The Top 10 Oldest Satellites in Orbit

Satellites are crucial to our daily lives, supporting everything from GPS navigation and telecommunications to weather monitoring and scientific exploration. But before today's advanced satellites and large mega-constellations, early satellites laid the foundation for all we understand about space-based technology. Launched during the Cold War and the early space race, many of these historic spacecraft are still quietly orbiting Earth decades later. They no longer operate, but their presence tells a story of ambition, innovation, and rapid progress in aerospace engineering. These orbiting relics are not just debris; they are remnants of humanity’s first steps into the cosmos. In this article, we examine the ten oldest satellites still in orbit, exploring their original missions, the legacy they leave behind, and the remarkable era they helped define.

1 Vanguard 1 

A model spacecraft with a spherical body and four extended antenna-like structures against a light blue background.

Vanguard 1 was the first satellite powered by solar cells and remains the oldest human-made object still in orbit. It provided vital data on Earth’s shape and upper atmospheric density, helping to confirm the planet’s equatorial bulge. Although it stopped communicating in 1964, its ongoing orbit provides a long-term benchmark for satellite design and orbital decay models.

SATCAT: 00005

Launch Date: 17 March 1958

Mission: Geodesy, Earth science, satellite technology demo

Status: Inactive

Last Contact: May 1964

Expected Decay Date: Around 2198

2 Vanguard 2

A model spacecraft with a spherical body and extended antenna-like structures

Vanguard 2 was the world’s first weather satellite, designed to measure cloud cover distribution with onboard optical scanners. Although its spin stabilization was misaligned, which limited scientific returns, it represented an early attempt to observe Earth's atmosphere from space. It remains a vital step in the development of operational meteorological satellites.

SATCAT: 00011

Launch Date: 17 February 1959

Mission: Meteorology; cloud cover observation

Status: Inactive

Last Contact: March 1959

Expected Decay Date: Circa 2260

3 Vanguard 3

A model spacecraft with a spherical body and four extended antenna-like structures

Vanguard 3 was designed to collect data on Earth's magnetic field and measure micrometeoroid impacts in space. Its successful mission contributed to our early understanding of space weather and orbital hazards. Although long silent, its continued presence in orbit provides historical insight into Cold War–era scientific priorities.

SATCAT: 00020

Launch Date: 18 September 1959

Mission: Magnetic field and micrometeoroid research

Status: Inactive

Last Contact: Not publicly recorded

Expected Decay Date: circa 2259

4 Explorer 7

A spacecraft or satellite with solar panels and an observation window floating in space against a black background.

Explorer 7 studied Earth’s radiation budget, solar X-rays, and cosmic rays. It was among the first satellites to monitor heat flow into and out of Earth’s atmosphere, a crucial factor in climate modelling. The data it collected contributed to foundational knowledge in Earth science and the effects of solar radiation on weather.

SATCAT: 00022

Launch Date: 13 October 1959

Mission: Climate and solar radiation studies

Status: Inactive

Last Contact: 24 August 1961

Expected Decay Date: Unknown

5 Pioneer 5

Black and white image of a satellite with four solar panels, inside a space module with metallic walls.

Pioneer 5 was launched into a solar orbit to explore the space between Earth and Venus. It measured the interplanetary magnetic field and solar radiation at a then-record distance for radio communication. Although contact was lost within months, it laid the groundwork for deep-space exploration and set milestones in data transmission from space.

SATCAT: 00027

Launch Date: 11 March 1960

Mission: Interplanetary space physics

Status: Inactive (heliocentric orbit)

Last Contact: June 1960

Expected Decay Date: N/A (orbiting the Sun)

6 TIROS 1

Three men working on spacecraft component inside a hangar or workshop.

TIROS 1 (Television Infrared Observation Satellite) was the first satellite to send real-time cloud imagery from space, demonstrating that satellites could revolutionise meteorology. It transmitted over 22,000 images during its brief lifespan and directly contributed to the development of today’s global satellite weather systems, transforming how we forecast storms and climate patterns.

SATCAT: 00029

Launch Date: 1 April 1960

Mission: Experimental weather observation

Status: Inactive

Last Contact: 15 June 1960

Expected Decay Date: Unknown

7 Transit 2A

Black and white image of a spacecraft module with astronauts in suits working around it.

Transit 2A was part of the U.S. Navy’s first satellite navigation system, enabling precise positioning through Doppler shifts from orbiting satellites. Although basic by today’s standards, it served as a direct precursor to modern GPS. It demonstrated the feasibility of space-based navigation for submarines, ships, and future civilian uses.

SATCAT: 00045

Launch Date: 22 June 1960

Mission: Satellite navigation system testing

Status: Inactive

Last Contact: Circa 1961

Expected Decay Date: Unknown

8 SOLRAD 1

Close-up of a metallic space capsule with solar panels and antennas against a blue sky background.

SOLRAD 1 was the first satellite to perform dual missions—scientific and intelligence-gathering. It measured solar X-rays while covertly intercepting Soviet radar emissions for the U.S. Navy. It marked the start of space-based signals intelligence and was a pioneer of today’s classified reconnaissance satellites.

SATCAT: 00046

Launch Date: 22 June 1960

Mission: Solar observation and electronic surveillance

Status: Inactive

Last Contact: April 1961 (science), September 1960 (ELINT)

Expected Decay Date: Unknown

9 Courier 1B

A man with glasses and a checkered jacket works on a spherical structure covered in solar panels, likely a model or prototype of a spacecraft or satellite.

Courier 1B was the world’s first active repeater communications satellite. It could store and forward messages—a key innovation for early space communications. Although it operated for only a few weeks, it paved the way for future military and commercial communication satellite systems by demonstrating real-time digital signal transmission.

SATCAT: 00058

Launch Date: 4 October 1960

Mission: Communications relay test

Status: Inactive

Last Contact: 21 October 1960

Expected Decay Date: Unknown

10 Venera 1

Spacecraft or satellite with large solar panels on either side, displayed indoors.

Venera 1 was the first spacecraft launched with the goal of reaching another planet—Venus. Although communication was lost before its planned flyby, it was the first probe to enter heliocentric orbit after launch and marked a major milestone in Soviet deep-space ambitions. It paved the way for future Venera missions, many of which successfully reached Venus.

SATCAT: 00080

Launch Date: 12 February 1961

Mission: Venus flyby probe

Status: Inactive (heliocentric orbit)

Last Contact: 19 February 1961

Expected Decay Date: N/A (solar orbit)