Altitude Control of Single Axis Solar Sail through a Gimbal

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Thangavel Sanjeeviraja ◽  
R. Santhanakrishnan ◽  
S. Lakshmi ◽  
R. Asokan
Keyword(s):  
Interplanetary Space ◽  
Dynamic Control ◽  
Flight Test ◽  
Solar Sail ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Centre Of Mass ◽  
Centre Of Pressure ◽  
Solar Sailing ◽  
Altitude Control

The purpose of designing a spacecraft Altitude and dynamic control models play an important role in an interplanetary space mission. Particular emphasis is controlling spacecraft Altitude by sail tilting and shifting. In addition, investigate an uncertain balance amongst the centre of pressure and centre of mass on a single axis gimbaled control. Implies a method of Monte Carlo is with standing a significant of solar pressure disturbance torque in deep space mission. A flight test experiment drives in a Low Earth Orbit (LEO), hence, authenticate the source of solar sailing is also suggested. Parameters are incorporating to study and demonstrate the various principals and methods involved in altitude control design and dynamic modeling at LEO. Mitigation of disturbance torques was also examined.

scholarly journals An advance in transfer line chilldown heat transfer of cryogenic propellants in microgravity using microfilm coating for enabling deep space exploration

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
J. N. Chung ◽  
Jun Dong ◽  
Hao Wang ◽  
S. R. Darr ◽  
J. W. Hartwig
Keyword(s):  
Space Exploration ◽  
Fluid Management ◽  
Microgravity Condition ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Deep Space ◽  
Deep Space Exploration ◽  
Quenching Efficiency ◽  
Proper Perspective

AbstractThe extension of human space exploration from a low earth orbit to a high earth orbit, then to Moon, Mars, and possibly asteroids is NASA’s biggest challenge for the new millennium. Integral to this mission is the effective, sufficient, and reliable supply of cryogenic propellant fluids. Therefore, highly energy-efficient thermal-fluid management breakthrough concepts to conserve and minimize the cryogen consumption have become the focus of research and development, especially for the deep space mission to mars. Here we introduce such a concept and demonstrate its feasibility in parabolic flights under a simulated space microgravity condition. We show that by coating the inner surface of a cryogenic propellant transfer pipe with low-thermal conductivity microfilms, the quenching efficiency can be increased up to 176% over that of the traditional bare-surface pipe for the thermal management process of chilling down the transfer pipe. To put this into proper perspective, the much higher efficiency translates into a 65% savings in propellant consumption.

Fluorinated Single Wall Nanotube/Polyethylene Composites for Multifunctional Radiation Protection

2002 ◽  
Vol 740 ◽  
Author(s):  
Merlyn X. Pulikkathara ◽  
Meisha L. Shofner ◽  
Richard T. Wilkins ◽  
Jesus G. Vera ◽  
Enrique V. Barrera ◽  
...  
Keyword(s):  
Radiation Protection ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Proton Radiation ◽  
Freeform Fabrication ◽  
Nanotube Composites ◽  
Total Fluence ◽  
Hydrogen Exposure ◽  
The Stability ◽  
Single Wall Nanotubes

ABSTRACTFluorinated Single Wall Nanotubes (f-SWNTs) have been processed in polyethylene by an incipient wetting technique to achieve a well dispersed nanocomposite for radiation protection. In some cases, samples were further processed using the rapid prototyping method of extrusion freeform fabrication. Composites were exposed to 40 MeV proton radiation with a flux of about 1.7×107 protons/cm2/sec to a total fluence of 3×1010 protons/cm2.This exposure is consistent with a long-term space mission in low earth orbit. The samples were evaluated by means of Raman spectroscopy and thermogravimetric analysis (TGA). These results were compared to the unexposed composite and unfilled polymer samples. This study has focused on the stability of the nanotube composites when exposed to radiation and prior to hydrogen exposure. It was shown that the stability of the functional group is not constant with SWNTs produced by different processes and that radiation exposure is capable of defluorinating SWNTs in polyethylene.

On the Challenges of Anesthesia and Surgery during Interplanetary Spaceflight

2021 ◽  
Author(s):  
Matthieu Komorowski ◽  
Séamus Thierry ◽  
Clément Stark ◽  
Mark Sykes ◽  
Jochen Hinkelbein
Keyword(s):  
Interplanetary Space ◽  
Space Mission ◽  
Environmental Challenges ◽  
Surgical Case ◽  
Near Future

This focused review summarizes the medical, logistical and environmental challenges that would be associated with dealing with a traumatic surgical case during an interplanetary space mission in the near future.

scholarly journals A GA-SA Hybrid Planning Algorithm Combined with Improved Clustering for LEO Observation Satellite Missions

