A5050645585- Astro and Planetary Science
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Ionosphere and magnetosphere dynamics
- Space Exploration and Technology
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Space Satellite Systems and Control
- Space Science and Extraterrestrial Life
- GNSS positioning and interference
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Inertial Sensor and Navigation
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Space exploration and regulation
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Spacecraft Dynamics and Control
- Magnetic confinement fusion research
- Adaptive Control of Nonlinear Systems
- Spacecraft Design and Technology
- Advanced Frequency and Time Standards
- Methane Hydrates and Related Phenomena
- Advanced Research in Science and Engineering
Jet Propulsion Laboratory
2016-2025
Radar (United States)
2019
California Institute of Technology
2017
Abstract The Juno spacecraft reached the mid‐point of its nominal mission in December 2018, after completing 17 perijove passes. Ten these were dedicated to determination gravity field planet, with aim constraining interior structure. We provide an update on Jupiter's field, tidal response and spin axis motion over time. analysis Doppler data collected during passes hints a non‐static and/or non‐axially symmetric possibly related several different physical mechanisms, such as normal modes or...
Abstract The primary objective of the Europa Clipper mission is to assess habitability Europa, an overarching goal that rests on improving our understanding Europa’s interior structure, composition, and geologic activity. Here we describe Gravity Radio Science (G/RS) investigation. measurement, gravitational tidal Love number $k_{2}$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>k</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math> , will be independent...
Abstract The combination of the Doppler data from first two Juno science orbits provides an improved estimate gravity field Jupiter, crucial for interior modeling giant planets. low‐degree spherical harmonic coefficients, especially J 4 and 6 , are determined with accuracies better than previously published by a factor 5 or more. In addition, independent estimates Jovian field, obtained separately, agree within uncertainties, pointing to good stability solution. degree 2 sectoral tesseral C...
Abstract The Juno spacecraft has been orbiting Jupiter since 2016 July to deepen our comprehension of the solar system by studying gas giant. radio science experiment enables determination Jupiter’s gravitational field, thus shedding light on its interior structure. relies determining orbit during pericenter passages. Previous gravity data analyses assumed correctness general theory relativity, which was used for trajectory integration and signal propagation modeling. In this work, we aim...
Jupiter’s Great Red Spot (GRS) is the largest atmospheric vortex in Solar System and has been observed for at least two centuries. It unclear how deep extends beneath its visible cloud tops. We examined gravity signature of GRS using data from 12 encounters Juno spacecraft with planet, including direct overflights vortex. Localized density anomalies due to presence caused a shift line-of-sight velocity. Using different approaches infer depth, which yielded consistent results, we conclude...
Abstract In June 2021, the Juno spacecraft executed a close flyby of Ganymede. During encounter, passed behind Ganymede for 15 min as observed from Earth, providing geometry to conduct radio occultation experiment probe Ganymede's tenuous ionosphere. X‐band and Ka‐band links were transmitted antennas at Deep Space Network. Electrons encountered along propagation path advance signal's phase linear combination two frequencies allows direct measurement electron content path. On ingress, an...
The Juno spacecraft has been collecting data to shed light on the planet's origin and characterize its interior structure. onboard gravity science experiment based X-band Ka-band dual-frequency Doppler tracking precisely measured Jupiter's zonal gravitational field. Here, we analyze 22 Juno's passes investigate Our analysis provides evidence of new field features, which perturb otherwise axially symmetric structure with a time-variable component. We show that normal modes planet could...
Abstract Juno performed close flybys of the innermost Galilean moon, Io, in December 2023 (I57) and February 2024 (I58). During these flybys, radio link connecting spacecraft to Earth observing stations NASA's Deep Space Network (DSN) propagated through Alfvén wing, a magnetospheric feature which plasma is produced between Io Jupiter. The sensitive elevated electron densities wing. A direct measurement total content was made by linear combination Juno's X‐band Ka‐band downlink frequencies....
