A United Launch Alliance Atlas V rocket launches on the Department of Defense’s Space Test Program 3 (STP-3) mission from Space Launch Complex 41 at Cape Canaveral Space Force Station, Tuesday, Dec. 7, 2021. The mission’s Space Test Program Satellite-6 (STPSat-6) spacecraft hosts NASA’s Laser Communications Relay Demonstration (LCRD) and the NASA-U.S. Naval Research Laboratory Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder. Credit: NASA/Joel Kowsky

LCRD Is On Its Way!

The Laser Communications Relay Demonstration (LCRD) mission has successfully launched, completed two Centaur engine burns, and is on its way! The Department of Defense’s (DOD) Space Test Program 3 (STP-3) mission sent two satellites including the Space Test Program Satellite-6 (STPSat-6) spacecraft, which hosted two

A United Launch Alliance Atlas V rocket carrying the Department of Defense’s Space Test Program 3 (STP-3) mission is seen illuminated by spotlights at Space Launch Complex 41 at Cape Canaveral Space Force Station, Tuesday, Dec. 7, 2021, from NASA’s Kennedy Space Center in Florida. The mission’s Space Test Program Satellite-6 (STPSat-6) spacecraft hosts NASA’s Laser Communications Relay Demonstration (LCRD) and the NASA-U.S. Naval Research Laboratory Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder. Credit: NASA/Joel Kowsky

Launch preparations are underway, but because of high velocity upper level winds the new launch time is 5:19 a.m. EST for the Department of Defense’s (DOD) Space Test Program 3 (STP-3) mission, managed by the U.S. Space Force (USSF) Space Systems Command (SSC), from Launch Complex 41 on Cape Canaveral Space Force Station in Florida.

The United Launch Alliance (ULA) Atlas V 551 rocket will carry satellites and technology experiments, including NASA payload Laser Communications Relay Demonstration (LCRD) and the NASA-U.S. Naval Research Laboratory Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder, to space.

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A Look at What’s on Board

The United Launch Alliance (ULA) Atlas V rocket and the United States Space Force’s STP-3 mission on launch day. The mission hosts NASA’s Laser Communications Relay Demonstration (LCRD) and the NASA-U.S. Naval Research Laboratory Ultraviolet Spectro-Coronagraph (UVSC). Credit: NASA

Today’s Space Test Program 3 (STP-3) mission contains technology experiments from government, military, and research institutions including two NASA payloads that will help advance the future of space exploration. NASA’s primary payload, hosted on the U.S. Department of Defense’s Space Test Program Satellite-6 (STPSat-6) spacecraft, is the Laser Communications Relay Demonstration (LCRD).

Like technology demonstrations that have come before it, LCRD is a giant step toward making operational laser, or optical, communications a reality. About the size of a king-size mattress, LCRD will send and receive data over infrared lasers at 1.2 gigabits per second from geosynchronous orbit to Earth.

Just how much data can we transmit at once with laser communications? Sending a high-resolution map of

The United Launch Alliance (ULA) Atlas V rocket and the United States Space Force’s STP-3 mission sit on Space Launch Complex 41 (SLC-41) at Cape Canaveral at sunset. Credit: United Launch Alliance

U.S. Space Force’s Space Systems Command STP-3 Mission

A United Launch Alliance (ULA) Atlas V 551 rocket stands ready for liftoff at Launch Complex 41 on Cape Canaveral Space Force Station (CCSFS) for the U.S. Space Force’s (USSF) Space Systems Command (SSC) Space Test Program 3 (STP-3) mission, which hosts NASA’s Laser Communications Relay Demonstration (LCRD) and the NASA-U.S. Naval Research Laboratory Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder.

Launch is scheduled for 4:04 a.m. EST this morning, with a two-hour launch window. Follow along on NASA Television for the live broadcast.

Meteorologists with the U.S. Space Force 45th Weather Squadron predict a more than 90% chance of favorable weather for liftoff.

Here’s a look at some of today’s countdown and ascent milestones. All times are approximate:

COUNTDOWN
Hr/Min/Sec    Event
– 00:55:00      Start flight control final preparations to raise hydraulic pressures
– 00:45:00      Pressurize Main Engine Pneumatic System to flight pressure
– 00:16:00      Initiate fuel fill sequence
– 00:10:00      Weather briefing with Atlas Launch Weather Officer
– 00:05:00      Fuel fill sequence is complete; water deluge system actuation pressure adjustment is performed; Atlas L02 at flight level; Centaur L02 at Flight level; Centaur LH2 at flight level
– 00:04:00      Hazardous gas monitoring is complete; automatic computer sequencer takes control for all critical events through liftoff; Atlas first stage LO2 replenishment is secured, allowing the tank to be pressurized for flight
– 00:03:00      Atlas tanks reach flight pressure
– 00:02:00      Atlas first stage and Centaur upper stage switch to internal power; L02 and LH2 topping for Centaur will stop in 10 seconds
– 00:01:30      Launch control system is enabled

LAUNCH AND SPACECRAFT DEPLOYMENT
All Times Approximate
Hr/Min/Sec    Event
00:00:00.1     RD-180 Engine Ignition
00:00:01.1     Liftoff of the Atlas V
00:00:03.9     Begin Pitch/Yaw Maneuver
00:00:34.7     Mach 1
00:00:48.7     Max Q (moment of peak mechanical stress on the rocket)
00:01:46.7     Solid rocket booster jettison
00:03:30.2     Payload fairing jettison
00:04:27.4     Atlas booster engine cutoff (BECO)
00:04:33.4     Atlas Centaur separation
00:04:43.3     Centaur first main engine start (MES-1) 
00:10:38.4     Centaur first main engine cutoff (MECO-1)
01:07:22.1     Centaur second main engine start (MES-2)
01:12:25.6     Centaur second main engine cutoff (MECO-2)
06:24:48.2     Centaur third main engine start (MES-3)
06:27:26.3     Centaur third main engine cutoff (MECO-3)
06:30:15.4     STPSat-6 Separation
07:10:02.4     LDPE-1 Separation
08:08:02.3     End of mission