50 minutes ago, dmwalker said:

20% of light speed seems popular

Magic engines.....

Don't forget the mass of the fuel needed get to that speed and then slow down.

Because of course the more fuel you carry, the more fuel you need to accelerate that fuel etc etc

Not unsolvable, but it's a nasty problem until you get those magic sci-fi engines.

With chemical rockets for instance, the amount of fuel needed to reach 99c would probably weigh about the same as Earth.

Other propulsion systems have their own issues.

16 minutes ago, HiFlyer said:

but it's a nasty problem until you get those magic sci-fi engines

A couple more major breakthroughs should get us there. Breakthrough meaning a practical demonstration, on a human scale, of a journey to Mars, rather than something microscopic in a laboratory.

2 hours ago, dmwalker said:

A couple more major breakthroughs should get us there. Breakthrough meaning a practical demonstration, on a human scale, of a journey to Mars, rather than something microscopic in a laboratory.

Probably one of the more do-able drive systems within our (Kinda) tech level would be something like the Orion project; dumping nukes out the back and letting the explosions push us to the stars.

But I remember even as a kid thinking the idea, even if possible, was was rube-goldberg wacky.

The once-secret test footage demonstrating the concept still strikes me as kids playing with explosives in the backyard, while mom and dad are away....

I think I remember reading that it would take us blowing up a couple of thousand nukes to get to Alpha Centauri.

 

Edited November 14, 20232 yr by HiFlyer

55 minutes ago, HiFlyer said:

Probably one of the more do-able drive systems within our (Kinda) tech level would be something like the Orion project; dumping nukes out the back and letting the explosions push us to the stars.

"Project Orion was a study of a starship intended to be directly propelled by a series of explosions of atomic bombs behind the craft (nuclear pulse propulsion)

The project was eventually abandoned for multiple reasons such as the Partial Test Ban Treaty which banned nuclear explosions in space as well as concerns over nuclear fallout.

The biggest design was the "Super" Orion design; at 8 million tons, 7250000000 Kilograms it could easily be a city.

 One design proposed by Freeman Dyson for the "Super Orion" called for the pusher plate to be composed primarily of uranium or a transuranic element so that upon reaching a nearby star system the plate could be converted to nuclear fuel."

 

Edited November 14, 20232 yr by dmwalker

4 hours ago, HiFlyer said:

Probably one of the more do-able drive systems within our (Kinda) tech level would be something like the Orion project; dumping nukes out the back and letting the explosions push us to the stars.

But I remember even as a kid thinking the idea, even if possible, was was rube-goldberg wacky.

As I recall, I first remember reading A.E. van Vogt's novel "Empire of the Atom" around 1960. His book was released in 1956. Another to mention the concept of the Orion Engine were Jerry Pournelle and Larry Niven in their novel "Footfall."

Robert Heinlein however was among my favorite sci-fi authors and I was particularly influenced by his short story "Blowups Happen!"

17 hours ago, n4gix said:

Another to mention the concept of the Orion Engine were Jerry Pournelle and Larry Niven in their novel "Footfall."

And the scary part is that the real life Orion would have been just as lethal as the one in the book, if not moreso......