NASA MESSENGER Spacecraft Arrives in Florida to Begin FInal Preparations for May Launch

NASA’s MESSENGER spacecraft, the first Mercury orbiter, has arrived in
Florida after being shipped from NASA’s Goddard Space Flight Center in
Greenbelt, Md. MESSENGER – short for MErcury Surface, Space
ENvironment, GEochemistry, and Ranging – will be launched on a six-year
mission aboard a Boeing Delta II rocket on May 11.

Secured in an air-conditioned transportation van, MESSENGER arrived at
the Astrotech Space Operations processing facilities near Kennedy Space
Center, where it was offloaded and taken into a high bay clean room.

After the spacecraft is removed from its shipping container by employees
of the Johns Hopkins University Applied Physics Laboratory, builders of
the spacecraft, their first activity will be to perform an initial
state-of-health check. Then processing for launch can begin including
checkout of the power systems, communications systems and control
systems. The thermal blankets will also be attached for flight.

A major milestone will occur in mid-April with the installation of the
two solar arrays, which will then undergo a deployment test. MESSENGER
would then be ready for loading of the on-board hydrazine fuel and
nitrogen tetroxide oxidizer used for propulsion and spacecraft control.
The fully assembled and fueled spacecraft will undergo spin balance
testing in preparation for a stable cruise toward Mercury.

Finally, MESSENGER will be hoisted atop the Delta upper stage, the solid
propellant Star 48 third stage booster made by Alliant which will propel
the spacecraft from earth orbit on its interplanetary trajectory. After
a final integrated functional test, MESSENGER will be ready to be
installed into its transportation canister for the 15-mile trip to the
launch pad at Cape Canaveral Air Force Station.

Meanwhile, at Space Launch Complex 17, the build-up and checkout of the
Boeing Delta II Heavy expendable launch vehicle will be underway. The
activity on Pad 17-B is currently scheduled to begin on March 31 with
the erection of the first stage. The nine extra-large, strap-on solid
boosters will follow, erected in sets of three during the week of April
1-7. Next, the second stage will be hoisted atop the first stage on
April 13.

After the Delta II is fully erected on the pad, vehicle electrical
checks will begin.

A countdown test with the first stage loaded with liquid oxygen will
occur on April 21. A Simulated Flight Test, a plus count, will occur
the following day. This activates the electrical and mechanical flight
systems on the vehicle as they will occur from liftoff through
spacecraft separation.

Finally, on April 27, the compact 1.2-ton MESSENGER spacecraft will
arrive at the pad and be lifted atop the Delta II. After a critical
integrated test, the Flight Program Verification on April 30, the
fairing will be placed around the spacecraft on May 4. =20

The final pre-launch preparations and countdown activities begin three
days before launch. Liftoff is targeted for the opening of a 12-second
launch window at 2:26 a.m. EDT on Tuesday, May 11. =20

MESSENGER will fly past Venus three times and Mercury twice before
starting its year-long orbital study of Mercury in July 2009. The Venus
flybys, in November 2004, August 2005 and October 2006, will use the
planet’s gravity to guide MESSENGER toward Mercury’s orbit. Mercury
flybys in October 2007 and July 2008 will fine-tune the MESSENGER path
and allow the spacecraft to gather data critical to planning the mission
once it is in orbit.

MESSENGER is the next launch in NASA’s Discovery Program of lower cost,
highly focused missions for NASA’s Office of Space Science. Government
oversight of launch preparations and the countdown management of launch
day is the responsibility of NASA’s John F. Kennedy Space Center. The
launch service is provided to NASA by Boeing Launch Services.