Cryogenic system design for a hydrogen sorption cooler
This paper presents the cryogenic design of Hydrogen Sorption Cooler, part of cryogenic chain in the Planck Mission (ESA).
cryocooler↗
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Results for “ESA”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Rubidium Ultra-Stable Oscillators at Titan: The Huygens Doppler Wind Experiment
The Doppler Wind Experiment (DWE) is one of six investigations to be performed during the Titan atmospheric descent of the ESA Huygens Probe. The primary scientific objective is to measure the direction and strength of Titan's Zonal winds with an acuracy better than 1 m s-1.
Rubidium↗
Mars Sample Return Conceptual Mission Overview
This talk will provide an overview of an overall Mars Sample Return campaign architecture, and the current concepts and options for the architecture and design of a Mars Sample Retrieval Lander (called Sample Retrieval Lander, SRL). The overall SRL mission concept and key mission objectives will be described, including the mission’s concept of operations and a notional timeline from launch to entry, through surface operations, to delivery of the samples to Mars orbit. The overall lander vehicle concept will be described, including current options being evaluated. Key lander element options will be discussed, including a Mars Ascent Vehicle (MAV), Fetch Rover, Orbiting Sample container (OS), and tube transfer robotics systems. Details of the notional Fetch Rover functions, constraints and operations will be discussed. Specific challenges and approaches for addressing those challenges will be discussed, including key technical margins and planetary protection. Major trade studies and implementation approaches and a proposed schedule will also be discussed. The information provided about possible Mars sample return architectures and concepts is for planning and discussion purposes only. NASA and ESA have made no official decisions to implement Mars Sample Return.
Beyer, Friederike↗
Deep-Space Navigation Using Optical Communications Systems
Optical communication links using lasers can potentially deliver data rates much higher than those possible using radio frequencies. If optical communications equipment is going to be carried by future deep-space missions, this equipment, with some adaptations, could also be used to perform tracking for trajectory determination. A number of experiments have been performed in Earth orbit and in lunar orbit using optical data links, while other missions have demonstrated optical links over interplanetary distances. Laser ranging using corner cube retroreflectors is a well-established technique that has been used for orbit determination of Earth orbiting spacecraft, for geodesy, and for lunar research, achieving centimeter-level precisions, but it is not a practical method for deep-space distances. There are two main optical tracking types that are being considered for deep-space navigation. The first is optical astrometry of spacecraft: a telescope on the ground images the laser beam coming from a spacecraft against the star background, determining its plane-of-sky position as seen from the observatory. This type will greatly benefit from the release of the high-accuracy star catalog produced by ESA’s Gaia mission, allowing for the generation of plane-of-sky measurements with an accuracy similar to that obtained today using VLBI tracking techniques. The second is optical ranging using active optical systems at both ends of the link, requiring a more careful design of the spacecraft optical communications system. One of the advantages of using optical frequencies is that they are not affected by charged particles in the signal path the way that radio frequencies are, eliminating solar plasma and ionospheric effects from the light-time calculation and the corresponding noise. On the other hand, clouds would preclude any type of optical communication, and daytime light scattering precludes astrometric measurements. This paper presents our analysis so far of the performance that could be achieved using optical data types in a number of deep-space scenarios. One of the questions that we are trying to answer is whether spacecraft equipped with optical communications terminals would also need to carry radio-frequency equipment for navigational purposes. We also want to understand how accurately we will be able to navigate spacecraft in different mission types and phases, and what would be the constraints, advantages, and disadvantages of using optical communications systems for deep-space navigation.
Karimi, Reza↗
Cassini Power During the 20 Year Mission and Until the Final Plunge into Saturn
The NASA-ESA Cassini mission ended on September 15, 2017, after almost 20 years of operations. Electrical power telemetry data is presented for the entire mission from launch and End Of Mission (EOM). The Cassini spacecraft was powered by three Radioisotope Thermoelectric Generators (RTGs) connected in parallel. These three RTGs generated 882.1 W at the beginning of the mission. At EOM, the power level was 600.3 W. The electrical output of Cassini’s power subsystem decayed consistently, as predicted, during the entire mission between October 1997 and September 2017. Further, no heating of the RTGs was reported in telemetry during the last minutes of the mission, nor was there any variance apparent in the final output of the three RTGs that is attributable to the final plunge into Saturn.
