To Mars in three days?
In late February, many media outlets published the news that NASA had invented a way to fly to Mars and other planets at near-light speeds. It was about the work of the professor of the Faculty of Physics of the University of California at Santa Barbara Philip Lubin (Philip Lubin). The meaning of the messages was reduced to the fact that NASA, in the person of the aforementioned professor, is going to launch probes to the planets of the Solar System and beyond by using a laser beam illuminated from the Earth. Promised delivery of a 100-kilogram apparatus to Mars in three days and other fantastic possibilities. Apparently, due to the obvious yellowness of the headlines, no one ventured to republish such news here and on similar resources. I wondered what was behind the loud headlines and what I found out.
In fact, the news was not so fresh, some media published it in the summer of 2015. Now the impetus for this topic was given by the publication of the NASA 360 podcast (and the subsequent Space.com site) a video clip, which popularly explains the proposed technology.
This video does not contain any scientific and technical details, and consists almost entirely of various fragments of Shuttle launches and other space videos. The technology itself says only that it is supposed to use photon propulsion to disperse the spacecraft, i.e. photon pulse energy. In fact, the idea of ​​a photon engine is not at all new, but researchers are proposing a completely new approach - the transfer of an impulse is accomplished by the “illumination” of a moving object by a laser beam from the Earth or an orbital platform. Thus, it is proposed to get rid of the necessary fuel reserves on board the object itself, and it is argued that such an approach would allow near-light speeds to be reached.
')
Philip Lubin is the project manager for DEEP-IN (Directed Energy Propulsion for Interstellar Exploration), funded by NASA. In April 2015, he published a scientific paper called “Roadmap of Interstellar Flights” (A Roadmap to Interstellar Flight) , in which he proposed a technology for transmitting photons to a spacecraft by an array of lasers installed on Earth, and also gave calculations confirming the theoretical possibility this technology. In August 2015, NASA allocated $ 100,000 for further research of this group.
Further, I will try to briefly outline the main points outlined in this work.
The introduction says that over the past 60 years of the space age, humanity has achieved great success in the development of space technology, with the exception of only the speed characteristics of spacecraft. For example, Voyager-1 managed to leave the Solar system only after 37 years of flight, having a speed of 17 km / s, i.e. 0.006% of light. This is clearly not enough for flight, even to the nearest stars.
For remote transmission of energy, it is proposed to use a photon driver (photon driver) - an array of lasers, kilowatt class, with exactly the same phases, working as a single light source. This approach will allow to abandon the development of a single super-power laser, as well as giant optical systems (since each laser in the array has its own optical system). A similar array is described in other papers by a research group called DE-STAR (Directed Energy System for Targeting of Asteroids and ExploRation). It is proposed to supply the array with the energy of the corresponding set of solar cells.
DE-STAR arrays are proposed to be built in various sizes, in logarithmic progression from their number. Those. DE-STAR 1 will have a side of 10 meters, DE-STAR 2 - 100 meters and so on. For example, the characteristics of the array of the maximum size of DE-STAR-4 and a power of 50-70 Gigawatts, which, being in a low earth orbit, will allow to disperse the femto satellite (made in the form of a single crystal, weighing about 1 gram) with a sail with a side of 1 meter from a thin film, up to about 26% of light speed in about 10 minutes. Such a device will reach Mars in 30 minutes, will overtake Voyager 1 in less than 3 days and reach Alpha Centauri in about 15 years. As other examples, it is said that such an array could accelerate an object weighing 100 kg to about 2% of the speed of light, and an object weighing 10,000 kg to 1,000 km / s.
Taking into account the fact that it takes very little time for the femto satellite to accelerate, after which the array of lasers is actually unnecessary, it is theoretically possible to launch hundreds of such devices daily and launch about 40,000 of them every year, which will allow you to have one for each square degree of the sky ( it is assumed that the total mass of all femto satellites will be about 80 kg).
