Fruit flies, Dr. Ocorr said, are “actually much closer in some respects to humans than the mouse or rat models are.”
The fruit flies, as well as 40 mice for another experiment, are waiting to travel on a SpaceX mission that was called off Thursday with less than a half-hour left in the countdown because of a nearby lightning strike. The rocket is to lift a Dragon capsule with nearly 6,000 pounds of supplies, equipment and experiments including the fruit flies and mice.
The next opportunity is Saturday at 5:07 p.m. If the rocket gets off the ground then — forecasters expect more unsettled weather — it would arrive at the space station on Monday, when the space station crew will grab the Dragon capsule and attach it to a docking port. After about a month attached to the space station, the Dragon will undock and return to Earth with a splashdown in the Pacific.
The fruit fly eggs are to hatch in orbit, while the adults will lay more eggs. The flies will return to Earth in the Dragon. Dr. Ocorr and her colleagues will then study the flies for abnormalities in the skeletal and heart muscles and the shape of the hearts.
The researchers have sent flies to the space station before, in January 2015. “We did see cardiac dysfunction,” Dr. Ocorr said. There were changes in the expression of genes associated with the cardiovascular system.
The mice will help address another aspect of astronaut health: bone strength.
Without gravity pulling down, the bones of astronauts turn fragile — losing 1 to 2 percent of bone mass each month — although NASA has found that exercise can slow down that loss.
The researchers want to test on the mice a drug that stimulates bone growth.
For long space missions, like a trip to Mars, “we can’t have our astronauts breaking a hip or something,” said Dr. Chia Soo, a medical researcher at the University of California, Los Angeles, who is the principal investigator on the experiment,…