contains 233 terms · This page displays 30 terms, you can enter keywords to query the complete range
Aerospace先锋异常先锋异常现象或先锋效应是先锋 10 号和先锋 11 号航天器在离开太阳系的轨道上经过约 20 个天文单位（3×109 公里；2×109 英里）后观察到的与预测加速度的偏差。多年来，这种明显的异常现象一直备受关注，但随后被航天器热损失引起的各向异性辐射压力所解释。两艘先锋号航天器都在逃离太阳系，但在太阳引力的影响下速度减慢。经过对导航数据的仔细检查，发现航天器的减速速度略高于预期。其效应是向太阳的加速度极小，为(8.74±1.33)×10−10 m/s2，相当于十年内出站速度降低1 km/h。这两艘航天器分别于1972年和1973年发射。
The Pioneer anomaly, or Pioneer effect, was the observed deviation from predicted accelerations of the Pioneer 10 and Pioneer 11 spacecraft after they passed about 20 astronomical units (3×109 km; 2×109 mi) on their trajectories out of the Solar System. The apparent anomaly was a matter of much interest for many years but has been subsequently explained by anisotropic radiation pressure caused by the spacecraft's heat loss. Both Pioneer spacecraft are escaping the Solar System but are slowing under the influence of the Sun's gravity. Upon very close examination of navigational data, the spacecraft were found to be slowing slightly more than expected. The effect is an extremely small acceleration towards the Sun, of (8.74±1.33)×10−10 m/s2, which is equivalent to a reduction of the outbound velocity by 1 km/h over a period of ten years. The two spacecraft were launched in 1972 and 1973.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在轨道力学中，猪排图（也称为猪排图）是一种图表，显示等特征能量 (C3) 与特定星际飞行的发射日期和到达日期组合的水平曲线。该图表显示了局部最小值周围区域的特征能量范围，类似于猪排片的形状。通过检查猪排图的结果，工程师可以确定何时存在与特定航天器的能力兼容的发射机会（“发射窗口”）。给定的轮廓（称为“猪排曲线”）代表常数 C3，而“猪排”的中心是最佳的最小 C3。
In orbital mechanics, a porkchop plot (also pork-chop plot) is a chart that shows level curves of equal characteristic energy (C3) against combinations of launch date and arrival date for a particular interplanetary flight. The chart shows the characteristic energy ranges in zones around the local minima, which resembles the shape of a porkchop slice. By examining the results of the porkchop plot, engineers can determine when a launch opportunity exists (a 'launch window') that is compatible with the capabilities of a particular spacecraft. A given contour, called a porkchop curve, represents constant C3, and the center of the porkchop the optimal minimum C3.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在航空航天工程中，推进剂质量分数是飞行器质量中未到达目的地的部分，通常用作飞行器性能的衡量标准。换句话说，推进剂质量分数是推进剂质量与飞行器初始质量之间的比率。在航天器中，目的地通常是轨道，而对于飞机来说，目的地是其着陆位置。较高的质量分数代表设计中较轻的重量。另一个相关的衡量标准是有效负载分数，它是有效负载的初始重量的分数。它可以应用于车辆、车辆的级或火箭推进系统。
In aerospace engineering, the propellant mass fraction is the portion of a vehicle's mass which does not reach the destination, usually used as a measure of the vehicle's performance. In other words, the propellant mass fraction is the ratio between the propellant mass and the initial mass of the vehicle. In a spacecraft, the destination is usually an orbit, while for aircraft it is their landing location. A higher mass fraction represents less weight in a design. Another related measure is the payload fraction, which is the fraction of initial weight that is payload. It can be applied to a vehicle, a stage of a vehicle or to a rocket propulsion system.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 无推进剂航天器推进是任何通过与环境相互作用而不是排出机载推进剂来加速航天器的航天器推进系统，这是化学和电力推进系统使用的更传统的方法。可以利用各种物理现象来实现无需推进剂的推进，最显着的是重力、辐射压力、太阳风、行星磁场或高层大气中的空气动力阻力。几种无推进剂技术已在飞行中得到验证，而其他技术则处于不同的开发阶段。空气制动首先由 Hiten (1991) 在地球上进行了演示，此后已被多个行星际航天器使用。太阳航行虽然没有广泛使用，但已经在包括行星际航天器在内的几艘航天器的飞行中进行了演示。
