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1.
Delta-v requirements for earth co-orbital rendezvous missions   总被引：1，自引：0，他引：1  
Earth co-orbital asteroids present advantages as potential targets for future asteroid rendezvous missions. Their prolonged proximity to Earth facilitates communication, while their Earth-like orbits mean a steady flux of solar power and no significant periodic heating and cooling of the spacecraft throughout the course of the mission. Theoretical studies show that low-inclination co-orbital orbits are more stable than high-inclination orbits. As inclination is the most significant indicator of low delta-v rendezvous orbits, there is the potential for a large population of easily accessible asteroids, with favorable engineering requirements. This study first looks at phase-independent rendezvous orbits to a large number of objects, then looks in more detail at the phase-dependent orbits to the most favorable objects. While rendezvous orbits to co-orbital objects do not have a low delta-v necessarily, some objects present energy requirements significantly less than previous rendezvous missions. Currently we find no ideal co-orbital asteroids for rendezvous missions, although theoretical Earth Trojans present very low-energy requirements for rendezvous.  相似文献   

2.
In-situ investigation of asteroids is the next logical step in understanding their exact surface mineralogy, petrology, elemental abundances, particle size distribution, internal structure, and collisional evolution. Near-Earth asteroids (NEAs) provide us with ample opportunities for in-situ scientific exploration with lower Δv requirements and subsequently lower costs than their main belt counterparts. The ASTEX mission concept aims at surface characterization of two compositionally diverse NEAs, one with primitive and the other with a strong thermally evolved surface mineralogy. Here we present the first results of our ground-based characterization of potential ASTEX mission targets using the SpeX instrument on the NASA IRTF. Of the four potential targets we characterized, two (1991 JW and 1998 PA) have compositions similar to ordinary chondrite mineralogy. The other two targets (1994 CC and 1999 TA10) are thermally evolved objects with igneous formation histories. While 1994 CC is a triplet system and thus very challenging to orbit the V-type NEA, 1999 TA10 is the most interesting scientific ASTEX target identified so far.  相似文献   

3.
MarcoPolo-R near earth asteroid sample return mission   总被引：3，自引：0，他引：3  
MarcoPolo-R is a sample return mission to a primitive Near-Earth Asteroid (NEA) proposed in collaboration with NASA. It will rendezvous with a primitive NEA, scientifically characterize it at multiple scales, and return a unique sample to Earth unaltered by the atmospheric entry process or terrestrial weathering. MarcoPolo-R will return bulk samples (up to 2?kg) from an organic-rich binary asteroid to Earth for laboratory analyses, allowing us to: explore the origin of planetary materials and initial stages of habitable planet formation; identify and characterize the organics and volatiles in a primitive asteroid; understand the unique geomorphology, dynamics and evolution of a binary NEA. This project is based on the previous Marco Polo mission study, which was selected for the Assessment Phase of the first round of Cosmic Vision. Its scientific rationale was highly ranked by ESA committees and it was not selected only because the estimated cost was higher than the allotted amount for an M class mission. The cost of MarcoPolo-R will be reduced to within the ESA medium mission budget by collaboration with APL (John Hopkins University) and JPL in the NASA program for coordination with ESA’s Cosmic Vision Call. The baseline target is a binary asteroid (175706) 1996 FG3, which offers a very efficient operational and technical mission profile. A binary target also provides enhanced science return. The choice of this target will allow new investigations to be performed more easily than at a single object, and also enables investigations of the fascinating geology and geophysics of asteroids that are impossible at a single object. Several launch windows have been identified in the time-span 2020–2024. A number of other possible primitive single targets of high scientific interest have been identified covering a wide range of possible launch dates. The baseline mission scenario of MarcoPolo-R to 1996 FG3 is as follows: a single primary spacecraft provided by ESA, carrying the Earth Re-entry Capsule, sample acquisition and transfer system provided by NASA, will be launched by a Soyuz-Fregat rocket from Kourou into GTO and using two space segment stages. Two similar missions with two launch windows, in 2021 and 2022 and for both sample return in 2029 (with mission duration of 7 and 8?years), have been defined. Earlier or later launches, in 2020 or 2024, also offer good opportunities. All manoeuvres are carried out by a chemical propulsion system. MarcoPolo-R takes advantage of three industrial studies completed as part of the previous Marco Polo mission (see ESA/SRE (2009)3, Marco Polo Yellow Book) and of the expertise of the consortium led by Dr. A.F. Cheng (PI of the NASA NEAR Shoemaker mission) of the JHU-APL, including JPL, NASA ARC, NASA LaRC, and MIT.  相似文献   

