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International Planetary Probe Workshop (IPPW)

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Publication Search Results

Now showing 1 - 10 of 119
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    A Brief History of Mars Entry, Descent and Landing: 20 Minutes of Terror Followed by 5 Minutes of Q&A
    (Georgia Institute of Technology, 2008-06-27) Manning, Robert
    Starting with the valiant attempts by the USSR to land the Mars 2 & 3 landers in 1971 through last month's Phoenix landing, Rob Manning will review the wild history of Mars landing attempts.
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    Why Mars Sample Return Will Never Happen
    (Georgia Institute of Technology, 2008-06-27) Adler, Mark
    The ongoing quest to bring to Earth selected samples of the surface of Mars has repeatedly run into what appear to be insurmountable obstacles. The mission continues to be delayed at rates greater than one year per year. Though it is the highest priority objective for Mars exploration, it is the least likely mission to be mounted. So what's the problem here? We will discuss the many hurdles, both technical and programmatic, that a successful Mars Sample Return mission will have to overcome.
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    Exploring Venus with Balloons - Science Objectives and Mission Architectures for Small and Medium-Class Missions
    (Georgia Institute of Technology, 2008-06-26) Hall, Jeffery L. ; Baines, Kevin H. ; Zahnle, Kevin J. ; Limaye, Sanjay ; Atreya, Sushil K.
    Following the trailblazing flights of the 1985 twin Soviet VEGA balloons, missions to fly in the skies of Venus have been proposed to both NASA's Discovery Program and ESA's Cosmic Visions amd are currently being planned for NASA's next Frontiers Mission opportunity. Such missions will answer fundamental science issues highlighted in a variety of high-level NASA-authorized science documents in recent years, including the Decadal Study, various NASA roadmaps, and recommendations coming out of the Venus Exploration Analysis Group (VEXAG). Such missions would in particular address key questions of Venus's origin, evolution, and current state, including detailed measurements of (1) trace gases associated with Venus's active photo- and thermo-chemistry and (2) measurements of vertical motions and local temperature which characterize convective and wave processes. As an example of what can be done with small and medium class missions (less than $900M and $500M, respectively), the Venus Aerostatic-Lift Observatories for in-situ Research (VALOR) Discovery and New Frontiers mission concepts will be discussed. Floating in Venus's rapid windstream near an altitude of 55 km, VALOR's twin balloon-borne aerostats will sample rare gases and trace chemicals and measure vertical and horizontal motions and cloud aerosols within Venus's dynamic middle cloud layer. Each balloon will explore a distinctive dynamical/meteorological region within Venus's energetic atmosphere as each circles the globe for over a week, with one drifting in the cloudy north polar region and the other flying in the less-cloudy but more convective temperate region. The New Frontiers concept would carry several drop sondes that would provide vertical profiles from 55 km down to the surface of temperature, pressure, winds, and the abundances of key reactive gases including SO2, CO, and H2O. In addition, each drop sonde would obtain stereoscopic images and spectra of the surface. Each of these VALOR missions would test a variety of scenarios for the origin, formation, and evolution of Venus by sampling all the noble gases and their isotopes, especially the heaviest elements never reliably measured previously, xenon and krypton. Riding the gravity and planetary waves of Venus a la the VEGA balloons in 1985, the VALOR balloons would sample in particular the chemistry and dynamics of Venus's sulfur-cloud meteorology. Tracked by an array of Earth-based telescopes, zonal, meridional, and vertical winds would be measured with unprecedented precision. Such measurements will help in developing our fundamental understanding of (1) the circulation of Venus, including the role of waves in powering the planet's poorly-understood super-rotation, (2) the nature of Venus's sulfur cycle, key to Venus's current climate, and (3) how Earth's neighbor formed and evolved over the aeons.
