Interstellar Travel

[TMac3000]

Reading Sorpendarin's thread made me a little curious...just how would one go about performing an interstellar launch? I don't assume you would just point at the target star and burn...

 

[Sorpenderin]

do you mean in real life or in my project(when the first release comes out)?

 

[garyw]

Have a look at the Centauri Dreams website and the Icarus project

There is a lot of material on both sites about potential interstellar options including using the gravitational focus of a star at 500AU for comms satellites, best speeds for target star flyby and how to pick a target star.

The starship pictured on the front page of the icarus project might be familiar.

 

[Jarvitä]

Reading Sorpendarin's thread made me a little curious...just how would one go about performing an interstellar launch? I don't assume you would just point at the target star and burn...

At meaningful velocities, that's precisely what you'd do. If you're going fast enough, you can disregard orbital mechanics and treat it as a linear position-velocity-acceleration problem. If your speed is measured as a double-digit fraction of c, that is the case.

 

[TMac3000]

do you mean in real life or in my project(when the first release comes out)?

Real life

---------- Post added at 09:30 AM ---------- Previous post was at 09:25 AM ----------

I take it there would be no need for a launch window then? You just point and go?

And adjusting your trajectory to reach a particular planet in the target system would be a little tricky, much like trying to do a direct insertion to Europa without entering a parking orbit around Jupiter...

 

[garyw]

I take it there would be no need for a launch window then? You just point and go?

No idea about that but as it's solar escape I'd guess it's a point and go as well.

And adjusting your trajectory to reach a particular planet in the target system would be a little tricky, much like trying to do a direct insertion to Europa without entering a parking orbit around Jupiter...

You wouldn't. You'd use robotic probes to get a closer look. The interstellar ship itself would cruise right through the target solar system in something like 72 hours.

 

[Jarvitä]

I take it there would be no need for a launch window then? You just point and go?

And adjusting your trajectory to reach a particular planet in the target system would be a little tricky, much like trying to do a direct insertion to Europa without entering a parking orbit around Jupiter...

Let's assume a very modest cruise speed of 0.05c, which is ca. 15 000 km/s. The total dV of the vessel would then need to be at least 30 000 km/s if you plan on stopping at the destination. Do you really think spending a few dozens of km/s for precise orbital ejection /insertion on either end makes much of a difference?

 

[Izack]

And adjusting your trajectory to reach a particular planet in the target system would be a little tricky, much like trying to do a direct insertion to Europa without entering a parking orbit around Jupiter...

At 100AU (relatively speaking right on Ups And's doorstep) and 0.12c it was no problem at all to insert precisely into a gas giant's SOI. Starships tend to have an abundance of both [math]\Delta v[/math] and manoeuvring lenience.

 

[jedidia]

And adjusting your trajectory to reach a particular planet in the target system would be a little tricky, much like trying to do a direct insertion to Europa without entering a parking orbit around Jupiter...

You ca try ot for yourself how tricky it is using Orbiter Galaxy. However, most of the trickyness in Orbiter comes from the lack of appropriate navigational tools. With professional burn slutions, this shouldn't be any trickier than launching spirit to mars in practically one go with direct entry...

 

[sorindafabico]

Reading Sorpendarin's thread made me a little curious...just how would one go about performing an interstellar launch? I don't assume you would just point at the target star and burn...

According to Project Longshot, you have to put the spacecraft on a solar orbit with the inclination of the target star (Alpha Centauri : 61 degrees relative to the ecliptic to get RInc = 0) before the "trans-stellar burn". The method is the same of interplanetary travel, but with bigger budget.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890007533_1989007533.pdf

 

[dumbo2007]

And how do I get into a solar orbit ? or do plane change once in orbit ?

 

[sorindafabico]

To get into solar orbit: escape from Earth sphere of influence (or another planet's SOI). The planets themselves are on solar orbits.

Plane change: wait for the node between planes and do a burn on normal +/- orientation (the same method of LEO or interplanetary travel). An orbital plane change would be required in Project Longshot because the spacecraft would be assembled at SS Freedom/ISS.