4.
The international Rosetta mission, a cornerstone mission of the european space agency scientific Programme, was launched on 2nd March 2004 on its 10 years journey towards a rendezvous with comet Churyumov-Gerasimenko (Gardini et al., 1999). During its interplanetary flight towards its target Rosetta crosses the asteroid belt twice with the opportunity to observe at close quarters two asteroids: (2867)-Šteins in 2008 and (21)-Lutetia in 2010. The spacecraft design was such that these opportunities could be fully exploited to deliver valuable data to the scientific community. The mission trajectory was controlled such that Rosetta would fly next to asteroid Šteins on the 5th of September 2008 with a relative speed of 8.6 km/s at a minimum distance of 800 km. Mission operations have been carefully planned to achieve the best possible flyby scenario and scientific outcome. The flyby scenario, the optical navigation campaign, and the planning of the scientific observations had to be adapted by the Mission and the Science Operations Centres to the demanding requirements expressed by the scientific community. The flyby was conducted as planned with a large number of successful observations.  相似文献   

5.
Recently, with new trajectory design techniques and use of low-thrust propulsion systems, missions have become more efficient and cheaper with respect to propellant. As a way to increase the mission’s value and scientific return, secondary targets close to the main trajectory are often added with a small change in the transfer trajectory. As a result of their large number, importance and facility to perform a flyby, asteroids are commonly used as such targets. This work uses the Primer Vector theory to define the direction and magnitude of the thrust for a minimum fuel consumption problem. The design of a low-thrust trajectory with a midcourse asteroid flyby is not only challenging for the low-thrust problem solution, but also with respect to the selection of a target and its flyby point. Currently more than 700,000 minor bodies have been identified, which generates a very large number of possible flyby points. This work uses a combination of reachability, reference orbit, and linear theory to select appropriate candidates, drastically reducing the simulation time, to be later included in the main trajectory and optimized. Two test cases are presented using the aforementioned selection process and optimization to add and design a secondary flyby to a mission with the primary objective of 3200 Phaethon flyby and 25143 Itokawa rendezvous.  相似文献   

6.
MARCO POLO: near earth object sample return mission   总被引：1，自引：0，他引：1  
MARCO POLO is a joint European–Japanese sample return mission to a Near-Earth Object. This Euro-Asian mission will go to a primitive Near-Earth Object (NEO), which we anticipate will contain primitive materials without any known meteorite analogue, scientifically characterize it at multiple scales, and bring samples back to Earth for detailed scientific investigation. Small bodies, as primitive leftover building blocks of the Solar System formation process, offer important clues to the chemical mixture from which the planets formed some 4.6 billion years ago. Current exobiological scenarios for the origin of Life invoke an exogenous delivery of organic matter to the early Earth: it has been proposed that primitive bodies could have brought these complex organic molecules capable of triggering the pre-biotic synthesis of biochemical compounds. Moreover, collisions of NEOs with the Earth pose a finite hazard to life. For all these reasons, the exploration of such objects is particularly interesting and urgent. The scientific objectives of MARCO POLO will therefore contribute to a better understanding of the origin and evolution of the Solar System, the Earth, and possibly Life itself. Moreover, MARCO POLO provides important information on the volatile-rich (e.g. water) nature of primitive NEOs, which may be particularly important for future space resource utilization as well as providing critical information for the security of Earth. MARCO POLO is a proposal offering several options, leading to great flexibility in the actual implementation. The baseline mission scenario is based on a launch with a Soyuz-type launcher and consists of a Mother Spacecraft (MSC) carrying a possible Lander named SIFNOS, small hoppers, sampling devices, a re-entry capsule and scientific payloads. The MSC leaves Earth orbit, cruises toward the target with ion engines, rendezvous with the target, conducts a global characterization of the target to select a sampling site, and delivers small hoppers (MINERVA type, JAXA) and SIFNOS. The latter, if added, will perform a soft landing, anchor to the target surface, and make various in situ measurements of surface/subsurface materials near the sampling site. Two surface samples will be collected by the MSC using “touch and go” manoeuvres. Two complementary sample collection devices will be used in this phase: one developed by ESA and another provided by JAXA, mounted on a retractable extension arm. After the completion of the sampling and ascent of the MSC, the arm will be retracted to transfer the sample containers into the MSC. The MSC will then make its journey back to Earth and release the re-entry capsule into the Earth’s atmosphere.  相似文献   

