return async env => {
  let navbar = await _require('/navbar.jst')

  await navbar(
    env,
    // head
    async _out => {},
    // body
    async _out => {
      h1 {'Space Shuttle Program'}

      p {'The Space Shuttle was designed as a reusable spacecraft, which was originally intended to be able to fly 24 times a year, with a cost of only $20 million per flight. Unfortunately, the Space Shuttle never came near to NASA’s targets, and was only partially reusable.'}

      p {'The Space Shuttle consisted of 4 parts; the orbiter, two Solid Rocket Boosters (SRBs) and the external fuel tank. The orbiter contained the crew and anything else needed for the mission. It was the most reusable. The SRBs contained solid fuel and provided most of the power to leave the Earth’s atmosphere. After doing so, they disconnected from the rest of the shuttle and used parachutes to fall back to the Earth’s surface, where they were recovered and refurbished. The external fuel tank held liquid fuel which powered the 3 main engines of the orbiter. Once the fuel was finished, the external fuel tank was disattached from the orbiter and burned up in the Earth’s atmosphere, making it the only one-use part of the spacecraft.'}

      img.center-block(src="/images/space_shuttle_diagram.png" height="600px") {}

      p {'To get back to Earth is a different matter. To slow down from its approximately 27,000 km/h orbiting speed, the orbiter used friction created by the Earth’s atmosphere. First, it used its other engines called Orbital Maneuvering System (OMS) Engines, which were much smaller than the main ones, and had less than 1% of the power. The fuel for the OMS engines is stored onboard. The orbiter orbits backwards, so the first step to get down to Earth was the deorbit burn, slowing it down enough for it to start spiralling downwards. The orbiter is turned the right way up, and the computers onboard calculate the angles that it needs to be on to land on NASA’s 4.5 km run way. The changes in angle are executed by the OMS Engines.'}
    },
    // scripts
    async _out => {}
  )
}