Robyn Gatens, left, deputy director, ISS Division and system capability leader for Environmental Control and Life Support Systems (ECLSS) at NASA Headquarters in Washington, tours laboratories in the Space Station Processing Facility at the agency's Kennedy Space Center in Florida, on June 13, 2018. To her right is Molly Anderson, deputy ECLSS capability lead at Johnson Space Center in Houston. They are viewing plant growth chambers and seeing firsthand some of the capabilities in the center's Exploration Research and Technology Programs.

Robyn Gatens, left, deputy director, ISS Division and system capability leader for Environmental Control and Life Support Systems (ECLSS) at NASA Headquarters in Washington, tours laboratories in the Space Station Processing Facility at the agency's Kennedy Space Center in Florida, on June 13, 2018. Standing behind her is Ralph Fritsche, long-duration food production project manager at Kennedy. Gatens is viewing plant growth chambers and seeing firsthand some of the capabilities in the center's Exploration Research and Technology Programs.

Inside a laboratory in the Neil Armstrong Operations and Checkout Building at NASA's Kennedy Space Center in Florida, Dr. Luke Roberson, right, principal investigator for research and development in Swamp Works, explains the algae bio reactor to Robyn Gatens, center, deputy director, ISS Division and system capability leader for Environmental Control and Life Support Systems (ECLSS) at NASA Headquarters in Washington, on June 13, 2018. At far left is Molly Anderson, deputy ECLSS capability lead at Johnson Space Center in Houston. They are seeing firsthand some of the capabilities in the center's Exploration Research and Technology Programs.

KENNEDY SPACE CENTER, FLA. — At NASA Kennedy Space Center, a new environmental control and life support system is offloaded from a truck. The life support system is part of the payload on the second return-to-flight test mission, STS-121, aboard space shuttle Discovery to the International Space Station. The system will add to the station’s oxygen-making capabilities and could provide enough oxygen for up to six people. Managed by Marshall Space Flight Center in Huntsville, the system was built by Hamilton Sundstrand Corp. in Connecticut. Discovery will carry more than two tons of equipment and supplies to the station. This second return-to-flight test mission is to carry on analysis of safety improvements that debuted on the first return-to-flight mission, STS-114, and build upon those tests. The launch is targeted for a date no earlier than May. Photo credit: NASA/Jack Pfaller

KENNEDY SPACE CENTER, FLA. — At NASA Kennedy Space Center, a new environmental control and life support system is moved into the Space Station Processing Facility. The life support system is part of the payload on the second return-to-flight test mission, STS-121, aboard space shuttle Discovery to the International Space Station. The system will add to the station’s oxygen-making capabilities and could provide enough oxygen for up to six people. Managed by Marshall Space Flight Center in Huntsville, the system was built by Hamilton Sundstrand Corp. in Connecticut. Discovery will carry more than two tons of equipment and supplies to the station. This second return-to-flight test mission is to carry on analysis of safety improvements that debuted on the first return-to-flight mission, STS-114, and build upon those tests. The launch is targeted for a date no earlier than May. Photo credit: NASA/Jack Pfaller

KENNEDY SPACE CENTER, FLA. — A truck arrives at NASA Kennedy Space Center carrying a new environmental control and life support system. The life support system is part of the payload on the second return-to-flight test mission, STS-121, aboard space shuttle Discovery to the International Space Station. The system will add to the station’s oxygen-making capabilities and could provide enough oxygen for up to six people. Managed by Marshall Space Flight Center in Huntsville, the system was built by Hamilton Sundstrand Corp. in Connecticut. Discovery will carry more than two tons of equipment and supplies to the station. This second return-to-flight test mission is to carry on analysis of safety improvements that debuted on the first return-to-flight mission, STS-114, and build upon those tests. The launch is targeted for a date no earlier than May. Photo credit: NASA/Jack Pfaller

KENNEDY SPACE CENTER, FLA. — At NASA Kennedy Space Center, a new environmental control and life support system is moved into the Space Station Processing Facility after being removed from its shipping container. The life support system is part of the payload on the second return-to-flight test mission, STS-121, aboard space shuttle Discovery to the International Space Station. The system will add to the station’s oxygen-making capabilities and could provide enough oxygen for up to six people. Managed by Marshall Space Flight Center in Huntsville, the system was built by Hamilton Sundstrand Corp. in Connecticut. Discovery will carry more than two tons of equipment and supplies to the station. This second return-to-flight test mission is to carry on analysis of safety improvements that debuted on the first return-to-flight mission, STS-114, and build upon those tests. The launch is targeted for a date no earlier than May. Photo credit: NASA/Jack Pfaller