arXiv subjects

Andreas M. Hein

Publications and source records attributed to Andreas M. Hein.

33 records · Page 2Linked to original sources

arXiv2020

Exobodies in Our Back Yard: Science from Missions to Nearby Interstellar Objects

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. This White Paper focuses on the science possible from in situ spacecraft exploration of nearby ISOs. Such spacecraft missions are technically possible now and are suitable potential missions in the period covered by the 2023-2032 Decadal Survey. Spacecraft missions can determine the structure and the chemical and isotopic composition of ISO in a close flyby coupled with a small sub-probe impactor and either a mass spectrometer or a high resolution UV spectrometer; this technology will also be useful for fast missions to TransNeptune Objects (TNOs) and long period comets. ISO exploration holds the potential of providing considerable improvements in our knowledge of galactic evolution, of planetary formation, and of the cycling of astrobiologically important materials through the galaxy.

astro-ph.IM↗

arXiv2020

The Cathedral and the Starship: Learning from the Middle Ages for Future Long-Duration Projects

A popular analogue used in the space domain is that of historical building projects, notably cathedrals that took decades and in some cases centuries to complete. Cathedrals are often taken as archetypes for long-term projects. In this article, I will explore the cathedral from the point of view of project management and systems architecting and draw implications for long-term projects in the space domain, notably developing a starship. I will show that the popular image of a cathedral as a continuous long-term project is in contradiction to the current state of research. More specifically, I will show that for the following propositions: The cathedrals were built based on an initial detailed master plan; Building was a continuous process that adhered to the master plan; Investments were continuously provided for the building process. Although initial plans might have existed, the construction process took often place in multiple campaigns, sometimes separated by decades. Such interruptions made knowledge-preservation very challenging. The reason for the long stretches of inactivity was mostly due to a lack of funding. Hence, the availability of funding coincided with construction activity. These findings paint a much more relevant picture of cathedral building for long-duration projects today: How can a project be completed despite a range of uncertainties regarding loss in skills, shortage in funding, and interruptions? It is concluded that long-term projects such as an interstellar exploration program can take inspiration from cathedrals by developing a modular architecture, allowing for extensibility and flexibility, thinking about value delivery at an early point, and establishing mechanisms and an organization for stable funding.

econ.GN↗

arXiv2020

Project Lyra: Catching 1I/'Oumuamua -- Using Laser Sailcraft in 2030

Discovered in October 2017, the interstellar object designated 1I/'Oumuamua was the first such object to be observed travelling through our solar system. 1I/'Oumuamua has other characteristics never seen before in a celestial body and in-situ observations and measurements would be of extraordinary scientific value. Previous studies have demonstrated the viability of spacecraft trajectories to 'Oumuamua using chemical propulsion with a Solar Oberth burn at a perihelion as low as a few solar radii. In addition to chemical propulsion, there is also the possibility of missions involving light sails accelerated by the radiation pressure of a laser beam from a laser located on Earth. Based on a scaled-down Breakthrough Starshot beaming infrastructure, interplanetary missions and missions to the outer solar system have been proposed using lower sailcraft speeds of 0.001c relaxing the laser power requirements (3-30 GW for 1-100 kg spacecraft) and various other mission constraints. This paper uses the OITS trajectory simulation tool, which assumes an impulsive $Δ$V increment, to analyze the trajectories which might be followed by a sailcraft to 'Oumuamua, with a launch in the year 2030 and assuming it has already been accelerated to a maximum speed of 300km/s (approx. 0.001c) by the laser. A minimum flight duration of 440 days for a launch in July 2030 is found. The intercept would take place beyond 82 AU. We conclude that the possibility of launching a large number of spacecraft and reaching 1I much faster than chemical propulsion would circumvent several disadvantages of previously proposed mission architectures.

astro-ph.EP↗

arXiv2020

Near-Term Self-replicating Probes -- A Concept Design

Self-replicating probes are spacecraft with the capacity to create copies of themselves. Self-replication would potentially allow for an exponential increase in the number of probes and thereby drastically improve the efficiency of space exploration. Despite this potential, an integrated assessment of self-replicating space probes has not been presented since the 1980s, and it is still unclear how far they are feasible. In this paper, we propose a concept for a partially self-replicating probe for space exploration based on current and near-term technologies, with a focus on small spacecraft. The purpose is to chart a path towards self-replication with near-term benefits, rather than attempting full self-replication. For this reason, components such as microchips and other microelectronic components are brought with the initial probe and are not replicated. We estimate that such a probe would be capable of replicating 70% of its mass. To further increase this percentage, we identify technology gaps that are promising to address. We conclude that small-scale, partially self-replicating probes are feasible near-term. Their benefits would play out in exploration missions requiring roughly more than a dozen of probes.

