The Akatsuki probe puts its name to the first Japanese mission to the Earth’s sister.
Lift-off of the H-IIA launch vehicle on 20 May (21 May at 06:58 in Japan). The Japanese rocket successfully placed the Akatsuki probe and the Ikaros solar sail in orbit. Credit: JAXA
If there are two planets in the solar system that resemble one another, it is the Earth and Venus. Both are telluric (essentially made of rocks and endowed with a solid surface, Mercury and Mars are also telluric planets), and are of comparable diameters: 12,102 km for Venus and 12,756 km for the Earth. However, the climate on that which is also known as the Morning or Evening Star is like hell with a surface temperature of 460°C!
A climate machine out of control Thanks to several robotic missions, space exploration has made it possible to draw up an accurate picture of this planet that is subject to an overheating of its climactic machine due to its CO2-saturated atmosphere which explains a greenhouse effect with extreme consequences. In 2006, the European probe Venus Express went into orbit around the Earth’s sister and led a renewal of Venusian exploration as the previous mission dated back to 1989 with the American probe Magellan launched by the space shuttle Atlantis. The Magellan mission having ended in 1994, it had been 12 years since Venus had been surveyed by any space probes! With the successful launch of Akatsuki (“Dawn” in Japanese) on 20 May, it is now, for the very first time, Japan’s turn to take a close look at the second planet in the solar system. The video from JAXA, the Japanese Space Agency, below explains the objectives of this mission.
Scientists from the Land of the Rising Sun are obviously interested in its climate as the other name for the probe, Venus Climate Orbiter, proves. This 640 kg spacecraft is to arrive at its destination in December 2010 and is equipped with 5 cameras that work in the infrared and ultraviolet light wave ranges. This is going to literally make it possible to study the Venusian atmosphere in “sections” as each wavelength enables different altitudes and phenomena to be explored. It is also worthy of note that one of the cameras is to find out whether a lightning phenomenon comparable to that which regularly takes place on Earth also occurs on Venus. Another uncertainty that Akatsuki intends to study: volcanism that could still be active; a subject recently revived by data from Venus Express (see this article). An infrared camera belonging to the Japanese robotic explorer has been designed with this in mind. And lastly, a sixth instrument using radio waves is to measure the temperatures that prevail at different altitudes in the Venusian atmosphere. The waves emitted by the probe will actually be received on Earth once they have passed through the atmosphere on Venus: the alteration of the signal will indicate the temperatures encountered.
Akatsuki (illustration): with this probe, Japan will be studying Venus for the first time from its orbit. It is scheduled to arrive later this year in December. Credit: JAXA
A solar sail invited to the launch The H-IIA launcher that blasted off from the Tanegashima Space Centre on 20 May 2010 was not just carrying the Akatsuki probe. A solar sail was a sort of “guest” in order to test this principle of propulsion where photons emitted by the Sun hit a wide surface area (the sails), which provides thrust in return. This experimental spacecraft, dubbed Ikaros (an allusion to Icarus but also an acronym for Interplanetary Kite-craft Accelerated by Radiation Of the Sun) consists of a square sail 20 m in diagonal which will open out within the next few weeks just by means of centrifugal force as the device rotates. JAXA’s objective is ambitious: the Ikaros controllers are hoping to reach Venus in a 6 month time period.
The solar sail Ikaros (illustration). This experimental spacecraft is going to enable the Japanese Space Agency to test this innovative principle of propulsion. Credit: JAXA
A second solar sail is even scheduled towards the end of the 2010 decade. This time with a 50 m diameter, the aim would be to explore Jupiter. But then what is more logical for the Land of the Rising Sun than to study the possibilities of such “solar yachts”?
This is the mythical rocket par excellence, the one that launched Sputnik, the first satellite and Gagarin, the first man in space. The CSG, Guiana Space Centre, is now one of its launch bases: a historic achievement.
The first episode of this famous science-fiction series was broadcast in September 1966. NASA has often made references to these programmes, as in the case of the space shuttle Enterprise, which had the same name as the spaceship in the series.
50 years ago on 5 May 1961, a few weeks after Gagarin, American Alan Shepard reached space. Several years later, he was to walk on the Moon, summarising as it were the race in which the Soviet Union and the United States were competing.