Propellantless spacecraft propulsion is any spacecraft propulsion system that accelerates the craft by interacting with the environment rather than expelling on-board propellant, which is the more traditional approach used by chemical and electric propulsion systems. Various physical phenomena can be exploited to achieve propulsion without propellant, most notably gravity, radiation pressure, solar wind, planetary magnetic fields or aerodynamic drag in the upper atmosphere. Several propellantless technologies have been demonstrated in flight, while others are at varying stages of development. Aerobraking was first demonstrated around Earth by Hiten (1991), and has since been used by several interplanetary spacecraft. Solar sailing, while not widely used, has been demonstrated in flight by several spacecraft, including interplanetary ones.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 赝态轨迹模型是一种在存在多个行星大小的天体的情况下计算航天器轨迹的近似方法。该方法由 J.S. 开发为天体动力学计算模型。 Wilson 改进了修补圆锥曲线逼近的方法。
The pseudostate trajectory model is an approximation method to calculate spacecraft trajectories in the presence of more than one planetary-sized bodies. This method was developed as an astodynamical calculations model by J.S. Wilson in order to improve upon the method of patched conic approximation.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在天体动力学和天体力学中，径向轨迹是角动量为零的开普勒轨道。径向轨迹上的两个物体沿直线直接靠近或远离彼此。
In astrodynamics and celestial mechanics a radial trajectory is a Kepler orbit with zero angular momentum. Two objects in a radial trajectory move directly towards or away from each other in a straight line.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在航空航天工程中，火箭质量比或简称质量比是火箭效率的衡量标准。它描述了带有推进剂的飞行器比没有推进剂的飞行器质量大多少。它是火箭的湿质量（运载工具加上内容物加上推进剂）与其干质量（运载工具加上内容物）的比率。更高效的火箭设计需要更少的推进剂来实现给定的目标，因此具有更低的质量比；然而，对于任何给定的效率，较高的质量比通常允许车辆实现更高的 Delta-V。质量比对于粗略的火箭计算来说是一个有用的量：它是一个很容易从 Δ v {\displaystyle \Delta {v}} 或火箭和推进剂质量推导出来的数字，因此可以作为两者之间的便捷桥梁。
In aerospace engineering, rocket mass ratio or simply mass ratio is a measure of the efficiency of a rocket. It describes how much more massive the vehicle is with propellant than without. It is the ratio of the rocket's wet mass (vehicle plus contents plus propellant) to its dry mass (vehicle plus contents). A more efficient rocket design requires less propellant to achieve a given goal, and would therefore have a lower mass ratio; however, for any given efficiency a higher mass ratio typically permits the vehicle to achieve higher delta-v. The mass ratio is a useful quantity for back-of-the-envelope rocketry calculations: it is an easy number to derive from either Δ v {\displaystyle \Delta {v}} or from rocket and propellant mass, and therefore serves as a handy bridge between the two.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在引力二体问题中，两个轨道物体的比轨道能 ε {\displaystyle \varepsilon } （或比维生能）是它们的机械能（它们的相互势能 ε p {\displaystyle \varepsilon _{p}} 和它们的动能 ε k {\displaystyle \varepsilon _{k}} 之和）除以它们的约化质量的常数商。
In the gravitational two-body problem, the specific orbital energy ε {\displaystyle \varepsilon } (or specific vis-viva energy) of two orbiting bodies is the constant quotient of their mechanical energy (the sum of their mutual potential energy, ε p {\displaystyle \varepsilon _{p}} , and their kinetic energy, ε k {\displaystyle \varepsilon _{k}} ) to their reduced mass.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 天体动力学和天文学中的影响球（SOI）是扁球体形状的区域，其中特定天体对轨道物体施加主要引力影响。因此，它是引力场的主导部分。它通常用于描述太阳系中行星主导周围物体（例如卫星）轨道的区域，尽管存在质量更大但距离更远的太阳。在修补圆锥近似中，用于使用二体近似、椭圆和双曲线来估计在不同物体的邻域之间移动的物体的轨迹，SOI 被视为轨迹切换其受哪个质量场影响的边界。不要将其与远远超出影响范围的活动范围相混淆。