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    ExoMars: ESA's Mission to Search for Signs of Life on the Red Planet
    (Georgia Institute of Technology, 2008-06-26) Elfving, A. ; Haldemann, A. ; Gardini, B. ; McCoy, D. ; Gianfiglio, G. ; Kminek, G. ; Vago, Jorge ; Baglioni, P. ; Trautner, Roland
    Establishing whether life ever existed, or is still active on Mars today, is one of the outstanding scientific questions of our time. In order to timely address this important goal, within the framework of its Aurora Exploration Programme, the European Space Agency (ESA) plans to launch the ExoMars mission in 2013. ExoMars will deploy a Rover carrying a comprehensive suite of analytical instruments dedicated to exobiology research: the Pasteur payload. The Rover will travel several kilometres searching for traces of past and present signs of life. It will do this by collecting and analysing samples from within rock outcrops and from the subsurface, down to a depth of 2 m. The very powerful combination of mobility and access to subsurface locations, where organic molecules may be well-preserved, is unique to this mission. The ExoMars Rover mission will be complemented by the Humboldt instruments on the Lander, dedicated to environment and geophysics investigations. ExoMars will rely on a heavy launcher (Ariane 5 or Proton M) to send a Composite, consisting of a Carrier and the Descent Module, onto Mars. The Composite will settle into a Mars parking orbit, from where (when conditions are appropriate) the Descent Module will be released. Upon entering the Martian atmosphere, a heat shield will break the initial descent, followed by parachutes, and a liquid propulsion system. From a height of ~10 m, the Lander will be dropped onto the ground. Vented airbags will cushion the final impact, without bounces. The latter is a new European technology to be developed for this mission. The Rover will be deployed and operated for a nominal 180 sols. The Lander will also have a nominal lifetime of 180 sols. Mission extensions will be possible provided the surface elements are in good health. Latitudinal bands between -5 degrees and 45 degrees can be targeted for landing, ensuring that the mission is flexible enough to accommodate interesting new sites based on latest available information from on-going Mars orbital missions. The mission's data relay capability will be provided by a NASA orbiter; however, ESA will evaluate the possibility to use the ExoMars Carrier as a data relay orbiter. This paper will briefly describe the mission's science content and current level of definition.
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    Ablation of Pica-Like Material: Surface or Volume Phenomenon?
    (Georgia Institute of Technology, 2008-06-26) Lachaud, Jean ; Mansour, Nagi Nicolas
    The ablation of the char layer in ablative material is usually described in term of recession velocity of the overall surface. This description is valid for dense materials. However, the recession of the average surface in porous materials may not recede uniformly, but the individual fibers may progressively vanish. In the second regime, ablation is no longer a surface phenomenon, but is volumetric. Seen from a surface point of view, three important consequences follow this volume ablation regime: (1) the effective reactivity of the material is significantly increased, (2) the material weakens in volume and is subject to strong mechanical erosion (spallation), and (3) the ablation enthalpy distributed in volume modifies the thermal response of the material. In this regime, surface ablation models should be replaced by volume ablation models for a more accurate description of the outer layer of the material. In the presentation, a first attempt to couple volume ablation with pyrolysis is done using a multiscale approach. In an effort to derive phenomenological models for the volume ablation regime, three-dimensional (3D) simulations of isothermal ablation in air of a low-density material made of carbon fibers distributed randomly are performed. A parametric study shows that ablation is either a surface or a volume phenomenon depending on the value of Thiele number (reaction/diffusion competition inside the porous media), when advection due to pyrolysis and thermal gradients are neglected. A macroscopic model for volume ablation is derived analytically using homogenization (averaging). The model is a set of partial differential equations, similar to traditional pyrolysis models. Simulations of coupled pyrolysis and volume ablation are presented. The possible spallation of PICA due to volume ablation during Stardust re-entry is discussed under the light of this model.
