A Primer on Jupiter’s Clouds →

Justin Cowart:

The most obvious features of Jupiter are its bands of light and dark clouds. These are bordered by jet streams blowing east and west. The light areas are called zones. The air inside zones is circulating anti-cyclonically, making them a broad area of higher air pressure. The increased pressure supports the formation of high-altitude clouds of white ammonia ice, which mostly obscure the deeper, more colorful clouds. The dark areas are called belts, and inside these the air circulates cyclonically. In the belts, the ammonia ice clouds aren’t thick enough to obscure the view, allowing us to see a deeper cloud deck of ammonium sulfide and ammonium hydrosulfide, as well as a rich brew of organic compounds. These chemicals could be giving the belts their brownish color.

STS-135 →

Bart Leahy, writing about the last space shuttle launch:

Five years ago today, the Space Shuttle Atlantis and the Space Shuttle program itself took its last flight into space on mission STS-135 to service the International Space Station (ISS). Since that last flight in 2011, the Shuttle orbiters have been flown off to museums across the country and NASA’s human spaceflight program has shifted to other missions and other vehicles. No other American human-rated spacecraft has been flown so often or accomplished so much.

The space shuttle wasn’t perfect, but the science done with it is stunning.

Juno powered by a PowerPC chip →

Like many past spacecraft, Jupiter’s new orbiter is powered by a PPC chip:

When you want radiation-hardened CPU designs (to guard against naughty things like cosmic rays flipping bits and zapping traces), you want BAE’s RAD series, and that means you want … PowerPC. Yes, Juno’s brain is a lowly RAD750 running at 200MHz, essentially a beige Power Mac G3 with cojones of pure lead. It has 128MB of the baddest, meanest, toughest DRAM there is and 256MB of flash on board with a system bus providing 100Mbps of instrument bandwidth for pure awesome.

Juno in Jupiter’s orbit →

Last night was an exciting one for space fans. Five years after launch, NASA’s Juno spacecraft entered orbit around Jupiter.

That isn’t a simple thing to accomplish. The spacecraft had to slow down enough to be captured by the planet’s gravity to swing around the gas giant. Slow down too much and the orbit would be too wide; miss the mark and the spacecraft could have met an early demise.

Here’s Phil Plat describing that process:

The engine burn was tense. 35 minutes is a long time for a spacecraft burn; after 20 minutes it had slowed Juno enough to be in orbit, but not the correct one. It had to continue for another 15 minutes to put the spacecraft on the correct orbit. It worked essentially perfectly. The burn time was off by just one second. That will have no real effect on the orbit.

Science isn’t starting today, though. Juno is currently in a highly elliptical orbit that will take 53 days to complete. On it’s return pass, the instruments will come on and readings will begin. After it’s second elliptical trip, (named a Perijove pass) there will be a second burn that will allow Juno to circle the gas giant from its north pole to its south every 14 days.

During these orbits, scientists hope to learn about Jupiter’s origins and much more.

This is an exciting time. Jupiter is a very hostile place, and Juno is only the second spacecraft dedicated to studying it. (Galileo was the first.) Knowing how Jupiter formed and more about it will help unlock the mysteries of not only our solar system, but of the whole universe.

Should be fun.

Juno →

On July 4, NASA’s Juno spacecraft will be inserted into orbit around Jupiter, the largest planet in our solar system.

For the first time, scientists will be able to see below the thick clouds that surround the gas giant. The craft is the farthest from Earth a solar-powered spacecraft has been used, and will travel around Jupiter in a polar orbit (as opposed to going around its equator) at 130,000 MPH. It’s orbit is elliptical, and is designed to allow the craft to image the entirety of Jupiter over its lifecycle.

Juno will circle Jupiter 37 times, and then be burned up in the planet’s atmosphere. The spacecraft will execute a close flyby above the planet’s cloud tops every 14 days during its 18 month mission.

The mission’s scientific objectives include learning about the makeup of the planet, its atmosphere and magnetosphere. It is theorized that Jupiter has a dense core, and by studying its gravitational and magnetic fields, it should be possible to learn more about the interior of the gas giant. Likewise the atmosphere and magnetosphere, the area around the planet where charged particles stream to and from the planet, will be studied in detail for the first time up close.

It’s an exciting mission. Jupiter dominates so much of the solar system due to its immense size and gravitational pull, and we really don’t know much about it. Juno should help change that.

Terrifying mission patches →

Loren Grush, writing about National Reconnaissance Office’s mission patches for various rocket launches to put … secret things … into orbit:

Well it turns out that releasing creepy AF mission patches is a long-standing tradition for the NRO. It’s a far cry from the cheery NASA mission patches we’re used to. Instead, many of the NRO patches follow a specific formula: large scary animal grasps Earth.

Seriously, go look at these things. Yikes.