After the completion of the design and development of satellites, the systems are normally subjected to waiting periods that span for several years before the identification of an appropriate launch opportunity.
Design and Implementation Cost:
The third major problem in the development and implementation of satellite communication is the software development costs. This includes money spent on all bus systems, ground support equipment, systems engineering, communication payloads, program management, and integration and test. In most cases, the development and implementation costs are difficult to estimate since there are recurring and non-recurring cost drivers in the process. The non-recurring cost drivers include heritage, number of prototypes and engineering models, and technology readiness while the recurring cost-drivers are complexity, project scope, and quantity of production.
The production quantity refers to the number of flight units developed, combined, and tested on similar contract to the development initiatives. While the development and production initiatives tend to overlap, there are production contracts with high production capabilities and minimal non-recurring costs. However, the development and implementation costs tend to be high when there is a higher production quantity. Therefore, the development costs of a satellite communication system are strongly linked to its production quantity.
Regardless of the impact of production quantity on the design costs, the development and implementation of satellite communication systems is usually costly. Notably, these costs are influenced by cost drivers that are classified into three categories i.e. primary, secondary, and tertiary categories. The primary cost drivers are the unit weight that accounts for a huge portion of the budget whereas the secondary drivers are the quantity on contract and the tertiary drivers are the complexity characteristics of satellite system. it's reported that complexity drivers tend to perform poorly over time as yesterday's complex system may be the low-cost alternative of today's system (Burgess & Menton, p. 25).
Low-Cost Satellite Systems:
With the growing need for effective communication within a wide geographic area, satellite communication systems have emerged as the means to handle this growing need and promote effective communication. Nonetheless, the development and implementation of these systems has been largely affected by several challenges, especially the costs associated with them. As a result, low-cost satellite subsystems have been developed as an alternative to this problem in order to enhance satellite communication.
The main reason attributed to the development of low-cost satellite system is because they provide an economical and useful means for enhancing satellite communications. Low-cost satellite systems use the Control Area Network (CAN) protocol to offer a communication link across several subsystems. Despite of its effective performance as tested on previous satellite mission, the Control Area Network has a restricted data rate and consists of a harness overhead. In most cases, the reduction of harness results in the lessening of spacecraft construction complexities and reduction of total mass. The lessening of mass can also take place through the elimination of electronic interference boards on subsystem electronics.
While the data rate of the Control Area Network is restricted to approximately 32 kbps, there are other types of these systems with a higher baud rate estimated at 38.4 kbps with a fraction of the mass. The achievement of efficient communication across satellites through low-cost systems requires the formation of a communication web.
Requirements for Developing Low-Cost Satellite Systems:
There are some necessary requirements and consideration for the development of low-cost satellite systems that enhance communication. In addition to the necessary components and design procedures, low-cost satellite systems have specific requirements that enable them to be suitable for space applications. These necessary requirements include & #8230;
Less Mass and Power Consumption:
There is a great need for less mass and power consumption in the design of the low-cost satellite systems. The minimum mass usually contributes to a total mass reduction of the spacecraft that lessens the overall cost of the mission. Lessening or minimizing the power consumption is important in order to reduce additional need for solar cells, batteries, battery-charge regulators, and other power subsystems.
As previously mentioned, the complexity of the system forms a significant portion of a satellite communication subsystem. The development and implementation of low-cost satellites require the reduction of complexity in order to substantially decrease the overall cost of the mission. Increased spacecraft costs and assembly time are realized when extended tests are conducted to check the accurate connectivity and functioning of different subsystems. Moreover, lessening the overall costs of developing a satellite system can be achieved through the use of mass-produced miniature commercial motes that act as alternatives to the expensive custom space hardware.
This is particularly an important requirement for the development of long-distance deep space missions. In these kinds of satellite subsystems, it's necessary to test the radiation hardening of the electronic components (Lappas et. al., p.176).
The need for maximum performance of satellite systems has resulted in the design and development of miniature commercial off-the-shelf motes with enhanced data rates that the present Control Area Networks.
Maximum Reliability and Lifetime:
This is achieved through the use of a huge number of micro-sensors to result in a self-healing strong network. This kind of procedure enhances maximum reliability and lifetime unlike increasing the reliability of the network through enhanced redundancy.
Examples of Low-cost Satellite Subsystems:
There are various types of low-cost satellite subsystems that have been developed and used across different kinds of missions. Some of the major examples of these systems include & #8230;
The Cubesat subsystem is the most common type of low-cost satellite subsystems that has been developed in order to prove the practicability of a new series of standardized pico-satellites. These systems have also been developed to lessen the development time and minimize cost while providing enhanced access to space. The designers of these subsystems have the opportunity to form, develop, and test the functioning of their satellite communication system in space within an average time frame of the time of a college student. This is largely because the Cubesat low-cost satellite subsystems incorporate the use of simple standardized satellite geometry (Noe, p.5).
The Cubesat subsystem has emerged as the most common type of low-cost satellite subsystem because of its huge success to an extent that it has been launched in several countries such as Denmark, Canada, the United States, and Netherlands in the recent past. The success of this project or satellite system is attributed to its simple volume specifications and small mass. Actually, the specifications of these subsystems have established strict requirements on their mass and volume. To ensure that the project promotes effective communication, functions correctly, and fits properly, the established requirements on volume and mass are usually non-negotiable. In most cases, Cubesat satellite subsystems are not permitted to have over 1 kg of mass that include their electronics, structure, payload, and power.
The main concept in the development of these systems is to design or develop a generic opportunity for experimenting particular subsystems or components in space. In order to maintain reduced development time and low costs, Polysat satellites adheres to mass and size constraints. The main challenge handles by these types of satellites systems is offer a similar degree of qualification functionality and testing as a larger satellite system. The challenge is coupled by the need for the systems to achieve these goals within the size, power, and cost constraints that are similar to those of the Cubesat systems.
As an important aspect of these systems, communication with the earth-based communication station is through the use of a wide range of radio frequencies. This range of radio frequencies is determined by the requirements of data rate, the costs of earth station equipment, and licensing limitations. Notably, the systems use frequencies that are within the available amateur radio bands in order to handle licensing aspects and equipment cost.
KUTEsat subsystem is a low-cost satellite developed and evolving into the Kansas Universities Technology Evaluation Satellite. The system conducts preprogrammed measurements and experiments independently through a secondary communication system to the ground station while maintaining communication with the primary control module. The system has been developed with individual components that are locally controlled by microprocessors that communicate with the central control microprocessor in the control system. It provides modularized intelligence on the subsystem level that permits overall system sophistication while facilitating timely response to any system changes being developed (Marz, p. 24).
Implementation of Low-cost Satellite Subsystems:
Low-cost satellite subsystems have emerged as the most suitable alternative to larger systems to enhance satellite communications. The implementation of these systems is usually an important aspect that requires careful consideration to ensure that they function effectively and achieve their communication goals. In most cases, the implementation process of the systems have focused on several areas like communications subsystems, mission operations, data archival and dissemination, and control and data handling subsystem. Consequently, there is need for coordinated efforts in three main…