A sphere of influence (SOI) in astrodynamics and astronomy is the oblate spheroid-shaped region where a particular celestial body exerts the main gravitational influence on an orbiting object. As such it is the dominating part of a gravitational field. It is usually used to describe the areas in the Solar System where planets dominate the orbits of surrounding objects such as moons, despite the presence of the much more massive but distant Sun. In the patched conic approximation, used in estimating the trajectories of bodies moving between the neighbourhoods of different bodies using a two-body approximation, ellipses and hyperbolae, the SOI is taken as the boundary where the trajectory switches which mass field it is influenced by. It is not to be confused with the sphere of activity which extends well beyond the sphere of influence.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 静石（静态和卫星这两个词的组合）是一种假想的人造卫星，它利用太阳帆以仅靠重力无法允许的方式不断改变其轨道。通常，静石会利用太阳帆“悬停”在原本无法作为稳定地球同步轨道的位置。有人提出，静石将保留在地球两极上方的固定位置，利用反射的阳光来抵消将其拉下的重力。静态陨石还可能利用其帆来改变更常规轨道的形状或速度，具体取决于特定静态陨石的用途。滑石的概念是由 Robert L. 大约在同一时间独立发明的。
A statite (a portmanteau of the words static and satellite) is a hypothetical type of artificial satellite that employs a solar sail to continuously modify its orbit in ways that gravity alone would not allow. Typically, a statite would use the solar sail to "hover" in a location that would not otherwise be available as a stable geosynchronous orbit. Statites have been proposed that would remain in fixed locations high over Earth's poles, using reflected sunlight to counteract the gravity pulling them down. Statites might also employ their sails to change the shape or velocity of more conventional orbits, depending upon the purpose of the particular statite. The concept of the statite was invented independently and at about the same time by Robert L.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 超同步轨道是周期大于同步轨道的轨道，或者是长轴大于同步轨道的轨道。同步轨道的周期等于包含轨道重心的物体的自转周期。
A supersynchronous orbit is an orbit with a period greater than that of a synchronous orbit, or an orbit whose major axis is larger than that of a synchronous orbit. A synchronous orbit has a period equal to the rotational period of the body which contains the barycenter of the orbit.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 终结者轨道是航天器绕太阳系小天体运行的轨道，其中轨道平面大致垂直于太阳系天体-太阳线，因此航天器沿着天体的终结者运行，即其发光半球和未发光半球之间的边界。天体动力学文献中也将它们描述为终结平面、黎明-黄昏轨道或“3 点钟/9 点钟”轨道。由于太阳辐射压力是小天体弱引力中的主要扰动，因此这种几何形状提供了大多数其他轨道方向所没有的被动稳定性，并且它已成为小行星交会任务的标准操作配置。
Terminator orbits are spacecraft orbits about a small Solar System body in which the orbital plane is held approximately perpendicular to the body–Sun line, so that the spacecraft follows the body's terminator, the boundary between its lit and unlit hemispheres. They are also described in the astrodynamics literature as the terminator plane, a dawn–dusk orbit, or a "3 o'clock/9 o'clock" orbit. Because solar radiation pressure is a dominant perturbation in the weak gravity of a small body, this geometry provides passive stability that most other orbit orientations do not, and it has become a standard operational configuration for asteroid rendezvous missions.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 跨地球注入（TEI）是一种推进机动，用于将航天器设置在与地球影响范围相交的轨道上，通常使航天器处于自由返回轨道上。该机动是由火箭发动机执行的。
A trans-Earth injection (TEI) is a propulsion maneuver used to set a spacecraft on a trajectory which will intersect the Earth's sphere of influence, usually putting the spacecraft on a free return trajectory. The maneuver is performed by a rocket engine.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在轨道力学中，转移轨道是一种中间椭圆轨道，用于将轨道机动中的航天器从一个圆形或大部分圆形轨道移动到另一个轨道。转移轨道有多种类型，其能量效率和转移速度各不相同。其中包括： 霍曼转移轨道，一种椭圆轨道，用于在同一平面内的两个不同高度的圆形轨道之间转移航天器 双椭圆转移，一种较慢的转移方法，但可能比霍曼转移轨道更有效 地球静止转移轨道或地球同步转移轨道通常也是霍曼转移轨道 月球转移轨道是接触近地轨道和月球轨道的轨道。
