Anita and Arabella, two female cross spiders (Araneus diadematus) went into orbit in 1973 for the Skylab 3 space station. Like the STS-107 experiment, the Skylab experiment was a student project. Judy Miles, from Lexington, Massachusetts, wanted to know if spiders could spin webs in near-weightlessness.

The experiment was set up so that a spider, released by an astronaut (Owen Garriot) into a box similar to a window frame, would be able to build a web. A camera was positioned to take photos and videos of the webs and spider activities.

Three days before the launch, each spider was fed a house fly. They were provided with a water-soaked sponge in their storage vials. The launch took place on July 28, 1973. Both Arabella and Anita needed some time to adapt to near-weightlessness. Neither spider, kept in holding vials, voluntarily entered the experiment cage. Both Arabella and Anita made what has been described as 'erratic swimming motions' upon ejection into the experiment cage. After a day in the spider box, Arabella produced her first rudimentary web in a corner of the frame. The next day, she produced a complete web.

These results prompted the crewmembers to extend the initial protocol. They fed the spiders bits of rare filet mignon and provided additional water (note: A. diadematus can survive up to three weeks without food if an adequate water supply is available.) On August 13th, half of Arabella's web was removed, to prompt her to build another. Although she ingested the remainder of the web, she did not build a new one. The spider was provided with water and proceeded to build a new web. This second complete web was more symmetrical than the first full web.

Both spiders died during the mission. They both showed evidence of dehydration. When the returned web samples were examined, it was determined that the thread spun in flight was finer than that spun preflight. Although the web patterns made in orbit were not significantly different from those that were built on Earth (aside from a possible unusual distribution of radial angles), there were differences in the characteristics of the thread. In addition to being thinner overall, the silk spun in orbit exhibited variations in thickness, where it was thin in some places and thick in others (on Earth it has a uniform width). The 'start and stop' nature of the silk appeared to be an adaptation of the spider to control the elasticity of the silk and resulting web.

Spiders in Space Since Skylab

After the Skylab experiment, Space Technology and Research Students (STARS) conducted a study on spiders planned for STS-93 and STS-107. This was an Australian experiment designed and conducted by students from Glen Waverley Secondary College to test the reaction garden orb weaver spiders to near-weightlessness. Unfortunately, STS-107 was the ill-fated, catastrophic launch of the Space Shuttle Columbia. CSI-01 started on ISS Expedition 14 and was completed on ISS Expedition 15. CSI-02 was performed on ISS Expeditions 15 through 17.

The International Space Station (ISS) conducted two well-publicized experiments on spiders . The first investigation was Commercial Bioprocessing Apparatus Science Insert Number 3 or CSI-03. CSI-03 launched to the ISS on the Space Shuttle Endeavour on November 14, 2008. The habitat included two orb weaver spiders (Larinioides patagiatus or genus Metepeira), which students could view from Earth to compare the feeding and web-building of the spiders in space against those housed in classrooms. The orb weaver species were selected based on the symmetrical webs they weave on Earth. The spiders appeared to thrive in near-weightlessness.

The second experiment to house spiders on the ISS was CSI-05. The goal of the spider experiment was to examine the changes in web construction over time (45 days). Again, students had the opportunity to compare the activities of spiders in space with those in classrooms. CSI-05 used golden orb weaver spiders (Nephila claviceps), which produce golden yellow silk and different webs from the orb weavers on CSI-03. Again, the spiders constructed webs and also successfully caught fruit flies as prey.

Golden orb weaver spiders were selected for CSI-05. Joe Raedle / Getty Images

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