To reach orbit, a rocket must fight the curve of spacetime

Space · Published 2 November 2026 Swipe more like this →

In short: Launching into space is more than just moving upward; it is a violent struggle against the very fabric of reality. To escape Earth, a spacecraft must overcome a gravitational funnel that bends the universe itself, requiring precise mastery of trajectory and raw physics.

Isaac Newton's third law of motion, which states that every action produces an equal and opposite reaction, serves as the core concept for all launches. When a rocket ignites on the launchpad, it expels exhaust downward at incredible speeds. This downward force creates an equivalent upward thrust, propelling the vehicle toward the sky. On a smaller scale, this same principle can be observed in a physics demonstration where firing a fire extinguisher pushes the person holding it in the opposite direction. This mechanical process is what allows a spacecraft attached to a rocket to leave the ground. The exhaust shoots toward the launchpad as it leaves the base. This principle was famously demonstrated by former MIT professor Walter Lewin during his farewell lecture.

However, simply moving upward is not enough to reach space. A spacecraft must achieve enough velocity to overcome the curvature of spacetime. According to general relativity, mass—such as that of the Earth—causes the fabric of the universe to curve inward, creating a funnel-like shape. Gravity, one of the four fundamental forces of the universe, is essentially this bending of spacetime. To escape Earth's pull, a rocket must move fast enough to climb out of this gravitational well. The gravitational force is one of the four fundamental forces in our universe. It is what makes moving up the funnel harder than moving down. Scientists use these concepts to understand how we can eventually reach outer space.

Achieving this requires the mastery of trajectories—the science of 'yeeting' objects into space with pinpoint accuracy. This involves balancing the intense g-forces experienced during acceleration against the need for precise orbital mechanics. It is a complex interplay of engineering and physics designed to transition from the heavy pull of Earth's surface to the weightlessness of an interstellar road trip. This journey involves transitioning from intense g-forces into a state of weightlessness. Astronaut Wendy B. Lawrence experienced this firsthand during the STS-67/ASTRO-2 mission in March 1995. The process requires many moving parts and significant hard work beyond just funding.

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