Commander Mark Kelly may get all the glory heading into Friday's launch, but he's essentially a truck driver for the real bonanza aboard space shuttle Endeavour, a scientific experiment to probe the depths of the heavens.
The universe is awash in rapidly moving particles called cosmic rays, the product of everything from the inner workings of stars to as yet unknown explosions at the edge of the universe.wholesale electronics suppliers
The experiment hauled to orbit by Endeavour will give scientists their first extended look at some of these particles, possibly allowing them to unravel some of the cosmos' most closely kept secrets.
"The most exciting objective of this science experiment is to probe the unknown, to search for phenomena that exist in nature that we have not yet imagined nor had the tools to discover," said Samuel Ting, a Nobel Prize-winning physicist who leads the experiment.
Built over the past 17 years, the $2 billion machine, called the Alpha Magnetic Spectrometer (AMS), almost never flew.
As recently as a few years ago NASA administrator Michael Griffin removed the AMS from the shuttle launch schedule because it did not have the funds for an additional flight and was unwilling to risk a space shuttle crew. wholesale Android Tablets
17-year saga
After intense pressure from Congress, which in turn kept hearing from scientists about the significance of the AMS, the mission made it back onto the launch schedule after Charlie Bolden became NASA administrator in 2009.
"It's been quite a saga over the years," said Peter McIntyre, a physicist at Texas A&M University, which is among five dozen institutions that contributed to the project.
"I like to say that professor Ting knows many things, but he's never learned the meaning of the word 'no.' It's thanks to his unswerving persistence that this is going up."
Although space is a vacuum, cosmic rays are constantly zipping around as the by-products of all manner of cosmic phenomenon, from pulsar stars to gamma ray bursts. The 15-foot-wide AMS detector should collect about 25,000 hits per second from cosmic rays.
But scientists really want to see the rare cosmic rays, such as antimatter — electrons with a positive charge - or stranger material still.
Finding them is no small feat.
"In the city of Houston during a thunderstorm you have about 10 billion rain raindrops falling per second," Ting said. "If you want to find one that's of a different color it's somewhat difficult. This illustrates the precision this detector is going to achieve."
'Just the delivery guys'
The AMS has a large magnet and eight different detectors to measure the charge and energy of particles, which will pass through the machine within a few billionths of a second. It is a highly complex device, with more than 300,000 cables and data channels.
Unlike the Hubble Space Telescope, the AMS won't be fixable once launched into space, so scientists have to get it right. And Ting says that's just what he's been doing for the past 17 years. Every electronics system has at least three back-ups.
"My biggest concern every day is to make sure the instrument is correct," he said. "I spend an enormous amount of time thinking about what could go wrong. If it doesn't work you only have one person to blame - me."
The astronauts ferrying the instrument to the space station, where it will be attached and which will provide power to the 15,000-pound AMS, are eager to safely install it on the fourth day of the flight.
"We're just the delivery guys," Endeavour astronaut Mike Fincke said. "We're going to take really good care of this precious commodity."
Like the Hubble Telescope the AMS could open up new vistas to scientists.
Antimatter, dark matter
In space there are two types of cosmic rays. One doesn't carry a charge, like light rays from the sun and distant stars and galaxies. The Hubble instrument afforded scientists a grand view of these rays above Earth's atmosphere for two decades.
At present nearly all of scientists' understanding of the universe comes from the observations of light rays and neutrinos.
But besides light rays and neutrinos there are particles which carry a charge, and therefore have a mass. Earth's 60-mile-thick atmosphere effectively absorbs these charged particles, so scientists haven't been able to effectively observe them from the ground.
Until now. They're hoping to find answers to basic questions like why there's very little antimatter in the universe, when at one point there was probably equal amounts of matter and antimatter, and what exactly dark matter is.
This is a truly important question because, from the rotation of galaxies, scientists know that about 90 percent of the "stuff" in the universe is dark matter, so-called because its nature is wholly unknown.
These are questions that absorb some of the world's most brilliant minds. Among those eagerly awaiting results from the AMS is physicist Stephen Hawking.
"The results may provide the answer to the question, what makes up the universe's missing mass," he said.
No comments:
Post a Comment