from Bill Still
lass=”” >About the time 4th of July fireworks are coming to an end on the East Coast of the US, the giant Juno spacecraft will wake up after a 5-year journey to Jupiter and begin a 35-minute engine burn that slow down the fastest object ever launched from earth so it can be captured around this solar system’s largest planet, Jupiter.
Scientists hope that at 23:06, Juno will phone home that the engine burn is complete and the proper speed has been achieved.
That message will take 48 minutes to travel the 5.7 million miles to reach NASA’s Jet Propulsion Laboratory in Pasadena, California.
Juno will then orbit Jupiter for about 20 months, circling in 37 highly-elliptical orbits bringing the spacecraft as close as within 3100 miles and as distant as 2,000,000 miles from the planet’s surface. Each orbit will bring it closer and closer until on orbit #37, Juno will burn up in the dense atmosphere.
Juno was launched nearly 5 years ago. The 4-ton spacecraft was launched in an awkward-looking configuration atop an Atlas V rocket with 5 extra solid rocket boosters strapped to the outsides to give it sufficient thrust for the 5-year voyage to Jupiter.
What are scientists interested in discovering on Jupiter? How far down does the Giant Red Spot extend?
O What causes it to be there, swirling with wind speeds of between 430 and 680 miles per hour – 3 to 4 times greater than the strongest earthbound tornadoes.
Another unusual feature of Jupiter – which is 3 times larger than the next-largest planet, Saturn – is the powerful magnetic field – so powerful that it creates gigantic glowing auroras around its poles.
Could it be that the giant planet – nearly large enough to have developed into another sun – creates pressures so great deep inside its interior that the liquid hydrogen which comprises 75% of its mass, is compressed so tightly that it becomes metallic – something that has never been observed on earth, but is known as “the holy grail of high-pressure physics.”
Metallic hydrogen would probably be a superconductor and could be responsible for the immense magnetic and radiation field that surrounds the planet. Other theories hypothesize that at these pressures, entirely new states of matter called superconducting superfluids and metallic superfluids may exist.
No matter the cause, the Juno spacecraft will carefully try to avoid the most powerful areas in Jupiter’s radiation field lest its instrument be fried before it can begin transmitting scientific data in October.
To try to preserve those instruments for as long as possible, many are secured inside a radiation vault made of 2-inch-thick titanium walls and about 36 inches on a side.
Juno is expected to experience radiation levels equivalent to 100 million dental x-rays.
The possibilities for scientific breakthroughs abounds in this, the most dangerous – and next-to-last of NASA’s interplanetary missions.
The last NASA interplanetary mission will come to an end next year when the Cassini spacecraft, first launched in 1997, will return to Saturn and eventually crash into it in what scientists call the Grand Finale.
I’m Still reporting from Washington. Good day.