In 1999, NASA sent 4 ladybugs aboard Columbia for 5 days to chase aphids; the aphids lost their ability to escape by falling, and the ladybugs still caught and ate them

In July 1999, space shuttle Columbia carried an unusual crew member into orbit as part of a student science project: four ladybugs. They flew in the STS-93 mission, which is described by NASA as a “planned five-day mission” commanded by Eileen Collins, the first female commander of the Space Shuttle. The University of Colorado Boulder’s press release regarding this mission stated that the experiment asked one simple question: if gravity disappeared, could ladybugs still eat aphids, their favorite food?

Why aphids need gravity to escape

On Earth, ladybugs climb plant stems in search of prey. Aphids feel the threat and drop straight down, with gravity helping them to pull away from the leaf and escape the bugs. Dropping is their main strategy to avoid the predators and it works because gravity gives them a quick, sure exit.

What happens when there is no "down"? The question came from a high school in Santiago, Chile, called Javiera High School for girls. The students pitched the idea to NASA's new Space Technology and Research for Students program, or STARS. Louis Stodieck, associate director of CU-Boulder's BioServe Space Technologies center, was named principal investigator on the program, according to a university release. The plan was to send ladybugs and aphids into orbit and film their behavior without gravity to guide them.

Four ladybugs, one microgravity habitat

The ladybugs made the trip in a small incubator, containing habitats for plants and insects, known as the Commercial Generic Bioprocessing Apparatus, or CGBA. This incubator hosted the “Ladybugs in Space” project on STS-93, as well as a small habitat for butterflies, which is confirmed in a technical paper titled ‘Science Research and Education Modules for the CGBA Spaceflight Incubator,’ written by BioServe engineers, including Stodieck, and published through SAE International. Cameras recorded the insects every day, allowing students to track their progress online. Meanwhile, classes in Colorado, Michigan, Texas, Florida, Ohio and Chile conducted similar experiments so students could compare microgravity with normal gravity.

Columbia launched from Kennedy Space Center on July 23, 1999. The official NASA website mission page shows that the mission duration was about five days and the payload of the space shuttle included the Chandra X-ray Observatory, while the ladybug experiment was among several other experiments.

What happened when there was no gravity

In orbit, the aphids had lost their one sure defense. Without gravity, falling off a leaf doesn't help an aphid escape; it simply drifts nearby instead of being carried away. Insects generally keep gripping surfaces with their legs even in microgravity, which is likely how the ladybugs kept moving and hunting; the aphids, though, no longer had gravity to turn a fall into an actual escape. The ladybugs were still able to find and eat the aphids, according to contemporary education-team accounts. This detail is repeated consistently in the mission's contemporary education materials, but it is from classroom-outreach reporting, not from a peer-reviewed results paper, because this was a K-12 science project, not a formal research study. NASA's own review of the flight, published to mark 25 years since the launch, says that STS-93 was a "successful five-day mission." It also had the crew working through several secondary middeck experiments alongside the main telescope deployment, of which the ladybug study was one.

A larger lesson on life without gravity

Though the ladybug experiment might seem like just another little classroom project, it was addressing a genuine scientific issue. If people ever grow food or manage pests on long space missions, or one day on other planets, scientists need to understand how basic animal behaviors change without gravity. It matters to anyone trying to keep a garden alive far from Earth: a predator that never ceases to hunt, and prey that loses its main defense.

More than two decades later, similar insect experiments still travel to the International Space Station, often run by students who were not even born when Columbia carried its four ladybugs into orbit. The bugs were small and the mission brief. But the question their work helped answer, how life adapts when gravity disappears, is part of how NASA and its research partners are thinking about growing food beyond Earth.