Members Can Post Anonymously On This Site
Space Telescope Science Institute Gets New Director
-
Similar Topics
-
-
-
By NASA
4 min read
Unearthly Plumbing Required for Plant Watering in Space
NASA is demonstrating new microgravity fluids technologies to enable advanced “no-moving-parts” plant-watering methods aboard spacecraft.
Boeing Astronauts Sunita Williams and Butch Wilmore during operations of Plant Water Management-6 (PWM-6) aboard the International Space Station. Image: NASA Crop production in microgravity will be important to provide whole food nutrition, dietary variety, and psychological benefits to astronauts exploring deep space. Unfortunately, even the simplest terrestrial plant watering methods face significant challenges when applied aboard spacecraft due to rogue bubbles, ingested gases, ejected droplets, and myriad unstable liquid jets, rivulets, and interface configurations that arise in microgravity environments.
In the weightlessness of space, bubbles do not rise, and droplets do not fall, resulting in a plethora of unearthly fluid flow challenges. To tackle such complex dynamics, NASA initiated a series of Plant Water Management (PWM) experiments to test capillary hydroponics aboard the International Space Station in 2021. The series of experiments continue to this day, opening the door not only to supporting our astronauts in space with the possibility of fresh vegetables, but also to address a host of challenges in space, such as liquid fuel management, Heating, Ventilation, and Air Conditioning (HVAC), and even urine collection.
The latest PWM hardware (PWM-5 and -6) involves three test units, each consisting of a variable-speed pump, tubing harness, assorted valves and syringes, and either one serial or two parallel hydroponic channels. This latest setup enables a wider range of parameters to be tested—e.g., gas and liquid flow rates, fill levels, inlet/outlet configurations, new bubble separation methods, serial and parallel flows, and new plant root types, numbers, and orders.
Most of the PWM equipment shipped to the space station consists of 3-D printed, flight-certified materials. The crew assembles the various system configurations on a workbench in the open cabin of the station and then executes the experiments, including routine communication with the PWM research team on the ground. All the quantitative data is collected via a single high-definition video camera.
The PWM hardware and procedures are designed to incrementally test the system’s capabilities for hydroponic and ebb and flow, and to repeatedly demonstrate priming, draining, serial/parallel channel operation, passive bubble management, limits of operation, stability during perturbations, start-up, shut-down, and myriad clean plant-insertion, saturation, stable flow, and plant-removal steps.
PWM-5 Hydroponic channel flow on the International Space Station with: (1) packed synthetic plant root model in passive bubble separating hydroponic channel, (2) passive aerator, (3) passive fluid reservoirs for water and nutrient solution balance, (4) passive bubble separator, (5) passive water trap, and (6) passive gas/bubble diverter. The flow is left to right across the channel and the aerated oxygenating bubbly flow is fully separated (no bubbles) by the bubble separator returning only liquid to the ‘root zone.’ The water trap, bubble diverter, root bundle and hydroponic channel dramatically increase the reliability of the plumbing by providing redundant passive bubble separating functions. Image courtesy of J. Moghbeli/NASA PWM-5 and -6 Root Models R1 – R4 from smallest to largest: perfectly wetting polymeric strands modelling Asian Mizuna. Image courtesy of IRPI LLC The recent results of the PWM-5 and -6 technology demonstrations aboard the space station have significantly advanced the technology used for passive plant watering in space. These quantitative demonstrations established hydroponic and ebb and flow watering processes as functions of serial and parallel channel fill levels, various types of engineered plant root models, and pump flow rates—including single-phase liquid flows and gas-liquid two-phase flows.
Critical PWM plumbing elements perform the role of passive gas-liquid separation (i.e., the elimination of bubbles from liquid and vice versa), which routinely occurs on Earth due to gravitational effects. The PWM-5 and -6 hardware in effect replaces the passive role of gravity with the passive roles of surface tension, wetting, and system geometry. In doing so, highly reliable “no-moving-parts” plumbing devices act to restore the illusive sense of up and down in space. For example,
hundreds of thousands of oxygenating bubbles generated by a passive aerator are 100% separated by the PWM bubble separator providing single-phase liquid flow to the hydroponic channel, 100% of the inadvertent liquid carry-over is captured in the passive water trap, and all of the bubbles reaching the bubble diverter are directed to the upper inlet of the hydroponic channel where they are driven ever-upward by the channel geometry, confined by the first plant root, and coalesce leaving the liquid flow as a third, redundant, 100% passive phase-separating mechanism. The demonstrated successes of PWM-5 and -6 offer a variety of ready plug-and-play solutions for effective plant watering in low- and variable-gravity environments, despite the challenging wetting properties of the water-based nutrient solutions used to water plants. Though a variety of root models are demonstrated by PWM-5 and -6, the remaining unknown is the role that real growing plants will play in such systems. Acquiring such knowledge may only be a matter of time.
