Category Archives: Astronomy

Astronomy, Eyes in the Sky, Science and Technology

DARPA project demonstrates imaging with lightweight membrane optics suitable for large space telescopes

Perhaps this technology will be suitable for making telescopes large enough to resolve exoplanets:

First Folding Space Telescope Aims to “Break the Glass Ceiling” of Traditional Designs

MOIRE program creates first-ever images using lightweight membrane optics,
which could help redefine how we build, launch and use orbital telescopes

The capability of orbital telescopes to see wide swaths of the earth at a time has made them indispensable for key national security responsibilities such as weather forecasting, reconnaissance and disaster response. Even as telescope design has advanced, however, one aspect has remained constant since Galileo: using glass for lenses and mirrors, also known as optics. High-resolution imagery traditionally has required large-diameter glass mirrors, which are thick, heavy, difficult to make and expensive. As the need for higher-resolution orbital imagery expands, glass mirrors are fast approaching the point where they will be too large, heavy and costly for even the largest of today’s rockets to carry to orbit.

DARPA’s Membrane Optical Imager for Real-Time Exploitation (MOIRE) program seeks to address these challenges. MOIRE aims to create technologies that would enable future high-resolution orbital telescopes to provide real-time video and images of the Earth from Geosynchronous Earth Orbit (GEO)—roughly 22,000 miles above the planet’s surface. Size and cost constraints have so far prevented placing large-scale imaging satellites in GEO, so MOIRE is developing technologies that would make orbital telescopes much lighter, more transportable and more cost-effective.

Currently in its second and final phase, the program recently successfully demonstrated a ground-based prototype that incorporated several critical technologies, including new lightweight polymer membrane optics to replace glass mirrors. Membrane optics traditionally have been too inefficient to use in telescope optics. MOIRE has achieved a technological first for membrane optics by nearly doubling their efficiency, from 30 percent to 55 percent. The improved efficiency enabled MOIRE to take the first images ever with membrane optics.

While the membrane is less efficient than glass, which is nearly 90 percent efficient, its much lighter weight enables creating larger lenses that more than make up the difference. The membrane is also substantially lighter than glass. Based on the performance of the prototype, a new system incorporating MOIRE optics would come in at roughly one-seventh the weight of a traditional system of the same resolution and mass. As a proof of concept, the MOIRE prototype validates membrane optics as a viable technology for orbital telescopes.

“Membrane optics could enable us to fit much larger, higher-resolution telescopes in smaller and lighter packages,” said Lt. Col. Larry Gunn, DARPA program manager. “In that respect, we’re ‘breaking the glass ceiling’ that traditional materials impose on optics design. We’re hoping our research could also help greatly reduce overall costs and enable more timely deployment using smaller, less expensive launch vehicles.”

Instead of reflecting light with mirrors or refracting it with lenses, MOIRE’s membrane optics diffract light. Roughly the thickness of household plastic wrap, each membrane serves as a Fresnel lens—it is etched with circular concentric grooves like microscopically thin tree rings, with the grooves hundreds of microns across at the center down to only 4 microns at the outside edge. The diffractive pattern focuses light on a sensor that the satellite translates into an image.

MOIRE technology houses the membranes in thin metal “petals” that would launch in a tightly packed configuration roughly 20 feet in diameter. Upon reaching its destination orbit, a satellite would then unfold the petals to create the full-size multi-lens optics. The envisioned diameter of 20 meters (about 68 feet) would be the largest telescope optics ever made and dwarf the glass mirrors contained in the world’s most famous telescopes.

From GEO, it is believed, a satellite using MOIRE optics could see approximately 40 percent of the earth’s surface at once. The satellite would be able to focus on a 10 km-by-10 km area at 1-meter resolution, and provide real-time video at 1 frame per second.

Ball Aerospace and Technologies Company and the U.S. Air Force Academy are the prime contractors for Phase 2 of the MOIRE program.

Asteroids & Comets, Astronomy, Events

The ISON story continues

The latest on comet ISON:

NASA Investigating the Life of Comet ISON

After several days of continued observations, scientists continue to work to determine and to understand the fate of Comet ISON: There’s no doubt that the comet shrank in size considerably as it rounded the sun and there’s no doubt that something made it out on the other side to shoot back into space. The question remains as to whether the bright spot seen moving away from the sun was simply debris, or whether a small nucleus of the original ball of ice was still there. Regardless, it is likely that it is now only dust.

