Mission Proposal Research Articles

About feasibility of SpaceX's human exploration Mars mission scenario with Starship

After decades where human spaceflight missions have been reserved to low Earth orbit, recent years have seen mission proposals and even implemented plans, e.g. with the mission Artemis I, for returning to the lunar surface. SpaceX has published over various media (e.g., its official website, conference presentations, user manual) conceptual information for its reusable Starship to enable human exploration missions to the Martian surface by the end of the decade. The technological and human challenges associated with these plans are daunting. Such a mission at that distance would require excellent system reliability and in-situ-resource utilization on a grand scale, e.g. to produce propellant. The plans contain little details however and have not yet been reviewed concerning their feasibility. In this paper we show significant technological gaps in these plans. Based on estimates and extrapolated data, a mass model as needed to fulfill SpaceX’s plans could not be reproduced and the subsequent trajectory optimization showed that the current plans do not yield a return flight opportunity, due to a too large system mass. Furthermore, significant gaps exist in relevant technologies, e.g. power supply for the Martian surface. It is unlikely that these gaps can be closed until the end of the decade. We recommend several remedies, e.g. stronger international participation to distribute technology development and thus improve feasibility. Overall, with the limited information published by SpaceX about its system and mission scenario and extrapolation from us to fill information gaps, we were not able to find a feasible Mars mission scenario using Starship, even when assuming optimal conditions such as 100% recovery rate of crew consumables during flight.

The GeoCarb greenhouse gas retrieval algorithm: simulations and sensitivity to sources of uncertainty

Abstract. The Geostationary Carbon Cycle Observatory (GeoCarb) was selected as NASA's second Earth Venture Mission (EVM-2). The scientific objectives of GeoCarb were to advance our knowledge of the carbon cycle, in particular, land–atmosphere fluxes of the greenhouse gases carbon dioxide (CO2) and methane (CH4) and the effects of these fluxes on the Earth's radiation budget. GeoCarb would retrieve column-integrated dry-air mole fractions of CO2 (XCO2), CH4 (XCH4) and CO (XCO), important for understanding tropospheric chemistry), in addition to solar-induced fluorescence (SIF), from hyperspectral resolution measurements in the O2 A-band at 0.76 µm, the weak CO2 band at 1.6 µm, the strong CO2 band at 2.06 µm, and a CH4/CO band at 2.32 µm. Unlike its predecessors (OCO-2/3, GOSAT-1/2, TROPOMI), GeoCarb would be in a geostationary orbit with a sub-satellite point centered over the Americas. This orbital configuration combined with its high-spatial-resolution imaging capabilities would provide an unprecedented view of these quantities on spatial and temporal scales accurate enough to resolve sources and sinks to improve land–atmosphere CO2 and CH4 flux calculations and reduce the uncertainty of these fluxes. This paper will present a description of the GeoCarb instrument and the L2 retrieval algorithms which will be followed by simulation experiments to determine an error budget for each target gas. Several sources of uncertainty will be explored, including that from the instrument calibration parameters for radiometric gain, the instrument line shape (ILS), the polarization, and the geolocation pointing, in addition to forward model parameters including meteorology and spectroscopy, although there are some other instrument-related sources of uncertainty that are left out for this study, including that from “smile”, the keystone effect, stray light, detector persistence, and scene inhomogeneity. The results indicate that the errors (1σ) are less than the instrument's multi-sounding precision requirements of 1.2 ppm, 10 ppb, and 12 ppb (10 %), for XCO2, XCH4, and XCO, respectively. In particular, when considering the sources of uncertainty separately and in combination (all sources included), we find overall RMSEs of 1.06 ppm for XCO2, 8.2 ppb for XCH4, and 2.5 ppb for XCO, respectively. Additionally, we find that, as expected, errors in XCO2 and XCH4 are dominated by forward model and other systematic errors, while errors in XCO are dominated by measurement noise. It is important to note that the GeoCarb mission was canceled by NASA; however, the instrument is still in development and will be delivered to NASA, in full, with the hope that it will eventually be adopted in a future mission proposal.

