scholarly journals QUARC: Quantum Research Cubesat—A Constellation for Quantum Communication

Cryptography ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 7 ◽  
Author(s):  
Luca Mazzarella ◽  
Christopher Lowe ◽  
David Lowndes ◽  
Siddarth Koduru Joshi ◽  
Steve Greenland ◽  
...  
Keyword(s):  
Secure Communication ◽  
Meteorological Data ◽  
Low Cost ◽  
Key Distribution ◽  
Low Earth Orbit ◽  
Long Distance ◽  
Small Satellites ◽  
Orbital Parameters ◽  
The Uk ◽  
Atmospheric Channel

Quantum key distribution (QKD) offers future proof security based on fundamental laws of physics. Long-distance QKD spanning regions such as the United Kingdom (UK) may employ a constellation of satellites. Small satellites, CubeSats in particular, in low Earth orbit are a relatively low-cost alternative to traditional, large platforms. They allow the deployment of a large number of spacecrafts, ensuring greater coverage and mitigating some of the risk associated with availability due to cloud cover. We present our mission analysis showing how a constellation comprising 15 low-cost 6U CubeSats can be used to form a secure communication backbone for ground-based and metropolitan networks across the UK. We have estimated the monthly key rates at 43 sites across the UK, incorporating local meteorological data, atmospheric channel modelling and orbital parameters. We have optimized the constellation topology for rapid revisit and thus low-latency key distribution.

scholarly journals Guidance Stabilization of Satellites Using the Geomagnetic Field

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Francisco Miranda
Keyword(s):  
Geomagnetic Field ◽  
Technological Development ◽  
Low Cost ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Small Satellites ◽  
Attitude Stabilization ◽  
Short Period ◽  
Low Earth Orbit Satellite ◽  
Games Theory

In the last years the small satellites have played an important role in the technological development. The attractive short period of design and low cost of them and the capacity to solve problems that are usually considered as problems to big and expensive spacecrafts lead us to study the control problem of these satellites. Active three-axis magnetic attitude stabilization of a low Earth orbit satellite is considered in this work. The control is created by interaction between the magnetic moment generated by magnetorquers mounted on the satellite body and the geomagnetic field. This problem is quite complex and difficult to solve. To overcome this difficulty guidance control is considered, where we use ε-strategies introduced by Pontryagin in the frame of differential games theory. Qualitative analysis and results of numerical simulation are presented.

scholarly journals DECOY STATE QUANTUM KEY DISTRIBUTION

2005 ◽  
Vol 03 (supp01) ◽  
pp. 143-143 ◽  
Author(s):  
HOI-KWONG LO
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Generation Rate ◽  
Key Generation ◽  
Long Distance ◽  
Decoy State ◽  
Bb84 Protocol ◽  
High Loss ◽  
Statistical Fluctuations

Quantum key distribution (QKD) allows two parties to communicate in absolute security based on the fundamental laws of physics. Up till now, it is widely believed that unconditionally secure QKD based on standard Bennett-Brassard (BB84) protocol is limited in both key generation rate and distance because of imperfect devices. Here, we solve these two problems directly by presenting new protocols that are feasible with only current technology. Surprisingly, our new protocols can make fiber-based QKD unconditionally secure at distances over 100km (for some experiments, such as GYS) and increase the key generation rate from O(η2) in prior art to O(η) where η is the overall transmittance. Our method is to develop the decoy state idea (first proposed by W.-Y. Hwang in "Quantum Key Distribution with High Loss: Toward Global Secure Communication", Phys. Rev. Lett. 91, 057901 (2003)) and consider simple extensions of the BB84 protocol. This part of work is published in "Decoy State Quantum Key Distribution", . We present a general theory of the decoy state protocol and propose a decoy method based on only one signal state and two decoy states. We perform optimization on the choice of intensities of the signal state and the two decoy states. Our result shows that a decoy state protocol with only two types of decoy states—a vacuum and a weak decoy state—asymptotically approaches the theoretical limit of the most general type of decoy state protocols (with an infinite number of decoy states). We also present a one-decoy-state protocol as a special case of Vacuum+Weak decoy method. Moreover, we provide estimations on the effects of statistical fluctuations and suggest that, even for long distance (larger than 100km) QKD, our two-decoy-state protocol can be implemented with only a few hours of experimental data. In conclusion, decoy state quantum key distribution is highly practical. This part of work is published in "Practical Decoy State for Quantum Key Distribution", . We also have done the first experimental demonstration of decoy state quantum key distribution, over 15km of Telecom fibers. This part of work is published in "Experimental Decoy State Quantum Key Distribution Over 15km", .