physics.pop-ph↗

arXiv2020

World ships: Feasibility and Rationale

World ships are hypothetical, large, self-contained spacecraft for crewed interstellar travel, taking centuries to reach other stars. Due to their crewed nature, size, and long trip times, the feasibility of world ships faces an additional set of challenges compared to interstellar probes. Despite their emergence in the 1980s, most of these topics remain unexplored. This article revisits some of the key feasibility issues of world ships. First, definitions of world ships from the literature are revisited and the notion of world ship positioned with respect to similar concepts such as generation ships. Second, the key question of population size is revisited in light of recent results from the literature. Third, socio-technical and economic feasibility issues are evaluated. Finally, world ships are compared to potential alternative modes of crewed interstellar travel. Key roadblocks for world ships are the considerable resources required, shifting its economic feasibility beyond the year 2300, and the development of a maintenance system capable of detecting, replacing, and repairing several components per second. The emergence of alternative, less costly modes of crewed interstellar travel at an earlier point in time might render world ships obsolete.

physics.pop-ph↗

arXiv2020

Energy Limits to the Gross Domestic Product on Earth

Once carbon emission neutrality and other sustainability goals have been achieved, a widespread assumption is that economic growth at current rates can be sustained beyond the 21st century. However, even if we achieve these goals, this article shows that the overall size of Earth's global economy is facing an upper limit purely due to energy and thermodynamic factors. For that, we break down global warming into two components: the greenhouse gas effect and heat dissipation from energy consumption related to economic activities. For the temperature increase due to greenhouse gas emissions, we take 2 °C and 5 °C as our lower and upper bounds. For the warming effect of heat dissipation related to energy consumption, we use a simplified model for global warming and an extrapolation of the historical correlation between global gross domestic product (GDP) and primary energy production. Combining the two effects, we set the acceptable global warming temperature limit to 7 °C above pre-industrial levels. We develop four scenarios, based on the viability of large-scale deployment of carbon-neutral energy sources. Our results indicate that for a 2% annual GDP growth, the upper limit will be reached at best within a few centuries, even in favorable scenarios where new energy sources such as fusion power are deployed on a massive scale. We conclude that unless GDP can be largely decoupled from energy consumption, thermodynamics will put a hard cap on the size of Earth's economy. Further economic growth would necessarily require expanding economic activities into space.

physics.soc-ph↗

arXiv2019

AttoSats: ChipSats, other Gram-Scale Spacecraft, and Beyond

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, AttoSats, have been developed and operated in space. Due to their small size, they introduce a new paradigm in spacecraft design, relying on agile development, rapid iterations, and massive redundancy. However, no systematic survey of the potential advantages and unique mission concepts based on AttoSats exists. This paper explores the potential of AttoSats for future space missions. First, we present the state of the art of AttoSats. Next, we identify unique AttoSat characteristics and map them to future mission capabilities. Finally, we go beyond AttoSats and explore how smart dust and nano-scale spacecraft could allow for even smaller spacecraft in the milligram range: zepto- and yocto spacecraft.

astro-ph.IM↗

arXiv2019

Project Lyra: Catching 1I/'Oumuamua - Mission Opportunities After 2024

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 mission to 1I/'Oumuamua is feasible using current and near-term technologies however with an anticipated launch date of 2020-2021, this is too soon to be realistic. This paper aims at addressing the question of the feasibility of a mission to 1I/'Oumuamua in 2024 and beyond. Using the OITS trajectory simulation tool, various scenarios are analyzed, including a powered Jupiter flyby and Solar Oberth maneuver, a Jupiter powered flyby, and more complex flyby schemes including a Mars and Venus flyby. With a powered Jupiter flyby and Solar Oberth maneuver, we identify a trajectory to 1I/'Oumuamua with a launch date in 2033, a total velocity increment of 18.2 km/s, and arrival at 1I/'Oumuamua in 2048. With an additional deep space maneuver before the powered Jupiter flyby, a trajectory with a launch date in 2030, a total velocity increment of 15.3 km/s, and an arrival at 1I/'Oumuamua in 2052 were identified. Both launch dates would provide over a decade for spacecraft development, in contrast to the previously identified 2020-2021 launch dates. Furthermore, the distance from the Sun at the Oberth burn is at 5 Solar radii. This results in heat flux values, which are of the same order of magnitude as for the Parker Solar Probe. We conclude that a mission to 1I/'Oumuamua is feasible, using existing and near-term technologies and there is sufficient time for developing such a mission.

