Nation IN BRIEF : FLORIDA : Astronauts Monitor Heart Performance

Columbia’s astronauts, apparently satisfied with NASA’s plan to forgo a spacewalk to make cargo bay repairs, conducted more medical tests in orbit and enjoyed taped messages from home on their fifth day in orbit. But flight officials at Florida’s Kennedy Space Center said it was generally business as usual for the astronauts, who monitored their heart and lung function and blood pressure, took more urine samples and measured their body mass. Preliminary results indicate the astronauts’ cardiac output, or the amount of blood returning to the heart, remains higher in space than on Earth for longer than expected. Tests conducted after the flight on 2,478 tiny jellyfish and 29 white rats aboard Columbia will add to scientists’ knowledge about the effects of weightlessness on living things.