Mission Control Center
STS-62 Status Report #15
Friday, March 11, 1994, 8 a.m. CST

The STS-62 mission passed the halfway point this morning as crew members 
kept busy with middeck and orbiter activities. 

Marking the mid-point of the mission, Commander John Casper switched 
several of the environmental control systems to their backups for on-
orbit check out.  The procedures require crew members to switch to the 
alternate humidity separator, cabin pressure and temperature control 
systems, orbiter heaters, and carbon dioxide removal system. 

Columbia also changed attitudes for the first time since launch day.  
Columbia is now orbiting with its tail pointing toward the Earth and the 
payload bay pointing in the direction of travel or the "ram" position.  
With the maneuver, Casper closed and opened sample trays for the Long 
Duration Space Environment Candidate Material Exposure (LDCE) experiment.  
The LDCE consists of three identical sample plates with 264 samples of 
various materials used in space vehicles.  One of the sample plates will 
be exposed to the space environment for most of the mission. One will be 
exposed only when the  payload bay is pointing in the ram position - or 
pointing into the direction of travel - and a third is exposed only when 
the orbiter is not in the ram position. 

Mission Specialist Marsha Ivins was interviewed by students at the Bronx 
High School of Science.  The students asked a variety of questions about 
the microgravity experiments being conducted during the mission on living 
and working in space. 

Also today, Mission Specialist Sam Gemar and Pilot Andy Allen each 
completed 45-minute ramp tests in the lower body negative pressure unit, 
and performed more tests with the Middeck 0-Gravity Dynamics Experiment.  
Astronauts also performed the standard checks of the protein crystal 
growth and rodent experiments housed in Columbia's middeck.