阅读图片上的文字---**Article Content Extraction** **Title:** HOW REUSABLE ROCKETS WORK **Subtitle:** New launch vehicles that can fly multiple missions are transforming space travel **Author:** WORDS ANDREW MAY **Main Text:** Imagine if an airliner only lasted a single journey and a new one had to be built for every single flight. It may sound crazy, but in the world of spaceflight, this 'single-use' approach is a well-established practice. The first rockets to launch humans into orbit back in the 1960s were converted military missiles, so it's no surprise they were designed for just one flight each. For space operators like NASA, however, the result was painfully expensive. Adjusted to modern prices, the cost of putting a payload into orbit using one of those early rockets was around $30,000 (£23,700) per kilogram. The obvious solution was to make space launchers reusable, and NASA came up with just such an approach that it believed would drastically reduce launch costs. This was the Space Shuttle, which first flew in 1981. Unfortunately, the Space Shuttle pushed costs in the wrong direction. Despite its reusable design, it still managed to soak up $65,000 (£51,400) for every kilogram it delivered to orbit. The problem was that in order to achieve reusability with 20th-century technology, the Space Shuttle had to be very complicated. To bring it back in one piece, it had to be flown down through the atmosphere by human pilots, who then landed it on a runway like an aeroplane. The need for wings, landing gear and a crew is what made costs soar. A simpler solution would have been to use something resembling those first-generation rockets, bringing them back down to a precision landing under computer control without the need for a crew. To the Space Shuttle's designers, this would have seemed unthinkably far-fetched - yet it's exactly what SpaceX does today, on a routine basis, with its Falcon 9 rockets. These have ushered in a new age of 'cheap' space travel, at least in relative terms, with the cost of launch now down to just $2,000 (£1,580) per kilogram. While SpaceX is the current leader in reusable rocketry, other companies such as Blue Origin and Rocket Lab are developing similar systems of their own. **Tech Specs Box:** TECH SPECS FALCON 9 Launches in 2024: 134 SPACE SHUTTLE Total launches: 135 SPACEX STARSHIP Height: 121 metres BLUE ORIGIN NEW GLENN Payload to orbit: 45 tonnes ROCKET LAB ELECTRON Cost per launch: $7.5 million (£5.9 million) **Pros and Cons Box:** PROS AND CONS OF REUSABILITY Aside from economic considerations, reusable rockets have environmental benefits, as they create less space junk. But they have disadvantages too. They're more complex systems due to the need for retractable control fins and landing legs, and they have to go through a meticulous refurbishment process after each launch. This means the real benefits of reusability are only seen when large numbers of launches are required. This is true of SpaceX, which needs to launch thousands of small satellites every year. Significantly, other companies focusing on launcher reuse are also in the satellite launch business. At the other extreme, organisations like the European Space Agency (ESA), which specialises in small numbers of sophisticated science missions, may only need a handful of launches per year. For them, single-use rockets remain the most sensible choice. **Diagram Description: Falcon 9 Launch and Recovery** Type: Illustrated diagram showing the stages of a rocket launch and recovery process. Main Elements: - Background: Depicts the ground (possibly desert) and the sky with stars and Earth's curvature visible higher up. - Rocket Stages: A multi-stage rocket is shown in various positions indicating ascent and stage separation. - Labels and Annotations: - Label 1 (bottom): Points to the base stage of the rocket on the launch pad. Text: "FIRST STAGE This is the reusable part of the launch rocket, also referred to as the 'booster'." - Label 2 (above 1): Points to the section above the first stage. Text: "UPPER STAGE This is a smaller rocket stage that carries the payload into orbit, but isn't recoverable." - Label 3 (mid-ascent): Points to the entire rocket structure during ascent. Text: "ASCENT PHASE The booster engines fire at full thrust to carry the rocket most of the way to orbit." - Label 4 (higher up, separation point): Points to the rocket structure just after the lower stage has detached. Text: "STAGE SEPARATION Once above the atmosphere, the booster separates. The second stage and payload continue into orbit." - Title below diagram: "FALCON 9 LAUNCH AND RECOVERY Here's how SpaceX retrieves its booster rockets so they can be reused". **Other Image Caption:** An image of the Ariane 6 rocket in space with a caption: "Despite being a modern rocket that first flew in 2024, the Ariane 6 isn't reusable". **Page Number:** 38

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