Satellites & Orbital Systems

In Philosophiæ Naturalis Principia Mathematica, Newton used the cannonball thought experiment to explain the motion of natural satellites. It constituted the first published mathematical treatment of the possibility of an artificial satellite, establishing the orbital mechanics underpinning all later orbital systems.

Hale's short story depicted an artificial satellite placed in orbit, the earliest fictional treatment of the idea. Jules Verne returned to the concept in The Begum's Fortune in 1879, seeding the notion in popular imagination.

Tsiolkovsky calculated the orbital speed required for a minimal orbit and inferred that a multi-stage rocket fuelled by liquid propellants could achieve it. He also first put forward the concept of geostationary satellites, establishing the theoretical basis for orbital systems.

Potočnik described using orbiting spacecraft for detailed peaceful and military observation of the Earth, and how space conditions could serve scientific experiments. The book covered geostationary satellites and radio communication with the ground, though it stopped short of mass broadcasting and telecoms relay concepts.

Clarke set out in detail the possible use of communications satellites for mass communications, proposing that three geostationary satellites would cover the entire planet. The article became the canonical conceptual foundation for the satellite communications industry.

The American theoretical astrophysicist set out the case for placing a telescope in orbit. The proposal anticipated the exploitation of outer space's near-perfect vacuum for observation across the electromagnetic spectrum.

The report argued that an instrumented satellite vehicle would be among the most potent scientific tools of the twentieth century. RAND framed the satellite as a tool for science, politics and propaganda rather than a military weapon; the US Navy's Bureau of Aeronautics had been considering orbital satellites since 1945.

R. R. Carhart's "Scientific Uses for a Satellite Vehicle" appeared in February 1954, followed in June 1955 by "The Scientific Use of an Artificial Satellite" by H. K. Kallmann and W. W. Kellogg. These reports expanded the catalogue of scientific missions satellites could perform.

The announcement of 29 July 1955 was framed around activities planned for the International Geophysical Year. Two days later the Soviet Union announced its own intention to launch a satellite by autumn 1957, setting up the race to orbit.

Launched on 4 October 1957 under the Sputnik programme with Sergei Korolev as chief designer, Sputnik 1 measured high atmospheric density through its orbital change and returned data on radio-signal propagation in the ionosphere. Its unanticipated success precipitated the Sputnik crisis in the United States and ignited the Space Race.

Launched on 3 November 1957, Sputnik 2 carried the dog Laika, sent without possibility of return. It demonstrated that living payloads could survive launch and orbital flight.

Following Project Orbiter's competing Army and Navy efforts, the Army's Jupiter C rocket placed Explorer 1 in orbit on 31 January 1958. Data from its radiation detector led to the discovery of the Earth's Van Allen radiation belts.

Launched on 1 April 1960 under the Television Infrared Observation Satellite programme, TIROS-1 sent back the first televised images of weather patterns taken from orbit. It established satellite meteorology as an operational capability.

The agencies aimed to send a wooden satellite prototype into orbit in summer 2024, after sending first wood samples to space in 2021 to test the material's resilience to space conditions. The project explores materials that would leave less residue on reentry.

The 2020 workshop report found that large satellite constellations can severely impair some astronomical research efforts and listed six mitigation measures. It framed the scientific case against unconstrained constellation growth.

Starlink passed a thousand operational spacecraft in 2020, with satellites designed to be 100% demisable and burn up completely on atmospheric reentry at end of life or early failure. Large constellations more than doubled the number of active satellites on orbit over five years.

On 27 March 2019 India destroyed a live satellite within three minutes of launch of the interceptor. It became the fourth country with a demonstrated capability to destroy live satellites.

On 18 November 2015, after two failed attempts, Russia successfully carried out a flight test of the Nudol anti-satellite missile. The test added Russia to the small group of states with demonstrated kinetic counter-space systems.

After the operational fielding of large satellite internet constellations, the companies building them began offering regular planned deorbiting of older satellites as part of obtaining launch licences. This embedded debris mitigation into the regulatory process for orbital systems.

The 2007 shoot-down demonstrated a kinetic anti-satellite capability against an orbiting target. The US Navy followed by shooting down a defunct spy satellite in February 2008.

With the advent of CubeSats and growing numbers of microsats launched to lower low Earth orbit altitudes, satellites were increasingly designed to break up and burn up entirely in the atmosphere. The shift was a response to accumulating debris and reentry risk.

From 1997 FreeFlyer was offered as a commercial application for satellite mission analysis, design and operations. Commercial tooling lowered the barrier to designing and operating spacecraft.

The HS-333 geosynchronous communications satellite introduced the practice of building multiple spacecraft on a single model platform. Standardised buses cut cost and development effort and became the industry norm.

On 26 November 1965 the A-1 satellite was placed in orbit by a Diamant A launched from the CIEES site at Hammaguir, Algeria. France thereby became the third country to launch a satellite on its own rocket and the sixth to own an artificial satellite.

The first Italian satellite was launched on 15 December 1964 on a US Scout rocket from Wallops Island, Virginia, by an Italian launch team trained by NASA. Like Canada's and Australia's firsts, it illustrated the pattern by which nearly all early national satellites reached orbit on foreign rockets.

By June 1961, three and a half years after Sputnik 1, the network had catalogued 115 objects in Earth orbit. The count marks the emergence of systematic space situational awareness.