Note: The timeline is based on a June 25 liftoff.

T-00:00	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+01:16.4	Ground SRM Burnout
The six ground-start Alliant TechSystems-built solid rocket motors consume all their propellant and burn out.
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.
T+01:20.5	Jettison Ground SRMs
The six spent ground-started solid rocket boosters are jettisoned in sets of three at T+80.5 and 81.5 seconds to fall into the Atlantic Ocean.
T+02:39.5	Jettison Air-Lit SRMs
Having burned out four seconds, the three spent air-started solid rocket boosters are jettisoned toward the Atlantic Ocean.
T+04:23.4	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+04:31.5	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+04:37.0	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 Mars Exploration Rover into the proper orbit during the launch sequence.
T+04:42.0	Jettison Payload Fairing
The 9.5-foot diameter payload fairing that protected the Mars Exploration Rover atop the Delta 2 during the atmospheric ascent is jettisoned is two halves.
T+08:48.4	Second Stage Cutoff 1
The second stage engine shuts down to complete its first firing of the launch. The rocket and attached Mars Exploration Rover are now in a coast period before the second stage reignites.
T+67:56.8	Second Stage Restart
Delta's second stage engine reignites for a firing that will raise the orbit further.
T+70:08.8	Second Stage Cutoff 2
The second stage shuts down. 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.
T+71:01.3	Stage Separation
The liquid-fueled second stage is jettisoned from the rest of the Delta 2 rocket.
T+71:38.3	Third Stage Ignition
The Thiokol Star 48B solid-fueled third stage is then ignited to propel the Mars Exploration Rover out of Earth orbit.
T+73:05.4	Third Stage Burnout
Having used up all its solid-propellant, the third stage burns out to completed the powered phase of the launch sequence for Mars Exploration Rover-B.
T+77:48.3	Yo-Yo Despin
Two small yo-yo-like structures are released from the third stage to reduce the spinning motion the Delta rocket and Mars rover are experiencing in preparation for satellite separation.
T+77:53.3	Spacecraft Separation
NASA's Mars Exploration Rover-B is released from the launch vehicle for the seven month, 305 million mile cruise to the Red Planet.

Data source: Boeing.