Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM)

The Cosmic Ray Energetics And Mass (CREAM) instrument is configured with a suite of particle detectors to measure TeV cosmic-ray elemental spectra from protons to iron nuclei over a wide energy range. The goal is to extend direct measurements of cosmic-ray composition to the highest energies practical, and thereby have enough overlap with ground based indirect measurements to answer questions on cosmic-ray origin, acceleration and propagation. The balloon-borne CREAM was flown successfully for about 161 days in six flights over Antarctica to measure elemental spectra of Z = 1–26 nuclei over the energy range 10¹⁰ to >10¹⁴ eV. Transforming the balloon instrument into ISS-CREAM involves identification and replacement of components that would be at risk in the International Space Station (ISS) environment, in addition to assessing safety and mission assurance concerns. The transformation process includes rigorous testing of components to reduce risks and increase survivability on the launch vehicle and operations on the ISS without negatively impacting the heritage of the successful CREAM design. The project status, including results from the ongoing analysis of existing data and, particularly, plans to increase the exposure factor by another order of magnitude utilizing the International Space Station are presented.     

Analysis of CGSDS file delivery protocol: immediate NAK mode

We analyze the immediate negative acknowledgment (NAK) mode of the consultative committee for space data systems (CCSDS) file delivery protocol for the single-hop file transfer operation. We propose a timer setting rule that minimizes the expected time taken to transfer a file under the constraint that the throughput efficiency is maximized. Then, we derive the expected file delivery time and compare it with that of the deferred NAK mode. The main contribution is the closed-form expression for evaluating the performance metrics.     

Optimal m-ary data fusion with distributed sensors

An optimal data fusion rule is derived for an m-ary detection problem. Each detector determines a local decision using a local decision rule and transmits the local decision to the fusion center. Considering the reliability of local detectors, local decisions are combined to produce the final decision. In this study, based upon the maximum posterior probability concept, optimal decision rules for m-ary detection problems are proposed for the local detector and the data fusion center     

Development of a scheduling algorithm and GUI for autonomous satellite missions

In this paper, a scheduling optimization algorithm is developed and verified for autonomous satellite mission operations. As satellite control and operational techniques continue to develop, satellite missions become more complicated and the overall quantity of tasks within the missions also increases. These changes require more specific consideration and a huge amount of computational resources, for scheduling the satellite missions. In addition, there is a certain level of repetition in satellite mission scheduling activities, and hence it is highly recommended that the operation manager carefully considers and builds some appropriate strategy for performing the operations autonomously. A good strategy to adopt is to develop scheduling optimization algorithms, because it is difficult for humans to consider the many mission parameters and constraints simultaneously. In this paper, a new genetic algorithm is applied to simulations of an actual satellite mission scheduling problem, and an appropriate GUI design is considered for an autonomous satellite mission operation. It is expected that the scheduling optimization algorithm and the GUI can improve the overall efficiency in practical satellite mission operations.