Interstellar Communication Network. I. Overview and Assumptions

Abstract

It has recently been suggested in this journal by Benford (2019) that "Lurkers" in the form of interstellar exploration probes could be present in the solar system. Similarly, extraterrestrial intelligence could send long-lived probes to many other stellar systems, to report back science and surveillance. If probes and planets with technological species exist in more than a handful of systems in our galaxy, it is beneficial to use a coordinated communication scheme. Due to the inverse square law, data rates decrease strongly for direct connections over long distances. The network bandwidth could be increased by orders of magnitude if repeater stations (nodes) are used in an optimized fashion. This introduction to a series of papers makes the assumptions of the communication scheme explicit. Subsequent papers will discuss technical aspects such as transmitters, repeaters, wavelengths, and power levels. The overall purpose is to gain insight into the physical characteristics of an interstellar communication network, allowing us to describe the most likely sizes and locations of nodes and probes.

Stellar Gravitational Lens Engineering for Interstellar Communication and Artifact SETI

“…A stellar relay can be designed to use the entire Einstein ring of the Sun if the relay spacecraft is on-axis, or transmit at only a single point on the Einstein ring. For simplicity we only consider on-axis broadcasting using the entire annular Einstein ring in this work, though an off-axis arrangement using only part of the Einstein ring follows similar proofs and obtains similar results (Hippke 2020). Figure 1 shows a schematic overview of a characteristic on-axis stellar relay using the Sun's entire Einstein ring.…”

“…An interstellar communication requires extraordinarily high directional gain or transmitting power to ensure that information packets can be reconstructed after steaming through deep space. Over the past forty years, various proposals have suggested using the gravitational lensing effect of a star like our Sun to focus outgoing or incoming transmissions, dramatically supplementing the gain of a transmitting relay spacecraft (Eshleman 1979a;Maccone 2011;Hippke 2020). A similar arrangement, like that proposed in the FOCAL mission, can focus photons from the distant universe onto a space telescope, dramatically increasing the magnification and effective collecting area of the system (Maccone 2010).…”

“…spacecraft might remotely explore or monitor our solar system, but must maintain communications across interstellar distances to be scientifically productive. Alternatively, given the daunting challenges of direct interstellar communication, a broadcasting spacecraft using the gravitational lens of the Sun as described in Maccone (2011) and Hippke (2020) could facilitate interstellar communication as part of a broader communication network in which the Sun is just one node.…”

Searching for interstellar quantum communications

“…Yet, only 33 years after Subotowicz, Neutrino communications have now been shown at a basic level (0.1 bits/s) in a practical experiment (Stancil et al 2012). However, communication with Neutrinos has a multitude of practical disadvantages over photons, which makes them unattractive for any conceivable rational being (Hippke 2018a). In practice, quantum Neutrino communication is unrealistically difficult due to their small cross-section, which makes it virtually impossible to detect entangled pairs (Blasone et al 2009).…”

Astrometric study of Gaia DR2 stars for interstellar communication

“…Considering the potential limitations of observational facilities and computational resources inversely at ETI side, it would be more advantageous to increase the energy flux of our outgoing signals. Here one of the solid options is to reduce the beam opening angle Θ (e.g., Benford et al 2010, see also Hippke 2019). For example, using a phased array with an effective diameter comparable to the core station of SKA2, we can realize Θ ∼ 0.8"(λ/4 cm)(L/5 km) −1 .…”