transfer vehicles or atvs supplied the iss with food and equipment during the early 21st century the last atv georges lematre launched in july 2014 the uncrewed cargo ship like most others servicing the iss was designed for onetime use after delivering its cargo these capsules are filled with the stations garbage they burn up harmlessly in the earths atmosphere during reentry planting space lettuce in april 2014 a spacex flight delivered an unusual cargo red romaine lettuce seeds each nestled inside a special plant pillow full of fertilizer and a type of clay this was the first fresh food production system aboard the iss this first crop was returned to earth for analysis where laboratory tests showed the lettuce was safe to eat iss astronauts were able to enjoy the lettuce for themselves after their second crop was harvested in august 2015 the oneyear crew in march 2015 scott kelly and mikhail kornienko arrived at the iss on a special mission they were tasked with spending almost a full year aboard the ship to study how longduration space missions affect the human body scotts identical twin mark who remained on earth was also part of the experiment marks health could help estimate how scotts body might have changed if he had not been in space science aboard the iss the iss has hosted hundreds scientific experiments throughout the years by students as well as professional researchers the ship has plant habitats aquariums and several rodent facilities that research how longterm spaceflight affects living creatures one of the earliest iss outreach programs called earthkam allowed students to request photos of specific places on earth taken from a camera installed in the station emergency planning in addition to delivering new astronauts to the station soyuz spacecraft serve as an escape pod in the event of an emergency evacuation at least one soyuz is always docked to the station for this purpose 2018 was an eventful year for the soyuz in august a small leak was discovered and repaired on the soyuz ms9 which was docked to the iss and in october another soyuz had an emergency abort in flight first allwoman spacewalk in october 2019 nasa flight engineers christina koch and jessica meir concluded the first allwoman spacewalk both crew members are part of the 2013 astronaut class which was the first to have an equal number of men and women the spacewalk had originally been scheduled for earlier in march but was postponed because the station did not have two mediumsized spacesuits that could be used without extensive configuration the dragon arrives in may 2020 spacex made history by becoming the first commercial company to send astronauts to the iss spacecraft commander doug hurley and joint operations commander bob behnken both veteran nasa astronauts remained aboard the iss for two months conducting scientific experiments and spacewalks they guided the crew dragon capsule to a safe landing off the coast of florida in early august note for arrivals dates of installation