Dienstag, 10. November 2015 - 17:15 Uhr

Raumfahrt - Start von Brant IX Rakete mit PICTURE-B Nutzlast am 16.11.2015


PICTURE-B: Seeing Through the Glare
Have you ever looked directly at a bright light and been blinded?  If you look away from the light objects come into focus, but as you get closer to the light you can’t make out the items surrounding it.
Telescopes have the same problem when looking at stars.  The light from the stars make it difficult to see any objects close to the star, such as a planet.
A NASA suborbital sounding rocket launch on November 16 from the White Sands Missile Range in New Mexico carrying a payload from the University of Massachusetts Lowell may shed some light on the problem, or in this case dim the light.
The Planet Imaging Coronagraphic Technology Using a Reconfigurable Experimental Base (PICTURE-B) will look at the dusty ring around the star Epsilon Eridani and develop technologies needed to one day image Earth-like exoplanets.
Supriya Chakrabarti, mission principal investigator from the UMass Lowell Center for Space Science and Technology, said, “The reason these regions are difficult to image is the bright starlight overwhelms everything close to it. What the instrument does is to dim the light from the star – sort of like the Deluminator or put-outer in Harry Potter –which makes it easier for us to look at the region near the star. The optical design is rather complex.”
Epsilon Eridani is the third closest star visible to the unaided eye. Smaller than the sun, the approximately one billion year old star is a mere 10.5 light years from Earth.
Ewan Douglas, a project scientist from Boston University, said, “The study of extrasolar planets is one of the most exciting research endeavors of modern astrophysics. Most of these planets have been discovered through the radial velocity and transit measurement techniques. While the list of known planetary systems continues to grow, very few direct images of these systems have been taken in reflected light where many planets are brightest.”
“PICTURE will observe the planetary environment around Epsilon Eridani. It has been suggested that Epsilon Eridani contains at least one planet and several substantial dust disks. A dust ring, with characteristics similar to the Kuiper belt, was discovered around this star in 1998. Astronomers have inferred that colliding asteroids and shedding comets are producing another dusty debris ring, similar to our asteroid belt. Such a bright inner asteroid belt may obscure attempts to directly image dim planets in reflected light.” he said.
“The primary goal of the PICTURE mission is a measurement of the reflected light from the inner asteroid belt, which is important for the design of future space telescopes to image reflected light from exoplanets. If successful, this will be one of the first reflected light images of a dust belt orbiting a Sun-like star at a distance similar to that of our own asteroid belt,” according to Douglas, a graduate student working on the project with Chakrabarti and Christopher Mendillo, a research scientist at UMass Lowell.
The payload’s predecessor, PICTURE was flown on a NASA sounding rocket in October 2011. While not an overwhelming success due to technical issues, Chakrabarti said they were able to demonstrate flight worthiness and the fine pointing system, which is comparable to the Hubble Space Telescope.
Going back to the work bench, the team rebuilt the instrument and developed a new silicon carbide mirror to prepare PICTURE-B for launch.
Chakrabarti noted, “Besides characterizing the regions around a star, we will mature the technology necessary for future exoplanet studies, while training and providing hands-on experience for graduate and undergraduate students on a cutting-edge research endeavor.”
Douglas said, "PICTURE will also demonstrate in space several new technologies necessary to directly image exoplanets, a deformable mirror which corrects telescope aberrations, a nulling coronagraph which blocks starlight while transmitting light close to the star (equivalent to dimming a streetlight in order to see a firefly next to it), and lightweight silicon carbide optics.”
PICTURE-B will launch on a Black Brant IX sounding rocket at 2:30 a.m. EST (00:30 a.m. MST).  It is estimated to fly to a peak altitude of 147 miles before landing in White Sands, where it will be recovered.
The team is already working on PICTURE-C for a NASA scientific balloon flight in 2017. 
Chakrabarti said, “The balloon instrument will have two flights. In the first flight we will replace the telescope, but keep the rest of the payload. In the second flight, we use a different optical system called a Vector Vortex Coronagraph and a different detector called a microwave kinetic inductance detector.  The balloon will give us the opportunity to look at multiple targets and mature a different set of technologies.”
The rocket launch is supported through NASA’s Sounding Rocket Program at the Wallops Flight Facility in Virginia. NASA’s Heliophysics Division manages the sounding rocket program.
The PICTURE-B payload is integrated at the White Sands Missile Range.
Quelle: NASA

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