Vega 2 (along with
Vega 1
Vega 1 (along with its twin Vega 2) was a Soviet space probe, part of the Vega program. The spacecraft was a development of the earlier '' Venera'' craft. They were designed by Babakin Space Centre and constructed as 5VK by Lavochkin at Khim ...
) was a
Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nation ...
space probe
A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ent ...
part of the
Vega program
The Vega program (Cyrillic: ВеГа) was a series of Venus missions that also took advantage of the appearance of comet 1P/Halley in 1986. ''Vega 1'' and '' Vega 2'' were uncrewed spacecraft launched in a cooperative effort among the Soviet ...
to explore
Halley's comet
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and thus the o ...
and
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
. The spacecraft was a development of the earlier ''
Venera
The Venera (, , which means "Venus" in Russian) program was the name given to a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus. Ten probes successfully landed on the s ...
'' craft. The name VeGa (ВеГа) combines the first two letters Russian words for Venus (Венера: "Venera") and Halley (Галлея: "Galleya") They were designed by
Babakin Space Centre and constructed as
5VK
The 5VK planetary probe (short for 5th-generation Venus-Comet probe) is a designation for a common design used for Soviet unmanned probes to comet 1P/Halley and Venus. It was an incremental improvement of earlier 4MV probes used for Mars and Venu ...
by
Lavochkin
NPO Lavochkin (russian: НПО Лавочкина, OKB-301, also called Lavochkin Research and Production Association or shortly Lavochkin Association, LA) is a Russian aerospace company. It is a major player in the Russian space program, being th ...
at
Khimki
Khimki ( rus, Химки, p=ˈxʲimkʲɪ) is a city in Moscow Oblast, Russia, 18.25 kilometres northwest of central Moscow, and immediately beyond the Moscow city boundary.
History Origins and formation
Khimki was initially a railway station th ...
. The craft was powered by large twin
solar panels. Instruments included an
antenna
Antenna ( antennas or antennae) may refer to:
Science and engineering
* Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves
* Antennae Galaxies, the name of two collid ...
dish,
camera
A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), ...
s,
spectrometer
A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...
,
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
sounder,
magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
s (MISCHA) and
plasma probes. The craft was launched on top of a
Proton 8K82K rocket from
Baikonur Cosmodrome
The Baikonur Cosmodrome ( kk, Байқоңыр ғарыш айлағы, translit=Baiqoñyr ğaryş ailağy, ; russian: Космодром Байконур, translit=Kosmodrom Baykonur, ) is a spaceport in an area of southern Kazakhstan leased to R ...
,
Tyuratam
Töretam ( kk, link=no, Төретам, Töretam; russian: link=no, Тюратам, Tyuratam) is a station on the main Moscow to Tashkent railway, located in Kazakhstan. The name means "Töre's grave" in the Kazakh language. Töre, or more formal ...
,
Kazakh SSR
; kk, Қазақ Советтік Социалистік Республикасы)
*1991: Republic of Kazakhstan (russian: Республика Казахстан; kk, Қазақстан Республикасы)
, linking_name = the ...
. Both Vega 1 and 2 were
three-axis stabilized
Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle/satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, et ...
spacecraft. The spacecraft were equipped with a dual bumper shield for dust protection from Halley's Comet.
Venus mission
The descent module arrived at Venus on 15 June 1985, two days after being released from the Vega 2 flyby probe. The module, a , diameter sphere, contained a surface lander and a
balloon
A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...
explorer. The flyby probe performed a
gravitational assist maneuver using Venus, and continued its mission to intercept the comet.
[NASA—NSSDC—Spacecraft—Details](_blank)
/ref>
Lander
The surface lander was identical to that of Vega 1 as well as the previous six ''Venera
The Venera (, , which means "Venus" in Russian) program was the name given to a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus. Ten probes successfully landed on the s ...
'' missions. The objective of the probe was the study of the atmosphere and the exposed surface of the planet. The scientific payload included a UV spectrometer, temperature and pressure sensors, a water concentration meter, a gas-phase chromatograph, an X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
spectrometer
A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...
, a mass spectrometer
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is us ...
, and a surface sampling device. Several of these scientific tools (the UV spectrometer, the mass spectrograph, and the devices to measure pressure and temperature) were developed in collaboration with French scientists. Since the probe made a nighttime landing, no images were taken.
The Vega 2 lander touched down at 03:00:50 UT on 15 June 1985 at around , in the northern region of Aphrodite Terra
Aphrodite Terra is one of the three continental regions on the planet Venus, the others being Ishtar Terra and Lada Terra. It is named for Aphrodite, the Greek equivalent of the goddess Venus, and is found near the equator of the planet. Aphrod ...
. The altitude of the touchdown site was 0.1 km above the planetary mean radius. The measured pressure at the landing site was 91 atm and the temperature was . The surface sample was found to be an anorthosite
Anorthosite () is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most ...
