Interplanetary Internet
Space expansion continues. Until 2030, more than half a dozen countries plan to carry out manned missions to the Moon. Preparations are under way for the landing of a man on Mars. By the end of this century, a permanent research station will be built on the moon, and perhaps a residential colony. In the next century, humanity may well settle on the Moon and Mars. But what about the fact that so firmly binds us all - with the Internet? Is it possible to combine several planets into a single global network? Under the cut - a symbiosis of real achievements and the author’s fantasy with elements of astronautics, astrophysics and network technologies.
The idea of ​​this post arose from a friendly discussion on the topic: is it possible to exhaust IPv6 addresses if they start to be used on everything from computers to refrigerators and washing machines? And when will we start settling the moon and mars? And then there are more questions. The average distance from the Earth to the Moon is about 384 thousand km. The signal travels this distance in about 1.3 seconds. Add some delays on the routing equipment and get an approximate ping in a couple of seconds (maybe up to 3 between opposite points of the planets). Running into a counter will not work, but sourcing and even speaking in a voice can come out, albeit with very noticeable brakes.
')
Mars is harder. The distance between the planets varies from 54.6 to 401 million km, which corresponds to the signal transit time from about 3 to more than 22 minutes. And in fact, the upper limit will be even higher. The Sun will be at the most distant points of the orbits between the planets, and it is unlikely that it will “shout” its background with its transmitters. It is necessary to launch the relay at a certain distance from the Sun, which still significantly increases the signal transit time.
The average distance between Earth and Mars is 225 million km (12.5 minutes). Let's try to imagine the classic chain, which occurs when you load the usual modern page, but at a distance of 225 million km. After we enter the address, a request is sent to the DNS service (from Mars to Earth, of course), the IP address is returned. Hooray! After 25 minutes, our Martian computer knows where to send the HTTP request. After another 25 minutes, the browser will receive an html document with links to all css, js files, pictures, etc. and send requests to receive them. The resulting style sheets and scripts can refer to some other images, and God forbid, the site creators guessed to put them in some separate subdomain or use hotlinking (here not only webmasters, but users would also want to burn hotlinkers in hell ). Total, the total load time of one page on the existing scheme today can easily reach one and a half to two hours. And we are considering this ideal variant, in which not a single packet was lost or damaged, which is unlikely at such distances. Really, going to Mars, will you have to forget about the video with cats?
It should be noted that the laying of a network between the planets and spacecraft is not such an invention of science fiction. The development of a protocol that would allow the exchange of data in space began in 1998. And one of the ideological inspirers of the new protocol was Vinton Cerf, who 25 years before had been directly involved in the development of modern Internet protocols. The new group of protocols was named Bundle (English package, bundle, bundle) and became an integral part of the direction of Delay-tolerant networking (networks tolerant to delays). Details of his work have already been dismantled in an article on Habré . I remind you of the key problems that have made the use of modern protocols impossible.
The modern TCP / IP protocol, on which the entire Internet rests, suggests that a data packet is relatively small in size, can be delivered very quickly and does not need long-term storage. If the next route node is not available, the corresponding response is returned, and the packet is removed. In space, where everything is constantly moving, rises and sets, turns and turns, data sessions are often tied to the windows of visibility. The old model of remote space communications provided for direct data transmission from the spacecraft to Earth during the window of view of the transmitting and receiving antennas. The new model assumes that the spacecraft will contain a relay function capable of storing large data packets and transmit them further as soon as the communication window opens. This principle was laid in the new protocol.
The remoteness of the nodes also causes problems with network management. The SNMP management protocol assumes that network nodes respond to the request fairly quickly. The normal response time does not exceed several hundred milliseconds. If a node does not respond for a few seconds, most likely it is not available, and we have a reason to send the packet by another route, if it exists. On a cosmic scale, it may take several hours or even days to fully verify that there are problems on a node. I did not come across information about how you plan to solve this problem. If someone knows, please share.