Daedalus Ionospheric Profile Continuation (DIPCont): Monte Carlo studies assessing the quality of in situ measurement extrapolation

Abstract. In situ satellite exploration of the lower thermosphere–ionosphere system (LTI) as anticipated in the recent Daedalus mission proposal to ESA will be essential to advance the understanding of the interface between the Earth's atmosphere and its space environment. To address physical processes also below perigee, in situ measurements are to be extrapolated using models of the LTI. Motivated by the need for assessing how cost-critical mission elements such as perigee and apogee distances as well as the number of spacecraft affect the accuracy of scientific inference in the LTI, the Daedalus Ionospheric Profile Continuation (DIPCont) project is concerned with the attainable quality of in situ measurement extrapolation for different mission parameters and configurations. This report introduces the methodological framework of the DIPCont approach. Once an LTI model is chosen, ensembles of model parameters are created by means of Monte Carlo simulations using synthetic measurements based on model predictions and relative uncertainties as specified in the Daedalus Report for Assessment. The parameter ensembles give rise to ensembles of model altitude profiles for LTI variables of interest. Extrapolation quality is quantified by statistics derived from the altitude profile ensembles. The vertical extent of meaningful profile continuation is captured by the concept of extrapolation horizons defined as the boundaries of regions where the deviations remain below a prescribed error threshold. To demonstrate the methodology, the initial version of the DIPCont package presented in this paper contains a simplified LTI model with a small number of parameters. As a major source of variability, the pronounced change in temperature across the LTI is captured by self-consistent non-isothermal neutral-density and electron density profiles, constructed from scale height profiles that increase linearly with altitude. The resulting extrapolation horizons are presented for dual-satellite measurements at different inter-spacecraft distances but also for the single-satellite case to compare the two basic mission scenarios under consideration. DIPCont models and procedures are implemented in a collection of Python modules and Jupyter notebooks supplementing this report.

Low Earth Orbit determination in small satellite mission proposal for corona observation of close solar surface region

Low Earth Orbit determination in small satellite mission proposal for corona observation of close solar surface region

Structural response of Helianthus solar sail during attitude maneuvers

The Helianthus mission proposal is based on maintaining an artificial L1-type equilibrium point in the Sun-Earth gravitational field by means of a square solar sail, which should provide the required propulsive acceleration without any consumption of propellant. That vantage point would enable a scientific observation of the Sun and guarantee an effective monitoring of its activity, thus ensuring early warning in the event of catastrophic solar flares. Due to the intrinsic instability of artificial L1-type equilibrium points, the spacecraft dynamics is regulated by an advanced attitude control system based on electrochromic devices, which can adjust their optical properties through the application of a suitable electric voltage. In particular, a sliding mode controller has been recently proposed to commute the activation state of those devices by assuming that the solar sail (that is, the assembly of a large reflective membrane and its supporting booms) behaves like a perfectly rigid body. The aim of this work is to validate the predicted spacecraft dynamics by performing an accurate structural analysis of the solar sail under operating conditions through a numerical approach. In particular, a finite element method is used to evaluate the sail dynamic response to control torques in the context of some reorientation maneuvers.

Dynamic Predictive Quantization for Staggered SAR: Experiments With Real Data

Present and future spaceborne synthetic aperture radar (SAR) missions are designed to acquire an increasingly large amount of onboard data. This is a consequence of the use of large bandwidths, multiple polarizations, and the acquisition of large swath widths at fine spatial resolutions, which result in challenging requirements in terms of onboard memory and downlink capacity. In this scenario, SAR raw data quantization represents an essential aspect, as it affects the volume of data to be stored and transmitted to the ground as well as the quality of the resulting SAR products. Dynamic predictive block-adaptive quantization (DP-BAQ) is a novel technique, recently proposed by the authors, consisting of a low-complexity data compression method, and its application is particularly suitable for staggered SAR systems. DP-BAQ exploits the existing correlation among the azimuth raw data samples by applying linear predictive coding (LPC). This results in a data rate reduction of up to 25% with respect to state-of-the-art SAR quantization methods. In this letter, we test and validate the potential of DP-BAQ on airborne SAR data which emulates the system scenario of Tandem-L, a German Aerospace Center (DLR) mission proposal for a bistatic L-band system. For this purpose, an experimental SAR image has been acquired at the L-band by the airborne DLR flugzeug-SAR (F-SAR) sensor over the Kaufbeuren area, in Southern Germany. In order to simulate the staggered SAR acquisition mode, we implemented a dedicated resampling and filtering of the data. Our analyses confirm the effectiveness of DP-BAQ for efficient data volume reduction, exhibiting a consistent and promising performance when tested on areas characterized by different land cover types and backscatter statistics.