Further, the work presents calculations of the necessary energy for acceleration of objects to near-light speeds, as well as calculations of the required sail sizes for collecting the transmitted energy. It is also proposed to use part of the received energy for the own needs of the spacecraft, which, on the one hand, will reduce the efficiency of energy transfer, and, on the other hand, will significantly simplify the device itself. In addition, the design and calculations required for the construction of an array of lasers.
A serious problem can be the braking of the vehicle arrived at the scene. To this end, it is proposed to use the energy of the photons emitted by the star, the stellar wind, as well as the magnetic coupling with the plasma of the star system. It is indicated that it will take many years of experimentation to learn how to use these capabilities, but flying missions are already available.
Another practical aspect of the use of laser arrays can be long-distance communication with the apparatus. For example, the calculation is again given for the DE-STAR-4 array with a wavelength of 1.06 ÎĽm and a power of 50 GW. It is said that at a distance of 1 light year the diameter of the light spot will be 2 * 10 6 meters (2 000 km), which for a probe weighing 100 kg and a receiving antenna with a diameter of 30 meters will allow data to be received at a speed of 2 * 10 18 bps (assuming that the device needs 40 photons to encode the 1st bit). At the same time, having a laser transmitter with a power of 10 W on board will be able to transmit information in the same way at a speed of 1 * 10 9 bit / s (ie, 1 Gbit / s). Similarly, it is calculated that being near Proxima Centauri this data transfer system will provide a speed of about 70 Mbps. Those. humanity will have the opportunity to watch live video broadcast from a nearby star system.
As an additional opportunity to use a laser array, military and protective targets are offered, for example, protection from asteroids, as well as signaling to extraterrestrial civilizations.
At the end of the article, some calculations are given for future spacecraft sent using a laser array with a capacity of 70 GW:
Thus, the article states that the proposed technology, despite its fantastic nature, is quite possible in the foreseeable future and is clearly more real than wormholes, teleportation, and antimatter engines. Of course, it will take some time until technology develops enough to create spacecraft weighing a few grams and the laser arrays necessary for acceleration. Agree with this or not - everyone can decide on their own. For me, it is important that NASA also saw sound grain in this work and is funding further development. The next steps can be first ground testing of the technology of impulse transfer, and then testing in orbit of the earth laser arrays of different power.
As expected, the proposed theory has opponents. In addition to the technical impossibility of launching such a spacecraft at the present time, other theoretical and practical difficulties are also called. For example, they say that the laser sail is very hot while the laser machine is operating or that if the sail (and it should reflect 99.99% of the received energy) will reflect 70 Gigawatts of energy back to the laser array, then the latter will not be well. Newton's 3rd Law is also mentioned, according to which a huge counter force will act on a space platform on which an array of lasers will be installed (although the platform itself, according to the calculations of the same critics, will have an exorbitant mass of about 300,000 tons).
In any case, time will tell who was right and who was not.
I apologize for using the term "femto satellite" for the devices mentioned in the article, since the term "wafer scale spacecraft" is used in the original, which is not translated by any term known to me.
List of links:
In fact, the news was not so fresh, some media published it in the summer of 2015. Now the impetus for this topic was given by the publication of the NASA 360 podcast (and the subsequent Space.com site) a video clip, which popularly explains the proposed technology.
This video does not contain any scientific and technical details, and consists almost entirely of various fragments of Shuttle launches and other space videos. The technology itself says only that it is supposed to use photon propulsion to disperse the spacecraft, i.e. photon pulse energy. In fact, the idea of ​​a photon engine is not at all new, but researchers are proposing a completely new approach - the transfer of an impulse is accomplished by the “illumination” of a moving object by a laser beam from the Earth or an orbital platform. Thus, it is proposed to get rid of the necessary fuel reserves on board the object itself, and it is argued that such an approach would allow near-light speeds to be reached.