Another problem, as already mentioned, is the DNS system. Banal domain resolution in IP can take a considerable amount of time. Therefore, it was decided to introduce a two-phase search and the so-called delayed resolution. The first phase is the determination of the desired planet / station and the laying of a route to it, the second is a request to the corresponding local base. Apparently, we should expect that over time, IANA will add the suffix .earth to all root zones, or simply launch separate zones .moon, .mars, etc.
Certain improvement requires security, especially from man-in-the-middle attacks . Therefore, it was decided to introduce additional security measures, including encryption, authentication, etc.
Naturally, the first who began to test and put into practice DTN protocols were the space agencies. Thus, different versions of the protocol were introduced to some near and far NASA space programs. A prototype of this protocol was laid in the Mars rovers Spirit and Opportunity , launched back in 2003. By the way, it is worth noting that, as of February 18, 2015, Opportunity is still alive, well, it goes and sends data to Earth.
Another rover, launched much later and using a more modern version of the protocol - Curiosity . This unit, as usual, has the functionality of direct communication with NASA's centers for remote space communications, however most of the data is transmitted through two near-Marc orbiters: the main part is transmitted via the Mars Reconnaissance Orbiter , if necessary, Mars Odyssey is also involved. Thus, two problems are solved at once. First, the device is easier to communicate with the Earth. In the case of a direct connection, Curiosity is available about half a day due to the rotation of Mars. Low-orbiting satellites, in turn, make several full turns per day (for example, the Mars Reconnaissance Orbiter orbital period is less than 2 hours). Thus, if necessary, you can communicate with the landing gear in a reasonable time, transfer control commands and receive data, even when it is on the reverse side of Mars.
In fairness, it is worth mentioning that Spirit and Opportunity kept in touch mostly in the same way, through the same intermediate stations. They were also used by the Phoenix landing gear, which investigated the polar cap of Mars, until the Martian winter took it. Martian winter is dark and full of horrors ...
However, the first serious interplanetary Internet testing was carried out not at all on these missions, but on the EPOXI , which was previously the “mother ship” of the Deep Impact mission. After the separation of the “drummer” in 2005, the device still flew for 2 years in sleep mode, from which it was taken out every six months to test its performance. And in 2007 they decided to repurpose the mission. And one of the new tasks assigned to the device was testing the prototype interplanetary Internet in mid-October - mid-November 2008, during which many images were successfully transferred from the device and back.
Middle Space is also actively involved in testing. The first experiments with the DTN protocol on the International Space Station were carried out by the 18th expedition. And now that year, the experiments are regularly extended. According to the official information on the project page in experiments with DTN, missions took place from 18 to 42 between March 2009 and March 2015. It is likely that the experiments will be extended to further missions.
Technologies created for space, found and quite terrestrial application. As often happens with good developments, the military became interested in technology. In a battlefield environment, it is more convenient to communicate using a protocol that allows for interruptions in connectivity.
However, science and social sphere also did not stand aside. So, some early adaptation of the protocol was used to observe the movement of African zebras. The sensors, mounted on separate zebras, were equipped with a small storage, GPS and transceiver with a range of about 8 km. The territory on which the observations were made was practically devoid of stationary repeaters, so it was decided to transmit the movement log of animals using a network formed from the zebras themselves, which was called ZebraNet .
In the next 10-15 years, several countries are planning the landing of people on the moon. The EU and China are developing their programs in this direction. The United States plans to conduct tests of the Orion in lunar orbit as part of the preparation of a manned mission to Mars. More vague on the dates of the lunar programs are India, Japan, Russia and Iran. There are also plans to create permanent bases on the Moon and colonize Mars without the possibility of returning to Earth as early as this century. And all these people will need a connection.
