It is proved that Cp(X,0,1) is pseudocompact if and only if it has a dense cofinally Polish subspace. We also establish that Cp(X,0,1) is pseudocomplete if and only if it is pseudocompact and give a ...consistent example of a locally compact hereditarily separable space which is not cofinally Polish. This paper also features cofinally Baire spaces which form a wider class than cofinally Polish spaces; it is established that every locally pseudocompact space is cofinally Baire as well as every locally Polish space, every scattered space and every P-space. Our results solve several published open questions.
The Comet Interceptor Mission Snodgrass, Colin; Lara, Luisa M.; Agarwal, Jessica ...
Space science reviews,
2024, Volume:
220, Issue:
1
Journal Article
Peer reviewed
Open access
Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first ...time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum
Δ
V capability of
600
ms
−
1
. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.
This paper develops an interdisciplinary space architecture optimization framework to analyze the tradeoff on in-situ resource utilization options, identify technology gaps, evaluate the benefits of ...in-situ resource utilization, and optimize the design of infrastructure for Mars human space exploration scenarios and mission profiles. It performs trade studies from the perspective of space logistics, which takes into account the interplanetary transportation, infrastructure deployment, in-situ resource utilization system operation, and logistics of the produced resources. Our method considers space architecture design and operation from the subsystem level to capture the coupling between in-situ resource utilization technologies and in-space architecture elements for space resource logistics. A case study involving a multi-mission human Mars exploration campaign is performed to evaluate the effectiveness of existing and proposed in-situ resource utilization technology concepts and system designs. The results can provide us with a better understanding of the benefits and costs of different in-situ resource utilization technologies for interplanetary space transportation. A sensitivity analysis is also conducted to understand the impacts of lunar and near-Earth-object's in-situ resource utilization systems on Mars missions. The results of this analysis can help decision-makers determine and optimize the roadmap for in-situ resource utilization technology development.
•Subsystem-level in-situ resource plant design enables technology tradeoff.•Multiple in-space infrastructure sizing, price, and tradeoff models are established.•A Mars exploration case study is conducted with infrastructure design and logistics.
The capital of the Aztec empire, Tenochtitlan, was, in its era, one of the largest cities in the world. Built on an island in the middle of a shallow lake, its population numbered perhaps 150,000, ...with another 350,000 people in the urban network clustered around the lake shores. In 1521, at the height of Tenochtitlan's power, which extended over much of Central Mexico, Hernando Cortés and his followers conquered the city. Cortés boasted to King Charles V of Spain that Tenochtitlan was "destroyed and razed to the ground." But was it?Drawing on period representations of the city in sculptures, texts, and maps, The Death of Aztec Tenochtitlan, the Life of Mexico City builds a convincing case that this global capital remained, through the sixteenth century, very much an Amerindian city. Barbara E. Mundy foregrounds the role the city's indigenous peoples, the Nahua, played in shaping Mexico City through the construction of permanent architecture and engagement in ceremonial actions. She demonstrates that the Aztec ruling elites, who retained power even after the conquest, were instrumental in building and then rebuilding the city. Mundy shows how the Nahua entered into mutually advantageous alliances with the Franciscans to maintain the city's sacred nodes. She also focuses on the practical and symbolic role of the city's extraordinary waterworks—the product of a massive ecological manipulation begun in the fifteenth century—to reveal how the Nahua struggled to maintain control of water resources in early Mexico City.
The Juno Mission Bolton, S. J.; Lunine, J.; Stevenson, D. ...
Space science reviews,
11/2017, Volume:
213, Issue:
1-4
Journal Article
Peer reviewed
Juno is a PI-led mission to Jupiter, the second mission in NASA’s New Frontiers Program. The 3625-kg spacecraft spins at 2 rpm and is powered by three 9-meter-long solar arrays that provide ∼500 ...watts in orbit about Jupiter. Juno carries eight science instruments that perform nine science investigations (radio science utilizes the communications antenna). Juno’s science objectives target Jupiter’s origin, interior, and atmosphere, and include an investigation of Jupiter’s polar magnetosphere and luminous aurora.
