Endeavour to arrive in California on September 20
August 8th, 2012
03:53 PM ET

Endeavour to arrive in California on September 20

After 25 missions in space, the shuttle Endeavour will make its way to its new home at the California Science Center in Los Angeles on September 20, center President Jeffrey Rudolph announced.

The shuttle will be ferried on a 747 NASA Shuttle Carrier Aircraft from Florida to Los Angeles International Airport. NASA will work on it at the airport. Then, on October 12, it will be driven approximately 13 miles at less than one mile per hour through the streets of Los Angeles and Inglewood to the California Science Center, just south of downtown. The plan is for the shuttle to arrive at the science center the night of October 13.

Mayor Antonio Villaraigosa says 212 streetlights will need to be removed for the shuttle's trip. He says the city is making every effort to reduce the number of trees that will need to be uprooted, but those that are will be replaced by twice as many. Since Endeavour is about 58 feet tall, all overhead utility lines will also need to be removed.

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Filed under: On Earth
Curiosity's New Home
August 8th, 2012
03:33 PM ET

Curiosity's New Home

"These are the first two full-resolution images of the Martian surface from the Navigation cameras on NASA's Curiosity rover, which are located on the rover's "head" or mast. The rim of Gale Crater can be seen in the distance beyond the pebbly ground.

The topography of the rim is very mountainous due to erosion. The ground seen in the middle shows low-relief scarps and plains. The foreground shows two distinct zones of excavation likely carved out by blasts from the rover's descent stage thrusters.

These are full-resolution images, 1024 by 1024 pixels in size."

Source: NASA

Filed under: Light up the screen • Mars
Fossils complicate human ancestor search
The skull of a possible human ancestor was reconstructed with a cranium found in 1972 and a lower jaw discovered more recently.
August 8th, 2012
01:00 PM ET

Fossils complicate human ancestor search

The family tree of humanity as we know it - Homo sapiens - isn't as straightforward as "one species gave way to another." New evidence suggests that at least two different Homo species lived in Kenya about 2 million years ago.

Scientists report in the journal Nature that they have linked recently discovered fossils with a controversial cranium found in 1972 in Kenya. They believe these new remnants belonged to the same species as the skull, which has been dubbed Homo rudolfensis. The study is led by prominent paleontologist Meave Leakey.

The Homo rudolfensis skull, found near Lake Turkana, has a bigger brain case and a flatter face than specimens of Homo habilis, the other species of the Homo genus that appears to have lived around that time. Homo habilis is thought to have been a toolmaker because its hand bones were found next to stone tools.

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Filed under: Human ancestors • On Earth
August 8th, 2012
07:30 AM ET

5 reasons to be excited about Curiosity

Editor's Note: James Wray is an assistant professor of Earth and atmospheric sciences at the Georgia Institute of Technology in Atlanta. He is a collaborator on the Curiosity science team, affiliated with the Sample Analysis at Mars investigation. His research explores the chemistry, mineralogy and geology of Martian rocks as records of environmental conditions throughout the planet’s history.

NASA’s newest adventure to Mars has begun!

The Mars Science Laboratory mission delivered the Curiosity rover to Gale Crater, and the Internet and Twitterverse are abuzz. But NASA has landed on Mars six times before and has returned more information from the red planet than from all other planets beyond Earth combined.

So what is all the fuss about? Everyone who has learned a little about Curiosity is excited for different reasons; here are a few of my own.

1. The landing system. The rover landed in a complicated process NASA has called “seven minutes of terror.” Even the engineers who planned this unprecedented sequence of maneuvers for reaching the surface admit that "it looks crazy," but it worked! And this is innovation with a purpose.

It started in the upper atmosphere, where the heat shield first began to slow the entering spacecraft. During this phase of their landings, Spirit and Opportunity were just along for the ride, but Curiosity actually steered her way through the upper atmosphere, firing thrusters to adjust course. This allowed much more precise targeting of a landing area only 4 by 12 miles (7 by 20 kilometers) across, roughly one-fifth the size of prior landing ellipses.

