Here’s a video of yesterday’s House hearing on astrobiology:
Caption:
On December 4, 2013, the House Committee on Science, Space and Technology held a hearing titled, “Astrobiology: Search for Biosignatures in our Solar System and Beyond.”
Invited witnesses were:
Dr. Mary Voytek
Senior Scientist for Astrobiology, Planetary Science Division
National Aeronautics and Space Administration
Dr. Sara Seager
Class of 1941 Professor of Physics and Planetary Science
Massachusetts Institute of Technology
Dr. Steven Dick
Baruch S. Blumberg Chair of Astrobiology, John W. Kluge Center
Library of Congress
The event was webcast live and is in the public domain.
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Lifeboat Foundation’s Response to NASA’s Asteroid Initiative Public Engagement Request
Kevin Berry, Legendary Projects
You can suggest topics for the panel to focus on:
How can Mars human space settlement advocacy be better? That’s a question you can answer as part of SpaceSoc’s Mars4U roundtable at the Dupont Summit – also live online – on Science, Technology, and Environmental Policy on Dec 6 in Washington, DC, USA. The Dupont Summit is an annual conference of the Policy Studies Organization (PSO), an affiliate of the American Political Science Association and International Political Science Association. PSO bridges political research with political practice.
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.
This colorful view from NASA’s Cassini mission is the highest-resolution view of the unique six-sided jet stream at Saturn’s north pole known as “the hexagon.”
NASA’s Cassini spacecraft has obtained the highest-resolution movie yet of a unique six-sided jet stream, known as the hexagon, around Saturn’s north pole.
This is the first hexagon movie of its kind, using color filters, and the first to show a complete view of the top of Saturn down to about 70 degrees latitude. Spanning about 20,000 miles (30,000 kilometers) across, the hexagon is a wavy jet stream of 200-mile-per-hour winds (about 322 kilometers per hour) with a massive, rotating storm at the center. There is no weather feature exactly, consistently like this anywhere else in the solar system.
“The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable,” said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. “A hurricane on Earth typically lasts a week, but this has been here for decades — and who knows — maybe centuries.”
Weather patterns on Earth are interrupted when they encounter friction from landforms or ice caps. Scientists suspect the stability of the hexagon has something to do with the lack of solid landforms on Saturn, which is essentially a giant ball of gas.
