Every time we look up at the skies, we’ll likely not see any of these objects. But beyond the reach of our eyes lies more than 23,000 or so catalogued objects currently in orbit around the Earth. While more than 2,000 of these are active satellites, the rest could be anything from spacecraft and satellites, to even rocket stages that have been discarded and hardware that is now fragmented.
It comes down to space debris analysts to keep a tab of these, helping ensure that none of this space junk jeopardises those that are operational. Among all the objects in orbit owing to more than 65 years of space exploration, there is one in particular that is of interest. This object, now known as 1958-002B, is more popularly known by its original name, Vanguard 1.
Grapefruit-sized satellite
Launched on March 17, 1958, this grapefruit-sized shiny metal sphere is now the oldest human-made object still in orbit. Placed in a high elliptical orbit, it is still there, hovering between 650 and 3,800 km from the Earth. The second successful satellite launched by the U.S., it is also the Earth’s longest-orbiting artificial satellite now.
Vanguard was set to be America’s first satellite programme when it was conceived in 1955 by the Naval Research Laboratory (NRL). With the Vanguard system including a three-stage rocket, it was designed to launch a civilian scientific spacecraft. Together with an ambitious network of tracking stations, the rocket and satellite were to form part of the U.S.’ contribution to the 1957-58 International Geophysical Year.
Sputnik shock
But when the Soviet Union launched Sputnik 1 on October 4, 1957, the U.S. were jerked into action. With Sputnik 2 being launched in November, the Soviet Union had two satellites successfully launched into orbit.
This meant that what was initially planned as an incremental test of Vanguard’s Test Vehicle 3 (TV3) on December 6 now became a public event. The Vanguard rocket lifted off, only to crash back to the ground in flames. While the Soviets had achieved their success in secrecy before announcing it, the Americans failed publicly and were humiliated.
Explorer 1
To address this, they turned to German-American rocket pioneer Wernher von Braun, who grabbed the opportunity. One of von Braun’s Jupiter launchers were put to use on January 31, 1958 to launch Explorer 1 – America’s first successful satellite. Designed and built by the Jet Propulsion Laboratory in just three months, Explorer 1’s cosmic ray detector – designed by American space scientist James Van Allen – revealed the Van Allen Belts.
This meant that the Navy had to wait until March 17 for their turn. NRL’s Vanguard rocket carried Vanguard 1 – the first solar-powered spacecraft – into orbit around Earth. Weighing just 1.5kg and stretching 16.5cm across, Vanguard 1 is less than the size of a basketball and even led Soviet leader Nikita Khrushchev to call it as “the grapefruit satellite.”
An illustration of Vanguard 1 in space. | Photo Credit: photo: turkeychik / FLICKR
As it was powered by six matchbox-sized solar panels, it was able to transmit data until 1964. It was able to show how the Earth bulges around the equator, in addition to proving the technologies involved – be it the launcher system, ground station network and solar cells.
Distant, long-term orbit
While Sputnik 1 and 2 were sent on smaller rockets and hence fell back to the Earth in the first year itself, Explorer 1 returned to Earth after 12 years. As Vanguard 1 employed a three-stage rocket, it was injected into a 654 x 3969 km, 134.27 minute orbit inclined at 34.25 degrees – a distant, long-term orbit.
This orbit led scientists to place an initial lifetime estimate of 2,000 years! Soon, however, it was discovered that solar radiation pressure and atmospheric drag with high levels of solar activity led to significant perturbations in the perigee height of the satellite. As a result, the expected orbital lifespan of the satellite had to be trimmed largely, bringing it to about 240 years.
This means that more than 65 years after it was launched, this small satellite is still in orbit around the Earth, making it the oldest such object. Having spent just over a quarter of its lifespan until now, Vanguard 1 will still be orbiting Earth more than another 150 years from now.