In orbital mechanics, a transfer orbit is an intermediate elliptical orbit that is used to move a spacecraft in an orbital maneuver from one circular, or largely circular, orbit to another. There are several types of transfer orbits, which vary in their energy efficiency and speed of transfer. These include: Hohmann transfer orbit, an elliptical orbit used to transfer a spacecraft between two circular orbits of different altitudes in the same plane Bi-elliptic transfer, a slower method of transfer, but one that may be more efficient than a Hohmann transfer orbit Geostationary transfer orbit or geosynchronous transfer orbit is usually also a Hohmann transfer orbit Lunar transfer orbit is an orbit that touches Low Earth orbit and a lunar orbit.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 转位、对接和抽出（通常缩写为转位和对接）是 1969 年至 1972 年阿波罗登月任务期间执行的一种操作，用于将阿波罗登月舱 (LM) 从其适配器外壳中取出，该适配器外壳将其固定在土星 V 运载火箭的上级并保护其免受发射时的空气动力应力。该操作涉及指挥舱飞行员将阿波罗指挥和服务模块（CSM）与适配器分离，转动 CSM，并将其机头与登月舱对接，然后将组合航天器拉离上级。它是在阿波罗飞船进行跨月注入机动后不久进行的，该机动使阿波罗飞船进入了为期三天的月球轨道。对接创建了一个连续的加压隧道，允许宇航员在 CSM 和 LM 之间进行内部转移。
Transposition, docking, and extraction (often abbreviated to transposition and docking) was a maneuver performed during Apollo lunar landing missions from 1969 to 1972, to withdraw the Apollo Lunar Module (LM) from its adapter housing which secured it to the Saturn V launch vehicle upper stage and protected it from the aerodynamic stresses of launch. The maneuver involved the command module pilot separating the Apollo Command and Service Module (CSM) from the adapter, turning the CSM around, and docking its nose to the Lunar Module, then pulling the combined spacecraft away from the upper stage. It was performed shortly after the trans-lunar injection maneuver that placed the Apollo spacecraft on a three-day trajectory to the Moon. The docking created a continuous, pressurized tunnel which permitted the astronauts to transfer internally between the CSM and the LM.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在天体力学中，中心配置是一个点质量系统，其特性是每个质量都被系统的组合引力直接拉向质心，加速度与其距中心的距离成正比。尽管只有一维、二维和三维与物理空间中的天体力学直接相关，但在任何维度的欧几里得空间中提出的 n 体问题中都研究了中心配置。
In celestial mechanics, a central configuration is a system of point masses with the property that each mass is pulled by the combined gravitational force of the system directly towards the center of mass, with acceleration proportional to its distance from the center. Central configurations are studied in n-body problems formulated in Euclidean spaces of any dimension, although only dimensions one, two, and three are directly relevant for celestial mechanics in physical space.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在天体动力学或天体力学中，双曲轨迹或双曲轨道（来自牛顿理论：双曲线形状）是任何物体围绕中心天体以足够的速度逃离中心物体引力场的轨迹；表示为轨道偏心率，由大于 1 的任何数字指定。在简单化的假设下，沿着该轨道行进的物体将滑向无穷远，相对于中心物体达到最终的超速度。与抛物线轨迹一样，所有双曲轨迹也是逃逸轨迹。双曲轨迹轨道的比能量为正。用于引力弹弓的行星飞越可以使用双曲轨迹在行星的影响范围内进行描述。
In astrodynamics or celestial mechanics, a hyperbolic trajectory or hyperbolic orbit (from Newtonian theory: hyperbola shape) is the trajectory of any object around a central body with enough velocity to escape the central object's gravitational field; expressed as orbital eccentricity designated by any number more than 1. Under simplistic assumptions a body traveling along this trajectory will coast towards infinity, settling to a final excess velocity relative to the central body. As with parabolic trajectories, all hyperbolic trajectories are also escape trajectories. The specific energy of a hyperbolic trajectory orbit is positive. Planetary flybys, used for gravitational slingshots, can be described within the planet's sphere of influence using hyperbolic trajectories.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在经典物理学和狭义相对论中，惯性参考系（也称为惯性空间或伽利略参考系）是物体表现出惯性的参考系：它们相对于参考系保持静止或匀速运动，直到受到外力作用。在这样的框架中，无需校正加速度即可观察自然法则。所有零加速度的参考系都处于相对于彼此恒定直线运动（直线运动）的状态。在这样的框架中，作用在其上的净力为零的物体被认为以恒定速度移动，或者等效地，牛顿第一运动定律成立。这种框架被称为惯性框架。一些物理学家，比如艾萨克·牛顿，最初认为其中一个框架是绝对的——即以恒星近似的框架。