Ramsey theory is a fast-growing area of combinatorics with deep connections to other fields of mathematics such as topological dynamics, ergodic theory, mathematical logic, and algebra. The area of ...Ramsey theory dealing with Ramsey-type phenomena in higher dimensions is particularly useful. Introduction to Ramsey Spaces presents in a systematic way a method for building higher-dimensional Ramsey spaces from basic one-dimensional principles. It is the first book-length treatment of this area of Ramsey theory, and emphasizes applications for related and surrounding fields of mathematics, such as set theory, combinatorics, real and functional analysis, and topology. In order to facilitate accessibility, the book gives the method in its axiomatic form with examples that cover many important parts of Ramsey theory both finite and infinite.
With fascinating insights into the management of NASA's Apollo program, this book explains how Mueller single-handedly introduced new administrative approaches that facilitated US president John F. ...Kennedy's goal of landing an astronaut on the moon.
While space is perceived as unitary, experimental evidence indicates that the brain actually contains a modular representation of space, specific cortical regions being involved in the processing of ...extra-personal space, that is the space that is far away from the subject and that cannot be directly acted upon by the body, while other cortical regions process peripersonal space, that is the space that directly surrounds us and which we can act upon. In the present review, we focus on non-human primate research and we review the single cells, areal and cortical functional network mechanisms that are proposed to underlie extrapersonal and peripersonal space representations. Importantly, the current dominant framework for the study of peripersonal space is centered on the key notion that actions and specifically arm and hand-related actions, shape cortical peripersonal space representations. In the present review, we propose to enlarge this framework to include other variables that have the potential to shape peripersonal space representations, namely emotional and social information. In the initial section of the manuscript, we thus first provide an extensive up-to-date review of the low level sensory and oculomotor signals that contribute to the construction of a core cortical far and near space representation, in key parietal, premotor and prefrontal periarcuate cortical regions. We then highlight the key functional properties that are needed to encode peripersonal space and we narrow down our discussion to the specific parietal and periarcuate areas that share these properties: the parieto-premotor peripersonal space network and the parieto-premotor network for grasping. Last, we review evidence for a changing peripersonal space representation. While plastic changes in peripersonal space representation have been described during tool use and their underlying neural bases have been well characterized, the description of dynamical changes in peripersonal space representation as a function of the emotional or social context is quite novel and relies on behavioral human studies. The neural bases of such a dynamic adjustments of peripersonal space coding are yet unknown. We thus review these novel observations and we discuss their putative underlying neural bases.
•Low-level disparity and vergence signals define a core cortical far and near space representation.•Well identified parietal and premotor cortical regions preferentially encode peripersonal space.•Peripersonal boundaries change as a result of alterations in the body schema or in the emotional or social context.•We propose that these changes result from the dynamic modulation of the core cortical far and near space representation.
The texts presented in Proportion Harmonies and Identities (PHI) Time and Space were compiled to establish a multidisciplinary platform for presenting, interacting, and disseminating research. It ...also aims to foster awareness and discussion on Time and Space, focusing on different visions relevant to Architecture, Arts and Humanities, Design and Social Sciences, and its importance and benefits for the sense of identity, both individual and communal. The idea of Time and Space has been a powerful motor for development since the Western Early Modern Age. Its theoretical and practical foundations have become the working tools of scientists, philosophers, and artists, who seek strategies and policies to accelerate the development process in different contexts.
The problem of describing the analytic functions
g
on the unit disc such that the integral operator
T
g
(
f
)
(
z
)
=
∫
0
z
f
(
ζ
)
g
′
(
ζ
)
d
ζ
is bounded (or compact) from a Banach space (or ...complete metric space)
X
of analytic functions to the Hardy space
H
∞
is a tough problem, and remains unsettled in many cases. For analytic functions
g
with non-negative Maclaurin coefficients, we describe the boundedness and compactness of
T
g
acting from a weighted Dirichlet space
D
ω
p
, induced by an upper doubling weight
ω
, to
H
∞
. We also characterize, in terms of neat conditions on
ω
, the upper doubling weights for which
T
g
:
D
ω
p
→
H
∞
is bounded (or compact) only if
g
is constant.
