Northrop Grumman’s Pegasus XL rocket will take about 11 minutes to place NASA’s Ionospheric Connection Explorer, or ICON, satellite into a roughly 357-mile-high (575-kilometer) orbit after an airborne launch off Florida’s east coast.
The nearly 53,000-pound (24-metric ton) rocket will drop from the belly of a modified L-1011 carrier plane, named Stargazer, flying on an easterly path over the Atlantic Ocean at an altitude of 39,000 feet (11,900 meters).
The Pegasus rocket, launching on its 44th orbital mission, will fire three solid-fueled stages in succession, then release NASA’s ICON satellite into orbit to begin a mission studying how weather in Earth’s atmosphere influences plasma conditions at the edge of space in the ionosphere, a boundary that can interfere with radio communications and satellite navigation.
The images below were recorded from a previous flight.
Data source: NASA/Northrop Grumman
T-00:00: Pegasus Drop
The 57-foot-long Pegasus XL rocket is released from the Orbital Carrier Aircraft off the east coast of Florida at an altitude of 39,000 feet above the Atlantic Ocean and a speed of Mach 0.82.
T+00:05: First Stage Ignition
After falling for five seconds to a distance of about 300 feet below the L-1011, the first stage Orion 50S XL solid-fueled motor of Pegasus is ignited to begin the powered journey to orbit with ICON. Between drop and ignition, the Pegasus XL’s destruct system is armed.
T+00:36: Max-Q
The Pegasus XL flies through the phase of maximum aerodynamic pressure, and the Orion 50S XL continues firing, reaching a peak power level of about 163,000 pounds of thrust.
T+01:17: First Stage Burnout
The Orion 50S XL first stage motor consumes all of its solid-fuel propellant and burns out at an altitude of more than 177,000 feet, or 53.9 kilometers.
T+01:33: First Stage Separation/Second Stage Ignition
The spent first stage motor is jettisoned at T+plus 1 minute, 33 seconds, to prepare for the second stage of flight. The first stage casing falls into the Atlantic Ocean. One second later, Orion 50 XL motor ignites at an altitude of 237,000 feet (72.1 kilometers) to continue the flight into orbit.
T+02:10: Fairing Jettison
The 50-inch-diamter (1.3-meter) payload fairing that protected the ICON during atmospheric ascent is separated once heating levels drop to predetermined limits at an altitude of around 381,000 feet (116 kilometers). The second stage motor continues its burn with 44,000 pounds of thrust.
T+02:48: Second Stage Burnout
The Orion 50 XL second stage motor consumes all its solid fuel, then begins a four-minute coast phase for the rocket to climb to the targeted altitude for the ICON mission. During this time, the rocket’s on-board computer calculates when it needs to ignite the third stage based on the performance of the booster to this point.
T+07:00: Second Stage Separation
The Pegasus XL’s second stage separates from the third stage.
T+07:11: Third Stage Ignition
The Pegasus XL’s third stage Orion 38 motor fires for a planned 69-second burn to accelerate the ICON satellite to orbital velocity.
T+08:20: Third Stage Burnout
The third stage Orion 38 solid-fueled motor burns out. The mission is targeting a circular orbit 357 miles (575 kilometers) above Earth at an inclination of 27 degrees.
T+11:20: ICON Separation
The attitude control thrusters on the Pegasus XL’s third stage will re-orient the vehicle for the deployment of the ICON satellite. The spacecraft is programmed to begin extending its solar panel within about 100 seconds of separation from the Pegasus third stage.
This video captures the final portion of the launch countdown and follows the Atlas 5 rocket’s flight through arrival in the preliminary orbit carrying the Curiosity rover headed for Mars. (Membership Required)
SpaceX aborted an attempted flight Monday of the company’s Starhopper test rocket, a prototype for the company’s next-generation Starship vehicle. The hop test was to fly to a height of around 500 feet (150 meters) over SpaceX’s launch site at Boca Chica, Texas.
A SpaceX Falcon 9 rocket lifted off from Vandenberg Space Force Base in California at 11:02 p.m. PDT Tuesday (2:02 a.m. EDT; 0602 UTC Wednesday) with another batch of 52 Starlink internet satellites.
