Marshall Eubanks

• Chief Scientist at Space Initiatives Inc

Short-term feasibility of missions to Potentially Hazardous Object 2024 YR4.

Our target is the planet Proxima b orbiting in the habitable zone of Proxima Centauri, the nearest star to the Sun. Laser power beaming will enable the sending of gram-mass picospacecraft on interstellar missions at ~20% of the speed of light, or 0.2 c. At this velocity, the journey would take 21 years, while spending < 3 seconds within 100,000 km...

Presentation to the Lunar Interoperability Forum at the White House Eisenhower Executive Office Building. This presentation deals with the physical basis of the Lunar Reference System, how to improve its ties to the international terrestrial and celestial reference system and includes a proposal to shift the rate of Lunar Coordinated Time (LCT) to...

Paper intended for Living Reviews in Relativity on the types of fundamental physics investigations that a Next Generation Event Horizon Telescope might enable.

We are developing a means of interstellar travel for fast flyby missions combined with optical communications over interstellar range, based on swarms. of picospacecraft accelerated with laser power beaming. • Our plan brings a sequentially-launched string of probes together into a swarm using time-and velocity-on-target dynamic techniques. • Coher...

We highlight the importance of magnetic reconnection at the heliopause, both asone of the key processes driving the interaction between solar and interstellar media,but also as an element of the definition of the heliopause itself. We highlight the mainobservations that have fed the current debates on the definition, location and shapeof the heliop...

Nomadic worlds, i.e., objects not gravitationally bound to any star(s), are of great interest to planetary science and astrobiology. They have garnered attention recently due to constraints derived from microlensing surveys and the recent discovery of interstellar planetesimals. In this paper, we roughly estimate the prevalence of nomadic worlds wi...

The definition of the Double Jupiter Gravitational Assist trajectory. It's effectiveness at escaping the Solar System, chasing and catching interstellar objects 1I/'Oumuamua or 2I/Borisov.

Ballistic penetrators, hitchhikers dropped from a carrier space- craft offer an economical way to study and instrument a large number of sites, deliverying small swarms of instrumented probes across a target of interest in even the roughest terrain.

We highlight the importance of magnetic reconnection at the heliopause, both as one of the key processes driving the interaction between solar and interstellar media, but also as an element of the definition of the heliopause itself. We highlight the main observations that have fed the current debates on the definition, location and shape of the he...

The source-frequency phase-referencing (SFPR) technique has been demonstrated to have great advantages for mm-VLBI observations. By implementing simultaneous multi-frequency receiving systems on the next-generation Event Horizon Telescope (ngEHT) antennas, it is feasible to carry out a frequency phase transfer (FPT) which could calibrate the non-di...

The source-frequency phase-referencing (SFPR) technique has been demonstrated to have great advantages for mm-VLBI observations. By implementing simultaneous multi-frequency receiving systems on the next generation Event Horizon Telescope (ngEHT) antennas, it is feasible to carry out a frequency phase transfer (FPT) which could calibrate the non-di...

Nomadic worlds are objects not bound to any star(s), and are of great interest to planetary science and astrobiology. They have garnered attention recently on account of their detection in microlensing surveys and also from the recent discovery of interstellar planetesimals. In this paper, we evaluate the prevalence of nomadic worlds with radii of...

Lunar surface temperatures in any region receiving sunlight are subject to large temperature variations, which create problems for any equipment located on the lunar surface. The surface temperature is dominated by radiative effects on the thin top layer, only a few cm thick, which has a very very low thermal conductivity. This thin layer effective...

Comet C/2014 UN$_{271}$, alternative designation 'BB' after its discoverers 'Bernardinelli/Bernstein', and commonly referred to as UN$_{271}$, is an extreme case on two fronts, firstly its solar distance on discovery ($>$ 29 au) and secondly the size of its nucleus (137$\pm$ 15 km). With an aphelion distance of $\sim$33,000 au (w.r.t. the solar sys...

Underground lakes of liquid water on the Moon require a reservoir of underground water, a source of heat, and a barrier sufficient to stop the water from being lost to space over geologic time. Subsurface ice layers will block the diffusion of deeper liquid water, so subterranean `lakes’’ could be present underneath any region with surface or subsu...