STELLA—Potential European contributions to a NASA-led interstellar probe

The discovery of a myriad of exoplanets in the past decades has revolutionized the understanding of our place in the Universe. How different are exoplants and do some of them harbor life, just like Earth? To do so, their parent stars must drive a stellar wind and carve what we call astrospheres into the surrounding interstellar medium. Astrospheres are ubiquitous in our immediate neighborhood and show similar structure to our heliosphere. Voyager 1 and 2, Ulysses, Cassini, and IBEX have shown that the interaction between interstellar medium and solar wind is much more complex and involved than previously believed. This stellar-interstellar interaction is key to understand astrospheres and the shielding they provide to the planetary systems they harbor. This article summarizes a whitepaper that was submitted to NASA’s 2023/2024 decadal survey which is being conducted by the US National Academies. It is based in parts on a proposal submitted to the European Space Agency (ESA) in response to its 2021 call for medium-class mission proposals. The whitepaper and this article propose to study the interaction described above in situ at the heliospheric boundaries and to explore the very local interstellar medium beyond. Furthermore, they highlight possible European contributions to a NASA-led Interstellar Probe (ISP).

The PI launchpad: Expanding the base of potential principal investigators across space sciences

The PI Launchpad attempts to provide an entry level explanation of the process of space mission development for new Principal Investigators (PIs). In particular, PI launchpad has a focus on building teams, making partnerships, and science concept maturity for a space mission concept, not necessarily technical or engineering practices. Here we briefly summarize the goals of the PI Launchpad workshops and present some results from the workshops held in 2019 and 2021. The workshop attempts to describe the current process of space mission development (i.e. space-based telescopes and instrument platforms, planetary missions of all types, etc.), covering a wide range of topics that a new PI may need to successfully develop a team and write a proposal. It is not designed to replace real experience but to provide an easily accessible resource for potential PIs who seek to learn more about what it takes to submit a space mission proposal, and what the first steps to take can be. The PI Launchpad was created in response to the high barrier to entry for early career or any scientist who is unfamiliar with mission design. These barriers have been outlined in several recent papers and reports, and are called out in recent space science Decadal reports.

Trajectory Analysis and Optimization of Hesperides Mission

A challenging problem from a technological viewpoint is to send a spacecraft at a distance of about 600 au from the Sun, comparable with that of the Sun’s gravitational focus (that is, the general relativistic focusing of light rays, whose minimum solar distance is obtained when the light rays are assumed to graze the Sun’s surface), and reach it in a time interval on the order of a human working lifetime. A suitably oriented telescope at that distance would be theoretically able to observe exoplanets tens of light years far away and possibly to discover new life forms. The transfer trajectory of this mission is rather complex and requires a close selection of a suitable propulsion system, which must be able to provide the probe with the necessary energy to cruise at a velocity greater than 10 au/year. An effective outline of the these concepts is given by the Hesperides mission, originally proposed by Matloff in 2014. An interesting aspect of this mission proposal is the combination of a nuclear electric propulsion system and a classical solar sail that are jointly exploited to reach the necessary solar system escape velocity. However, the trajectory analysis reported by Matloff is very simplified and is essentially concentrated on a rough estimate of the time required by the spacecraft to reach a distance of 600au. Starting from the Hesperides baseline mission proposal, including the vehicle mass distribution, the aim of this work is to give a detailed mission analysis in an optimal framework. In particular, the spacecraft minimum time trajectory is calculated with indirect methods and a parametric analysis is made to highlight the impact of the main design parameters on the total flight time. The simulations show a substantial reduction of the mission time when compared with the original study.

