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Good morning, world! Today is a momentous occasion for the Virgin Orbit team: operations for the first orbital launch demonstration of our LauncherOne rocket are well underway. 
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After a promising pre-flight briefing this morning, weather remains favorable for our target launch window today. As a reminder, we will not be livestreaming this flight — but stick around and refresh this feed for updates as the action happens.pic.twitter.com/pKzlStVnNi
Between the COVID-19 crisis and Memorial Day, it’s a bit of an odd time to be launching a rocket — but we’re thrilled to be approaching our first official launch window after years of working methodically through the LauncherOne program. We’re feeling more ready than ever.
Since opening the doors to our Long Beach facility in 2015, a tremendous amount of work has gone into designing, manufacturing and testing LauncherOne, an air-launched vehicle built specifically to serve small satellite customers around the world.pic.twitter.com/jND6CfCmDh
Today, our main focus is collecting as much data as possible and learning more than we ever have before about our launch system.
The test payload onboard LauncherOne today has allowed us to test our full end-to-end system — from analyzing a payload to integrating it into the rocket and ultimately, if the space gods are with us, to deploying it in space.
LOX (liquid oxygen) loading is progressing smoothly, an operation which began a little after 8 AM this morning. We successfully completed fuel loading operations for RP-1 (Rocket Propellant-1) yesterday evening.pic.twitter.com/GbgrVL7bJo
We want to be able to fly often, on short notice, and affordably from various launch sites — so using ubiquitous liquid propellants like LOX/RP-1 just makes sense!
The way that we support and launch our rocket is quite different from vertically launched platforms, so here's a handy guide to the various trailers that make up our mobile ground support equipment.pic.twitter.com/SvZJLfAvRG
LOX loading will take a little while longer, so it's a good time to quickly recap the milestones we've crossed to get to this orbital flight test.
At only 5 years old, we're pretty young for a rocket company. But as we matured, we've pursued three difficult tasks in parallel: establishing a high-rate production capability, commissioning our flying launch pad, and proving out our launch system.
We've made great progress building out our factory, adding invaluable tools to accelerate our production cycle, like a hybrid additive-subtractive manufacturing machine. If you were to walk around the factory today, you'd see a half-dozen rockets in various stages of production.pic.twitter.com/OeCFjICnaS
Meanwhile, other teams worked on modifying Cosmic Girl for flight, stripping out all extraneous weight and strengthening the left wing where the rocket hangs. And let’s not forget that we also fully designed, manufactured and tested the launch pylon in-house.pic.twitter.com/tnf2uPrK14
Last summer, we completed a beautiful drop test over @EdwardsAFB, which allowed us to collect really valuable aerodynamics data but also verified the release mechanism of our pylon.pic.twitter.com/JsxrurQuUo
Then, around the end of April this year, we wrapped up our development program with a final cryogenic captive carry flight. That flight represented the most true-to-form rehearsal of our entire launch system to date, and we couldn't have been more pleased with the results.pic.twitter.com/OLQn4HVeXb
It's been a long journey thus far, but really this is just the beginning of Virgin Orbit's story. Upon successful ignition of the NewtonThree main stage engine today, we would be the first team to air-launch a liquid-fueled orbital class rocket.
UPDATE: LOX loading is now complete. We're proceeding smoothly through our countdown and are currently on track for our target takeoff time of approximately 11:40 AM Pacific.
Our flight crew is preparing to board the aircraft. Cosmic Girl is piloted today by our Chief Test Pilot Kelly Latimer, who has been the wind beneath our wings throughout our entire flight test program.pic.twitter.com/uNwejXxWJx
We also have a rotating pair of launch engineers onboard Cosmic Girl. Today's dynamic duo is Bryce Schaefer and Jason Panzarino (who coincidentally were born on the exact same day in 1990 but are otherwise unrelated).pic.twitter.com/4AE9vllsSq
After taking off from Mojave, Cosmic Girl will fly due southwest to our drop point just south of the Channel Islands. Once we reach the drop point, we'll enter into a loop that we call the "racetrack" as we wait for final go/no-gos.pic.twitter.com/mg3Bdc1Hek
As we fly laps around the racetrack, the team will be checking conditions for release — making sure that the wind levels aren't too high and that we have a strong telemetry connection so we can receive data after the drop.
Confirming a smooth takeoff! Cosmic Girl is officially airborne for our first attempt at an orbital launch demo.
The ground stations we've enlisted to track Cosmic Girl and LauncherOne for this flight are spread across the globe: Mexico, Antarctica, and Mojave. We also have a telemetry dish on the roof of our Long Beach HQ.
We've just completed our first cold pass through the racetrack. The rocket has autonomously detected it's in the launch zone. Currently all systems are go for flight.
Commencing final checks for the Terminal Count Autosequence. Once triggered, LauncherOne's computers will take full control of the system in the minutes leading up to final countdown and release.
Confirming both vehicles are healthy at this time.
We've officially initiated the Terminal Count Autosequence, which means we're approximately less than 15 minutes away from releasing LauncherOne.
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