Space environment management: Framing the objective and setting priorities for controlling orbital debris risk

AbstractIn the last decade, self-healing materials have become extremely appealing for the field of space applications, due to their technological evolution and the consequent possibility of designing space systems and structures able to repair autonomously after damage arising from impacts with micrometeoroids and orbital debris, from accidental contact with sharp objects, from structural fatigue or simply due to material aging. The integration of these novel materials in the design of spacecraft structures would result in increased reliability and safety leading to longer operational life and missions. Such concepts will bring a decisive boost enabling new mission scenario for the establishment of new orbital stations, settlement on the Moon and human exploration of Mars.The proposed review aims at presenting the newest and most promising self-healing materials and associated technologies for space application, along with the issues related to their current technological limitations in combination with the effect of the space environment. An introductory part about the outlooks and challenges of space exploration and the self-healing concept is followed by a brief description of the space environment and its possible effects on the performance of materials. Self-healing materials are then analysed in detail, moving from the general intrinsic and extrinsic categories down to the specific mechanisms.

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Extravehicular Activity Micrometeoroid and Orbital Debris Risk Assessment Methodology

2019 15th Hypervelocity Impact Symposium ◽

10.1115/hvis2019-058 ◽

2019 ◽

Author(s):

Kevin D. Hoffman ◽

James L. Hyde ◽

Eric L. Christiansen ◽

Dana M. Lear

Keyword(s):

Risk Assessment ◽

Orbital Debris ◽

Space Environment ◽

Assessment Methodology ◽

Loss Of Life ◽

Extravehicular Activity ◽

Mobility Unit ◽

Risk Assessment Methodology ◽

Soft Goods

Abstract A well-known hazard associated with exposure to the space environment is the risk of vehicle failure due to an impact from a micrometeoroid and orbital debris (MMOD) particle. Among the vehicles of importance to NASA is the extravehicular mobility unit (EMU) “spacesuit” used while performing a US extravehicular activity (EVA). An EMU impact is of great concern as a large leak could prevent an astronaut from safely reaching the airlock in time resulting in a loss of life. For this reason, a risk assessment is provided to the EVA office at the Johnson Space Center (JSC) prior to certification of readiness for each US EVA. This paper will detail the methodology for an ISS EVA risk assessment. The soft goods regions (multilayer fabric over a pressurized bladder) are the highest contributors of risk for an ISS EVA. The gloves, due to reduced fabric layers to allow for improved dexterity, carry the highest risk per area. ISS EVA risk can be reduced by minimizing the exposure of the front of the suit and gloves to the orbital debris flux.

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Tuning of NASA Standard Breakup Model for Fragmentation Events Modelling

Aerospace ◽

10.3390/aerospace8070185 ◽

2021 ◽

Vol 8 (7) ◽

pp. 185

Author(s):

Nicola Cimmino ◽

Giorgio Isoletta ◽

Roberto Opromolla ◽

Giancarmine Fasano ◽

Aniello Basile ◽

...

Keyword(s):

Space Debris ◽

Small Mass ◽

Orbital Debris ◽

Space Environment ◽

Iterative Approach ◽

Continuous Growth ◽

Collision Event ◽

Line Elements ◽

Breakup Model ◽

Orbital Data

The continuous growth of space debris motivates the development and the improvement of tools that support the monitoring of a more and more congested space environment. Satellite breakup models play a key role to predict and analyze orbital debris evolution, and the NASA Standard Breakup Model represents a widely used reference, with current activities relevant to its evolution and improvements especially towards fragmentation of small mass spacecraft. From an operational perspective, an important point for fragmentation modelling concerns the tuning of the breakup model to achieve consistency with orbital data of observed fragments. In this framework, this paper proposes an iterative approach to estimate the model inputs, and in particular, the parents’ masses involved in a collision event. The iterative logic exploits the knowledge of Two Line Elements (TLE) of the fragments at some time after the event to adjust the input parameters of the breakup model with the objective of obtaining the same number of real fragments within a certain tolerance. Atmospheric re-entry is accounted for. As a result, the breakup model outputs a set of fragments whose statistical distribution, in terms of number and size, is consistent with the catalogued ones. The iterative approach is demonstrated for two different scenarios (i.e., catastrophic collision and non-catastrophic collision) using numerical simulations. Then, it is also applied to a real collision event.

