In the context of space technology, the earth has significantly benefited from a lot of innovations and advancements related to space, particularly in terms of communications, positioning based on products or services, earth observation based on gathering data about Earth’s physical, chemical, and biological systems using remote sensing technologies, and commercial space activity such as direct-to-home satellite television (DirecTV and DishTV), satellite radio (Sirius XM), and commercial communications satellites that transmit voice, data and Internet services (such as Intelsat Ltd., SES Global, and Eutelsat).
Since the launch of Sputnik in 1957, humankind's capacity for space exploration has greatly increased. Over 8,100 space objects have been launched since then, including numerous exploration missions to every corner of the solar system, 135 Space Shuttle flights, the building of the International Space Station (ISS) and human landings on the moon.
Applications of scientific knowledge that are utilized in space to impact our daily lives are included in space technology.
In March, the US announced that it would send astronauts to the Moon permanently in 2024. Many other nations have expressed their desire to reach the Moon. With the explosion of more than 2,000 commercial space companies, including those creating communications satellites, orbital launch vehicles, lunar and mars rovers, orbital space habitats, space manufacturing platforms and space greenhouses, the capacity of commercial space in nations around the world is rapidly expanding beyond the satellite industry, which has already generated more than $277 billion in global revenues over the past year. Despite the pandemic, a record number of satellites were deployed into orbit in 2021, which also saw a 44% increase in commercially purchased satellites compared to the previous year.
Although some people remain uncertain about the future of space technology, lamenting the planet’s increased potential for self-destruction, space technologies have not only enormously benefited many areas of life but have also deepened our understanding as to the true nature of humanity.
Widespread Use of Small Satellites
When defining small satellites, aka miniaturized satellites, we are typically referring to those under 1200 kg. While all of these satellites can be categorized as "small," different classifications are used to group them further based on mass.
These include minisatellites, microsatellites, nanosatellites, picosatellites, and femtosatellites and are divided according to weight. Commercial companies, nonprofit organizations and educational institutions can conduct their missions in the lower Earth orbit using these small satellites because they are an affordable alternative.
The widespread use of small satellites for communication and navigation is the result of rising demand for cutting-edge technologies like over-the-top (OTT) services and Internet Protocol Television (IPTV). Such deployment is boosting the global market as well.
Furthermore, the growing global small satellite market also influences the enormous and growing demand for earth observation and remote sensing services across many sectors, including energy, oil and gas, defense and agriculture.
Opportunities Originating from Small Satellites
Broadly speaking, small satellites are consistently positioned in lower orbits, thus decreasing signal attenuation between the satellite and the ground. Compared to a satellite at 850 km, communication with a satellite at 500 km requires nearly a third of the transmission power.
Moreover, small satellite constellations — a group of artificial satellites working together as a system — can access potentially higher resolution for site-specific software. Because of the presence of clouds, analysis of high temporal resolution optical imagery is often constrained. Some of these issues have been resolved by the creation of temporal gap-filling techniques as well as the combination of Copernicus optical and radar products.
Furthermore, given the fact that there are more sensors available on small satellites, they may also be able to gather data across more spectral bands. In the case of mapping plant species and plant diversity from space, for instance, it is possible to track invasive species using the data gathered by hyperspectral imaging sensors. Only a small number of missions, like PRISMA, currently have access to hyperspectral data. Therefore, the creation of small satellite constellations with hyperspectral sensors would significantly enhance our capacity to track how environmental change affects biodiversity and the delivery of ecosystem services.
While there are continuing challenges in space exploration, including those specific to small satellites, opportunities abound. To date, seizing such opportunities has been the purview of a few, but this is slowly changing. Traditionally, national agencies that had sufficient manpower and finances pioneered space efforts. The same can apply to the maximization of small satellite opportunities.
Focus of Upcoming Research
A mission architecture consisting of a large number of satellites is called a distributed satellite system. The mission planning of a large-scale, distributed satellite system offers improved real-time, continuous global coverage and greater flexibility compared to that of a single satellite. In the aerospace industry, large, expensive satellites are steadily being replaced by small, affordable, mass-produced versions. For example, the SpaceX project helmed in the United States aims to put about 12,000 satellites into orbit between 2019 and 2024, of which 1,584 will be placed in Low-Earth orbit, 550 kilometers above Earth. The sheer scale of satellite systems presents a new set of major challenges to mission planning for the entire system. Large restrictions make it difficult to accurately utilize traditional programming models The algorithm's size, execution time and solution efficiency all increase due to the exponential growth of data. Therefore, the challenge ahead is to determine how to plan missions for large, distributed satellite systems.
Moreover, the majority of satellites currently in use receive mission planning from the ground and are only able to carry out the task instructions that have been uploaded from Earth during their deployment. The actual operation of the satellite will, however, face a number of unknown issues. Weather changes, for instance, can have a significant effect on the function of the optical reconnaissance satellite. If it carries out a fixed task while being obstructed by clouds, it will fail to complete the objective and use up observational resources in the attempt. If a satellite component fails while it’s in operation, the load interruption will not necessarily affect satellite operation but may alter the satellite’s earth observation, and the mission will still fail due to the limits of the original mission instructions.
Small satellites are currently altering the economics of space. These spacecraft utilize cutting-edge commercial off-the-shelf (COTS) technology, enabling creative and less expensive methods to carry out valuable observational missions.
Synthetic aperture radar (SAR) is a technique for extracting high-resolution images from a resolution-limited radar system, and hyperspectral imaging missions on minisatellites are currently in planning and will soon be fully operational. The thermal stability of the imaging instrument, which is necessary to produce sharp imagery, can be a significant obstacle for high-resolution imaging missions or for hyperspectral missions on small spacecraft. Technologies like SAR aim to surmount such limitations.
Small satellites will undoubtedly be a part of the future remote sensing conservation toolbox. When teamed with current commercial and civilian programs, such satellites could increase data resolution and accessibility, significantly enhancing the precision and power of monitoring wildlife and natural resources. However, sufficient regulatory frameworks, related systems and technologies must be "in place" before the application of this technology really takes off. Only then can ecologists maximize its true potential.