Algorithms ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 231
Author(s):  
Xiangyu Long ◽  
Shufan Wu ◽  
Xiaofeng Wu ◽  
Yixin Huang ◽  
Zhongcheng Mu
Keyword(s):  
Clustering Algorithm ◽  
Simulated Annealing Algorithm ◽  
Space Mission ◽  
Theory Model ◽  
Low Earth Orbit ◽  
Mission Planning ◽  
Experimental Simulation ◽  
Two Phase ◽  
Fitness Value ◽  
Planning Algorithm

This paper presents a space mission planning tool, which was developed for LEO (Low Earth Orbit) observation satellites. The tool is focused on a two-phase planning strategy with clustering preprocessing and mission planning, where an improved clustering algorithm is applied, and a hybrid algorithm that combines the genetic algorithm with the simulated annealing algorithm (GA–SA) is given and discussed. Experimental simulation studies demonstrate that the GA–SA algorithm with the improved clique partition algorithm based on the graph theory model exhibits higher fitness value and better optimization performance and reliability than the GA or SA algorithms alone.

scholarly journals Opportunistic In-Flight INS Alignment Using LEO Satellites and a Rotatory IMU Platform

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 280
Author(s):  
Farzan Farhangian ◽  
Hamza Benzerrouk ◽  
Rene Landry
Keyword(s):  
Kalman Filter ◽  
State Space Model ◽  
Flight Test ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Measurement Unit ◽  
Starting Point ◽  
Leo Satellites ◽  
Positioning Method ◽  
Global Navigation Satellite

With the emergence of numerous low Earth orbit (LEO) satellite constellations such as Iridium-Next, Globalstar, Orbcomm, Starlink, and OneWeb, the idea of considering their downlink signals as a source of pseudorange and pseudorange rate measurements has become incredibly attractive to the community. LEO satellites could be a reliable alternative for environments or situations in which the global navigation satellite system (GNSS) is blocked or inaccessible. In this article, we present a novel in-flight alignment method for a strapdown inertial navigation system (SINS) using Doppler shift measurements obtained from single or multi-constellation LEO satellites and a rotation technique applied on the inertial measurement unit (IMU). Firstly, a regular Doppler positioning algorithm based on the extended Kalman filter (EKF) calculates states of the receiver. This system is considered as a slave block. In parallel, a master INS estimates the position, velocity, and attitude of the system. Secondly, the linearized state space model of the INS errors is formulated. The alignment model accounts for obtaining the errors of the INS by a Kalman filter. The measurements of this system are the difference in the outputs from the master and slave systems. Thirdly, as the observability rank of the system is not sufficient for estimating all the parameters, a discrete dual-axis IMU rotation sequence was simulated. By increasing the observability rank of the system, all the states were estimated. Two experiments were performed with different overhead satellites and numbers of constellations: one for a ground vehicle and another for a small flight vehicle. Finally, the results showed a significant improvement compared to stand-alone INS and the regular Doppler positioning method. The error of the ground test reached around 26 m. This error for the flight test was demonstrated in different time intervals from the starting point of the trajectory. The proposed method showed a 180% accuracy improvement compared to the Doppler positioning method for up to 4.5 min after blocking the GNSS.

Near-Optimal Solar-Sail Orbit-Raising from Low Earth Orbit

2005 ◽  
Vol 42 (5) ◽  
pp. 954-958 ◽  
Author(s):  
Giovanni Mengali ◽  
Alessandro A. Quarta
Keyword(s):  
Solar Sail ◽  
Low Earth Orbit ◽  
Earth Orbit

One Variant of Manned Mission to Mars with a Nuclear Electric Propulsion

2011 ◽  
Vol 1 (2) ◽  
pp. 1-17 ◽  
Author(s):  
M. S. Konstantinov ◽  
H. W. Loeb ◽  
V. G. Petukhov ◽  
G. A. Popov
Keyword(s):  
Electric Propulsion ◽  
Space Mission ◽  
Optimization Criterion ◽  
Low Earth Orbit ◽  
Problem Definition ◽  
Specific Mass ◽  
Propulsion Systems ◽  
Propulsion Efficiency ◽  
Mass Minimization ◽  
Low Mass

In this paper, one possible way for implementing a manned mission to Mars is examined. Typical peculiarities of the mission are as follows: the nuclear electric propulsion; relatively low mass of the spacecraft at a low Earth orbit (200 tons) and the crew time in flight is high (900-1000 days). Space mission analysis of the chosen variant is performed. As an optimization criterion, the authors chose the fuel mass required for the flight. Under examined problem definition such mass minimization is equivalent to maximal final mass of the spacecraft and maximal permissible total mass of power and electric propulsion systems. The authors show that to implement the examined manned mission, it is necessary to create the nuclear electric power and electric propulsion systems with a specific mass lower than 12.5 kg/kW under propulsion efficiency of 0.8, specific mass of the system for propellant storage of 0.05 and manned spacecraft complex mass of 52.1 tons. Under propulsion efficiency of 0.7, specific mass of power-propulsion should be lower than 10.9 kg/kW.

