「ロケットの射場は赤道に近いほど有利/en」の版間の差分

2026年10月29日 (木) 19:34時点における最新版

#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

Posted by: Mamechi editors ・ Verified: 2026-10-29 ・ Method: AI + human ・ On Wikipedia?: Already on Wikipedia

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: —

@@ 2行目: / 2行目: @@
 {{豆知識
 |番号=0021
-|本文=Launching a rocket eastward adds the speed of the Earth's rotation (about 1,650–1,670 km/h at the equator), so 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.
+|投稿者=まめち編集部
+|本文=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.
+|なぜ=Launching eastward adds the speed of the Earth's rotation (about 1,650–1,670 km/h at the equator).
 |ジャンル=科学・自然
 |ファクト度=S