The International Consultative Committee on Space Data Communication Systems ( CCSDS ) already now offers all space agencies in the world to install equipment operating with the new protocol on their new automated and manned spacecraft. This will not only make communication with devices more convenient, but also gradually increase the number of routing nodes as the devices complete their main tasks in the mission.
Leading scientists of the world have shown all their ingenuity to ensure the most uninterrupted connection between the terranet and the selenite (from the ancient Greek goddess of the Moon - Selena). The Earth is surrounded by a network of entry points to the global interplanetary network, each of which corresponds to one of the geostationary hop - a network of satellites that play a key role in the connection of the Earth, still the main haven of humanity, with near and far space. Each of the hops is associated with the four nearest neighbors in orbit and, if necessary, is able to migrate to a more distant satellite.
With the moon, everything is a little more complicated. Given its very low angular velocity, a stable selenium-stationary orbit does not exist. The idea of ​​placing equipment in the inner point of Lagrange was abandoned due to the difficulty of keeping the device in it. Geostationaries have to "lead" surface lunar hop and transmit the signal directly there. Further routing occurs through a network of surface towers and low-orbit satellites.
Stable Lagrange points L4 and L5 turned out to be very useful. Communication stations located in them carry out the majority of packet routing tasks to more distant subnets.
Communication stations themselves "know" where specialized relay long-distance relay nodes and other devices are now located, which, after fulfilling the main mission, have re-qualified. To Mars, the signal is mainly transmitted through L4-L5 stations of the Earth-Moon system, however, in the Sun-Earth and Sun-Mars systems, communication centers are also located at these Lagrange points. They are mainly used when direct signal transmission from the Earth to Mars is impossible due to the presence of the Sun on the way.
The first data centers appeared on the Moon and Mars. The interplanetary CDN service is gaining popularity, but Mars is mainly focused on the development of its own network. The most elderly inhabitants of the Martian settlements, receiving messages from children and grandchildren from the Earth, remember with a smile how they turned on the modem for a short while and waited for mail to be downloaded from the server. Our large solar system continues its movement around the core of our huge galaxy. Life goes on.
Remark: Everything described in the last section is a figment of the author's imagination. I invite everyone to join this fantasy and imagine what the 22nd century Internet will be like. Peace to you space.
Some theory
The idea of ​​this post arose from a friendly discussion on the topic: is it possible to exhaust IPv6 addresses if they start to be used on everything from computers to refrigerators and washing machines? And when will we start settling the moon and mars? And then there are more questions. The average distance from the Earth to the Moon is about 384 thousand km. The signal travels this distance in about 1.3 seconds. Add some delays on the routing equipment and get an approximate ping in a couple of seconds (maybe up to 3 between opposite points of the planets). Running into a counter will not work, but sourcing and even speaking in a voice can come out, albeit with very noticeable brakes.
')
Mars is harder. The distance between the planets varies from 54.6 to 401 million km, which corresponds to the signal transit time from about 3 to more than 22 minutes. And in fact, the upper limit will be even higher. The Sun will be at the most distant points of the orbits between the planets, and it is unlikely that it will “shout” its background with its transmitters. It is necessary to launch the relay at a certain distance from the Sun, which still significantly increases the signal transit time.
The average distance between Earth and Mars is 225 million km (12.5 minutes). Let's try to imagine the classic chain, which occurs when you load the usual modern page, but at a distance of 225 million km. After we enter the address, a request is sent to the DNS service (from Mars to Earth, of course), the IP address is returned. Hooray! After 25 minutes, our Martian computer knows where to send the HTTP request. After another 25 minutes, the browser will receive an html document with links to all css, js files, pictures, etc. and send requests to receive them. The resulting style sheets and scripts can refer to some other images, and God forbid, the site creators guessed to put them in some separate subdomain or use hotlinking (here not only webmasters, but users would also want to burn hotlinkers in hell ). Total, the total load time of one page on the existing scheme today can easily reach one and a half to two hours. And we are considering this ideal variant, in which not a single packet was lost or damaged, which is unlikely at such distances. Really, going to Mars, will you have to forget about the video with cats?
