Scale versions of 3D printed asteroid models and other planetary bodies are now being used by the ESA for real-life testing of spacecraft navigation and landing systems – martian moon Phobos seen in the foreground here.
“The models are based on accurate digital elevation model data gathered from past space missions,” explains Olivier Dubois-Matra of ESA’s Guidance, Navigation and Control Section. We then add color and surface finishing. Asteroids and comets do tend to be very dark – the images usually seen have been lightened and enhanced to reveal detail.”
Mobile cameras manouver around a model – to give the equivalent of a spacecraft’s eye-view – enabling the real-world testing of guidance and landing software and systems, which are often based on the mapping of surface features. Such physical testing can be carried out in parallel to virtual testing, such as that carried out using the dedicated ‘Planetary and Asteroid Natural scene Generation Utility’ or Pangu software.
Last June 30th was international Asteroid Day. In the US, spreading the word on the tiny bodies that Earth shares space with, as both a scientific resource and a potential danger is the job of NASA’s Planetary Defense Coordination Office. The PDCO is managed in the Planetary Science Division of the Science Mission Directorate at NASA Headquarters in Washington, D.C.
Ensuring the early detection of potentially hazardous objects (PHOs) – asteroids and comets whose orbits are predicted to bring them within 0.05 Astronomical Units of Earth; and of a size large enough to reach Earth’s surface – that is, greater than approximately 30 to 50 meters;
Tracking and characterizing PHOs and issuing warnings about potential impacts;
Providing timely and accurate communications about PHOs; and
Leading the coordination of U.S. Government planning for response to an actual impact threat.
The PDCO relies on data from projects supported by NASA’s Near-Earth Object (NEO) Observations Program. The PDCO also coordinates NEO observation efforts conducted at ground-based observatories sponsored by the National Science Foundation and space situational awareness facilities of the United States Air Force. In addition to finding, tracking, and characterizing PHOs, NASA’s planetary defense goals include developing techniques for deflecting or redirecting PHOs, if possible, that are determined to be on an impact course with Earth. In the event that deflection or redirection is not possible, the PDCO is responsible for providing expert input to the Federal Emergency Management Agency for emergency response operations should a PHO be on an impact course or actually impact the Earth.
In the event that experts find a PHO or predict a possible, probable, or certain impact with Earth, the PDCO is responsible for providing timely and accurate information to the Government, the media, and the public. The Minor Planet Center is tasked with notifying observers worldwide about PHOs so they can conduct timely follow-up observations. The Jet Propulsion Laboratory’s Center for NEO Studies (CNEOS) analyzes data collected on PHOs, predicts future orbits, and calculates impact probabilities. CNEOS will use new data to refine its predictions of the PHO’s orbit. If a PHO poses a significant chance of impacting Earth (that is, greater than 1 percent over the next 100 years), the PDCO prepares notification messages for the NASA Administrator to send to the Executive Office of the President, the U.S. Congress, and other Government organizations.
In conducting its work, the PDCO collaborates with other U.S. Government agencies, other national and international agencies, and professional and amateur astronomers around the world. For example, the PDCO works closely with the Federal Emergency Management Agency and the Department of State on NEO impact warning, mitigation and response planning. The PDCO is responsible for facilitating communications between the science community and the public should any potentially hazardous NEO be discovered. The PDCO also works closely with the United Nations Office of Outer Space Affairs, its Committee on the Peaceful Uses of Outer Space, and its Action Team on Near Earth Objects (also known as Action Team 14). The PDCO is a leading member of the International Asteroid Warning Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG), multinational endeavors recommended by the United Nations for an international response to the NEO impact hazard and established and operated by the space-capable nations. The PDCO also communicates with the scientific community through channels such as NASA’s Small Bodies Assessment Group (SBAG).
NASA reorganized its Near Earth Object Observations Program and established a Planetary Defense Coordination Office in January 2016 in response to the NASA Office of Inspector General’s 2014 report, “NASA’s Efforts to Identify Near-Earth Objects and Mitigate Hazards.”
Near Earth Object Observations Program
NASA’s Near-Earth Object (NEO) Observations Program is responsible for finding, tracking, and characterizing near-Earth objects – asteroids and comets whose orbits periodically bring them within approximately 1.3 Astronomical Units (AU) of the Sun. This implies that they can come within 0.3 AU – about 30 million miles, or 50 million kilometers – of Earth’s orbit. The Program is a key element of the Agency’s Planetary Defense Coordination Office.
The NEO Observations Program sponsors applied research conducted at NASA field centers, astronomical observatories, and other locations around the United States.
All NEO search and tracking projects supported by the Program are required to make their data permanently available in a timely manner to the scientific community. The internationally recognized public archive for these data is the Minor Planet Center, which is sanctioned by the International Astronomical Union and supported by the NEO Observations Program.
The Jet Propulsion Laboratory (JPL) in Pasadena, California, manages a Center for NEO Studies (CNEOS) for the Headquarters NEO Observations Program and conducts a number of Headquarters-sponsored NEO projects.
The NEO Observations Program supports NEO surveys that contribute to a sustained and productive campaign to find and track NEOs, collecting data of sufficient precision to allow accurate predictions of the future trajectories of discovered objects. The Program also supports efforts to characterize a representative sample of NEOs by measuring their sizes, shapes, and compositions. In addition, the Program devotes a limited amount of funding to research into NEO impact mitigation and deflection strategies and techniques.
