Current solar sail materials will let us pass within 30 solar radii of the sun but withstanding the heat and getting closer enables far faster speeds. The right metal solar sail would let us get within 5-10 solar radii. A dielectric ceramic solar sail would let us get within 3 solar radii. We would then need to work on multiple layers to get from about 10% reflectivity to 90% or more reflection. Making a light and thin solar sail out of the right layering of materials will let us send objects at speeds of 25 AU (distance from the Earth to the sun) per year. This would mean 20-year missions to the 500 AU start of the gravitational lens. At the gravitational lens areas, we could look on the other side of the sun with 10 billion times better magnification to explore the surface of exoplanets.
Davoyan’s group is working on unpowered solar sail material, laser pushed optimized solar sail material and ultrathin (10 nanometers thick) solar cells. The ultrathin solar cells would potentially enable greater than 10 kilowatt per kilogram power generation. Ultra-high power with ultra low weight enables ultra high speeds and other fantastic space vehicles.
SOURCES- UCLA, NASA
Written By Brian Wang, Nextbigfuture.com
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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My understanding is that it depends on how you define "difficult".
In pure technical terms, it's deltaV. And that doesn't really matter if it's at the distance of the moon or Saturn. Though control is more difficult at long distance.
But in project management terms, the difficulty in raising funds, keeping the team together, getting people to fund you and having the organisation function effectively over the scope of the project… time is a huge factor. And having your target 3 days away is MUCH easier to do a plan for than 7 years there and another 7 back.
I c. On a related topic, slow solar system light sails, what about putting lightsail on a *large* NEO and using it to push the 'roid so it passes close to the Earth, but not stopping. Perhaps a harmonic orbit that does this repeatedly. Clearly easier than bringing into capture cislunar. So, the question is: does the near pass make it much easier to grab a piece as it goes by, or is the main factor the v? It would be nice to grab small amounts while waiting for the big *strike*, as in gold.
Speculation time: The larger and brighter the star, the faster you can leave the solar system even if you are limited to the the same maximum light intensity at your starting point.
AFAICT, the total work done on the solar sail is the integral from peak intensity (set by materials limits) to infinity of X/(d/d0)^2 as the radiation pressure dies away with distance squared.
With starting distance d0 proportional to the square root of star brightness.
The work = final kinetic energy = 1/2 M v^2. So final velocity is proportional to star brightness. Until you reach near C of course.
And if little old Sol with get you to 3% of C, then the same tech can get you very close to C with some of the monster sized stars out there. Let alone some of the really bright stuff.
Meaning that Aliens with access to really bright stars could launch C level probes with what looks like late or even mid 21st century tech.
So we really could have encounters with visitors from other stars with tech levels that aren't god-like.
What about those idiots who sent multiple Mars rovers to the same, single planet?
You do realize that capacitors have electrodes, and a huge advantage, stated in the story, of the glass is that it does not conduct electricity, so is resistant to solar wind?
You do realize that a capacitor has electrodes?
More so than you think.
It doesn't extend to infinity. It dies away at about 2000 AU.
If it DID extend to infinity, we could just use the gravitational lens of Proxima Centuri with our telescopes here on earth (or earth orbit) and not worry about getting to 500 AU.
And then why worry about Proxima Centuri when we could use UY Scuti, or a galactic central black hole.
Which the story does not.
Actually ICE is still referring to capacitors… and inductors.
I prefer EV
ICE
Single LINE you mean, not single point. The gravitational focus is a line extending to infinity, not a point
You are a mind reader!
The casimir effect makes me think of Led Zepplin.
The nearer you can get to the sun, the faster you can leave the solar system. This is relatively low cost research than can have great payback.
Not at all. The solar gravitational lens *starts* at 500 AU but extends more-or-less infinitely behind it. The only thing is that the ring of light the star's gravity focus the light behind it as increases in radius. The lens is said to start at 500 AU because at that distance it is reasonably larger than the star's own radius such that you can observe it and not have the corona (or the lower layers of the Sun) wash it out.
Exactly. You not only need to get there, but to slow down upon arrival. A solar sail probe moving at relativistic speed won't be able to slow down unless there's someone on the other end shooting a deceleration laser in the other direction.
As many as you want. The size is up to you. How much water you drink does not change the nature of water.
And how many Farads is that again?
Actually it's not retarded at all.
Today most space probes are sent to a single asteroid.
Using solar sails and mass production you can send many probes each will be used for a single planet.
Even if you build a huge space telescope with 1000m lens you wouldn't get enough resolution to study such a planet.
Launching a telescope to 500 AU in 20 years to look at one single star is retarded. These oh-so-smart engineers need to think less "possible" and more "practical".
The mirror comes from moving electron, dielectric mirror does not store the moved electron as charge shift, but it moves back to emit the *reflected* photon, actually a new one. The electron is stuck within the glass, so cannot move very far, and so either absorbs the photon or misses it. There is no absorption that then gets lost and becomes heat, as on metal.
How many farads is that?
Dielectric mirrors are very interesting.
As Jim explains, the image is constructed from info that is not completely focused. So parts of it can be collected by moving observatories. Actually, the whole set of detectors together is the observatory. That plus the Sun make a telescope. But otherwise, you have the problem correctly stated, it is not pointable the way other detectors are, even interferometry can see different directions from fixed locations.
Sounds like they're making a capacitor instead of a solar sail.
My understanding is that gravitational lensing doesn't focus on a point, but that you get useful lensing on a line extending away from the sun opposite to the object to be observed. You need to be more than about 550 AU for it to work & it works OK at greater distances, so braking to a halt relative to the sun isn't needed.
https://en.wikipedia.org/wiki/Gravitational_lens#Solar_gravitational_lens
The energy required to stop at 600AU is huge. Also the space craft will need to carry all that fuel during acceleration.
Then it will need to accelerate again and travel 10's of AU's to relocate for a different solar system.
It's much more efficient to dedicate one gravitational telescope sensor per one target solar system.
Thus sensors can be made in large quantities at low cost per system.
And what is the point of doing a high speed fly-by of a single point in space where you have gravitational lensing in one direction?
A gravitational lensing observatory needs to be radially stationary relative Sun so it will have to brake. It will also need to adjust the orbital plane to be able to observe different targets so advanced propulsion is needed. In practice, we will need thousands of observatories to be able to see all stuff around us.