05.16.11

Persistence and the Power of Discovery

AMS experiment launched aboard the Space Shuttle Endeavour.

Click to enlarge photo. Enlarge Photo

AMS experiment NASA/courtesy of nasaimages.org

AMS experiment being prepared for the Endeavour’s payload bay.

Every science experiment is an endeavor, a curiosity-inspired attempt to discover, to uncover a truth about the world or the universe. Each endeavor is also a risk and an opportunity to find something truly unexpected.

For that reason, persistence can be an undervalued quality in (eventually) successful science experiments. And persistence is at the heart of the DOE Office of Science-supported Alpha Magnetic Spectrometer (AMS) experiment, which launched on May 16th aboard the final mission of the Space Shuttle Endeavour.

When installed on the outside of the International Space Station (ISS), the AMS experiment, led by Dr. Samuel Ting, a Nobel laureate from MIT supported by the Office of Science, will sweep the sky for cosmic rays. Despite their exotic name, cosmic rays are basically broken up bits of atoms — protons, electrons, and atomic nuclei — which fly across the universe at near-light speed, driven by natural accelerators such as the enormous explosions known as supernovas. Since the earth's atmosphere absorbs and blocks most cosmic rays, it's necessary to position a detector in outer space to capture the rarest of them.

Click to enlarge photo. Enlarge Photo

Space Shuttle Endeavor NASA/courtesy of nasaimages.org

Endeavour rolls out of the Vehicle Assembly Building.

In addition to measuring how cosmic rays flow and what they are made of, the AMS will also search for cosmic rays made of a special form of matter known as antimatter. Antimatter is like matter, but with generally the opposite charge. For instance, a proton has a positive charge, and its antimatter opposite is the antiproton, which has a negative charge. When they collide, enormous energy is released as the particles annihilate one another.

In the instants after the origin of the universe in the Big Bang, it is believed that the universe contained matter and antimatter in equal proportion. Today's universe, however, is composed of matter and whether antimatter survives at all in the universe (it has been and continues to be created in laboratories) is one of the big questions AMS is trying to answer.

Dr. Ting and other scientists believe that some of the particles detected by the AMS could come from an even more exotic source called dark matter. Dark matter is believed to make up nearly a quarter of the universe. (Dark energy accounts for an even bigger portion, but that's a subject for a different endeavor.) So by looking for new particles in space via the AMS, scientists might tell us more about the composition of the Universe.

How do you capture a tiny particle moving at incredible speed? To borrow an image from baseball, you use a big mitt. And you get a big team. Specifically, the heart of the AMS experiment is a large magnet connected to multiple sensors. That forms the 'mitt.'

Meanwhile, the team came together from all across the globe. More than 600 scientists and engineers from some 16 countries — European and Asian — have worked on the AMS experiment. Its construction was actually centered at CERN, the European Organization for Nuclear Research, and many European states provided the preponderance of AMS financial support.

Assembling the team, and the equipment, took time. In fact, the AMS has been more than a decade in the making. NASA first agreed to loft the experiment more than 15 years ago (1994), and a prototype was flown in 1998. But the loss of the shuttle Columbia delayed the flight, and then other factors moved the experiment entirely off the manifest.

Click to enlarge photo. Enlarge Photo

Space Shuttle Endeavor on the launch pad NASA/courtesy of nasaimages.org

Endeavour ready for launch.

However, Dr. Ting persisted. In 2009, AMS was again put on the flight schedule. That wasn't the end of the story though. Last year, extensive testing of the experiment's superconducting magnet (the heart of its "mitt") showed that it might not last the length of its mission. So Dr. Ting and his team stripped out the superconducting magnet and replaced it with a less-powerful, but proven permanent magnet, one that, combined with other alterations of the detector's configuration, will still be able to accomplish the mission's goals by sweeping the sky for longer periods of time.

Data collection could start as soon as a few hours after AMS is installed, though analyzing the information will take time. Much of the analysis will be performed by scientists supported by DOE's Office of High Energy Physics (HEP). One of six major science program offices within the DOE Office of Science, HEP is dedicated to supporting researchers in exploring the most fundamental questions about the nature of the universe.

Better answers to those questions could come after Endeavour delivers AMS to orbit. As Dr. Ting told The New York Times last November, "Real discovery is outside the ring of existing knowledge."

Endeavour's successful launch into a May morning sky stands as a testament to the quest of discovery, and a testimony to the power of endurance.

For more information on the DOE Office of Science, go to: http://www.science.energy.gov/. You can find the Office of High Energy Physics under "Programs."
For more information on the AMS Mission, go to: http://ams.cern.ch/External link
And for more information on the launch of the Space Shuttle Endeavor, please click to:
http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.htmlExternal link

Charles Rousseaux is a Senior Writer in the Office of Science

Last modified: 3/15/2013 5:23:51 PM