This diagram maps the data gathered from 1994-2013 on small asteroids impacting Earth’s atmosphere and disintegrating to create very bright meteors, technically called “bolides” and commonly referred to as “fireballs”. Sizes of orange dots (daytime impacts) and blue dots (nighttime impacts) are proportional to the optical radiated energy of impacts measured in billions of Joules (GJ) of energy, and show the location of impacts from objects about 1 meter (3 feet) to almost 20 meters (60 feet) in size.
NASA-funded survey projects have found more than 95 percent of the known catalogue of over 15,000 NEOs. NASA-funded surveys are currently finding NEOs at a rate of about 1,500 per year. The current congressionally directed objective of the NEO Observations Program is to find, track, and catalogue at least 90 percent of the estimated population of NEOs that are equal to or greater than 140 meters in size by 2020 and to characterize a subset of those objects that is representative of the entire population. Roughly half of the known catalogue of NEOs are objects larger than 140 meters in size. The predicted population of NEOs of this size is about 25,000. Current surveys are finding NEOs of this size at a rate of about 500 per year. The Jet Propulsion Laboratory’s Center for NEO Studies maintains up-to-date statistics on NEO discoveries.
NASA has been studying NEOs since the 1970s. The Agency initiated a survey, commonly called “Spaceguard,” in the 1990s to begin to search for them. NASA participated in the International Spaceguard Survey, initiated in 1996 and sponsored by the multinational Spaceguard Foundation. NASA now participates as a key member in the International Asteroid Warning Network (IAWN), recommended by the United Nations Committee on the Peaceful Uses of Outer Space (UN-COPUOS) as the unified response for all space-capable nations to address the NEO impact hazard. To date, NASA-sponsored NEO surveys have provided 98 percent of all NEO detections.
In 1992, NASA began conducting scientific workshops and research into the identification, characterization, and tracking of NEOs, as well as into potential mitigation strategies. NASA reported that NEOs with a diameter greater than 0.62 miles (1 kilometer) posed the greatest hazard to life on Earth and predicted that an organized survey could identify most NEOs of this size within a decade.
NASA started the NEO Observations Program in 1998 in response to congressional direction. The Program has had multiple directives, including:
A 1994 request from House Committee on Science, Space, and Technology to develop a plan to discover, characterize and catalog within ten years (to the extent practicable), the potentially threatening comets and asteroids larger than 1 kilometer in diameter. A 1998 congressional directive to conduct a program to discover at least 90 percent of 1-kilometer-diameter or larger NEOs within ten years. (This directive was met in 2010.
A directive in NASA’s fiscal year 2005 authorization act to provide an analysis of alternatives to detect, track, catalogue, and characterize potentially hazardous near-Earth objects and develop a program by December 28, 2006, to survey 90 percent of the potentially hazardous objects measuring at least 140 meters in diameter by the end of 2020. In addition, this legislation directed NASA to submit an analysis of alternatives that NASA could employ to divert an object on a likely collision course with Earth. (NASA is in the process of complying with these directives.) The 2005 authorization act also amended the National Aeronautics and Space Act of 1958 to state that “the general welfare and security of the United States require that the unique competence of [NASA] be directed to detecting, tracking, cataloguing, and characterizing near-Earth asteroids and comets in order to provide warning and mitigation of the potential hazard of such near-Earth objects to the Earth.”
A directive in U.S. National Space Policy of June 28, 2010, to pursue capabilities, in cooperation with other departments, agencies, and commercial partners, to detect, track, catalog, and characterize near-Earth objects to reduce the risk of harm to humans from an unexpected impact on our planet and to identify potentially resource-rich planetary objects. (NASA is in the process of complying with this directive.)
The NEO Observations Program operated on a budget of a few million dollars per year from fiscal year 1998 through fiscal year 2010, at which point the program budget was about $4 million. In April 2010, the President announced a new goal for NASA: a human mission to an asteroid. Consequently, the President requested, and Congress authorized in 2012, $20.4 million for an expanded NASA NEO Observations Program. The Program was again expanded in fiscal year 2014, with a budget of $40 million and again in 2016 to $50 million.
The NEO Observations Program supports multiple detection and tracking campaigns using ground-based optical telescopes and the space-based NEOWISE mission; follow-up surveys; NEO characterization efforts; radar imaging of NEOs; data processing, analysis and management centers; technology development projects; and studies of techniques for impact mitigation. These projects are being conducted by NASA centers, other federal agencies, federally funded research and development centers, space science institutes, university researchers, and private citizens.
The NEO Observations Program is supporting NASA’s Asteroid Redirect Mission by providing information on the orbits and characteristics of NEOs that might be accessible for human missions.
The NEO Observations Program is also managing the Agency’s Asteroid Grand Challenge, an effort using multidisciplinary collaborations and a variety of partnerships with other government agencies, international partners, industry, academia, and citizen scientists to contribute to the NEO Observations Program’s ongoing work.
NASA’s Office of Safety and Mission Assurance maintains a Meteoroid Environment Office. Meteoroids are small remnants of asteroids and comets. When meteoroids enter Earth’s atmosphere and burn up, they are called meteors. This office, based at NASA’s Marshall Space Flight Center, monitors the meteoroid environment and provides meteor shower forecasts to NASA spacecraft operators.