The 2,478 Baby Jellyfish NASA Sent to Space — and the Ones That Came Home Dizzy

What happened?

The jellyfish belonged to Dorothy B. Spangenberg, a research professor at Eastern Virginia Medical School in Norfolk, Virginia. By the 1990s she had spent decades raising moon jellies (Aurelia aurita) by the thousands in her lab, and local reporters called her “the jellyfish lady.” She liked them because they transform quickly: a moon jelly starts life as a polyp, a tiny stalk stuck to a surface. Given the right chemical signal, the polyp splits into a stack of discs, and each disc swims off as an ephyra, a baby jellyfish shaped like a little eight-armed star.

NASA had a practical reason to care. Its press kit for the mission noted that more than half of astronauts got space sickness in their first few days in orbit: nausea, vomiting, and dizziness, with some symptoms lasting for days after landing. The culprit seemed to be the inner ear, which senses “down” using tiny crystals called otoliths. In orbit, those crystals stop sending reliable signals.

Jellyfish have a surprisingly similar system. Around the rim of an ephyra sit sense organs called rhopalia, and inside them are clusters of crystals called statoliths. When the jellyfish tilts, the crystals shift and press on sensory hairs, which tells the animal which way is up. If you wanted to know how a gravity sensor builds itself without gravity, a jellyfish gave you hundreds of them at once in a small container.

So Spangenberg’s experiment flew on STS-40, also called Spacelab Life Sciences-1. It was the first shuttle mission dedicated entirely to life sciences. Columbia launched from Kennedy Space Center on June 5, 1991, and landed at Edwards Air Force Base in California on June 14. Of the mission’s 18 investigations, ten studied the human crew, seven studied rodents, and one studied jellyfish.

The polyps rode in flasks of artificial seawater. Some had been chemically nudged (with iodine or the hormone thyroxine) to start making ephyrae 48 or 24 hours before launch. Others got their nudge in orbit, about eight hours after liftoff. That meant some babies began developing on Earth and finished in space, while others were formed entirely in weightlessness. Identical groups stayed on the ground as controls. Tamara Jernigan, one of the mission specialists, was later listed as a co-author on the published results.

The jellyfish multiplied. The figure usually cited is roughly 60,000 jellyfish by the end of the mission, though the published papers focus on the samples studied rather than a headcount.

Why was it strange?

At first glance the space jellyfish looked fine. Under the microscope their gravity sensors had formed with all the expected parts: crystal-filled sacs, light-sensing spots, and sensory hair cells. They grew the normal number of arms, too.

The problem showed up when they tried to swim. A healthy ephyra moves by pulsing, squeezing its bell in a smooth, rhythmic beat. According to the team’s 1994 reports in Advances in Space Research, pulsing abnormalities turned up in roughly 18 percent of the space-developed ephyrae, compared with about 3 percent of the ground controls. The researchers described incomplete pulses, spasms, arms beating out of sync, twitches after a pulse, and odd “wave” motions. Ephyrae kept in space also lost more of their statoliths than their earthbound siblings did.

The strange part is the mismatch. The gravity sensors looked normal and still didn’t seem to work normally. Growing up without gravity had changed something that a microscope couldn’t easily see.

The same thread — Microgravity — continues in The Teenager Who Sent Two Spiders to Spin Webs in Space.

What did scientists learn?

The team’s careful conclusion was that some space-formed ephyrae “may have developed abnormal rhopalia,” because normal pulsing depends on gravity sensors that develop and work properly. That’s a “may.” The experiment showed a correlation, not a full explanation, and jellyfish are not small humans.

Still, the comparison matters. Gravity-sensing organs, from jellyfish rhopalia to human inner ears, appear to need gravity while they develop, not just while they’re used. In a 1997 newspaper interview, Spangenberg said a follow-up shuttle flight in 1994 carried 126 more jellies to probe how much gravity they needed. By her account, they behaved normally at about one-third of Earth’s gravity. Below that, they tended to swim in circles, and “often they would stop pulsing.”

Another animal the lab could not ignore: Laika: The Moscow Stray Who Orbited Earth, and the Truth Hidden for 45 Years.

How does it affect us today?

The jellyfish experiment belongs to a long line of research into how bodies adapt to spaceflight, a field that matters more as missions get longer. Space motion sickness is still common among astronauts, and readapting to Earth’s gravity after landing is still a real challenge.

The jellyfish also raise a question that sounds like science fiction but is now asked seriously: what happens to an animal, or eventually a person, that develops in low gravity? If gravity sensors need gravity to form properly, then reproduction and childhood on the Moon or Mars, or in a space station, would involve more than adults learning to cope. Spangenberg’s dizzy ephyrae are one early, small data point in that conversation, and her one-third-gravity estimate makes some people curious about Mars, whose gravity is about 38 percent of Earth’s.

Elsewhere in the space stories: The Corned Beef Sandwich That Got NASA Hauled Before Congress.

Fun fact

Spangenberg’s car had a license plate that read “JFNSPC,” short for “jellyfish in space.”

Sources

• Spangenberg DB, Jernigan T, Philput C, Lowe B. “Graviceptor development in jellyfish ephyrae in space and on Earth” — Advances in Space Research 14, no. 8 (1994): 317–25 (primary source)
• Spangenberg DB, Jernigan T, McCombs R, et al. “Development studies of Aurelia (jellyfish) ephyrae which developed during the SLS-1 mission” — Advances in Space Research 14, no. 8 (1994): 239–47 (primary source)
• “STS-40” — NASA mission page
• “STS-40 Press Kit: Spacelab Life Sciences-1” — NASA (1991)
• Larry Maddry, “For 30 Years, EVMS Researcher Has Had a Soft Spot for Jellyfish” — The Virginian-Pilot, September 20, 1997 (via Virginia Tech Digital Library)