# The Naked Scientists Forum

### Author Topic: What would be the transit time to Mars with unlimited power?  (Read 1044 times)

#### Semaphore

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##### What would be the transit time to Mars with unlimited power?
« on: 28/09/2016 16:04:10 »
It's going to be very difficult to protect astronauts from radiation during a trip to Mars, so what is the shortest transit time based on a very powerful drive, say a fusion drive? That would assume accelerating and decelerating at, say, 2g, or whatever load people could deal with on a constant basis. I suppose relativistic effects would kick in.

#### alancalverd

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #1 on: 28/09/2016 17:54:40 »
s = 0.5 a t^2 where s = distance, a = acceleration and t = time (you did that at school, surely?)

Minimum transit distance is probably 10^11 meters. Put a = 20 m/s^2 (a bit more than 2g) then t^2 = 10^10 so t = 10^5 seconds, just over a day.

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #2 on: 28/09/2016 18:04:06 »
s = 0.5 a t^2 where s = distance, a = acceleration and t = time (you did that at school, surely?)

Minimum transit distance is probably 10^11 meters. Put a = 20 m/s^2 (a bit more than 2g) then t^2 = 10^10 so t = 10^5 seconds, just over a day.

You don't need to be sarcastic.

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#### chiralSPO

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #3 on: 28/09/2016 18:42:23 »
s = 0.5 a t^2 where s = distance, a = acceleration and t = time (you did that at school, surely?)

Minimum transit distance is probably 10^11 meters. Put a = 20 m/s^2 (a bit more than 2g) then t^2 = 10^10 so t = 10^5 seconds, just over a day.

I assume that the OP intended on landing on Mars, not whizzing by it, or creating a new impact crater on its surface...

If one wanted to accelerate at 20m/s2 until the half-way point, and then decelerate at the same rate until the destination is reached, then just double the time it takes to get to 5x1010 meters.

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#### alancalverd

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #4 on: 28/09/2016 22:06:20 »

You don't need to be sarcastic.

True, but it's one of life's rare pleasures for an old man!

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #5 on: 28/09/2016 22:17:50 »
s = 0.5 a t^2 where s = distance, a = acceleration and t = time (you did that at school, surely?)

Minimum transit distance is probably 10^11 meters. Put a = 20 m/s^2 (a bit more than 2g) then t^2 = 10^10 so t = 10^5 seconds, just over a day.

I assume that the OP intended on landing on Mars, not whizzing by it, or creating a new impact crater on its surface...

If one wanted to accelerate at 20m/s2 until the half-way point, and then decelerate at the same rate until the destination is reached, then just double the time it takes to get to 5x1010 meters.

Thanks for correcting this guy's post.

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #6 on: 28/09/2016 22:20:20 »

You don't need to be sarcastic.

True, but it's one of life's rare pleasures for an old man!

That doesn't excuse it. I suppose you could have learned manners at school.

#### jeffreyH

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #7 on: 28/09/2016 23:52:56 »

You don't need to be sarcastic.

True, but it's one of life's rare pleasures for an old man!

That doesn't excuse it. I suppose you could have learned manners at school.

Alan will supply an answer to a science question without resort to wikipedia and it will be right. So giving him a little indulgence is well worth it.

#### alancalverd

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #8 on: 29/09/2016 08:40:14 »
I suppose you could have learned manners at school.

Physics and chemistry makyth Man. And I'll give you full marks for a good question.

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#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #9 on: 29/09/2016 15:03:24 »
So it takes 70711 seconds or 19.6 hours to get to the midway point and a similar time to decelerate, for a total of 1 day and 15 hours.

#### chiralSPO

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #10 on: 29/09/2016 15:20:10 »
So it takes 70711 seconds or 19.6 hours to get to the midway point and a similar time to decelerate, for a total of 1 day and 15 hours.

That sounds about right.

#### alancalverd

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #11 on: 29/09/2016 19:31:05 »
As they say at NASA, rocket science is ridiculously easy. Rocket engineering is the problem.

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #12 on: 29/09/2016 20:14:03 »
I suppose no one has thought about why I asked the question in the first place? Apart from my lack of education.

#### chiralSPO

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #13 on: 29/09/2016 20:29:37 »
Perhaps it is related to Elon Musk's recent announcement that SpaceX is planning on sending people to Mars?

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #14 on: 29/09/2016 20:34:13 »
Perhaps it is related to Elon Musk's recent announcement that SpaceX is planning on sending people to Mars?
And?

#### chiralSPO

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #15 on: 29/09/2016 21:36:10 »
...and you have a fusion powered super-rocket that you're wondering what to do with?

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #16 on: 30/09/2016 18:49:47 »
I think we should make sure we have the right equipment before we start this adventure, otherwise people will die, either from accidents or cancer. There are plenty of things that need fixing here before we start wrecking another planet. You don't need me to identify them.

#### Bill S

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #17 on: 30/09/2016 21:36:06 »
Quote from: Semaphore
You don't need me to identify them.

You could flag up a few for us!

Making silly comments is another "of life's rare pleasures for an old man!".

#### Semaphore

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##### Re: What would be the transit time to Mars with unlimited power?
« Reply #18 on: 30/09/2016 21:50:14 »
Quote from: Semaphore
You don't need me to identify them.

You could flag up a few for us!

Making silly comments is another "of life's rare pleasures for an old man!".

That's a pretty silly comment, tbf. Do you have anything to say about the issue?

#### The Naked Scientists Forum

##### Re: What would be the transit time to Mars with unlimited power?
« Reply #18 on: 30/09/2016 21:50:14 »