–troctolite
Troctolite (from Greek τρώκτης 'trout' and λίθος 'stone') is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorth ...
rock, rarely found on Earth, but present in the lunar highlands
The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to " lunar science") is quite different from that of Earth. The Moon lacks a true atmosphere, which eliminates erosion due to weather. It does ...
, leading to the conclusion that the area was probably the oldest explored by any Venera vehicle. It transmitted data from the surface for 56 minutes.
Balloon
The Vega 2 Lander/Balloon capsule entered the Venusian atmosphere (125 km altitude) at 02:06:04 UT (Earth received time; Moscow time 05:06:04) on 15 June 1985 at roughly 11 km/s. At approximately 2:06:19 UT the parachute attached to the landing craft cap opened at an altitude of 64 km. The cap and parachute were released 15 seconds later at 63 km altitude. The balloon package was pulled out of its compartment by parachute 40 seconds later at 61 km altitude, at 7.45 degrees S, 179.8 degrees east. A second parachute opened at an altitude of 55 km, 200 seconds after entry, extracting the furled balloon.
The balloon was inflated 100 seconds later at 54 km and the parachute and inflation system were jettisoned. The ballast was jettisoned when the balloon reached roughly 50 km and the balloon floated back to a stable height between 53 and 54 km some 15 to 25 minutes after entry. The mean stable height was 53.6 km, with a pressure of 535 mbar and a temperature of in the middle, most active layer of the Venus three-tiered cloud system. The balloon drifted westward in the zonal wind flow with an average speed of about 66 m/s at nearly constant latitude. The probe crossed the terminator from night to day at 9:10 UT on 16 June after traversing 7400 km. The probe continued to operate in the daytime until the final transmission was received at 00:38 UT on 17 June from 7.5 S, 76.3 E after a total traverse distance of 11,100 km. It is not known how much further the balloon traveled after the final communication.
Halley mission
After their encounters, the Vegas' motherships were redirected by Venus' gravity to intercept Halley's Comet
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and thus the o ...
.
The spacecraft initiated its encounter on March 7, 1986, by taking 100 photos of the comet from a distance of .
Vega 2 made its closest approach at 07:20 UT on March 9, 1986, at . The data intensive examination of the comet covered only the three hours around closest approach. They were intended to measure the physical parameters of the nucleus, such as dimensions, shape, temperature and surface properties, as well as to study the structure and dynamics of the coma
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...
, the gas composition close to the nucleus, the dust particles' composition and mass distribution as functions of distance to the nucleus and the cometary-solar wind
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
interaction.
During the encounter, Vega 2 took 700 images of the comet, with better resolution than those from the twin Vega 1
Vega 1 (along with its twin Vega 2) was a Soviet space probe, part of the Vega program. The spacecraft was a development of the earlier '' Venera'' craft. They were designed by Babakin Space Centre and constructed as 5VK by Lavochkin at Khim ...
, partly due to the presence of less dust outside the coma at the time. Yet Vega 2 recorded an 80% power loss during the encounter as compared to Vega 1's 40%.
After further imaging sessions on 10 and 11 March 1986, Vega 2 finished its primary mission.
Post Halley
A 6 million kilometer distant flyby of 2101 Adonis was considered but it turned out that Vega 2 didn't have enough fuel left to make the necessary orbital changes for the flyby. Instead the Vega probes took the opportunity to measure the dust as they passed through the orbits of 72P/Denning–Fujikawa, Biela's Comet
Biela's Comet or Comet Biela (official designation: 3D/Biela) was a periodic Jupiter-family comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela. It was subsequently observed to ...
and 289P/Blanpain.
Contact with Vega 2 was lost on 24 March 1987. Vega 1 had previously exhausted its attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
propellant on 30 January 1987.
Vega 2 is currently in heliocentric orbit
A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun i ...
, with perihelion
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ellip ...
of 0.70 AU, aphelion
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ell ...
of 0.98 AU, eccentricity
Eccentricity or eccentric may refer to:
* Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal"
Mathematics, science and technology Mathematics
* Off-Centre (geometry), center, in geometry
* Eccentricity (g ...
of 0.17, inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...
of 2.3 degrees and orbital period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...
of 281 days.
See also
*List of missions to Venus
There have been 46 (including gravity-assist flybys) space missions to the planet Venus. Missions to Venus constitute part of the exploration of Venus.
List
As of 2020, the Soviet Union, United States, European Space Agency and Japan have con ...
References
External links
Vega 2 Measuring Mission Profile
b
NASA's Solar System Exploration
Raw data from Vega 1 and Vega 2 on board instruments
''Vega 2'' Mission Comet Halley Data Archive
at the NASA Planetary Data System, Small Bodies Node
{{Orbital launches in 1984
Missions to Halley's Comet
Vega program
Derelict satellites in heliocentric orbit
1984 in spaceflight
1984 in the Soviet Union
Derelict space probes
France–Soviet Union relations
Extraterrestrial aircraft
Spacecraft launched in 1984
Extraterrestrial atmosphere entry