It might have remained one of the greatest mysteries of the universe, destined never to be solved until a freak recent discovery by the crew of the International Space Station (ISS).
The subject? A tomato grown from seed in microgravity by US astronaut Francisco “Frank” Rubio as part of an agricultural experiment.
Rubio was accused of having eaten the fruit when it inexplicably disappeared more than eight months ago. However, the tiny specimen, or at least its remnants, have now been found, according to members of the seven-strong crew during a live stream this week to celebrate the orbiting outpost’s 25th anniversary.
“Our good friend Frank Rubio has been blamed for quite a while for eating the tomato. But we can exonerate him. We found the tomato,” Nasa astronaut Jasmin Moghbeli said, reported by space.com.
She did not specify where on the 356ft space station the 1in-wide red dwarf tomato was located, or in what condition.
But the news of its existence will have come as a relief for Rubio, a lieutenant colonel in the US army who returned to Earth on 27 September after spending a record 371 days in space, the most for any US astronaut in history.
At his post-landing briefing he lamented the loss of the tomato, which was cultivated as part of a in-space salad-growing experiment designed to advance knowledge of how to sustain astronauts during lengthy missions, and feared he would be for ever branded a tomato thief.
“Hopefully somebody will find it someday, a little shriveled thing,” he told reporters, having claimed he spent up to 20 hours searching for it after it disappeared during a harvesting operation.
“I was pretty confident that I Velcroed it where I was supposed to Velcro it. And then I came back, and it was gone.”
The specific project of which the tomato was part is known officially as Veg-05, a Nasa tag to avoid the mouthful of its official name, the “pick-and-eat salad-crop productivity, nutritional value, and acceptability to supplement the ISS food system” investigation.
As well as evaluating the viability and effects of spaceflight on fruit crop growth under different light conditions, the experiment also offers astronauts taste tests and a survey to determine if interacting with plants in the spaceflight environment offered any psychological lift or otherwise affected their mood.
The ISS has its own vegetable production system, known as Veggie, and the opportunity to work on it is, to many astronauts, one of the perks of space travel. Rubio spoke fondly of his time growing and harvesting, despite the tomato mishap, and Nasa officials say the work provides priceless knowledge that will benefit future generations of astronauts.
“We’ve learned a lot more about this crop and we’ll continue to learn so much. We’ll get as much science out of this as possible,” Dr Gioia Massa, life sciences project scientist at Florida’s Kennedy space center, said in a Nasa article published online.
The infamous Rubio tomato turned out to be one of only 12 red dwarves successfully germinated and grown to ripeness in space during the Veg-05 project, compared with more than 100 in a parallel experiment conducted on Earth, according to Nasa.