Planetary Decadal and Community Findings

Planetary Science Decadal Survey

The ngRADAR project is responsive to the findings and recommendations published in the planetary science decadal survey by the National Academies of Science, Engineering, and Medicine entitled "Origins, Worlds, and Life:  A Decadal Strategy for Planetary Science and Astrobiology 2023-2032."  The planetary decadal takes community input and makes recommendations to the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA) on how to address the key scientific questions in planetary science over the next decade.  NASA provided an initial response to the planetary science decadal survey in August 2022.


Page 18-12:  “As the steward of ground-based observatories with NEO [near-Earth object] observing capabilities, NSF should support and prioritize critical planetary defense observations of NEOs at its ground-based facilities.”

ngRADAR consists of a transmitter system on the NSF's Green Bank Telescope and receivers at the NSF's Very Long Baseline Array.  In the future, the NSF's Next Generation Very Large Array (ngVLA) could also function as a receiving system for ngRADAR, greatly increasing its sensitivity by greatly increasing its receiving area.  Establishing the ngRADAR planetary radar system makes use of existing infrastructure at NSF's ground-based facilities and allows a new capability to be realized without the need to construct a new facility.


Page 18-12:  “In order to conduct the required NEO follow-up characterization observations to meet key planetary defense objectives, it would be valuable to expand and extend planetary radar capabilities to obtain coverage over the northern and southern celestial hemispheres.”

ngRADAR expands planetary radar capabilities in the northern hemisphere by making use of the Green Bank Telescope and the Very Long Baseline Array of antennas spread across the United States from Hawaii to St. Croix in the Virgin Islands, which provides complementarity and redundancy to existing planetary radar assets, especially for follow-up physical and dynamical characterization of NEOs.


Page 21-20:  “Development of advanced radar technologies to improve NEO follow-up, tracking, and characterization capabilities would enhance planetary defense preparation.”

ngRADAR makes use of solid-state power amplifiers known as gallium-nitride monolithic microwave integrated circuits (GaN MMICs) that have not been used previously for planetary radar systems.  ngRADAR also pushes to higher transmit frequencies (13.7 GHz; 2.19 cm) than other planetary radar systems, is capable of finer resolution resolution (sub-meter) than other planetary radar systems by using up to 600 MHz of waveform bandwidth, and seeks to combine the signals received by multiple telescopes into a radar-receiving array.


Page 20-15/22-45:  “NASA and NSF should review the current radar infrastructure to determine how best to meet the community’s needs, including expanded capabilities at existing facilities, to replace those lost with Arecibo.”

ngRADAR, as stated above, makes use of existing NSF facilities by expanding their capabilities to include radar transmission and reception, which will help fill the void left by the loss of the planetary radar system at Arecibo Observatory.


Page 18-12:  “NASA and NSF should support studies to develop a plan for ground-based planetary radar capabilities comparable to or exceeding those of the Arecibo Observatory necessary for achieving planetary defense objectives.”

ngRADAR looks forward to supporting discussions and studies by NASA and NSF about the future of ground-based planetary radar capabilities and how ngRADAR can help achieve planetary defense objectives.


NASA Small Bodies Assessment Group Findings

For many years, planetary radar and planetary-radar facilities have featured prominently in the findings of the community-driven Small Bodies Assessment Group (SBAG), which was established by NASA in 2008.  SBAG produces findings during biannual meetings of the small-bodies community and passes them along to the Planetary Science Advisory Committee (PAC) to elicit responses from NASA.  The SBAG findings from January 2022, once again, included support for planetary radar stating:

Finding:  "SBAG commends NASA for supporting additional asteroid radar observations at other facilities in order to meet a portion of the scientific and planetary defense goals previously accomplished by the Arecibo Observatory. SBAG encourages NASA to continue planned upgrades to radar capabilities at the Goldstone and Canberra Deep Space Network sites, and recommends that NASA continue to work with NSF and other agencies to develop new planetary radar facilities. The current efforts to install a planetary radar system at the existing Green Bank Telescope are an example of how such collaborations can aid the development of additional planetary radar capabilities."

The Outer Planets Assessment group (OPAG) concurred with SBAG's finding in support of NASA and NSF working to "develop a concerted plan for new national resources for planetary radar."

ngRADAR presents a way forward for developing planetary radar capabilities using existing infrastructure of the NSF, which can be applied to goals and objectives for planetary science and planetary defense often spearheaded by NASA.


National Near-Earth Object Preparedness Strategy and Action Plan

The National Science & Technology Council established the Interagency Working Group for Detecting and Mitigating the Impact of Earth-Bound Near-Earth Objects (DAMIEN) to produce the National Near-Earth Object Preparedness Strategy and Action Plan, a document outlining how to "improve capabilities for prediction (detection, characterization, and monitoring) and National preparedness (protection, mitigation, response, and recovery)."  Among the action items supporting the strategic objective to "improve national capabilities for NEO detection, tracking, and remote characterization" assigned to NASA, the NSF, and the US Air Force was to:

Action:  "Identify opportunities in existing and planned telescope programs to improve detection and tracking by enhancing the volume and quality of current data streams, including from optical, infrared, and radar facilities."

Since the announcement of the National Near-Earth Object Preparedness Strategy and Action Plan in 2018, a federal interagency working group led by the NSF and supported by NASA, the US Air Force, and other interested parties has been stood up to review national needs and requirements for planetary radar as a national asset.  Also during this time, Arecibo Observatory was decommissioned and ultimately collapsed, leaving a void in the volume and quality of data streams from radar facilities.  ngRADAR has the potential to fill this gap in national capabilities for planetary radar, enhancing the volume of observations possible as a complement to the Goldstone Solar System Radar (science), while pushing to new wavelengths and higher resolutions to increase the quality of data streams from radar facilities in the future.


National Cislunar Science & Technology Strategy

The National Science & Technology Council established the subcommittee on Cislunar Technology Strategy Interagency Working Group to produce the National Cislunar Science & Technology Strategy, a document that "provides a first interagency strategy to guide the actions of the U.S. government in advancing scientific, exploration, and economic development activities in Cislunar space."  Among the four key objectives of the federal cislunar strategy is:

Objective:  "Extend U.S. space situational awareness capabilities into Cislunar space. Space situational awareness is the necessary foundation to enable transparency and safe operations for all entities operating in Cislunar space. As activities in Cislunar space increase, the U.S. government will define requirements for new space situational awareness capabilities, including associated reference systems and data-sharing approaches. The United States will pursue new cost-effective capabilities while improving existing capabilities as necessary. This objective has synergies with efforts to provide early warning for potentially hazardous asteroids."

ngRADAR, by its bistatic (multistatic) nature, will be able to observe without the limitation of having to switch between transmit and receive modes at the same antenna.  This opens up a capability of studying targets between Earth and the Moon, including cislunar space debris and close-approaching near-Earth objects.  While other systems can study space debris in low-Earth orbit or geosynchronous orbit about the Earth, ngRADAR will have the sensitivity to study space debris in higher orbits, all the way to the Moon itself.  This will help fill strategic knowledge gaps in the amount and type of debris in the cislunar region for space situational awareness (especially as humans return to the Moon) as well as provide tracking and characterization of potentially hazardous natural bodies.