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Plan: The United States Federal Government should fully fund and implement a space based infrared sensor in a Venus-like orbit for the purposes of asteroid detection
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Observation 2: Solvency
Putting an infrared sensor in a Venus-like orbit would increase detection methods by 180% and could detect PHO’s, which threaten Earth.
Bucknam and Gold in 08 [Mark and Robert “Survival” (00396338); Oct/Nov2008, Vol. 50 Issue 5, p141-156, 16p PN] [PHO - potentially hazardous object]
NASA analysed options for better detecting PHOs, ranging from continuing the current terrestrial-based Spaceguard Survey to putting visual or infrared sensors on satellites in space. The existing Spaceguard techniques have little to contribute to the expanded goal of detecting objects on the scale of 140m, and NASA estimates Spaceguard could only detect approximately 14% of the 140m-or-larger PHOs by 2020,10 well short of Congress’ goal of 90%. The addition of a ground-based telescope, such as the University of Hawaii’s planned Panoramic Survey Telescope and Rapid Response System (PanSTARRS 4)11 or the proposed Large Synoptic Survey Telescope (LSST),12 would boost the results to 75–85%, depending on whether NASA shared the telescope with another agency or supported building an additional copy of its own. The most efficient means of finding PHOs would be to place an infra- red sensor in a Venus-like orbit – that is, 0.7 astronomical units from the sun. By itself such a sensor system could find 90% of PHOs larger than 140m by 2020. Furthermore, a space-based infrared telescope would allow scientists to reduce the uncertainties in determining the size of PHOs to 20% from over 200% for optical telescopes.13 A factor-of-two uncertainty – the limit of accuracy with optical telescopes – equates to a factor-of-eight uncertainty in mass. Because the size and mass of a PHO are important characteristics for assess- ing the danger it could pose, the added performance of a space-based infrared telescope warrants serious consideration. Moreover, an infrared telescope in a Venus-like orbit could efficiently detect PHOs that primarily orbit between the Earth and the Sun; these are difficult to detect from Earth and, according to NASA, have a chance of being perturbed by gravity and becoming a threat. The cost of such a system is on the order of $1bn, and the harsh space environment would likely limit its useful life to around seven to ten years.14
Space based telescopes are key to successful detection-they can operate 24/7 and are more efficient
IRWIN I. SHAPIRO et al in 10,( Harvard-Smithsonian Center for Astrophysics, Chair FAITH VILAS, MMT Observatory at Mt. Hopkins, Arizona, Vice Chair MICHAEL A’HEARN, University of Maryland, College Park, Vice Chair ANDREW F. CHENG, Johns Hopkins University Applied Physics Laboratory FRANK CULBERTSON, JR., Orbital Sciences Corporation DAVID C. JEWITT, University of California, Los Angeles STEPHEN MACKWELL, Lunar and Planetary Institute H. JAY MELOSH, Purdue University JOSEPH H. ROTHENBERG, Universal Space Network, Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies Space Studies Board Aeronautics and Space Engineering Board Division on Engineering and Physical Sciences, THE NATIONAL ACADEMIES PRESS, http://www.fas.harvard.edu/~planets/sstewart/reprints/other/4_NEOReportDefending%20Planet%20Earth%20Prepub%202010.pdf)
The 2003 NASA SDT study concluded that an infrared space telescope is a powerful and efficient means of obtaining valuable and unique detection and characterization data on NEOs. The thermal infrared, which denotes wavelengths of light from about 5 to 10 microns, is the most efficient color regime for an NEO search. An orbiting infrared telescope that detects these wavelengths and has a mirror between 0.50 and 1 meter in diameter is sufficient to satisfy the goal of detecting 90 percent of potentially hazardous NEOs 140 meters in diameter or greater. Plus, locating an NEO-finding observatory internal to Earth’s orbit is preferable for identifying NEOs that are inside Earth’s orbit. Specific advantages to space-based observations include: • A space-based telescope can search for NEOs whose orbits are largely inside Earth’s orbit. These objects are difficult to find using a ground-based telescope as observations risk interference from the Sun when pointing to the areas of the sky being searched. • Thermal-infrared observations are immune to the bias affecting the detection of low-albedo objects in visible or near infrared light, by observing the thermal signal from the full image of the NEO, providing more accurate albedo measurements (see discussion above). • Space-based searches can be conducted above Earth’s atmosphere, eliminating the need to calibrate the effects introduced by the atmosphere on the light from an NEO. • Observations can be made 24 hrs/day.
