Space Missions

A set of analysis tools has been created in a community-based team environment to support ground resource allocation planning. This new tool, called GRAPE, combines analysis, monitoring, and search capability into an existing community environment where wikis, blogs, document libraries, calendars, discussion forums, lists, progress management, and email repositories are available in a web site which assists users with their communication, analysis, and collaboration needs.

Long-duration missions (e.g. to the Moon, asteroids, or Mars) require astronauts to collaborate and interact with complex computerized equipment and facilities under dynamic and hazardous conditions. The Mission Execution Crew Assistant (MECA) comprises crew support that acts as an "electronic partner" (ePartner), helping the crew to take care of their mental and social conditions and to schedule crew activities. We have developed a simple prototype of MECA which we use to test MECA's functionalities in analogue environments where test participants are placed in isolation for longer periods of time.

Ongoing and planned smallsat programs within NASA, the DoD, and academia have indicated a need to be able to routinely and efficiently operate multiple small spacecraft in support of science and technology missions. However, as the number of these missions is expected to grow rapidly, the associated costs to develop and operate unique ground control stations, tools, and networks may become prohibitive to the sponsoring organizations or universities. In order to inform and raise the awareness of the smallsat space operations community, the University of Hawai'i, NASA Ames Research Center, San Jose State University (SJSU) and American Institure of Aeronautics and Astronautics (AIAA) held a workshop entitled Plug 'n' Play Mission Operations (PPMO) which held May 16-17, 2011 at the SJSU campus in San Jose, California. The purpose of the workshop was to foster collaboration and leveraging of existing and developing capabilities that may be collectively utilized by the smallsat community for space operations. Although the emphasis of the workshop was on small satellites, many of the techniques discussed would be applicable to large spacecraft mission operations as well. The workshop explored the adoption of standards and existing capabilities as well as the creation of new technologies that will enable space mission developers to plan, design, and operate their spacecraft using a common architecture in order to reduce cost and overall mission risk. The PPMO workshop investigated the various needs of the smallsat communities (military, civil and educational space) and also touched on existing systems and capabilities (such as GSFC's GMSEC, JPL's AMMOS, and NRL's CGA used in the MC3 program) and those under development (such as HSFL's COSMOS and ESA's GENSO). The workshop also held facilitated discussions organized into categories along the lines of Approaches (programmatic and related issues), Implementation (technical solutions and architectures), and Applications (concept of operations, mission types and users). This paper presents the results of this workshop and the path forward. TABLE OF CONTENTS 1. INTRODUCTION .

The goals and system-level requirements for the next generation aerospace vehicles emphasize safety, reliability, low-cost, and robustness rather than performance. Technologies, including new materials, design and analysis approaches, manufacturing and testing methods, operations and maintenance, and multidisciplinary systems-level vehicle development are key to increasing the safety and reducing the cost of aerospace launch systems. This chapter identifies the goals and needs of the next generation or advanced aerospace vehicle systems.

The recent improvements achieved in the Homoepitaxial Chemical Vapour Deposition technique have led to the production of highquality detector-grade single-crystal diamonds. Diamond-based detectors have shown excellent performances in UV and X-ray detection, paving the way for applications of diamond technology to the fields of space astronomy and high-energy photon detection in harsh environments or against strong visible light emission. These applications are possible due to diamond's unique properties such as its chemical inertness and visible blindness, respectively. Actually, the development of linear array detectors represents the main issue for a full exploitation of diamond detectors. Linear arrays are a first step to study bi-dimensional sensors. Such devices allow one to face the problems related to pixel miniaturisation and of signal read-out from many channels. Immediate applications would be in spectroscopy, where such arrays are preferred. This paper reports on the development of imaging detectors made by our groups, starting from the material growth and characterisation, through the design, fabrication and packaging of 2 Â n pixel arrays, to their electro-optical characterisation in terms of UV sensitivity, uniformity of the response and to the development of an electronic circuit suitable to read-out very low photocurrent signals. The detector and its electronic read-out were then tested using a 2 Â 5 pixel array based on a single-crystal diamond. The results will be discussed in the framework of the development of an imager device for X-UV astronomy applications in space missions.

