Asteroid Impactor, Comet Impactor, NEO Threat

The Direct Fusion Drive (DFD) is a nuclear fusion engine that produces both thrust and electric power. It employs a field reversed configuration with an odd-parity rotating magnetic field heating system to heat the plasma to fusion temperatures. The engine uses deuterium and helium-3 as fuel and additional deuterium that is heated in the scrape-off layer for thrust augmentation. In this way variable exhaust velocity and thrust is obtained.

It could be argued that in the coming years, as humans venture further into space, a crewed
mission to Mars is inevitable. If this is the case, current propulsion technology is simply
unacceptable for this application, with the most recent mission, the Mars rover Perseverance,
taking 204 days to reach its target in Jezero Crater (NASA, 2020).
The Perseverance mission utilised chemical thrusters, which mix a fuel with an oxidiser to
cause them to combust, producing thrust (NASA, 2020). While this thruster type is capable of
transporting uncrewed missions to the red planet safely, the long transfer times will cause
prolonged exposure to the harmful radiation environment of space, thus, rendering chemical
propulsion unacceptable for crewed Mars missions (Hall, 2018).
The most readily available technology to combat this issue is nuclear propulsion, which has
been predicted to be capable of producing up to 8 times the specific impulse of chemical
propulsion (Oleson, 2022). This paper will compare the different types, history, and features
both of nuclear thermal and nuclear electric propulsion, in an effort to single out one as the best
alternative to land a human on Mars.

Near the Tunguska River in Siberian on 30 June 1908 occurred the explosion in/over the central vent of a paleovolcano, which was associated with a mantle plume. The probability of such an exact hit in the volcanic target for comets/asteroids is close to zero. As a result of hundreds of expeditions to the disaster area, no craters or traces of cosmic substance corresponding to the explosion energy were found. Supporters of comet/asteroid hypotheses concluded that according to barograms and the fall of forest trees at the epicenter, the explosion over the Tunguska paleovolcano could have occurred 5-7 km above the surface. A fragile comet would not penetrate the Earth's atmosphere to such a depth, and an asteroid, in turn, would leave a 2-cm layer of own fragments on the ground [1]. I show that the reason for the 1908 Tunguska event was the joint activity of the Sun and the Moon, starting in the summer of 1907, and especially reinforced from 27 to 30 June 1908, including the time of the solar eclipse on 28 June 1908. The result was a tectonic earthquake of the entire East Siberian platform. This is confirmed, among other things, by registrations by Prof. Weber at the Kiel Observatory of magnetic pulsations from the Tunguska epicenter on 27-30 June 1908. Immersion of stones, i.e. the rise of the surface observed in Tasmania from the beginning of June 1908 and which ceased immediately after the explosion at Tunguska on the morning of 30 June, I attribute to the pressure of underground fluids/gases of the recently discovered Cosgrove's volcanoes in Tasmania. Comets or asteroids could not have caused the surface's uplift in Tasmania. Hence, the hypothesis of an explosion of a cosmic body during the 1908 Tunguska event can be excluded. The boundaries of the observed optical anomalies over Eurasia in the 1908 summer were connected and corresponded to the seismic Perm anomaly, which is located atop the Earth's outer core (LLSVPs Anomaly).

Based on the chemical properties (isotopic ratios from the fossil sea water sediments and the continents), it is possible to divide the Earth’s systems into the basic opposition between the terrigenous and oceanic components. The water/ice environment is considered as a sufficient carrier of panspermia in space due to the characteristic (protecting) properties of water, including UV absorption and superconductivity. Recent observations of L. I. Cleeves show that the oceanic ratio
of D/H represents a dilution and heterogeneous origin of the water on Earth, which perhaps comprises the comets, asteroids, and even the dwarf snow-ball planets or their fragments from the interstellar medium during the formation of the solar protoplanetary disc. Interesting insight was brought by the probe Wild-2 investigating the composition of the comet Temple-1, showing a wide spectrum of minerals, among which water ice is dominant and calcium carbonates were detected. This composition shows which kind of the bodies also showered the mantle of Earth during the Late Heavy Bombardment 4.1–3.8 Ga ago. On a molecular base, the Murchison meteorite with 92 amino acids and meteorite Acfer 086 with protein hemolithin represent good examples of this ancient molecular enrichment. The second part of the chapter deals with a possibility of lithopanspermia, i.e., the idea that micro-organisms can be distributed throughout the planetary system via fragments of rock/ice ejected during a meteoric impact event. Traces of these relationships in case of Earth-Moon system represent granite and also a specimen of breccia collected on the lunar surface by Apollo 14 and 15 crews. The Chandreyaan-1 probe confirmed the evidence of the water on both poles of the Moon and the origin of this water is questioned. Similarly, the question of a possible
ancient Venus-Mercury system (Van Flandern’s and Harrison’s hypothesis), including an alternative explanation for the origin of the water ices in the case of the smaller body.