Comet ISON comes in from the bottom right and moves out toward the upper right, getting fainter and fainter.
Comet ISON comes in from the bottom right and moves out toward the upper right, getting fainter and fainter, in this time-lapse image from the ESA/NASA Solar and Heliospheric Observatory. The image of the sun at the center is from NASA’s Solar Dynamics Observatory. Image Credit: ESA/NASA/SOHO/SDO/GSFC

Comet ISON, which began its journey from the Oort Cloud some 3 million years ago, made its closest approach to the sun on Nov. 28, 2013. The comet was visible in instruments on NASA’s Solar Terrestrial Relations Observatory, or STEREO, and the joint European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, via images called coronagraphs. Coronagraphs block out the sun and a considerable distance around it, in order to better observe the dim structures in the sun’s atmosphere, the corona. As such, there was a period of several hours when the comet was obscured in these images, blocked from view along with the sun. During this period of time, NASA’s Solar Dynamics Observatory could not see the comet, leading many scientists to surmise that the comet had disintegrated completely. However, something did reappear in SOHO and STEREO coronagraphs some time later – though it was significantly less bright.

http://youtu.be/kcROVqmF9SY
Comet ISON is shown approaching the sun and curving away from it in this movie containing imagery from both NASA’s Solar Terrestrial Relations Observatory and the joint ESA/NASA Solar and Heliospheric Observatory from November 2013. ISON dims dramatically as it streams away from the sun.
Image Credit: ESA/NASA/SOHO/STEREO/GSFC

Whether that spot of light was merely a cloud of dust that once was a comet, or if it still had a nucleus – a small ball of its original, icy material – intact, is still unclear. It seems likely that as of Dec. 1, there was no nucleus left. By monitoring its changes in brightness over time, scientists can estimate whether there’s a nucleus or not, but our best chance at knowing for sure will be if the Hubble Space Telescope makes observations later in December 2013.

Regardless of its fate, Comet ISON did not disappoint researchers. Over the last year, observatories around the world and in space gathered one of the largest sets of comet observations of all time, which should provide fodder for study for years to come. The number of space-based, ground-based, and amateur observations were unprecedented, with twelve NASA space-based assets observing over the past year.

Related Links:

For more information on Comet ISON: www.nasa.gov/ison

To download recent ISON imagery: http://svs.gsfc.nasa.gov/Gallery/CometISON.html

Astronomy, Events, Solar Science

ISON – The die hard comet

4 Comments

Evidence is growing that a part of the Comet ISON nucleus did in fact survive its close solar experience (see previous posting). Here is a report from NASA:

Comet ISON May Have Survived

Continuing a history of surprising behavior, material from Comet ISON appeared on the other side of the sun on the evening on Nov. 28, 2013, despite not having been seen in observations during its closest approach to the sun.

This movie shows Comet ISON orbiting around the sun – represented by the white
circle — on Nov. 28, 2013. ISON looks smaller as it streams away, but scientists
believe its nucleus may still be intact. The video covers Nov. 27, 2013, 3:30 p.m. ET
to Nov. 29, 2013, 8:30 a.m. ET. Image Credit: ESA/NASA/SOHO/Jhelioviewer

As ISON appeared to dim and fizzle in several observatories and later could not be seen at all by NASA’s Solar Dynamics Observatory or by ground based solar observatories, many scientists believed it had disintegrated completely. However, a streak of bright material streaming away from the sun appeared in the European Space Agency and NASA’s Solar and Heliospheric Observatory later in the evening. The question remains whether it is merely debris from the comet, or if some portion of the comet’s nucleus survived, but late-night analysis from scientists with NASA’s Comet ISON Observing Campaign suggest that there is at least a small nucleus intact.

Three view of what's left of Comet ISON rounding the sun.
ISON appears as a white smear heading up and away from the sun. ISON was
not visible during its closest approach to the sun, so many scientists thought
it had disintegrated, but images like this one from the ESA/NASA Solar and
Heliospheric Observatory suggest that a small nucleus may be intact.
Image Credit: ESA/NASA/SOHO/GSFC
Continuing a history of surprising behavior, material from Comet ISON appeared on the other side of the sun on the evening on Nov. 28, 2013, despite not having been seen in observations during its closest approach to the sun.

