The commercial applications of satellites and satellite technologies are rapidly developing and are projected to continue developing. There are some potential problems that could occur with more satellites in orbit, like space debris, overcrowding and hindering optical astronomy. Some companies are already working on solutions to these problems and the benefits are carefully weighed before setting the satellites in orbit. The paper analyzes three programs that are currently in place and are continuing their development: IKONOS satellites, SpaceX’s Starlink satellites and Landsat satellites. Each of these programs contribute something different to the world. Because of this, they are individually evaluated to provide insight to the future of commercial satellites and satellite technologies.
Keywords: Commercial, IKONOS, Landsat, Satellites, SpaceX, Starlink.
Satellite technology is rapidly developing across the board, but none more so than in their commercial applications. Companies are now capable of sending satellites into low earth orbit (LEO) to perform actions that would have historically been impossible. Some examples of this are global internet services and high resolution imagery of the Earth’s surface. Even if a company is not capable of launching their own satellites, they can obtain information off of other companies and organizations satellites, such as the National Aeronautics and Space Administration’s (NASA) Land, Atmosphere Near real-time Capability for Earth Observing System (LANCE) interface.
Development of Satellite Technology
Satellites, and space exploration in general, started with Sputnik 1 in 1957. It was just a metal ball with a thermometer, battery and radio inside of it (Dunbar, 2015). Since then satellites have developed into three main categories: security and defense, scientific study, and commercial applications. Nowadays each company’s use of satellites is determined by their specific mission. Within them they can have a vast amount of instruments that can do anything from determining the composition of another planet’s atmosphere to providing internet services to the world.
Commercial Applications of Satellites
Satellites have become an investment for many businesses to do work that would be harder to do or impossible to do otherwise. The imagination is truly the limit when it comes to satellite innovations. Some companies have put satellites in orbit to produce data and have then use it for a multitude of applications. A great example of this is the Landsat satellite (further described below). The company regularly puts satellites in orbit to obtain precise data, they then provide the data to companies and agencies for security and defense, scientific study and they also sell it for commercial applications.
The Future of Commercial Satellites
In the future, satellites will be able to provide services to people that cannot currently get them. The Starlink satellites by SpaceX (further described below) is a great example of this in development now. The end goal of this program is to provide internet service to the world through their complex satellite constellation of up to 12,000 satellites (Burleigh, De Cola, Morosi, Jayousi, Cianca & Fuchs, 2019). Normally, internet service distribution is hindered by location, money and basic development problems, but not if the provider is in orbit.
Potential Problems
The growing demand for satellites in orbit has a couple of potential problems. The first is overcrowding and debris, especially in LEO. The second potential problem is cluttering the skies and making it more difficult to perform optical astronomy. As the satellite industry continues to develop, more problems will arise that need to be fixed.
IKONOS Satellite
Lockheed Martin and Raytheon was contracted by Space Imaging to create the space and ground segments of the Commercial Remote Sensing Satellite (CRSS), which is now known as IKONOS (Dial, Bowen, Gerlach, Grodecki, & Oleszczuk, 2003). IKONOS is known to be the first commercial satellite with high-resolution imagery exceeding 1-meter resolution (Apollo Mapping, 2020). It was the most agile satellite in orbit from 1999 until 2007, and it was decommissioned in 2014 (Apollo Mapping, 2020).
IKONOS Specifications
IKONOS was launched out of California in 1999 via an Athena 2 vehicle (Apollo Mapping, 2020). It is currently in orbit with the following characteristics: 681-kilometer attitude, 98 minutes period, 7.5 kilometer per second orbit speed, 6.8 kilometer per second over ground speed, 98.1-degree inclination (Apollo Mapping, 2020). The orbit is north to south with a total of 14 minutes spent on the lit side of the Earth (Apollo Mapping, 2020).
Instruments and Functionality
There are four reaction wheels for actuators and two-star trackers and a sun sensor for attitude measurement to serve as its control systems (Apollo Mapping, 2020). Its ground communications consist of 320 megabits per second imagery downlink, up to 256 kilobytes per second maintenance and metadata downlink and 2 kilobytes per second tasking and commands uplink (Apollo Mapping, 2020). For its optical sensor, there is a 70-centimeter diameter primary mirror, which includes a 10-meter focal length and 70-centimeter aperture (Apollo Mapping, 2020).
SpaceX’s Starlink Satellites
Starlink is a SpaceX initiative to bring high speed internet to the entire world. The Starlink constellation is proposed to have 12,000 satellites, which contributes to why it is one of the biggest advancements to satellite production ever (Burleigh, De Cola, Morosi, Jayousi, Cianca & Fuchs, 2019). This doesn’t come without complications. There is concern about space debris and orbital plans with these satellites.
Orbital Plans
The main concern with Starlink is the fact that there are so many of them proposed to be in orbit that they pose a conflict with other satellites and they will produce LEO debris. According to the starlink.com website, the satellites will be placed in orbit around 550 kilometers, when the average satellite is 1,000 or more kilometers (SpaceX, 2020). This also contributes to the plan for getting rid of space debris. At the end of the satellites life it will use its propulsion to deorbit and burn up in the Earth’s atmosphere (SpaceX, 2020). If the propulsion system fails, then the satellites orbit is so close to Earth that they will burn up in 1-5 years anyways (SpaceX, 2020).