In classical physics and special relativity, an inertial frame of reference (also called an inertial space or a Galilean reference frame) is a frame of reference in which objects exhibit inertia: they remain at rest or in uniform motion relative to the frame until acted upon by external forces. In such a frame, the laws of nature can be observed without the need to correct for acceleration. All frames of reference with zero acceleration are in a state of constant rectilinear motion (straight-line motion) with respect to one another. In such a frame, an object with zero net force acting on it, is perceived to move with a constant velocity, or, equivalently, Newton's first law of motion holds. Such frames are known as inertial. Some physicists, like Isaac Newton, originally thought that one of these frames was absolute — the one approximated by the fixed stars.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ n 体编排是 n 体问题的周期性解决方案，其中所有物体沿着单个轨道均匀分布。该术语由 Chenciner 和 Montgomery 于 2000 年首次提出。其中一种轨道是圆形轨道，在等边三角形的角上具有相等的质量；另一种是 8 字形轨道，由 Cristopher Moore 于 1993 年首次以数值方式发现，随后由 Chenciner 和 Montgomery 证明其存在。编排可以使用变分方法来发现，最近，拓扑方法已被用来尝试在平面情况下进行分类。掌握特定解决方案（例如编排）的知识非常有用，因为不可能通过显式方法解决 N > 2 的 N 体问题。
An n-body choreography is a periodic solution to the n-body problem in which all the bodies are equally spread out along a single orbit. The term was originated in 2000 by Chenciner and Montgomery. One such orbit is a circular orbit, with equal masses at the corners of an equilateral triangle; another is the figure-8 orbit, first discovered numerically in 1993 by Cristopher Moore and subsequently proved to exist by Chenciner and Montgomery. Choreographies can be discovered using variational methods, and more recently, topological approaches have been used to attempt a classification in the planar case. Having knowledge of specific solutions such as choreographies can be incredibly useful as it is not possible to solve the N-body problem for N > 2 through explicit means.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在物理学中，n 体问题是预测一组天体在引力作用下的个体运动的问题。解决这个问题的动机是了解太阳、月球、行星和可见恒星的运动。经典物理问题可以表述如下：有限数量粒子系统中的每个粒子都受到来自所有其他粒子的牛顿引力的作用，而不受到其他力的作用。如果给定系统的初始状态，粒子将如何运动？二体问题已经解决，下面讨论。对于三个或更多物体，只有在特定情况下才能完全解决问题。一般来说，问题是混沌的，只能用数值方法求解。广义相对论中的 n 体问题要解决起来要困难得多。
In physics, the n-body problem is the problem of predicting the individual motions of a group of celestial objects interacting with each other gravitationally. Solving this problem has been motivated by the desire to understand the motions of the Sun, Moon, planets, and visible stars. The classical physical problem can be stated as follows: Each particle in a system of a finite number of particles is subjected to a Newtonian gravitational attraction from all the other particles, and to no other forces. If the initial state of the system is given, how will the particles move? The two-body problem has been solved and is discussed below. For three or more bodies the problem can only be solved completely in particular cases. In general, the problem is chaotic and can only be solved numerically. The n-body problem in general relativity is considerably more difficult to solve.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在航天学中，航天器姿态控制是控制航天器（飞行器或卫星）相对于惯性参考系或其他实体（例如天球、某些场和附近物体等）的方向的过程。控制飞行器姿态需要执行器施加将飞行器定向到所需姿态所需的扭矩，并需要算法根据当前姿态和所需姿态的规范来命令执行器。在进行姿态控制之前和过程中，必须进行航天器姿态确定，这需要传感器进行绝对或相对测量。研究传感器、执行器和算法组合的更广泛的综合领域称为制导、导航和控制，其中还涉及非姿态概念，例如位置确定和导航。
