With a sling-shot effect...just like visiting planets - only on a larger scale...
http://www.newscientist.com/article/dn26711-stars-flying-visit-could-fling-comets-at-earth.html#.VNNhUNSwWJR

A plan is in motion...we JUST have to WAIT for the RIGHT MOMENT!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

YES, YES...we wait! ;)

if don't come up with WARP drive...then we might need the slingshot of the inner planets & get the colonisation ship to another system! ;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

Getting a gravitational assist has been used on several missions to the outer planets but that method will not provide the necessary velocity for sending humans to planets around other stars. And then there is the matter of slowing back down once the target has been reached. It takes as much energy to slow down from a given velocity as it took to reach that velocity since there is essentially no friction in space.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

I think if humans decide to make an interstellar trip with no radical new propulsion, they'll need a super efficient closed system of a huge generation ship that goes really slow and hundreds of years to get to the nearest habitable system. Or else a smaller ship but with cryogenics and very good automation and no moving parts that will wear out while the passengers are asleep. Either way, they'll probably need a ramjet kind of propulsion in order to reduce the starting mass and the refuel for the deceleration.

But I think there will probably no attempts at an interstellar mission until there is some new propulsion that can cruise at like 0.1 speed of light, because they'd have to first send an unmanned probe to look for habitable planets. And that probe mission would take hundreds of years to get to the destination, and years to send back data at light speed. The organization or the country that sends the probe might not even exist by the time the probe finishes its tasks, if it even makes it there.

Wonder if it's even possible for FTL or reactionless drive. Seems like you'd have to trick physics as we know it to make it possible, like a perpetual motion machine. Haven't heard anything new about that quantum vacuum microwave engine that somehow works.

Getting a gravitational assist has been used on several missions to the outer planets but that method will not provide the necessary velocity for sending humans to planets around other stars. And then there is the matter of slowing back down once the target has been reached. It takes as much energy to slow down from a given velocity as it took to reach that velocity since there is essentially no friction in space.

Well, if they design it with solar sails...& use the drive only for initial drop to the inner planets trajectory...then they deploy the solar sails which keep positive acceleration past Jupiter...

And if they get 0,1c...& another solar system come within 0,15c...that would mean only a few years of jurney - but WITHOUT RETURN!
Or maybe a longer return if they don't find inhabitable planets...

But also, solar sails can be used as a parashute - when they come to another system...deploy them beyond the outer planets & the deacceleration will begin...

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non-profit org. Play4Life in Zagreb, Croatia, EU

The nearest star is 4 light years away.

Exactly! Even at 0.1 LS it would take 40 years to get there, at 0.01 LS 400 years. We could well find that the civilisation we contacted doesn't exist any more. Unless we can develop faster than lightspeed drive, we ain't going anywhere! Manned spaceflight with solar sails is still firmly science fiction.

+1

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

Exactly! Even at 0.1 LS it would take 40 years to get there, at 0.01 LS 400 years. We could well find that the civilisation we contacted doesn't exist any more. Unless we can develop faster than lightspeed drive, we ain't going anywhere! Manned spaceflight with solar sails is still firmly science fiction.

+1

+2

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The other thing I wonder about is how would interstellar ships even properly aim themselves at the target system and planet. Star systems go around the galactic centers at different speeds, and maybe even get pulled a little one way or another by nearby stars. So if it takes decades or hundreds of years to get to the nearest habitable planet, that star system may have already moved away from the predicted location. It's initial position at launch is already years-old information as the light observed is from lightyears away. Then they'd also have to know where the planet is in relation to the star. Imagine if you were trying to enter the Sol system and wasn't sure where exactly Earth was, and came in at the other side of the system from Earth. It would take a lot of fuel to correct the insertion. An interstellar ship would probably either have to be incredibly accurate at its initial trajectory or make many course adjustments, or both.

Manned spaceflight with solar sails is still firmly science fiction.

Perhaps not for long, May 2015 launch date.
http://sail.planetary.org/

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We are able to calculate these positions as to where a cosmic object will be in the future. Think about it. It's quite a trick to reach Mars and the outer planets--these latter with gravitational fly-bys

We are able to calculate these positions as to where a cosmic object will be in the future. Think about it. It's quite a trick to reach Mars and the outer planets--these latter with gravitational fly-bys

We see the objects in our solar system where they were just mere minutes and hours in the past (due to the delay due to time needed for the light/radiation to reach us). That time delay can be computed out without too much error.

Trying that on the scale and time for a galaxy doesn't work so well... All our star positions are distorted by time... And so far for most stars, we have too few observations for good determination of individual galactic orbits.

And all that is distorted again by the expansion of our universe...


... Which is where simulations come to our aid...


Keep searchin'
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

The other problem with navigation is that 95% of the mass of the universe is unknown. So I wonder if their gravitational or anti-gravitational effects might move the stars away from the predictions from models. By the time interstellar travel is attempted, science will probably have taken that into account. But imagine if the trajectory was off by like 0.001 degrees. Assuming the error to act like a right-angle triangle, and the target was 4 light years away, then the error would be like 4 AU in distance, I think. The ship might settle into an irregular orbit around the target star and not have enough fuel to transfer orbit to the planet.

Fuel and propulsion are the key words here. It will be a long time before humans develop a means of propulsion to achieve the necessary velocities and I'm betting FTL velocities will require enough energy(fuel) to power a star for a long time.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

The nearest star is 4 light years away.

Will not be so close, or will be closer in the future...read the article, FIRST!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

The other problem with navigation is that 95% of the mass of the universe is unknown. So I wonder if their gravitational or anti-gravitational effects might move the stars away from the predictions from models. By the time interstellar travel is attempted, science will probably have taken that into account. But imagine if the trajectory was off by like 0.001 degrees. Assuming the error to act like a right-angle triangle, and the target was 4 light years away, then the error would be like 4 AU in distance, I think. The ship might settle into an irregular orbit around the target star and not have enough fuel to transfer orbit to the planet.

With solar sail, the ship can:
1. steer in the solar system
2. parachute itself down to exact position where it wants!

And yes, another type of propulsion will be needed also in depths of Space...


But 0,15LY is well within Oort cloud (1,6LY).
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

The nearest star is 4 light years away.

Will not be so close, or will be closer in the future...read the article, FIRST!
;)

This too was from the article "But Bailer-Jones says their fast speed as they swing by the sun would make reaching those planets as difficult as traveling to more distant star systems." You must read the ENTIRE article and not pick and choose the parts that support your own pet theory.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

With solar sail, the ship can:
1. steer in the solar system
2. parachute itself down to exact position where it wants!

No it couldn't! It's all science fiction, which seemingly you want to believe.

Not for long, May 2015 launch date.
http://sail.planetary.org/

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I think Japan has already successfully implemented a solar sail in the probe IKAROS in 2010. Not sure if this is a typo but articles and Wikipedia say the sail was a square with a 20 meter diagonal. So doesn't that mean 200 square meters? Radius of 10, 10x10 =100, 2x100= 200 square meters? The Planetary Society's sail is 32 m square. Not familiar with the specs so not sure if either probe is testing a unique technology for sails.

The nearest star is 4 light years away.

Will not be so close, or will be closer in the future...read the article, FIRST!
;)

This too was from the article "But Bailer-Jones says their fast speed as they swing by the sun would make reaching those planets as difficult as traveling to more distant star systems." You must read the ENTIRE article and not pick and choose the parts that support your own pet theory.

Have to see the data first...but probably there is a way! Nothing is IMPOSSIBLE...you just have to work a little harder!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU