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  • richardmitnick 2:46 pm on September 6, 2014 Permalink | Reply
    Tags: , , , , NASA Blueshift,   

    From NASA Blueshift: “A Ride on SOFIA” 

    NASA Blueshift
    NASA Blueshift

    September 5, 2014
    Maggie Masetti

    This is a guest blog by astronomer Brian Williams

    NASA SOFIA

    A joint project between NASA and the German space agency (DLR), the Stratospheric Observatory for Infrared Astronomy, or SOFIA, is a bit of a departure from NASA’s traditional telescope fleet. Rather than flying in space, SOFIA features a 2.5-meter telescope implanted into the side of a modified Boeing 747SP. The telescope observes the cosmos in infrared wavelengths beyond what our eyes can see, and doing so requires getting above the water vapor in the atmosphere close to the Earth’s surface that absorbs infrared radiation. SOFIA accomplishes this by flying at around 40,000 feet, revealing a part of the spectrum that is inaccessible from the ground.

    In May, I had observations being done on SOFIA to observe a bright supernova that exploded a few years ago. The supernova, given the catalog number 2010jl, had been observed with Spitzer last year, where it was noted to be bright in the infrared, several years post-explosion. This is quite rare, and we were granted follow-up observations with SOFIA to observe at even longer wavelengths. By observing at various places in the spectrum, we can put better constraints on the source of the bright emission and determine what is special about this supernova that makes its surroundings glow brightly several years after exploding. As part of this, I got the chance to go on the observing flight on the night of May 5-6th. Here’s the story of the experience.

    NASA Spitzer Telescope
    NASA/Spitzer

    sj

    This composite image of UGC 5189A shows X-ray data from Chandra in purple and optical data from Hubble Space Telescope in red, green and blue. SN 2010jl is the very bright X-ray source near the top of the galaxy (X-ray image: NASA / CXC / Royal Military College of Canada / P. Chandra et al; Optical image: NASA / STScI)

    NASA Chandra Telescope
    NASA/Chandra

    NASA Hubble Telescope
    NASA/ESA Hubble

    SOFIA flies out of NASA’s Armstrong Flight Research Center in Palmdale, CA, about an hour north of Los Angeles. I arrived at Armstrong’s Hangar 703 early in the afternoon of the 5th. I had electronically requested temporary security access through my NASA badge to save myself paperwork at the gate. Crossing my fingers that everything had been filled out correctly, I held my badge up to the security scanner. The light changed from red to green, and I heard an electronic locking mechanism open. I was good to go. I met up with my contact person inside and met some of the other people who would be onboard the night’s flight: a group of half a dozen middle and high school teachers from across the country, chosen as part of SOFIA’s Airborne Astronomy Ambassadors Program.

    drive
    Driving up to the hangar that houses SOFIA, on the left. Credit: Brian Williams

    Up first at 3:00 was an airplane safety briefing required for anyone who had not flown on SOFIA before. I couldn’t help but wonder if this was really necessary. I fly roughly 50,000 miles a year… I think I know how to find the exits on a plane. That said, this hour long briefing was surprisingly useful and interesting. I learned that there’s a correct and incorrect way to use the sliderafts (hint: jump onto the slide, don’t sit) and don the life preservers. I held some of the equipment that you hear about in the pre-flight videos that we all ignore on commercial flights. I put on a portable oxygen mask (SOFIA is not laid out like a normal plane, having most of the seats removed for equipment, so the typical oxygen masks that fall from the overhead compartment are not on the aircraft). I even learned how to use the emergency escape ropes from a hatch on top of the cockpit, which apparently are real things. They took us on a walk-through of the aircraft, pointing out where various important things are. Flashlights, fire extinguishers, life preservers, the like. They took us into the cockpit. They let me sit in the pilot’s seat. This wasn’t part of the safety briefing. I believe the safety officer said that no one had ever asked him that before, but he said it was fine, and it just goes to show what you can get if you ask for it.

