From Sputnik to Firefly: The Fascinating World of Satellites
September 14, 2023
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By
Amy Zammit and Pradyumna Bang
October 4, 1957 - “T -10 minutes,” blared the loudspeaker in an underground bunker in the Baikonur Cosmodrome, Kazakhstan. Just 200 meters away, the Tulip launch pad hosted a colossal 29-meter R-7 rocket with a unique payload: a shiny, sphere, basketball-sized sphere, weighing 83.6 kg.
Sputnik satellite, shown resting on a three-legged pedestal in 1957 (Russian News Agency, via New York Times)
Sputnik-1, the world’s first artificial satellite, marked a monumental milestone, inaugurating the Space Age and triggering the Space Race. Sputnik’s characteristic radio signals were a symbol of Soviet technological prowess, revolutionizing the era of space exploration.
From Sputnik to today’s technological marvels, the satellite journey is captivating, evolving from its humble beginnings to redefining our understanding of our planet.
What is a satellite?
A satellite is something that orbits a planet or star, including natural satellites (like our Moon) and artificial satellites.
Artificial satellites are man-made objects, typically built for Earth’s orbit but can serve missions on other planets, such as the Mars Orbiter Mission (MOM). They’re built, launched, and operated for objectives like imaging, communications, and scientific research.
Explained: A brief history of satellites
How did the concept of satellites emerge? What experiments caused us to get to where we are today?
Page extract from Newton’s ‘A Treatise of the System of the World’ which shows his cannonball experiment (Google Books, via Wired).
Newton theorised that launching a cannonball at various speeds would yield different outcomes: low speeds (between 0 and 7,000m/s) would lead to it falling to Earth, moderate speeds (between 7,000 and 10,000 m/s) would create an elliptical orbit around our planet, and speeds exceeding 10,000 m/s (or Earth’s escape velocity) would allow escape from Earth’s gravitational pull. This laid the foundation for artificial satellites.
Newton’s cannonball thought experiment with an initial velocity under 7,300 m/s (top) and between 7,300 and 10,000 m/s (bottom) (Wikimedia Commons).
2. Tsilovsky’s influence: the Father of Spaceflight
Konstantin Tsiolkovsky, a Russian (and later Soviet) scientist, is celebrated as the “Father of Spaceflight.” His ideas set the stage for space exploration and modern rocket development.
In 1903, he outlined the principles of rocket propulsion and space travel. Tsiolkovsky’s most notable contribution was the concept of multi-stage rockets for launching payloads into Earth’s orbit.
3. Clarke’s vision and the modern satellite era
In the mid-20th century, science fiction writer Arthur C. Clarke played a crucial role in revolutionising telecommunications. His 1945 piece, “Extraterrestrial Relays,” laid the groundwork for the modern satellite era.
Clarke’s theory proposed that a satellite orbiting at Earth’s rotational speed would remain fixed relative to the planet’s surface. Positioned about 35,786 kilometres above Earth, this seemingly stationary satellite would serve as a relay for telecommunication signals, revolutionising how we connect.
What does a satellite consist of?
A typical satellite consists of electrical, mechanical, and chemical components which perform specific functions within the satellite. These can be divided into satellite subsystems:
Electrical and Electronics Subsystem: - Power subsystem: Supplies energy, typically from solar panels, crucial for all other subsystems. - Communication subsystem: Facilitates data transmission via antennas, enabling information transfer between the satellite and Earth.
Thermal Control Subsystem: Regulates satellite temperature with heaters and radiators to prevent component damage due to extreme temperature changes.
Structural Subsystem: Ensures structural integrity, enabling the satellite to withstand launch and operational forces, including its frame and supports.
Mission Planning and Dynamics (MPD): Involves precise orbit planning, movement prediction, and control to optimise satellite performance in achieving its objectives efficiently and effectively.
2018: SpaceX’s Falcon Heavy rocket, carrying a Tesla Roadster payload, was successfully placed into sun-centered orbit.
Some notable satellites and their breakthrough
TheCORONA program, active from 1959 to 1972, operated secret reconnaissance satellites with high-resolution camera systems to surveil the Soviet Union during the Cold War. Capsules with photos were parachuted and collected mid-air. The program was highly classified, so information was only publically acknowledged in the 1990s.
Voyager 1, a space probe launched by NASA in 1977, explores the outer Solar System and beyond. It’s been in space for over 40 years, making it the farthest man-made object from Earth. Voyager 1 carries a ‘Golden Record’ with a collection of Earth’s sounds and images, serving as a message to potential extraterrestrial lifeforms that may encounter the spacecraft.
Engineers working on NASA’s Voyager in 1976 (NASA).
The Hubble Space Telescope, named after astronomer Edwin Hubble, was launched in 1990 by NASA and the European Space Agency (ESA). With a 2.4-meter primary mirror, it is situated in a low Earth orbit, capturing extremely detailed celestial images and revolutionising astronomy (for example, leading to the discovery of dark energy). Though it initially suffered from a flawed primary mirror which caused blurry images, astronauts corrected it during a 1993 repair mission, allowing the Hubble to produce breathtaking images, like the Hubble Ultra-Deep Field revealing thousands of galaxies in a small portion of the sky.
Annotated version of the Hubble Ultra Deep Field (NASA Hubble site).
Cassini, launched in 1997 to explore Saturn and its moons, discovered new moons and conducted flybys (notably of Titan). The mission ended in 2017 as Cassini descended into Saturn’s atmosphere. The data from Cassini’s mission yielded vital insights into Saturn’s system, including the possibility of life on its moons.
An artistic interpretation of Cassini’s Saturnian mission (NASA/JPL).
The James Webb Space Telescope (JWST), launched in 2021 by NASA, ESA, and the Canadian Space Agency succeeds the Hubble Telescope’s mission to observe early galaxies and analyze exoplanet atmospheres. Positioned at the second Lagrange point (L2), about 1.5 million kilometres from Earth, JWST boasts a 6.5-metre primary mirror.
Artistic interpretation of the James Webb Space Telescope (NASA, via Science News).
A New Satellite Era: Pixxel’s hyperspectral imaging satellites
As we celebrate the incredible journey of satellites, from their early conceptualisation to their monumental achievements, we welcome a new era of satellite technology. Hyperspectral imaging, exemplified by Pixxel's upcoming hyperspectral satellite constellation launching in 2024, promises unprecedented insights into our planet.
With high spatial and spectral capabilities, this technology will transform agriculture, environmental monitoring, resource exploration, and more. Tomorrow’s satellites will continue pushing boundaries, enriching our understanding of Earth and the universe.
Reach out to our sales team to explore how hyperspectral imaging satellites can transform your organisation.
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