SpaceX's Dragon cargo ship docks at the space station in time for astronaut's birthday

This long exposure photo shows the launch of a SpaceX Falcon 9 rocket on a resupply mission for NASA to the International Space Station from Pad 39A at Kennedy Space Center, seen from Merritt Island, Fla., Sunday, Aug. 29, 2021. The SpaceX shipment of ants, avocados and a human-sized robotic arm rocketed toward the International Space Station on Sunday. Credit: Malcolm Denemark/Florida Today via AP

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SpaceX's latest Dragon cargo ship arrived at the International Space Station (ISS) today (Aug. 30) to deliver an experimental robotic arm and a wealth of other research equipment and supplies just in time for one astronaut's birthday.

"Congratulations to NASA and SpaceX teams and many thanks. No one's ever sent me a spaceship for my birthday before," NASA astronaut Megan McArthur radioed Mission Control just after docking. It's her 50th birthday today.

"That's a most excellent birthday present," NASA's Mission Control in Houston replied.

The gumdrop-shaped Dragon docked with the station's Harmony module at 10:30 a.m. EDT (1430 GMT) today, ending a 32-hour-orbital chase. The station and Dragon were sailing 264 miles (425 kilometers) above western Australia at the time.

A SpaceX shipment of ants, avocados, and a human-sized robotic arm rocketed toward the International Space Station on Sunday. It is the company's 23rd for NASA in just under a decade.

A recycled Falcon rocket blasted into the predawn sky from NASA's Kennedy Space Center. After hoisting the Dragon capsule, the first-stage booster landed upright on SpaceX's newest ocean platform, named "A Shortfall of Gravitas." SpaceX founder Elon Musk continued his tradition of naming the booster-recovery vessels in tribute to the late science fiction writer Iain Banks and his Culture series.

The Dragon is carrying more than 4,800 pounds (2,170 kilograms) of supplies and experiments, and fresh food including avocados, lemons, and even ice cream for the space station's seven astronauts.

The Girl Scouts are sending up ants, brine shrimp, and plants as test subjects, while University of Wisconsin-Madison scientists are flying up seeds from mouse-ear cress, a small flowering weed used in genetic research. Samples of concrete, solar cells, and other materials also will be subjected to weightlessness.

A Japanese start-up company's experimental robotic arm, meanwhile, will attempt to screw items together in its orbital debut and perform other mundane chores normally done by astronauts. The first tests will be done inside the space station. Future models of Gitai Inc.'s robot will venture out into the vacuum of space to practice satellite and other repair jobs said chief technology officer Toyotaka Kozuki.

Another experiment will test how a tiny drug-delivering implant performs in microgravity, and yet another will gauge the responses of various materials to the space environment.

As early as 2025, a squad of these arms could help build lunar bases and mine the moon for precious resources, he added.

There are now two Dragons parked at the ISS: the newly arrived cargo capsule and a crewed variant, which brought NASA astronauts McArthur and Shane Kimbrough, Japanese space flyer Akihiko Hoshide, and the European Space Agency's Thomas Pesquet to the orbiting lab in April.

Those four astronauts are scheduled to return to Earth in November while their crewmates (NASA astronaut Mark Vande Hei and Russian cosmonauts Pyotr Dubrov and Oleg Novitskiy) remain aboard to continue their mission. The cargo Dragon will come down sooner; it's scheduled to spend about a month at the ISS, NASA officials have said.

Both versions of Dragon survive re-entry, making ocean splashdowns under parachutes. This capability separates the resupply Dragon from other currently operational cargo craft, which burn up in Earth's atmosphere when their missions are done.