Instruments and Functionality
Starlink satellites are designed based on SpaceX’s the need to launch an enormous amount of them into orbit. They weigh in at approximately 575 pounds apiece, but they are flat and compact to be able to fit many of them in the Falcon 9 rockets (SpaceX, 2020). They consist of 4 array antennas, a single solar array, and a krypton propelled ion propulsion system (SpaceX, 2020). They also have navigational sensors on board to measure the satellites attitude (SpaceX, 2020). Finally, SpaceX utilized an orbital debris tracking system to independently maneuver the satellite to avoid collision with other objects in orbit (SpaceX, 2020).
Landsat Satellites
Landsat is a satellite program developed by NASA and the U.S. Geological Survey (USGS) to “provide essential land change data and trending information not otherwise available” (USGS, 2020). Starting off as a government-based program in 1972 with Landsat 1 and developing into commercial applications with people around the world using the data for “research, business, education and other activities” (USGS, 2020). Since Landsat 1, there have been seven more launches with Landsat 7 and 8 currently in orbit (USGS, 2020). Landsat 9 is currently being developed and is set to launch in 2021 (USGS, 2020).
Orbital Plans
The key to a successful orbit with Landsat is for it be on the lit side of the Earth for as much time as possible to be able to collect picture data. Each satellite is placed at an altitude of about 570 miles at 99-degree inclination and a “sun-synchronous orbit” (Masek, 2020). A sun-synchronous orbit means that it orbits at the same rate that the Earth spins. This orbit is optimal because it allows the most time on the lit side of the earth which puts it on the Equator about 9:30 to 10 am every day (Masek, 2020).
Instruments and Functionality
Each satellite has been able to outperform the last with its technology, so Landsat 8 will have the latest technology until 9 is finalized. Landsat 8 was developed by NASA and the Department of Interior USGS and is designed to last 5 years and to use the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS) (Irons, Dwyer & Barsi, 2012). Ball Aerospace and Technologies Corporation built the OLI, which is a sensor with a four-mirror telescope and a 12-bit quantization (USGS, 2020). OLI is used to collect data for visible, near infrared, and short-wave infrared images (USGS, 2020). The TIRS was built by NASA to enable thermal imagining and to measure evapotranspiration rates (USGS, 2020). This sensor has an estimated 3-year life span and can combine with the “OLI data to create radiometrically, geometrically, and terrain corrected” products (USGS, 2020). Landsat 9 have the same two types of instruments on board only upgraded to a second version, OLI-2 and TIRS-2. The new satellite will replace the old one as it reaches the end of its 5 year life span with only one big upgrade. The TIRS-1 had an issue with light pollution that reduced the accuracy of thermal measurements, TIRS-2 fixed this problem (USGS, 2020).
Conclusion
The commercial application of satellites is growing just as rapidly as the rest of the booming satellite categories. With the potential advancements in the technology giving the ability for innovation and advancement of industries and the world as a whole. Though the industry will continue to advance, problems will arise and will need to fix. Just like how SpaceX solved their problem of LEO debris, other companies will need to evaluate their contributions to the problems and fix them. So even with the potential problems, programs like IKONOS, Starlink and Landsat will grow and more will be developed like them.
References
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Burleigh, S., De Cola, T., Morosi, S., Jayousi, S., Cianca, E., & Fuchs, C. (2019). From Connectivity to Advanced Internet Services: A Comprehensive Review of Small Satellites Communications and Networks. Wireless Communications and Mobile Computing, 2019, 1–17. https://doi.org/10.1155/2019/6243505
Dial, G., Bowen, H., Gerlach, F., Grodecki, J., & Oleszczuk, R. (2003). IKONOS satellite, imagery, and products. Remote Sensing of Environment, 88(1), 23–36. https://doi.org/10.1016/j.rse.2003.08.014
Dunbar, B. (2015, March 18). The Early Satellites. Retrieved October 17, 2020, from https://www.nasa.gov/missions/science/f-satellites.html
Irons, J., Dwyer, J., & Barsi, J. (2012). The next Landsat satellite: The Landsat Data Continuity Mission. Remote Sensing of Environment, 122, 11–21. https://doi.org/10.1016/j.rse.2011.08.026
Masek, J. (2020, October 8). Landsat Spacecraft Orbit " Landsat Science. Retrieved October 17, 2020, from https://landsat.gsfc.nasa.gov/landsat-spacecraft-orbit/
SpaceX. (2020). Starlink. Retrieved October 17, 2020, from https://www.starlink.com/
US Geological Survey (USGS). (2020). What Is The Landsat Program And Why Is It Important? Retrieved October 17, 2020, from https://www.usgs.gov/faqs/what-landsat-satellite-program-and-why-it-important?qt-news_science_products=0