physics.space-ph↗

arXiv2018

Artificial Intelligence for Interstellar Travel

The large distances involved in interstellar travel require a high degree of spacecraft autonomy, realized by artificial intelligence. The breadth of tasks artificial intelligence could perform on such spacecraft involves maintenance, data collection, designing and constructing an infrastructure using in-situ resources. Despite its importance, existing publications on artificial intelligence and interstellar travel are limited to cursory descriptions where little detail is given about the nature of the artificial intelligence. This article explores the role of artificial intelligence for interstellar travel by compiling use cases, exploring capabilities, and proposing typologies, system and mission architectures. Estimations for the required intelligence level for specific types of interstellar probes are given, along with potential system and mission architectures, covering those proposed in the literature but also presenting novel ones. Finally, a generic design for interstellar probes with an AI payload is proposed. Given current levels of increase in computational power, a spacecraft with a similar computational power as the human brain would have a mass from dozens to hundreds of tons in a 2050-2060 timeframe. Given that the advent of the first interstellar missions and artificial general intelligence are estimated to be by the mid-21st century, a more in-depth exploration of the relationship between the two should be attempted, focusing on neglected areas such as protecting the artificial intelligence payload from radiation in interstellar space and the role of artificial intelligence in self-replication.

physics.pop-ph↗

arXiv2018

Project Lyra: Sending a Spacecraft to 1I/'Oumuamua (former A/2017 U1), the Interstellar Asteroid

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 velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for a mission to 1I/'Oumuamua and potential similar objects. Launching a spacecraft to 1I/'Oumuamua in a reasonable timeframe of 5-10 years requires a hyperbolic solar system excess velocity between 33 to 76 km/s for mission durations between 30 to 5 years. Different mission durations and their velocity requirements are explored with respect to the launch date, assuming direct impulsive transfer to the intercept trajectory. For missions using a powered Jupiter flyby combined with a solar Oberth maneuver using solid rocket boosters and Parker Solar Probe heat shield technology, a Falcon Heavy-class launcher would be able to launch a spacecraft of dozens of kilograms towards 1I/'Oumuamua, if launched in 2021. An additional Saturn flyby would allow for the launch of a New Horizons-class spacecraft. Further technology options are outlined, ranging from electric propulsion, and more advanced options such as laser electric propulsion, and solar and laser sails. To maximize science return decelerating the spacecraft at 'Oumuamua is highly desirable, due to the minimal science return from a hyper-velocity encounter. Electric and magnetic sails could be used for this purpose. It is concluded that although reaching the object is challenging, there seem to be feasible options based on current and near-term technology.

physics.space-ph↗

arXiv2018

A Techno-Economic Analysis of Asteroid Mining

Asteroid mining has been proposed as an approach to complement Earth-based supplies of rare earth metals and supplying resources in space, such as water. However, existing studies on the economic viability of asteroid mining have remained rather simplistic and do not provide much guidance on which technological improvements would be needed for increasing its economic viability. This paper develops a techno-economic analysis of asteroid mining with the objective of providing recommendations for future technology development and performance improvements. Both, in-space resource provision such as water and return of platinum to Earth are considered. Starting from first principles of techno-economic analysis, gradually additional economic and technological factors are added to the analysis model. Applied to mining missions involving spacecraft reuse, learning curve effect, and multiple spacecraft, their economic viability is assessed. A sensitivity analysis with respect to throughput rate, spacecraft mass, and resource price is performed. Furthermore, a sample asteroid volatile mining architecture based on small CubeSat-class spacecraft is presented. It is concluded that key technological drivers for asteroid mining missions are throughput rate, number of spacecraft per mission, and the rate in which successive missions are conducted.

