Planetary Science Decadal Survey Research Articles

Radio Science Experiments during a Cruise Phase to Uranus

The exploration of Uranus, a key archetype for ice giant planets and a gateway to understanding distant exoplanets, is acquiring increasing interest in recent years, especially after the Uranus Orbiter and Probe (UOP) mission has been prioritized in the Planetary Science Decadal Survey 2023–2032. This paper presents the results of numerical simulations aimed at providing experimental constraints on the parameterized post-Newtonian (PPN) parameter γ, a measure of space–time curvature in general relativity (GR), during the cruise phase of a spacecraft travelling to Uranus. Leveraging advanced radio tracking systems akin to those aboard the JUICE and BepiColombo missions, we explore the potential of solar conjunction experiments (SCEs) to refine current measurements of γ by exploiting the spacecraft’s long journey in the outer Solar System. We discuss the anticipated enhancements over previous estimates, underscoring the prospect of detecting violations of GR. Our simulations predict that by using an advanced radio tracking system, it is possible to obtain an improvement in the estimation of γ up to more than an order of magnitude with respect to the latest measurement performed by the Cassini–Huygens mission in 2002, contingent on the calibration capabilities against solar plasma noise. The results reveal that a number of SCEs during the mission can substantially strengthen the validation of GR. In tandem with fundamental physics tests, the use of radio links during SCEs presents a valuable opportunity to dissect the solar corona’s plasma dynamics, contributing to solar physics and space weather forecasting. This paper also enumerates methodologies to analyze electron density, localize plasma features, and deduce solar wind velocity, enriching the scientific yield of the experiments beyond the primary objective of testing GR during the cruise phase of a mission to Uranus.

VALENTInE: A Concept for a New Frontiers–Class Long-duration In Situ Balloon-based Aerobot Mission to Venus

Described here is a concept for a variable-altitude aerobot mission to Venus developed as part of the 2020 NASA Planetary Science Summer School in collaboration with NASA Jet Propulsion Laboratory. The Venus Air and Land Expedition: a Novel Trailblazer for in situ Exploration (VALENTInE) is a long-duration New Frontiers–class mission to Venus in alignment with the goals recommended by the 2013 Planetary Science Decadal Survey. VALENTInE would have five science objectives: (1) determine the driving force of atmospheric superrotation, (2) determine the source of D/H and noble gas inventory, (3) determine the properties that govern how light is reflected within the lower cloud later, (4) determine whether the tesserae are felsic, and (5) determine whether there is evidence of a recent dynamo preserved in the rock record. The proposed mission concept has a total duration of 15 Earth days and would float at an altitude of 55 km, along with five dips to a lower altitude of 45 km to study Venus’s lower atmosphere. The instrument payload allows for measurements of the atmosphere, surface, and interior of Venus and includes six instruments: an atmospheric weather suite, a mass spectrometer, a multispectral imager, a near-infrared spectrometer, light detection and ranging, and a magnetometer. Principle challenges included a limitation caused by battery lifetime and low technology readiness levels for aerobots that can survive the harsh conditions of Venus’s atmosphere. This preliminary mission was designed to fit within an assumed New Frontiers 5 (based on inflated New Frontiers 4) cost cap.

Sediments Within the Icy North Polar Deposits of Mars Record Recent Impacts and Volcanism

AbstractThe North Polar Layered Deposits (NPLD) of Mars are ice‐rich sedimentary layers that formed under the influence of Mars' modern climate and thus record the recent climatic history of Mars, analogous to terrestrial ice sheets. The 2013–2023 Planetary Science Decadal Survey recommends a lander mission to sample the NPLD for climatic records; however, linking the geologic record to the climatic history will require quantitative dating of the NPLD. In this study we use orbital reflectance spectroscopy to show for the first time that dateable mafic lithics are present throughout the NPLD. We find significant glass as well as diverse crystalline minerals, which suggests that surface processes like impacts and volcanism were active during the late Amazonian and transported sediments from across the planet to the north pole. In situ investigation of the NPLD will thus provide critical quantitative constraints on both the recent geologic and climatic histories of Mars.

