Mombasa Tether
From Halopedia, the Halo wiki
The New Mombasa Orbital Elevator is a massive Space Elevator located at the center of the city of New Mombasa on Earth. The elevator, which is the focal point for the city, stretches far into the planet's orbit. It is used for lifting heavy ordinance into the atmosphere of the planet using a pulley system that negates the use of rockets or waste of fuel to generate an escape velocity for materials.
In 2552, when the city was attacked by the Covenant during The First Battle of Earth, the Assault Carrier commanded by the High Prophet of Regret landed troops around the elevator. Eventually, it was destroyed when the Prophet initiated a slipspace jump inside the city, though it is unknown for how long the structure remained stable before it inevitably fell. Remains of the elevator crashed to the surface around a massive Forerunner structure thought to be the Ark.