Developing compelling and science-focused mission concepts for NASA competed mission proposals

Since the mid 1990s, NASA has used a competitive selection process to initiate new mission concepts. These competed missions, which can be found at “NASA Solicitation and Proposal Integrated Review and Evaluation System” (NSPIRES) website [1], are motivated by high-value science with low implementation and cost risks. Selectable mission concepts require highly focused science approaches—delivering high quality science “on a budget.” Prospective Principal Investigators (PIs) need to convince NASA that the science they are proposing is both compelling and has high programmatic value.Unfortunately, many of these PIs are not trained in the communication skills needed for “selling” a mission concept to stakeholders. This requires a proposal that presents an investigation in an accessible, relatable, authentic, and believable way. It is the onus of the proposing PI to convince NASA of the value of their particular science concept in a competitive environment, addressing any pre-conceived notions reviewers might have about the concept's value, complexities, urgency, and other impediments to understanding.The importance of this can be seen in the NASA-sponsored PI Launchpad (Nov 2019 & Jun 2021) [2] which was designed to help early career scientists understand the skills, methods, processes, and resources needed to develop compelling science mission concepts; as well as in JPL's update to their concept maturity model (Jan 2020) which included the addition of Story and Strategy dimensions.This paper provides guidance to assist prospective PIs in developing compelling, science-focused mission concepts. It will provide direction for communicating concepts more clearly to make science objectives more relatable to both reviewers and a broader audience, improving the probability of selection.

Gravity Field Recovery and Error Analysis for the MOCASS Mission Proposal Based on Cold Atom Interferometry

Satellite missions providing data for a continuous monitoring of the Earth gravity field and its changes are fundamental to study climate changes, hydrology, sea level changes, and solid Earth phenomena. GRACE-FO (Gravity Recovery and Climate Experiment Follow-On) mission was launched in 2018 and NGGM (Next Generation Gravity Mission) studies are ongoing for the long-term monitoring of the time-variable gravity field. In recent years, an innovative mission concept for gravity measurements has also emerged, exploiting a spaceborne gravity gradio-meter based on cold atom interferometers. In particular, a team of researchers from Italian universities and research institutions has proposed a mission concept called MOCASS (Mass Observation with Cold Atom Sensors in Space) and conducted the study to investigate the performance of a cold atom gradiometer on board a low Earth orbiter and its impact on the modeling of different geophysical phenomena. This paper presents the analysis of the gravity gradient data attainable by such a mission. Firstly, the mathematical model for the MOCASS data processing will be described. Then numerical simulations will be presented, considering different satellite orbital altitudes, pointing modes and instrument configurations (single-arm and double-arm); overall, data were simulated for twenty different observation scenarios. Finally, the simulation results will be illustrated, showing the applicability of the proposed concept and the improvement in modeling the static gravity field with respect to GOCE (Gravity Field and Steady-State Ocean Circulation Explorer).

Influence of Low Europa Orbit design on gravity field recovery

The characterization of Europa's surface and interior ocean and ice shell is key to explore the habitability of the fourth largest moon of Jupiter. Europa Clipper will largely contribute to our knowledge of Europa with multiple dedicated flybys. However, global mapping can only be significantly improved by means of an orbiter with high inclination and low altitude, as it will be done in the case of Ganymede by JUICE. This was the strategy of several mission proposals (Joint Europa Mission, Jupiter Europa Orbiter, HADES). A specific difficulty in designing suitable orbits in the Jovian system is related to the orbit stability, which is highly impacted by the influence of Jupiter as a third body exerting strong perturbations on a Europa orbiter. This results in constraints for potential science orbits which would allow, e.g., for the determination of Europa's gravity field using radio tracking to the probe. In this presentation, we will analyze a set of different low Europa orbits and compare their scientific value for gravity field recovery. We will explore different orbital characteristics, with the possibility to use repetitive ground track orbits. The analysis will be performed based on closed-loop simulations using the planetary extension of the Bernese GNSS Software. We simulate realistic Doppler tracking data (2-way X-band Doppler range rate) from the Deep Space Network. These observations are then used to reconstruct the orbit as well as geodetic parameters, such as Europa gravity field parameters and the tidal Love number k2. We will discuss the quality of the retrieved solutions.