As ISON appeared to dim and fizzle in several observatories and later could not be seen at all by NASA’s Solar Dynamics Observatory or by ground based solar observatories, many scientists believed it had disintegrated completely. However, a streak of bright material streaming away from the sun appeared in the European Space Agency and NASA’s Solar and Heliospheric Observatory later in the evening. The question remains whether it is merely debris from the comet, or if some portion of the comet’s nucleus survived, but late-night analysis from scientists with NASA’s Comet ISON Observing Campaign suggest that there is at least a small nucleus intact.

A bright ISON goes into the sun, a dim ISON comes out.
Another view from SOHO’s C2 chronograph shows Comet ISON appearing
bright as it streams toward the sun (right). it can be seen as a dim streak
heading upward and out in the left image. The comet may still be intact.
Image Credit: ESA/NASA/SOHO/Jhelioviewer

Throughout the year that researchers have watched Comet ISON – and especially during its final approach to the sun – the comet brightened and dimmed in unexpected ways.  Such brightness changes usually occur in response to material boiling off the comet, and different material will do so at different temperatures thus providing clues as to what the comet is made of.  Analyzing this pattern will help scientists understand the composition of ISON, which contains material assembled during the very formation of the solar system some 4.5 billion years ago.

Related Links:

For more information on Comet ISON: www.nasa.gov/ison

To download recent ISON imagery: http://svs.gsfc.nasa.gov/Gallery/CometISON.html

Astronomy, Events, Solar Science

Comet ISON swings around the sun [Update]

The Comet ISON  swung behind the Sun today. Initial reports were that it did not survive its close encounter with the big heat but others are now saying that there appears to be a small object that remains on the same trajectory. Will watch for updates.

[ Update 1:10 am Nov.29.13: It’s still unclear as to whether there is a substantial remnant of the ISON core remaining after the comet’s encounter with the sun or if there is just a fading dust cloud:

]

Here’s are some great images of  ISON taken from the SOHO spacecraft before it went around the sun:  Comet ISON Streams Toward the Sun – NASA

ISON approaches the Sun as seen from SOHO LASCO C3 (Nov 28, 2013)

NASA / ESA / SOHO / Emily Lakdawalla
ISON approaches the Sun as seen from SOHO LASCO C3 (Nov 28, 2013)

This animation contains 123 images captured by the SOHO spacecraft between November 26 at 21:20 UT and November 28 at 15:37 UT.

Comet ISON Streams Toward the Sun

 

Comet ISON moves ever closer to the sun in this image from ESA and NASA's Solar and Heliospheric Observatory captured at 9:30 a.m. EST on Nov. 28, 2013.

Latest updates at

Astronomy, Space Arts

“The Kepler Story” : The background of a one-man performance work about Johannes Kepler

Here is a SETI Institute Google Hangout discussion about the Kepler Story | California Academy of Sciences.

The work is described as follows:

As a one-man performance with dramatic supporting music and full dome visuals, the Morrison Planetarium in collaboration with Motion Institute presents The Kepler Story – an innovative, immersive performance piece about the life and story of 17th-century astronomer and mystic Johannes Kepler. The story of his life, including his discovery of the three laws of planetary motion which removed Earth once and for all from its position at the center of the Universe, took an even more dramatic turn when his mother was arrested for witchcraft and Kepler was forced to defend her. On the way to her trial, reading Galileo’s father’s book on harmony, Kepler experienced one of his greatest epiphanies about the harmony of the universe.

History, religion, passion and science intersect in this remarkable individual’s life with a performance in the Academy’s planetarium that has the capacity to elicit moments of transcendence as it enlivens your senses and stimulates your mind. We will explore Kepler’s unique capacity to integrate a worldview steeped in mysticism with a rigorous scientific perspective based on observation and experimentation.

The Kepler Story is produced by Motion Institute, a Bay Area nonprofit theater production company that offers audiences a singular view of current issues, presented in ways that are contemporary, unpredictable, and embedded in the narratives of their own lives. Written and directed by Nina Wise and performed by Norbert Weisser, a veteran film and stage actor, The Kepler Story integrates spectacular visuals developed by the Morrison Planetarium visualization studio and Toshi Anders Hoo, deeply moving music by composer and cellist Zoë Keating and sound design by Emmy Award winner Christopher Hedge.