Burk, Thomas A.↗
Practical Orbit Determination for Aerobraking with Accumulated Accelerometer Data
Navigation during aerobraking missions has historically relied solely on radiometric Doppler data. Accelerometer data, available on all modern spacecraft, has the potential to supplement Doppler data, increasing operational tempos, filling tracking data gaps, and improving the accuracy of orbit determination solutions. However, integration of Doppler and accelerometer data into the batch filter solutions used for operational navigation has proven to be practically challenging, due to the narrow region of adequate linear approximation for acceleration incurred by drag. This work proposes to use the accumulated velocity changes derived from these values as a more compatible data type. Demonstrations of results focus on NASA’s Maven and ESA’s TGO mission, and how this technique can be used to improve operations for the upcoming Maven aerobraking phase with reduced tracking data and lighter staffing requirements.
Young, Brian↗
Spacecraft Micro-Vibration: A Survey of Problems, Experiences, Potential Solutions, and Some Lessons Learned
Predicting, managing, controlling, and testing spacecraft micro-vibrations due to on-board internal disturbance sources is a formidable multi-disciplinary systems engineering challenge, especially for those observatories hosting extremely sensitive optical sensor payloads with stringent requirements on allowable Line-of-Sight (LOS) jitter. In this paper some specific spacecraft micro-vibration engineering challenges will be introduced and described. Technical background context is provided with the inclusion of several illustrative examples of NASA and ESA missions (both past and present) where dynamic interactions have to be addressed and which have demanding payload instrument LOS jitter requirements. A general modeling, analysis, simulation, and test approach to address and solve the overall problem of spacecraft micro-vibrations is outlined. Recommended rules of thumb are presented to provide guidance for analysts on where to initiate and how to approach a new spacecraft micro-vibration design problem. A set of experience based spacecraft micro-vibration lessons learned are also presented in the hope they can be leveraged on new system development projects to help overcome unfamiliarity with previously identified micro-vibration technical pitfalls and challenges.
Alvarez-Salazar, Oscar S.↗
Design Principles for Smallsat SARs
Synthetic Aperture Radar (SAR) is by now a mature remote sensing technique to obtain spatially-resolved radar measurements of terrain. Currently, SAR image data are readily available from an ever-expanding multitude of SAR satellites in Earth orbit. Many spaceborne SAR systems currently in use or planned for the near-term are multifunctional: their designs tend to maximize the menu of image modes available to the end user. They also follow fairly conventional design principles, laid down decades ago, that lead almost inevitably to large antennas and even larger spacecraft. This raises the question: how does one go about designing a SAR system that fits in a Smallsat (<200 kg) form factor? The design principles for Smallsat SARs outlined in this paper have been developed over a twenty-year period in architecting Earth-orbiting SARs such as NASA/JPL’s NISAR and ESA’s Biomass mission, as well as planetary SAR mission concepts. Example mission concepts following this approach will be presented at the end of the paper. These include an S-Band Smallsat geodetic constellation to measure surface deformation, as called for by the 2018 National Academy Decadal Survey for Earth Observation from Space. Another example is a Ka-band cubesat-sized system designed to detect changes on Earth’s surface.
Freeman, Anthony↗
The Mars Reconnaissance Orbiter Mission: 2018 Status
The Mars Reconnaissance Orbiter (MRO) continues its dual-mode mission of scientific exploration and programmatic support. Now in its 13th year of flight (and its 12th year in its low-altitude, sun-synchronous orbit around Mars), the spacecraft continues in its normal flight mode and its science instruments continue to acquire a treasure trove of data which is being used to study the Martian environment (surface, sub-surface, and atmosphere). To date (July 2018), more than 333 TB of scientific data have been returned to Earth. Building onto the 2017 IAC paper: “The Mars Reconnaissance Orbiter Mission: Continuing a Record of Exploration from Mars Orbit,” [1] this paper provides a 2018 status update on the MRO Mission. A signature event since the 2017 writing is the onset and evolution of a planet-encircling dust event (PEDE), the first such event since 2007. Additional recent science highlights for MRO include the discovery of mid-latitude ice cliffs, polar cap characterization, daily global mapping of the 2018 PEDE dust activity and the atmospheric thermal response, further characterization of the tantalizing recurring slope lineae (RSL), and continued detection of surface changes. Programmatically, UHF relay support for the Mars Science Laboratory (MSL) rover Curiosity and the Mars Exploration Rover (MER) rover Opportunity continues at a pace that provides the engineers and scientists operating those surface vehicles timely information to support their mission planning and science analysis. Most of the landing site characterization requests for the NASA Mars 2020 rover and the ESA ExoMars Rover/Surface Platform (RSP) missions have been completed, with final acquisitions delayed due to the obscuring dust haze from the current PEDE. In parallel, the flight team has faced new engineering challenges as the spacecraft has aged. The team has developed and is implementing actions that are aimed at stretching spacecraft battery life. A new all-stellar capability using the spacecraft’s star trackers now allows for normal spacecraft operations without IMUs. In addition to its current relay duties, MRO will be synchronized to provide critical communications support for the InSight Entry, Descent, and Landing (EDL) event on November 26, 2018, and will be readied to support InSight’s critical commissioning phase with UHF relay support and environmental characterization. A new split-pass relay capability has been developed which will allow MRO to relay with two surface vehicles in “close proximity” on the same overflight, i.e. the InSight lander and the Curiosity rover. Extended for another year of operations by NASA, this paper will highlight recent scientific progress and describe actions that will extend MRO’s life well into the 2020’s as a key element of the Mars Exploration Program.