Near-infrared Reflectance of Rocks at High Temperature: Preliminary Results and Implications for Near-infrared Emissivity of Venus’s Surface

Abstract Light emitted from Venus’s surface can be viewed through spectral “windows” in its atmosphere, in the near-infrared (NIR) around 1000 nanometer (nm) wavelengths. The NIR emissivity of Venus’s surface can constrain rock types and their weathering state; emissivities can be measured directly or calculated from reflectances. We measured the reflectances of igneous and sedimentary rocks at Venus’s surface temperature, 400 °C–500 °C at 850 and 950 nm; samples were heated in a box furnace in air, illuminated by light-emitting diodes (LEDs), and imaged with a modified charge-coupled device (CCD) camera. Reflectances were also measured at 25 °C from 350 to 1400 nm. Rock reflectances at 850 and 950 nm and 400 °C–500 °C are nearly identical to those at 25 °C, except for the effects of nanophase hematite forming on some surfaces. Fresh basalts have reflectances (high and low temperatures) near 7.5%; a leucogranite similarly has reflectances near 50%. Pigmentary hematite has nearly identical reflectances at high- and low-temperature at these wavelengths. Pigmentary hematite appears dark brown 400 °C–500 °C because its absorption edge has shifted to beyond the limit of human vision. These rock reflectances imply that basalts should have emissivities near 0.9, and granite (and similar felsic rocks) should have lower emissivities ∼0.5. Thus, basalt and felsic rock should be easily distinguished in NIR emissivity measurements of Venus’s surface, such as are baselined in recent Venus mission proposals. Other sedimentary rocks should have even lower emissivities: quartz sand at around ∼0.3, and anhydrite as low as 0.1.

Measuring the spectrum of primordial gravitational waves with CMB, PTA and laser interferometers

We investigate the possibility of measuring the primordial gravitational wave (GW) signal across 21 decades in frequencies, using the cosmic microwave background (CMB), pulsar timing arrays (PTA), and laser and atomic interferometers. For the CMB and PTA experiments we consider the LiteBIRD mission and the Square Kilometer Array (SKA), respectively. For the interferometers we consider space mission proposals including the Laser Interferometer Space Antenna (LISA), the Big Bang Observer (BBO), the Deci-hertz Interferometer Gravitational wave Observatory (DECIGO), the μAres experiment, the Decihertz Observatory (DO), and the Atomic Experiment for Dark Matter and Gravity Exploration in Space (AEDGE), as well as the ground-based Einstein Telescope (ET) proposal. We implement the mathematics needed to compute sensitivities for both CMB and interferometers, and derive the response functions for the latter from the first principles. We also evaluate the effect of the astrophysical foreground contamination in each experiment. We present binned sensitivity curves and error bars on the energy density parameter, ΩGWh2, as a function of frequency for two representative classes of models for the stochastic background of primordial GW: the quantum vacuum fluctuation in the metric from single-field slow-roll inflation, and the source-induced tensor perturbation from the spectator axion-SU(2) inflation models. We find excellent prospects for joint measurements of the GW spectrum by CMB and space-borne interferometers mission proposals.

