With the rapid development and influence of open source software technology, related common software in various fields and industries has gradually opened up. On the other hand, open source software is also used for system development. In the field of aerospace, NASA is at the forefront of open source. It has opened 1072 open source software and design tools, covering the entire development and application process of spacecraft. In recent years, the application of high-performance components and high-speed buses on spacecraft has greatly improved the computing and storage capabilities of satellites. On-board software has a lot of room for development, especially for the miniaturization, integration, and intelligence of satellites. The development of globalization has a great role in promoting. This article has conducted research on NASA's open source software, conducted an in-depth analysis of some open source projects, and combined with project requirements, developed a satellite health monitoring prototype system based on open source software. At the same time, the development trend of open source software technology in the aerospace field and satellites The intelligent development ideas were discussed.
The rapid development of open source software has gradually changed the pattern of software development in the world. As a leader in the field of space exploration, NASA released the 2017-2018 software catalog in March 2017[1], open source a series of aerospace-related projects, including design simulation tools, application software and code used for many years Most of the libraries are free to use, such as the CCSDS CFDP file transfer protocol, a standard tool for exchanging large files with the spacecraft. In the past, the research of the thesis focused on NASA’s technical achievement transformation policies and mechanisms. From a technical point of view, this article conducted research on NASA open source software, secondary development practices, and thought about the development of open source technology to software-defined satellite technology, and the solution to satellite intelligence. There is a certain reference significance to the problem of chemistry.
1
Overview of NASA open source software development
1.1 Technology transfer plan
Beginning in 1964, NASA, which has been leading the world with cutting-edge science and technology, has established a technology transfer plan to establish a long-term mechanism for aerospace technology to serve the people's livelihood. It publishes a Spinoff report every year. So far, more than 2,000 technologies have been successfully transferred. To the civilian field. While fulfilling its motto "We strive to reach new heights and discover the unknown for the welfare of mankind", NASA has established a technology transfer program that enables many small and medium-sized enterprises to use NASA's scientific research results to start businesses, and new fields are widely used. The technology transfer program established by NASA in the aerospace field has become a well-functioning and highly effective mechanism for the transformation of high-tech achievements, accelerating the transformation of scientific and technological achievements.
1.21.2 Open source progress and purpose
As part of the technology transfer plan, NASA has released a large number of open source software and tools in aerospace projects on its official website. Currently, there are a total of 1072 available program software, covering project management, data and image processing, power supply systems, spacecraft design and 15 aspects such as integrated tools and autonomous systems are shown in Figure 1. These codes come from 11 R&D centers and institutions including NASA Ames, JPL, Jonhson, Armstrong, etc. NASA’s approach has two purposes. On the one hand, it hopes to improve code quality, accelerate development through open source community peer review, and receive more suggestions for project improvement. On the other hand, it maximizes the visibility and impact of NASA research, while also integrating technology. Transfer to enterprises and individuals for the development of the latest technology in new fields.
Figure 1 Software catalog classification
Fig.1 NASA Open Source Software Category
2
NASA typical open source project
2.1 Livingstone2 (L2)
Livingstone2[2-3] was developed by NASA Ames Center. It is a model-based fault diagnosis and recovery engine. The purpose is to make complex systems such as spacecraft continuously autonomous and intelligent, and achieve self-perception and diagnosis of system status with minimal manual intervention. And respond to abnormal conditions, especially in the face of hardware failures or unknown events.
By establishing a set of multi-level qualitative logic models, detecting and diagnosing system faults by comparing model prediction data with actual sensor data, tracking the state of the system, and giving suggestions based on different states to continue the system's operation, the principle is shown in Figure 2. Shown. L2 has been implemented and applied on several test beds including the X34 propulsion system and the International Space Station, and it has also conducted flight tests on the Earth Observation Satellite 1 (EO-1).
Figure 2 L2 diagnosis principle
Fig. 2 NASA L2 Diagnosis Principle
2.2 Trick spacecraft simulation environment
The Trick spacecraft simulation environment [4] is developed by NASA Johnson Space Center, allowing users to establish simulation applications for all stages of spacecraft development, including early design, performance index evaluation, flight software development and testing, flight process dynamic analysis, software and Closed loop testing of hardware. The purpose is to provide a universal simulation capability so that experts in various fields can focus more on models in specific fields instead of simulation function applications such as task sequencing, data storage, etc. But this software is only open to US citizens. Figure 3 shows the flow of Trick Monte Carlo's advanced simulation function, which allows users to repeatedly simulate different inputs for continuous optimization.
