Spaceman Spiff is flying his rocket on patrol when he gets a distress call. An asteroid is on a collision course with a space station. The asteroid contains a newly discovered form of life, so Spiff must save both the asteroid and the space station. The easiest way to do this is to land his spaceship on the asteroid upside down so that the main rocket engines will point away from the asteroid. Spiff can then fire his engines and speed the asteroid up enough to that it will pass in front of the space station. If the asteroid has a mass of 18.5 Mkg, how much work Spiff’s rocket engines have to do if he wants to increase the asteroid’s speed by 23 km/s? How much work must his engines do if he decides it would be better to slow the asteroid down by 18.5 km/s?