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Early detection is key-the government will need years to decades of preparation to deflect an Earth-threatening asteroid.
IRWIN I. SHAPIRO et al in 10,( Harvard-Smithsonian Center for Astrophysics, Chair FAITH VILAS, MMT Observatory at Mt. Hopkins, Arizona, Vice Chair MICHAEL A’HEARN, University of Maryland, College Park, Vice Chair ANDREW F. CHENG, Johns Hopkins University Applied Physics Laboratory FRANK CULBERTSON, JR., Orbital Sciences Corporation DAVID C. JEWITT, University of California, Los Angeles STEPHEN MACKWELL, Lunar and Planetary Institute H. JAY MELOSH, Purdue University JOSEPH H. ROTHENBERG, Universal Space Network, Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies Space Studies Board Aeronautics and Space Engineering Board Division on Engineering and Physical Sciences, THE NATIONAL ACADEMIES PRESS, http://www.fas.harvard.edu/~planets/sstewart/reprints/other/4_NEOReportDefending%20Planet%20Earth%20Prepub%202010.pdf)
In contrast to other known natural hazards, there has been no significant loss of human life to impacts in historical times, due to the low frequency of major impacts and the higher probability of impact in unpopulated (notably the oceans) than populated regions. Unlike the other hazards in Table 2.2, the hazard statistics for NEOs are dominated by single events with potentially high fatalities separated by long time intervals. Should scientists identify a large life-threatening object on a collision course with Earth, tremendous public resources to mitigate the risk would almost certainly be brought to bear. However, options for effective mitigation become much more limited when threatening objects are identified with only months to years, rather than decades or centuries, before impact. Thus, one of the greatest elements of risk associated with NEOs is the public expectation that governments will protect them against any threat from NEOs, coupled with an unwillingness so far of governments and agencies to expend public funds in a concerted effort to identify, catalogue and characterize as many potentially dangerous NEOs as possible as long before a damaging impact event as feasible.
Long warning times allow successful deflection strategies-even large asteroids can be diverted
IRWIN I. SHAPIRO et al in 10,( Harvard-Smithsonian Center for Astrophysics, Chair FAITH VILAS, MMT Observatory at Mt. Hopkins, Arizona, Vice Chair MICHAEL A’HEARN, University of Maryland, College Park, Vice Chair ANDREW F. CHENG, Johns Hopkins University Applied Physics Laboratory FRANK CULBERTSON, JR., Orbital Sciences Corporation DAVID C. JEWITT, University of California, Los Angeles STEPHEN MACKWELL, Lunar and Planetary Institute H. JAY MELOSH, Purdue University JOSEPH H. ROTHENBERG, Universal Space Network, Committee to Review Near-Earth Object Surveys and Hazard Mitigation Strategies Space Studies Board Aeronautics and Space Engineering Board Division on Engineering and Physical Sciences, THE NATIONAL ACADEMIES PRESS, http://www.fas.harvard.edu/~planets/sstewart/reprints/other/4_NEOReportDefending%20Planet%20Earth%20Prepub%202010.pdf)\
With the same warning time of 40 years as discussed for the gravity tractor, one could launch a series of perhaps ten 10-ton impactors to divert the NEO 30 years before impact for NEOs of order ¾ km in diameter and even more than 1 km for very-low-density NEOs. For a 10-year warning time and a crash program to launch 10 spacecraft in say 4 or 5 years, it might be possible to prevent a collision with a ½- km NEO with the gravity tractor; new, heavy-lift launchers such as the Ares cargo launcher might allow delivering 5 times more massive impactors. Multiple impactors provide robustness against random failures and the opportunity to fine-tune the results by varying the number of impacts. Even a single impactor that could be launched within 6 months might change the orbit of a 100-meter NEO, the size that is near the upper limit for use only of civil defense, with a warning time of only 1 to 2 years. Finding: Kinetic impactors are adequate to prevent impacts on Earth by moderately sized NEOs (many hundreds of meters to 1 kilometer) with decades of advance warning. The concept has been demonstrated in space, but the result is sensitive to the properties of the NEO and requires further study.
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