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Comment by jimbokun | Hacker News Reader

In this book, a space flight to Alpha Centauri uses an asteroid which is constantly accelerated at 1g for half the flight, then constantly decelerates at 1g for the second half of the trip:

https://en.wikipedia.org/wiki/The_Sparrow_(novel)

That eliminates need for "artificial gravity" and really drove home to me that 1g is really the limiting factor for long range human space flight.

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1g isn't all that limiting. Under 1g acceleration you'll reach lightspeed in about a year, at which point you can't go any faster. A year to reach the top speed of the universe isn't so bad.

The truly limiting factor is that we don't have engines that can produce 1g for a sustained period. We can't carry and propel enough reaction mass and reactionless drives only exist in science fiction.

> you'll reach lightspeed in about a year, at which point you can't go any faster

I don't think that's how relativity works?

assuming constant acceleration it kinda does, but constant acceleration requires asymptotic infinite amounts of energy.

As measured relative to the destination, yes, but if so then that means the passengers get crushed under infinite gs.

It would have been better phrased "at which point you can't go any faster relative to the departure location".

Yup, it would take 6 years instead. Ship time ;)

Source: https://gregsspacecalculations.blogspot.com/p/blog-page.html... and ignoring all the other fun aspects.

That’s just what it shows after rounding up. The site correctly doesn’t let you enter 1c for velocity since it’s not possible.

Love that book.

I love it and hate it. Beautiful and brilliant, and combines religion with sci-fi without demonizing the religious characters.

But events later in the book, while completely consistent with the premise, were pretty gut wrenching to read.

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