ASTRO-110 Lecture Notes - Lecture 23: Interstellar Travel, Pioneer 10, Escape Velocity
9 Sep 2020
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Humanity has 4 probes travelling away from the solar system: pioneers 10 and. 11, and voyagers 1 and 2 the first to attain escape velocity from the solar system. Pioneer 10 took 21 months to reach jupiter. Nearest star, alpha centauri, is 70,000 times further away 115,000 years! The cosmic speed limit: c = 300,000 km/s (speed of light) 8. 8 years for round-trip to alpha centauri. As you get closer to the speed of light, your mass increases! Accelerating a 5000-person spaceship to 10% of c requires ~4. 5 * 1022 joules ~100 times current annual energy use. Chemical rockets fuel is a mixture of oxygen and kerosene. To attain escape velocity from earth, 11 km/s, a rocket needs fuel that weighs 38 times the rest of the rocket (payload) Mass ratio is 39 (38 + 1 : 1) But our best rockets have mass ratios of 15 or less. Saturn v was most powerful rocket ever built.
