Cosmicrays - Blog Posts

Measuring Cosmic Rays at the Edge of Space

It’s a bird!  It’s a plane!  It’s a… SuperTIGER?

No, that’s not the latest superhero spinoff movie - it’s an instrument launching soon from Antarctica! It’ll float on a giant balloon above 99.5% of the Earth’s atmosphere, measuring tiny particles called cosmic rays.

Right now, we have a team of several scientists and technicians from Washington University in St. Louis and NASA at McMurdo Station in Antarctica preparing for the launch of the Super Trans-Iron Galactic Element Recorder, which is called SuperTIGER for short. This is the second flight of this instrument, which last launched in Antarctica in 2012 and circled the continent for a record-breaking 55 days.  

SuperTIGER measures cosmic rays, which are itty-bitty pieces of atoms that are zinging through space at super-fast speeds up to nearly the speed of light. In particular, it studies galactic cosmic rays, which means they come from somewhere in our Milky Way galaxy, outside of our solar system.

Most cosmic rays are just an individual proton, the basic positively-charged building block of matter. But a rarer type of cosmic ray is a whole nucleus (or core) of an atom - a bundle of positively-charged protons and non-charged neutrons - that allows us to identify what element the cosmic ray is. Those rare cosmic-ray nuclei (that’s the plural of nucleus) can help us understand what happened many trillions of miles away to create this particle and send it speeding our way.

The cosmic rays we’re most interested in measuring with SuperTIGER are from elements heavier than iron, like copper and silver. These particles are created in some of the most dynamic and exciting events in the universe - such as exploding and colliding stars.

In fact, we’re especially interested in the cosmic rays created in the collision of two neutron stars, just like the event earlier this year that we saw through both light and gravitational waves. Adding the information from cosmic rays opens another window on these events, helping us understand more about how the material in the galaxy is created.

Why does SuperTIGER fly on a balloon?

While cosmic rays strike our planet harmlessly every day, most of them are blocked by the Earth’s atmosphere and magnetic field.  That means that scientists have to get far above Earth - on a balloon or spacecraft - to measure an accurate sample of galactic cosmic rays.  By flying on a balloon bigger than a football field, SuperTIGER can get to the edge of space to take these measurements.  

It’ll float for weeks at over 120,000 feet, which is nearly four times higher than you might fly in a commercial airplane. At the end of the flight, the instrument will return safely to the ice on a huge parachute. The team can recover the payload from its landing site, bring it back to the United States, repair or make changes to it, if needed, and fly it again another year!

There are also cosmic ray instruments on our International Space Station, such as ISS-CREAM and CALET, which each started their development on a series of balloons launched from Antarctica. The SuperTIGER team hopes to eventually take measurements from space, too.  

Why do we launch from Antarctica?

McMurdo Station is a hotspot for all sorts of science while it’s summer in the Southern Hemisphere (which is winter here in the United States), including scientific ballooning.  The circular wind patterns around the pole usually keep the balloon from going out over the ocean, making it easier to land and recover the instrument later. And the 24-hour daylight in the Antarctic summer keeps the balloon at a nearly constant height to get very long flights - it would go up and down if it had to experience the temperature changes of day and night. All of that sunlight shining on the instrument's array of solar cells also gives a continuous source of electricity to power everything.

Antarctica is an especially good place to fly a cosmic ray instrument like SuperTIGER. The Earth’s magnetic field blocks fewer cosmic rays at the poles, meaning that we can measure more particles as SuperTIGER circles around the South Pole than we would at NASA scientific ballooning sites closer to the Earth’s equator.  

The SuperTIGER team is hard at work preparing for launch right now - and their launch window opens soon! Follow @NASABlueshift for updates and opportunities to interact with our scientists on the ice.

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From Frozen Antarctica to the Cold Vacuum of Space

A new experiment that will collect tiny charged particles known as galactic cosmic rays will soon be added to the International Space Station. The Cosmic Ray Energetics And Mass for the International Space Station payload, nicknamed ISS-CREAM, will soon be installed in its new home on the Station’s Japanese Experiment Module Exposed Facility. ISS-CREAM will help scientists understand more about galactic cosmic rays and the processes that produce them.

Wait, what are cosmic rays?

Cosmic rays are pieces of atoms that move through space at nearly the speed of light. Galactic cosmic rays come from beyond our solar system. 

They provide us with direct samples of matter from distant places in our galaxy.

Why do these things go so fast?

Galactic cosmic rays have been sped up by extreme processes. When massive stars die, they explode as supernovas. The explosion’s blast wave expands into space along with a cloud of debris. 

Particles caught up in this blast wave can bounce around in it and slowly pick up speed. Eventually they move so fast they can escape the blast wave and race away as a cosmic ray.

Where can we catch cosmic rays?

Cosmic rays are constantly zipping through space at these super-fast speeds, running into whatever is in their path -- including Earth.  

But Earth’s atmosphere is a great shield, protecting us from 99.9 percent of the radiation coming from space, including most cosmic rays.  This is good news for life on Earth, but bad news for scientists studying cosmic rays.  

So… how do you deal with that?

Because Earth has such an effective shield against cosmic rays, the best place for scientists to study them is above our atmosphere -- in space.  Since the 1920s, scientists have tried to get their instruments as close to space as possible. One of the simplest ways to do this is to send these instruments up on balloons the size of football stadiums. These balloons are so large because they have to be able to both lift their own weight and that of their cargo, which can be heavier than a car. Scientific balloons fly to 120,000 feet or more above the ground -- that’s at least three times higher than you might fly in a commercial airplane!  

Credit: Isaac Mognet (Pennsylvania State University)

Earlier versions of ISS-CREAM’s instruments were launched on these giant balloons from McMurdo Station in Antarctica seven times, starting in 2004, for a total of 191 days near the top of the atmosphere.  Each of these flights helped the team test their hardware and work towards sending a cutting-edge cosmic ray detector into space!  

How is going to space different than flying balloons?

Balloon flights allowed the team to collect a lot of cosmic rays, but even at 120,000 feet, a lot of the particles are still blocked. Scientists at the University of Maryland, College Park, who operate ISS-CREAM, expect to get about 10 times as much data from their new home on the International Space Station. 

That’s because it will be both above the atmosphere and fly far longer than is possible with a balloon. As you might imagine, there are large differences between flying something on a balloon and launching it into space. The science instruments and other systems had to be changed so ISS-CREAM could safely launch on a rocket and work in space.

What will ISS-CREAM do?

While on the space station, ISS-CREAM will collect millions of cosmic rays -- electrons, protons and atomic nuclei representing the elements found in the solar system. These results will help us understand why cosmic rays reach the wicked-fast speeds they do and, most important, what limits those speeds.

ISS-CREAM launches to the International Space Station aboard the latest SpaceX Dragon spacecraft, targeted to launch August 14. Want to learn more about ISS-CREAM and some of our scientific balloons? Check out our recent feature, NASA’s Scientific Balloon Program Reaches New Heights.

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