scholarly journals LATLAUNCH AIR-LAUNCH SYSTEM FOR LOW-COST LAUNCHING OF SMALL SATELLITES INTO LOW EARTH ORBIT

Aviation ◽  
2021 ◽  
Vol 25 (2) ◽  
pp. 73-78
Author(s):  
Aleksandrs Urbahs ◽  
Sergey Kravchenko ◽  
Margarita Urbaha ◽  
Kristine Carjova ◽  
Natalja Panova ◽  
...  
Keyword(s):  
Low Cost ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Competitive Advantages ◽  
Characteristic Velocity ◽  
Small Satellites ◽  
Aerial Platform

The paper presents the air-launch system enabling the delivery of small satellites into low Earth orbit. One of the most important advantages of the concept is its cost. Generally, the paper proves that launching a carrier from an aerial platform (a movable launch pad) provides the whole range of competitive advantages. In particular, the total losses during the launch from an aerial platform will reduce by 20–35%, and the characteristic velocity of the maneuver will reduce by 4–7%.

scholarly journals Space Biology Research and Biosensor Technologies: Past, Present, and Future

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 38
Author(s):  
Ada Kanapskyte ◽  
Elizabeth M. Hawkins ◽  
Lauren C. Liddell ◽  
Shilpa R. Bhardwaj ◽  
Diana Gentry ◽  
...  
Keyword(s):  
Low Cost ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Model Organisms ◽  
Deep Space ◽  
Space Biology ◽  
Small Satellites ◽  
Biological Phenomena ◽  
Space Environments ◽  
The 1960S

In light of future missions beyond low Earth orbit (LEO) and the potential establishment of bases on the Moon and Mars, the effects of the deep space environment on biology need to be examined in order to develop protective countermeasures. Although many biological experiments have been performed in space since the 1960s, most have occurred in LEO and for only short periods of time. These LEO missions have studied many biological phenomena in a variety of model organisms, and have utilized a broad range of technologies. However, given the constraints of the deep space environment, upcoming deep space biological missions will be largely limited to microbial organisms and plant seeds using miniaturized technologies. Small satellites such as CubeSats are capable of querying relevant space environments using novel, miniaturized instruments and biosensors. CubeSats also provide a low-cost alternative to larger, more complex missions, and require minimal crew support, if any. Several have been deployed in LEO, but the next iterations of biological CubeSats will travel beyond LEO. They will utilize biosensors that can better elucidate the effects of the space environment on biology, allowing humanity to return safely to deep space, venturing farther than ever before.

scholarly journals Design, Implementation, and Operation of a Small Satellite Mission to Explore the Space Weather Effects in LEO

Aerospace ◽  
2019 ◽  
Vol 6 (10) ◽  
pp. 108 ◽  
Author(s):  
Isai Fajardo ◽  
Aleksander Lidtke ◽  
Sidi Bendoukha ◽  
Jesus Gonzalez-Llorente ◽  
Rafael Rodríguez ◽  
...  
Keyword(s):  
Space Weather ◽  
Low Cost ◽  
Low Earth Orbit ◽  
Space Environment ◽  
Small Satellite ◽  
Satellite Mission ◽  
Particle Detectors ◽  
Small Satellites ◽  
Environment Effects ◽  
Institute Of Technology