Advancing the Scientific Frontier with Increasingly Autonomous Systems

A close partnership between people and partially autonomous machines has enabled decades of space exploration. But to further expand our horizons, our systems must become more capable. Increasing the nature and degree of autonomy - allowing our systems to make and act on their own decisions as directed by mission teams - enables new science capabilities and enhances science return. The 2011 Planetary Science Decadal Survey (PSDS) and on-going pre-Decadal mission studies have identified increased autonomy as a core technology required for future missions. However, even as scientific discovery has necessitated the development of autonomous systems and past flight demonstrations have been successful, institutional barriers have limited its maturation and infusion on existing planetary missions. Consequently, the authors and endorsers of this paper recommend that new programmatic pathways be developed to infuse autonomy, infrastructure for support autonomous systems be invested in, new practices be adopted, and the cost-saving value of autonomy for operations be studied.

NASA Research and Analysis: Status, Issues, and Recommendations for the Planetary Science and Astrobiology Decadal Survey Committee

NASA Research and Analysis: Status, Issues, and Recommendations for the Planetary Science and Astrobiology Decadal Survey Committee

Terrestrial Planets Comparative Climatology (TPCC) mission concept

The authors and co-signers of the Terrestrial Planets Comparative Climatology (TPCC) mission concept white paper advocate that planetary science in the next decade would greatly benefit from comparatively studying the fundamental behavior of the atmospheres of Venus and Mars, contemporaneously and with the same instrumentation, to capture atmospheric response to the same solar forcing, and with a minimum of instrument-related variability. Thus, this white paper was created for the 2023-2032 Planetary Science Decadal Survey process. It describes the science rationale for such a mission, and a mission concept that could achieve such a mission.

Quantum Limited SIS Receiver Technology for the Detection of Water Isotopologue Emission From Comets

NASA's Planetary Science Decadal Survey has concluded that isotopic measurements of cometary water vapor are a means to unraveling the mysteries involving the origin of Earth's water and the evolution of our solar system. To support this, a recent Jet Propulsion Laboratory internal research program has developed quantum limited superconductor–insulator–superconductor (SIS) receivers in the important 500 $-$ 600 GHz submillimeter frequency band. These instruments can be used to detect the deuterated water (HDO) ground state (1 $_{10}$ –1 $_{01}$ ), H $_2^{16}$ O ortho ground state (1 $_{10}$ –1 $_{01}$ ), and the oxygen isotopologues H $_2^{17}$ O and H $_2^{18}$ O with exquisite sensitivity. To achieve the presented results, we have investigated aluminum oxide (AlO $_x$ ) and aluminum nitride (AlN $_x$ ) barrier SIS tunnel junction mixers on the 6- $\mu$ m silicon-on-insulator substrate. The AlO $_x$ and AlN $_x$ junction mixer blocks utilize diagonal and smooth-profile conical horns, respectively. In both cases, a commercial 4–8-GHz intermediate frequency low-noise amplifier (LNA) has been integrated into the mixer block. The AlO $_x$ (low-current-density) barrier SIS junctions were fabricated with 2- $\mu$ m gold beam-lead technology, whereas in the case of the AlN $_x$ SIS tunnel junction, we use capacitive RF decoupling tabs. The latter approach simplifies fabrication, increases yield, eases the mounting process, and facilitates scaling to higher frequencies. For an actual flight mission, with operation $\leq$ 4.2 K, the allowed heat dissipation of the mixer-integrated LNA needs to be minimized. In this article, we also investigate the receiver sensitivity as a function of the LNA dc power consumption. We find that the dc power consumption of the LNA can be reduced to $\sim$ 1.6 mW with minimal loss in sensitivity. It is anticipated that the continued InP HEMT development for quantum computer applications are likely to reduce the required LNA power dissipation even further.

