Spaceflight Now: Delta launch report

GPS 2R-7 launch timeline
Updated: January 26, 2001

T-00:00.0 Liftoff
The 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.
T+01:03.0 Ground SRM Burnout
The six ground-start Alliant TechSystems-built solid rocket motors consume all their propellant and burn out.
T+01:05 Air-Lit SRM Ignition
The three remaining Alliant TechSystems-built solid rocket motors strapped to the Delta 2 rocket's first stage are ignited.
T+01:06 Jettison Ground SRMs
The six spent ground-started solid rocket boosters are jettisoned in sets of three at T+66 and T+67 seconds to fall into the Atlantic Ocean.
T+02:12 Jettison Air-Lit SRMs
Having burned out, the three spent air-started solid rocket boosters are jettisoned toward the Atlantic Ocean.
T+04:23 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.
T+04:31 Stage Separation
The Delta rocket's first stage is separated now, having completed its job. The spent stage will fall into the Atlantic Ocean.
T+04:37 Second Stage Ignition
With the stage jettisoned, the rocket's second stage takes over. The Aerojet AJ118-K liquid-fueled engine ignites for the first of two firings needed to place the upper stage and GPS 2R-7 satellite into the proper orbit.
T+04:58 Jettison Payload Fairing
The 9.5-foot diameter composite payload fairing that protected the GPS 2R-7 satellite atop the Delta 2 during the atmospheric ascent is jettisoned is two halves.
T+10:54 Second Stage Cutoff 1
The second stage engine shuts down to complete its first firing of the launch. The rocket and attached GPS 2R-7 spacecraft are now in a 9-minute coast period before the second stage reignites. The orbit achieved should be 94 by 212 nautical miles, inclined 36.90 deg.
T+19:56 Second Stage Restart
Delta's second stage engine reignites for a short firing to continue the journey to space.
T+20:31 Second Stage Cutoff 2
The second stage shuts down after a 35-second burst. Over the next minute, tiny thrusters on the side of the rocket will be fired to spin up the vehicle in preparation for stage separation. The orbit achieved should be 103 by 686 nautical miles, inclined 37.21 deg.
T+21:24 Stage Separation
The liquid-fueled second stage is jettisoned from the rest of the Delta 2 rocket having completed its role in the launch.
T+22:01 Third Stage Ignition
The Thiokol Star 48B solid-fueled third stage is then ignited to complete GPS 2R-7's delivery into its intended orbit around Earth.
T+23:28 Third Stage Burnout
Having used up all its solid-propellant, the third stage burns out to completed the powered phase of the launch sequence. Over the next two minutes, two small yo-yo-like structures are released from the third stage to reduce the spinning motion the Delta rocket and GPS 2R-7 are experiencing in preparation for satellite separation.
T+25:21 GPS 2R-7 Separation
The U.S. Air Force's NAVSTAR Global Positioning System Block 2R-7 spacecraft is released into space. The Delta should have placed the satellite into a transfer orbit with a high point of 10,998 nautical miles and low point of 101 nautical miles inclined 39.00 deg. The satellite will circularize its orbit.

Data source: Boeing.

Flight Data File
Vehicle: Delta 2 (7925)
Payload: GPS 2R-7
Launch date: Jan. 30, 2001
Launch window: 0743-0811 GMT (2:43-3:11 a.m. EST)
Launch site: SLC-17A, Cape Canaveral, Fla.

Pre-launch briefing
Delta 2 rocket - Overview of the Delta 2 7925-model rocket used to launch GPS satellites.

Global Positioning System - Description of the U.S. Air Force's space-based navigation network.

GPS constellation - Chart shows the current status of the orbiting GPS satellite fleet.

Delta directory - See our coverage of preview Delta rocket flights.