Figure 3 Trick's Monte Carlo function process
Fig.3 Trick Monte Carlo Advanced Simulation Capability Flow
2.3Open MCT[5]
Open MCT (Open Mission Control Technologies) is a next-generation mission control framework with data visualization, which can be used on desktop and mobile respectively. It is developed by NASA Ames Center for spacecraft mission analysis, operation control and planning. As a general and open basic platform, users can carry out secondary development on the basis of Open MCT, and develop applications such as mission planning, control and data analysis for different spacecraft. The system effect diagram is shown in Figure 4.
Figure 4 The effect of Open MCT system
Fig.4 Open MCT General View
3
Satellite health monitoring prototype system based on open source software
3.1 System introduction
The system is used to monitor the health status of the satellite platform, including but not limited to CPU temperature, GPU temperature, CPU usage, RAM usage, ROM usage, attitude measurement parameters (such as acceleration sensor XYZ, magnetometer XYZ, etc.) and other information, Encapsulate the state of health information (SOH: State Of Health) in the CCSDS data packet format, and send it to the ground station system through the radio frequency link, and display the information in the form of a chart.
3.2 System Architecture
The system uses Raspberry PI+PC to build a verification prototype system. RPI is used as a satellite terminal, running Linux system and flight control system software, application software SOH, PC terminal is used as a ground terminal, running Linux system and ground station software, connected via WiFi wireless link, After the system is running, it can perform telemetry and remote control functions. The system architecture diagram is as follows:
Figure 5 System architecture
Fig.5 System architecture
3.3 System results
The system integrates the technical advantages of open source software, and customizes improvements according to requirements. After three months of testing, the software works normally, the system runs stably, and a simple health status monitoring function is realized. In the next step, more components can be integrated through the bus, and the corresponding functional software development can be enriched and improved. Ground system operation diagram, see Figure 6
Figure 6 Ground system operation diagram
Fig.6 Ground System View
4
Thinking and Enlightenment
4.1 Thinking of open source software in the aerospace field
In the field of aerospace software, NASA open sourced various application software, code libraries and tools from spacecraft simulation, design tools, spaceborne software, ground mission control, and structural material design tools. The motivation for open source on the official website is to use the open source community to improve software quality. To some extent, using these codes, especially secondary development, will make companies with weaker technical capabilities rely on NASA's basic code and affect their independent innovation capabilities.
The importance of aerospace software to space assets is self-evident, especially the basic core software. In terms of operating systems, the VxWorks operating system is still the mainstream choice for most domestic aerospace projects. It is worth thinking about the open source research operating system. On the other hand, the common system of artificial intelligence technology is Linux, and many machine learning algorithms are developed based on Linux. The development of satellite intelligence is to choose an open source route, to gather intelligence, or to absorb mature intelligent algorithms in traditional fields. This is also worthwhile. The research direction to be explored.
4.2 Open source will be an important driver of commercial aerospace enterprise technology
Open source software has the characteristics of openness, sharing, and freedom. Enterprises can avoid reinventing the wheel. They can quickly build a system with minimal human, material and financial resources. They can be customized flexibly on the basis of open source software. Through the power of the community, the software can be improved. It is stable and safer, and can find and fix security vulnerabilities in time. A very successful example. After Android was released as open source in 2007, the camp showed explosive growth and became the mobile operating system with the largest share [6].
The pursuit of more stability, safety, and reliability has led to higher costs for aerospace software development and testing. Due to the pursuit of high reliability and heavy responsibility, the development of software has been slower than the development of the Internet software industry. The development of commercial aerospace, combined with open source technology, is expected to change this situation in terms of software quality and software cost.
Concluding remarks
NASA's open source project software, part of the code is iteratively updated every day, which improves the quality of the software and further reduces the risk of application in aerospace projects. This has a great reference for the development of software-defined satellite technology.
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