In astronautics, spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle or satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle attitude requires actuators to apply the torques needed to orient the vehicle to a desired attitude, and algorithms to command the actuators based on the current attitude and specification of a desired attitude. Before and during attitude control can be performed, spacecraft attitude determination must be performed, which requires sensors for absolute or relative measurement. The broader integrated field that studies the combination of sensors, actuators and algorithms is called guidance, navigation and control, which also involves non-attitude concepts, such as position determination and navigation.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 当流体在物体周围流动时，流体会对物体施加力。升力是垂直于迎面流动方向的力的分量。它与阻力形成对比，阻力是平行于流动方向的力的分量。升力通常沿向上方向作用，以抵抗重力，但它可以沿垂直于流动的任何方向作用。如果周围的流体是空气，则该力称为空气动力。在水或任何其他液体中，它被称为水动力。动态升力与流体中的其他类型的升力不同。空气静力升力或浮力，其中内部流体比周围流体轻，不需要运动，并且由气球、飞艇、飞船、船只和潜艇使用。
When a fluid flows around an object, the fluid exerts a force on the object. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it may act in any direction perpendicular to the flow. If the surrounding fluid is air, the force is called an aerodynamic force. In water or any other liquid, it is called a hydrodynamic force. Dynamic lift is distinguished from other kinds of lift in fluids. Aerostatic lift or buoyancy, in which an internal fluid is lighter than the surrounding fluid, does not require movement and is used by balloons, blimps, dirigibles, boats, and submarines.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在流体动力学，失速（英语：stall）是指翼型气动迎角（Angle of attack）增加到一定程度（达到临界值）时，翼型所产生的升力（lift force）突然减小、飞机的飞行高度快速降低的一种状态。失速并不意味著发动机停止了工作或飞机失去了前进的速度。 由于大部分有关失速的讨论都与航空有关，以下集中论述失速与飞机（固定翼飞机）的关系。
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack exceeds its critical value. The critical angle of attack is typically about 15°, but it may vary significantly depending on the fluid, foil – including its shape, size, and finish – and Reynolds number. Stalls in fixed-wing aircraft are often experienced as a sudden reduction in lift as the airflow separates from the upper surface, which may be due to an increase in the wing's angle of attack past the critical angle or a decrease in the critical angle of attack. The former may be due to slowing down (below stall speed), the latter by accretion of ice on the wings. A stall does not mean that the engine(s) have stopped working, or that the aircraft has stopped moving—the effect is the same even in an unpowered glider aircraft. Because stalls are most commonly discussed in connection with aviation, this article discusses stalls as they relate mainly to aircraft, in particular fixed-wing aircraft. The principles of stall discussed here translate to foils in other fluids as well.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 牛顿运动定律是描述物体运动与作用在其上的力之间关系的三个物理定律。这些定律为牛顿力学提供了基础，可以解释如下：物体保持静止状态，或以恒定速度沿直线运动，除非受到力的作用。在任何时刻，物体上的净力等于物体的加速度乘以其质量，或者等效地，物体的动量随时间变化的速率。如果两个物体相互施加力，这些力的大小相同但方向相反。运动三大定律最初由艾萨克·牛顿 (Isaac Newton) 在其 1687 年出版的《Philosophiæ Naturalis Principia Mathematica》（自然哲学的数学原理）中首次提出。