CAIs Ca_2Al_2O_5 and CaAl_2O_4 add to SiC and (Ti,V,Fe)C pure crystal inclusions in an iron silicide (xifengite, gupeiite, hapkeite) matrix constituting metallic particles from the subsoil in the Alpine Foreland. A cosmic origin is suggested.

Introduction: In the context of the investigation of the Holocene Chiemgau meteorite impact event [18] geological observations have repeatedly been made that suggest a tsunami as a result of the impact of a meteoroid into Lake Chiemsee evidenced by a doublet crater at the bottom of the lake (Fig. 1). Unusual rock debris that fishermen brought up from the lake bed and geologic-archeological excavations around the lake uncovering documents of a young catastrophic event [9-12] also attracted attention. Tsunami deposits are known from earlier geologic periods, and a tsunami to have occurred in a lake (Lake Lucerne, Switzerland) has been discussed [13]. Tsunamis as a consequence of major meteorite impacts into the sea have also been the subject of advanced research [e.g., 14]. Here, I report on a recently discovered outcrop in a gravel pit about 2.5 km off the shore of Lake Chiemsee and on additional compelling geologic evidence of a giant tsunami.

Introduction: The asteroid impact near the Russian city of Chelyabinsk in 2013 was the largest airburst on Earth since the 1908 Tunguska event. Meanwhile, there are scientists who consider airburst as much more dangerous for mankind than direct projectile impacts to form meteorite craters [1]. In the geological past impact cratering accompanied by giant airbursts must have hit Earth periodically, whereby the term cratering refers to the fact that projectiles exploding in the atmosphere may leave their traces also on the ground to form shallow craters. Here we report on effects of a suspected large airburst event, the traces of which are documented by small craters, shock effects, an extended superficial melt rock sheet and significant evidence from GPR investigations.

STRUCTURES: COMPARATIVE INSIGHTS INTO PROMINENT SEDIMENTARY CARBONATE TARGETS. A..Ure, R. Westaway, D.R. Bridgland, F. Claudin, K. Ernstson, School of Environmental, Earth and Ecosystem Science, The Open University, UK; alijoure@hotmail.com. School of Engineering, University of Glasgow, UK; robert.westaway@gla.ac.uk. Department of Geography, Durham University, UK; d.r.bridgland@dur.ac.uk. Llinars del Vallès. Barcelona-08450, Spain; fclaudin@xtec.cat. Faculty of Philosophy 1, University of Würzburg, Germany; kernstson@ernstson.de

Introduction. The Gagarin ring structure has been described as a proposed meteorite crater in 1975 [1]. The assumption was based on morphological details of the structure and geophysical data. Here we report new data which support the possible impact origin of the structure. Description of the structure. The Gagarin ring structure is located 20 km north-west of the town of Gagarin (former Gzhatsk), the Smolensk district. It is centered at 5541’55”N and 3340’1”E. The structure is well recognizable in satellite images (Fig. 1) due to different vegetation types on boggy and dry areas. The inner part of the structure is partly a cornfield. The structure morphology consists of two concentric annular depressions with approximate diameters of 800 and 1400 m. The central part of the structure is 2 meters higher than the depressions and seems to be slightly convex in shape. There are no natural outcrops within the structure and in its vicinity. The structure occurs within the western margin ...

