Phobos program

Phobos program

Infobox_Spacecraft
Name = Phobos 2


Caption = Illustration of the Phobos spacecraft
Organization = IKI
Major_Contractors =
Mission_Type = Orbiter
Satellite_Of = Mars
Orbital_Insertion_Date = January 29, 1989
Launch = July 12, 1988
Launch_Vehicle = Proton-K rocket
Decay =
Mission_Duration =
NSSDC_ID = 1988-059A
Webpage = [http://www.iki.rssi.ru/IPL/phobos.html]
Mass = 2600 kg (6220 kg with orbital insertion hardware attached)
Power =
Orbital_elements =
Semimajor_Axis =
Eccentricity =
Inclination =
Orbital_Period =
Apoapsis =
Periapsis =
Orbits =

The Phobos ( _ru. Фобос, Fobos) program was an unmanned space mission consisting of two probes launched by the Soviet Union to study Mars and its moons Phobos and Deimos. Phobos 2 became a Mars orbiter and returned 38 images with a resolution of up to 40 meters. Both probes suffered from critical failures.

Phobos 1 and 2 were of a new spacecraft design, succeeding the type used in the Venera planetary missions of 1975-1985, last used during the Vega 1 and Vega 2 missions to comet Halley.

Phobos 1 was launched on July 7, 1988 and Phobos 2 on July 12, 1988, each aboard a Proton-K rocket. They each had a mass of 2600 kg (6220 kg with orbital insertion hardware attached).

The program featured co-operation from 14 other nations including Sweden, Switzerland, Austria, France, West Germany, and the United States (who contributed the use of its Deep Space Network for tracking the twin spacecraft).

Objectives

The objectives of the Phobos missions were to:

* conduct studies of the interplanetary environment;
* perform observations of the Sun;
* characterize the plasma environment in the Martian vicinity;
* conduct surface and atmospheric studies of Mars; and,
* study the surface composition of the Martian satellite Phobos.

pacecraft design

The main section of the spacecraft consisted of a pressurized toroidal electronics section, surrounding a modular cylindrical experiment section. Below these were mounted four spherical tanks (the Fregat vehicle) containing hydrazine for attitude control and, after the main propulsion module was to be jettisoned, orbit adjustment. A total of 28 thrusters (twenty-four 50 N thrusters and four 10 N thrusters) were mounted on the spherical tanks, with additional thrusters mounted on the spacecraft body and solar panels. Attitude was maintained through the use of a three-axis control system, with pointing maintained with Sun and star sensors.

Phobos 1

Phobos 1 operated nominally until an expected communications session on 2 September 1988 failed to occur. The failure of controllers to regain contact with the spacecraft was traced to an error in the software uploaded on 29 August/30 August, which had deactivated the attitude thrusters. By losing its lock on the Sun, the spacecraft could no longer properly orient its solar arrays, thus depleting its batteries.

A natural question is "Why would a spacecraft have instructions that turn off the attitude control, normally a fatal operation?" In this case, these instructions were part of a routine used when testing the spacecraft on the ground. Normally this routine would be removed before launch. However, the software was coded in PROMs, and so removing the test code required removing and replacing the entire computer. Because of time pressure from the impending launch, engineers decided to leave the command sequence in, though it never should be used. However, a single character error in constructing an upload sequence resulted in the command executing, with subsequent loss of the spacecraft. [ [http://catless.ncl.ac.uk/Risks/9.24.html#subj3 "Risks digest" summary of the accident] ]

Phobos 2

Phobos 2 operated nominally throughout its cruise and Mars orbital insertion phases on January 29, 1989, gathering data on the Sun, interplanetary medium, Mars, and Phobos. Shortly before the final phase of the mission, during which the spacecraft was to approach within 50 m of Phobos' surface and release two landers, one a mobile "hopper", the other a stationary platform, contact with Phobos 2 was lost. The mission ended when the spacecraft signal failed to be successfully reacquired on March 27, 1989. The cause of the failure was determined to be a malfunction of the on-board computer.

The Phobos design was used again for the long delayed Mars 96 mission which ended in failure when the launch vehicle's fourth stage misfired.

ystems and sensors

Phobos probes carried several instruments: solar x-ray and ultraviolet telescopes, a neutron spectrometer and the Grunt radar experiment designed to study the surface relief of Phobos. The lander had an x-ray/alpha spectrometer to provide information on the chemical element composition of the surface of Phobos, a seismometer to determine the internal structure of Phobos, and the "Razrez" penetrator with temperature sensors and an accelerometer for testing the physical and mechanical properties of the surface.

The Phobos 2 infrared spectrometer (ISM) obtained 30 000 spectra in the near infrared (from 0.75 to 3.2 µm) in the equatorial areas of Mars, with a spatial resolution ranging from 7 to 25 km, and 400 spectra of Phobos at 700 m resolution. These observations made it possible to retrieve the first mineralogical maps of the planet and its satellite, and to study the atmosphere of Mars. ISM was developed at IAS and DESPA (Paris Observatory) with support from CNES.

