Mars in 3 days

[AngelLestat]

the biggest problem with long range beaming, is accuracy and diffraction.
Even with huge fresnel lenses (at jupiter distance) to focus the beam, it is no enough to the grade of magnitude that we need. 
As I said.. a light solar probe can accelerate very fast without laser, and brake in the target star using the same maneuver.
That is the most easy and cheaper way to do an interstellar travel.
It may require a lot of test and mastering in the tech, but these sails can be so light and cheap that would no matter how many times you test this to achieve an improvement in each step. 

[Bill Phil]

12 hours ago, Spaceception said:

Ooooh, green Stars, I didn't know those existed

There are, it's just that there's a whole bunch of other colors that bleed over. Our sun would be green, if not for the plethora of other colors that we can't differentiate.

ROYGBIV, right? Well, G, I, and V are all present, but indistinguishable.

[Spaceception]

6 minutes ago, Bill Phil said:

There are, it's just that there's a whole bunch of other colors that bleed over. Our sun would be green, if not for the plethora of other colors that we can't differentiate.

ROYGBIV, right? Well, G, I, and V are all present, but indistinguishable.

No, I mean visible light green stars

[fredinno]

16 hours ago, kerbiloid said:

Pictured that Super Starlight project where they stop and return.

 

I would like an explanation to this diagram. It is confusing.

 

20 hours ago, Stargate525 said:

If you're talking coming into a system at interstellar speeds, you could probably bleed some speed off by clever and numerous flybys. Or massive aerobraking.

Aerobraking would be a nightmare at relativistic speeds, with insane Gs (Galileo probe was 230G) and flybys would have little effect when you are travelling so fast.

[KAL 9000]

4 hours ago, Spaceception said:

http://www.amazon.com/gp/product/B00NERQRPI/ref=dp-kindle-redirect?ie=UTF8&btkr=1

That's what I meant.

[PB666]

On 2/26/2016 at 10:04 AM, Spaceception said:

NASA recently did research on a propulsion system that could get humans to Mars in as little as 3 days for a 100 kg probe, and a Manned (Much heavier) spacecraft in a month.

Now, we do know this tech exists, like Starwisp, but if they can scale up the lasers (And power) needed (With either massive solar panels, or fusion reactors), we could send a probe to Proxima Centauri by the end of the century, and have it get there in as little as 40 years.

Now, there's no telling of whether this would get enough funding (Or any funding), but if it did, we could have a very fast propulsion system that could allow us to explore to solar system quickly.

So what do you think about it? And do you guys think building something like this would be worth it?

Take human freeze to 50'K When they reach mars in 3 days and smash into the surface you won't know whether the freezing killed them or the fall.

 

[Bill Phil]

22 minutes ago, PB666 said:

Take human freeze to 50'K When they reach mars in 3 days and smash into the surface you won't know whether the freezing killed them or the fall.

 

Then freezing would kill them. Ice crystals would damage cells. Defrosting would be even worse.

[fredinno]

1 hour ago, Bill Phil said:

Then freezing would kill them. Ice crystals would damage cells. Defrosting would be even worse.

Maybe the human would be in cryofreeze|?

[PB666]

8 hours ago, Bill Phil said:

Then freezing would kill them. Ice crystals would damage cells. Defrosting would be even worse.

Yes but they would not be dead-dead until you thawed them out, but when they smacked mars at 2500 m/s their ice crystals would be blasted into martian dust. My point was thats the only way you are going to get a fully intact human to mars in 3 days. A radial trajectory, no life support (thats why they would have to be frozen), and a direct trajectory to intercept mars (basically shooting an orange with dart). To keep the human from shifting around simply freeze to below -50'C, insulate until in space. remove the fairing, bingo you have a frozen human payload (technically it would be a projectile).

@fredinno - there is no known way to cryofreeze the human nervous system, most of the cryoproctants are neurotoxic and to boot, there is not a 100% recovery of cells that are recovered from storage in liquid nitrogen.

[AngelLestat]

13 hours ago, fredinno said:

I would like an explanation to this diagram. It is confusing.

Maybe with this graph it will be easy to understand, this is an old Robert Forward idea for a 3 stage sail that can go and back using the same laser beam from earth.

Edited February 28, 2016 by AngelLestat

[Spaceception]

3 minutes ago, AngelLestat said:

Maybe with this graph it will be easy to understand, this is an old Robert Forward idea for a 3 stage sail that can go and back using the same laser beam from earth.

