Welcome To Your First Day As A (Sublight) StarShip Pilot - Course Notes

Introduction

Okay, the title is a bit tongue-in-cheek. What I want to do is write a post about how to navigate a space ship that is able to approach the speed of light but does not have any fancy sci-fi shields.

You may want to see my related post on sub-light space travel on how people can get to the next star without dying of old age.

The problem that needs to be solved is when you are traveling at such extreme velocities even a small pebble could destroy your star ship and kill you and everyone on board if you collide with it.

The Proposal

_{The green circle is Earth. The grey oval is our starship. The blue dots are radar stations. The blue dashes are the radar pings. The red dots are space rocks. The yellow circle is Alpha Centauri. The arrows are the velocity vectors.
(Image Credit: Me, I did this. Feel free to mock my artistic skills in the comments)}

So how do you get from one star to the next without hitting something and dying? The answer is to set up a string of powerful radar stations like pearls on a string from one star to the next. This is the future and I am going to assume that they are powerful enough and sensitive enough to pick up millimetre size specks of rock.

If each radar station could scan a radius of one light-day then it could cover a diameter of 2 light-days. Each day it would scan its volume and record both the position and the velocity of each asteroid, rock and particle. It would put this in a database and transmit the data back to Earth and/or the nearest star ship.

You would only need about 800 radar stations set up between Earth and Alpha Centauri (this is the future so I am going to assume that they can do this).

My illustration above shows a star ship at very high velocity traveling from Earth to Alpha Centauri. It is depicted as an oblate circle due to the significant length contraction you get at near light speeds.

At the time of launch the star ship would download the latest hazard database and set off.

The database would be out of date because it takes time for light to travel so it will have to continually update the database as it travels along its route. The ship will therefore always have the latest information on the hazards in its path and would be able to make the necessary course corrections to avoid disaster.

For instance:

• Space Rock 1 in the diagram is approaching the path of the star ship but won't cross its path before the ship gets near it so no worries there.
• Space Rock 2 on the other hand will cross the path of the star ship. The ship will probably know this at the time of setting off since rocks don't move fast compared to the large scan radius of the postulated radar station.
• Space Rock 3 is out of radar range but moves to within radar range during the star ship's journey. However, no worries because the star ship will find out about it during a mid-journey database update and then make any adjustments that are necessary on the fly.

In Closing

I have always wondered just how you could get to another star without some random pebble killing you if you are moving close to the speed of light.

Having a long string of radar stations that detect all of the hazards seems to be the way to go. Now all we need is an inexhaustible supply of energy to get our star ship up to near-light speeds. Easy-peasy.

Thank you for reading my post. Have a nice day.