SpaceX: 10,
9,
8…
NASA Launch Commentator Josh Finch: Seven,
six,
five,
four,
three,
two,
one,
zero.
And liftoff of the Falcon 9 rocket and a Dragon
spacecraft packed with science and supplies
for the International Space Station, humanity’s
home in low-Earth orbit.
The Falcon 9 has cleared the tower.
SpaceX ascent commentary is performed by several
people.
Propulsion engineer calls out propulsion events.
Avionics engineer calls out avionics health
and Dragon separation.
The range coordinator calls Air Force satellite
control network acquisition and loss of signal.
And the ground station specialist calls out
the SpaceX antenna acquisition and loss of
signal.
We are 40 seconds into the flight of the Falcon
9.
One minute, five seconds after liftoff, Falcon
9 will reach transonic speed.
The vehicle will pass through an area of maximum
aerodynamic pressure called max Q.
At one minute, 18 seconds after liftoff, this
is the point where mechanical stress on the
rocket reaches its peak because of the rocket’s
velocity and resistance created by Earth’s
atmosphere.
And the vehicle is supersonic.
Ascent commentator: Vehicle is experiencing
maximum dynamic pressure.
Finch: And confirmation of max Q.
One minute, 30 seconds into flight.
And the second-stage engine chill has begun.
Around two minutes, 35 seconds into flight,
the nine Merlin engines will sequentially
shut down.
You’ll hear the term, “MECO,” which
means main engine cutoff.