In light of the renewed international interest in lunar exploration, including plans for setting up a permanent human outpost on the Moon, the need for next generation earth-based human space mission simulators has become inevitable and urgent. These simulators have been shown to be of great value for medical, physiological, psychological, biological and exobiological research, and for subsystem test and development, particularly closed-loop life support systems. The paper presents a summary of a survey of past, present and future human space mission simulators. In 2006, the Vienna based company Liquifer Systems Group (LSG) conducted an in-depth survey, for a European Space Agency (ESA) commissioned Phase-A contract involving a Design Study for a Facility for Integrated Planetary Exploration Simulation (FIPES). The survey data served as reference material for development of the FIPES architecture and, more importantly the application of the data ensured that the Systems Requirements reviewed and amended as part of the FIPES Study fully reflected the design, experience, and lessons learned from the use of such facilities. The paper addresses a hitherto unfulfilled need: a comprehensive, comparative survey of most, if not all, simulators to date. It is a condensed and updated version of the detailed ESA Technical Report produced for the FIPES Study. It presents a comparative analysis of simulator characteristics and consolidated summaries for each simulator classified into (1) site and purpose, (2) key technical data, (3) scientific and medical research functions, and (4) technology test and development functions. It is beyond the scope of this paper to provide details for all twenty-seven simulators surveyed. Therefore, the paper presents selected summaries of three sets of relatively recent simulation campaigns, one European, one American and the other Russian-International. The paper concludes with excerpts of lessons learned from these campaigns.

The authors describe some new estimates concerning the recently proposed SEE (Satellite Energy Exchange) experiment for measuring the gravitational interaction parameters in space. The experiment entails precision tracking of the relative motion of two test bodies (a heavy "Shepherd", and a light "Particle") on board a drag-free capsule. The new estimates include: (i) the sensitivity of particle trajectories and G

In the search for extraterrestrial life, the focus has predominantly been on chemical signatures and the presence of water. However, a novel approach could involve the investigation of electromagnetic waves and magnetic fields emitted by exoplanets. This theory proposes that similar electromagnetic patterns to those found on Earth could indicate potential habitability.

-Anewppdsion concept for high AV space missions, termed LABS (Liquid Annular Re&or System), uses liquid nuclear fuel elements to heat hyw ppllant to very high temperatures (4000 K). The molten fuel is contained in a lower-temperature solid container which rotates to stabilize and hold in the liquid layer by centripctal force. Containment of ultra high temperature molten refractories, using this mcth@ has been expcrimcntally demonstrated by AV. Grosse. The specitic imp&c of a rocket exha&ng hydrogen at 6000 K is 2000 seconds, approximately double that of solid-core nuclear rockets. A LARS-@we14 space probe could accomplish extra-solar missions to 5.50 A.U. in approximately 35 year; reserved.

EBEX (the E and B EXperiment) is a balloon-borne telescope designed to measure the polarisation of the cosmic microwave background radiation. During a two week long duration science flight over Antarctica, EBEX will operate 768, 384 and 280 spider-web transition edge sensor (TES) bolometers at 150, 250 and 410 GHz, respectively. The 10-hour EBEX engineering flight in June 2009 over New Mexico and Arizona provided the first usage of both a large array of TES bolometers and a Superconducting QUantum Interference Device (SQUID) based multiplexed readout in a space-like environment. This successful demonstration increases the technology readiness level of these bolometers and the associated readout system for future space missions. A total of 82, 49 and 82 TES detectors were operated during the engineering flight at 150, 250 and 410 GHz. The sensors were read out with a new SQUID-based digital frequency domain multiplexed readout system that was designed to meet the low power consumption and robust autonomous operation requirements presented by a balloon experiment. Here we describe the system and the remote, automated tuning of the bolometers and SQUIDs. We compare results from tuning at float to ground, and discuss bolometer performance during flight.