')
Philip Lubin is the project manager for DEEP-IN (Directed Energy Propulsion for Interstellar Exploration), funded by NASA. In April 2015, he published a scientific paper called “Roadmap of Interstellar Flights” (A Roadmap to Interstellar Flight) , in which he proposed a technology for transmitting photons to a spacecraft by an array of lasers installed on Earth, and also gave calculations confirming the theoretical possibility this technology. In August 2015, NASA allocated $ 100,000 for further research of this group.
Further, I will try to briefly outline the main points outlined in this work.
The introduction says that over the past 60 years of the space age, humanity has achieved great success in the development of space technology, with the exception of only the speed characteristics of spacecraft. For example, Voyager-1 managed to leave the Solar system only after 37 years of flight, having a speed of 17 km / s, i.e. 0.006% of light. This is clearly not enough for flight, even to the nearest stars.
For remote transmission of energy, it is proposed to use a photon driver (photon driver) - an array of lasers, kilowatt class, with exactly the same phases, working as a single light source. This approach will allow to abandon the development of a single super-power laser, as well as giant optical systems (since each laser in the array has its own optical system). A similar array is described in other papers by a research group called DE-STAR (Directed Energy System for Targeting of Asteroids and ExploRation). It is proposed to supply the array with the energy of the corresponding set of solar cells.
DE-STAR arrays are proposed to be built in various sizes, in logarithmic progression from their number. Those. DE-STAR 1 will have a side of 10 meters, DE-STAR 2 - 100 meters and so on. For example, the characteristics of the array of the maximum size of DE-STAR-4 and a power of 50-70 Gigawatts, which, being in a low earth orbit, will allow to disperse the femto satellite (made in the form of a single crystal, weighing about 1 gram) with a sail with a side of 1 meter from a thin film, up to about 26% of light speed in about 10 minutes. Such a device will reach Mars in 30 minutes, will overtake Voyager 1 in less than 3 days and reach Alpha Centauri in about 15 years. As other examples, it is said that such an array could accelerate an object weighing 100 kg to about 2% of the speed of light, and an object weighing 10,000 kg to 1,000 km / s.
Taking into account the fact that it takes very little time for the femto satellite to accelerate, after which the array of lasers is actually unnecessary, it is theoretically possible to launch hundreds of such devices daily and launch about 40,000 of them every year, which will allow you to have one for each square degree of the sky ( it is assumed that the total mass of all femto satellites will be about 80 kg).
Further, the work presents calculations of the necessary energy for acceleration of objects to near-light speeds, as well as calculations of the required sail sizes for collecting the transmitted energy. It is also proposed to use part of the received energy for the own needs of the spacecraft, which, on the one hand, will reduce the efficiency of energy transfer, and, on the other hand, will significantly simplify the device itself. In addition, the design and calculations required for the construction of an array of lasers.
A serious problem can be the braking of the vehicle arrived at the scene. To this end, it is proposed to use the energy of the photons emitted by the star, the stellar wind, as well as the magnetic coupling with the plasma of the star system. It is indicated that it will take many years of experimentation to learn how to use these capabilities, but flying missions are already available.
Another practical aspect of the use of laser arrays can be long-distance communication with the apparatus. For example, the calculation is again given for the DE-STAR-4 array with a wavelength of 1.06 ÎĽm and a power of 50 GW. It is said that at a distance of 1 light year the diameter of the light spot will be 2 * 10 6 meters (2 000 km), which for a probe weighing 100 kg and a receiving antenna with a diameter of 30 meters will allow data to be received at a speed of 2 * 10 18 bps (assuming that the device needs 40 photons to encode the 1st bit). At the same time, having a laser transmitter with a power of 10 W on board will be able to transmit information in the same way at a speed of 1 * 10 9 bit / s (ie, 1 Gbit / s). Similarly, it is calculated that being near Proxima Centauri this data transfer system will provide a speed of about 70 Mbps. Those. humanity will have the opportunity to watch live video broadcast from a nearby star system.
As an additional opportunity to use a laser array, military and protective targets are offered, for example, protection from asteroids, as well as signaling to extraterrestrial civilizations.
