A SpaceX Dragon supply craft has undocked from the International Space Station (ISS) to bring tons of research materials back to Earth, the US space agency NASA said on Monday.

The spacecraft spent about a month attached to the orbiting space outpost before undocking at 5:05 PM on Monday. The capsule was due to splashdown on Wednesday off the coast of Florida.

NASA said that the capsule was "bringing tons of
@ISS_Research, including a space radiation vest and orbiting plant experiments, back to Earth."

Among the items making their journey back to Earth are a special vest designed to protect astronauts from high doses of radiation and a study on the effect of exposure to the space environment on extra virgin olive oil.

The supply mission, which set off from Earth in late November, was the 26th conducted by SpaceX in cooperation with NASA. Among the supplies delivered were solar panels, a special variety of tomato to improve the diet available to the crew on long missions, and so-called Moon Microscopes.

The latter is "a kit for in-flight medical diagnosis that includes a portable hand-held microscope and a small self-contained blood sample staining device," NASA said.

Ice cream was included in the cargo as a surprise. The first SpaceX supply mission to the ISS took place in 2012.