Beam me to the stars: Scientists propose wild new interstellar travel tech

[Admin]

"Chemical rockets that we use today, even with the extra speed boost from flying by planets, or from swinging by the sun for a boost, just don't have the ability to scale to useful interstellar speeds."

Beam me to the stars: Scientists propose wild new interstellar travel tech : Read more

 

[Catastrophe]

A problem with star travel, is that, unless you are just going to whiz by at interstellar speeds (bit of a wasted journey?) you must carry enough fuel (even if you get there "free") to slow down (and get into orbit around your destination) before arrival.

Cat

 

[motie]

Why do they need propellant or reaction mass? The electron beam collides with the back of the spacecraft, and transfers its momentum to the spacecraft. 100% efficiency. What is wrong with this? I agree that you need a way to slow down. I don't know how to do that.

There is a big problem. How do you aim the beam so that it hits the spacecraft which is very far away? It's a tightly focussed beam. The tiniest angular deflection means that it misses the spacecraft completely.

Another problem: the electron beam is being absorbed by the spacecraft, right? If so, the spacecraft is building a huge negative potential. This will repel the electron beam. That may be OK though, since momentum is still being transferred from the beam to the spacecraft (I think). Or you could design it so the beam strikes an insulating surface and bounces off. It would still transfer momentum.

 

[JPL_ACE]

Motie is right as far as it goes but he missed my main point. That charge build up is a requirement for a ground return. The electrostatic force is far stronger than gravity or kinetic energy and would soon stop the beam from sending an ever increasing neg charge. The other commenters bring up good points too.

 

[Atlan0001]

Interstellar travel is going to require constant power to accelerate contraction of the relative local universe. The same power requirement for deceleration to accelerate expansion of the relative local universe. Accelerating contractions and expansions of the relative local universe . . . the space and, thus, the time.

 

[Dave]

A probe that is a mothership would not need to slow down. It can continue its acceleration and loop. Another craft exiting the main ship can deliver another probe performing its own agenda. The Alpha Centauri star system is intriguing as it has a much larger energy source than our own star system. The triple star system has many more possibilities as an interstellar energy source.

 

[ChrisA]

Let's assume this works. What happens if there is a tiny spec of dust ahead of the spacecraft's path? The dust would hit the spacecraft at 10% of the speed of light. How much armor plate do you need?

THen there is the problem of how to decelerate

 

[Atlan0001]

Let's assume this works. What happens if there is a tiny spec of dust ahead of the spacecraft's path? The dust would hit the spacecraft at 10% of the speed of light. How much armor plate do you need?

THen there is the problem of how to decelerate

Easy. Turn off acceleration in direction and turn end for end in place and resume accelerating . . . thus decelerating.

 

[Catastrophe]

A probe that is a mothership would not need to slow down. It can continue its acceleration and loop. Another craft exiting the main ship can deliver another probe performing its own agenda. The Alpha Centauri star system is intriguing as it has a much larger energy source than our own star system. The triple star system has many more possibilities as an interstellar energy source.

Another ship would still require its own energy to decelerate.

Newton's laws of motion​

Wikipedia
https://en.wikipedia.org › Newton's_laws_of_motion


A body remains at rest, or in motion at a constant speed in a straight line, except insofar as it is acted upon by a force.

Cat

 

[ChrisA]

Easy. Turn off acceleration in direction and turn end for end in place and resume accelerating . . . thus decelerating.

But we are talking about a spacecraft that is powered by an electron beam. We have to assume there is some like oc beam receiver that always has to face Earth. If you flip the spacecraft around, then it is unpowered.

The bigger problem is that the people who invented this idea of using an electron beam did not propose any way of receiving the beam and turning it into thrust. Maybe this is impossible?

If they are using only the beam's momentum then there is literally no way to slow down, the spacecraft would pass by the star at high speed. But maybe that is good enough if the main purpose of the mission is "bragging rights" just to say you sent something to "The Stars". It is hard to imagine how a useful instrument and radio transmitter could fit inside such a tiny spacecraft

 

[ChrisA]

A probe that is a mothership would not need to slow down. It can continue its acceleration and loop. Another craft exiting the main ship can deliver another probe performing its own agenda. The Alpha Centauri star system is intriguing as it has a much larger energy source than our own star system. The triple star system has many more possibilities as an interstellar energy source.

