NASA Planetary Science Research Articles

Astrobiology eXploration at Enceladus (AXE): A New Frontiers Mission Concept Study

The Saturnian moon Enceladus presents a unique opportunity to sample the contents of a subsurface liquid water ocean in situ via the continuous plume formed over its south polar terrain using a multi-flyby mission architecture. Previous analyses of the plume’s composition by Cassini revealed an energy-rich system laden with salts and organic compounds, representing an environment containing most of the ingredients for life as we know it. Following in the footsteps of the Cassini-Huygens mission, we present Astrobiology eXploration at Enceladus (AXE), a New Frontiers class Enceladus mission concept study carried out during the 2021 NASA Planetary Science Summer School program at the Jet Propulsion Laboratory, California Institute of Technology. We demonstrate that a scientifically compelling geophysical and life-detection mission to Enceladus can be carried out within the constraints of a New Frontiers-5 cost cap using a modest instrument suite, requiring only a narrow angle, high-resolution telescopic imager, a mass spectrometer, and a high-gain antenna for radio communications and gravity science measurements. Using a multi-flyby mission architecture, AXE would evaluate the habitability and potential for life at Enceladus through a synergistic combination of in situ chemical analysis measurements aimed at directly detecting the presence of molecular biosignatures, along with geophysical and geomorphological investigations to contextualize chemical biosignatures and further evaluate the habitability of Enceladus over geologic time.

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.

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.

Scientists Identify Exploration Goals for Venus

Since the turn of the millennium, a large proportion of NASA's planetary science missions—including spacecraft and payloads on four orbiting missions and three rovers—has targeted Mars in preparation for future human missions to the red planet. Less studied, however, is Venus.

Time-resolved neutron/gamma-ray data acquisition for in situ subsurface planetary geochemistry

The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface elemental composition of planetary bodies in situ. Previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on neutrons produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated.

PHYSICAL PARAMETERS OF ASTEROIDS ESTIMATED FROM THE WISE 3-BAND DATA AND NEOWISE POST-CRYOGENIC SURVEY

Enhancements to the science data processing pipeline of NASA's Wide-field Infrared Explorer (WISE) mission, collectively known as NEOWISE, resulted in the detection of $>$158,000 minor planets in four infrared wavelengths during the fully cryogenic portion of the mission. Following the depletion of its cryogen, NASA's Planetary Science Directorate funded a four month extension to complete the survey of the inner edge of the Main Asteroid Belt and to detect and discover near-Earth objects (NEOs). This extended survey phase, known as the NEOWISE Post-Cryogenic Survey, resulted in the detection of $\sim$6500 large Main Belt asteroids and 88 NEOs in its 3.4 and 4.6 $\mu$m channels. During the Post-Cryogenic Survey, NEOWISE discovered and detected a number of asteroids co-orbital with the Earth and Mars, including the first known Earth Trojan. We present preliminary thermal fits for these and other NEOs detected during the 3-Band Cryogenic and Post-Cryogenic Surveys.

Scientists Decry Cuts That Would Doom ExoMars Missions

The president's 2013 budget request eliminates funding for the 2016 Mars mission called Trace Gas Orbiter, which received $27 million this year, as part of a 20% cut to NASA's planetary science division.

White House Budget Proposal Favorable Overall for Federal Science Agencies

President Barack Obama's proposed federal budget of $3.8 trillion for fiscal year (FY) 2013, released on 13 February, provides an overall favorable funding picture for federal science agencies in a tight economic environment. However, there are also a number of proposed decreases, including a sharp cut to NASA's Planetary Science account. Overall, the budget proposal includes $140.8 billion for the federal investment in research and development, a 1.4% increase above the FY 2012 enacted level. Funding for federal basic and applied research would be $64 billion, 3.3% above FY 2012 enacted levels. Funding for defense research and development (R&D) would decrease to $75.9 billion, a drop of 1.5%; nondefense R&D would increase 5% to $64.9 billion.

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.

