Propulsion Systems
Overview
The Eridani system is 10.5 light years (i.e. 664 036.189 AU) distant from the solar system. As a comparison, the Voyager 1 spacecraft launched on September 5th 1977 which is the most distant active spacecraft has traveled about 116 AU. Sending a spacecraft at such a distance is very challenging and requires a meticulous choice of the propulsion system.
So far, the spacecraft velocity in previous interplanetary missions has roughly reached 50 km. s-1. As an example, if we assume that Space buster travels at 5,000km.s-1 on average, the voyage time will last about 630 years. The interstellar voyage may be divided into three phases:
- Phase 1: travel in the solar system (230 AU)
- Phase 2 : travel between the two systems (663 500 AU)
- Phase 3 : travel in the Eridani system(150AU)
Space buster has to carry substantial propulsive capability to reach move away the Sun attraction (phase1) as well as decelerate (phase3) at the right moment to achieve orbit insertion in the Eridani system. During the intersystem travel, even though the distance accounts for more than 99% of the total distance traveled, the propulsion system is only required to control and correct the trajectory since the celestial bodies’ attraction is less important than in Phase1 and 3.
Furthermore, the trajectory choice also plays a significant role to select the propulsion system. Indeed, there exist very fuel saving trajectories called slingshot trajectories which use of the relative movement and gravity celestial bodies to alter the path and speed of a spacecraft. For instance, Voyager 1 does not use propulsion system but this gravity-assist trajectory to keep a high speed motion. The next part is devoted to analyze the feasibility of such a trajectory for the interstellar voyage based on the Voyager 1 slingshot trajectory.