When is the launch window to send a probe to Andromeda?

When is the launch window to send a probe to Andromeda? Since our sun orbits with the Milky Way Galaxy every 200 million years, I'm assuming every 200 millions years there's a best time to send an unmanned probe to the Andromeda Galaxy. What year would that be? How do you know?|||Andromeda is at coordinates Dec = 41 degrees, HA = 0h 45m (11 deg)


The center of the milky way is at Dec = -29 degrees, HA = 17h 45m (256 deg = 360 - 104).





Imagine a standard 12-hour clock face, with the center of the milky way at the center. The Earth is at 12:32. Andromeda is in the direction of 2:38. Andromeda is about 2,500,000 light years away, while the milky way center is about 25,900 light years. The Earth orbits around the galaxy counterclockwise. So it needs to go around for 167 million years to get to the point where Andromeda is closest. You would want to start about 50 million years before that, to take advantage of the rotational speed.





But why wait 117 million years? Any reasonable probe is going to travel at at least 1% light speed, just to make the trip in less than 250 million years. Adding 0.52 million years doesn't seem worth worrying about. If the probe could reach 10% light speed, it would take 25 million years, and starting at the "wrong" time would add only 0.052 million years. Waiting for the natural rotation of the galaxy for the Earth to get to the "right" place mean waiting 117 million years. That would be like waiting over a hour for a bus to come along, just so you could take the bus for a trip of 1 foot!





By the way, any probe that could last in space for 25 million years is going to have to be smarter than all of today's human civilization. So it might as well be manned. It will be a few 1000 years before we humans have the technology to build such a thing. By that time, the distinction between humans and robots may be hard to see.





|||Interesting question that assumes


1) Andromeda does not lie above the Galactic plane prependicular to centre in which case no diff


2) Won`t make any difference anyway as if we can make intergalactic distances any Galactic distance in crossing Milkt Way will be suburban travel on an Inter city voyage.|||By the time the Earth and Andromeda reaches it's closest distance, we would already have the ability to bypass the speed of light for faster than light travel.|||Wait 2 or 3 billion years for the closest approach.|||The delta-vee is a fairly constant 330 km/sec from nearly every point on the Sun's orbit around the galactic center.