Biomechanical constraints to stair negotiation

2018 ◽  
Author(s):  
Constantinos Maganaris ◽  
Vasilios Baltzopoulos ◽  
David Jones ◽  
Irene Di Giulio ◽  
Neil Reeves ◽  
...  
Keyword(s):  
Older Adults ◽  
Dynamic Stability ◽  
Ankle Joint ◽  
The Elderly ◽  
The Body ◽  
Centre Of Mass ◽  
Centre Of Pressure ◽  
Younger Adults ◽  
Stair Negotiation ◽  
Biomechanical Constraints

This chapter discusses strategies that older and younger people employ to negotiate stairs based on experiments performed on an instrumented staircase in lab environment aiming at identifying ways to reduce stair fall risk for the elderly. Stair negotiation was found to be more demanding for the knee and ankle joint muscles in older than younger adults, with the demand increasing further when the step-rise was higher. During descent of stairs with higher step-rises, older adults shifted the centre of mass (COM) posteriorly, behind the centre of pressure (COP) to prevent forward falling. A decreased step-going resulted in a slower descent of the centre of mass in the older adults and standing on a single leg for longer than younger adults. A greater reliance on the handrails and rotation of the body in the direction of the handrail was also observed when the step-going was decreased during descent, which allowed this task to be performed with better dynamic stability, by maintaining the COM closer to the COP. These findings have important implications for stair design and exercise programs aiming at improving safety on stairs for the elderly.

scholarly journals Centre of pressure versus centre of mass stabilization strategies: the tightrope balancing case

2020 ◽  
Vol 7 (9) ◽  
pp. 200111
Author(s):  
Pietro Morasso
Keyword(s):  
Degrees Of Freedom ◽  
Sensory Feedback ◽  
Sagittal Plane ◽  
Control Variable ◽  
Variable Number ◽  
Body Parts ◽  
Centre Of Mass ◽  
Centre Of Pressure ◽  
Feedback Controllers ◽  
Neuromotor Control

This study proposes a generalization of the ankle and hip postural strategies to be applied to the large class of skills that share the same basic challenge of defeating the destabilizing effect of gravity on the basis of the same neuromotor control organization, adapted and specialized to a variable number of degrees of freedom, different body parts, different muscles and different sensory feedback channels. In all the cases, we can identify two crucial elements (the CoP, centre of pressure and the CoM, centre of mass) and the central point of the paper is that most balancing skills can be framed in the CoP–CoM interplay and can be modelled as a combination/alternation of two basic stabilization strategies: the standard well-investigated COPS (or CoP stabilization strategy, the default option), where the CoM is the controlled variable and the CoP is the control variable, and the less investigated COMS (or CoM stabilization strategy), where CoP and CoM must exchange their role because the range of motion of the CoP is strongly constrained by environmental conditions. The paper focuses on the tightrope balancing skill where sway control in the sagittal plane is modelled in terms of the COPS while the more challenging sway in the coronal plane is modelled in terms of the COMS, with the support of a suitable balance pole. Both stabilization strategies are implemented as state-space intermittent, delayed feedback controllers, independent of each other. Extensive simulations support the degree of plausibility, generality and robustness of the proposed approach.

Twinkle: a low-Earth orbit, visible and infrared observatory for exoplanet and solar system spectroscopy

2020 ◽  
Author(s):  
Billy Edwards ◽  
Marcell Tessenyi ◽  
Giovanna Tinetti ◽  
Giorgio Savini ◽  
Ian Stotesbury ◽  
...  
Keyword(s):  
Solar System ◽  
Thermal Environment ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Atmospheric Composition ◽  
Orbital Parameters ◽  
Short Period ◽  
Wide Range ◽  
Solar System Objects ◽  
Scientific Potential

<p>The Twinkle Space Mission is a space-based observatory that has been conceived to measure the atmospheric composition of exoplanets, stars and solar system objects. The satellite is based on a high-heritage platform and will carry a 0.45 m telescope with a visible and infrared spectrograph providing simultaneous wavelength coverage from 0.5 - 4.5 μm. The spacecraft will be launched into a Sun-synchronous low-Earth polar orbit and will operate in this highly stable thermal environment for a baseline lifetime of seven years.</p> <p>Twinkle will have the capability to provide high-quality infrared spectroscopic characterisation of the atmospheres of hundreds of bright exoplanets, covering a wide range of planetary types. It will also be capable of providing phase curves for hot, short-period planets around bright stars targets and of providing ultra-precise photometric light curves to accurately constrain orbital parameters, including ephemerides and TTVs/TDVs present in multi-planet systems.</p> <p>Twinkle is available for researchers around the globe in two ways:</p> <p>1) joining its collaborative multi-year survey programme, which will observe hundreds of exoplanets and solar system objects; and</p> <p>2) accessing dedicated telescope time on the spacecraft, which they can schedule for any combination of science cases.</p> <p>I will present an overview of Twinkle’s capabilities and discuss some example exoplanet surveys to highlight the broad range of targets the mission could observe, demonstrating the huge scientific potential of the spacecraft.</p>

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