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2021 Drop Tower Challenge

Droplet Ejection


Teams of grade 9-12 students are challenged to design and build simple devices using capillary flow (only) to eject water droplets as far as possible while the devices fall down NASA’s 2.2 Second Drop Tower.

Example capillary devices ejecting silicone oil

Teams are only responsible for their capillary devices. NASA will provide the rest of the experimental hardware. After developing their concept(s), the youth prepare their proposal, consisting of conceptual drawing(s) and a short entry form, which is then e-mailed to  Note that this is different from a past challenge that used silicone oil as the test fluid.

If selected, the team prepares their capillary devices based on information provided on the challenge website.  The devices are then sent to NASA where they will fall 24 meters (79 feet) and experience 2.2 seconds of apparent near weightlessness, i.e., microgravity.  Video results will then be provided for student analysis and reporting.


This design challenge is for students in grades 9-12 from U.S. schools, including the fifty states, District of Columbia, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands, the U.S. Virgin Islands, and all DODEA schools (which are for children of U.S. military personnel).  With the exception of the DODEA schools, it is not open to participants outside of the United States regardless of citizenship.  Teams, which can be of any size, will be favored over individuals in selection.  Students may get help from adults, for example in building their experiment hardware.

An organization (e.g., school, science center, 4H club, Scout troop) may submit no more than four proposals, where it is envisioned that no more than two will be selected from a single organization.  Each student may belong to only one team, which may submit only one proposal.

Selection?asgsr logo

NASA anticipates selecting up to 20 teams to build objects to be tested at the Glenn Research Center in Cleveland, Ohio. After evaluation of the experimental results and teams’ reports, a small number of top-performing teams will be invited to present their results in a student poster session at the 2021 meeting of the American Society for Gravitational and Space Research (ASGSR).


2.2 Second Drop Tower
2.2 Second Drop Tower

Challenge participation is remote and participants do not travel to NASA for the testing.  But top-performing teams will be invited to present their results at the 2021 ASGSR meeting, which is to be held in Baltimore, Maryland.


There is no cost to participate in the challenge other than for the (1) preparation of the test objects, (2) shipment of the test objects to NASA, and (3) travel costs for those invited to present their results at the ASGSR meeting.  Regarding the latter, the ASGSR has often provided travel support of $500 each for invited non-local students who present their results at the conference.


Nov. 10, 2020           deadline for proposal
Mid-December          NASA announces teams selected for testing
Jan.-Feb. 2021          preparation of test objects
Feb. 15                        deadline for arrival of test objects at NASA
Feb.-March                testing in NASA’s 2.2 Second Drop Tower
April                            analysis and report writing
May 1                           deadline for written report
Mid-May                     NASA announces teams selected for ASGSR participation
Fall 2021                     annual ASGSR meeting (presumably in Oct. or Nov.)


The odds are very high that your team will be selected for testing.  Thus far, 100% of the proposing teams have been selected for participation in this series of problem-based drop tower challenges.  Participation in a nation-wide NASA challenge might be a good addition to college applications.



Answers can be found at  If that doesn’t suffice, email the challenge staff at

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