Key Takeaways:
- Spacecraft possess the capability to significantly modify their speed and trajectory.
- Such alterations are achieved through maneuvers involving close proximity to a substantial celestial body.
- A notable characteristic of this technique is the absence of fuel consumption for propulsion during the alteration.
- Despite any appearance of being entirely without cost, this method is explicitly stated to not represent a "free lunch."
By passing near a large body, a spacecraft can radically alter its speed and trajectory without expending any fuel. This may sound like a free lunch, but it isn’t.