The lunar surface is often assumed to be entirely static except for tidal deformations and meteorite impacts, but recent studies of lunar compressional faults show that the Moon remains tectonically active. In an extensive search of the entire the Gruithuisen Dome Region, we found a depression South of the Gamma Dome we call the Gamma Pit, which, a...

The lunar surface is often assumed to be entirely static except for tidal deformations and meteorite impacts, but recent studies of lunar compressional faults show that the Moon remains tectonically active. In an extensive search of the entire the Gruithuisen Dome Region, we found a depression South of the Gamma Dome we call the Gamma Pit, which, a...

To settle the question of the nature of the interstellar object 1I/’Oumuamua requires in-situ observations via a spacecraft, as the object is already out of range of existing telescopes. Most previous proposals for reaching 1I/’Oumuamua using near-term technologies are based on the Solar Oberth Manoeuvre (SOM), as trajectories without the SOM are g...

Presentation to the Breakthrough Initiatives | University of Luxembourg "Sundiver" workshop on Fast, Low-Cost, Interplanetary Sailcraft Science Missions

In this paper, we propose using laser-driven light-sail probes to implement quick-reaction missions to intercept PHOs approaching Earth, with an initial test of this capability using the upcoming close approach of Asteroid 99942 Apophis.

We report on an apparently active tectonic area we have discovered in the Gruithuisen Dome Region of the Moon.

To settle the question of the nature of the interstellar object 1I/'Oumuamua requires in-situ observations via a spacecraft, as the object is already out of range of existing telescopes. Most previous proposals for reaching 1I/'Oumuamua using near-term technologies are based on the Solar Oberth Manoeuvre (SOM), as trajectories without the SOM are g...

This topical white paper wishes to recommend to the BPS decadal survey the state-of-the-art objectives of fundamental physics and lunar science, that are enabled by next generation single, large diameter CCRs deployed by means of NASA-CLPS missions, through the international Artemis Accords, the EL3 lunar program and the LGN during the decade 2023-...

Presentation to Lunar Surface Science Workshop introducing the concept of Lunar Adjusted Time, analogous to IAT/UTC.

The recently discovered first high velocity hyperbolic objects passing through the Solar System, 1I/’Oumuamua and 2I/Borisov, have raised the question about near term missions to Interstellar Objects. In situ spacecraft exploration of these objects will allow the direct determination of both their structure and their chemical and isotopic compositi...

The radio environment of the Moon at low frequencies, particularly in lunar polar regions and the permanently shadowed regions (PSR) found there, is relatively poorly explored and may contain some novel features. In addition, these areas of the Moon, shielded from the natural and artificial emissions of the Earth, and the natural radio emissions of...

The radio environment of the Moon at low frequencies, particularly in lunar polar regions and the permanently shadowed regions (PSR) found there, is relatively poorly explored and may contain some novel features. In addition, these areas of the Moon, shielded from the natural and artificial emissions of the Earth, and the natural radio emissions of...

The upcoming decade offers multiple opportunities at extending science from the Lunar Laser Ranging (LLR) experiment that would result in unprecedented data precision, which may enable detection of subtle signatures required to understand the dynamics of the Earth-Moon system and the deep lunar interior.

1I/'Oumuamua (or 1I) and 2I/Borisov (or 2I), the first InterStellar Objects (ISOs) discovered passing through the solar system, have opened up entirely new areas of exobody research. Finding additional ISOs and planning missions to intercept or rendezvous with these bodies will greatly benefit from knowledge of their likely orbits and arrival rates...

Fundamental scientific objectives concerning the surface and subsurface material and dynamics of the Moon are the drivers for the use and advancement of penetrators, which emplace a suite of scientific instruments by impact into a planetary surface, typically at velocities of dozens to hundreds of meters per second. Small lunar penetrators are pois...

The potential detection of phosphine in the atmosphere of Venus has reignited interest in the possibility of life aloft in this environment. If the cloud decks of Venus are indeed an abode of life, it should reside in the “habitable zone” between ∼50–60 km altitude, roughly coincident with the middle cloud deck, where the temperature and pressure (...