This article investigates a hypothesis that solar sunspot variability perturbs Van Allen Belt particle dynamics, with cascading effects on Earth's electromagnetic environment and surface systems. While emphasizing established solar-terrestrial physics, we explore underexamined pathways-such as magnetosphere-core inductive heating and geomagnetic-climate linkages-as potential avenues for interdisciplinary research.

Atomic clocks are an outstanding tool for the experimental verification of general relativity and more generally for fundamental astronomy (VLBI, pulsar timing, navigation, etc). Recent years have seen a rapid improvement in the performance of such clocks, promising new improved tests of relativity, in particular onboard terrestrial and interplanetary space missions. We present the scientific motivations of such tests taking the ACES Salomon et al. and SAGAS Wolf et al. (2009) projects as particular examples.

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The nozzle is an important component of the rocket motor system, and a rocket’s overall performance is highly reliant on its aerodynamic design. The nozzle contour can be meticulously shaped to improve performance significantly. The design and shape of rocket nozzles have evolved over the last several decades as a result of extensive research. The nozzle design is composed of two components, an integrated throat, an entry and an exit cone, and a thermal protection system. The Bell Nozzle is designed to provide clearance space for placing the ITE and exit cone, with a cone inflection angle of 16 and a thermal protection system. This paper intends to review and summarize all such developments. Small-scale engine testing allows for the analysis of rocket nozzle materials, but the history of nozzle surface temperature and thermal stress may be adversely affected by side effects. The review focuses primarily on the nozzle shape which has the largest radiative flux past the neck, but the ...

In 1995, Mayor and Queloz [a] detected for the first time a planet orbiting a nearby star (15.4 parsecs). Since then, the interest in the detection of extra-solar planets, in order to learn about the origin, evolution, and composition of planetary systems, has grown tremendously and ...

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet's birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25-7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and welldefined planet sample within its 4-year mission lifetime. Transit, eclipse and phasecurve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10-100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H 2 O, CO 2 , CH 4 NH 3 , HCN, H 2 S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performedusing conservative estimates of mission performance and a

The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10 -4 relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 μm with a goal of covering from 0.4 to 16 μm. Only modest spectral resolving power is needed, with R~300 for wavelengths less than 5 μm and R~30 for wavelengths greater than this. The transit

The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are?In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spi...

The technical personnel in the SEMA office are working to provide the highest degree of value-added activities to their support of the NASA Langley Research Center mission. Management perceives that reliability analysis tools and an understanding of a comprehensive systems approach to reliability will be a foundation of this change process. Since the office is involved in a broad range of activities supporting space mission projects and operating activities (such as wind tunnels and facilities), it was not clear what reliability tools the office should be familiar with and how these tools could serve as a flexible knowledge base for organizational growth. Interviews and discussions with the office personnel (both technicians and engineers) revealed that job responsibilities ranged from incoming inspection to component or system analysis to safety and risk. It was apparent that a broad base in applied probability and reliability along with tools for practical application was required...

Important psychosocial issues involving tension, cohesion, leader support, and displacement of negative emotions were evaluated in a 4 1/2-year study involving five U.S. and four Russian Shuttle/Mir space missions. Weekly mood and group climate questionnaires were completed by five U.S. astronauts, eight Russian cosmonauts, and 42 U.S. and 16 Russian mission control subjects. There were few findings that supported our hypothesized changes in tension, cohesion, and leader support in crew and ground subjects using various time models, although crewmembers reported decreasing leader support in the 2nd half of the missions, and astronauts showed some evidence of a novelty effect in the first few weeks. There was no evidence suggesting a 3rd quarter effect among crewmembers on any of the 21 subscales evaluated. In contrast, there was strong evidence to support the hypothesized displacement of tension and negative emotions from crewmembers to mission control personnel and from mission con...