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    ExoMars Mission Analysis and Design from Mars Arrival to Landing
    (Georgia Institute of Technology, 2008-06-26) Anselmi, Alberto ; Gittins, David ; Northey, David ; Luis Cano, Juan ; Haya Ramos, Rodrigo ; Portigliotti, Stefano
    ExoMars is ESA's next mission to planet Mars. The project is currently undergoing Phase B2 studies under ESA management. In that context, DEIMOS is responsible for the Mission Analysis support to Thales Alenia Space Italy as ExoMars Prime Contractor, covering all mission phases, including launch, interplanetary, Mars orbit injection and orbiting, down to entry, descent and landing (EDL). Tessella (previously under the name Analyticon) supports DEIMOS in the area of Descent and Landing Analyses. The current mission baseline is based on an Ariane 5 launch in 2013 of a spacecraft Composite made up of a Carrier Module (CM) and a Descent Module (DM). The trajectory profile is characterised by: a) direct transfer to Mars with an intermediate deep space manoeuvre (DSM), b) insertion into a 4-sol Mars waiting orbit (WO) and c) Composite descent from orbit, initiated by the Carrier, which then separates and burns up in the Martian atmosphere, while the DM goes on to complete the descent and landing. The role of the EDL Mission Analysis and Design is to provide support to the System Design Team for preparing the specification of the EDL System (EDLS) components, namely the heat shield, the two-stage parachute system, the throttleable retrorocket system and the vented airbags. At the beginning of Phase B2, a complete design loop of the DM is available, which means that the feasibility of the EDLS specification has been assessed through a detailed design of its components. Now, the Mission Analysis and Design activity has to provide support to the next design loop of the DM in which some of the mission requirements have been revised. In addition, the greater knowledge of the system after the first complete design loop allows a refinement of the EDL mission design methods and tools. The objective of this paper is to present the current mission design of the EDL phase of the ExoMars mission, focusing on the Mars Orbit Insertion (MOI) targeting up to the touchdown. Some specific analyses that are addressed in the paper are outlined in the following paragraphs. The first one is related to the connection between the arrival and the EDL phase. Landing from orbit rather than from infinity allows optimisation of the landing epoch w.r.t. solar conjunctions, the Mars Global Dust Storm Season, and other criteria. The evolution of the WO over several months in orbit before descent is a function of the targeting parameters (landing site and entry angle) and the arrival epoch. The consequence is that the EDL Phase is tightly linked, via the Waiting Orbit, to the Mars orbit insertion conditions. In other words, once the target landing site (and particularly the landing latitude) is selected, the target point in the B-plane of the arrival hyperbola will be fixed. After achieving the injection conditions in the proposed 4-sol orbit, the spacecraft will be required to wait in orbit until the foreseen Mars solar longitude is achieved for landing. In order to tackle this problem, the EDL mission design has been extended up to the Mars Orbit Insertion (MOI) in such a way that an end-to-end, i.e. continuous, mission profile from the MOI to touchdown is obtained. The orbit strategy prior to arrival to the Entry Interface Point (EIP, 120 km altitude) is based on the reduction of the trajectory dispersions at EIP. This is achieved in several ways, among others minimising the errors in the implementation of the DM targeting manoeuvre (DMTM) and reducing the size of the DMTM. The first effect is optimised by reducing as much as possible the errors in implementation of the actuator and achieving the best possible orbit knowledge through Orbit Determination (OD). The second effect is reduced by staging the reduction in perigee height, first reducing the perigee height to 250 km and in the next orbit finally targeting to the expected EIP. The result is that the dispersion at the EIP significantly reduces and the landing accuracy is below 25 km for the steepest entries compatible with the entry constraints (heat flux, heat load, load factor, drogue deployment window). These values have been verified by detailed end-to-end 3-DOF Monte Carlo simulations from the DMTM up to landing. The Global Entry Corridor (GEC) method has been extensively applied to identify the sizing trajectories for the design and to evaluate the feasibility of selected landing sites. Combination of the GEC with the Engineering Constraints (terrain slopes and footprint size) and Scientific Requirements allows the identification of feasible landing sites. The above mentioned link between the B-plane targeting and the EDL phase is considered in the GEC analyses. This paper also addresses the detailed evaluation of the performance of the mission in selected landing sites through detailed end-to-end Monte Carlo analyses (from DMTM to touchdown). Multibody simulations for the descent phase have been also run to verify the stability of the system and the sensitivity to perturbations (gust). These results serve not only as a verification of the mission design but also as a validation of the design methods and tools. The use of a parametric DLS sizing tool is foreseen to support further optimisation of the descent and landing system, in particular the allocation between the two stages of the parachute system and the retrorockets system.
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    Mars Science Laboratory: The Next Rover
    (Georgia Institute of Technology, 2008-06-26) Meyer, Michael D.