Newton's laws of motion are three physical laws that describe the relationship between the motion of an object and the forces acting on it. These laws, which provide the basis for Newtonian mechanics, can be paraphrased as follows: A body remains at rest, or in motion at a constant speed in a straight line, unless it is acted upon by a force. At any instant of time, the net force on a body is equal to the body's acceleration multiplied by its mass or, equivalently, the rate at which the body's momentum is changing with time. If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), originally published in 1687.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 惯性是运动中的物体保持运动状态和静止的物体保持静止状态的自然趋势，除非有力导致其速度改变。它是经典物理学的基本原理之一，由艾萨克·牛顿在他的第一运动定律（也称为惯性原理）中进行了描述。它是质量的主要表现之一，是物理系统的核心定量特性之一。牛顿写道：第一定律。每个物体都保持静止状态，或者沿直线匀速运动，除非它受到施加在其上的力的作用而被迫改变该状态。牛顿在 1687 年的著作《自然哲学数学原理》中将惯性定义为一种属性：定义 III。
Inertia is the natural tendency of objects in motion to stay in motion and objects at rest to stay at rest, unless a force causes its velocity to change. It is one of the fundamental principles in classical physics, and is described by Isaac Newton in his first law of motion (also known as The Principle of Inertia). It is one of the primary manifestations of mass, one of the core quantitative properties of physical systems. Newton writes: LAW I. Every object perseveres in its state of rest, or of uniform motion in a right line, except insofar as it is compelled to change that state by forces impressed thereon. In his 1687 work Philosophiæ Naturalis Principia Mathematica, Newton defined inertia as a property: DEFINITION III.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在经典力学中，冲量（用 J 或 Imp 表示）是物体动量的变化。它最常用于描述在短时间内作用的力，特别是在撞击和碰撞的情况下，它因此而得名。冲量是一个矢量，这意味着它既有描述动量变化量的大小，也有描述动量变化方向的方向。对于短时间作用的力，冲量通常被理想化，以便将力产生的动量变化建模为瞬时发生。这种变化是阶跃变化，在物理上是不可能的。然而，这是计算理想碰撞效果的有用模型（例如在视频游戏物理引擎中）。
In classical mechanics, impulse (symbolized by J or Imp) is the change in momentum of an object. It is most often used to describe forces which act over short time periods, specifically in the case of impacts and collisions, for which it gets its namesake. Impulse is a vector quantity, meaning it has both a magnitude, which describes the amount by which the momentum changed, and a direction, which describes the direction in which the momentum changed. For a force acting over a short time, the impulse is often idealized so that the change in momentum produced by the force is modelled as happening instantaneously. This sort of change is a step change, and is not physically possible. However, this is a useful model for computing the effects of ideal collisions (such as in videogame physics engines).
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在经典力学中，恢复系数（COR，也用 e 表示）是两个表面之间碰撞弹性的度量。牛顿恢复定律指出，碰撞后两个表面立即分离的相对速度与碰撞前两个表面接近的相对速度成正比，比例常数称为恢复系数，是一对表面属性的无量纲参数。在大多数现实世界的碰撞中，恢复系数介于 0 和 1 之间，其中 1 表示完全弹性碰撞（其中物体在没有动能损失的情况下反弹，但方向相反），而 0 表示完全非弹性碰撞（其中物体根本不反弹，最终合并）。
In classical mechanics, the coefficient of restitution (COR, also denoted by e), is a measure of the springiness of collisions between two surfaces. Newton's law of restitution states that the relative speed of separation of two surfaces immediately after a collision is directly proportional to the relative speed of approach of the surfaces immediately before the collision, the constant of proportionality being called the coefficient of restitution, a dimensionless parameter that is a property of a pair of surfaces. In most real-world collisions, the coefficient of restitution is between 0 and 1, where 1 represents a perfectly elastic collision (in which the objects rebound with no loss of kinetic energy but in the opposite directions) and 0 a perfectly inelastic collision (in which the objects do not rebound at all, and end up coalescing).