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Quantitative surface damage studies by H.R.E.M.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015513x ◽

1989 ◽

Vol 47 ◽

pp. 632-633

Author(s):

S. R. Singh ◽

H. J. Fan ◽

L. D. Marks

Keyword(s):

Solar Wind ◽

Quantitative Analysis ◽

Surface Science ◽

Surface Damage ◽

Space Environment ◽

Oxygen Desorption ◽

The Past ◽

Diffusion Controlled ◽

Original Observation ◽

Substantial Interest

Since the original observation that the surfaces of materials undergo radiation damage in the electron microscope similar to that observed by more conventional surface science techniques there has been substantial interest in understanding these phenomena in more detail; for a review see. For instance, surface damage in a microscope mimics damage in the space environment due to the solar wind and electron beam lithographic operations.However, purely qualitative experiments that have been done in the past are inadequate. In addition, many experiments performed in conventional microscopes may be inaccurate. What is needed is careful quantitative analysis including comparisons of the behavior in UHV versus that in a conventional microscope. In this paper we will present results of quantitative analysis which clearly demonstrate that the phenomena of importance are diffusion controlled; more detailed presentations of the data have been published elsewhere.As an illustration of the results, Figure 1 shows a plot of the shrinkage of a single, roughly spherical particle of WO3 versus time (dose) driven by oxygen desorption from the surface.

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New Director Named for NOAA's Space Environment Center

Space Weather ◽

10.1029/2006sw000255 ◽

2006 ◽

Vol 4 (6) ◽

pp. n/a-n/a

Author(s):

Mohi Kumar

Keyword(s):

Space Environment

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Optimizing genotype-environment-management interactions to ensure silage maize production in the Chinese Maize Belt

Climate Research ◽

10.3354/cr01599 ◽

2020 ◽

Vol 80 (2) ◽

pp. 133-146

Author(s):

L Zhang ◽

Z Zhang ◽

J Cao ◽

Y Luo ◽

Z Li

Keyword(s):

Field Experiments ◽

Weather Conditions ◽

Growth Cycle ◽

High Energy ◽

Risk Level ◽

Energy Yield ◽

Maize Production ◽

Early Date ◽

Environment Management ◽

Silage Maize

Grain maize production exceeds the demand for grain maize in China. Methods for harvesting good-quality silage maize urgently need a theoretical basis and reference data in order to ensure its benefits to farmers. However, research on silage maize is limited, and very few studies have focused on its energetic value and quality. Here, we calibrated the CERES-Maize model for 24 cultivars with 93 field experiments and then performed a long-term (1980-2017) simulation to optimize genotype-environment-management (G-E-M) interactions in the 4 main agroecological zones across China. We found that CERES-Maize could reproduce the growth and development of maize well under various management and weather conditions with a phenology bias of <5 d and biomass relative root mean square error values of <5%. The simulated results showed that sowing long-growth-cycle cultivars approximately 10 d in advance could yield good-quality silage. The optimal sowing dates (from late May to July) and harvest dates (from early October to mid-November) gradually became later from north to south. A high-energy yield was expected when sowing at an early date and/or with late-maturing cultivars. We found that Northeast China and the North China Plain were potential silage maize growing areas, although these areas experienced a medium or even high frost risk. Southwestern maize experienced a low risk level, but the low soil fertility limited the attainable yield. The results of this paper provide information for designing an optimal G×E×M strategy to ensure silage maize production in the Chinese Maize Belt.

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