J002E3 is an object in space discovered on September 3, 2002, by amateur astronomer Bill Yeung. Initially thought to be an asteroid, it has since been tentatively identified as the

S-IVB The S-IVB (pronounced "S-four-B") was the third stage on the Saturn V and second stage on the Saturn IB launch vehicles. Built by the Douglas Aircraft Company, it had one J-2 rocket engine. For lunar missions it was fired twice: first for Earth ...

third

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

of the Apollo 12

Saturn V Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, with three stages, and powered with liquid fuel. It was flown from 196 ...

rocket (designated S-IVB-507), based on spectrographic evidence consistent with the

titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insolub ...

in the paint used on the rockets. The stage was intended to be injected into a permanent heliocentric orbit in November 1969, but is now believed instead to have gone into an unstable high Earth orbit which left Earth's proximity in 1971 and again in June 2003, with an approximately 40-year cycle between heliocentric and

geocentric orbit A geocentric orbit or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debri ...

Discovery

When it was first discovered, it was quickly found that the object was in an

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

around

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

. Astronomers were surprised at this, as the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

is the only large object in orbit around the Earth,Also orbiting the Earth are the

Kordylewski cloud Kordylewski clouds are large concentrations of dust that exist at the and Lagrangian points of the Earth–Moon system. They were first reported by Polish astronomer Kazimierz Kordylewski in the 1960s, and confirmed to exist in October 2018. Di ...

s: large transient concentrations of dust at the Trojan points of the Earth–Moon system, discovered in 1956 by the

Polish Polish may refer to: * Anything from or related to Poland, a country in Europe * Polish language * Poles Poles,, ; singular masculine: ''Polak'', singular feminine: ''Polka'' or Polish people, are a West Slavic nation and ethnic group, w ...

astronomer

Kazimierz Kordylewski Kazimierz Kordylewski (born 11 October 1903 in Poznań – 11 March 1981 in Kraków, Poland) was a Polish astronomer. In 1956, he claimed the discovery of the Kordylewski clouds, large transient concentrations of dust at the Trojan points of th ...

. and anything else would have been ejected long ago due to

perturbation Perturbation or perturb may refer to: * Perturbation theory, mathematical methods that give approximate solutions to problems that cannot be solved exactly * Perturbation (geology), changes in the nature of alluvial deposits over time * Perturbat ...

s with the Earth, the Moon and the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. Therefore, it probably entered into

Earth orbit Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi) in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes days (1 sidereal year), during which time Eart ...

very recently, yet there was no recently launched spacecraft that matched the orbit of J002E3. One explanation could have been that it was a 30 meter-wide piece of rock, but

University of Arizona The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory. T ...

astronomers found that spectral observations of the object indicated a strong correlation of absorption features with a combination of human-made materials including white paint, black paint, and aluminum, consistent with

rockets. Back-tracing its orbit showed that the object had been orbiting the Sun for 31 years and had last been in the vicinity of the Earth in 1971. This seemed to suggest that it was a part of the Apollo 14 mission, but NASA knew the whereabouts of all hardware used for that mission; the third stage, for instance, was deliberately crashed into the Moon for seismic studies. The most likely explanation appears to be the

third stage for Apollo 12. NASA had originally planned to direct the S-IVB into a solar orbit, but an extra long burn of the

ullage motor Ullage motors (also known as ullage engines or ullage rockets) are relatively small, independently fueled rocket engines that may be fired prior to main engine ignition, when the vehicle is in a zero-g situation. The resulting acceleration causes ...

s meant that venting the remaining propellant in the tank of the S-IVB did not give the rocket stage enough energy to escape the Earth–Moon system, and instead the stage ended up in a semi-stable orbit around the Earth after passing by the Moon on 18 November 1969. It is thought that J002E3 left Earth orbit in June 2003, and that it may return to orbit the Earth in the mid-2040s.

Potential impact with Earth or Moon

The object's Earth orbital paths occasionally take it within the radius of the

's orbit, and could result in eventual entry into Earth's atmosphere, or collision with the Moon. The Apollo 12 empty S-IVB, Instrument Unit, and spacecraft adapter base, had a mass of about . This is less than one-fifth of the mass of the Skylab space station, which was constructed from a similar S-IVB and fell out of orbit on 11 July 1979. Objects with a mass of about enter Earth's atmosphere approximately 10 times a year, one of which impacts the Earth's surface approximately once every 10 years. Ten essentially similar empty S-IVB stages from Apollo, Skylab and Apollo-Soyuz Test Project missionsThe Apollo missions were:

AS-201 AS-201 (or SA-201), flown February 26, 1966, was the first uncrewed test flight of an entire production Block I Apollo command and service module and the Saturn IB launch vehicle. The spacecraft consisted of the second Block I command module ...

AS-202 AS-202 (also referred to as SA-202) was the second uncrewed, suborbital test flight of a production Block I Apollo command and service module launched with the Saturn IB launch vehicle. It was launched on August 25, 1966, and was the first fl ...

Apollo 4 Apollo 4 (November 9, 1967), also known as SA-501, was the uncrewed first test flight of the Saturn V launch vehicle, the rocket that eventually took astronauts to the Moon. The space vehicle was assembled in the Vehicle Assembly Build ...

Apollo 5 Apollo 5 (launched January 22, 1968), also known as AS-204, was the uncrewed first flight of the Apollo Lunar Module (LM) that would later carry astronauts to the surface of the Moon. The Saturn IB rocket bearing the LM lifted off from C ...

Apollo 6 Apollo 6 (April 4, 1968), also known as AS-502, was the third and final uncrewed flight in the United States' Apollo Program and the second test of the Saturn V launch vehicle. It qualified the Saturn V to be used on crewed missions, as happen ...

, and Apollo 7. The Skylab missions were

Skylab 2 Skylab 2 (also SL-2 and SLM-1) was the first crewed mission to Skylab, the first American orbital space station. The mission was launched on an Apollo command and service module by a Saturn IB rocket on May 25, 1973, and carried NASA astronau ...

Skylab 3 Skylab 3 (also SL-3 and SLM-2) was the second crewed mission to the first American space station, Skylab. The mission began on July 28, 1973, with the launch of NASA astronauts Alan Bean, Owen Garriott, and Jack Lousma in the Apollo command ...

, and

Skylab 4 Skylab 4 (also SL-4 and SLM-3) was the third crewed Skylab mission and placed the third and final crew aboard the first American space station. The mission began on November 16, 1973, with the launch of Gerald P. Carr, Edward Gibson, and Wil ...

. have re-entered the atmosphere from 1966 to 1975. In all cases (including the Skylab station), the objects burned in the atmosphere and broke into relatively small pieces, rather than striking the Earth as a single mass. On the other hand, these objects entered from low Earth orbit or a ballistic trajectory, with less energy than J002E3 might possibly have if it were to enter from solar orbit.

Notes

References

External links

J002E3 Animations
CNEOS

NASA

NASA * , University of Arizona {{DEFAULTSORT:J002e3 Apollo program Apollo 12 Space debris Derelict satellites in heliocentric orbit Near-Earth objects in 2002 Claimed moons of Earth 20020903

Discovery

Potential impact with Earth or Moon

See also

Notes

References

External links