LDB

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LDB: Long Duration Balloon



One of the major scientific opportunities down here is the Long Duration Balloon facility. Each year, two or three groups of scientists get the opportunity to send their project up into the atmosphere, attached to a helium balloon that is blown around the continent by steady winds at high altitudes for up to 40 days.


the uninflated balloon is unrolled onto the snow. It is so delicate, once it is unrolled, it must be inflated- no going back!

The balloon is a thin polyethylene material, about the same thickness as ordinary sandwich wrap. It is only partially inflated on the ground: once it reaches cruising altitude, it expands to a diameter of around 450 feet! These balloons fly at an altitude of between 123,000 and 131,000 feet (that's almost 25 miles high!). At the end of the 40-odd days it spends in the upper atmosphere, the multi-ton payload will be cut from the balloon remotely, and (hopefully!) drop back down to earth someplace close enough for the scientists to recover it.

The three projects that are flying this year are:

ATIC- Advanced Thin Ionization Calorimeter
CREAM- Cosmic Ray Energetics and Mass
BESS- Balloon-borne Experiment with a Superconducting Spectrometer

So what is everyone studying?

Both ATIC and CREAM are studying similar things; both are detecting high energy cosmic ray elements in order to answer a few questions, such as:

How do cosmic rays gain their enormous energies?
Are Supernova Remnants the site of particle acceleration?
Is there evidence for more than one cosmic accelerator?
How do high energy particles move through the galaxy?
(as postulated on the ATIC website)

So what are cosmic rays, and why are they interesting? The hypothesis from both of these experiments, as far as I understand them, is that cosmic rays originate from and are accelerated by supernovas. The ATIC website has an excellent explanation (which I could quote here, but this post would get way too long! besides, they have an interesting website). If you're into the science, the website has a good explanation of what their "payload" (the physical aparatus that hangs from the balloon) consists of.


the payload for each experiment is brought out to the snowy launch pack on the back of a specialized truck

They payload for the CREAM project uses a different mechanism to detect these cosmic rays, which is explained at the CREAM website.

The BESS project is searching for antimatter, which is among the rarest and most elusive types of particles in the Universe. The scientists are trying to understand the origin of cosmic antimatter and to find evidence for the existence of Hawking radiation from "evaporating" black holes, a theory proposed by Stephen Hawking. The BESS website is not very useful, but an informative article about one of their previous flights (same project) can be found here.

I hear its a big deal to get to fly (float?) an experiment here- there is a long waiting list. The advantage of flying a balloon-borne experiment here versus any other place in the world is that the balloon simply circles the continent and is therefore easy to recover, and access to other countries' airspace is not necessary (I guess there has been issues getting permission to fly over countries like Russia).

All three balloons are now in the air. CREAM, the first balloon to go up, has already circumnavigated the continent once. You can follow all three balloons around Antarctica with this real-time website- pretty cool. That site also has a chart of balloon flight altitude- pretty cool stuff!

Here are some great photos of the LDB launches. I was never free to watch the launches from close up, but for two of the launches, I just happened to be driving a shuttle out towards Willy Field (where the LDB headquarters are located)! So some of these are my photos, and some have been taken by others.


the balloon is being inflated with helium


the balloon is let go, deforming slightly as it rises


floating up....


up....


and away!


beautiful, isn't it?

In the upper atmosphere, the helium will expand the balloon to an enormous round ball- filling it to the red portion of the "cord" hanging below the balloon in the pictures!