In 1973, NASA sent about two spiders into space to test web-building without gravity; within days, they adapted and spun complete webs in orbit

Imagine being placed in an environment where there is no clear up or down and then being expected to build a structure normally shaped with gravity's help. In 1973, NASA effectively presented that challenge to two unlikely space travellers: spiders named Arabella and Anita. The pair flew aboard Skylab 3, the second crewed mission to America's first space station. Their task was unusual but scientifically intriguing: researchers wanted to discover whether spiders could construct their familiar webs in weightlessness. What happened over the following weeks showed that the creatures could do something remarkable: adapt. The experiment began with a teenager's question

The idea did not originate with a veteran NASA scientist. It came from Judith "Judy" Miles, a 17-year-old student from Lexington, Massachusetts, who responded to a NASA initiative inviting students to suggest experiments. Miles wanted to know how spiders would spin their webs without Earth's gravity. Her proposal ultimately became a real Skylab experiment. On July 28, 1973, astronauts Alan Bean, Jack Lousma and Owen Garriott launched for Skylab. Joining them were several much smaller passengers, including minnows, fish eggs, pocket mice, fruit-fly pupae and Arabella and Anita. The mission would last 59 days.

Arabella struggled at first

Life without gravity did not come naturally to the spiders. NASA's experiment records describe Arabella initially moving with an erratic "swimming" motion after being released into her enclosure. A day later, however, she had produced a rudimentary web around the corners of the cage. By the following day, a complete web had appeared. It was an important observation. The spider had never experienced anything resembling the conditions aboard Skylab, yet it had managed to perform one of its most recognisable behaviours. NASA's historical records say the spiders' earliest webs lacked the normal circular pattern. As the mission continued, however, their web-building improved, with more radial threads appearing as they adjusted to weightlessness.

Astronauts gave the experiment an unexpected twist

The experiment did not go entirely according to the original plan. After seeing Arabella's progress, the astronauts extended the protocol by providing additional water and even pieces of rare filet mignon. On August 13, Garriott removed half of Arabella's existing web to see what she would do. Arabella consumed what remained but initially refused to construct another. After receiving water, she started again and NASA records say the replacement web was better than the previous one, suggesting she was adapting to microgravity. Anita was later placed in the experimental cage and showed a similarly confused response at first.

Their webs were different from those on Earth

The experiment demonstrated that gravity affected web construction, but its absence did not prevent spiders from building. The Smithsonian notes that the spiders eventually spun webs in space using finer thread in response to the weightless environment. Neither Arabella nor Anita survived the nearly two-month mission, but both were returned to Earth with the astronauts. NASA subsequently transferred the spiders and experimental equipment to the Smithsonian. Anita is preserved in a vial and is part of the National Air and Space Museum collection.

A student's idea became part of space history

The Skylab spider experiment might sound whimsical more than five decades later, but behind it was a serious question about how living organisms respond when one of Earth's most constant forces disappears. Arabella and Anita provided an unexpectedly simple answer: at first, their behaviour and webs changed dramatically. Given time, however, they adjusted. Perhaps the most remarkable part of the story is where the experiment began. One teenager wondered what a spider would do in space. NASA gave her question a chance and two tiny astronauts supplied the answer.