A free molecule aerodynamic investigation using multiple satellite analysis

Harrison, I.K.; Swinerd, G.G.

doi:10.1016/0032-0633(95)00077-1

Cited by 27 publications

(10 citation statements)

References 10 publications

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“…There is some uncertainty (Harrison & Swinerd 1996) related to what happens to the gas molecules after they strike a spacecraft surface, but in any case, mass is conserved. Therefore, assuming that there is no condensation of molecules at the surface, the expression for the number of gas molecules striking the surface per unit time will be useful:…”

Section: Pressure Force On a Front Side Flat Platementioning

confidence: 99%

An analysis of outgassing pressure forces on the Rosetta orbiter using realistic 3D+t coma simulations

Mysen¹,

Родионов

Crifo

2010

A&A

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A model for the interaction between a multicomponent Maxwellian atmosphere and a spacecraft is described. Multidimensional, time-dependent gasdynamical simulations of the gas coma around the recently reconstructed aspherical rotating nucleus of comet 67P/C-G is used to analyze the outgassing pressure forces on the ESA spacecraft Rosetta. The forces were in general found to be directed significantly away from the cometocentric position vector of the spacecraft. It was also found that in a maximum outgassing scenario at comet rendezvous, the outgassing pressure force exceeds the gravitational attraction from the nucleus in the cometocentric direction of the Sun. Furthermore, the highly non-spherical pressure field was found to undergo very large changes as the nucleus rotated. Still, it was possible to represent the mean pressure field experienced by Rosetta by a fairly simple model, which can be used for the determination of the comet mass and the so-called oblateness coefficient c 20 from the spacecraft Doppler signal. The oblateness coefficient represents a type of asphericity of the gravity field. The determination of the so-called triaxiality coefficient of the gravity field c 22 may require using the true pressure field instead of the mean pressure field.

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Section: Pressure Force On a Front Side Flat Platementioning

confidence: 99%

An analysis of outgassing pressure forces on the Rosetta orbiter using realistic 3D+t coma simulations

Mysen¹,

Родионов

Crifo

2010

A&A

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“…Обозначим O = (0, 0) начало координат. Построим две параболы p 1 и p 2 , имеющие общий фокус O и общую ось, парал-лельную вектору x (2) − x (1) ; потребуем, кроме того, чтобы парабола p 1 содер-жала точку x (1) , парабола p 2 содержала точку x (2) и чтобы пересечение выпук-лых множеств, ограниченных этими параболами, содержало отрезок [x (1) , x (2) ]. Обозначим R(ϕ 1 , ϕ 2 , δ) выпуклое множество, ограниченное параболами p 1 , p 2 и тремя прямыми x 2 = 0, x, e −δ + δ sin δ = 0 и x, e δ + δ sin δ = 0.…”

Section: рис 13 биллиардное рассеяние на ямкеunclassified

“…Оно суще-ственно использует тот факт, что окружность, проходящая через точки O, x (1) и x (1) , касается прямой x 2 = 0, и тем самым оправдывает использование окруж-ности при определении рефлектора. Свойство (26) следует из свойств (23)- (25) и того факта, что отображение ξ Свойство (26) гарантирует, что большая часть частиц, движущихся от входа рефлектора R(ϕ 1 , ϕ 2 , δ) в направлении, близком к ϕ 1 , после отражений от p 1 и p 2 покинет рефлектор.…”

Section: рис 13 биллиардное рассеяние на ямкеunclassified

Рассеяние В Биллиардах И Задачи Ньютоновской Аэродинамики

Плахов¹,

Plakhov²

2009

Uspekhi Mat. Nauk

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“…It is very sensitive to many factors, including the spacecraft material, atmosphere composition (which in turn depends on the height), angle of incidence, velocity of the satellite, etc. It is commonly accepted now that the interaction of the atmospheric particles with the surface of existing spacecraft at heights between 150 and 300 km is mostly diffuse [30,44]; however it is argued [22] that carefully manufactured clean smooth metallic surfaces would favor specular reflections.…”

Section: Possible Applications Of Invisible Bodies and Open Questionsmentioning

confidence: 99%

“…Bodies with mirror surface invisible in one direction may also be of interest. Above 150 km, the atmosphere is so rarefied that the effect of intermolecular collisions can be neglected when calculating the resistance of a body of reasonable size (several meters) [30]. As regards the body (union of two prisms) in Fig.…”

Section: Possible Applications Of Invisible Bodies and Open Questionsmentioning

confidence: 99%

Exterior Billiards

Plakhov¹

2013

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The book contains an account of results obtained by the author and his collaborators on billiards in the complement of bounded domains and their applications in aerodynamics and geometrical optics.We consider several problems related to aerodynamics of bodies in highly rarefied media. It is assumed that the medium particles do not interact with each other and are elastically reflected when colliding with the body boundary; these assumptions drastically simplify the aerodynamics and allow to reduce it to a number of purely mathematical problems.First we examine problems of minimal resistance in the case of translational motion of bodies. These problems generalize the Newton problem of least resistance; the difference is that the bodies are generally nonconvex in our case and therefore the particles can make multiple reflections from the body surface. It is proved that typically the infimum of resistance equals zero; thus, there exist 'almost perfectly streamlined' bodies.Next we consider the generalization of Newton's problem on minimal resistance of convex axisymmetric bodies to the case of media with thermal motion of particles. Two kinds of solutions are found: first, Newton-like bodies and second, shapes obtained by gluing together two Newton-like bodies along their rear ends.Further, we state results on characterization of billiard scattering by nonconvex and rough bodies; next we solve some special problems of optimal mass transportation. These two groups of results are applied to problems of minimal and maximal resistance for bodies that move forward and at the same time slowly rotate. It is found, in particular, that the resistance of a three-dimensional convex body can be increased at most twice and decreased at most by 3.05% by roughening its surface.Next, we consider a rapidly rotating rough disc moving in a rarefied medium on the plane. It is shown that the force acting on the disc is not generally parallel to the direction of the disc motion, that is, has a nonzero transversal component. This phenomenon is called Magnus effect (proper or inverse, depending on the direction of the transversal component). We show that the kind of Magnus effect depends on the kind of disc roughness, and study this dependence. The problem of finding all admissible values of the force acting on the disc is formulated in terms of a vector-valued problem of optimal mass transportation.Finally, we describe bodies that have zero resistance when translating through a medium, and state results on existence or non-existence of bodies with mirror surface invisible in one or several directions. We also consider the problem of constructing retroreflectors: bodies with specular surface that reverse the direction of any incident beam of light.

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A free molecule aerodynamic investigation using multiple satellite analysis

Cited by 27 publications

References 10 publications

An analysis of outgassing pressure forces on the Rosetta orbiter using realistic 3D+t coma simulations

An analysis of outgassing pressure forces on the Rosetta orbiter using realistic 3D+t coma simulations

Рассеяние В Биллиардах И Задачи Ньютоновской Аэродинамики

Exterior Billiards

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