the ring diameter or is this a variable the we control for the specified placement of the floor? Thx

    Bobby Weber has uploaded 0 CAD models & has left 2 comments.
  • Marc Samarra

    Marc Samarra 9 days ago

    Same question as Bobby Weber before me. 16" below hatch threshold it's already outside the outter ring.
    Are we supposed to ignore the CAD file provided and design something theoretical?
    See dimension pic here: https://ibb.co/z4WW4PC

    Also, how wide must the flooring be? Same as hatch opening span? wider or narrower?

    Marc Samarra has uploaded 0 CAD models & has left 3 comments.
  • Bobby Weber

    Bobby Weber 9 days ago

    Unless there is an error with units (mm instead of inches?), the challenge requirements as written are unworkable. With stated floor placement there will not be any wheeled equipment rolling through the MGAAMA without lifting over the hatch lips and everything (and everyone) will be dancing over the Stewart struts. My apologies if this is just the simple error in units but otherwise a comprehensive rework of challenge requirements by the project originators is needed.

    Bobby Weber has uploaded 0 CAD models & has left 2 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 9 days ago

    Several people asked about the hatch-to-floor distance. I probably shouldn't have even brought it up because there is an issue in the current model. The current floor is 11.38 inches below the hatch, which is not the correct value. I decided to not redesign the entire MGAAMA until I had the floor system (and several other identified problems) solved. The floor should be hidden in your model, but don't worry if it displayed when you imported the STEP file. (This is not the only issue that needs to be corrected, but none of them directly impact this challenge.) You have three choices that are equally fine:

    Option 1, use the current floor height. Don't worry about the fact that the floor is in the wrong position.

    Option 2, scale up the MGAMMA model until the 11.38-inch distance is increased to 16.

    Option 3, as Marc suggested, ignore the CAD models completely and design a system that can be incorporated into a pressure vessel.

    I'm more concerned about the mechanics of how your floor is designed than its placement in a model that is useful for illustration but already requires redesign. Use the models if they help you, but their use is not required.

    In terms of floor width, there is no maximum, though I doubt any solution will exceed hatch width. A likely minimum is 24 inches. That being said, the floor width will eventually be scaled to fit the redesigned MGAAMA, so it would be best if the flooring system will work with floor widths that vary from 24 inches to 40 inches. If you design to only one width, 30 inches is a safe width to use.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 9 days ago

    Tim, if I understand your question correctly, the flooring system should be installed during manufacture, not in space. It should be launched in a fully-deployed and operational configuration. Note that the MGAAMA will be used in fully autonomous spacecraft docking and undocking. Crew should not be required for any activity associated with docking or undocking other than to open/close the hatch when they pass through a module.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Tim Khafizov

    Tim Khafizov 9 days ago

    Yes, you got it right. Thank you for your answers. I'll try to make it on time.

    Tim Khafizov has uploaded 0 CAD models & has left 5 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 9 days ago

    Robert, I'm not imposing any material restrictions, so you can use polypropylene.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 9 days ago

    Kaleb, for your question number 1:
    There are no range requirements. Do take into account that the hatch is 40 inches wide and will need to open into the MGAAMA passageway.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 9 days ago

    Kaleb, for your question number 2:
    Yes, the floor system must offset up to 15 degrees in each of three axes: roll, pitch, and yaw. Keep in mind that this same docking system will be used for both fixed and mobile elements on off-road terrain. For instance, you could have two rovers (with side-mounted docking ports) next to each other on uneven terrain. One rover might be pitched up while the other is pitched down. This would create a need for the MGAAMA to offset roll.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 9 days ago

    Kaleb, for your question number 3:
    Roll, pitch, and yaw should be measured from the center of the MGAAMA.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Lucas Martin Dublanc

    Lucas Martin Dublanc 8 days ago


    Lucas Martin Dublanc has uploaded 4 CAD models & has left 195 comments.
  • Germano Pecoraro Designer

    Germano Pecoraro Designer 8 days ago


    Germano Pecoraro Designer has uploaded 20 CAD models & has left 31 comments.
  • Oleg P.

    Oleg P. 8 days ago

    Ukraine is available?

    Oleg P. has uploaded 1 CAD models & has left 2 comments.
  • hamdi amine

    hamdi amine 7 days ago

    Tunisia ?

    hamdi amine has uploaded 10 CAD models & has left 5 comments.
  • Javodbek Dadajonov

    Javodbek Dadajonov 7 days ago


    Javodbek Dadajonov has uploaded 12 CAD models & has left 6 comments.
  • Bagoes Prawira N

    Bagoes Prawira N 6 days ago

    Bagoes Prawira N has uploaded 39 CAD models & has left 19 comments.
  • Aston Zhang

    Aston Zhang 5 days ago

    What is the range that the floor must expand and shrink to?

    Aston Zhang has uploaded 0 CAD models & has left 1 comments.
  • david surridge

    david surridge 5 days ago

    Is it expected that the floor remain parallel to the various hatch openings throughout the length of the MGAAMA? Based upon the functional description and requirements it seems this would imply it could take on a fairly substantial twist. Or is it expected that the floor remain relatively flat, but allow the MGAAMA to twist/yaw/roll around it? This would then mean the floor would not remain parallel to the hatch openings but perhaps be easier to walk on, roll equipment, etc.

    david surridge has uploaded 10 CAD models & has left 6 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 3 days ago

    Aston, you ask a good question that does not have a clear answer. It's not so much a requirement for a specific expansion or shrinkage of the floor as it is an accommodation of the articulation. The Stewart platform can be implemented in many different ways, which would change the length of the individual actuators. The simplest thing for you to do is to model the actuators in the MGAAMA CAD model and estimate the maximum retraction experienced by any one actuator to achieve a 15-degree articulation in roll, pitch, or yaw. Then calculate the reduction in floor length that would be experienced if all of the actuators retracted to that amount. Maximum floor length would follow the same process, but look at actuator extension instead of retraction.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Robert L. Howard, Jr., Ph.D.

    Robert L. Howard, Jr., Ph.D. 3 days ago

    David, the key is going to be protecting the floor to ceiling height so that you don't induce choke points where tall crew or tall objects cannot get through. Yes, there might be twist in the floor and/or MGAAMA. Both could be allowed.

    Robert L. Howard, Jr., Ph.D. has uploaded 0 CAD models & has left 41 comments.
  • Mercury3D (Tom Leighton)

    Mercury3D (Tom Leighton) 2 days ago

    I've rewritten this sentence a few times this is my best attempt at asking this hopefully it makes sense: When the openings are at a 15 degree roll to one another, the top of the floor should be parallel with the bottom of the hatch opening ? (i.e. the floor should be able to articulate a 15 degree roll, but not "twist". Correct?) You want the floor to be "Flat" at all times right?

    Mercury3D (Tom Leighton) has uploaded 1 CAD models & has left 2 comments.
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