Proposed Tasks of Enceladus Missions’ Instrumentation in the Context of Their Astrobiological Goals

Enceladus, Saturnian satellite, is a very significant object for astrobiologists due to the presence of liquid water that forms the ice-covered ocean. Water ice geysers escape from the south pole region through cracks in the ice shield. During the Cassini flight, the probe took samples of plumes matter recognizing besides other methane and molecular hydrogen. Since then, hypotheses have been formulated that life forms similar to those found in the Lost City Hydrothermal Field in the Atlantic ocean bottom may occur near Enceladus’ hydrothermal chimneys. In our work, we analyzed the possibility of a microbial factor detection in the Enceladus geysers. We used as model organisms selected extremophiles. We investigated multi-spectral cameras and mass spectrometers intended for use in mission proposals to Enceladus: Enceladus Orbiter, Enceladus Life Finder, The Explorer of Enceladus and Titan and THEO mission. The review pointed that the configuration of mass spectrometers and the proposed parameters of scientific orbits are appropriate for detecting volatile organic compounds corresponding to selected microorganisms such as aldehyde, ethanol, benzene, toluene, indole, or violacein. The possible presence of a microbiological component with physical dimensions in the order of several micrometres can only be observed for areas of geyser formation at their higher density (> 10 ppm) and with the occurrence of the “snowing microbes” phenomenon. We have found that particularly useful optical channels are 780–975 nm, 860–910 nm, and 5.0–5.3 µm.

Simulating Mars Drilling Mission for Searching for Life: Ground-Truthing Lipids and Other Complex Microbial Biomarkers in the Iron-Sulfur Rich Río Tinto Analog.

Sulfate and iron oxide deposits in Río Tinto (Southwestern Spain) are a terrestrial analog of early martian hematite-rich regions. Understanding the distribution and drivers of microbial life in iron-rich environments can give critical clues on how to search for biosignatures on Mars. We simulated a robotic drilling mission searching for signs of life in the martian subsurface, by using a 1m-class planetary prototype drill mounted on a full-scale mockup of NASA's Phoenix and InSight lander platforms. We demonstrated fully automated and aseptic drilling on iron and sulfur rich sediments at the Río Tinto riverbanks, and sample transfer and delivery to sterile containers and analytical instruments. As a ground-truth study, samples were analyzed in the field with the life detector chip immunoassay for searching microbial markers, and then in the laboratory with X-ray diffraction to determine mineralogy, gas chromatography/mass spectrometry for lipid composition, isotope-ratio mass spectrometry for isotopic ratios, and 16S/18S rRNA genes sequencing for biodiversity. A ubiquitous presence of microbial biomarkers distributed along the 1m-depth subsurface was influenced by the local mineralogy and geochemistry. The spatial heterogeneity of abiotic variables at local scale highlights the importance of considering drill replicates in future martian drilling missions. The multi-analytical approach provided proof of concept that molecular biomarkers varying in compositional nature, preservation potential, and taxonomic specificity can be recovered from shallow drilling on iron-rich Mars analogues by using an automated life-detection lander prototype, such as the one proposed for NASA's IceBreaker mission proposal.

The Complex Molecules Detector (CMOLD): A Fluidic-Based Instrument Suite to Search for (Bio)chemical Complexity on Mars and Icy Moons.

Organic chemistry is ubiquitous in the Solar System, and both Mars and a number of icy satellites of the outer Solar System show substantial promise for having hosted or hosting life. Here, we propose a novel astrobiologically focused instrument suite that could be included as scientific payload in future missions to Mars or the icy moons: the Complex Molecules Detector, or CMOLD. CMOLD is devoted to determining different levels of prebiotic/biotic chemical and structural targets following a chemically general approach (i.e., valid for both terrestrial and nonterrestrial life), as well as their compatibility with terrestrial life. CMOLD is based on a microfluidic block that distributes a liquid suspension sample to three instruments by using complementary technologies: (1) novel microscopic techniques for identifying ultrastructures and cell-like morphologies, (2) Raman spectroscopy for detecting universal intramolecular complexity that leads to biochemical functionality, and (3) bioaffinity-based systems (including antibodies and aptamers as capture probes) for finding life-related and nonlife-related molecular structures. We highlight our current developments to make this type of instruments flight-ready for upcoming Mars missions: the Raman spectrometer included in the science payload of the ESAs Rosalind Franklin rover (Raman Laser Spectrometer instrument) to be launched in 2022, and the biomarker detector that was included as payload in the NASA Icebreaker lander mission proposal (SOLID instrument). CMOLD is a robust solution that builds on the combination of three complementary, existing techniques to cover a wide spectrum of targets in the search for (bio)chemical complexity in the Solar System.