Ten-Koh is a 23.5 kg, low-cost satellite developed to conduct space environment effects research in low-Earth orbit (LEO). Ten-Koh was developed primarily by students of the Kyushu Institute of Technology (Kyutech) and launched on 29 October 2018 on-board HII-A rocket F40, as a piggyback payload of JAXA’s Greenhouse gas Observing Satellite (GOSAT-2). The satellite carries a double Langmuir probe, CMOS-based particle detectors and a Liulin spectrometer as main payloads. This paper reviews the design of the mission, specifies the exact hardware used, and outlines the implementation and operation phases of the project. This work is intended as a reference that other aspiring satellite developers may use to increase their chances of success. Such a reference is expected to be particularly useful to other university teams, which will likely face the same challenges as the Ten-Koh team at Kyutech. Various on-orbit failures of the satellite are also discussed here in order to help avoid them in future small spacecraft. Applicability of small satellites to conduct space-weather research is also illustrated on the Ten-Koh example, which carried out simultaneous measurements with JAXA’s ARASE satellite.

scholarly journals Unidimensional Continuous-Variable Quantum Key Distribution with Untrusted Detection under Realistic Conditions

Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1100 ◽  
Author(s):  
Luyu Huang ◽  
Yichen Zhang ◽  
Ziyang Chen ◽  
Song Yu
Keyword(s):  
Quantum Key Distribution ◽  
Coherent States ◽  
Secure Communication ◽  
Key Distribution ◽  
Continuous Variable ◽  
Third Party ◽  
Modulation Method ◽  
Secret Key ◽  
Long Distance ◽  
Quantum Key Distribution Protocol

A unidimensional continuous-variable quantum key distribution protocol with untrusted detection is proposed, where the two legitimate partners send unidimensional modulated or Gaussian-modulated coherent states to an untrusted third party, i.e., Charlie, to realize the measurement. Compared with the Gaussian-modulated coherent-state protocols, the unidimensional modulated protocols take the advantage of easy modulation, low cost, and only a small number of random numbers required. Security analysis shows that the proposed protocol cannot just defend all detectors side channels, but also achieve great performance under certain conditions. Specifically, three cases are discussed in detail, including using unidimensional modulated coherent states in Alice’s side, in Bob’s side, and in both sides under realistic conditions, respectively. Under the three conditions, we derive the expressions of the secret key rate and give the optimal gain parameters. It is found that the optimal performance of the protocol is achieved by using unidimensional modulated coherent states in both Alice’s and Bob’s side. The resulting protocol shows the potential for long-distance secure communication using the unidimensional quantum key distribution protocol with simple modulation method and untrusted detection under realistic conditions.

scholarly journals Electrojet estimates from mesospheric magnetic field measurements

2020 ◽  
Author(s):  
Karl Laundal ◽  
Jesper Gjerloev ◽  
Sam Yee ◽  
Slava Merkin ◽  
Heikki Vanhamäki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Low Earth Orbit ◽  
Measurement Technology ◽  
Earth Orbit ◽  
Long Distance ◽  
Small Satellites ◽  
Spatiotemporal Characteristics ◽  
Magnetic Field Measurements ◽  
The Magnetic Field

<p>The auroral electrojet is traditionally measured remotely with magnetometers on ground or in low Earth orbit. The long distance, more than 100 km, means that smaller scale sizes are not detected. Because of this, the spatiotemporal characteristics of the electrojet are not known. Recent advances in measurement technology give hope of remote detections of the magnetic field in the mesosphere, very close to the electrojet. We present a prediction of the magnitude of these disturbances, inferred from the spatiotemporal characteristics of magnetic field-aligned currents. We also discuss how a constellation of small satellites carrying the Microwave Electrojet Magnetogram (MEM) instrument (Yee et al., 2020), could be used to essentially image the equivalent current at unprecedented spatial resolution. </p>

scholarly journals Analysis of Solar Energy Resources in Southern Poland for Photovoltaic Applications / Analiza Struktury Zasobów Energii Słonecznej Obszaru Polski Południowej Do Zastosowań Fotowoltaicznych