This idea only works if somehow the space probe can store the energy from the beam and then convert the stored energy to thrust.

The words "storing the energy from the beam" are just hand waving unless someone can show that it is at least possible. They did not even suggest it in the article.

 

[dark_penguin]

A problem with star travel, is that, unless you are just going to whiz by at interstellar speeds (bit of a wasted journey?) you must carry enough fuel (even if you get there "free") to slow down (and get into orbit around your destination) before arrival.

Cat

I agree that the issue of how to slow down at the destination has been under-discussed. The only good solution I have ever seen for this comes from Robert L. Forward, which he employs in his 'Dragonfly' series of novels, and uses a laser-propelled light sail. The key innovation is that the outer ring of the sail detaches for the deceleration phase, reflecting the beam back at the craft to slow it down.

More Info Here

 

[Catastrophe]

Reflecting light back?

Effect is to propel vessel forward?

Solution from fiction?

Cat

 

[Atlan0001]

How much energy is there in gamma rays, x-rays, any cosmic rays? How much energy is there in interstellar cosmic energies, the so-called interstellar and intergalactic dark energy vacuum? Providing we learn how to access it -- to collect it directly from space if we can -- and use its unlimitedness for continuous power for continuous acceleration.

 

[Unclear Engineer]

The only way I can think of to effectively turn the probe around would be to do a gravitational "collision" with a planet or star in the target system. But, that would at best be a parabolic orbit, so it would not come directly back to Earth. Perhaps it could still be "steered" with the electron beam on its return, so that it is deflected enough sideways to get on a trajectory back to Earth.

There is so much hand waving in this concept's description that it is hard to think of how the probe is actually propelled, so thinking about how to deflect it's return trajectory is another step beyond.

Still, I think it is worth the effort to think about it in as realistic manner currently possible.

 

[Classical Motion]

Let’s say we get accelerated to velocity from that beam and we are half way to our destination star.

So now we want power to decelerate. But it will take several years for the beam to get there.

Pretending a beam could.

Or we are halfway there, and a collision is eminent, and the travel time of the beam is longer then the collision time.

This is a cornball idea.

 

[Unclear Engineer]

My first question about practical reality is:

What happens to a piece of metal when it gets hit by an electron going at 90% of the speed of light? Assume aluminum, iron or titanium.

 

[Classical Motion]

I don’t know how to compare 90% c …. to the velocity of electrons in a vacuum tube. But if you turn the voltage up, the plate, or target will emit x-rays. That would be a loss in energy. A High energy loss.

 

[Atlan0001]

Or, when the ship that has been under continuous power is inerted it will match physics with the locality. The wormhole will disappear (the duality will disappear) . . . the local-relative universe, including the ship, will renormalize, just like it does in science-fiction. If Jules Verne could forecast modern physics to a certain degree, so can those who can see and predict the potential future in 21st century realizations of physics.

-------------------------

The scientist Lord Kelvin in the 1890s predicted that no heavier than air craft could ever fly. It didn't take long to disprove that.

John von Neumann predicted in the 1940s that computers would become so titanic they would occupy entire city blocks and no could afford the computer but the richest countries and corporations. Our cell phones and some watches alone have undone that great scientist's prophecy.

The prediction today is that our future power technologies in our spaceships will never contract the relative local universe around the spaceship to a form of Lilliputian "fly over country" ("spooky action at a distance"). Also, will never protect us from the environment of space.

To date, history has proved the naysayers wrong again and again, and again, regarding genius, technologies and regarding adapting environments to suit!

 

[George²]

If the ship is light enough and highly resistant to radiation, it can be directed close to the star and use energy to slow down or correct the trajectory not only of its gravity, but also the radiation emitted by the star, as well as its electromagnetic fields.