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ISS Research Design Challenge


CELERE is not being offered in 2020 because it was discovered that the CAD software upon which it is based is no longer free but now requires a significant subscription fee. Efforts are underway to revise CELERE using open source CAD software for the 2020-2021 school year.


Capillary Effects on Liquids Exploratory Research Experiments

  • The NASA Facebook page for CELERE


The curiosity-driven design challenge is a joint educational program of NASA and Portland State University (PSU) enabling students to participate in microgravity research on capillary action related to that conducted on the International Space Station (ISS). Students create their own experiments using Computer-Aided Design (CAD) with a provided template. Experiment proposals, which each consist of a single CAD drawing and short entry form, are e-mailed to NASA. The test cells are then manufactured using the drawings and a computer-controlled laser cutter. Each experiment is conducted in PSU’s Dryden Drop Tower, in which it falls 22 meters (73 feet) and experiences 2.1 seconds of apparent near weightlessness, i.e., microgravity. Video and still images from each drop are provided online for student analysis and the reporting of results, for example in a science fair or class presentation. The image below shows an example experiment (from Columbus, Georgia) during the middle of the drop, where the oil’s upward motion is clearly slowed by the scalloped wall in the right channel.


The design challenge is for students in grades 8-12, who may participate as individuals or in teams of any size. Teams may include younger students as long as there is at least one team member in grades 8-12, where this can facilitate the participation of 4-H clubs, Scout troops, etc. The program is limited to students from the United States. It is open to all fifty states, the District of Columbia, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands, and the U.S. Virgin Islands. Students in other countries – even if U.S. citizens – are ineligible, with the exception of those attending DODEA schools for the children of U.S. military personnel. Youth are free to get help from adults, for example in creating their CAD drawing.


Proposals must be submitted to by 1 March 2021, where it is expected that the selected experiments will be conducted during that month. Written reports on the results are due to by 1 May 2021. Some participants will be invited to present their results at a technical conference in the fall of 2021; see the next page.


Students participate remotely, without travelling to PSU or NASA. But they can interact with NASA by e-mail or teleconferencing. However, some participants will be invited to present on their results at a nation-wide conference; see the next page.


The design challenge enables students to learn about computer technology and participate in research related to space station science, both of which can inspire the pursuit of STEM careers. Boy Scouts could potentially use the CAD drawing toward completion of the Drafting merit badge. And selection in a nation-wide NASA design challenge is an accomplishment worth noting on college applications!


Some CELERE participants – selected based on their experiment design, data analysis, and written report – will be invited to present their results in a student poster session at the 2020 meeting of the American Society for Gravitational and Space Research (ASGSR). The student day will be a Saturday in October or November, where the dates and location for the 2021 conference have yet to be announced. It is expected that financial support will be provided to help invited students travel to the meeting and present their results.


There is no cost to participate in CELERE other than the optional conference travel.


Capillary action occurs when liquid molecules are more attracted to a surface than to each other. In paper towels, the water molecules move along tiny fibers. In plants (like celery), the water moves upward through narrow tubes called capillaries.  Capillary action occurs on Earth, but can be difficult to observe – except with small capillaries – because of gravity.  But when experiments fall in a drop tower, capillary effects are easy to see and study!


When an experiment falls down PSU’s Dryden Drop Tower (shown on the right), it behaves as if gravity has nearly vanished – of course neglecting the fall!  Our sensation of gravity and weight comes from a resistance to its pull, for example because of the floor holding us up.  While freely falling, we feel weightless and that is the basis for many amusement park rides.  This works because all objects fall at the same acceleration unless acted upon by another force.  As one result, the astronauts and the ISS fall together (around the Earth) such that the astronauts float within the space station.  This happens even though the space station is so close to the Earth that the gravity is only about 10% less than that on the planet’s surface.


Prof. Mark Weislogel of the Portland State University (PSU) is a world leader in the study of capillary action and with NASA support has  been a researcher on the following International Space Station experiments: Capillary Beverage, Capillary Channel Flow, Capillary Flow Experiment 1 and 2 (depicted below with astronaut Sunita Williams), Capillary Structures, Non-Newtonian Fluids in Microgravity, Plant Water Management, and the Surface Tension Containment Experiment 2.

Astronaut Sunita Williams


See the website* or e-mail the challenge staff at

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