IKAROS
Encyclopedia
IKAROS is a Japan Aerospace Exploration Agency
Japan Aerospace Exploration Agency
The , or JAXA, is Japan's national aerospace agency. Through the merger of three previously independent organizations, JAXA was formed on October 1, 2003, as an Independent Administrative Institution administered by the Ministry of Education, Culture, Sports, Science and Technology and the...

 (JAXA) experimental spacecraft. The spacecraft was launched on 21 May, 2010, aboard an H-IIA
H-IIA
H-IIA is an active expendable launch system operated by Mitsubishi Heavy Industries for the Japan Aerospace Exploration Agency . The liquid-fueled H-IIA rockets have been used to launch satellites into geostationary orbit, to launch a lunar orbiting spacecraft, and to launch an interplanetary...

 rocket, together with the Akatsuki (Venus Climate Orbiter) probe and four other small spacecraft. IKAROS is the first spacecraft to successfully demonstrate solar-sail technology in interplanetary space.

On December 8, 2010, IKAROS passed by Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

 at about 80,800 km distance, completing the planned mission successfully, and entered its extended operation phase.

Purpose

The IKAROS probe is the world's first spacecraft to use solar sail
Solar sail
Solar sails are a form of spacecraft propulsion using the radiation pressure of light from a star or laser to push enormous ultra-thin mirrors to high speeds....

ing as the main propulsion. It plans to demonstrate four key technologies (comments in parentheses refer to figure):
  1. Deployment and control of a large, thin solar sail membrane (blue areas numbered 3)
  2. Thin-film solar cells integrated into the sail to power the payload (black rectangles numbered 4)
  3. Measurement of acceleration due to radiation pressure on the solar sail
  4. Attitude control via variable reflectance liquid crystal panels (orange rectangles numbered 2)


The mission also includes investigations of aspects of interplanetary space, such as the gamma-ray burst, solar wind
Solar wind
The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...

 and cosmic dust
Cosmic dust
Cosmic dust is a type of dust composed of particles in space which are a few molecules to 0.1 µm in size. Cosmic dust can be further distinguished by its astronomical location; for example: intergalactic dust, interstellar dust, interplanetary dust and circumplanetary dust .In our own Solar...

.

The probe's ALADDIN instrument (ALDN-S and ALDN-E) measured the variation in dust density while its Gamma-Ray Burst Polarimeter (GAP) measured the polarization of gamma-ray bursts during its six month cruise.

If successful, IKAROS is to be followed by a 50 m (164 ft) sail, intended to journey to Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

 and the Trojan asteroids, later in the decade.

Design

The square sail, deployed via a spinning motion using 0.5 kg tip masses (1 in key at right), is 20 m (65.6 ft) on the diagonal and is made of a adj=on 7.5 thick sheet of polyimide
Polyimide
Polyimide is a polymer of imide monomers. The structure of imide is as shown. Polyimides have been in mass production since 1955...

 (3 in key at right). A thin-film solar array is embedded in the sail (4 in key at right). PowerFilm, Inc.
PowerFilm, Inc.
PowerFilm, Inc. is a publicly held energy company in the solar sector. It manufactures photovoltaic solar modules using a thin film semiconductor process. PowerFilm was founded in 1988 by Dr. Frank Jeffrey and Dr. Derrick Grimmer, former 3M research physicists with a combined 65 years of...

 provided the thin-film solar array. Eighty blocks of LCD
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....

 panels are embedded in the sail, whose reflectance can be adjusted for attitude control (2 in key at right). The sail also contains eight dust counters on the opposite face as part of the science payload.

Mission progress

IKAROS was successfully launched together with Akatsuki (the Venus Climate Orbiter) aboard an H-IIA rocket from the Tanegashima Space Center
Tanegashima Space Center
The is one of Japan's space development facilities. It is located on Tanegashima, an island located 115 km south of Kyūshū. It was established in 1969 when the National Space Development Agency of Japan was formed...

 on 21 May 2010.

IKAROS spun at 20–25 revolutions per minute and finished unfurling its sail on 11 June 2010. The craft contains two tiny ejectable cameras, DCAM1 and DCAM2. DCAM2 was used to visualise the sail after deployment on 14 July 2010.

The sail finished deploying on 10 June 2010.

Acceleration and attitude control were successfully tested during the remaining six month voyage to Venus. On 9 July 2010, JAXA confirmed that IKAROS is being accelerated by its solar sail, and on 23 July announced successful attitude control.

IKAROS continues to spin at approximately 2 rpm
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...

, requiring the LCD panels to be cycled at that rate for attitude control.

See also

  • NanoSail-D2
    NanoSail-D2
    NanoSail-D2 is a small satellite built by NASA's Marshall Space Flight Center and Ames Research Center to study the deployment of a solar sail in space. It is a three-unit CubeSat measuring 30 by 10 by 10 centimeters , with a mass of...

    , an American solar sail deployed in LEO in January 2011
  • LightSail-1
    LightSail-1
    LightSail-1 is a solar sail project being developed by the Planetary Society, a non-profit organization devoted to space exploration. LightSail-1 was announced in November 2009. The kite-shaped spacecraft will have a total cross-section of , and will be fitted with guidance and diagnostic electronics...

    , a private solar sail project of the Planetary Society
    Planetary Society
    The Planetary Society is a large, publicly supported, non-government and non-profit organization that has many research projects related to astronomy...

  • Icarus
    Icarus
    -Space and astronomy:* Icarus , on the Moon* Icarus , a planetary science journal* 1566 Icarus, an asteroid* IKAROS, a interplanetary unmanned spacecraft...


External links

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