What if you planned a scientific experiment and something went wrong with the equipment or the circumstances of the experiment? You’d be smart to design backup experiments.
TWO SPIDERNAUTS – Backup experiments
When Bioserve, the Colorado company in charge of live animal experiments on the International Space Station, decided to send a jumping spider into space, they had backups in place. The lead spider was supposed to be Cleopatra, a zebra jumping spider (Salticus scenicus).

But the experiment had strict parameters. They would video the spiders for an hour a day for several days. The video feeds to Earth were expensive and no more time could be allowed for recording how the spiders operated in the microgravity of space.
Most spiders spin webs to catch prey. Jumping spiders, however, actively hunt their food. They jump to catch a fly. But when a spider jumps in microgravity…it just floats away. Would the spiders be able to adapt and hunt?
Cleopatra, the lead spider, was camera shy. She may have done amazing jumps in space, but seldom did she appear on film.
Instead, Nefertiti, the backup spider (Phiddipus johnsonii), took the limelight. She was photographed jumping to catch fruit flies in her habitat. In fact, she leapt as no other jumping spider has ever jumped. She laid down an anchor thread, just as she might on Earth. Then, she leapt for the spider. The resolution on the video is too low for slow-motion that would allow scientists to measure the angle of her jump. But watching you can see that it’s a flat jump with little arc. After she catches the fruit fly, Nefertiti allowed the anchor thread to pull her back to the wall of the habitat, like a bungee cord.
The video of Nefertiti jumping answered the scientific questions. Yes, jumping spiders can adapt to microgravity. Even more exciting was the video of Nefertiti’s first hunt back on Earth. She leapt toward the fruit fly—but her aim was off. She fell flat. It took three tries for Nefertiti to catch—and finally eat—her meal.
Without the backup spider—Nefertiti—the experiment would’ve failed. Cleopatra didn’t cooperate, but Nefertiti did.
THREE TELESCOPES – Backups for backups
Another example of a backup experiment occurred in 1919 when astronomers wanted to photograph the solar eclipse in May that year.
Einstein had recently put forth his theory of general relativity. It talked about the effect of gravity and acceleration on light. Light, the theory said, could bend or curve if pulled by a strong enough gravity.
OK. Now, HOW do you design an experiment to prove/disprove THAT theory?
Fortunately, astronomer Arthur Eddington thought he knew. During an eclipse, he suggested, they could measure the position of distant stars. As the light passed by our sun SOL, Einstein’s theory said the light would bend slightly. If the stars’ positions appeared to move, the light had bent.
The 1919 solar eclipse was the perfect time to measure the position of stars behind the sun. They sent a team to Principe Island (the Chocolate Islands, so named because of Cacao Plantations), just off the coast of Africa.

A BACKUP team went to Brazil. They expected that the images from Principe Island would be the best images to measure the phenomenon. But on Principe just at the time of the eclipse, a storm struck. It cleared enough for some photos to be made. The book, ECLIPSE: How the 1919 Solar Eclipse Proved Einstein’s Theory of General Relativity is for elementary readers and will release on October 8, 2019.
The Brazil team had problems of their own. The heat warped the telescope enough to blur the images. However, they also had a second—BACKUP—telescope. It only had 4” lenses instead of the larger ones they hoped to use. But it was better than nothing, they reasoned.
Indeed, the 4” telescope in Brazil–the backup experiment–produced the best images of the eclipse and helped prove Einstein’s theory of general relativity. The BACKUP team with the BACKUP telescope!
