NASA designed Cell Science-04 to study gene expression and survival in tardigrades across generations aboard the International Space Station (ISS), with potential relevance to astronaut health during long missions.
NASA had cited an earlier benchmark in 2007, when tardigrades survived and generally reproduced during an 11-day low Earth orbit flight aboard the Foton-M3 capsule. Cell Science-04 centered on the species Hypsibius exemplaris and was designed to examine the animals’ responses while they lived and reproduced in station hardware.
SpaceX’s CRS-22 cargo mission carried the experiment to orbit after launching from Kennedy Space Center at 1:29 p.m. EDT (17:29 UTC) on June 3, 2021. NASA later reported that station Commander Akihiko Hoshide placed the tardigrades in the Bioculture System on July 13.
NASA’s preflight plan set two preservation points: one cohort after seven days of on-orbit culture and another after 61 days. Thomas Boothby, the experiment’s principal investigator, said the longer interval was expected to encompass about four generations. The plan covered both short-term and multigenerational survival.
Researchers intended to compare the orbital animals with a ground group kept on a closely aligned schedule, as well as separate groups exposed to drying or freezing stress. NASA’s investigation description said the analysis would examine gene expression and seek genes involved in the tardigrades’ responses to demanding space conditions. RNA interference was included as a method for testing the roles of selected genes.
NASA identified research into astronaut stress responses and possible countermeasures for long missions as potential applications. The health connection was presented as a research aim, not an established outcome.
