Orbital Spin: A New Hypothesis to Explain Precession of Equinox—The Third Motion of Earth

In this paper, the phenomena of Earth’s motion about its own axis, the ecliptic plane of the Earth’s orbit around the Sun, the definitions of equinoxes, the precession of equinoxes, Earth’s wobble and other astronomical terminology are briefly described. Some of the existing theories explaining the precession of equinox and their inadequacies are brought out. New Hypothesis is that precession of equinoxes is a direct result of Orbital spin of Earth in a retrograde direction—a celestial phenomenon similar to that of Moon’s Orbital spin around the Earth. The study of Moon’s orbit round the Earth reveals the exact movement of Earth’s orbit, which causes precession of equinoxes without any ambiguity. The analogy presented herein demonstrates the plausible hypothesis.

Secular Effect of Geomagnetic Field and Gravitational Waves on Earth’s Satellite Orbits

In this work we study the perturbation and the change in the orbital elements due to the earth’s magnetic field and the gravitational waves. The acceleration components are derived in the radial, transverse to it and normal to the orbital plane. The equation for the rates of variation of the elements is formed and solved to find the secular variation in the element for polar and equatorial satellites.

Study and Analysis of the Orbital and Physical Properties of 2010 TK₇

In this paper we calculate the volume, mass, gravitational attraction to the Earth, angular momentum the orbit of the Trojan asteroid (TK7) [1]. In this paper, we use classical Newtonian mechanics to analyse some of the physical and orbital properties of the Trojan asteroid, which are still experimentally unknown. The asteroid should remain in Earth’s orbit for the next 100 years. We conclude by providing informed estimates of 2010 TK7’s yet unknown physical properties: i.e. mass, volume, gravitational attraction to Earth and angular momentum.

Design and analysis of the Macao Science Satellite-1's laser retro-reflector array

The origin and spatial-temporal variation of the Earth’s magnetic field(EMF)is one of the important scientific problems that has long been unsolved.The Macao Science Satellite-1(MSS-1)under construction is China’s first high-precision EMF measurement satellite.To satisfy the highly precise requirements of the MSS-1 orbit measurement,a light,high-precision,four-prism laser retroreflector array was designed.It weighs approximately 285 g,its effective reflection area is greater than 1.77 cm^(2),and its size is 100×100×41 mm.The laser retro-reflector array has excellent performance,and it can achieve a ranging precision at the subcentimeter level for satellite laser ranging.It will be developed and installed on the MSS-1 as a power-free load for high-precision orbit measurement and accurate orbit calibration.The MSS-1 is planned to be brought into the International Laser Ranging Service observations.More than 31satellite laser ranging stations in the International Laser Ranging Service around the world will be able to measure the MSS-1 with long arcs,which will support the scientific mission of high-precision EMF exploration.

Effect of Altitude, Right Ascension of Ascending Node and Inclination on Lifetime of Circular Lunar Orbits

The lifetime of a lunar satellite orbit is constrained by the non-spherical nature of the Moon’s gravity field. The orbital lifetime of lunar orbits depends significantly on the initial conditions of the orbit. Right ascension of ascending node (Ω) is one of the important orbital parameter affecting the orbital lifetime. In the present work we have analyzed the effect of Ω on the variation of lifetime with altitude for circular lunar orbits. It is found that at a particular initial altitude, a small increase in the altitude results in substantial increase in the orbital lifetime due to effect of the long periodic terms of Earth’s gravity on eccentricity and this transition altitude is different for different Ω. Further, it is observed that the variation of transition altitude with Ω follows a definite, but different trend for orbits with different inclinations. The transition altitude for polar orbits is found to be higher without the effect of Sun and Earth gravity. Variation of transition altitude with orbital inclination is also analyzed. Lifetimes of high altitude circular lunar orbits are analyzed and it is observed that at high altitudes lifetime decreases with altitude.