Without this landing mechanism, we could not have safely landed in Gale Crater, between its bowl-shaped crater walls and Mount Sharp rising from its center. Guided entry will be critical for future landings in other scientifically rich — but small - areas of Mars.

Another major innovation was the sky crane system for surface delivery. It’s a big change from the airbags that have cushioned the landings of past rovers, but Curiosity is just too heavy for airbags. The sky crane allowed this rover — and, hopefully, future missions — to carry some big, complex science instruments, including those described below.

2. The laser on its head. So, we landed in Gale Crater … now what?

Our Mars orbiters have shown us that some sedimentary layers in Gale have interacted with water in the past, a good first clue in Curiosity’s hunt for habitable environments. But how do we choose which particular rocks to approach on the surface?

Cameras will help, but to find the salt- and clay mineral-rich rocks that directed us to Gale, we need a way to survey composition from a distance. Past missions have shown that many Mars rocks are coated with dust, hiding their true compositions.

The laser on Curiosity’s ChemCam instrument is the perfect tool for blasting through this dust layer to reveal the chemistry of any rock within 25 feet (7 meters) of the rover. Some areas in Gale appear to have thicker dust cover than the alternative sites considered for Curiosity, so ChemCam is especially well-suited for exploring Gale.

3. Definitive mineralogy. Don’t confuse ChemCam with CheMin, another instrument that Curiosity is carrying to Mars for the very first time. While ChemCam will provide a first look at the chemical elements in a rock or soil, CheMin will show how those elements are arranged into minerals. It uses X-ray diffraction, a favorite technique of laboratory mineralogists.

Orbital remote sensing has shown us that some layers in Gale contain clays, but what else do they contain? Are they 50% clay or 5% clay? The answers, which CheMin can deliver, have major implications for the style and duration of water activity that formed the clays. Ditto for the sulfate salts detected from orbit in other layers of Mount Sharp.

4. The search for organic molecules. CheMin is one of two instruments that will analyze samples scooped from the soil or drilled from the rocks of Gale Crater; the other is SAM, short for Sample Analysis at Mars. SAM is a gas chromatograph/mass spectrometer, the first one sent to Mars since the 1976 Viking landers, and its highest-profile job is to search for organic molecules.

Viking didn’t find any (although this conclusion has recently been questioned), but SAM will heat samples to twice as high a temperature, allowing detection of even the most “stubborn” organics that Viking might have missed. SAM even has some unprecedented “wet chemistry” experiments that could detect still other types of organics. Life on Earth is built almost entirely of organic molecules, but they also rain into planetary atmospheres constantly aboard meteorites and comets.

So if SAM finds no organics, it would imply that something on Mars actively destroys them (or at least has done so sometime since Gale’s sediments were deposited up to 3.6 billion years ago). If organics are found, then studying their properties with SAM may be our first step in moving from “was Mars ever habitable” to “did Mars actually host life?”

5. Settling the methane question. SAM has another component bundled with its gas chromatograph/mass spectrometer: a tunable laser spectrometer. This instrument fills a tube with gas from the Martian atmosphere (or boiled off from drill samples) and bounces a laser beam through it dozens of times, then looks to see how much light the gas has absorbed from the beam.

There are two lasers, and they can be “tuned” to different wavelengths, allowing for different components of the gas to be studied. Methane is one of these. In case you’ve “tuned” out for the past nine years, methane has been reported in the atmosphere of Mars by several research groups, but the claims have all been controversial. It matters because on Earth, roughly 98% of our atmospheric methane is ultimately due to life … and even if Mars had produced it through a non-life mechanism (e.g., volcanic activity), it shouldn’t survive there for more than a few centuries.

So modern methane would imply an active Mars today, exciting no matter what its cause. While it’s possible that Mars’ methane emerges only from places far from Gale Crater, the winds should ultimately blow some of it Curiosity’s way, and SAM’s exquisite sensitivity should allow us to catch a whiff.

More Curiosity news: His other car is on Mars

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