Jessica Ulrika Meir (IPA: /mɪər/; meer;[2] born (1977-07-01)July 1, 1977) is an American NASA astronaut, marine biologist, and physiologist.

She was previously an assistant professor of anesthesia at Harvard Medical School, Massachusetts General Hospital, Boston, following postdoctoral research in comparative physiology at the University of British Columbia.

She attributes her abiding dream of personally participating in space exploration to the love of nature she learned from her mother, and from her father's predilection for wandering and adventure.

[21] Meir earned a Ph.D. in marine biology in 2009 from the Scripps Institution of Oceanography for research on the diving physiology of emperor penguins and northern elephant seals.

[23] Meir did post-doctoral research at the University of British Columbia, raising bar-headed geese so their tolerance of high altitude and low oxygen levels during flight over the Himalayas could be studied in a controlled environment.

[6][23] For the 2012 academic year she continued her research as an assistant professor of anesthesia at the Harvard Medical School/Massachusetts General Hospital and then took a leave of absence to enter the astronaut corps.

Meir and her crewmates spent five days saturation diving from the Aquarius habitat as a space analogue for working and training under extreme environmental conditions.

The mission was delayed due to Hurricane Isadore, forcing National Undersea Research Center managers to shorten it to an underwater duration of five days.

Then, three days into their underwater mission, the crew members were told that Tropical Storm Lili was headed in their direction and to prepare for an early departure from Aquarius.

[7][28] At the time of NEEMO 4, Meir was leaning toward pursuing a PhD in a field related to evolutionary biology and/or life in extreme environments (astrobiology).

She was also fascinated by marine biology (which suited the NEEMO mission well), and hoped to coordinate a specific topic of study to combine these main interests.

[30] In 2016, she participated[31][32] in the ESA CAVES[8] mission[33][34] of the European Space Agency alongside Ricky Arnold, Sergei Korsakov, Aki Hoshide, Ye Guangfu and Pedro Duque.

[36] In April 2019 NASA announced that Meir had been assigned to the crew of International Space Station Expedition 61/62 as flight engineer, scheduled to launch aboard Soyuz MS-15 alongside Roscosmos cosmonaut Oleg Skripochka and MBRSC astronaut Hazza Al Mansouri, who would fly a short duration mission and land with the crew of Soyuz MS-12 eight days after launch.

[40][41] On October 18, 2019, Meir performed her first spacewalk alongside her colleague Christina Koch, replacing a faulty Battery Charging Discharging Unit.

[46] On February 6, 2020, Koch, alongside Soyuz MS-13 crew members Aleksandr Skvortsov and Luca Parmitano, returned to Earth, following which Meir, Skripochka and Andrew Morgan transferred over to Expedition 62.

[53][54][55] Astronauts are allowed to bring a number of personal items to the International Space Station, and two among Meir's choices were an Israeli flag and a pair of novelty socks with Stars of David and menorahs.