7.
Near-Earth asteroids have attracted attention for both scientific and commercial mission applications. Due to the fact that the Earth–Moon \(\hbox {L}_{1}\) and \(\hbox {L}_{2}\) points are candidates for gateway stations for lunar exploration, and an ideal location for space science, capturing asteroids and inserting them into periodic orbits around these points is of significant interest for the future. In this paper, we define a new type of lunar asteroid capture, termed direct capture. In this capture strategy, the candidate asteroid leaves its heliocentric orbit after an initial impulse, with its dynamics modeled using the Sun–Earth–Moon restricted four-body problem until its insertion, with a second impulse, onto the \(\hbox {L}_{2}\) stable manifold in the Earth–Moon circular restricted three-body problem. A Lambert arc in the Sun-asteroid two-body problem is used as an initial guess and a differential corrector used to generate the transfer trajectory from the asteroid’s initial obit to the stable manifold associated with Earth–Moon \(\hbox {L}_{2}\) point. Results show that the direct asteroid capture strategy needs a shorter flight time compared to an indirect asteroid capture, which couples capture in the Sun–Earth circular restricted three-body problem and subsequent transfer to the Earth–Moon circular restricted three-body problem. Finally, the direct and indirect asteroid capture strategies are also applied to consider capture of asteroids at the triangular libration points in the Earth–Moon system.  相似文献   

8.
In asteroid rendezvous missions, the dynamical environment near an asteroid's surface should be made clear prior to launch of the mission. However, most asteroids have irregular shapes,which lower the efficiency of calculating their gravitational field by adopting the traditional polyhedral method. In this work, we propose a method to partition the space near an asteroid adaptively along three spherical coordinates and use Chebyshev polynomial interpolation to represent the gravitational acceleration in each cell. Moreover, we compare four different interpolation schemes to obtain the best precision with identical initial parameters. An error-adaptive octree division is combined to improve the interpolation precision near the surface. As an example, we take the typical irregularly-shaped nearEarth asteroid 4179 Toutatis to demonstrate the advantage of this method; as a result, we show that the efficiency can be increased by hundreds to thousands of times with our method. Our results indicate that this method can be applicable to other irregularly-shaped asteroids and can greatly improve the evaluation efficiency.  相似文献   

9.
Near-Earth asteroids (10302) 1989 ML and (4660) Nereus have attracted much attention as candidates for the next generation of deep space explorations. In the study, the maximum Lyapunov exponent (MLE) and MEGNO (Mean Exponential Growth factor of Nearby Orbits) index are calculated after considering the effects of major objects in the Solar system, and the stabilities of these two asteroids are discussed. For each asteroid, 1000 clonal particles consistent with the observational uncertainties are generated from a multivariate normal distribution. Statistical results display probably emerging regions of each asteroid within 0.1 million years, and provide distributions of occurrence times in the phase space of semi-major axis versus eccentricity. We estimate the probability of close encounters and collisions between the asteroid and Earth or other planets. Furthermore, secular resonances, Kozai resonance, and mean motion resonances are analyzed for nominal orbits of the two asteroids. We conclude that 1989 ML is in the region dominated by mean motion resonances with terrestrial planets. The probability of close encounters with them is relatively small, therefore its orbit is relatively stable. Nereus is located in a region that can have close-encounters with the Earth, and it has an extremely unstable orbit.  相似文献   