The recent detection of phosphine in the atmosphere of Venus has reignited interest in the possibility of life aloft in this environment. If the cloud decks of Venus are indeed an abode of life, it should reside in the "habitable zone" between ~50 to ~60 km altitude, roughly coincident with the middle cloud deck, where the temperature and pressure...

Lunar retro-reflector arrays (LRAs) consisting of corner-cube reflectors (CCRs) placed on the nearside of the Moon during the Apollo era have demonstrated their longevity, cost-effectiveness, ease of deployment, and most importantly their interdisciplinary scientific impact through the ongoing lunar laser ranging (LLR) experiment. The human explora...

With current technology prediction errors in Low Earth Orbit (LEO) are frequently greater than the estimated separation distance between objects undergoing conjunction. Current predictions are thus frequently false alarms, and real collisions have been missed resulting in expensive losses. The February 2009 collision between the active Iridium 33 a...

The Lunar Laser Ranging (LLR) experiment has accumulated 50 years of range data of improving accuracy from ground stations to the laser retroreflector arrays (LRAs) on the lunar surface. The upcoming decade offers several opportunities to break new ground in data precision through the deployment of the next generation of single corner-cube lunar re...

Two extrasolar objects, 1I/'Oumuamua, 2I/Borisov, have passed through our home system in just the last three years. Such interstellar objects provide a previously unforeseen chance to directly sample physical material from other stellar systems. By analyzing these interlopers, we can acquire data and deduce information about their planetary system...

The recent discovery of the first confirmed Interstellar Objects (ISOs) passing through the Solar System on clearly hyperbolic objects opens the potential for near term ISO missions, either to the two known objects, or to similar objects found in the future. Such ISOs are the only exobodies we have a chance of accessing directly in the near future....

Both the radio International Celestial Reference Frame (ICRF) and the optical Gaia Celestial Reference Frame (Gaia-CRF2) are derived from observations of jets produced by the Super Massive Black Holes (SMBH) powering active galactic nuclei and quasars. These jets are inherently subject to change and will appear different at different observing freq...

The large constellations of spacecraft planned for use in cislunar space (on the Lunar surface, in Lunar orbit, and in the vicinity of the Lunar Gateway) require new solutions for positioning, navigation and timing (PNT). Here, I describe COMPASS (Combined Observational Methods for Positional Awareness in the Solar System), a spacecraft navigation...

In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/‘Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation of 1I would be of extraordinary scientific value. Previous studies have demonstrated that a mi...

Both the radio International Celestial Reference Frame (ICRF) and the optical Gaia Celestial Reference Frame (Gaia-CRF2) are derived from observations of jets produced by the Super Massive Black Holes (SMBH) powering active galactic nuclei and quasars. These jets are inherently subject to change and will appear different at different observing freq...

The large constellations of spacecraft planned for use incislunar space (on the Lunar surface, in Lunar orbit, andin the vicinity of the Lunar Gateway) require new solu-tions for positioning, navigation and timing (PNT). Here,I describe COMPASS (Combined Observational Methodsfor Positional Awareness in the Solar System), a space-craft navigation sy...

We are developing a unifed ``LunaCell'' system that can be deployed onto the lunar surface either with or, better yet, in advance of, a crewed or robotic new landing. Upon deployment (which could be done in stages, with a penetrator deployment augmented by deployments from landers or rovers) the LunaCell system will provide the following services:...

The detection of interstellar bodies passing near the Sun offers the opportunity to observe not just objects similar to those in the solar system, but also unfamiliar objects without solar system analogues. Here I show that Asymptotic Giant Branch (AGB) stellar evolution may lead to the creation, out of stardust, of substantial numbers of nomadic P...

The large constellations of spacecraft planned for use in cislunar space (on the Lunar surface, in Lunar orbit, and in the vicinity of the Lunar Gateway) require new solutions for positioning and navigation. COMPASS (Combined Observational Methods for Positional Awareness in the Solar System) is a spacecraft navigation system being developed to pro...

The miniaturization of electronic and mechanical components has allowed for an unprecedented downscaling of spacecraft size and mass. Today, spacecraft with a mass between 1 to 10 grams, called AttoSats, have been developed and operated in space. Due to their small size, they introduce a new paradigm in spacecraft design, relying on agile developme...

