- During the boost phase, it accelerates at a fixed rate. This phase is powered because the rocket is firing.
- During the cruise phase, it coasts at a fixed velocity. This phase is unpowered.
- During the deceleration phase, it decelerates at the same rate as it had originally accelerated. That is, deceleration phase is a mirror of the boost phase. This phase is also powered.
This page computes a number of interesting properties of such a trip, given just a few bits of information. Fill in what you know and it computes the rest.
Powered Phase Questions.
What is the acceleration?
Answer any one of the next five questions.
|How far does it travel under power?|
|How far does it travel during boost alone?|
|What velocity does it reach?|
|How long does it accelerate? (ship time)|
|How long does it accelerate (earth time)?|
Cruise Phase Questions.
Answer any one of the following six questions. "Total" in this section includes boost, cruise, and deceleration, so "total distance" is the entire distance from Earth to the star.
|What is the total distance travelled?|
|How long is the whole trip? (ship time)|
|How long is the whole trip? (earth time)|
|How far does it travel during cruise?|
|How long does it cruise? (ship time)||How long does it cruise? (earth time)|
At max velocity, time slows down and lengths contract by a factor, tau, while and mass increases by its reciprocal, gamma.
How much "time slip" is there between the crew and the people on Earth?
|Earth minus Ship Time|
How much reaction mass is needed, assuming we use anti-matter fuel and our exhaust is coherent gamma rays.
|Mass per kilogram to cruise velocity|
|Energy per kilogram to cruise velocity|
|Mass per kilogram to destination|
|Energy per kilogram to destination|
Suppose there were no such thing as relativity. What would the times look like? (For cruise segments, this keeps the distances constant.)
|Newtonian Boost Time|
|Newtonian Cruise Velocity|
|Newtonian Cruise Time|
|Newtonian Total Time|
Other relativity numbers. You should read the Relativistic Rocket (below) for explanations.
Link for sharing these calculations:
All calculations taken from the Relativistic Rocket (Don Koks and Phillip Gibbs, 2006)