Throwback Thursday

On Feb. 23, the four MMS observatories — seen here stacked one atop the other — were encapsulated within the two-piece payload fairing at the Astrotech payload processing facility in Titusville, Florida.


The fairing, with MMS sealed inside, approaches the Vertical Integration Facility on Space Launch Complex 41 on Cape Canaveral Air Force Station in Florida on Feb. 27.
Payload fairing containing MMS arrives at Space Launch Complex 41

T-2 Hours and Counting

The countdown has resumed and tanking operations are about to begin. This process takes roughly two hours and starts with chilldown of the ground equipment and transfer lines, allowing the hardware to acclimate to the cold temperatures of the propellants.

The Centaur’s engine runs on 4,150 gallons of liquid oxygen and 12,680 gallons of liquid hydrogen, and the Atlas booster stage uses 48,860 gallons of liquid oxygen in combination with a refined kerosene fuel called RP-1. RP-1 is not a cryogenic propellant like the others and was loaded yesterday.