Zurek, Richard W.↗
Mars Sample Return Conceptual Mission Overview
This talk will provide an overview of an overall Mars Sample Return campaign architecture, and the current concepts and options for the architecture and design of a Mars Sample Retrieval Lander (called Sample Retrieval Lander, SRL). The overall SRL mission concept and key mission objectives will be described, including the mission’s concept of operations and a notional timeline from launch to entry, through surface operations, to delivery of the samples to Mars orbit. The overall lander vehicle concept will be described, including current options being evaluated. Key lander element options will be discussed, including a Mars Ascent Vehicle (MAV), Fetch Rover, Orbiting Sample container (OS), and tube transfer robotics systems. Details of the notional Fetch Rover functions, constraints and operations will be discussed. Specific challenges and approaches for addressing those challenges will be discussed, including key technical margins and planetary protection. Major trade studies and implementation approaches and a proposed schedule will also be discussed. The information provided about possible Mars sample return architectures and concepts is for planning and discussion purposes only. NASA and ESA have made no official decisions to implement Mars Sample Return.
Beyer, Friederike↗
Leveraging Mars aerobraking experience for the Venus environment
Aerobraking was first demonstrated at Venus during the Magellan extended mission in 1993 and on every Mars orbiter since, from the Mars Global Surveyor (MGS) in 1997 to ESA’s Trace Gas Orbiter (TGO) in 2017. This paper illustrates the differences between aerobraking at Venus and at Mars from both the astrodynamics and thermal perspectives. It shows how the periapsis velocity hammers the drag versus aerothermal heating relationship with comparable aerothermal heating limits and initial conditions at Mars and at Venus. Even though there are noticeable differences in the aerobraking environment between these two planets, the Mars heritage operations, processes, tactics, and strategy remain the same while addressing these differences in mission design and environment. Additionally, the spacecraft design requirements, capabilities, and thermal guards are retained across projects and planets. The operations processes and procedures developed over the 20 years of Mars experience can be equally applied back to the birthplace of aerobraking: Venus.
Wallace, Mark S.↗
Radio science at Jupiter: past investigations, current results, and future prospects
The latest mission to Jupiter, Juno, includes the most advanced radio science instrumentation to date. With Juno’s unique polar orbit and dual frequency radio links, it is able to probe the planet’s deep interior structure and zonal wind profile with measurements of the gravitational field and probe the electron densities in the Io plasma torus, a doughnut-shaped ring around Jupiter charged with particles emitted by the volcanic activity on Io. Upcoming missions, such as the planned NASA’s Europa Clipper multiple flyby mission in 2022, potential follow-on Europa Lander, and the ESA’s Jupiter Icy Moons Explorer mission in 2022, may make further strides in the study of the planet and its moons utilizing radio science.
Oudrhiri, Kamal↗
Potential campaign architectures and mission design challenges for near-term international Mars Sample Return mission concepts
Mars Sample Return (MSR) continues to be a high priority in the planetary science community and a decades-long goal of international planetary exploration programs. Options for architectures and mission concepts are currently under study by NASA and ESA to find potential partnership opportunities to achieve MSR in the 2020s. The major elements of a potential MSR campaign have significant architectural flexibility and mission launch, arrival, and return options. The decision criteria often depend on mission design and functional allocations across many elements. This paper outlines the reference architecture and key trades among the campaign elements.