physics.space-ph↗

arXiv2018

Exploring Potential Environmental Benefits of Asteroid Mining

Asteroid mining has been proposed as an approach to complement Earth-based supplies of rare earth metals and supplying resources in space, such as water. Existing research on asteroid mining has mainly looked into its economic viability, technological feasibility, cartography of asteroids, and legal aspects. More recently, potential environmental benefits for asteroid mining have been considered. However, no quantitative estimate of these benefits has been given. This paper attempts to determine if and under which conditions asteroid mining would have environmental benefits, compared to either Earth-based mining or launching equipment and resources into space. We focus on two cases: Water supply to cis-lunar orbit and platinum mining. First, we conduct a state-of-the-art of current environmental life cycle assessment for the space domain and platinum mining. Second, a first order environmental life cycle assessment is conducted, including goal and scope definition, inventory analysis, and impact assessment. We compare water supply to cis-lunar orbit with and without asteroid mining and go on to compare terrestrial with space-based platinum mining. The results indicate that asteroid water mining would have environmental benefits, as soon as the amount of water supplied via mining is larger than the mass of the spacecraft used for mining. For platinum mining, we find that by comparing the operations phase of terrestrial and space mining, space mining would have a lower environmental impact, if the spacecraft is able to return between 0.3 to 7% of its mass in platinum to Earth, assuming 100% primary platinum or 100% secondary platinum, respectively. For future work, we propose a more detailed analysis, based on a more precise inventory and a larger system boundary, including the production of the launcher and spacecraft.

physics.space-ph↗

arXiv2017

The Andromeda Study: A Femto-Spacecraft Mission to Alpha Centauri

This paper discusses the physics, engineering and mission architecture relating to a gram-sized interstellar probe propelled by a laser beam. The objectives are to design a fly-by mission to Alpha Centauri with a total mission duration of 50 years travelling at a cruise speed of 0.1c. Furthermore, optical data from the target star system is to be obtained and sent back to the Solar system. The main challenges of such a mission are presented and possible solutions proposed. The results show that by extrapolating from currently existing technology, such a mission would be feasible. The total mass of the proposed spacecraft is 23g and the space-based laser infrastructure has a beam power output of 15GW. Rurther exploration of the laser - spacecraft tradespace and associated technologies are necessary.

astro-ph.IM↗

arXiv2016

Artificial Intelligence Probes for Interstellar Exploration and Colonization

A recurring topic in interstellar exploration and the search for extraterrestrial intelligence (SETI) is the role of artificial intelligence. More precisely, these are programs or devices that are capable of performing cognitive tasks that have been previously associated with humans such as image recognition, reasoning, decision-making etc. Such systems are likely to play an important role in future deep space missions, notably interstellar exploration, where the spacecraft needs to act autonomously. This article explores the drivers for an interstellar mission with a computation-heavy payload and provides an outline of a spacecraft and mission architecture that supports such a payload. Based on existing technologies and extrapolations of current trends, it is shown that AI spacecraft development and operation will be constrained and driven by three aspects: power requirements for the payload, power generation capabilities, and heat rejection capabilities. A likely mission architecture for such a probe is to get into an orbit close to the star in order to generate maximum power for computational activities, and then to prepare for further exploration activities. Given current levels of increase in computational power, such a payload with a similar computational power as the human brain would have a mass of hundreds to dozens of tons in a 2050 - 2060 timeframe.

physics.pop-ph↗

arXiv2016

Combining Magnetic and Electric Sails for Interstellar Deceleration

The main benefit of an interstellar mission is to carry out in-situ measurements within a target star system. To allow for extended in-situ measurements, the spacecraft needs to be decelerated. One of the currently most promising technologies for deceleration is the magnetic sail which uses the deflection of interstellar matter via a magnetic field to decelerate the spacecraft. However, while the magnetic sail is very efficient at high velocities, its performance decreases with lower speeds. This leads to deceleration durations of several decades depending on the spacecraft mass. Within the context of Project Dragonfly, initiated by the Initiative of Interstellar Studies (i4is), this paper proposes a novel concept for decelerating a spacecraft on an interstellar mission by combining a magnetic sail with an electric sail. Combining the sails compensates for each technologys shortcomings: A magnetic sail is more effective at higher velocities than the electric sail and vice versa. It is demonstrated that using both sails sequentially outperforms using only the magnetic or electric sail for various mission scenarios and velocity ranges, at a constant total spacecraft mass. For example, for decelerating from 5% c, to interplanetary velocities, a spacecraft with both sails needs about 29 years, whereas the electric sail alone would take 35 years and the magnetic sail about 40 years with a total spacecraft mass of 8250 kg. Furthermore, it is assessed how the combined deceleration system affects the optimal overall mission architecture for different spacecraft masses and cruising speeds. Future work would investigate how operating both systems in parallel instead of sequentially would affect its performance. Moreover, uncertainties in the density of interstellar matter and sail properties need to be explored.

physics.space-ph↗