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Credit: NASA/Michael Lentz

NASA’s space balloon will float a telescope up there to spy on the secret lives of stars

Contributed by
Jul 27, 2020

Do you ever wonder where balloons go when they are left to float out of sight? Wherever they end up, NASA’s newest balloon mission is going somewhere cooler than that.

This isn’t just some random carnival balloon that escaped. It will be carrying the space agency’s ASTHROS (Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Submillimeter-Wavelengths) telescope, which is currently in development. ASTHROS will reveal even more secrets that stars are hiding by observing light at far-infrared wavelengths that are too long for the human eye to process. Earth’s atmosphere also blocks many of these wavelengths. To see what our vision cannot and the atmosphere forbids, the relatively small telescope will have to be lofted about 130,000 feet into the sky.

Just to give you an idea of how high that is, it’s four times higher than commercial airlines dare to venture.

But why float a balloon when you can blast off a rocket? It obviously costs less, because rockets need propellant, and not depending on propellant that will inevitably run out also extends the life of the mission. It also takes much less time to deploy a balloon launch after it has been planned out. NASA’s Scientific Balloon Program carries out proto-missions that could be a real expensive mistake if they end up malfunctioning in deep space and potentially failing. They can take risky missions high enough to be on the edge of space but still close enough to Earth to work out any glitchy tech or anything else that doesn’t operate as expected before the final version is launched on a rocket and sent hurtling into the vacuum of space.

How NASA launches a space balloon. Credit: NASA

"Balloon missions like ASTHROS are higher-risk than space missions but yield high-rewards at modest cost," said ATHROS project manager Jose Siles, an engineer at NASA’s JPL (Jet Propulsion Lab). "With ASTHROS, we're aiming to do astrophysics observations that have never been attempted before. The mission will pave the way for future space missions by testing new technologies and providing training for the next generation of engineers and scientists."

The balloon that will carry ASTHROS is going to be about 400 feet wide when full inflated. That’s basically a floating football stadium. It is scheduled to launch from Antarctica in 2023, since the freezing temperatures will keep the instruments in its solar-powerd cryocooler safe. Riding in the gondola attached to the balloon will be the 8.4-foot telescope, along with various hypsersensitive instruments such as mirrors lenses and detectors that can see infrared light where human eyes fail. From the home planet, scientists will be able to manipulate the telescope to point exactly where they need it to and use satellite links to download any data ASTHROS beams back in real time.

ASTHROS will seek out and map two types of nitrogen ions, or charged atoms that do not have an equal amount of electrons and protons. Ions can be negative or positive depending on whether they have more or fewer electrons than protons, but the most important thing about these particular ions is that may be proof of star-forming regions. They are believed to be a by-product of star formation and destruction known as stellar feedback. Stars are born violently and usually die violently. Jets of ionized gas rush out as they form, and the powerful winds of their death throes as they go supernova scatter ions that either get in the way of star formation or accrete into new stars.

These ions could tell us more about stellar feedback, which can influence future simulations of galactic evolution. They can also indicate where stars are forming in the Milky Way, and 3D maps of how gas behaves in star-forming zones will show how newborn stars influence the star stuff around them. If ASTHROS can find these ions and map them, it will be a first.

The galaxy Messier 83, or M83, which ASTHROS will be checking out. Credit: NASA

"Computer simulations of galaxy evolution still can't quite replicate the reality that we see out in the cosmos. The nitrogen mapping that we'll do with ASTHROS has never been done before, and it will be exciting to see how that information helps make those models more accurate,” said JPL scientist and ASTHROS principal investigator Jorge Pineda

ASTHROS will also search the galaxy Messier 83 to find out how stellar feedback affects various galaxy types, and also zero in on the star TW Hydrae, which exists in a huge gaseous disc that could mean other stars are forming. Measuring the mass distribution of this disc could give away where dust and gas are clumping up to potentially form new stars.

Remember that next time you see a loose balloon drifting towards eternity.

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