Types Of Space Missions Research Articles

A Method for Analog Space Missions Risk Analysis

In this paper, we provide a general risk evaluation method for analog simulation missions, in terms of identification of potential hazards and risks, which could affect the positive outcome of a pre-designed mission. The risk analysis method considers the risk evaluation of each mission's foreseen experiment, and the evaluation of other general factors which could have an impact on the entire operation. The scope of this analysis is to ensure that all the undertaken operations are analysed and well defined. We paid special attention to the assessment of the safety issues related to the execution of the experiments. The methodology includes elements of the Fault Tree Analysis (FTA) and the development of a specific risk-reduction strategy, appropriately scaled and simplified for the space simulation mission scope. Also, we introduced the Risk Cube concept, a new useful tool that can be applied to other types of Space missions. It represents a higher level of abstraction, yet characterized by a simpler approach. The added value of the Risk Cube concept is that it is possible to identify all the domains of occurrence of the risks, visualize the interconnection of the different risks, and contribute to creating a mental map whose aim is to identify all the possible factors and requirements that could have some influence on the outcome of the risk analysis.

Summary of Research on Satellite Mission Planning Based on Multi-Agent-System

With the continuous development of space science, the number and types of space missions are increasing day by day. Reasonable mission planning plays an important role in fulfilling space missions to the maximum extent with limited satellite resources. Satellite mission planning modelling based on multi-agent system (MAS) is a bottom-up method. This article introduces three specific solution methods and compares and analyses them. Finally, the future development direction of the MAS mission planning problem is analysed.

Recent advances in contact dynamics and post-capture control for combined spacecraft

The combined spacecraft is increasingly demanded to accomplish various types of space missions. Therefore, the dynamics and control technologies of combined spacecraft are significantly important to ensure the success of future space explorations. Several kinds of combined spacecraft can be obtained by different capturing approaches, and the dynamical property of combined spaceraft varies dramatically between different categories. Therefore, the control system should be designed according to the specific combined spacecraft category and mission requirement. Moreover, the contacting behavior between the end-effector and the target has been a complex problem that may influence significantly the performance of the combined spacecraft control system. Up to now, the complete review of the combined spacecraft contact dynamics and control technologies has rarely been reported. With these motivations, this paper presents the review and prospects of the combined spacecraft contact dynamics and control technologies including the capturing strategy analysis, contact dynamics modeling, inertia parameter estimation and post-capture controller design.

Distance estimation in OFDM inter-satellite links

One of the practical solutions for space deployment of large-scale scientific instruments is satellite formation flying. In this type of space mission, several smaller satellites have the ability to interact and cooperate with each other via inter-satellite links (ISL) for tasks commonly performed by a larger and more complex satellite. Formation flying missions require accurate knowledge of the satellite positioning with regard to orientation and distance. This paper proposes a distance estimation method applicable in an Orthogonal Frequency-Division Multiplexing (OFDM) ISL. In the proposed technique, called enhanced wide-lane (EWL), the distance is estimated using an OFDM training symbol, and the measurement is based on the correlation between the received symbol and a stored replica. More precisely, a coarse estimation is obtained by detecting the correlation maximum, then it is refined by measuring the correlation phase. The theoretical considerations regarding the precision of the estimation and the influence of frequency offset and multipath propagation are validated using MATLAB simulations and an experimental testbed built with Universal Software Radio Peripheral (USRP) platforms. The results show that the precision of EWL is of sub-mm level in the absence of frequency offset and multipath propagation.