As we approach the opportunity to send humans to Mars, we do so with an awareness of the risks and challenges crewed missions will face. Living and working in low-Earth orbit and visits to the moon five decades ago have provided a wealth of knowledge on the potential benefits and concerns for human planetary exploration. Technology and scientific investigation in a wide variety of disciplines has helped identify the challenges, risks, and enabling countermeasures for extending human presence in space. This manuscript reviews the current status of the challenges for transit to and from Mars plus considers the appropriate medical systems for productive stays on the Martian surface. These factors range from the optimization in crew selection to training, operational tempo, countermeasures, medical care systems, etc. Each of these are covered as a snapshot in time and will continuously evolve as technology in robotics, artificial intelligence, and risk aversion advances. It is impossible to include the detailed description of all the problems and human physiological decrements and medical needs. This document includes the main concepts for supporting safe and productive human missions to Mars and directions for the future analysis of medical support systems and provider competencies.

or the Keck telescope cannot make these kinds of observations due to their optical designs and narrow fields of view. The first generation of digital wide-field surveys from the ground (e.g. Sloan) have resulted in significant advances in astronomy and astrophysics, and their value is recognized by the additional decadal recommendation for continuing development of new ground-based telescopes designed for survey work (e.g. LSST). Bringing these wide-field design principles into space will revolutionize astronomical surveys in much the same way that the Hubble Space Telescope revolutionized imaging of individual astronomical objects and galaxies. The absence of atmospheric distortion and absorption, and the darkness of space enable space-based surveys to cover the near infrared band and go deeper, with more precision and accuracy, than can ever be possible from the ground. WFIRST will be the most sensitive near infrared space telescope designed for wide-field survey work, and will produce the most powerful and informative astronomical data set for probing the nature of dark energy, cataloguing the variety of exoplanet systems, and mapping the distribution of matter across cosmic time. The mission addresses the most fundamental issues in astrophysics utilizing existing, proven technologies, and could move into design and development immediately if a new start were to be approved. The WFIRST Science Definition Team (SDT) was formed to refine the science case for the mission, optimize the design and implementation scheme, and, with the WFIRST Project, develop a Design Reference Mission (DRM) to serve as the basis for further programmatic and technical review. This document is the interim report of the SDT and Project; accordingly, the interim DRM (IDRM) presented herein does not represent the final or only mission concept that could meet the requirements of the decadal recommendations. However, it does serve as an "existence proof" that an in-scope mission can be developed which successfully addresses all of the scientific objectives implicit in the decadal recommendation.

In this paper, in this edition of the Journal commemorating the life and work of David Wynn-Williams, we consider approaches to the astrobiological investigation of Mars. We provide a brief account of the scientific rationale behind the approach presented here. In particular, we outline the capabilities of the Raman spectrometer for the detection of biomarkers. David Wynn-Williams was an active champion of this instrument who was keen to field-qualify a version in Antarctica with a view to flying a Raman instrument onboard a Mars-bound space mission. We examine a scenario for the deployment of such an instrument in conjunction with other instrumentation and argue that subsurface deployment of scientific instruments is essential if we are to succeed in detecting any evidence that may exist for former life on Mars. We outline a mission scenario – Vanguard – which represents a novel but low-risk, low-cost approach to Mars exploration that was conceived and developed jointly by one of t...

The Italian participation to the consortium for the construction of a mid infrared (MIR) instrument for the Next Generation Space Telescope (NGST) has been defined during 2001. In this paper, a brief discussion about the key points of this participation is given.

Three Corner Sat (3CS) is a mission of 3 university nanosatellites scheduled for launch in late 2002. The 3CS mission will utilize significant autonomy to perform onboard science data validation and replanning. The 3CS mission will use onboard science data validation, responsive replanning, robust execution, and anomaly detection based on multiple models. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in space-borne science and space exploration that would be unreachable without this technology.