QUEST: A New Frontiers Uranus orbiter mission concept study

The ice giant planets, Uranus and Neptune, are fundamentally different from the gas giant and terrestrial planets. Though ice giants represent the most common size of exoplanet and possess characteristics that challenge our understanding of the way our solar system formed and evolved, they remain the only class of planetary object without a dedicated spacecraft mission. The inclusion of a Uranus orbiter as the third highest priority Flagship mission in the NASA Planetary Science Decadal Survey “Vision and Voyages for Planetary Science in the Decade 2013–2022” indicates a high level of support for exploration of the ice giants by the planetary science community. However, given the substantial costs associated with a flagship mission, it is critical to explore lower cost options if we intend to visit Uranus within an ideal launch window of 2029–2034 when a Jupiter gravity assist becomes available. In this paper, we describe the Quest to Uranus to Explore Solar System Theories (QUEST), a New Frontiers class Uranus orbiter mission concept study performed at the 30th Annual NASA/JPL Planetary Science Summer Seminar. The proposed QUEST platform is a spin-stabilized spacecraft designed to undergo highly elliptical, polar orbits around Uranus during a notional one-year primary science mission. The proposed major science goals of the mission are (1) to use Uranus as a natural laboratory to better understand the dynamos that drive magnetospheres in the solar system and beyond and (2) to identify the energy transport mechanisms in Uranus' magnetic, atmospheric, and interior environments in contrast with the other giant planets. With substantial mass, power, and cost margins, this mission concept demonstrates a compelling, feasible option for a New Frontiers Uranus orbiter mission.

Uranus and Neptune missions: A study in advance of the next Planetary Science Decadal Survey

The ice giant planets, Uranus and Neptune, represent an important and relatively unexplored class of planet. Most of our detailed information about them comes from fleeting looks by the Voyager 2 spacecraft in the 1980s. Voyager, and ground-based work since then, found that these planets, their satellites, rings, and magnetospheres, challenge our understanding of the formation and evolution of planetary systems. We also now know that Uranus-Neptune size planets are common around other stars. These are some of the reasons ice giant exploration was a high priority in NASA's most recent Planetary Science Decadal Survey. In preparation for the next Decadal Survey, NASA, with ESA participation, conducted a broad study of possible ice giant missions in the 2024–2037 timeframe. This paper summarizes the key results of the study, and addresses questions that have been raised by the science community and in a recent NASA review. Foremost amongst these are questions about the science objectives, the science payload, and the importance of an atmospheric probe. The conclusions of the NASA/ESA study remain valid. In particular, it is a high priority to send an orbiter and atmospheric probe to at least one of the ice giants, with instrumentation to study all components of an ice giant system. Uranus and Neptune are found to be equally compelling as science targets. The two planets are not equivalent, however, and each system has things to teach us the other cannot. An additional mission study is needed to refine plans for future exploration of these worlds.

Mr. Bridenstine's “To Do” List

Mr. Bridenstine's “To Do” List

OCEANUS: A high science return Uranus orbiter with a low-cost instrument suite

Ice-giant-sized planets are the most common type of observed exoplanet, yet the two ice giants in our own solar system (Uranus and Neptune) are the least explored class of planet, having only been observed through ground-based observations and a single flyby each by Voyager 2 approximately 30 years ago. These single flybys were unable to characterize the spatial and temporal variability in ice giant magnetospheres, some of the most odd and intriguing magnetospheres in the solar system. They also offered only limited constraints on the internal structure of ice giants; understanding the internal structure of a planet is important for understanding its formation and evolution. The most recent planetary science Decadal Survey by the U.S. National Academy of Sciences, “Vision and Voyages for Planetary Science in the Decade 2013–2022,” identified the ice giant Uranus as the third highest priority for a Flagship mission in the decade 2013–2022. However, in the event that NASA or another space agency is unable to fly a Flagship-class mission to an ice giant in the next decade, this paper presents a mission concept for a focused, lower cost Uranus orbiter called OCEANUS (Origins and Composition of the Exoplanet Analog Uranus System). OCEANUS would increase our understanding of the interior structure of Uranus, its magnetosphere, and how its magnetic field is generated. These goals could be achieved with just a magnetometer and the spacecraft's radio system. This study shows that several of the objectives outlined by the Decadal Survey, including one of the two identified as highest priority, are within reach for a New-Frontiers-class mission.

