of the rocket, based on Goddard's belief that the rocket would achieve stability by "hanging" from the engine like a pendulum in flight. However, the rocket veered off course and crashed away from the launch site, indicating that the rocket was no more stable than one with the rocket engine at the base. Uses Rockets or other similar reaction devices carrying their own propellant must be used when there is no other substance (land, water, or air) or force (gravity, magnetism, light) that a vehicle may usefully employ for propulsion, such as in space. In these circumstances, it is necessary to carry all the propellant to be used. However, they are also useful in other situations: Military Some military weapons use rockets to propel warheads to their targets. A rocket and its payload together are generally referred to as a missile when the weapon has a guidance system (not all missiles use rocket engines, some use other engines such as jets) or as a rocket if it is unguided. Anti-tank and anti-aircraft missiles use rocket engines to engage targets at high speed at a range of several miles, while intercontinental ballistic missiles can be used to deliver multiple nuclear warheads from thousands of miles, and anti-ballistic missiles try to stop them. Rockets have also been tested for reconnaissance, such as the Ping-Pong rocket, which was launched to surveil enemy targets, however, recon rockets have never come into wide use in the military. Science and research Sounding rockets are commonly used to carry instruments that take readings from to above the surface of the Earth. The first images of Earth from space were obtained from a V-2 rocket in 1946 (flight #13). Rocket engines are also used to propel rocket sleds along a rail at extremely high speed. The world record for this is Mach 8.5. Spaceflight Larger rockets are normally launched from a launch pad that provides stable support until a few seconds after ignition. Due to their high exhaust velocity——rockets are particularly useful when very high speeds are required, such as orbital speed at approximately . Spacecraft delivered into orbital trajectories become artificial satellites, which are used for many commercial purposes. Indeed, rockets remain the only way to launch spacecraft into orbit and beyond. They are also used to rapidly accelerate spacecraft when they change orbits or de-orbit for landing. Also, a rocket may be used to soften a