It should be noted that the laying of a network between the planets and spacecraft is not such an invention of science fiction. The development of a protocol that would allow the exchange of data in space began in 1998. And one of the ideological inspirers of the new protocol was Vinton Cerf, who 25 years before had been directly involved in the development of modern Internet protocols. The new group of protocols was named Bundle (English package, bundle, bundle) and became an integral part of the direction of Delay-tolerant networking (networks tolerant to delays). Details of his work have already been dismantled in an article on Habré . I remind you of the key problems that have made the use of modern protocols impossible.
The modern TCP / IP protocol, on which the entire Internet rests, suggests that a data packet is relatively small in size, can be delivered very quickly and does not need long-term storage. If the next route node is not available, the corresponding response is returned, and the packet is removed. In space, where everything is constantly moving, rises and sets, turns and turns, data sessions are often tied to the windows of visibility. The old model of remote space communications provided for direct data transmission from the spacecraft to Earth during the window of view of the transmitting and receiving antennas. The new model assumes that the spacecraft will contain a relay function capable of storing large data packets and transmit them further as soon as the communication window opens. This principle was laid in the new protocol.
The remoteness of the nodes also causes problems with network management. The SNMP management protocol assumes that network nodes respond to the request fairly quickly. The normal response time does not exceed several hundred milliseconds. If a node does not respond for a few seconds, most likely it is not available, and we have a reason to send the packet by another route, if it exists. On a cosmic scale, it may take several hours or even days to fully verify that there are problems on a node. I did not come across information about how you plan to solve this problem. If someone knows, please share.
Another problem, as already mentioned, is the DNS system. Banal domain resolution in IP can take a considerable amount of time. Therefore, it was decided to introduce a two-phase search and the so-called delayed resolution. The first phase is the determination of the desired planet / station and the laying of a route to it, the second is a request to the corresponding local base. Apparently, we should expect that over time, IANA will add the suffix .earth to all root zones, or simply launch separate zones .moon, .mars, etc.
Certain improvement requires security, especially from man-in-the-middle attacks . Therefore, it was decided to introduce additional security measures, including encryption, authentication, etc.
Modern achievements
... in space
Naturally, the first who began to test and put into practice DTN protocols were the space agencies. Thus, different versions of the protocol were introduced to some near and far NASA space programs. A prototype of this protocol was laid in the Mars rovers Spirit and Opportunity , launched back in 2003. By the way, it is worth noting that, as of February 18, 2015, Opportunity is still alive, well, it goes and sends data to Earth.
Another rover, launched much later and using a more modern version of the protocol - Curiosity . This unit, as usual, has the functionality of direct communication with NASA's centers for remote space communications, however most of the data is transmitted through two near-Marc orbiters: the main part is transmitted via the Mars Reconnaissance Orbiter , if necessary, Mars Odyssey is also involved. Thus, two problems are solved at once. First, the device is easier to communicate with the Earth. In the case of a direct connection, Curiosity is available about half a day due to the rotation of Mars. Low-orbiting satellites, in turn, make several full turns per day (for example, the Mars Reconnaissance Orbiter orbital period is less than 2 hours). Thus, if necessary, you can communicate with the landing gear in a reasonable time, transfer control commands and receive data, even when it is on the reverse side of Mars.
In fairness, it is worth mentioning that Spirit and Opportunity kept in touch mostly in the same way, through the same intermediate stations. They were also used by the Phoenix landing gear, which investigated the polar cap of Mars, until the Martian winter took it. Martian winter is dark and full of horrors ...
However, the first serious interplanetary Internet testing was carried out not at all on these missions, but on the EPOXI , which was previously the “mother ship” of the Deep Impact mission. After the separation of the “drummer” in 2005, the device still flew for 2 years in sleep mode, from which it was taken out every six months to test its performance. And in 2007 they decided to repurpose the mission. And one of the new tasks assigned to the device was testing the prototype interplanetary Internet in mid-October - mid-November 2008, during which many images were successfully transferred from the device and back.
