17 January 2008

"To Jupiter"- informal translation on article by Karen Rubin, Panorama, February 7, 2008

(informal translation prepared by U.S. Embassy – Rome, Italy)

NASA is preparing one of the most ambitious of missions: to send a probe to the largest planet in our solar system. To narrate the details to Panorama is one of the project scientists.

It will be called Juno and will travel five years to reach Jupiter. The new NASA satellite will be launched from Cape Canaveral in October 2011, for the next expedition to this gigantic planet, the most massive in the solar system. It will also be (significant news) an ecological satellite. “It will have three, six-meter-long solar panels that will supply all of the energy necessary for remaining in proximity to Jupiter,” explains Scott Bolton, head [Principal Investigator] of the group working on the project, to Panorama while in Rome the past few days to present the mission. “The purpose is to study the atmosphere of Jupiter and understand something more of its nature. To discover how it may be formed means to have useful information for the Earth as well.”

Interest on the part of the American space agency in Jupiter is not new. In 1973 the Pioneer 10 and 11 probes flew over it, photographing it for the first time. Then they launched Voyager 1 and 2, Cassini and Galileo (the last one arrived on the planet in 1995). “This mission is, however, profoundly different from the others. Juno will not only execute a flyby, which is a passage up close and then departing, but it will enter in Jupiter’s orbit and gravitate around the poles for a year,” continues Bolton. The other probes had flown over the planet, but only in proximity of the equator.

“To observe the poles means to obtain data from the inside of the planet,” states Enrico Flamini, the head of the solar system exploration program of the Italian Space Agency. There will be an instrument made in Italy, called the radio science experiment, to measure the infinitesimal shifts in the motion of Juno and to establish the characteristics of the gravitational field of Jupiter.

The planet is composed of 90 percent hydrogen (which in the earth’s atmosphere is a very low percentage, 0.00005 percent). According to scientists’ hypotheses, below the atmosphere the hydrogen would change from gas to liquid, and going toward the planet’s nucleus it would be compressed further, and transformed into metal.

It is exactly this high concentration of metallic hydrogen that determines the enormous magnetic field of Jupiter. “For this reason we hold that life down there may be impossible, at least life how we humans understand it,” says Bolton. Also because the gravity on Jupiter is high: a man that weighs eighty kilograms on earth would weigh two thousand there. He would have to support on his head not the 1,000 millibar of earthly atmosphere, but the weight of some billion millibar, inconceivable,” adds Flamini.

Italy also contributes to the NASA mission with the infrared spectrometer JIRAM, capable of studying Jupiter’s atmosphere, distinguishing the elements that comprise it and calculating the percentages. “We will also study the dynamics of Jupiter’s atmosphere. To understand it will permit us to better comprehend the evolution of this terrestrial body,” explains Angioletta Coradini, Director of the Institute of Physics and Interplanetary Space at the University of Tor Vergata, whose group conceived the instrument.

The existing theories on the formation of the planet still await verification. “We think that Jupiter was the first planet to be formed. Since it is the largest, if it had been formed later its gravitational attraction would have destroyed all of the others. Our ambition is to discover what was the first step toward life. Our dream is to know all the succeeding steps, also to be able to imagine the future of our planet,” concludes Bolton.

What We Know of this Giant

• The Lord of the Solar System. Jupiter is the biggest planet; its mass is two and a half times that of all the other planets’ masses combined.

• A Court of Satellites. Various moons orbit around Jupiter. The most important are: Io, Europa, Ganymede, and Callisto.

• Juno Will Be Seen from Close Up. The probe Juno, departure date 2011, will be fed by three solar panels. Onboard it will also have an Italian infrared spectrometer : JIRAM