Complete planning and scheduling of all spacecraft operations is a challenging area with the remote agent experiment at Deep Space 1 being a pioneering system. Still the complete approach is rare in practice. For example, in the Mars Express (MEX) mission, planning and scheduling techniques are used to solve some subproblems namely scheduling command upload and data download. In this paper we describe an approach to generate a complete schedule of the spacecraft that includes planning and scheduling of science, command uplink, data downlink, maintenance, and pointing operations. The proposed solving approach was designed to plan operations on the Mars Express (MEX) mission and it was motivated by the MEX challenge at the Fourth International Competition on Knowledge Engineering for Planning and Scheduling. The method is based on incremental addition of operations to a partial schedule and modifying the time allocation of already scheduled operations to fit the newly added operation....

A three dimensional thermal analysis of a Lorentz force accelerator featuring an open heat pipe as a propellant feeding system is made in order to correct heat transfer problems that became apparent during attempts to operate the device. Specifically, the tem-perature profile along the multi-channel cathode of the thruster, which is also the open end of the heat pipe, was such that the cathode tip stayed at a tem-perature well below the vapor point of lithium thus causing lithium vapor to condense in the cathode. An empirically inspired solution was first implemented and consisted in outfitting the cathode assembly with a series of closed heat pipes that are heated form out-side the truster. However, the heat pipes failed to operate properly due to nearby thermal sinks that caused them to choke. The numerical thermal model showed what these sinks are and was instrumental in the implementation of a scheme that resulted in the successful operation of the thruster.

Autobiographies, memoirs, interviews, and oral histories of 72 spaceflight veterans were content analyzed to assess reported coping strategies in each phase of space missions (before, during, and after the flight). Comparisons were made on the basis of: Home space agency, gender, historical era of spaceflight, longest flight duration, and number of space missions completed. Trend analyses were used to track coping changes from the pre-flight period through the mission and after returning from space. Trained scorers used a standard coping strategy checklist to identify coping style whenever the material indicated that a problem had occurred and a solution was sought or applied. Differences across demographic and mission profile categories were found in materials referring to the three mission phases.

We apply a recently derived and explicitly closed form of the equations of chemically reacting flows under local thermodynamic equilibrium to investigate its appli- cability to hypersonic flows. This new model rigorously takes into account the eects of the separation of chemical elements due to the dierential diusion of species, known as elemental demixing. We study the particular case of

Tropospheric ozone estimates have been obtained using the residuals technique of Fishman et al. Based on existing TOMS and SBUV satellite data. However, the TOMS and SBUV data must be gathered from separate satellites and spectral channels for these sensors are not optimized for retrieval of tropospheric ozone. This study addresses both the combination of TOMS and SBUV capability into one sensor, as well as the selection of spectral channels.

We apply a recently derived and explicitly closed form of the equations of chemically reacting flows under local thermodynamic equilibrium to investigate its appli- cability to hypersonic flows. This new model rigorously takes into account the eects of the separation of chemical elements due to the dierential diusion of species, known as elemental demixing. We study the particular case of

Among the 17 volumes of results from the Hipparcos space mission, two are dedicated to variable stars. These two volumes arose from the work of two groups, one at the Geneva Observatory and one at RGO (Royal Greenwich Observatory), on the 13 million photometric measurements produced by the satellite for 118 204 stars. The analysis of photometric time series permitted us to identify several instrumental and mathematical problems: overestimation of the precision, offsets in the zero-points depending on the field of view, mispointing effects, image superpositions, trends in the magnitudes, binarity effects (spurious periods and amplitudes) and time-sampling effects. In this article we summarize some of the problems encountered by the Geneva group.