    The Mars Science Laboratory rover represents firsts in many aspects for interplanetary exploration. To get the rover to the planet's surface, the rover is winched down from the thrusters, substituting wheels for the usual platform, legs (or air bags) and off-ramp. The mass savings have afforded a larger rover and accompanying instrument payload. The landed platform, which is the landed rover, will carry an analytical laboratory with two instruments of unprecedented capability, a Gas Chromatograph/Mass Spectrometer, which includes a Harriet cell Tunable Laser System, and X-Ray Diffractometer, an instrument type not flown since the Viking landers in 1976. In addition, the other instruments represent innovative improvements with significant increases in capability. Of particular note, an instrument new to planetary exploration, is ChemCam, a laser induced breakdown spectroscope for remote sensing of chemistry and micro-imaging. This enables elemental/chemical composition to be measured at a meters distant, greatly expanding the survey capability. The details of MSL's approaches and the implications for future missions will be discussed.
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    Challenges for the Heatshield Development of Sample Return Missions - An Overview on European Sample Return Studies and Requirements
    (Georgia Institute of Technology, 2008-06-26) Santovincenzo, A. ; Ritter, Heiko ; Walpot, L.
    The atmospheric entry of the Earth return capsule of sample return mission is one of the most critical phases of sample return missions. The Earth return from extraterrestrial bodies (e.g. Mars, comets or asteroids) involves a hyperbolic entry with entry velocities of typically above 12 km/s, resulting in peak heat fluxes in the order of 10 MW/m(2) and heat loads up to 200 MJ/m(2). While during a classical re-entry from Earth-orbit the heat flux is basically limited to convective fluxes, additionally radiative fluxes become increasingly important at entry velocities above 12 km/s. In addition, since the Earth return capsule is subject to a "double" delta-V (to the object and back to Earth), the return capsule and its heatshield have to conform to a very stringent mass budget. Further, surface recession due to ablation and abrasion effects needs to remain limited in order to guarantee the aerodynamic stability. This requires the availability of a highly efficient light-weight ablator material. In a dedicated study a screening of existing European ablators was performed to assess their suitability. Unfortunately, it turned out that none of the materials, which were developed in front of very different requirements, is suitable to sustain the very high heat fluxes while coping with the mass requirement. Dedicated development is therefore initiated to tailor materials towards the stringent requirements. Another important aspect is the availability of plasma facilities for the qualification of the materials. Such high enthalpy facility needs to be able to reproduce the extreme heat fluxes at representative dynamic pressure levels and simulating the high radiation level. Additionally it would be beneficial to assess the dynamic stability of the entry capsule using free flight ballistic tests. The paper will provide an overview on the main challenges involved in the development of the heatshield for the Earth re-entry capsule of sample return missions, resulting from different ESA studies to Mars and asteroids. This will include system aspects, the choice of the TPS material and its qualification, flight path stability and reliability. Preliminary technology roadmaps will also be presented.
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    The Phoenix Mission Lands on Mars
    (Georgia Institute of Technology, 2008-06-26) Smith, Peter
    Phoenix will land on the arctic plains of Mars on May 25, 2008. The team of the University of Arizona, the Jet propulsion Lab, and Lockheed Martin have spent a considerable effort in orchestrating a robust approach, entry, descent, and landing sequence of events. Contingency maneuvers are planned for every critical event such that the team can respond rapidly with tested procedures to any potential anomaly. Once on the surface, we will evaluate the power levels, communication links, and thermal state to assess the health of the lander and its ability to complete our mission goals. By the time of the conference, panoramic images and the results of the analysis of the first surface samples of soil should be available. In addition, the weather patterns will be monitored during the active summer season. The mission will continue for several months while we dig down to the ice boundary and sample both ice and soil to understand the mineralogy, chemistry, and the potential for habitability of this unexplored region of Mars.
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    Some Options for In Situ Geochemical and Geophysical Experiments in the Titan Environment by TandEM/TSSM
    (Georgia Institute of Technology, 2008-06-26) Ball, Andrew J.
    We present concepts for in situ instrumentation for Titan aerial platforms, probes, landers and penetrators, in the context of the TandEM mission proposal in ESA's Cosmic Vision programme and TSSM in NASA's New Frontiers program. These include 1) geochemical instrumentation for aerosol analysis, GCMS of surface materials, stable isotope analysis and trace gas detection, and 2) geophysical / meteorological instrumentation for studies of atmospheric science and energy balance. These concepts draw upon heritage and lessons learned from the Huygens Surface Science Package and Atmospheric Structure Instrument, the Beagle 2 Gas Analysis Package and the Ptolemy evolved gas analyser on the Philae comet lander.