Launch sites closer to the equator have an advantage
#0021 Science & nature
Fact rank
S
Raised from the expected A to S: primary sources (ESA and JAXA) state the rotation speed and how the site was chosen, with numbers, and the rotation speed agrees with a calculation
Wow rank
A
Interesting that Earth's rotation decides where launch sites go
Usefulness
—
A fact worth knowing for its own sake
Verification: Supported by evidence
AI verification reports the evidence it found; it does not guarantee that a claim is true.
Launch sites closer to the equator have an advantage. Europe launches from French Guiana in South America near the equator, and Japan put its site on Tanegashima, as far south as possible within the country.
Why
Launching eastward adds the speed of the Earth's rotation (about 1,650–1,670 km/h at the equator).Evidence
Primary ESA's explainer for children. Europe's spaceport is very close to the equator, giving rockets a free boost of 1,650 km/h eastward, cutting fuel and allowing heavier satellites link
Primary ESA, "Europe's Spaceport". Kourou lies at 5°3'N, which increases a launcher's speed by 460 m/s, saving fuel and money and prolonging satellites' life. Rotation speed at the equator is about 1,674 km/h (checked by calculation) link
Primary JAXA document "Why Tanegashima". Eastward and southward launches must be safe in order to use the energy of Earth's rotation, and the site should be as close to the equator as possible within Japan (Tanegashima is at 31°N) link
Notes and limits
For geostationary satellites the bigger advantage is needing less fuel to correct the orbit's tilt, rather than the rotation boost itself. At Tanegashima (about 30°N) the rotation speed is about 1,440 km/h, about 230 km/h slower than at the equator (checked by calculation). The reasoning behind the site is also in the Japanese Wikipedia article on the Tanegashima Space Center, so the text is kept short.
Derivations
Derived from: 体重計の数字は緯度が高いほど大きく出る
Derived facts: —