IMARS Phase 2A Draft Mission Architecture and Science Management Plan for the Return of Samples from Mars Phase 2 Report of the International Mars Architecture for the Return of Samples (iMARS) Working Group.

iMARS Phase 2A Draft Mission Architecture and Science Management Plan for the Return of Samples from Mars Phase 2 Report of the International Mars Architecture for the Return of Samples (iMARS) Working Group.

Conference Summary: Life Detection in Extraterrestrial Samples

In February 2012, a conference was convened at the Scripps Institution of Oceanography in La Jolla, California, on the subject of life detection in extraterrestrial samples (program and abstracts available at http://www.lpi.usra.edu/meetings/ lifedetection2012). The aim of the conference was to explore the kinds of tools, methods, and approaches necessary for detecting evidence of life in extraterrestrial samples, including those that arrive on Earth by natural processes and those that are deliberately returned by engineered missions. Samples that might be returned from Mars by a future mission were a primary topic of interest. Presentations and discussions at the conference drew upon diverse fields of research, including meteorite studies, modern and ancient terrestrial analog studies, studies of samples returned by past lunar and comet sample return missions, studies of modern traces of life on Earth, and studies of the facilities needed to conduct this kind of research. The conference program was organized with extensive discussion sessions. This report summarizes the results of the conference. The topic of life detection was examined from two different but partially overlapping perspectives: the ‘‘science perspective’’ arising from the desire to know whether life ever arose on Mars and the ‘‘planetary protection perspective’’ arising from the need to protect our own planet from contamination by any potentially harmful living extraterrestrial organisms that may be contained in returned samples. The former relates to detection of any kind of evidence of either ancient or present-day life, whereas the latter is concerned with evidence of present-day viable organisms. A review of the topic of life detection is timely given the scope of recent advances in life-detection studies on Earth, the publication of the National Research Council’s Planetary Science Decadal Survey (which identified seeking the signs of life via Mars sample return (MSR) as its highest priority in the flagship class of missions; National Research Council, 2011), as well as the strategic emphasis within both NASA and ESA on life detection. One of the primary approaches to life detection is via the study of extraterrestrial samples, although other astrobiological approaches also exist. In the case of a potential MSR campaign, significant forward planning is required to ensure best possible practices are implemented throughout the campaign (iMARS Working Group, 2008; MEPAG E2E-iSAG, 2012): from the design and operation of a sample collection rover to containment and preservation of samples in transit, and appropriate handling and analysis of the samples after they have returned to Earth. The array of planned or possible life-detection strategies and measurements has implications for virtually every aspect of a sample return campaign. Thus, it is critical to understand these strategies and measurements well in advance to avoid compromising the fundamental scientific objectives and planetary protection requirements of an MSR campaign. Much of the discussion summarized below assumed MSR would be a robotic endeavor. However, the mission may ultimately involve humans rather than robots. In that case, some aspects of laboratory analyses and sample handling may need to be reassessed. The conference was also an introduction to a subsequent planetary protection workshop dealing specifically with the planetary protection test protocol.

Mission to the Trojan asteroids: Lessons learned during a JPL Planetary Science Summer School mission design exercise

The 2013 Planetary Science Decadal Survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar System. We present a conceptual design for a mission to the Jovian Trojan asteroids: the Trojan ASteroid Tour, Exploration, and Rendezvous (TASTER) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary Science Summer School. Our proposed mission includes visits to two Trojans in the L4 population: a 500km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000–100 km over a 12 month nominal science data capture period. Our proposed instrument payload – wide- and narrow-angle cameras, a visual and infrared mapping spectrometer, and a neutron/gamma ray spectrometer – would provide unprecedented high-resolution, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar System. Although our mission design was completed as part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large differences in the complex trade-offs required when designing a mission to the Trojan asteroids.