Numerical simulation of the sensor output on Macao Science Satellite-1

Macao Science Satellite-1(MSS-1)will be launched at the early of 2023 into a near-circular orbit.The mission is designed to measure the Earth’s geomagnetic field with unpreceded accuracy through a new perspective.The most important component installed on the satellite,to ensure high accuracy,is the deployable boom(Optical Bench).A Vector Field Magnetometer(VFM),an Advanced Stellar Compass(ASC),and a Couple Dark State Magnetometers(CDSM)are deployed on the deployable boom.In order to maximize the mission’s scientific output,a numerical simulator on MSS-1’s deployable boom was required to evaluate the adaptability of all devices on the deployable boom and assist the satellite’s data pre-processing.This paper first briefly describes the synthesis of the Earth’s total magnetic field and then describes the method simulating the output of scalar and vector magnetometers.Finally,the calibration method is applied to the synthetic magnetometer data to analyze the possible noise/error of the relevant instruments.Our results show that the simulator can imitate the disturbance of different noise sources or errors in the measuring system,and is especially useful for the satellite’s data processing group.

COMPARISON OF TWO METHODS IN SATELLITE FORMATION FLYING

Recently, the research of dynamics and control of the satellite formation flying has been attracting a great deal of attentions of the researchers. The theory of the research was mainly based on Clohessy-Wiltshire' s (C-W's) equations, which describe the relative motion between two satellites. But according to some special examples and qualitative analysis , neither the initial parameters nor the period of the solution of C-W' s equations accord with the actual situation, and the conservation of energy is no longer held. A new method developed from orbital element description of single satellite , named relative orbital element method ( ROEM) , was introduced. This new method, with clear physics conception and wide application range, overcomes the limitation of C-W s equation , and the periodic solution is a natural conclusion. The simplified equation of the relative motion is obtained when the eccentricity of the main satellite is small. Finally, the results of the two methods (C-W' s equation and ROEM) are compared and the limitations of C-W s equations are pointed out and explained.

Geophysical and Chemical Evidence in the Depletion of Ozone

The depletion of ozone is due to not only some chemical reaction, but also some physical changes, such as Solar Proton Events with solar flare, violent vortex of air currents with the changes of the earth’s rotation caused by earth’s deformation and so on We found that the tidal force by the sun makes the earth’s oblateness large on the 0° Latitude and small on the 23 5°Latitude The tidal force by the moon and nine planets can make this effect strong This is a basic reason for the creation of ozone hole and El Nino \;As shown from calculation,the earth tide by the sun makes the earth′s deformation and rotation change periodically.When the situation of the sun moves from 23.5°N to 23.5°S,the length of a day will change±0.00027s.When the earth moves from aphelion to perihelion,the length of a day will increase 0.00007s.The earth tide by the moon can increase or decrease this effect periodically.They are the reasons of the earth′s rotation decelerating from 30 July to 16 November and the ozone hole over the south Pole sky expanding with El Nino.The SSW unified stress field of the earth is the tectonic evidence of the orbital effect of the earth′s rotation and deformation.The moon′s declination and obliquity of the ecliptic determine the direction of the principal compressive stress field. Scientists discover chlorion layer in atmosphere while they studied freon.Chlorion can fly in to atmosphere from continent and ocean in many ways.The photolyte of freon is only one way of them,such as electrolysis and photolysis of sodium chloride and hydrogen chloride.The differential rotation of the earth’s layers mix ozone with chlorion and create a ozone hole over the Qinghai Tibet plateau sky.The depletion of ozone and El Nino are the results of the differential rotation.

New Interpretation of Newton’s Law of Universal Gravitation

Elliptical motions of orbital bodies are treated here using Fourier series, Fortescue sequence components and Clarke’s instantaneous space vectors, quantities largely employed on electrical power systems analyses. Using this methodology, which evidences the analogy between orbital systems and autonomous second-order electrical systems, a new theory is presented in this article, in which it is demonstrated that Newton’s gravitational fields can also be treated as a composition of Hook’s elastic type fields, using the superposition principle. In fact, there is an identity between the equations of both laws. Furthermore, an energy analysis is conducted, and new concepts of power are introduced, which can help a better understanding of the physical mechanism of these quantities on both mechanical and electrical systems. The author believes that, as a practical consequence, elastic type gravitational fields can be artificially produced with modern engineering technologies, leading to possible satellites navigation techniques, with less dependency of external sources of energy and, even, new forms of energy sources for general purposes. This reinterpretation of orbital mechanics may also be complementary to conventional study, with implications for other theories such as relativistic, quantum, string theory and others.