In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/'Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation of 1I would be of extraordinary scientific value. Previous studies have demonstrated that a mi...

This is a modified version of the original paper which now additionally examines the relationship between total DeltaV required to get to 'Oumuamua as a function of perihelion distance of the Solar Oberth. The results show that a Solar Oberth at 6 Solar radii from the centre of the sun (5 Solar radii from the surface) leads to lower deltaV values a...

The recent discovery of the first high velocity hyperbolic object passing through the Solar System, 1I/’Oumuamua, opens the potential for a near term missions to interstellar objects. Feng & Jones noted that the incoming velocity “at infinity” (v-infinity) of 1I is close to the velocity of the Pleiades dynamical stream (or Local Association), sugge...

The nature of 1I/'Oumuamua (henceforth, 1I), the first interstellar object known to pass through the solar system, remains mysterious. Feng \& Jones noted that the incoming 1I velocity vector "at infinity" ($\textbf{v}_{\infty}$) is close to the motion of the Pleiades dynamical stream (or Local Association), and suggested that 1I is a young object...

The nature of 1I/'Oumuamua (henceforth, 1I), the first interstellar object known to pass through the solar system, remains mysterious. Feng & Jones noted that the incoming 1I velocity vector "at infinity" (v ∞) is close to the motion of the Pleiades dynamical stream (or Local Association), and suggested that 1I is a young object ejected from a star...

In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/'Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation of 1I would be of extraordinary scientific value. Previous studies have demonstrated that a mi...

In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/'Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation of 1I would be of extraordinary scientific value. Previous studies have demonstrated that a mi...

The search for life in the universe is a major theme of astronomy and astrophysics for the next decade. Searches for technosignatures are complementary to searches for biosignatures, in that they offer an alternative path to discovery, and address the question of whether complex (i.e. technological) life exists elsewhere in the Galaxy. This approac...

The first definitely interstellar object 1I/'Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from other star systems. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess veloci...

The discovery of pulsars with masses of ∼ 2 solar masses (2 M ⊙) provides strong support for the existence of strange quark matter in nature [1]. The discovery of ultra-dense pulsar planets [2] indicates that strange quark matter objects need not be gravitationally confined and supports the hypothesis that strange quark matter is a stable state of...

Chameleon fields are a way to "hide" a scale gravitational field, avoiding the stringent constant on static Brans Dicke scalar fields. Because chameleon fields are hidden in ordinary matter by an increase in the mass of the chameleon, the group velocity of the field is lowered, which means that non-relativistic vibrating or moving masses could pote...

A Schumann Resonance is an electromagnetic oscillation excited in a closed waveguide formed by multiple reflecting layers at or near the surface of a planetary body. The waveguide, for spherical bodies with uniform reflecting layers, is a resonant cavity with a fundamental wavelength ∼ the circumference of the body. The terrestrial Schumann Resonan...

The Deep Space Gateway (DSG) proposed for cis-lunar space offers an opportunity to both improve tests of fundamental physics and to develop chronometric navigation techniques for the human exploration of Mars and beyond. Here we outline how the DSG, equipped with highly accurate optical atomic clocks and optical phase coherent links with the Earth...

The first definitely interstellar object 1I/'Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from other star systems. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess veloci...

The first definitely interstellar object 1I/'Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from other star systems. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess veloci...

The best current approximation to an inertial reference frame is provided by Very Long Baseline Interferometry (VLBI) observations of extragalactic radio sources with red shifts ( z ) up to 3.8. The stability of the resulting reference frame directly depends on the amount of any secular changes in the observed source positions. Two types of potenti...

Tectonic motions will, in general, change the orientation as well as the length of baselines used in Very Long Baseline Interferometry (VLBI), and will thus cause slow divergences between Earth orientation results obtained with different VLBI networks, as well as between VLBI results and those obtained by Satellite Laser Ranging (SLR) and Lunar Las...

A human presence on Mars will, with current technology, require 6 to 9 month journeys in deep space to go between between the Earth and Mars, and also to return. There have been proposals both to bring asteroidal resources to cislunar space for use by astronauts in these journeys, and to conduct them using Mars cyclers, spacecraft on repeating orbi...

