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GRAIL takes off to the Moon
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A Delta II 7920H-10 Rocket lifted off from Space Launch Complex 17 (Pad 17B) at Cape Canaveral Air Force Station, Florida today at 9:08:52am EDT carrying NASA’s GRAIL (Gravity and Interior Laboratory) Mission that will map the Moon’s Gravity from crust to core. The mission was delayed on Thursday due to Upper Level Winds and teams also had to stand down on Friday when additional time was needed to fully understand a minor off-nominal situation that occurred after Thursday’s scrub.
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Launch Preparations began yesterday, just after 8pm EDT when engineers and technicians started preparations to roll the Mobile Service Structure to its Launch Position at a safe distance to the Launch Pad. Those preparations included retractions of access platforms and Launch Vehicle Closeouts. The 12-story tall tower began its short trip just after midnight and reached its launch position 30 minutes later. MST securing and final closeouts were performed. The area was cleared of all personnel and roadblocks were put in place in anticipation of liftoff. Prior to Countdown Initiation, the Vehicle was powered up and normal telementry was received confirming that everything was in good shape to start the countdown. After clock initialization, a planned 60-minute Hold at T-150 Minutes began. Polls were taken to ensure all station were ready for Terminal Countdown before starting it at 5:29:45am EDT. At L-2:40 Hours, RP-1 Fuel Loading commenced. It took 19 minutes and 5 seconds to fill the first stage tanks with 9,989 gallons of refined Kerosene. Another set of Polls followed before a GO for Liquid Oxygen Loading was given. LOX Load started at 6:46am EDT and was completed 25 Minutes later. 211,000 pounds of Propellants were on board the first stage after the tanking process. The tank was pressurized as part of test procedures before taking the LOX Level down to 95% again. Many tests of equipment followed, including communication link checks and range safety checkouts. At L-56 Minutes, Engine Slew Tests were conducted and returned nominal results. No systems problems occurred in today’s countdown. At T-15 Minutes, the clock stopped for a planned 20-minute hold. The hold was quiet as there was no need to take care of any technical items. Going down to T-4 Minutes, it became clear that Upper Winds were violating Weather Criteria. The Delta II Heavy needs lower wind profiles than other launch vehicles so that Upper Level Wind Violations are fairly common for the vehicle. The team elected to extend the hold and wait for the second opportunity of the day at 9:08am EDT. For that launch window, additional weather concerns were initially raised as thick clouds and anvil clouds were approaching from the west.
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 Photo: NASA Kennedy |
Weather Reconnaissance Aircraft reported that the clouds were still at an acceptable distance and transparent from a visual examination. Transparent clouds are less of a threat to Weather Criteria. Weather Balloon Data was used to assess the High Altitude Wind Situation and at 8:50am EDT, GREEN Conditions were observed that were 16% under the crucial wind speed limit. A new set of launch polls was performed and all stations reported “Go for Launch”. Six-and-a-half minutes prior to launch, both GRAIL Spacecraft transitioned to internal power which is a big milestone in the countdown. Two minutes later, the GRAIL Orbiters were in their launch configuration awaiting their ride to a parking orbit and eventually to the Moon. The countdown resumed at T-4 minutes and final vehicle reconfigurations on the Delta II were made including transfer to internal power, hydraulics reconfig and pressurizing the Oxygen and RP-1 Tanks. At T-2 minutes, the vehicle’s ordnances were armed and a final check was performed. During the final minute of the countdown, Range reported their GO and the Launch Enbable Switch was put in the proceed position. A GREEN BOARD was determined at T-13 seconds indictating that all systems were in proper configurations for blast off.
 Photo: NASA Kennedy |
Liftoff occurred on time at 9:08:52.775am EDT and the Delta II Rocket blasted off with 1.3 Million Pounds of thrust. During the first minute of flight, Mach 1 was achieved and the vehicle encountered Maximum Dynamic pressure. At T+74 seconds, the Ground-Lit Solid Rocket Boosters (6 GEM-46 SRBs) burned out. Those were jettisoned in packs of three at 80 and 81 seconds into the flight. The three remaining SRBs ignited and provided an additional boost up to a point 2 minutes and 33 seconds into powered flight when burnout occurred. First stage powered ascent continued. Main Engine Cutoff came at T+4:23 and stage separation followed 8 seconds later. Initial telementry indicates that the first stage with its RS-27A Engine performed flawlessly. The second stage ignited for the first time shortly after 1/2 Separation. Shortly after ignition on Stage 2, Payload Fairing separation was successfully completed jettisoning the two clampshell enclosures that protected the spacecraft at the Launch Pad and during powered ascent to maintain thermal limits. SECO-1 – the first shutdown of the AJ-10-118K engine – occurred right on time at 7:10 into the mission. GRAIL was delivered to space and coasted for 58 minutes in a Low Earth Parking Orbit under 100 nautical miles. During the coast, the so called Barbecue Roll Mode was initiated so that thermal requirements for the second stage and the spacecraft could be met. During the coast phase, no off nominal telementry was observed and vehicle performance was as expected. The second burn of the second stage began 65 minutes after liftoff and put the spacecraft at the correct speed for their tans-lunar cruise.
After 4 minutes and 32 seconds, the second stage shut down after a flawless burn. A re-orientation maneuver was initiated that put the stack into the proper position for GRAIL-A separation. Breakwires were cut and the first of the twins was on its own at T+1:19:52. Another orientation maneuver put the complex into the proper attitude to send GRAIL-B out to the Moon with successful separation at T+1:28:07. |
Photo: Thom Baur, United Launch Alliance
Launch Video
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A big round of applause sounded inside the Mission Operations Center as the team celebrated a successful Delta II Mission. NASA Administrator Charlie Bolden was also there to follow the launch and mission. He congratulated the team and recognized key launch personnel. GRAIL-A has now begun a 2,577,662-mile journey to the Moon. At 10:46am EDT, good solar array deployment was confirmed through a solid communication link. Its mirror twin, GRAIL-B, will take a longer route of 2,646,745 miles. Good solar arrays and solid communications were reported on GRAIL-B at 10:51am EDT. That means that intial vehicle statuses are positive. More thorough Spacecraft Status Polls and health checks will be performed over the course of the next 23 hours before GRAIL transitions mission phases for the first time. Both spacecraft will arrive at the Moon 25 hours apart from each other on December 31 and January 1, 2012. The GRAIL mission has a designed life of ~270 days. Visit the GRAIL Mission Info Page to view the most detailed Mission Timeline for GRAIL available on the Internet.
For Space Launch Complex 17, an era ends today. This was the final planned mission to lift off from the complex that has been around since the 1950s. United Launch Alliance indicted that the Complex will undergo demolition next year.
