Wednesday, October 10, 2012

This dazzling image shows the globular cluster Messier 69, or M 69 for short, as viewed through the NASA/ESA Hubble Space Telescope. Globular clusters are dense collections of old stars. In this picture, foreground stars look big and golden when set against the backdrop of the thousands of white, silvery stars that make up M 69.

Another aspect of M 69 lends itself to the bejeweled metaphor: As globular clusters go, M 69 is one of the most metal-rich on record. In astronomy, the term "metal" has a specialized meaning: it refers to any element heavier than the two most common elements in our Universe, hydrogen and helium. The nuclear fusion that powers stars created all of the metallic elements in nature, from the calcium in our bones to the carbon in diamonds. Successive generations of stars have built up the metallic abundances we see today.

Because the stars in globular clusters are ancient, their metallic abundances are much lower than more recently formed stars, such as the Sun. Studying the makeup of stars in globular clusters like M 69 has helped astronomers trace back the evolution of the cosmos.

M 69 is located 29 700 light-years away in the constellation Sagittarius (the Archer). The famed French comet hunter Charles Messier added M 69 to his catalogue in 1780. It is also known as NGC 6637.

The image is a combination of exposures taken in visible and near-infrared light by Hubble’s Advanced Camera for Surveys, and covers a field of view of approximately 3.4 by 3.4 arcminutes.

Wednesday, October 03, 2012

Blanketing NASA's Webb Telescope's Science Instrument Electronics

These engineers from Genesis Engineering Solutions are doing what’s called "blanket closeout" and it took two days to complete.

The gold louvers are composite mirrors, made of gold-coated carbon fiber, designed to remove the heat from inside the IEC to deep space. 

The IEC holds computing hardware for each of the science instruments. This special part of the telescope allows the computer hardware to operate at room temperature on the cold side of the telescope by directing heat away so that the telescope can deliver infrared imagery.

"As heat radiates off the panel that they are attached to, the mirrors focus it in a particular direction (namely, away from the telescope)," says Lutter. 

After the engineers completed blanketing, the IEC was then placed in the thermal chamber to be tested against the chill of a space-simulated environment. This process is called the thermal vacuum and balance test. During this test, temperatures drop to about 90 degrees Kelvin (-297.67 degrees Fahrenheit or -183.15 degrees Celsius). 

"This is important because we need to know how effective the IEC is at keeping heat away from the cold side of Webb," says Lutter. "If even a little heat escapes the IEC in the direction of the telescope, the telescope's sensitivity could be ruined."