Middle Space is also actively involved in testing. The first experiments with the DTN protocol on the International Space Station were carried out by the 18th expedition. And now that year, the experiments are regularly extended. According to the official information on the project page in experiments with DTN, missions took place from 18 to 42 between March 2009 and March 2015. It is likely that the experiments will be extended to further missions.
... and on Earth
Technologies created for space, found and quite terrestrial application. As often happens with good developments, the military became interested in technology. In a battlefield environment, it is more convenient to communicate using a protocol that allows for interruptions in connectivity.
However, science and social sphere also did not stand aside. So, some early adaptation of the protocol was used to observe the movement of African zebras. The sensors, mounted on separate zebras, were equipped with a small storage, GPS and transceiver with a range of about 8 km. The territory on which the observations were made was practically devoid of stationary repeaters, so it was decided to transmit the movement log of animals using a network formed from the zebras themselves, which was called ZebraNet .
A look into the future
In the next 10-15 years, several countries are planning the landing of people on the moon. The EU and China are developing their programs in this direction. The United States plans to conduct tests of the Orion in lunar orbit as part of the preparation of a manned mission to Mars. More vague on the dates of the lunar programs are India, Japan, Russia and Iran. There are also plans to create permanent bases on the Moon and colonize Mars without the possibility of returning to Earth as early as this century. And all these people will need a connection.
The International Consultative Committee on Space Data Communication Systems ( CCSDS ) already now offers all space agencies in the world to install equipment operating with the new protocol on their new automated and manned spacecraft. This will not only make communication with devices more convenient, but also gradually increase the number of routing nodes as the devices complete their main tasks in the mission.
Look into the distant future
Leading scientists of the world have shown all their ingenuity to ensure the most uninterrupted connection between the terranet and the selenite (from the ancient Greek goddess of the Moon - Selena). The Earth is surrounded by a network of entry points to the global interplanetary network, each of which corresponds to one of the geostationary hop - a network of satellites that play a key role in the connection of the Earth, still the main haven of humanity, with near and far space. Each of the hops is associated with the four nearest neighbors in orbit and, if necessary, is able to migrate to a more distant satellite.
With the moon, everything is a little more complicated. Given its very low angular velocity, a stable selenium-stationary orbit does not exist. The idea of ​​placing equipment in the inner point of Lagrange was abandoned due to the difficulty of keeping the device in it. Geostationaries have to "lead" surface lunar hop and transmit the signal directly there. Further routing occurs through a network of surface towers and low-orbit satellites.
Stable Lagrange points L4 and L5 turned out to be very useful. Communication stations located in them carry out the majority of packet routing tasks to more distant subnets.
Communication stations themselves "know" where specialized relay long-distance relay nodes and other devices are now located, which, after fulfilling the main mission, have re-qualified. To Mars, the signal is mainly transmitted through L4-L5 stations of the Earth-Moon system, however, in the Sun-Earth and Sun-Mars systems, communication centers are also located at these Lagrange points. They are mainly used when direct signal transmission from the Earth to Mars is impossible due to the presence of the Sun on the way.
The first data centers appeared on the Moon and Mars. The interplanetary CDN service is gaining popularity, but Mars is mainly focused on the development of its own network. The most elderly inhabitants of the Martian settlements, receiving messages from children and grandchildren from the Earth, remember with a smile how they turned on the modem for a short while and waited for mail to be downloaded from the server. Our large solar system continues its movement around the core of our huge galaxy. Life goes on.
Remark: Everything described in the last section is a figment of the author's imagination. I invite everyone to join this fantasy and imagine what the 22nd century Internet will be like. Peace to you space.
Source: https://habr.com/ru/post/368469/
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