# Linking the Solar System and Extrasolar Planetary Systems with Radar Astronomy: Infrastructure for "Ground Truth" Comparison

## TL;DR

This paper discusses the importance of planetary radar infrastructure in studying solar system bodies and how it serves as a foundation for comparing with extrasolar planetary systems, emphasizing the need for sustained technical development.

## Contribution

It summarizes the current state of planetary radar infrastructure and proposes technical developments to enhance comparative studies of solar and extrasolar planets.

## Key findings

- Existing radar infrastructure enables unique solar system measurements.
- Ground truth data from solar system bodies supports extrasolar planet studies.
- Sustained funding and modest investments can improve system reliability.

## Abstract

Planetary radars have obtained unique science measurements about solar system bodies and they have provided orbit determinations allowing spacecraft to be navigated throughout the solar system. Notable results have been on Venus, Earth's "twin," and small bodies, which are the constituents of the Sun's debris disk. Together, these results have served as "ground truth" from the solar system for studies of extrasolar planets. The Nation's planetary radar infrastructure, indeed the world's planetary radar infrastructure, is based on astronomical and deep space telecommunications infrastructure, namely the radar transmitters at the Arecibo Observatory and the Goldstone Solar System Radar, part of NASA's Deep Space Network, along with the Green Bank Telescope as a receiving element. This white paper summarizes the state of this infrastructure and potential technical developments that should be sustained in order to enable continued studies of solar system bodies for comparison and contrast with extrasolar planetary systems. Because the planetary radar observations leverage existing infrastructure largely developed for other purposes, only operations and maintenance funding is required, though modest investments could yield more reliable systems; in the case of the Green Bank Telescope, additional funding for operations is required.