New Long-Term Climate Oscillations

The astronomical theory of climate change is based on the solution of differential equations describing Earth’s orbital and rotational motions. The equations are used to calculate the change in insolation over the Earth’s surface. As a result of the author’s solution of the orbital problem, the periods and amplitudes of Earth-orbit variations and their evolution have been refined. Unlike previous studies, the equations of Earth’s rotational motion are solved completely. The Earth’s rotational axis precesses relative to a direction different from the direction of the orbit’s axial precession, and oscillates with periods of half a month, half a year and 18.6 years. Also, its oscillations occur with irregular periods of several tens of thousands of years and more. All these motions lead to oscillations of the obliquity in the range of 14.7° to 32.1°, which prove to be 7 - 8 times larger than obtained by a previous theory. In the same proportion, the Earth’s insolation oscillations increase in amplitude, with insolation extremes occurring in other epochs than those in the previous theory. The amplitudes and the onset times of the extremes correlate with known paleoclimate changes. Thirteen insolation periods of paleoclimate variation over an interval of 200 thousand years are identified. From the insolation evolution calculated over a time interval of 1 million years, 6 climate gradations from very cold to very warm are identified.

Evolutionary Algorithms in Astrodynamics

This paper presents the method of solving the equations of motions by evolutionary algorithms. Starting from random trajectory, the solution is obtained by accepting the mutation if it leads to a better approximations of Newton’s second law. The general method is illustrated by finding trajectory to the Moon.

THE COMPONENT OF 29.8 YEARS IN POLAR MOTION AND △ l. o.d. AND OSCILLATION OF EARTH'S INNER CORE

This paper deals with the components of pcriod of 29.8 yr in polar motion and △ I. o. d. The oscillation of inner core (OIC), as a most possible cause of them, is proposed. Parameters of oscillation are found and its effects on Earth’s mass center (EMC), distance of observatories to EMC, gravity and latitude are estimated.

THE OSCILLATION OF CERTAIN ZONAL MEAN CHARACTERISTICS OF MOTION ON A SPHERIC EARTH'S ATMOSPHERE——PART 2:ANISOTROPIC QUASI-EDDY MOTION

This paper is an extension of the author's paper (Xie,1982) to the spherical earth.It is found that the simi- lar results are obtained under the assumption of isotropic distribution of horizontal kinetic energy along the zonal and meridional directions.It points out the limitation of the results already obtained and paves the path for the approach of anisotropie semi-eddy or quasi-eddy motion of the atmosphere.

Improved-GRACE卫星重力轨道参数优化研究

基于改进的半解析法,利用激光干涉系统星间速度误差、GPS接收机轨道位置误差和轨道速度误差以及加速度计非保守力误差影响累计大地水准面的联合误差模型,开展了我国Improved-GRACE卫星重力测量计划轨道参数的优化选取论证。模拟结果表明:1)在300阶处,基于350km轨道高度估计累计大地水准面的精度为3.993×10-1m,基于300km和250km轨道高度估计精度分别提高了8.770倍和77.145倍,基于400km和450km轨道高度估计精度分别降低了8.718倍和75.307倍;2)基于50km星间距离估计累计大地水准面的精度为3.993×10-1m,基于110km和220km星间距离估计精度分别降低了1.259倍和1.395倍;3)我国将来首颗Improved-GRACE重力卫星的平均轨道高度和平均星间距离设计为350km与50km较优。

