Lockheed Martin technicians prepare for the application of new foam over the manhole cover on the lower end of external tank No. 119.

Lockheed Martin technicians in the Vehicle Assembly Building at NASA's Kennedy Space Center prepare for the application of new foam over the manhole cover on the lower end of external tank No. 119. The manhole was removed to access the area where the tank's four liquid hydrogen engine cutoff sensors were replaced. Once reinstalled, the manhole required new foam to be applied. The tank is being prepared to launch Space Shuttle Discovery on mission STS-121 in July. Photo credit: NASA/Jim Grossmann