Performance model for space-based laser debris sweepers

This paper outlines the capabilities of a space-based laser for active debris removal in the range of 1cm to 10cm. As for respective ground based solutions, the space based laser ablates small bits of mass from the targeted debris objects. When directed properly, the resulting propulsive effect will lower the targets׳ perigees and facilitate an expeditious burnup in the Earth׳s atmosphere.For this particular type of space mission, a mission-specific performance model has been developed. It does not only deliver the removal performance (e.g. the number of objects removed) of a given mission scenario. It also provides insight into the relevant mechanisms that are driving the performance. The user can tell why a particular scenario is strong or weak, and iteratively tune the mission and the system parameters of the orbital debris sweeper. This parametric model allows case studies, parameter studies and optimizations of mission scenarios.As an illustration of the application of this model, a baseline mission scenario for a debris sweeper mission is being presented. Three system driver quantities for the overall mission concept are highlighted, and a reasonable parameter range for each of them is presented. Finally, it is shown how a single laser could already reduce the debris density in low Earth orbit (LEO) by more than 20% in 10 years.

Optimal Trajectories for Spacecraft Rendezvous

The efficient execution of a rendezvous maneuver is an essential component of various types of space missions. This work describes the formulation and numerical investigation of the thrust function required to minimize the time or fuel required for the terminal phase of the rendezvous of two spacecraft. The particular rendezvous studied concerns a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and separation velocity in all three dimensions. First, the time-optimal rendezvous is investigated followed by the fuel-optimal rendezvous for three values of the max-thrust acceleration via the sequential gradient-restoration algorithm. Then, the time-optimal rendezvous for given fuel and the fuel-optimal rendezvous for given time are investigated. There are three controls, one determining the thrust magnitude and two determining the thrust direction in space.

Space solar cells—tradeoff analysis

This paper summarizes the study that had the objective to tradeoff space solar cells and solar array designs to determine the best choice of solar cell and array technology that would be more beneficial in terms of mass, area and cost for different types of space missions. Space solar cells, which are commercially now available in the market and to be available in the near future, were considered for this trade study. Four solar array designs: rigid, flexible, thin film flexible and concentrator solar arrays were considered for assessment. Performance of the solar cells along with solar array designs were studied for two types of space missions: geo synchronous orbit (GEO) and low earth orbit (LEO) spacecraft. The Solar array designs assumed were to provide 15 kW power for 15 years mission life in GEO and 5 kW power for 5 years mission life in LEO altitudes. To perform tradeoff analysis a spread sheet model was developed that calculates the size, mass and estimates the cost of solar arrays based on different solar cell and array technologies for given set of mission requirements. Comparative performance metrics (W/kg, W/m 2 , kg/m 2 , and $/W) were calculated for all solar arrays studied and compared, at the solar array subsystem level and also at the spacecraft system level. The trade analysis results show that high-efficiency multijunction solar cells bring lot of cost advantages for both types of missions. The trade study also show that thin film solar cells with moderate efficiency with ultra lightweight flexible array design may become competitive with well-established single crystalline solar cell technologies in the future.

SNAP Radioisotopic Power Systems

Auxiliary power systems deriving their energy from radionuclide decay have been under development for more than five years under Atomic Energy Commission sponsorship. Called SNAP, the program has been oriented toward satisfying the need for small, compact, lightweight and reliable power supplies for space systems. Radioisotopic power relates to the generation of heat by absorption of electromagnetic and particulate radiations emitted by a carefully sealed source of radioisotopes. The heat is then partially converted into electricity by a thermoelectric or thermionic conversion device, with the remainder rejected to the external environment. It is the intent of this paper to present a status report on SNAP radioisotopic devices and to explore some of the unique aspects of the technical problems encountered. Since these power systems have no moving parts, they lend themselves appropriately to the performance of the following types of space missions: 1. Satellites operating on equatorial orbits where the continuous power demand exceeds the storage cycle capability. 2. Satellites operating for considerable periods of time in the Van Allen radiation belts where solar cell output is significantly degraded. 3. Lunar explorations, such as NASA's Surveyor program, where storage requirements during the lunar night become excessive. 4. Venus surveys where solar energy would be excluded by the atmosphere. 5. Space probes away from the sun where the decrease in solar flux becomes significant.