When Nigerian researcher Temidayo Oniosun chose a melon seed called the egusi to send up on a space mission, it wasn't just about science - it was about symbolism.

The egusi, a staple in many West African kitchens, became the unlikely ambassador of the continent's heritage aboard the International Space Station with their launch from NASA's Kennedy Space Center in Florida earlier this month.

"Everybody in Nigeria eats egusi, and even other people in some West African countries and Africans in the diaspora, so this (mission) is something they could identify with," said Oniosun. "Egusi is the seed that tells our story."

The egusi, a primary source of protein, were among a cohort of heritage seeds from Costa Rica, Guatemala, Armenia and Pakistan packed into specialised test tubes on the Crew-11 space capsule launched on August 1.

The Nigerian melon seeds, which were sourced from local markets in Oyo State in southwestern Nigeria, spent seven days in orbit aboard the ISS before returning to Earth with the crew from the previous space capsule on August 9.     

"It was amazing because the launch the previous day had been cancelled due to the weather. So there was a lot at stake during the launch. But the moment the rocket actually lifted off, that felt surreal," Oniosun said.

Nigeria's space agency NASRDA sent egusi and five other crop seeds up on the NASA mission for State-funded agricultural research purposes. Oniosun's egusi were added as a cultural initiative by Space in Africa, a market intelligence company he founded focusing on the African space and satellite industry.

The seeds that were in orbit are now being distributed to researchers to study the effect of their outer space sojourn on their nutritional properties.

University of Florida scientist Wagner Vendrame, one of the researchers, said the seeds would be propagated in vitro and studied for genetic changes triggered by microgravity characteristic of outer space.

"By looking at the changes in the plants and the seeds themselves, we can tell - are those plants still the same? Would they still provide the same level of nutrition to astronauts?"

Oniosun said his goal is for crops native to Africa to be part of future food systems on the moon and Mars if space habitation expands over the coming decades.