Mars Exploration Rovers Launch Status Report 14 May 2003

MISSION: Mars Exploration Rover (MER-2)

• LAUNCH VEHICLES: Delta II/Delta II Heavy
• LAUNCH PADS: 17-A
• LAUNCH DATES: June 5
• LAUNCH TIMES: 2:16 p.m. / 2:55:29 p.m. EDT

Mating of the MER-2 entry vehicle to the cruise stage was
completed on May 7. The spacecraft has completed its weight and center of
gravity determination and underwent its initial spin balance testing. On
May 11 the spacecraft was fueled. Tomorrow night, May 15, will be second
spin test now that the spacecraft is fueled.

During routine testing of the cruise stage and the MER-2 rover
over the weekend, an unexpected measurement in the rover’s power system was
observed. Troubleshooting is under way but it is not expected to delay the
schedule of planned pre-launch spacecraft preparations at this time.

The mission will have two launch opportunities each day during the
launch period, which is scheduled to close on June 19. Arrival at Mars is
set for Jan 4, 2003, regardless of the launch date within that period.

On Cape Canaveral Air Force Station, the solid rocket booster
erection begins today with the first three set of motors being attached to
the first stage, the second set of three will be erected on Thursday, May
15, and the final set will be hoisted into position on Friday, May 16. The
first stage was erected on Pad 17-A on Wednesday, April 23. The second
stage erection was completed on Monday, April 28 and the fairing was hoisted
into the white room on April 30. The Simulated Flight test of the first
stage was successfully completed May 9. The spacecraft is scheduled to be
mated to the third stage in the Payload Hazardous Servicing Facility (PHSF)
on May 23. MER-2 will be transported to the launch pad on May 27.

MISSION: Mars Exploration Rover (MER-1)

• LAUNCH VEHICLE: Delta II Heavy
• LAUNCH PAD: 17-B
• LAUNCH DATE: June 25, 2003
• LAUNCH TIME: 12:38:16 a.m. / 1:19:19 a.m. EDT

On MER-1, rover installation onto the base petal and lander air
bag installation were completed on May 9. The operation to install the
backshell over the lander begins tonight and is scheduled to be complete on
Friday. Full integration of the MER-1 entry vehicle (back shell, heat
shield, lander and rover) is to be completed by May 21 and followed by
mating the entry vehicle to the cruise stage.

The MER-B vehicle’s first stage is on Pad 17-B and the solid
rocket boosters will be erected May 19-24; the second stage will be hoisted
atop the first stage on May 28.