The Gravity Gradient Stabilization Experiment (GGSE-4) was a technology satellite launched in 1967. This was ostensibly the fourth in a series that developed designs and deployment techniques later applied to the NOSS/Whitecloud reconnaissance satellites.
GGSE-4 was launched by the U.S. Airforce from Vandenberg Air Force Base atop a Thor Agena-D rocket. [1] GGSE-4 remained operational from 1967 through 1972. [2]
It is alleged that the real name of GGSE-4 was POPPY 5B or POPPY 5b and that it was a U.S. National Reconnaissance Office satellite designed to collect signals intelligence; [3] POPPY 5B was part of a 7-satellite mission. A partial subset of information about POPPY was declassified in 2005. [4]
Other sources say that GGSE-4 weighed only 10 pounds but that it was attached to the much larger Poppy 5, which would have weighed 85 kg and featured an 18-meter boom. [5] It is further alleged that GGSE-4's mass is not at all like GGSE-1's mass and that GGSE'4 weighs 85 kg. [6]
On 29 January 2020, 23:39:35 UTC, [7] GGSE-4 was expected to pass as closely as 12 meters [8] from IRAS, another un-deorbited satellite left aloft. IRAS was launched in 1983 and abandoned after a 10-month mission. The 14.7-kilometer per second pass [9] had an estimated risk of collision of 5%. Further complications arose from the fact that GGSE-4 was outfitted with an 18 meter long stabilization boom that was in an unknown orientation and may have struck the satellite even if the spacecraft's main body did not. [10] Initial observations from amateur astronomers seemed to indicate that both satellites had survived the pass, with the California-based debris tracking organization LeoLabs later confirming that they had detected no new tracked debris following the incident. [11]
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, peaking in number at an altitude around 800 km (500 mi), while the farthest in LEO, before medium Earth orbit (MEO), have an altitude more than about one-third of the radius of Earth, roughly at the beginning of the inner Van Allen radiation belt.
Space debris are defunct human-made objects in space – principally in Earth orbit – which no longer serve a useful function. These include derelict spacecraft, mission-related debris, and particularly-numerous in-Earth orbit, fragmentation debris from the breakup of derelict rocket bodies and spacecraft. In addition to derelict human-made objects left in orbit, space debris includes fragments from disintegration, erosion, or collisions; solidified liquids expelled from spacecraft; unburned particles from solid rocket motors; and even paint flecks. Space debris represents a risk to spacecraft.
The Infrared Astronomical Satellite (IRAS) was the first space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten months. The telescope was a joint project of the United States (NASA), the Netherlands (NIVR), and the United Kingdom (SERC). Over 250,000 infrared sources were observed at 12, 25, 60, and 100 micrometer wavelengths.
Gravity-gradient stabilization or tidal stabilization is a passive method of stabilizing artificial satellites or space tethers in a fixed orientation using only the mass distribution of the orbited body and the gravitational field. The main advantage over using active stabilization with propellants, gyroscopes or reaction wheels is the low use of power and resources. It can also reduce or prevent the risk of propellant contamination of sensitive components.
Long March 5, or Changzheng 5 (CZ-5), and also by its nickname "Pang-Wu", is a Chinese heavy-lift launch vehicle developed by the China Academy of Launch Vehicle Technology (CALT). It is the first Chinese launch vehicle designed to use exclusively non-hypergolic liquid propellants. It is the fifth iteration of the Long March rocket family.
The Kessler syndrome, proposed by NASA scientists Donald J. Kessler and Burton G. Cour-Palais in 1978, is a scenario in which the density of objects in low Earth orbit (LEO) due to space pollution is numerous enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. In 2009, Kessler wrote that modeling results had concluded that the debris environment was already unstable, "such that any attempt to achieve a growth-free small debris environment by eliminating sources of past debris will likely fail because fragments from future collisions will be generated faster than atmospheric drag will remove them". One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges difficult for many generations.
In 2015, the maiden spaceflights of the Chinese Long March 6 and Long March 11 launch vehicles took place.
Several new rockets and spaceports began operations in 2016.
Tianhe, officially the Tianhe core module, is the first module to launch of the Tiangong space station. It was launched into orbit on 29 April 2021, as the first launch of the final phase of Tiangong program, part of the China Manned Space Program.
Resurs-P No.1 was a Russian commercial Earth observation satellite capable of acquiring high-resolution imagery. It is one of a series of Resurs-P spacecraft. The spacecraft was operated by Roscosmos as a replacement of the Resurs-DK No.1 satellite until it ceased operations in 2021. In 2024 the satellite broke up, releasing objects into low earth orbit which required the crew of the ISS to take shelter.
Kosmos 2499 was a Russian satellite orbiting the Earth, before breaking up on January 4, 2023.
ATS-4 also known as ATS-D was a communications satellite launched by NASA on August 10, 1968 from Cape Canaveral through an Atlas-Centaur (AC-17) rocket.
ÑuSat satellite series, is a series of Argentinean commercial Earth observation satellites. They form the Aleph-1 constellation, which is designed, built and operated by Satellogic.
The Gravity Gradient Stabilization Experiment (GGSE-1) was a technology satellite launched simultaneously with four other satellites on 11 January 1964 by the U.S. military from Vandenberg Air Force Base aboard a Thor Augmented Delta-Agena D rocket. It demonstrated a new oscillation damping system intended for use in reconnaissance satellites.
Space sustainability aims to maintain the safety and health of the space environment.