Circumbinary exoplanets and brown dwarfs with the Laser Interferometer Space Antenna

Aims. We explore the prospects for the detection of giant circumbinary exoplanets and brown dwarfs (BDs) orbiting Galactic double white dwarfs (DWDs) binaries with the Laser Interferometer Space Antenna (LISA). Methods. By assuming an occurrence rate of 50%, motivated by white dwarf pollution observations, we built a Galactic synthetic population of P-type giant exoplanets and BDs orbiting DWDs. We carried this out by injecting different sub-stellar populations, with various mass and orbital separation characteristics, into the DWD population used in the LISA mission proposal. We then performed a Fisher matrix analysis to measure how many of these three-body systems show a periodic Doppler-shifted gravitational wave perturbation detectable by LISA. Results. We report the number of circumbinary planets (CBPs) and BDs that can be detected by LISA for various combinations of mass and semi-major axis distributions. We identify pessimistic and optimistic scenarios corresponding, respectively, to 3 and 83 (14 and 2218) detections of CBPs (BDs), observed during the length of the nominal LISA mission. These detections are distributed all over the Galaxy following the underlying DWD distribution, and they are biased towards DWDs with higher LISA signal-to-noise ratio and shorter orbital period. Finally, we show that if LISA were to be extended for four more years, the number of systems detected will be more than doubled in both the optimistic and pessimistic scenarios. Conclusions. Our results present promising prospects for the detection of post-main sequence exoplanets and BDs, showing that gravitational waves can prove the existence of these populations over the totality of the Milky Way. Detections by LISA will deepen our knowledge on the life of exoplanets subsequent to the most extreme evolution phases of their hosts, clarifying whether new phases of planetary formation take place later in the life of the stars. Such a method is strongly complementary to electromagnetic studies within the solar region and opens a window into the investigation of planets and BDs everywhere in the entire Galaxy, and possibly even in nearby galaxies in the Local Group.

Future space drilling and sample acquisition: A collaborative industry-government workshop

A workshop on Planetary Drilling and Sample Acquisition was held at NASA-Goddard Space Flight Center, its purpose was to bring together the past decade of research and development results to define a framework for consistently and completely describing sample acquisition tasks for future Solar System missions, to survey the current state of knowledge of sample acquisition methods, and for each high priority application of sample acquisition technology, determine what had been demonstrated thus far vs. unaddressed areas. Combining inputs from government, academic and industrial participants, the workshop concluded that drilling missions that go 1-2 m deep (on the Moon, Mars, Europa or small bodies) are now feasible to propose in the 2020s, with potentially-high scientific payoff. Further, in developing complex sample acquisition systems for Solar System targets, the workshop agreed that both chamber tests and field tests at terrestrial analog sites are required. The workshop proposed adding cross-contamination and planetary protection requirements explicitly to instrument and surface mission flight calls, and also to add these as part of the technology readiness evaluation for NASA mission proposals.

Future gamma-ray missions’ polarimetric prospects

High-energy astrophysics polarimetry may significantly benefit from e-ASTROGAM and from AMEGO mission proposals, since to date limited polarimetric measurements were performed in this domain, exclusively under 1 MeV. The polarimetric potential of both missions was analyzed in the Compton regime by Monte Carlo mass model simulations with MEGAlib toolkit. The performance of e-ASTROGAM was analyzed by simulating Si tracker and calorimeter alternative configurations and detection materials, within missions’ volume, mass and power margins. The modulation polarimetric factor, Q, and the MDP were calculated for different polarized source types and for variable incidence angle measurement conditions. Finally, the polarimetric performances of both instruments was compared and analyzed. Q modulation factors obtained ranged between ~0.2 and ~0.4 in the 0.2–2.0 MeV band and MDP ~0.65% was estimated for a 100% polarized Crab type source, 1 Ms. observation time and 3σ significance.