Cape Canaveral, Florida, Aug 6: American space agency NASA on Friday morning launched its $ 1.1 billion space probe named Juno to Jupiter, the largest planet of the solar system.
An Atlas 5 rocket was launched from Cape Canaveral Air Force Station after a brief delay caused by a helium leak.
The unmanned Nasa space probe will cruise beyond Mars to put itself in orbit around the gas giant in 2016.
It is the first solar-powered mission to venture this far from the Sun.
The mission launched atop an Atlas 5 rocket from the Cape Canaveral Air Force Station on Friday at 12:25 local time (16:25 GMT, 21:55 IST) after a brief delay caused by a helium leak.
There were concerns with the helium charging system on the rocket's Centaur upper stage, but a small leak on the “ground side” of the rocket was found to be the culprit.
“Today, with the launch of the Juno spacecraft, Nasa began a journey to yet another new frontier,” said the agency's administrator Charles Bolden.
“The future of exploration includes cutting-edge science like this to help us better understand our Solar System and an ever-increasing array of challenging destinations.”
At Jupiter, where the intensity of sunlight is only 1/25th of that at Earth, space missions would normally resort to a plutonium battery.
But Juno will instead travel with three wings coated with 18,000 solar cells.
“As a solar-panelled mission, we have to keep those solar panels facing the Sun and we never go into Jupiter's shadow,” the mission's chief scientist Scott Bolton said.
It is one of the space agency's most ambitious missions and will attempt to discover the secrets behind the largest planet in the solar system.
Juno, which will arrive at Jupiter in 2016, will study the planet's core, atmosphere, powerful magnetic field and auroras.
Once it reaches its target it will be the furthest-travelled solar-powered probe and the fastest man-made object in history after travelling at 160,000mph.
Nasa said the aim of the pioneering voyage was to learn more about how the solar system was created and unlock many of it secrets that have remained a mystery until now.
Senior space agency officials have spent the past 10 years planning the mission, which is part of its New Frontiers planetary expeditions and is managed by the Jet Propulsion Laboratory in La Canada Flintridge, California.
The unmanned satellite observatory is named after the ancient Roman goddess who spied through clouds on her husband Jupiter and is the first Nasa probe to orbit Jupiter since the Galileo mission ended in 2003.
With the end of the space-shuttle program, Nasa has faced criticism that its approach to manned space exploration is aimless but this year the space agency has turned its attention to unmanned exploration, particularly to deep space.
“Jupiter holds secrets about how the solar system formed,” said Nasa's Dr Scott Bolton, the mission's chief scientist.
“We want to get the list of ingredients that produced the recipe for planets. That will give us guidance of what happened in that early time that eventually led to us.
“If we want to go back in time and understand where we came from and how the planets were made, Jupiter holds this secret.”
He added: “Jupiter was likely the first planet to form, and by learning more about the earliest steps in the history of the solar system, we learn about our history too.
“By going back to square one with Jupiter, we get to understand how we got here.”
The spacecraft was launched aboard the Atlas V551, the most powerful rocket in Nasa's inventory following the retirement of the space shuttle.
The 3.5 tonne spacecraft unfurled three 29-foot long solar panels to provide power to Jupiter, five times farther from the sun than Earth is.
The robotic probe is scheduled to spend one year cycling inside Jupiter's deadly radiation belts, far closer than any previous orbiting spacecraft.
Its nine instruments, which are fed information from 29 sensors, have been built to be able to penetrate its dense 25,000-mile thick gas clouds to learn more about what the planet is made of.
It will gather evidence on how much water the giant planet holds, what triggers its vast magnetic fields and whether a solid core lies beneath its dense, hot atmosphere.
It will also try to measure the depth of Jupiter's “Red Spot,” a massive hurricane-like storm more than 15,000 miles wide.
Juno's sensitive electronics will be shielded inside a titanium vault with walls nearly half an inch thick to protect them from overheating.
But the mission is only expected to last a year due to such high levels of radiation and a magnetic field that is 14 times stronger than Earth's.
“We're basically an armored tank going to Jupiter,” said Dr Bolton, an astrophysicist. “We're getting closer to Jupiter than any other spacecraft has gone.”
The probe will be 20 yards wide with its giant solar panels fully extended. They will soak up energy 500 million miles from the sun. Also on board the spacecraft will be three Lego figurines.
One of the 1.5 inch high Lego models is of Galileo, the Italian astronomer who used one of the first telescopes to discover the four main moons of Jupiter.
The others are of the Roman gods after whom Jupiter and Juno, his mythical wife, were named.
Jupiter is the largest of the solar system's planets, containing more than twice the amount of matter as all of the other planets combined.
It is the size of 1,300 Earths combined and contains most of the material left in the solar system after the solar system formed about 4.6 billion years ago. It has at least 63 moons, one bigger than Mercury.
Temperatures on Jupiter drop to -234 degrees F, thick brooding clouds obscure its atmosphere and winds blow at up to 384 miles per hour.
“The special thing about Juno is we're really looking at one of the first steps, the earliest time in our solar system's history,” said Dr Bolton, who is based at the Southwest Research Institute's Space Science Division in San Antonio.
“Right after the sun formed, what happened that allowed the planets to form and why are the planets a slightly different composition than the sun?
“These are the elements of life, the elements that Earth is made out of. How Jupiter managed to get enriched in these elements is right at the essence of how we got here.”
Nasa said the Lego figurines are flying on the probe to inspire schoolchildren about science. Scientists from the University of Leicester have also been involved with mission's planning.