A lunar L2-Farside exploration and science mission concept with the Orion Multi-Purpose Crew Vehicle and a teleoperated lander/rover

A novel concept is presented in this paper for a human mission to the lunar L2 (Lagrange) point that would be a proving ground for future exploration missions to deep space while also overseeing scientifically important investigations. In an L2 halo orbit above the lunar farside, the astronauts aboard the Orion Crew Vehicle would travel 15% farther from Earth than did the Apollo astronauts and spend almost three times longer in deep space. Such a mission would serve as a first step beyond low Earth orbit and prove out operational spaceflight capabilities such as life support, communication, high speed re-entry, and radiation protection prior to more difficult human exploration missions. On this proposed mission, the crew would teleoperate landers/rovers on the unexplored lunar farside, which would obtain samples from the geologically interesting farside and deploy a low radio frequency telescope. Sampling the South Pole-Aitken basin, one of the oldest impact basins in the solar system, is a key science objective of the 2011 Planetary Science Decadal Survey. Observations at low radio frequencies to track the effects of the Universe’s first stars/galaxies on the intergalactic medium are a priority of the 2010 Astronomy and Astrophysics Decadal Survey. Such telerobotic oversight would also demonstrate capability for human and robotic cooperation on future, more complex deep space missions such as exploring Mars.

US planetary sciences to focus on smaller missions, research, and technology development

Heeding community advice, NASA’s planetary science division seeks to scale back its flagship missions while retaining strong international partnerships.

Priority Planetary Science Missions Identified

The U.S. National Research Council's (NRC) planetary science decadal survey report, released on 7 March, lays out a grand vision for priority planetary science missions for 2013–2022 within a tightly constrained fiscal environment. The cost‐conscious report, issued by NRC's Committee on the Planetary Science Decadal Survey, identifies high‐priority flagship missions, recommends a number of potential midsized missions, and indicates support for some smaller missions. The report states that the highest‐priority flagship mission for the decade is the Mars Astrobiology Explorer‐Cacher (MAX‐C)—the first of three components of a NASA/European Space Agency Mars sample return campaign—provided that the mission scope can be reduced so that MAX‐C costs no more than $2.5 billion. The currently estimated mission cost of $3.5 billion “would take up a disproportionate near‐term share of the overall budget for NASA's Planetary Science Division,” the report notes.

Viewing NASA's Mars Budget with Resignation

I would like to clarify several points in the News of the Week story (26 September, p. [1754][1]) by A. Lawler, “Rising costs could delay NASA's next mission to Mars and future launches.” When the National Research Council's Planetary Science Decadal Survey recommended the Mars Science Laboratory (MSL) mission for priority funding, it assigned a cost level of $650 million. This value, rather than $1.4 billion, is the true metric for seeing the deep damage that MSL's profligately overrunning cost—now likely to top $2.1 billion—has inflicted on NASA's Mars and wider planetary science budget. Also, the story focused its overrun discussion on instrument costs. Although certainly part of the problem, instrument cost increases have been considerably smaller than overruns in the rest of MSL's budget, which was severely mismatched to the project's complexity from its inception. This mismatch sowed the most fundamental seeds of MSL's cost problems. The article's end quote described NASA's Mars Sample Return (MSR) mission plan as “smoke and mirrors.” Disappointingly, MSR is becoming a mirage in the wake of MSL and other budget damage caused by numerous substantial Science Mission Directorate (SMD) cost overruns accepted in recent months. However, as evidenced by both internal NASA and external Office of Management and Budget scrutiny in 2007, NASA's MSR plan in the President's Fiscal Year 2009 budget did fit in SMD's future budget envelope. It could well have launched near 2020, had a strong emphasis on cost control been sustained as a priority. Finally, there was no mention that a NASA independent review team found numerous development issues that called MSL's 2009 launch date into serious doubt almost a year ago. Nor did it describe that scenarios for dealing with MSL without causing such deep budgetary damage elsewhere were proposed by SMD but rejected at higher levels in early 2008. That, and the concurrent, forced disbanding of the MSL independent review team, precipitated my resignation as SMD Associate Administrator. [1]: /lookup/doi/10.1126/science.321.5897.1754