In 1984, NASA sent 12.5 million tomato seeds into orbit for nearly six years. After their return, 132,000 experiment kits were distributed across every US state and 30 countries

In 1984, NASA sent 12.5 million tomato seeds into orbit for nearly six years. After their return, 132,000 experiment kits were distributed across every US state and 30 countries, turning a NASA space experiment into a classroom science project. The seeds were part of SEEDS, or Space-Exposed Experiment Developed for Students. NASA worked with the George W. Park Seed Company on the project. The original plan was to keep the seeds in space for about one year. That plan changed after the Challenger disaster in 1986 stopped shuttle missions. The seeds remained aboard NASA's Long Duration Exposure Facility, or LDEF, for 69 months. When the satellite returned to Earth in January 1990, students were given the chance to compare the space seeds with seeds that had stayed on Earth.

How NASA's tomato seeds ended up in space?

The experiment began on April 6, 1984. The Space Shuttle Challenger launched the LDEF satellite into orbit during mission STS-41C. The satellite was designed to study how materials responded to long periods of exposure to the space environment. Park Seed supplied 12.5 million Rutgers California Supreme tomato seeds for the experiment. The seeds were selected because they had consistent germination characteristics.


The seeds were sealed in containers and attached to the satellite. They were not planted in space. Instead, they remained stored while the satellite travelled around Earth. The original mission called for the LDEF to remain in orbit for about one year. Scientists planned to retrieve it and examine the materials and biological samples. That schedule changed after the Challenger disaster in January 1986. The shuttle fleet was grounded, and the planned retrieval was delayed.

Why the seeds stayed in orbit for nearly six years?

The LDEF remained in low Earth orbit for 69 months. During that period, the tomato seeds were exposed to conditions that are different from those on Earth. The satellite completed more than 32,000 trips around Earth. The seeds experienced solar radiation, cosmic rays, changes in temperature and the conditions of orbital flight. The experiment therefore lasted much longer than planned. Scientists could not know in advance whether the long exposure would affect the seeds.

There were several questions surrounding the experiment:

• Would the seeds remain capable of germination?
• Would exposure affect their growth?
• Would radiation damage their viability?
• Would there be a measurable difference between the space seeds and seeds kept on Earth?
• The answers came after the LDEF was finally brought back.

The satellite returned in 1990

The LDEF was retrieved by Space Shuttle Columbia on January 20, 1990. The satellite had spent 69 months in orbit. The tomato seeds had therefore remained in space for almost six years rather than the planned one year. The return created the basis for the next stage of the project.

NASA and Park Seed used the recovered seeds in an education program. The project was called SEEDS, or Space-Exposed Experiment Developed for Students. The aim was not only to study the seeds. It was also to allow students to conduct the experiment themselves.

How students tested the space seeds?

About 132,000 experiment kits were distributed to schools and students. The kits reached every US state and 30 foreign countries, according to NASA material supplied for the program. Other accounts describe the US distribution as more than 40,000 schools across all 50 states.

Students from kindergarten through university took part. Estimates of total participation vary across accounts, with figures ranging from more than 3 million to about 4 million students. The basic method was simple. Students planted two groups of seeds.

One group contained the tomato seeds that had spent years in orbit. The second group contained matching control seeds. The control seeds had been stored on Earth under controlled conditions during the same period. This gave students a way to compare the two groups.

They could observe:

• Whether the seeds germinated
• How quickly germination occurred
• How the plants developed
• Differences in growth
• Other planting characteristics
• Students recorded their observations and results as part of the project.

What happened when the seeds were planted?

The results did not show a large difference between the two groups. The space-exposed tomato seeds recorded a germination rate of about 73.8%. The Earth-based control seeds recorded a rate of about 70.3%. The difference was therefore limited.

Students found that the seeds that had spent years in orbit could still germinate after returning to Earth. The experiment also found no harmful mutations in the student observations reported by the program. Some space-exposed seeds were reported to sprout slightly faster than the control seeds. The result gave the project a clear finding. Long exposure to the space environment had not stopped the tomato seeds from growing.

Why the control seeds were important?

The Earth-based seeds were a key part of the experiment. Without a control group, researchers would have had less information about whether any changes were linked to the space environment. The control seeds were kept under Earth conditions for the same period.

Students could therefore place the two groups side by side and compare their germination. This made the project different from a demonstration. Students were collecting and comparing data from two groups.

The experiment also brought science into classrooms through direct observation. Students were not only reading about NASA. They were using seeds connected to a NASA mission and recording what happened after planting them.

What the tomato experiment meant for space agriculture?

The findings added to knowledge about how seeds respond to long periods of exposure to space conditions. Seeds are important to future space missions because crews may need to grow food away from Earth. Long missions to the Moon or Mars would require methods for producing food over extended periods.

The tomato seed project showed that seeds could remain viable after prolonged exposure in orbit. It did not by itself prove that complete farming systems could operate on Mars or another planet. However, it provided information that could support later research into growing plants during space missions. The experiment also gave NASA information about seed viability after exposure to radiation and other space conditions.

The project also became a STEM education program

The tomato seeds were not only used for biological research. They became part of a large education effort. Millions of students were able to participate in an experiment linked to a NASA mission. They planted seeds, observed germination, recorded results and compared their findings. The project connected biology with aerospace science. It also gave teachers a way to use a space mission as a classroom activity.

NASA's seed experiments with Park Seed later continued. A 1997 program called MARS, or Mission to America's Remarkable Students, compared seeds kept in different environments. Another NASA and Park Seed effort in 2006 involved Cinnamon Basil seeds exposed aboard the International Space Station. The later projects extended the idea of using seeds to study exposure to space while involving students in the process.

What the NASA tomato seed experiment showed?

The 1984 tomato seed mission began as a one-year space exposure experiment. The Challenger disaster changed the schedule and left the LDEF in orbit for nearly six years. When the satellite returned in 1990, the seeds were still capable of germination.

The classroom program then gave students a chance to compare the space seeds with Earth-stored control seeds. The reported germination figures were 73.8% for the space-exposed seeds and 70.3% for the controls. The project therefore produced two outcomes. It generated information about seed survival after long space exposure and involved millions of students in hands-on science.

The story of the seeds also shows how a delayed space mission became an education experiment. What began with a planned one-year stay in orbit became a nearly six-year journey before the seeds reached classrooms.