Gentle Spring (pre 1865). Frederick Sandys (English, 1829-1904). Oil On Canvas. The Ashmolean Museum

An Epitaph for Agamemnon

Ausonius, Epitaphia heroum qui bello Troico interfuerunt I: “Agamemnoni” I – the king of kings, Atreus’ son, Avenger of my brother’s wife – I met My death myself at my own wife’s hands. What profit does it give me to have punished, In my pain, the theft of Helen – when I, who sought to make adulterers pay, Lie slain by the hand of Clytemnestra? Rex regum Atrides, fraternae coniugis ultor,     oppetii manibus coniugis ipse meae. quid prodest Helenes raptum punisse dolentem,     vindicem adulterii cum Clytemestra necet?

Clytemnestra and Agamemnon, Pierre-Narcisse Guérin, ca. 1822

The Altar of Hymen by Edward Burne-Jones, circa 1874

Mars in a Box: How a Metal Chamber on Earth Helps us do Experiments on Mars

Inside this metal box, it’s punishingly cold. The air is unbreathable. The pressure is so low, you’d inflate like a balloon. This metal chamber is essentially Mars in a box — or a near-perfect replica of the Martian environment. This box allows scientists to practice chemistry experiments on Earth before programming NASA’s Curiosity rover to carry them out on Mars. In some cases, scientists use this chamber to duplicate experiments from Mars to better understand the results. This is what’s happening today.

The ladder is set so an engineer can climb to the top of the chamber to drop in a pinch of lab-made Martian rock. A team of scientists is trying to duplicate one of Curiosity’s first experiments to settle some open questions about the origin of certain organic compounds the rover found in Gale Crater on Mars. Today’s sample will be dropped for chemical analysis into a tiny lab inside the chamber known as SAM, which stands for Sample Analysis at Mars. Another SAM lab is on Mars, inside the belly of Curiosity. The SAM lab analyzes rock and soil samples in search of organic matter, which on Earth is usually associated with life. Mars-in-a-box is kept at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

This is Goddard engineer Ariel Siguelnitzky. He is showing how far he has to drop the sample, from the top of the test chamber to the sample collection cup, a small capsule about half an inch (1 centimeter) tall (pictured right below). On Mars, there are no engineers like Siguelnitzky, so Curiosity’s arm drops soil and rock powder through small funnels on its deck. In the photo, Siguelnitzky’s right hand is pointing to a model of the tiny lab, which is about the size of a microwave. SAM will heat the soil to 1,800 degrees Fahrenheit (1,000 degrees Celsius) to extract the gases inside and reveal the chemical elements the soil is made of. It takes about 30 minutes for the oven to reach that super high temperature.

Each new sample is dropped into one of the white cups set into a carousel inside SAM. There are 74 tiny cups. Inside Curiosity’s SAM lab, the cups are made of quartz glass or metal. After a cup is filled, it’s lifted into an oven inside SAM for heating and analysis.

Amy McAdam, a NASA Goddard geochemist, hands Siguelnitzky the sample. Members of the SAM team made it in the lab using Earthly ingredients that duplicate Martian rock powder. The powder is wrapped in a nickel capsule (see photo below) to protect the sample cups so they can be reused many times. On Mars, there’s no nickel capsule around the sample, which means the sample cups there can’t be reused very much.

SAM needs as little as 45 milligrams of soil or rock powder to reveal the secrets locked in minerals and organic matter on the surface of Mars and in its atmosphere. That’s smaller than a baby aspirin!

Siguelnitzky has pressurized the chamber – raised the air pressure to match that of Earth – in order to open the hatch on top of the Mars box.

Now, he will carefully insert the sample into SAM through one of the two small openings below the hatch. They’re about 1.5 inches (3.8 centimeters) across, the same as on Curiosity. Siguelnitzky will use a special tool to carefully insert the sample capsule about two feet down to the sample cup in the carousel.

Sample drop.

NASA Goddard scientist Samuel Teinturier is reviewing the chemical data, shown in the graphs, coming in from SAM inside Mars-in-a-box. He’s looking to see if the lab-made rock powder shows similar chemical signals to those seen during an earlier experiment on Mars.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

. . . Y después de una taza de té, sigo pensando en cómo olvidarte. Teddy GleZ.

J.E. Larson

Marguerite Gérard (French, 1761 - 1837): The reading of the gazette (via Sotheby’s)

autumn