    board
    Boarding the plane for the safety walkthrough. Credit: Brian Williams

    cockpit
    Me in the cockpit. I didn’t touch anything. Credit: Brian Williams

    brian
    I didn’t get to wear this jacket during the flight, but I borrowed it for this pic. A few minutes before takeoff. Credit Brian Wiliams

    After a break for food, we met for the pre-flight mission briefing. This involved everyone who would be on the flight that night, as well as a few support staff on the ground. The flight personnel that night consisted of two pilots and a flight engineer upstairs in the cockpit, a lead and assistant mission director, two instrument scientists, two telescope operators, three German scientists from DLR who were monitoring the telescope operation for an upcoming servicing, a safety officer, the six teachers, and me. I’ve almost certainly forgotten someone, but that’s approximately correct. We went over the flight plan for the evening and got the latest updates on the weather and atmospheric conditions and the status of the instruments onboard. Everything looked great. As the only “guest scientist” on the flight, they asked me to say a few words about what we’d be observing that night. When it was over we headed out to the plane for the flight to begin. Wheels up at 7:05 pm PDT.

    test
    SOFIA on the tarmac, being prepped for flight. Credit: Brian Williams

    The flight lasted about ten hours, landing at 4:58 on the morning of May 6th. While SOFIA’s telescope has some flexibility in where it can point, it is still largely tied to a direction that is approximately perpendicular to the direction the plane is flying. Thus, what looks like a nonsensical route for a plane to fly is actually a carefully choreographed dance designed to place all the night’s targets within view. We started off flying northeast until we were over Colorado, then turned northwest to fly all the way up to British Columbia. We then backtracked to Montana, flew over North Dakota, then headed back northwest again to Alberta. Finally, we had a long, straight shot back to southern California for a landing. The flight itself drags on a bit over the course of the night after the initial excitement wears off. There are no in-flight movies or meals. There’s only so much you can chat with people after that many hours. They did allow us go up to the cockpit and hang out with the pilots, so that was neat. A few people napped. We weren’t awarded frequent flier miles, but it was still a great experience. Upon landing, the crew went home and the teachers went to their hotel. I took advantage of the crash-pad at Armstrong and slept for a few hours before driving back to LA to get on another plane and head home.

    take
    Brian, getting ready for takeoff. Credit: Brian Williams

    people
    Interior of the plane in flight, facing forward, showing some of the flight crew. Credit: Brian Williams

    view
    Shortly after takeoff, looking back at NASA’s Armstrong Research Center and the runway. Credit: Brian Williams

    rear
    Facing the rear of the plane and the telescope. Credit: Brian Williams

    The data didn’t show a direct detection of supernova 2010jl, but all hope is not lost. We prepared for that possibility, and my colleagues and I are analyzing the data to see if useful upper limits can be extracted from the data. Much like the curious case of the dog that didn’t bark, sometimes not seeing a thing can tell you as much about it as if you had seen it, if you can figure out why it isn’t there. A negative signal may imply that the type of dust that is present around this supernova doesn’t emit much light at the longer wavelengths that SOFIA observes at. It may also mean that the overall brightness has faded over the course of a few months. Follow-up observations with other instruments and theoretical modeling of the emission that we see and don’t see will allow us to answer these questions.

    See the full article here.

    Blueshift is produced by a team of contributors in the Astrophysics Science Division at Goddard. Started in 2007, Blueshift came from our desire to make the fascinating stuff going on here every day accessible to the outside world.

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  • richardmitnick 7:52 pm on May 1, 2014 Permalink | Reply
    Tags: , , , , NASA Blueshift   

    From Maggie’s Blog at NASA Blueshift: “[Maggie's blog] X-ray Detectors on the Move” 

    NASA Blueshift

    NASA Blueshift

    Here at NASA Goddard, in Astrophysics, we have quite a large group that studies high-energy light – that is X-rays and gamma-rays. Not only do our astrophysicists study the objects that emit light at these energies, some of them build the instruments to collect this astronomical data.

