Most rockets are launched from spaceports located near the equator to take advantage of Earth’s rotational force, significantly increasing speed and reducing fuel consumption.
If you have followed a recent rocket launch, whether from NASA, SpaceX, or the China National Space Administration, you will notice some similarities in both the launch sites and the shape of the rockets. The reasons behind these similarities relate to safety for the public and launching rockets into space with minimal effort, according to IFL Science.
Ariane 5 rocket launched from French Guiana, just 500 km from the equator. (Photo: ESA).
Firstly, the launch site must be near the ocean. The first few minutes after launch are critical. If a rocket launch fails, it is better for it to fall into the open ocean rather than a densely populated area. Some spaceports, like Baikonur in Kazakhstan, are not near the sea, but the rocket’s trajectory does not pass over populated areas.
Another less obvious requirement for a launch site is the latitude of the spaceport. NASA’s Kennedy Space Center in Florida is located at 28 degrees north latitude. SpaceX’s Starbase is at 25 degrees north. The Wenchang Space Launch Site is at 19 degrees north. The European Space Agency’s (ESA) center in Guiana is at 5 degrees north. The reason for this common characteristic is that rockets can more easily reach space with assistance from Earth.
At the equator, the Earth rotates at 1,650 km/h relative to the planet’s center. The closer to the equator, the less fuel is needed to reach space because this rotational speed can be utilized. Traveling into space requires substantial velocity. Due to the Earth’s rotation around its axis, launching from where the Earth is widest, at the equator, significantly boosts acceleration, according to ESA. ESA is set to launch the new Ariane 6 rocket for the first time from the Guiana Space Centre next week. Launching near the equator means that the rocket will begin its ascent at 5% of the speed needed to reach orbit. While this may seem negligible, it can drastically reduce fuel consumption, significantly increasing payload capacity.
The Russian Soyuz spacecraft previously launched from the Guiana Space Centre before the Russia-Ukraine conflict erupted. Currently, Soyuz rockets continue to launch from Baikonur at 45 degrees north. The Soyuz rockets launched from the equator carry over 60% more cargo than those launched from Kazakhstan.
However, this rule has exceptions and is not solely influenced by geopolitics. Some spaceports are located further north as they do not require additional speed enhancement. Launching near the equator is very advantageous for many orbits, but not all. Polar orbits, such as Sun-synchronous orbits or Molniya orbits for studying higher latitudes, are examples of such exceptions.