We show that the core programmatic goals of the Asteroid Impact Mission (AIM) can be met with a relatively low cost Femtospacecraft Asteroid Impact Mission (FAIM), a 6-U ``Bradbury'' CubeSat deploying a swarm of dozens of 50-gm ``Pixie'' femtospacecraft. FAIM would also provide scientific information about the Didymos system, and an opportunity to...

The closest exoplanet is likely not to be Proxima Centauri b, but an as yet unknown nomadic exoplanet. I will describe how densely populated near-interstellar space is likely to be, and what steps should be taken to find our nearest neighbors.

Extra-terrestrial space elevators are technically feasible with current materials and can be part of a transportation network to fulfill NASA's strategic exploration goals for the next three decades.

A Schumann Resonance is an electromagnetic oscillation in a closed waveguide formed by the ionosphere and the surface or interior of a planetary body, the waveg-uide being a resonant cavity with a fundamental wavelength of ∼ the circumference of the body. The terrestrial Schumann Resonance is formed by the cavity between the ionosphere and the surf...

Of the possible near-term space elevator deployments (Earth, Moon, Mars), a Lunar Space Elevator (LSE) is undoubtedly the most technically feasible. The proposed LSE Infrastructure (LSEI), proposed as the first space elevator on any celestial body, would be a very long tether extending from the lunar Surface, through the Earth-Moon Lagrange L1 poin...

The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered in near-term plans for space exploration, perhaps because a terrestrial elevator would not be possible without considerable improvements in tether material. A Lunar Space Elevator (LSE), however, can be built with current technology using commercially av...

The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered in near-term plans for space exploration, perhaps because a terrestrial elevator would not be possible without considerable improvements in tether material. A Lunar Space Elevator (LSE), however, can be built with current technology using commercially av...

We present our ongoing investigation of the use of U.S-produced atmospheric and oceanic angular momentum (AAM and OAM) estimates to improve the determination of near real-time Earth rotation and polar motion parameters and their short-term predictions. Previous investigations provided evidence that the use of AAM and OAM data sets could improve sho...

Extended Abstract for the ASE Earth and Space Conference April, 2016 – Orlando, FL.

Accepted by the Icarus Interstellar Starship Congress 2015 for presentation Friday, September 4th, 2015, Philadelphia, Pennsylvania.

Presentation, August 9, 2015, to the Northern Virginia Astronomy Club at George Mason University Fairfax, Virginia.

Presentation for Asteroid Day Talk at George Mason University, June 30, 2015.

Gravitational microlensing has revealed an extensive population of ``nomadic'' planets not orbiting any star, with Jupiter-mass nomads being more populous than main sequence stars. Except for distant objects discovered through microlensing, and hot, young nomads found near star formation regions, to date only a small number of nomad candidates have...

Both the scientific exploration and the prospecting of resources of Near Earth Asteroids (NEA) would benefit from visits to multiple bodies by a single spacecraft, for which a photon sail (typically called a solar sail when used in the sunlight) offers many advantages. However, it is not possible to truly turn off the thrust from a sail in full sun...

Quark nuggets, balls of dense Color-Flavor Locked (CFL) superconducting quark matter, have been proposed as a possible explanation for the cosmological and galactic Dark Matter (DM). These nuggets, created at the Quantum ChromoDynamics (QCD) phase transition in the first microseconds of the universe, would, in these theories, remain prevalent at th...

Gravitational microlensing surveys reveal the existence of a substantial population of nomadic planets, bodies not in orbit around any star. The microlensing results also indicate that the mass spectrum of these objects follow power laws with smaller nomadic planets being more common that Jupiter-sized bodies. Near-by nomadic planets are thus likel...

Asteroid mining will require evaluation not only of the surface geology of a candidate asteroid, but ideally also a view of the interior of the body. This ability is important for either mission concept currently under consideration for the NASA Asteroid Retrieval Mission (ARM), and also for asteroid prospecting (the evaluation of asteroids as mini...

This document provides a graph representing the current constraints on Compact Ultra-Dense Objects (CUDOs). It is intended to be updated as new constraints are published or found.