    One such astrophysicist is Dr. Rich Kelley. [Fun fact - he plays lead guitar in the Blueshift podcast theme song, which is primarily his composition.] His latest project is a Soft X-ray Spectrometer (SXS) on the joint US/Japanese satellite Astro-H, which is due to launch in 2015. Astro-H will explore the extreme universe that is abundant with high energy phenomena around black holes and supernova explosions, and observe clusters of galaxies filled with high-temperature plasma.

    astro h

    Illustration: Akihiro Ikeshita / JAXA

    The SXS is a system of X-ray calorimeters that sit behind an X-ray telescope. A calorimeter works by detecting tiny temperature changes. When an incoming X-ray is absorbed in the detector, the detector heats up a tiny, tiny amount. In order to detect such a small temperature difference, the detector must be very cold – it will run at 50 milli-Kelvins, or 50 thousandths of a degree above absolute zero. You can read more about how X-ray calorimeters work on the Collaboration website for Astro-H.

    The SXS just recently passed a big milestone when its detectors were shipped to Japan for integration and testing.

    I got the chance to see them, literally right before they put the shipping cover on. Rich gave me a little tour and I was able to snap this picture through the clean tent:

    maggie 1
    Credit: Maggie Masetti

    Rich gave us a few close-up images of the hardware, which Kevin Boyce, systems engineer and sometime Blueshift blogger, captioned for us. [Second fun fact: Kevin plays bass on the Blueshift podcast theme song. Ok, full disclosure - Rich, Kevin and I play in a band together.]

    da
    Credit: NASA

    Above you see the Detector Assembly (DA) and 3rd stage of the Adiabatic Demagnetization Refrigerator (ADR) that keeps the detectors at 50 milli-Kelvins. The detectors are just behind the center of the circular plate labeled Detector Assembly. The ADR has three stages, of which this is the warmest, running between 1.5 and 4.5 Kelvins. The other two stages are on the other side of the mounting plate, and can be seen in the photo below. An ADR consists of a superconducting magnet, a slug of ferromagnetic salt (the “salt pill”), and one or more heat switches. The magnet and salt pill are inside the area marked as “ADR”.

    nasa
    Credit: NASA

    Above is the bottom of their subsystem. Here you can see the magnets for Stage 1 and Stage 2 of the ADR. Actually what you see is magnetic shielding. It is important to keep the very high magnetic fields contained within our instrument, so as not to confuse the geomagnetic sensor (essentially a compass) on the spacecraft. Therefore we have this shielding. The suspension systems are also marked. Each of these is a set of Kevlar strings that support the salt pill within the magnet. This is used to thermally isolate the salt pill from the much hotter surroundings. For instance, in Stage 1 the salt pill runs at 50 mK, while the surroundings are about 1.2 K (24 times hotter; that’s a bigger ratio than between our body temperature and the surface of the sun).

    nasa 2
    Credit: NASA

    Above is other view of the DA and ADR 3rd stage. The detector output wires are marked. All other wires you see are either current supply to the superconducting magnets or thermometer wires. There are 44 thermometers in the system, so we can measure temperature in many different places. Also visible in this photo is a temporary protective cap, made of a small aluminum parts tray and tape, to protect the X-ray filter from damage. The filters allow X-rays through, but not visible light, ultraviolet, infrared, or radio waves. They are very delicate; you can break them by breathing on them.

    We’ll keep you updated on this cool (literally!) mission – we wish them the best!

    See the full article here.

    Blueshift is produced by a team of contributors in the Astrophysics Science Division at Goddard. Started in 2007, Blueshift came from our desire to make the fascinating stuff going on here every day accessible to the outside world.

