New York (CNN Business) People near the Mojave Desert may have caught a strange sight Wednesday morning: A 70-foot rocket plummeting from the sky.

a "drop test," was the final step toward reaching that goal. It's was part of a pre-planned test carried out by Virgin Orbit , the space startup backed by British entrepreneur Richard Branson . The company wants to fire satellites into orbit using rockets that launch mid-air from under the wing of a plane. Wednesday's spectacle, during which a Virgin Orbit LauncherOne rocket was intentionally left to freefall back to the ground fora "drop test," was the final step toward reaching that goal.

LauncherOne took off from a Mojave runway nestled beneath the wing of a modified Boeing 747 airplane, nicknamed Cosmic Girl. Once the plane reached about 35,000 feet, the typical cruising altitude for commercial aircraft, the rocket was released. It then slammed to the ground at a test range at Edward's Air Force Base.

During operational missions, the LauncherOne rocket would fire up its engine shortly after detaching from Cosmic Girl's wing and continue flying into orbit in order to drop off satellites for Virgin Orbit's customers. But for the drop test, a dummy rocket was used to simulate the entire commercial flight experience — just without the part where the rocket zooms off into orbit.

Virgin Orbit said in a blog post that it would be "monitoring and rehearsing a million things" during the drop test — but it was primarily intended to "ensure the rocket and aircraft separate cleanly" and allow engineers to "observe how the rocket behaves" during freefall. It was the last planned test flight before Virgin Galactic will attempt an orbital mission.

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