Project Hail Mary post release thread (open spoilers)

[robby]

@Frazzled

As I recall from the book, they had a constant 1.5g acceleration the whole way. Or more specifically halfway, then they turned around and decelerated at 1.5g for the remainder of the trip.

That may well be so. I don’t actually recall if there was any coasting in the middle. But it makes sense that they would. At a constant acceleration of 1.5G, you would reach 90% of the speed of light in less than 8 months (ignoring relativistic effects, which I know you can’t do). So at some point, you reach a point of diminishing returns as you approach the speed of light, by expending energy while not achieving any appreciable greater velocity.

So for a journey of nearly 12 light years, it makes sense that the ship would accelerate to some large fraction of the speed of light, coast for several years at that speed, then turn around and decelerate.

Unless I’m missing something.

[Chronos]

Continuing to accelerate wouldn’t make much difference in when the solution could get back to Earth. But it would make a difference in how long you have to keep life support working on the mission.

[robby]

@Chronos

Continuing to accelerate wouldn’t make much difference in when the solution could get back to Earth. But it would make a difference in how long you have to keep life support working on the mission.

Very good point! More acceleration doesn’t get the ship to its destination significantly faster, but you do get more time dilation.