At the end of the article, some calculations are given for future spacecraft sent using a laser array with a capacity of 70 GW:
| one | 2 | 3 | four | five | 6 | 7 | eight | 9 |
|---|---|---|---|---|---|---|---|---|
| 1 g | 0.85 m | 186 seconds | 4.01 * 10 9 m | 4.31 * 10 7 m / s | 0.14 | 6.10 * 10 7 m / s | 0.20 | 2.37 * 10 4 g |
| 10 g | 2.7 m | 1050 s | 1.27 * 10 10 m | 2.43 * 10 7 m / s | 0.081 | 3.43 * 10 7 m / s | 0.11 | 2.37 * 10 3 g |
| 100 g | 8.5 m | 5880 s | 4.01 * 10 10 m | 1.36 * 10 7 m / s | 0.046 | 1.93 * 10 7 m / s | 0.064 | 237 g |
| 1 kg | 27 m | 3.32 * 10 4 s | 1.27 * 10 11 m | 7.67 * 10 6 m / s | 0.026 | 1.08 * 10 7 m / s | 0.036 | 23.7 g |
| 10 kg | 85 m | 1.86 * 10 5 s | 4.01 * 10 11 m | 4.31 * 10 6 m / s | 0.014 | 6.10 * 10 6 m / s | 0.020 | 2.37 g |
| 100 kg | 270 m | 1.06 * 10 6 s | 1.27 * 10 12 m | 2.43 * 10 6 m / s | 0.0081 | 3.46 * 10 6 m / s | 0.011 | 0.237 g |
| 1000 kg | 850 m | 5.88 * 10 6 s | 4.01 * 10 12 m | 1.36 * 10 6 m / s | 0.0046 | 1.93 * 10 6 m / s | 0.0064 | 0.0237 g |
| 10,000 kg | 2.7 km | 3.32 * 10 7 s | 1.27 * 10 13 m | 7.67 * 10 5 m / s | 0.0026 | 1.08 * 10 6 m / s | 0.0036 | 2.37 * 10 -3 g |
| 100,000 kg | 8.5 km | 1.86 * 10 8 s | 4.01 * 10 13 m | 4.31 * 10 5 m / s | 0.0014 | 6.10 * 10 5 m / s | 0.0020 | 2.37 * 10 -4 g |
- Mass of the device
- Sail size
- The time it takes for the unit to be removed to a distance at which a spot of laser beam completely illuminates the sail.
- The distance from the light source at which the spot of the laser beam completely illuminates the sail
- Speed ​​at that point
- Proportion of the speed of light
- Maximum speed with constant light
- The proportion of the speed of light under constant illumination
- Acceleration at the moment when the spot of the laser beam completely illuminates the sail
Thus, the article states that the proposed technology, despite its fantastic nature, is quite possible in the foreseeable future and is clearly more real than wormholes, teleportation, and antimatter engines. Of course, it will take some time until technology develops enough to create spacecraft weighing a few grams and the laser arrays necessary for acceleration. Agree with this or not - everyone can decide on their own. For me, it is important that NASA also saw sound grain in this work and is funding further development. The next steps can be first ground testing of the technology of impulse transfer, and then testing in orbit of the earth laser arrays of different power.
As expected, the proposed theory has opponents. In addition to the technical impossibility of launching such a spacecraft at the present time, other theoretical and practical difficulties are also called. For example, they say that the laser sail is very hot while the laser machine is operating or that if the sail (and it should reflect 99.99% of the received energy) will reflect 70 Gigawatts of energy back to the laser array, then the latter will not be well. Newton's 3rd Law is also mentioned, according to which a huge counter force will act on a space platform on which an array of lasers will be installed (although the platform itself, according to the calculations of the same critics, will have an exorbitant mass of about 300,000 tons).
In any case, time will tell who was right and who was not.
I apologize for using the term "femto satellite" for the devices mentioned in the article, since the term "wafer scale spacecraft" is used in the original, which is not translated by any term known to me.
List of links:
Source: https://habr.com/ru/post/391537/
All Articles