2013 ◽  
Vol 20 (1) ◽  
pp. 177-198 ◽  
Author(s):  
Tadeusz Rodziewicz ◽  
Janusz Teneta ◽  
Aleksander Zaremba ◽  
Maria Wacławek
Keyword(s):  
Solar Energy ◽  
Meteorological Data ◽  
Low Cost ◽  
Spectral Characteristics ◽  
Solar Spectrum ◽  
Energy Resources ◽  
Photovoltaic Module ◽  
The European Union ◽  
Southern Poland ◽  
The Uk

Abstract The article presents an analysis of the resources and the structure of the solar energy in the area of Southern Poland on the basis of complete meteorological data from the AGH University of Science and Technology in Krakow in 2009. An analysis attempt of its use for photovoltaic conversion using different modules with different spectral characteristics of absorbers was made. These latest methods for characterizing the structure of solar energy resources such as: distributions throughout the year: sky clearness or cloudiness indexes, the average values of photon energy (APE) and the contents of the useful fraction (UF) of the solar spectrum, are not yet widely known and used as in Poland and in other EU countries, despite the fact that most accurately determine the spectral matching factor for the chosen photovoltaic module. Due to the need for a very expensive measuring equipment, are used only by a few laboratories in the European Union, such as CREST (Centre for Renewable Energy Systems Technology) in the UK. The article presents - developed and used in the Opole University - a new low-cost method for determining of the spectrum with the use of above-mentioned indexes, including APE and UF, without buying an expensive spectroradiometer, which gives comparable results.

scholarly journals Rain Erosion Maps for Wind Turbines Based on Geographical Locations: A Case Study in Ireland and Britain

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
K. Pugh ◽  
M. M. Stack
Keyword(s):  
Wind Turbine ◽  
Western Europe ◽  
Meteorological Data ◽  
Turbine Blades ◽  
Weather Conditions ◽  
Annual Rainfall ◽  
Wind Turbine Blades ◽  
Weather Patterns ◽  
The Uk

AbstractErosion rates of wind turbine blades are not constant, and they depend on many external factors including meteorological differences relating to global weather patterns. In order to track the degradation of the turbine blades, it is important to analyse the distribution and change in weather conditions across the country. This case study addresses rainfall in Western Europe using the UK and Ireland data to create a relationship between the erosion rate of wind turbine blades and rainfall for both countries. In order to match the appropriate erosion data to the meteorological data, 2 months of the annual rainfall were chosen, and the differences were analysed. The month of highest rain, January and month of least rain, May were selected for the study. The two variables were then combined with other data including hailstorm events and locations of wind turbine farms to create a general overview of erosion with relation to wind turbine blades.

scholarly journals The BabySaver: Design of a New Device for Neonatal Resuscitation at Birth with Intact Placental Circulation

Children ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 526
Author(s):  
James Ditai ◽  
Aisling Barry ◽  
Kathy Burgoine ◽  
Anthony K. Mbonye ◽  
Julius N. Wandabwa ◽  
...  
Keyword(s):  
Low Cost ◽  
Neonatal Resuscitation ◽  
Sub Saharan Africa ◽  
Skilled Birth Attendants ◽  
New Device ◽  
Birth Attendants ◽  
Premature Babies ◽  
Sub Saharan ◽  
The Uk ◽  
The University

The initial bedside care of premature babies with an intact cord has been shown to reduce mortality; there is evidence that resuscitation of term babies with an intact cord may also improve outcomes. This process has been facilitated by the development of bedside resuscitation surfaces. These new devices are unaffordable, however, in most of sub-Saharan Africa, where 42% of the world’s 2.4 million annual newborn deaths occur. This paper describes the rationale and design of BabySaver, an innovative low-cost mobile resuscitation unit, which was developed iteratively over five years in a collaboration between the Sanyu Africa Research Institute (SAfRI) in Uganda and the University of Liverpool in the UK. The final BabySaver design comprises two compartments; a tray to provide a firm resuscitation surface, and a base to store resuscitation equipment. The design was formed while considering contextual factors, using the views of individual women from the community served by the local hospitals, medical staff, and skilled birth attendants in both Uganda and the UK.

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