As our exploration of the solar system continues, we’re going to feel the need for a more effective system of communication. Currently, what we use for interplanetary communication yields poor results. There is significant loss of data packets, resulting in poor quality images from our probes and crafts. The rate of transmittance is less than 1000 bits per second – about 200 times slower than the transfer rate of a standard computer on earth. Not surprising then, that scientists globally are pursuing the idea of an efficient network communication system across planets.
Plans have been made and partially implemented to bring the idea of an interplanetary internet into reality. Plus, there are special interest groups already actively pushing for the idea. Here is how interplanetary internet is supposed to work.
The idea of an interplanetary data network was conceived back with the internet actually, with its development, of course, still ongoing. The chief purpose here is to develop a deep space wireless network for efficient data transfers. The three primary components necessary for an effective interplanetary internet are as follows:
Receiving/Transmitting antennas on the earth
Satellite constellations around other planets
Suitable Internet protocol
The main difference in the internet on the earth and an interplanetary one is the protocol. Currently the TCP/IP protocol drives internet on the earth. The protocol assumes uninterrupted data transfers – it has little tolerance for interruptions or loss of data packets. But interplanetary internet will have to account for a significant loss of data packets. It will have to continue uninterrupted in spite of major interruptions. While TCP/IP dumps data packets which it cannot deliver, the new protocol will need wait for the channel to clear and deliver the interrupted data. It must also ignore the noise that will be added to the signals due to the large distances involved.
One of the proposed protocols to achieve this is the Parcel transfer protocol (PTP) – our path to a Disruption Tolerant Network, or DTN. A DTN is the only way to effectively establish network connectivity in space.
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The infrastructure for an interplanetary internet would consist of receiver antennas and satellite transmitters. NASA built the Deep Space Network as a part of its project to establish an interplanetary network, with facilities built in California, Australia and Spain. Each facility is equipped with an array of three antennas which together make up the Deep Space Network. Once our interplanetary internet system is in place, these antennas will probably be responsible for receiving data from the transmitters as well as sending data to the equipment present in the deep space.
A near-term objective of this project will be to establish internet on Mars. This involves pointing the deep space network antennas towards the red planet, and putting several satellites into orbit around Mars. A plan has been made to put six microsatellites and one large satellite into the Martian orbit. This satellite mission was supposed to be carried out in 2009, but was scrapped due to budget constraints.
The proposed functioning of the interplanetary internet is quite simple, once the infrastructure is in place. There must be several microsatellites and a large satellite orbiting a planet to establish internet connectivity. The microsatellites would act as relays from the surface of the planet to the larger satellite (. These would capture detailed information from the surface. These microsatellites can also collect data from other sources such as spacecraft. The larger satellite, after collecting data from the microsatellites, would transmit this data back to the antennas on the earth. In this way, the larger satellite would act as an information hub for the data transfer. However for this system to be successful, a functional internet protocol is crucial.
The idea of an interplanetary internet faces plenty of challenges. The most daunting one is the distance. The distances involved will be in the millions of kilometres. At the speed of light, data packets would still take from minutes to hours to reach their destination. This renders real time communication nearly impossible. So we’re probably going to have to live with cached versions of Earth’s internet data, that will be updated periodically for our Mars colonies to consume.
Loss of data is an additional problem caused by the large distances. With obstructions in the line of sight, continuous data transmissions aren’t going to be a possibility. Introduction of noise into the signals will also be an issue.
Of course, another disadvantage will be serviceability. In case of damage or malfunctioning of the deep space data hubs, it would be nearly impossible to repair these satellites. This would mean that the maintenance costs of such a network would be astronomical. Ensuring truly ‘space-grade’ reliability of all components will therefore be necessary before any such mission can be realised.
The idea of an effective interplanetary internet, on the lines of how internet on Earth works today, will be brought into reality sooner than one might expect. Expect internet on Mars to be established within the next decade. And hopefully, before the turn of the century, we can expect many planets linked to the earth in the same way.