That looks like the sail is sailing to Epsilon Eridani.

[11of10]

Well, if this is viable, even for small probes, I guess it could practically open Solar system for us. I mean, even if you'd need 20 days to Mars with this, it's still incredibly better than whatever we have today. Send some infrastructure before the crew, and send the crew in a small craft just for them, and I guess you're on to something.

[AngelLestat]

On 28/2/2016 at 0:29 PM, Spaceception said:

That looks like the sail is sailing to Epsilon Eridani.

Yeah, the book is called the dragon fly or something like that..  from robert forward, they travel to epsilon eridani.
But that laser-lens 3 stage mechanic might be more practical for interplanetary transport, but even at these distances it will be an engineering nightmare on optics and scale.

[NuclearNut]

On 2/27/2016 at 8:54 PM, Stargate525 said:

And the power on Mars for such a laser is coming from...?

You could utilize multiple nuclear reactors on mars to generate the electricity needed to power the giant laser needed to move the ship.  The units would probably be fast reactors designed to breed fissile fuel from fertile material, reducing the cost to generate said fissile material.  These reactors would also need nowhere near the safety, waste disposal, and leak prevention systems as earth reactors due to the preexisting shielding requirements on mars, thus they could be created and operated at costs far, far lower than conventional earth based reactors.

Edited March 1, 2016 by NuclearNut

[Bill Phil]

On February 28, 2016 at 8:04 PM, Spaceception said:

No, I mean visible light green stars

Our sun is strongest in the green. It's visible light. But we can't differentiate.

[Spaceception]

Just now, Bill Phil said:

Our sun is strongest in the green. It's visible light. But we can't differentiate.

Oh, alright

[11of10]

You know... at this moment, you don't really need a Martian laser station. You just need to bring enough fuel to slow down the probe, or whatever it is you're sending, other than crews. In time, if there is need, I imagine interplanetary civilization could finance building of multiple such laser stations, sort of how the trains receive their power from the powerplant, and only use it, instead of making it, so could some future spacecraft work in similar manner.

Besides... you can always send a giant mirror to orbit Mars, and target it from here, to slow down your lightcraft with Earth's own laser station...

Just in the early days, of course

[Stargate525]

18 hours ago, NuclearNut said:

You could utilize multiple nuclear reactors on mars to generate the electricity needed to power the giant laser needed to move the ship.  The units would probably be fast reactors designed to breed fissile fuel from fertile material, reducing the cost to generate said fissile material.  These reactors would also need nowhere near the safety, waste disposal, and leak prevention systems as earth reactors due to the preexisting shielding requirements on mars, thus they could be created and operated at costs far, far lower than conventional earth based reactors.

Good luck hauling the equipment needed for a nuclear power station out to Mars. You know, several of these:

 

[NuclearNut]

6 hours ago, Stargate525 said:

Good luck hauling the equipment needed for a nuclear power station out to Mars. You know, several of these:

 

That is a PWR Pressure vessel for the VVER 1000.

 

PWR units are ill suited for extraplanetary utilization due to their high volume for their power output and inability to breed fuel without some extremely special (expensive) modification.  They also require high pressure forging in a specialized foundry, of which their are only a few ten such units on earth.  On mars there is none and it is probable that that will remain for quite a while after we establish a base.  Even if a PWR was utilized, it would still have a power density advantage over all other options.  Solar panels would weigh significantly more than a reactor for the same power output.

Instead we could utilize lead, sodium, or other cooled fast reactors.  The advantage to these reactors it that they can operate at low pressures, which is to say that they will not need a pressure vessel like a PWR would need.  They also do not need enrichment facilities, though reprocessing would be needed (probably pyroprocessing), and that I concede is a bit of a problem.  These reactors, again, due to the lack of a need for a PV, could also be made from locally sourced materials to a great degree, with concrete holding together the RV in a way similar to that of the Fort Worth NGS unit.  This could reduce the required shipments to just that of the inner lining for the RV and fuel to startup the reactor, presumably along with some fresh materials to produce fuel elements every so often.

Now mind, nuclear is definitely the most practical option for power generation on mars, but to imply that a laser sail is the most practical means of going to mars is, in my opinion, not entirely correct.  So while using nuclear energy to power the receiving laser is the most reasonable, using lasers is not so reasonable for the foreseeable future.