10.
近地小行星(10302) 1989 ML和(4660) Nereus作为下一代深空探测的候选目标一直备受关注. 在考虑太阳系主要天体的动力学背景下, 通过计算最大Lyapunov指数(MLE)及MEGNO (Mean Exponential Growth factor of Nearby Orbits)指数讨论它们的稳定性. 同时, 对每个小行星, 在其观测误差范围内按多元正态分布各选取1000个克隆粒子, 通过统计分析显示这两个小行星在10万年内可能的运动范围, 给出半长径-偏心率空间中的出现次数分布图, 并统计小行星与地球或其他大行星之间的密近交汇及碰撞的概率. 此外还对这两个小行星的标称轨道进行长期共振、Kozai共振及平运动共振的动力学分析. 综上得出结论, 1989 ML处在平运动共振主导的区域, 发生密近交汇的概率较小, 从而其轨道相对较稳定; 而Nereus处在地球的密近交汇区域, 轨道极不稳定.  相似文献   

11.
Specific information on the surface morphology, composition, mean density, and internal structure of asteroids, which is necessary to advance our understanding of asteroids, can be obtained only by a detailed investigation of individual bodies: this will require space missions to individual targets. Since an essential characteristic of the asteroids is their variety, several objects must be visited. The Ariane launcher developed presently in Europe makes a multiple flyby mission possible. The first results of our feasibility study are particularly encouraging: during one revolution, five to six preselected main belt asteroids may be approached to within 1000 km with relative velocities which lie between 3 and 14 km/sec using a total impulse correction on the order of 1 to 2 km/sec. The weight of the spacecraft, excluding the engine and the propellant, would be at least 250 kg. This allows a scientific payload of 50 to 60 kg, in which priority will be given to an imaging system and radar altimeter.  相似文献   

12.
Asteroids and comets are of strategic importance for science in an effort to understand the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this paper, we consider the currently known NEO population and define a family of so-called Easily Retrievable Objects (EROs), objects that can be transported from accessible heliocentric orbits into the Earth’s neighbourhood at affordable costs. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun–Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy Earth transfers for asteroid material. A catalogue of asteroid retrieval candidates is then presented. Despite the highly incomplete census of very small asteroids, the ERO catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of $\Delta v$ Δ v . Moreover, the approach proposed represents a robust search and ranking methodology for future retrieval candidates that can be automatically applied to the growing survey of NEOs.  相似文献   

13.
The ESA astrometric mission Gaia, due for a launch in late 2011, will observe a huge number of asteroids (∼350,000 brighter than V<20) with an unprecedented positional precision (at the sub-milliarcsecond level). This precision will play an important role for the mass determination of about hundred minor planets with a relative precision better than 50%. Presently, due primarily to their perturbations on Mars, the uncertainty in the masses of the largest asteroids is the limiting factor in the accuracy of the solar system ephemerides. Besides, such high precision astrometry will enable to derive direct measurements of the masses of the largest asteroids which are of utmost significance for the knowledge of their physical properties. The method for computing the masses is based on the analysis of orbital perturbations during close encounters between massive asteroids (perturbers) and several smaller minor planets (targets). From given criteria of close approaches selection, we give the list of asteroids for which the mass can be determined, and the expected precision of these masses at mission completion. We next study the possible contribution of the ground-based observations for the mass determination in some special observation cases of close approaches.  相似文献   

14.
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15.
The PLANCK mission, originally devised for cosmological studies, offers the opportunity to observe Solar System objects at millimetric and submillimetric wavelengths. In this paper we concentrate on the asteroids of the Main Belt, a large class of minor bodies in the Solar System. At present, more that 40 000 of these asteroids have been discovered and their detection rate is rapidly increasing. We intend to estimate the number of asteroids that can be detected during the mission and to evaluate the strength of their signal. We have rescaled the instrument sensitivities, calculated by the LFI and HFI teams for sources fixed in the sky, introducing some degradation factors to properly account for moving objects. In this way a detection threshold is derived for asteroidal detection that is related to the diameter of the asteroid and its geocentric distance. We have developed a numerical code that models the detection of asteroids in the LFI and HFI channels during the mission. This code performs a detailed integration of the orbits of the asteroids in the timespan of the mission and identifies those bodies that fall in the beams of PLANCK and their signal strength. According to our simulations, a total of 397 objects will be observed by PLANCK and an asteroidal body will be detected in some beam in 30% of the total sky scan-circles. A significant fraction (in the range from 50 to 100 objects) of the 397 asteroids will be observed with a high S/N ratio. Flux measurements of a large sample of asteroids in the submillimeter and millimeter range are relevant since they allow to analyze the thermal emission and its relation to the surface and regolith properties. Furthermore, it will be possible to check on a wider base, the two standard thermal models, based on a nonrotating or rapidly rotating sphere. Our method can also be used to separate Solar System sources from cosmological sources in the survey. This work is based on PLANCK LFI activities.  相似文献   