Olikara, Zubin↗
Aerobracking the ExoMars TGO: the JPL Navigation Experience
In October 2016, ESA’s Trace Gas Orbiter entered into orbit around Mars. The transfer from its initial 24-hour elliptical orbit into the final 2-hour science orbit was helped by means of 952 aerobraking passes between March 2017 and February 2018. For this first aerobraking operation by European Space Operations Centre (ESOC), a dedicated partnership was organized between ESOC and NASA’s Jet Propulsion Laboratory (JPL) to allow for JPL navigation team’s support during the TGO aerobraking operations. The Mission Design and Navigation section at JPL supported the mission by providing consulting in aerobraking navigation operations and independent orbit determination solutions during TGO’s aerobraking. This paper discusses the JPL Navigation team’s experience, challenges faced, and lessons learned during TGO’s aerobraking at Mars. Topics include the collaboration between the two navigation teams, configuration of orbit determination for aero drag passes, arrangement of automated orbit determination, and reporting processes.
Young, Brian↗
Mission analysis for a potential Mars Sample Return campaign in the 2020's
The Mars 2020 mission, currently under development by NASA, plans to acquire and cache carefully-selected rock and regolith samples from the surface of Mars for potential future return. NASA and ESA are jointly studying options for returning those samples to Earth with missions launching in the 2020s. This paper demonstrates a method for modeling the various campaign elements, synthesizing coordinated campaign timelines, and assuring trajectory feasibility in the presence of many constraints, and finally optimizing towards mission success. Options for complete sample return campaigns in multiple launch and arrival opportunities are explored and compared.
Huesing, Jakob↗
SMAP science recovery efforts
The Soil Moisture Active Passive (SMAP) spacecraft launched in January 2015, with a mission to produce global soil moisture maps every 1.5 days using a combination of active (radar) and passive (radiometer) L-band measurements. In July 2015, after 2.5 months in operation, the radar failed and was not able to transmit. While the radiometer was still producing excellent science measurements, the need to recover key active-passive soil moisture requirements was paramount. To that end, the science team found that the European Space Agency (ESA) had recently launched a C-band SAR spacecraft called Sentinel-1A (launched April 2014) in a similar orbit, which was seen as a potential replacement to the “active” part of the SMAP measurements. An analysis was performed to see what the resulting spatial and temporal coverage could be. The promising results of that coupled with the ramp up in global coverage from Sentinel-1A and 1B (launched April 2016) allowed SMAP to create a new joint science data product that strives to meet the original mission objectives. The joint product is now part of the routine release of SMAP data to the science community as of June 2018.
Ballard, Christopher G.↗
Investigating Mercury's Environment with the Two-Spacecraft BepiColombo Mission
The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well as their interactions with the solar wind, radiation, and interplanetary dust. Many scientific instruments onboard the two spacecraft will be completely, or partially devoted to study the near-space environment of Mercury as well as the complex processes that govern it. Many issues remain unsolved even after the MES-SENGER mission that ended in 2015. The specific orbits of the two spacecraft, MPO and Mio, and the comprehensive scientific payload allow a wider range of scientific questions to be addressed than those that could be achieved by the individual instruments acting alone, or by previous missions. These joint observations are of key importance because many phenomena in Mercury’s environment are highly temporally and spatially variable. Examples of possible coordinated observations are described in this article, analysing the required geometrical conditions, pointing, resolutions and operation timing of different BepiColombo instruments sensors.
Mercury's environment↗
Performance of a broad-band, high-resolution, transition-edge sensor spectrometer for X-ray astrophysics
Future X-ray astrophysics experiments require multiplexed readout of high fill-factor, kilo-pixel arrays of transition-edge sensors (TESs), with very high spectral resolution over a broad range of energies. In this paper we report on a prototype kilo-pixel array of Mo/Au TESs readout with 8-column by 32-row time-division multiplexing (TDM). This system is being used to demonstrate the critical detector and readout technology for ESA’s Athena X-IFU, and when complete will be used in laboratory astrophysics experiments. Our array and TDM readout have demonstrated a combined full-width-at-half-maximum energy resolution, including >200 pixels, of:1.95 eV for Ti-Ka(4.5 keV), 1.97eV for Mn-Ka(5.9 keV), 2.16 eV for Co-Kα(6.9 keV),2.33 eV for Cu-Kα(8 keV), 3.26 eV for Br-Kα(11.9 keV). The 1 sigma statistical errorsare£0.01 eV for all spectra. These results meet the broad-band resolution requirements for X-IFU with margin.
S J Smith↗