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  • richardmitnick 8:12 pm on April 18, 2014 Permalink | Reply
    Tags: , , , , NASA Blueshift,   

    From NASA/Blueshift: “[Maggie's Blog] A Secondary Space Mirror” 

    NASA Blueshift

    April 18, 2014
    Maggie Masetti

    One of the cool things about the James Webb Space Telescope’s design is the giant boom that sticks out in front of the telescope. This structure is what holds the telescope’s secondary mirror. It’s the “small” round gold thing, visible in this artist’s conception.

    boom
    Credit: NASA

    Here’s what it looks like for real. This is the flight mirror, the one that is going into space! It’s coated in gold like JWST’s other mirrors to optimize it for reflecting infrared light.

    men
    Credit: NASA/Chris Gunn

    It’s actually pretty big – in fact it’s not much smaller than the Spitzer Space Telescope’s primary mirror! (Spitzer’s primary mirror is 0.85 meters in diameter, JWST’s secondary mirror is 0.74 meters.) It just looks small next to JWST’s 21 foot diameter primary mirror!

    stacks
    Credit: NASA

    Northrop Grumman has the pathfinder, or test version of this boom structure that will hold the secondary mirror.

    ng
    Credit: Paul Geithner

    I found out a little more about it from Deputy Project Manager for JWST, Paul Geithner, and Optical Telescope Element Manager, Lee Feinberg. Here’s their caption for the above photo.

    This is the secondary mirror structure (SMSS) for the Pathfinder telescope structure. The flight one will be virtually identical. This image is from a ‘walkout’ of the structure from its stowed to its deployed condition. The scale is evident in the photo, comparing the people and the structure. This walkout involved careful offloading of weight in the 1g environment on Earth; this deployment will take place in space where there is the inertia of the mass but not the weight, and ground deployments require offloading. The flight SMSS is in strength testing, and it will be integrated with the backplane before it is sent to NASA Goddard for telescope assembly.

    Before this, the Pathfinder telescope backplane and SMSS will come to Goddard for ‘pathfinding’ operations as practice for the integration we will do on the flight in 2015. Once at Goddard, two spare primary mirror segments and a spare secondary will be installed to make up the Pathfinder telescope.

    This is the first time a deployable secondary mirror structure for a space telescope has ever been tested. The SMSS is over 8 meters (26.2 feet) tall.

    Here is the Northrop Grumman Integration and Test team after successfully transferring the pathfinder SMSS from the floor assembly jig (that tall, black, latticed structure you see in the other photo) to the backplane pathfinder.

    team
    Credit: Northrop Grumman

    We’ll be sure to give a report when this huge structure shows up at NASA Goddard – we’ll be excited to see it for ourselves!

    See the full article here.

    Blueshift is produced by a team of contributors in the Astrophysics Science Division at Goddard. Started in 2007, Blueshift came from our desire to make the fascinating stuff going on here every day accessible to the outside world.

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  • richardmitnick 7:52 am on February 15, 2014 Permalink | Reply
    Tags: , , , , NASA Blueshift   

    From NASA/BlueShift: “Happy Valentine’s Day!” 

    NASA Blueshift

    February 14, 2014
    Maggie Masetti

    Happy Valentine’s Day from NASA Blueshift. We spotted this image go by on social media this morning and Rick Wiggins was kind enough to grant us permission to repost it. This is the Heart Nebula, or IC 1805. It’s about 7500 light years away from Earth, and can be located in the constellation Cassiopeia. The nebula actually sits in the Perseus arm of our galaxy, while the Sun is nearby (astronomically speaking, anyway) in the Orion Arm.

    heart

    This nebula, made of dusty dark clouds and hot glowing gas, has a cluster of newborn stars near “heart” center, called Melotte 15.

    [The Heart Nebula, IC 1805, Sh2-190, lies some 7500 light years away from Earth and is located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. This is an emission nebula showing glowing gas and darker dust lanes. The nebula is formed by plasma of ionized hydrogen and free electrons. Wikipedia]

    milky way
    Observed structure of the Milky Way’s spiral arms.

    See the full article here.

    Blueshift is produced by a team of contributors in the Astrophysics Science Division at Goddard. Started in 2007, Blueshift came from our desire to make the fascinating stuff going on here every day accessible to the outside world.

    NASANASA Goddard Banner


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