T-00:00 |
Liftoff |
The ULA Delta 2 rocket's main engine and twin vernier steering thrusters are started moments before launch. The six ground-start strap-on solid rocket motors are ignited at T-0 to begin the mission. |
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T+01:17.1 |
Ground SRM Burnout |
The six ground-start Alliant TechSystems-built solid rocket motors consume all their propellant and burn out. |
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T+01:19.0 |
Air-Lit SRM Ignition |
The three remaining solid rocket motors strapped to the Delta 2 rocket's first stage are ignited. |
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T+01:20.5 |
Jettison Ground SRMs |
The six spent ground-started solid rocket boosters are jettisoned in sets of three to fall into the Atlantic Ocean. |
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T+02:39.5 |
Jettison Air-Lit SRMs |
Having burned out, the three spent air-started solid rocket boosters are jettisoned toward the Atlantic Ocean. |
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T+04:23.2 |
Main Engine Cutoff |
After consuming its RP-1 fuel and liquid oxygen, the Rocketdyne RS-27A first stage main engine is shut down. The vernier engines cut off moments later. |
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T+04:31.2 |
Stage Separation |
The Delta rocket's first stage is separated now, having completed its job. The spent stage will fall into the Atlantic Ocean. |
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T+04:36.7 |
Second Stage Ignition |
With the stage jettisoned, the rocket's second stage takes over. The Aerojet AJ10-118K liquid-fueled engine ignites for the first of its two firings to boost the GRAIL satellites out of Earth orbit. |
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T+04:41.0 |
Jettison Payload Fairing |
The 10-foot diameter payload fairing that protected the GRAIL spacecraft atop the Delta 2 during the atmospheric ascent is jettisoned is two halves. |
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T+07:09.7 |
Second Stage Cutoff 1 |
The second stage engine shuts down to complete its first firing of the launch after reaching a 90-nautical-mile circular orbit. The rocket and attached GRAIL spacecraft are now in a coast period before the second stage reignites. |
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T+67:56.7 |
Second Stage Restart |
Delta's second stage engine reignites for the firing that accelerates the payload out of Earth orbit on the circuitous route to the Moon. |
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T+72:28.8 |
Second Stage Cutoff 2 |
The stage shuts down to complete its second burn after propelling GRAIL on the departure trajectory from Earth. |
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T+81:58.8 |
GRAIL-A Deploy |
The first of the twin GRAIL spacecraft is released from the launch dispenser system atop the rocket's second stage. |
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T+90:13.8 |
GRAIL-B Deploy |
NASA's second GRAIL spacecraft is released from the Delta 2-Heavy rocket to begin the journey from the Earth to the Moon to map the lunar gravity field. |