1. Introduction ………………………………………...........................…….…… 1
2. Background ………………………………………………............................…. 2
3. Approach to Clement Conditions on the Earliest Earth ……... 3
4. Ground Zero on the Early Earth ………………………..................….. 4
5. Zirkons and the Earliest Continents ………………………............…. 5
6. World’s Oldest Rocks Locality near Hudson Bay ………….....… 6
7. Advent of Photosynthesis ……………………………….................……. 6
8. Palaeontology of the Earth’s Mantle …………………............……… 8
9. Challenges and Future Research Directions ………......…………. 9
10. Glossary ……………………………………………………...........................… 10

The ̈AIDA ̈ cooperation was initiated in 2011 between ESA, DLR and Observatoire Côte d ́Azur (OCA) on one side and NASA and John Hopkins University Applied Physics Laboratory (JHU/APL) on the other, to assess concepts of mutual interest, with an initial focus on Planetary Defense. The US part, Double Asteroid Redirection Test (DART) would impact a high-velocity projectile into the smaller asteroid of the target binary system 65803 Didymos on October 2022 with the purpose of modifying the relative orbit. The mission goal for ESA’s Asteroid Impact Mission (AIM) study is to characterise the components of a binary asteroid, especially from the dynamical point of view. The mission concept focuses on the monitoring aspects i.e., the capability to determine, in-situ, the key physical properties of a binary asteroid playing a role in the system’s dynamic behaviour. For this purpose, even if not a must, choosing a target whose dynamics have already been well characterised from the ground (e....

EVALUATING ALTERNATIVE CAUSES OF FORMATION IN NON-VOLCANIC SETTINGS ON EARTH AND MARS. J. Plado, A. Jõeleht, A. Losiak, M. Szyszka, J. Ormö, H. Alexanderson, T. Johnsen, C. Alwmark, E. M. Wild, P. Steier, C. Belcher, A.M. Jazwa. Dept. of Geology, Uni. Tartu, Estonia (juri.plado@ut.ee), Institute of Geological Sciences, PAS, Poland; wildFIRE Lab, Uni. Exeter, Dept. of Physical Geography, Stockholm Uni., Sweden, Dept. of Geology, Lund Uni., Sweden, VERA Laboratory, Faculty of Physics—Isotope Physics, Uni. Vienna, Austria.

We argue that it is essential for the fusion energy program to identify an imagination-capturing critical mission by developing a unique product which could command the marketplace. We lay out the logic that this product is a fusion rocket engine, to enable a rapid response capable of deflecting an incoming comet, to prevent its impact on the planet Earth, in defense of our population, infrastructure, and civilization. As a side benefit, deep space solar system exploration, with greater speed and orders-of-magnitude greater payload mass would also be possible.

Introduction: The Ramgarh structure defines a circular shaped topographic high, amidst the vast soil covered plains of the NeoProterozoic Vindhyan Supergroup, near Ramgarh village, Baran district, Rajasthan. It falls between latitudes 25°19′00′′ N and 25°21′00′′ N and longitudes 76°36′20′′ E and 76°38′50′′ E in Survey of India (SOI) toposheet no. 54C/11. It is characterized by peripheral circular ridges, a central depression, with a level difference of 250 m (approx), having a diameter of ~ 3.2 km. Field and laboratory investigations carried out so far by various workers suggest the ring structure at Ramgarh could have been formed by various geological processes. However, more conclusive evidences in favour of an extra-terrestrial or meteoritic impact for its formation have been proposed by [1, 2, 3, 4, 5, 6, 7, 8]. Though a few researcher suggested more detailed analytical studies for identification of shock metamorphism [9]. Methodology: Raman spectra were accquired by using Renis...

Planetary Defense is a complex problem, not well understood by policy makers and the general public. The recent Chelyabinsk incident in Russia created temporary international attention but has failed to effectively stimulate public action. The lack of long-term attention to cosmic hazards has resulted in limited funding to defend our planet. Hence, it is hard to realistically address this challenge and achieve the high test and operational readiness needed for an effective Planetary Defense strategy. To address this problem, we have created a set of recommendations for the development of a Planetary Defense Program, for the purpose of contributing to the protection of Earth from asteroids and comets. The SSP15 READI Project focused on threats for which there is only a short-term warning, specifically a warning of two years or less from detection of the object to impact. We have provided recommendations in five areas of Planetary Defense including detection and tracking, deflection t...