Abstract During its Grand Finale, the Cassini spacecraft collected crucial gravity data, revealing Saturn's low‐degree harmonics and large‐scale zonal winds extending about 8,000 km deep. However, determining high‐degree field, essential for understanding small‐scale atmospheric dynamics, is challenging due to limited spatial coverage of Cassini's periapses. To overcome this limitation, we employed Slepian functions, orthogonal within a bounded domain, represent localized field. Focusing on...
NASA&#8217;s Europa Clipper flagship mission launched on October 14, 2024 and will arrive at Jupiter in April 2030. There, it investigate the habitability of Jupiter&#8217;s moon Europa. Gravity Radio Science (G/RS) is one ten complementary investigations devoted to understanding through studies its ice shell ocean, composition, geology. G/RS makes use telecommunications system obtain radiometric tracking data during flybys.Unlike past missions, primary raw for investigation are...
The shape of Jupiter is determined primarily by the planet&#8217;s rotation rate. Additionally, its interior density distribution plays an important role in defining detailed shape. These characteristics can be used to calculate gravitational potential. Then, estimated&#160;using some estimate either polar or equatorial radius a specific pressure level, such as 1 bar 100 mb level. also affected zonal winds, creating positive anomaly order 10 km at low latitudes. However,...
The Signal of Opportunity using NASA&#8217;s Gravity Recovery and Interior Laboratory (GRAIL) radio signals to remotely sense the Lunar ionosphere has been successfully demonstrated. GRAIL mission consisted an identical pair spacecraft approximately 100 km apart in a circular polar orbit around Moon; during science period, GRAIL&#8217;s X-band Radio Science beacon (RSB) data provide applicability for occultation lunar electron density profiles with uncertainty frequency residual...
During Juno&#8217;s extended mission, the spacecraft performed four close flybys of Galilean satellites. Each encounter with a satellite occurred during ascending node crossing orbit and reduced orbital period spacecraft, phasing for subsequent encounter. each encounter, radio occultation experiment could be using science instrumentation. Ganymede in June 2021 Europa September 2022, occultations moon&#8217;s ionospheres were performed. Both yielded detections ionospheres, revealing...
The Juno extended mission (2023&#8211;2025) offers a unique opportunity to study Jupiter&#8217;s atmosphere by radio occultations. In these experiments, the atmospheric refractivity and bending angle affecting signal crossing planetary can be inferred analyzing Doppler shift induced on downlink frequencies, at X Ka bands, recorded NASA Deep Space Network stations. analysis is conducted using ray-tracing-based inversion algorithm that accounts for oblateness effects of zonal winds....
Abstract The Juno Extended Mission presented the first opportunity to acquire gravity measurements of Ganymede since end Galileo mission. These new data offered chance carry out a joint analysis with set, improving our knowledge Ganymede's field and shedding light upon its interior structure. Through reconstruction 's orbit during flybys, moon was estimated. results indicate that degree‐2 is compatible body in hydrostatic equilibrium within 1− 𝜎 hint at regional anomalies amplitudes...
Abstract Juno flew over the northern mid‐latitudes of Ganymede during orbit 34 mission, reaching an altitude 1,053 km (16:56:07.972 UTC) at a sub spacecraft latitude/longitude 33.66N, 57.5W degrees on 7 June 2021. Between 16:43 and 17:02 UT, pierced Ganymede's magnetosphere velocity relative to 18.57 s −1 . Juno's instrumentation provided unique opportunity sample local environment its magnetosphere. We present measurements composition polar ionospheric outflow energetic electrons that...
Abstract The moon Io is the dominant plasma source for Jupiter magnetosphere. distributed into a torus of material around Jupiter, called torus. Juno spacecraft performed its first perijove on 27 August 2016. During this time spacecraft's X and Ka‐band radio signals passed through From differential Doppler shift frequencies we are able to determine total electron content. content, that densities larger than predicted from Voyager ‐based models by 35 ± 14% in cold 38 beyond 5.5 R J . ion...