Non-Planetary Science Potential of the Prospective Uranus Mission

<p><span dir="ltr" role="presentation">With the recent announcement of a flagship Uranus mission by </span><span dir="ltr" role="presentation">NASA&#8217;s <em>Planetary Science and Astrobiology Decadal Survey for </em></span><span dir="ltr" role="presentation"><em>2023-2032</em>,</span> <span dir="ltr" role="presentation">Uranus might be visited again by a spacecraft for the </span><span dir="ltr" role="presentation">first time after the</span> <em><span dir="ltr" role="presentation">Voyager II</span></em> <span dir="ltr" role="presentation">mission in the late 1980s. </span>The prospective Uranus Orbiter mission is not only significant for learning about the Uranian system, but also an exceptional opportunity for non-planetary radio science, due to long spacecraft cruise periods and travel distances.</p> <div class="page" title="Page 2"> <div class="layoutArea"> <div class="column"> <p>Proposed mission plans to Uranus involve 9 years of cruise time, during which the scientific potential of the spacecraft is not fully utilized. Radio communication between Earth and a distant spacecraft presents a unique case for investigating various phenomena via Doppler tracking, such as:</p> <ul> <li>(i) Searching for low-frequency gravitational waves from supermassive blackhole binary mergers.<strong>⁽¹⁾</strong></li> <li>(ii) Placing constraints on the local dark matter content in the solar system and testing alternative theories of gravity.<strong>⁽²⁾</strong></li> <li>(iii) L<span dir="ltr" role="presentation">ocalizing the hy</span><span dir="ltr" role="presentation">pothetical <em>Planet 9</em>.<strong>⁽³⁾</strong></span></li> </ul> <p><span dir="ltr" role="presentation">To this end, we estimate the feasibility of all these prospects for different physical models, as well as varying sensitivities of the Earth-spacecraft radio link. Our findings suggest that, </span>with a significant but realistic improvement from the Cassini-era Doppler link sensitivity, there is a good chance of realizing all of the proposed cases above.&#160;</p> <div class="page" title="Page 3"> <div class="layoutArea"> <div class="column"> <p>^{<strong>(1)</strong>}<em>Soyuer D., Zwick L., D&#8217;Orazio D., Saha P., 2021, MNRAS, 503, L73, </em>^{<strong>(2)</strong>}<em>Zwick L., Soyuer D., Bucko J., 2022, A&A, 664, A188,&#160; </em><strong>⁽³⁾</strong><em>Bucko J., Soyuer D., Zwick L., (in prep.)</em></p> </div> </div> </div> </div> </div> </div>