Microbes from Sue, the Tyrannosaurus Rex at Chicago's Field Museum, are headed to space, albeit a few days later than originally planned.
A launch of the SpaceX Falcon 9 rocket from the Kennedy Space Center, planned for Monday afternoon, was scrubbed because of a helium leak on the rocket. If the problem can be fixed, the rocket will lift off on Friday afternoon.
Project Merccuri, as it's been dubbed, hopes to teach researchers how 48 microbes from different places on Earth compare to each other and to those already found on the International Space Station.
Officials said understanding how microbes behave in microgravity is important for planning long-term manned space flight.
The microbe collected from Sue -- the Paenibacillus mucilaginosus -- is widely used in "microbial fertilizer" for agriculture, according to the University of California Davis.
Microbes collected that weren't selected to travel to space will be studied by scientists at UC Davis and at the Argonne National Laboratory in Lemont, Ill.
Live video of Monday's launch will be carried on NASA.gov.