Hawking-Milner StarShot possible
Common sense suggests that for a flight to another star system, either a propulsion system of a new type is necessary, patience stretched over several generations, or overcoming the laws of physics. But if you refuse to send a person or a traditional spacecraft – can you come up with a better technology, innovative and simple? The year before last, a team of scientists wrote a paper on how a laser array can be combined with the concept of a solar sail to create a spacecraft with a laser sail. In theory, the existing technologies, coupled with extremely light spacecraft (“cosmicchips”), can allow us to reach the nearest stars during one human life.
The advantages of such a project are amazing:
• Most of the energy of such a ship does not come from single-use rocket fuel, but from lasers capable of recharging.
• The masses of cosmic chips are extremely small, so they can be accelerated to very high velocities close to the speed of light.
• With the current success of miniaturization of electronics and the creation of very light and durable materials, we can indeed create useful devices and send them over many light years.
The idea is not new, but the development of new technologies – already available, and those that will be available in 20-30 years – makes this possibility realistic.
Moreover, since billionaire Yuri Milner donates $ 100 million to the project under the initiative of the Breakthrough Initiative, it seems that humanity will still reach the stars. This concept was approved by many serious scientists, as the technology develops very quickly. Nanomaterials are getting better, and we can expect that we will be able to build a sail weighing 1 gram and an area of 1 m², capable of reflecting a laser beam. One of the recent advances in laser technology has been the ability to collect lasers into a large array that can focus on one target. Subsequent improvements in laser power and collimation mean that the laser can disperse the target to an acceleration radically exceeding the capabilities of lasers in the 1990s.
Having built a huge array of lasers in space, It on these one-gram reflecting sails and constantly shooting at them, we can disperse these cosmic chips to speeds of more than 60 000 km / s, that is about 20% of the speed of light. With such speed they will reach the nearest star system in 22 years, and we will be able to fly to 100 nearest systems known to us within 100 years. The size of the laser array will require a giant: about 100 km ², which corresponds to about 2/3 of the area of the state of Liechtenstein. But with him the problem is only in value, not in technological limitations.
It looks too good to be true. In fact, when describing the project, several of its shortcomings were not mentioned:
• The array of lasers are going to be built on the surface of the Earth, and not in space. It is easier to create and maintain, not to mention the fact that it will cost 50 times less, but the atmosphere dissipates light, and therefore only a small fraction of it will reach the cosmo-chips. Possible Less light – less acceleration, and less travel speed makes the project less attractive.
• Any type of flow into a structure such as a sail will cause the angular momentum to appear and cause it to rotate. It is not clear how it will be possible to keep such a sail from rapid rotation and escape from control without the use of a heavy stabilizing mechanism on board.
• Even if you achieve the goal, you can not slow down or transfer information to Earth. So far, the energy available to such a small cosmicope will not be enough to transmit anything to Earth that we can detect.
• And finally, money: $ 100 million seems like a lot of money, but it’s less than 1% of the cost of such a project, not to mention the development of technology that does not yet exist. possible
There is hope to solve some of these problems, but for now That from a scientific point of view, they are not completely fully worked out. Will there be improvements in laser collimation technology? Will we build such a huge (or powerful) array that it can transmit a sufficiently large amount of energy to the laser sail? Will we build a sail thinner and larger in area so that it can get a bigger boost? Will the sail, even with a reflective capacity of 99.9995%, withstand a gigawatt laser, or will it destroy 0.0005% of the absorbed energy?
What about the rotation problem; Do we invent and develop nano-gyroscopes capable of stabilizing the sail against rotation? If not, can we direct it towards another stellar system, or will it fly where it will be, while a mistake of even 0.1% will lead to a miss by the goal of billions of kilometers? What about the transmission problem; Will we lay a tiny amount of plutonium-238 in the generator of each ship? Do we hope for a new technology that has not been developed yet? If we take into possible account that most of the instruments, even from Voyager ships, at a trifling distance of 0.002 light years, can not communicate with the Earth, how can we hope that a single-chip chip will be able to send us a message from distances of 1000 times greater?
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The logarithmic scale of distances demonstrating Voyager spacecraft, our solar system and the closest star for comparison
The last problem can be the most difficult. As the planetologist Bruce Betts says:
If you could fly into the forest and see how the tree falls, but could not tell anyone about it, would it make any difference?
This is perhaps the most difficult poosible of the project: are we spending tens of billions of dollars just to deliver one-gram artifacts from the Earth into deep space, never to hear from them again?
I’m not saying that this is not done Just let’s be honest about the project’s problems. If we do this, we must do it right and put as much effort into this attempt as possible. This is an amazing opportunity to be explored further, but $ 100 million and our latest technologies do not even begin to bring us closer to the goal.
