John "JC" Carver, a payload integration engineer with NASA Kennedy Space Center's Test and Operations Support Contract, uses a FluorPen to measure the chlorophyll fluorescence of Arabidopsis thaliana plants inside the growth chamber of the Advanced Plant Habitat (APH) Flight Unit No. 1. Half the plants were then harvested.The harvest is part of an ongoing verification test of the APH unit, which is located inside the International Space Station Environmental Simulator in Kennedy's Space Station Processing Facility. The APH undergoing testing at Kennedy is identical to one on the station and uses red, green and broad-spectrum white LED lights to grow plants in an environmentally controlled chamber. The seeds grown during the verification test will be grown on the station to help scientists understand how these plants adapt to spaceflight.