100% Passive bubbly flow separations in microgravity demonstrated for PWM ‘devices’: a. bubble separator, b. bubble diverter, c. hydroponic channel and root model, and d. water trap. Liquid flows denoted by red arrows, air flows denoted by white arrows. Images courtesy of NASA Project Lead: Dr. Mark Weislogel, IRPI LLC
Sponsoring Organization: Biological and Physical Sciences Division
Share
Details
Last Updated May 20, 2025 Related Terms
Science-enabling Technology Biological & Physical Sciences International Space Station (ISS) Technology Highlights Explore More
5 min read NASA’s NICER Maps Debris From Recurring Cosmic Crashes
Article
2 weeks ago
6 min read Quantum Sensing via Matter-Wave Interferometry Aboard the International Space Station
Article
2 weeks ago
4 min read Entrepreneurs Challenge Winner PRISM is Using AI to Enable Insights from Geospatial Data
Article
4 weeks ago
View the full article
-
By NASA
This article is for students grades 5-8.
The International Space Station is a large spacecraft in orbit around Earth. It serves as a home where crews of astronauts and cosmonauts live. The space station is also a unique science laboratory. Several nations worked together to build and use the space station. The space station is made of parts that were assembled in space by astronauts. It orbits Earth at an average altitude of approximately 250 miles. It travels at 17,500 mph. This means it orbits Earth every 90 minutes. NASA is using the space station to learn more about living and working in space. These lessons will make it possible to send humans farther into space than ever before.
How Old Is the Space Station?
The first piece of the International Space Station was launched in November 1998. A Russian rocket launched the Russian Zarya (zar EE uh) control module. About two weeks later, the space shuttle Endeavour met Zarya in orbit. The space shuttle was carrying the U.S. Unity node. The crew attached the Unity node to Zarya.
More pieces were added over the next two years before the station was ready for people to live there. The first crew arrived on Nov. 2, 2000. People have lived on the space station ever since. More pieces have been added over time. NASA and its partners from around the world completed construction of the space station in 2011.
______________________________________________________________________
Words to Know
Airlock: an air-tight chamber that can be pressurized and depressurized to allow access between spaces with different air pressure.
Microgravity: a condition, especially in space orbit, where the force of gravity is so weak that weightlessness occurs.
Module: an individual, self-contained segment of a spacecraft that is designed to perform a particular task.
Truss: a structural frame based on the strong structural shape of the triangle; functions as a beam to support and connect various components.
______________________________________________________________________
How Big Is the Space Station?
The space station has the volume of a six-bedroom house with six sleeping quarters, two bathrooms, a gym, and a 360-degree view bay window. It is able to support a crew of seven people, plus visitors. On Earth, the space station would weigh almost one million pounds. Measured from the edges of its solar arrays, the station covers the area of a football field including the end zones. It includes laboratory modules from the United States, Russia, Japan, and Europe.
What Are the Parts of the Space Station?
In addition to the laboratories where astronauts conduct science research, the space station has many other parts. The first Russian modules included basic systems needed for the space station to function. They also provided living areas for crew members. Modules called “nodes” connect parts of the station to each other.
Stretching out to the sides of the space station are the solar arrays. These arrays collect energy from the sun to provide electrical power. The arrays are connected to the station with a long truss. On the truss are radiators that control the space station’s temperature.
Robotic arms are mounted outside the space station. The robot arms were used to help build the space station. Those arms also can move astronauts around when they go on spacewalks outside. Other arms operate science experiments.
Astronauts can go on spacewalks through airlocks that open to the outside. Docking ports allow other spacecraft to connect to the space station. New crews and visitors arrive through the ports. Astronauts fly to the space station on SpaceX Dragon and Russian Soyuz spacecraft. Robotic spacecraft use the docking ports to deliver supplies
Why Is the Space Station Important?
The space station has made it possible for people to have an ongoing presence in space. Human beings have been living in space every day since the first crew arrived. The space station’s laboratories allow crew members to do research that could not be done anywhere else. This scientific research benefits people on Earth. Space research is even used in everyday life. The results are products called “spinoffs.” Scientists also study what happens to the body when people live in microgravity for a long time. NASA and its partners have learned how to keep a spacecraft working well. All of these lessons will be important for future space exploration.
NASA currently is working on a plan to explore other worlds. The space station is one of the first steps. NASA will use lessons learned on the space station to prepare for human missions that reach farther into space than ever before.
Career Corner
Are you interested in a career that is related to living and working in space? Many different types of jobs make the space station a success. Here are a few examples:
Astronaut: These explorers come from a wide variety of backgrounds including military service, the medical field, science research, and engineering design. Astronauts must have skills in leadership, teamwork, and communications. They spend two years training before they are eligible to be assigned to spaceflight missions.
Microgravity Plant Scientist: These scientists study ways to grow plants in the microgravity environment of space. Growing plants on future space missions could provide food and oxygen. Plant scientists design experiments to be conducted by astronauts on the space station. These test new techniques for maximizing plant growth.
Fitness Trainer: Spending months on the space station takes a toll on astronauts’ bodies. Fitness trainers work with astronauts before, during, and after their space station missions to help keep them strong and healthy. This includes creating workout plans for while they’re living and working in space.
More About the International Space Station
International Space Station Home Page
Spot the Station
Video: #AskNASA What Is the International Space Station?
Read What Is the International Space Station? (Grades K-4)
Explore More For Students Grades 5-8
View the full article
-
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.