PRELIMINARY RESULTS FROM NEOWISE: AN ENHANCEMENT TO THEWIDE-FIELD INFRARED SURVEY EXPLORERFOR SOLAR SYSTEM SCIENCE

The Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at four infrared wavelengths with greatly improved sensitivity and spatial resolution compared to its predecessors, the Infrared Astronomical Satellite and the Cosmic Background Explorer. NASA's Planetary Science Division has funded an enhancement to the WISE data processing system called "NEOWISE" that allows detection and archiving of moving objects found in the WISE data. NEOWISE has mined the WISE images for a wide array of small bodies in our solar system, including near-Earth objects (NEOs), Main Belt asteroids, comets, Trojans, and Centaurs. By the end of survey operations in 2011 February, NEOWISE identified over 157,000 asteroids, including more than 500 NEOs and ∼120 comets. The NEOWISE data set will enable a panoply of new scientific investigations.

Women and mission leadership

Only one of NASA's planetary science flight missions in the past 30 years has been led by a women scientist as Principal Investigator. The number of senior women in the field is small, but women are still underutilized, as seen by a cohort age analysis correlating with median ages for various key science roles. Worse, the more junior women are not joining missions as Co-Investigators and Participating Scientists at rates approaching their representation in the field of planetary science. In fact, they are underutilized in these roles not by a few percent, but by greater than a factor of two. The pipeline of women gaining mission experience today is increasing, but it is not keeping pace with the rate that women are now choosing to stay in the field for postdoctoral studies and beyond. The numbers definitively show for the first time that, for whatever reason, women are still underrepresented in mission leadership at NASA.

Neutron sources for in-situ planetary science applications

There are a number of future European Space Agency (ESA) and NASA planetary science missions that are in the planning or initial study phases, where the scientific objectives include determining the surface composition, measuring planetary surface heat flow and constraining planetary chronology. The University of Leicester is developing instrumentation for geophysical applications that include γ-ray spectroscopy, γ-ray densitometry and radiometric dating. This paper describes the modelling of a geophysical package, with the Monte Carlo code MCNPX, in order to determine the impact that a neutron source would have on in-situ composition measurements, radiometric dating and, in particular, trace element detection. The suitability of ∅ 2.54×2.54 cm LaBr 3(Ce) detectors in the geophysical package for in-situ missions was examined. 252Cf, Am–Be and Pu–Be neutron sources were compared in a trade-off study to determine mission suitability, potential for thermal and electric power production, mass and shielding requirements. This study is linked to a parallel examination of the suitability of radioisotope thermal generators for in-situ planetary science applications. The aim of the modelling was to optimise the source type and detector geometry in order to measure the elemental peaks of interest with a precision of 10% or better based on the Poisson statistics of the detected counts above background.

Refocusing NASA planetary science funding

NASA should invest more money in data analysis for its planetary science missions, even if it means delaying or canceling a future mission, members of the science committee of the NASA Advisory Council (NAC) uggested at a 12 October meeting.Science committee member Mark Robinson, director of the Center for Planetary Sciences at Northwestern University in Chicago, Ill., said that large amounts of data from NASA planetary science missions are accumulating, and the funds for data analysis often are inadequate to properly analyze all of it. For example, there is a large amount of currently unanalyzed Mars data that could be used in planning for the Mars Science Laboratory (expected to launch in 2009), and particularly for site selection. This includes data from the recently arrived Mars Reconnaissance Orbiter, which is likely to send more data to Earth in its first year than has been collected by all previous Mars missions combined.

NASA planetary science summer school applications

NASA is accepting applications from science and engineering post‐doctoral and graduate students for its 18th Annual Planetary Science Summer School, which will hold two sessions this summer (24–28 July and 31 July 31–4 August) at the Jet Propulsion Laboratory in Pasadena, Calif.During the summer school, student teams will carry out the equivalent of an early concept study in response to a selected NASA Announcement of Opportunity prepare a proposal authorization review presentation, present it to a review board, and receive feedback.

NASA planetary science research discoveries

NASA planetary science research discoveries

NASA planetary science research discoveries

NASA planetary science research discoveries

NASA planetary science research discoveries

NASA planetary science research discoveries