16.
The mission designed to explore asteroids has nowadays become a hot spot of deep space exploration, and the accessibility of the explored objects is the most important problem to make clear. The number of asteroids is large, and it needs an enormous quantity of calculations to evaluate the accessibility for all asteroids. In this paper, based on the direct transfer strategy, we have calculated the accessibility for the different regions of the solar system and compared it with the distribution of asteroids. It is found that most main-belt asteroids are accessible by the direct transfer orbit with the launch energy of C3 = 50 km2/s2, and that with an additional small velocity correction, the designed trajectory is able to realize the multi-target flyby mission. Such a kind of multi-target flyby can reach the same effect of the orbit manoeuvre in the ΔV-EGA trajectory scheme[1,2]. Being assisted by the earth's gravity, the accompanying flight with asteroids or the exploration of more distant asteroids can be realized with a lower energy. In the end, as an example, a trajectory scheme is given, in which the probe flies by multiple main-belt asteroids at first, then with the assistance of the earth's gravity, it makes the accompanying flight to a more distant asteroid.  相似文献   

17.
The thermophysics of asteroids has become an important frontier for the research of asteroids in recent years. In this paper, we have introduced the thermophysical models commonly used in this field, by using these thermophysical models and combining with the data observed by the space or ground-based IR telescopes, some thermophysical parameters of asteroids, such as the thermal inertia, geometric albedo, effective diameter, surface roughness, and surface temperature, etc., can be derived. We have mentioned also the shape model and IR observation of asteroids, as well as the obtained thermophysical parameters for a part of asteroids. These thermophysical parameters can be further applied to studying the asteroids’ Yarkovsky effect, YORP effect, and so on, even can provide the relevant information for the spacecraft landing on the asteroid surface and the return mission of a spacecraft after the asteroid sampling.  相似文献   

18.
The authors here propose a mission scenario, aimed at close exploration of a Near-Earth Asteroid, exploiting low-V resonant trajectories. These trajectories allow repeated fly-bys of a chosen target. A selection procedure, which has been used to find some interesting mission opportunities in the 2005-2015 time frame, is described and the corresponding detailed mission profiles are derived, using an indirect optimization method.  相似文献   

19.
At present,optical autonomous navigation has become a key technology in deep space exploration programs.Recent studies focus on the problem of orbit determination using autonomous navigation,and the choice of filter is one of the main issues.To prepare for a possible exploration mission to Mars,the primary emphasis of this paper is to evaluate the capability of three filters,the extended Kalman filter(EKF),unscented Kalman filter(UKF) and weighted least-squares(WLS) algorithm,which have different initial states during the cruise phase.One initial state is assumed to have high accuracy with the support of ground tracking when autonomous navigation is operating; for the other state,errors are set to be large without this support.In addition,the method of selecting asteroids that can be used for navigation from known lists of asteroids to form a sequence is also presented in this study.The simulation results show that WLS and UKF should be the first choice for optical autonomous navigation during the cruise phase to Mars.  相似文献   

20.
The Yarkovsky effect, which causes a slow drifting of the orbital elements (mainly the semimajor axis) of km-sized asteroids and meteors, is the weak non-gravitational force experienced by these bodies due to the emission of thermal photons. This effect is believed to play a role in the delivery of near-Earth asteroids (NEAs) from the main belt, in the spreading of the orbital elements of asteroid families, and in the orbital evolution of potentially hazardous asteroids.Here we present preliminary results of simulationing indicating that the perturbations induced by the Yarkovsky effect on the positions of some tens of NEAs can be observed by means of the high-precision astrometric observations that will be provided by the ESA mission Gaia.  相似文献   

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