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗ 在经典力学里，对于一个动力系统，随着时间的演进，所有保持不变的物理量都称为守恒量（conserved quantity），又称为运动常数。由于很多物理定律会表达某种守恒行为，对应的守恒量时常会出现于真实系统。例如，假设在某系统内涉及的作用力是保守力，则此系统的能量是守恒量。假设涉及的作用力是有心力，则此系统的角动量是守恒量。
A conserved quantity is a property or value that remains constant over time in a system even when changes occur in the system. In mathematics, a conserved quantity of a dynamical system is formally defined as a function of the dependent variables, the value of which remains constant along each trajectory of the system. Not all systems have conserved quantities, and conserved quantities are not unique, since one can always produce another such quantity by applying a suitable function, such as adding a constant, to a conserved quantity. Since many laws of physics express some kind of conservation, conserved quantities commonly exist in mathematical models of physical systems. For example, any classical mechanics model will have mechanical energy as a conserved quantity as long as the forces involved are conservative.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 张量（英语：Tensor）在数学中是一个代数对象，描述了与矢量空间相关的代数对象集之间的多重线性映射。张量可以作为不同的对象之间的映射，例如矢量、标量以及其他张量。张量有很多种类型，包括标量和矢量、对偶矢量、矢量空间之间的多重线性映射，甚至还有一些运算，例如点积。张量的定义独立于任何基，尽管它们通常由与特定坐标系相关的基中的分量来表示；这些分量形成一个数组，可以将其视为高维矩阵。 n {\displaystyle n} 维空间上的 r {\displaystyle r} 阶张量有 n r {\displaystyle n^{r}} 个分量， r {\displaystyle r} 也称为该张量的秩（与矩阵的秩和阶均无关系）。
In mathematics, a tensor is an algebraic object that describes a multilinear relationship between sets of algebraic objects associated with a vector space. Tensors may map between different objects such as vectors, scalars, and even other tensors. There are many types of tensors, including scalars and vectors (which are the simplest tensors), dual vectors, multilinear maps between vector spaces, and even some operations such as the dot product. Tensors are defined independent of any basis, although they are often referred to by their components in a basis related to a particular coordinate system; those components form an array, which can be thought of as a high-dimensional matrix.
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements.
View content license ↗ 在物理学和工程学中，自由体图（FBD；也称为力图）是一种图形说明，用于可视化给定条件下自由体上所施加的力、力矩以及所产生的反应。它描绘了一个物体或连接的物体，以及作用在物体上的所有施加的力和力矩以及反作用力。该主体可以由多个内部构件（例如桁架）组成，或者是一个紧凑的主体（例如梁）。解决复杂问题可能需要一系列自由体和其他图表。有时，为了以图形方式计算合力，所施加的力被排列为力多边形或力多边形的边缘（参见§力多边形）。
In physics and engineering, a free body diagram (FBD; also called a force diagram) is a graphical illustration used to visualize the applied forces, moments, and resulting reactions on a free body in a given condition. It depicts a body or connected bodies with all the applied forces and moments, and reactions, which act on the body(ies). The body may consist of multiple internal members (such as a truss), or be a compact body (such as a beam). A series of free bodies and other diagrams may be necessary to solve complex problems. Sometimes in order to calculate the resultant force graphically the applied forces are arranged as the edges of a polygon of forces or force polygon (see § Polygon of forces).
Sources, licensing and use
Wikipedia contributors · Retrieved2026-10-04 · CC BY-SA 4.0. Introductions were extracted as plain text and shortened. Language versions may emphasize different aspects.For concept reference; consult the original standards for authoritative requirements. The Chinese definition is a machine-assisted translation of the cited English introduction; check technical terminology against the original.
View content license ↗