List of instruments:
* "VSK" TV imaging system
* PROP-F "hopping" lander. Only carried by Phobos 2.
**ARS-FP automatic X-ray fluorescence spectrometer
**ferroprobe magnetometer
**Kappameter magnetic permeability / susceptibility sensor
**gravimeter
**temperature sensors
**BISIN conductometer / tiltmeter
**mechanical sensors (penetrometer, UIU accelerometer, sensors on hopping mechanism)
*"DAS" (long-lived autonomous station) lander
**TV camera
**ALPHA-X Alpha-Proton-X-Ray Spectrometer
**LIBRATION sun sensor (also known as STENOPEE)
**Seismometer
**RAZREZ anchor penetrometer
**Celestial mechanics experiment
* "ISM" thermal infrared spectrometer/radiometer - 1-2 km resolution
* near-infrared imaging spectrometer
* thermal imaging camera; magnetometers
* gamma-ray spectrometers
* X-ray telescope
* radiation detectors
* radar and laser altimeters
* Lima-D laser experiment - designed to vaporise material from the Phobos surface for chemical analysis by a mass spectrometer
* "Grunt" imaging radar - Only carried by Phobos 1

ee also

*Exploration of Mars
*Space exploration

References

*cite journal
author = R. Z. Sagdeev & A. V. Zakharov
title = Brief history of the Phobos mission
journal = Nature
year = 1989
volume = 341
issue =
pages = 581–585
doi = 10.1038/341581a0

* Articles in Nature 341 (1989) pages 581 - 619
*http://nssdc.gsfc.nasa.gov/planetary/phobos.html
*http://www.astronautix.com/craft/fobos1f.htm
*http://www.ias.u-psud.fr/ism/DRV_DATA/HTML/ISM/WELCOME.HTM

External links

* [http://www.strykfoto.org/phobos2.htm High quality processed images from the Phobos 2 mission]
* [http://www.iki.rssi.ru/IPL/phobos.html Phobos mission images from the Space Research Institute (IKI)]
* [http://www.ias.u-psud.fr/ism/ Raw image data from the Phobos 2 ISM infrared instrument]
* [http://www.federalspace.ru/Doc1Show.asp?DocID=16 What we are searching for on Phobos] - an article on the Phobos program at the Web site of the Russian Space Agency
* [http://astrosurf.com/nunes/explor/explor_ph2.htm Another site with processed images from the Soviet Phobos 2 mission]
* [http://www.planetary.org/data/phobos2/index.html The Complete Phobos 2 VSK Image Data Set]


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Phobos (moon) — Phobos Enhanced color view of Phobos obtained by Mars Reconnaissance Orbiter on March 23, 2008. Stickney crater, the largest, is on the right side. Discovery Discovered by …   Wikipedia

  • Phobos — Phobos, Greek for fear , is the root word of phobia . It may refer to:*Phobos (mythology), one of the sons of Ares and Aphrodite in Greek mythology *Phobos (moon), the larger and innermost of Mars two moons *Phobos (physics) is a nuclear physics… …   Wikipedia

  • Phobos-Grunt — Infobox Spacecraft Name = Phobos Grunt Caption = Organization = Russian Federal Space Agency Major Contractors = Mission Type = Orbiter, lander, sample return Flyby Of = Phobos Satellite Of = Mars Orbital Insertion Date = Launch = October 2009… …   Wikipedia

  • Mars program — This article is about the Soviet program. For other Mars exploration programs, see Exploration of Mars. The Mars program was a series of unmanned spacecraft launched by the Soviet Union between 1960 and 1973. The spacecraft were intended to… …   Wikipedia

  • Mars probe program — This article is for the Russian (Soviet) series of space probes; for the moon designated as Mars II, see Deimos (moon); for all missions to Mars, see Exploration of Mars. The Mars program was a series of Mars unmanned landers and orbiters… …   Wikipedia

  • Planetary Observer program — The Planetary Observer program is a cancelled space exploration program designed by NASA to provide cheaper planetary orbiters by utilising Earth orbiting satellite components and technology, using solar panels for power, and a common spacecraft… …   Wikipedia

  • Chinese space program — This article is about the Chinese space program in general. For the current Chinese space agency since 1993, see China National Space Administration. The launch of Tianlian, Xichang Center The space program of the People s Republic of China is… …   Wikipedia

  • Professor Phobos — Superherobox| caption= comic color=background:#ff8080 character name=Professor Phobos real name=Piotr Phobos species=Human Mutant publisher=Marvel Comics debut= Incredible Hulk #258 (Apr 1981) creators=Bill Mantlo and Sal Buscema alliance… …   Wikipedia

  • Mars Scout Program — The Mars Scout Program was a NASA initiative to send a series of small, low cost robotic missions to Mars, competitively selected from innovative proposals by the scientific community. The program would have had an array of missions destined to… …   Wikipedia

  • Chinese Mars exploration program — Little is known of the Chinese Mars exploration program. While the Moon is the first priority, there are plans for Martian exploration that follow upon the work done in the Chinese Lunar Exploration Program. China has been studying the necessity… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”