Constellation Pathfinder will demonstrate the feasibility of fabricating and launching three 1-kg satellites (nanosatellites) that are capable of collecting and returning quality scientific and engineering data for several months. The nanosatellite to be launched is based on one that has been under development for the past two years through the Magnetospheric Mapping Mission (MMM), a NASA New Mission Concept study. The study objective of MMM is to assess the feasibility of placing hundreds of nanosatellites equipped with magnetometers into orbits extending into the tail of the magnetosphere, thereby obtaining a much more detailed three-dimensional picture of dynamic phenomena in geospace than has been possible previously. The Constellation Pathfinder Mission (CPM) will take the first step toward such an ultimate implementation by launching similar satellites from the Shuttle. The hardware demonstration of building and flying such a satellite, or small suite of satellites, will provide a proof of principle of the satellite design that will be helpful in many scientific and strategic applications where a fleet of small satellites is required.

The great amount of data that will be produced during the imaging of Mercury by the stereo camera (STC) of the BepiColombo mission needs a compromise with the restrictions imposed by the band downlink that could
drastically reduce the duration and frequency of the observations.
The implementation of an on-board real time data compression strategy preserving as much information as possible is therefore mandatory.
The degradation that image compression might cause to the DTM accuracy is worth to be investigated. During the stereovalidation procedure of the innovative STC imaging system, several image pairs of an anorthosite sample and a modelled piece of concrete have been acquired under different illumination angles. This set of images has been used to test the effects of the compression algorithm (Langevin and Forni, 2000) on the accuracy of the DTM produced by dense image matching.
Different configurations taking in account at the same time both the illumination of the surface and the compression ratio, have been considered. The accuracy of the DTMs is evaluated by comparison with a high resolution laser-scan acquisition of the same targets. The error assessment includes also an analysis on the image plane indicating the influence of the compression procedure on the image measurements.

A short overview is given of the Solar Orbiter mission. First, the key scientific aims of the mission are briefly described. As the mission profile has consequences on the design of the payload instruments and their calibration, the mission design is described. Possible implications and problems for the cleanliness and the calibration stability of the instruments are outlined. Some solutions are discussed.

The Phoenix Lander, first of NASA's Mars Scout missions, arrived at the Red Planet on May 25, 2008. From the moment the lander separated from its interplanetary cruise stage shortly before entry, the spacecraft could no longer communicate directly with Earth, and was instead entirely dependent on UHF relay communications via an international network of orbiting Mars spacecraft, including NASA's 2001 Mars Odyssey (ODY) and Mars Reconnaissance Orbiter (MRO) spacecraft, as well as ESA's Mars Express (MEX) spacecraft. All three orbiters captured critical event telemetry and/or tracking data during Phoenix entry, descent and landing. During the Phoenix surface mission, ODY and MRO provided command and telemetry services, far surpassing the original data return requirements. The availability of MEX as a backup relay asset enhanced the robustness of the overall relay plan. In addition to telecommunications services, Doppler tracking observables acquired on the UHF link yielded a highly accurate position for the Phoenix landing site. 12 TABLE OF CONTENTS 1 1. INTRODUCTION .

The New Hard X-ray imaging and polarimetric Mission (NHXM) makes a synergic use of broad band spectroscopy (0.3-80 keV, 120 keV goal) and polarimetry (2-35 keV) as complementary diagnostics of the same astrophysical systems. Here we describe the polarimeters on-board NHXM. Two Gas Pixel Detectors, filled with different mixtures which are based on Helium and Argon, are placed alternatively in the focus of one out of the four telescopes. The instruments are sensitive in the 2-10 keV (LEP, Low Energy Detector) and 6-35 keV (MEP, Medium Energy Detector) energy bands. The performance is comparable, with a Minimum Detectable Polarization at 99% confidence level of 9.7% (LEP) and 13% (MEP) for a 1 mCrab source and an observation lasting 100 ks. Spectroscopy with moderate resolution (20% at 6 keV) and timing (8 ms) will be performed contemporaneously to polarimetry. Unique capabilities among next mission of X-ray polarimetry is the possibility to image the source with an angular resolution ...