国际下一代卫星重力测量计划研究进展

介绍下一代美国GRACE Follow-On和欧洲E.MOTION(Earth System Mass Transport Mission)卫星重力测量计划的研究进展,以期为我国下一代Post-GRACE卫星重力测量工程的成功实施提供参考依据。详细阐述了我国下一代Post-GRACE卫星重力测量工程的研究意义和科学目标,建议我国先期构建卫星精密定轨和卫星重力反演仿真模拟软件平台系统,开展重力卫星关键载荷误差分析研究,以及执行卫星重力测量任务需求。

卫星编队飞行中C-W方程与轨道根数法的比较

目前卫星编队飞行动力学与控制的研究得到了广泛的重视,这些研究的理论主要是基于描述卫星相对运动的Clohessy＿Wiltshire(C＿W)方程· 但根据特例及定性分析,表明C＿W方程在初始条件的选取、解的周期性等方面与实际情况不符,从星的能量也不守恒· 以卫星轨道根数为基础,提出了卫星编队飞行中的相对轨道根数法,克服了C＿W方程的局限性,物理概念清楚,应用范围广,解的周期性成为自然结论· 在主星为小偏心率的情况下,得到了简化的相对运动方程· 最后对两种方法进行了比较。

基于卫星轨道扰动理论的重力反演算法

为了更充分利用低轨重力卫星的高精度观测数据,根据卫星轨道的扰动理论,导出了应用卫星轨道与星间距离观测值联合反演地球重力场模型的算法.该算法的实质是将牛顿运动方程在卫星轨道处进行展开,转化为第二类Volterra积分方程,并采用基于移动窗口的9次多项式内插公式进行数值求解.给出了该算法的观测方程,用QR分解法消去局部参数矩阵,最后采用预条件共轭梯度法求解法方程.利用GRACE卫星2008-01-01～2008-08-01时间段内的轨道及星间距离观测数据,解算了120阶次的地球重力场模型SWJTU-GRACE01S,该模型在120阶处的阶方差为1.58×10^(-8),大地水准面差距累计误差为22.29cm,与美国GPS水准网比较的标准差为0.793m,结果表明:SWJTU-GRACE01S模型精度介于EIGEN-GRACE01S与EIGEN-GRACE02S模型之间,从而验证了该算法的有效性.

基于Hill方程的螺线轨道仿真、分析与控制

研究对数螺线在航天器相对运动控制问题中的应用可行性。把对数螺线形式的相对运动轨迹代入到Hill方程中，推导出控制律并进行仿真分析，由于沿迹向控制会造成相对运动漂移，推导出只应用径向与法向控制来实现螺线轨道的控制律，并提出用沿迹向速度冲量来控制漂移的方法。仿真结果表明螺线轨道概念可应用于相对运动控制问题中，而“径向与法向连续推力控制”加“沿迹向冲量控制”的螺线轨道实现方式简便、可行且有效。

低热层大气探测立方星翱翔一号轨道寿命分析

西北工业大学翱翔一号作为欧盟第七框架协议-QB50立方星网络大气探测项目中50颗立方星中的一员，将通过搭载多种大气传感器实现对于低热层大气中性粒子、带电离子、大气阻力参数等的全面探测。对翱翔一号在低热层飞行过程中影响其轨道寿命的主要因素进行分析，并针对不同的发射月份采取多种大气模型进行了分析与仿真，通过仿真可以看出同一个月内发射，当采用不同大气模型时轨道的寿命具有差异。采用同一大气模型，在不同的月份进行发射，立方星的在轨天数也不同，大约在90～120天之间。由于QB50项目中50颗立方星质量相近，轨道高度、轨道倾角相同，因此，文中的研究工作对整个卫星网络的在轨时间估计、任务规划、对各卫星再入返回时间估计分析有重要借鉴意义。

地球质心的运动对卫星轨道的影响

由地心运动引起的引力位1次项系数不为零会对卫星轨道产生摄动。文中主要通过模拟计算来研究地心运动或坐标系统不自洽引起的地心偏离,从而对不同轨道根数的卫星轨道产生的摄动量级。实验表明地心运动对卫星轨道的影响,在高精度精密定轨和反演地球重力场中也是需要顾及的一项内容,特别是在坐标系统不自洽的情况下,影响更大。