We present the analysis of ≈100 molecular maps of the coma of comet 67P/Churyumov-Gerasimenko that were obtained with the MIRO submillimeter radiotelescope on board the Rosetta spacecraft. From the spectral line mapping of H O, H O, H O, CH3 OH, NH3 , and CO and some fixed nadir pointings, we retrieved the outgassing pattern and total production rates for these species. The analysis covers the period from July 2014, inbound to perihelion, to June 2016, outbound, and heliocentric distances r h = 1.24–3.65 AU. A steep evolution of the outgassing rates with heliocentric distance is observed, typically in , with significant differences between molecules (e.g. steeper variation for H2 O post-perihelion than for methanol). As a consequence, the abundances relative to water in the coma vary. The CH3 OH and CO abundances increase after perihelion, while the NH3 abundance peaks around perihelion and then decreases. Outgassing patterns have been modeled as 2D Gaussian jets. The width of these jets is maximum around the equinoxes when the bulk of the outgassing is located near the equator. From July 2014 to February 2015, the outgassing is mostly restricted to a narrower jet (full width at half-maximum ≈80°) originating from high northern latitudes, while around perihelion, most of the gaseous production comes from the southernmost regions ( − 80 ± 5° cometocentric latitude) and forms a 100°–130° (full width at half-maximum) wide fan. We find a peak production of water of 0.8 × 1028 molec. s−1 , 2.5 times lower than measured by the ROSINA experiment, and place an upper limit to a 50% additional production that could come from the sublimation of icy grains. We estimate the total loss of ices during this perihelion passage to be 4.18 ± 0.18 × 109 kg. We derive a dust-to-gas ratio in the lost material of 0.7–2.3 (including all sources of errors) based on the nucleus mass loss of 10.5 ± 3.4 × 109 kg estimated by the RSI experiment. We also obtain an estimate of the H O/H O ratio of 5.6 ± 0.8.

/pdf/long-term-monitoring-of-the-outgassing-and-composition-of-3rpb4pvihb.pdf

Long-term monitoring of the outgassing and composition of comet 67P/Churyumov-Gerasimenko with the Rosetta/MIRO instrument

Primitive body exploration missions such as potential Comet Surface Sample Return or Trojan Tour and Rendezvous would challenge traditional operations practices. Earth-based observations would provide only basic understanding before arrival and many science goals would be defined during the initial rendezvous. It could be necessary to revise trajectories and observation plans to quickly characterize the target for safe, effective observations. Detection of outgassing activity and monitoring of comet surface activity are even more time constrained, with events occurring faster than round-trip light time. "Agile science operations" address these challenges with contingency plans that recognize the intrinsic uncertainty in the operating environment and science objectives. Planning for multiple alternatives can significantly improve the time required to repair and validate spacecraft command sequences. When appropriate, time-critical decisions can be automated and shifted to the spacecraft for immediate access to instrument data. Mirrored planning systems on both sides of the light-time gap permit transfer of authority back and forth as needed. We survey relevant science objectives, identifying time bottlenecks and the techniques that could be used to speed missions' reaction to new science data. Finally, we discuss the results of a trade study simulating agile observations during flyby and comet rendezvous scenarios. These experiments quantify instrument coverage of key surface features as a function of planning turnaround time. Careful application of agile operations techniques can play a significant role in realizing the Decadal Survey plan for primitive body exploration.

https://arc.aiaa.org/doi/pdf/10.2514/6.2012-1273405

Agile science operations: A new approach for primitive bodies exploration

http://www.sp.ph.ic.ac.uk/~mgaland/Morse_etal_2012.pdf

The Rosetta campaign to detect an exosphere at Lutetia

This PhD thesis has been realized within the project of STC/SIMBIOSYS, the stereo channel composing the imaging system on board of the BepiColombo mission to Mercury and providing the global mapping in stereo mode of the Hermean surface. As the aim of this work is supporting the definition of the scientific requirements of STC, the impact craters have been recognized as the surface structure to be investigated, being the most important and common landform of any planetary body with a solid surface, but meanwhile far to be yet completely understood.
This thesis addresses to explore the importance of impact crater structure as a tool in investigating a variety of aspects of planetary bodies, whose remote sensing data is the only available information. Earth as well can take advantage from studying such a rarely occurring, complicated and highly dynamic process, as the combining effects of erosion, tectonics and volcanism can hide impact structures.
The first theme turns to impact craters not as an individual entity, but as a population of features on planetary surfaces, in particular Mercury. The cratering records, being the result of a long–repeated meteorite bombardment history, can be used to infer surface age after the application of a chronological model to statistical analysis. The data recently acquired by the MESSENGER mission during its three flybys with this planet were the starting point to study two new basins, i.e. Raditladi and Rachmaninoff. The MPF chronological model has been adopted to derive the crater retention age for these basins, whose impact events turned out to occur well after the LHB, posing some puzzles to the current impactor sources in the inner Solar System. In addition, Rachmaninoff interior plains could be emplaced in a very recent period (360 Ma ago), suggesting a long–lasting volcanism up to recent time, and hence a revision to our current knowledge on the thermal state of the planet is proposed
The second theme of my thesis addresses the investigation of the impact formation process. The current understanding of impact cratering as a whole has come from a suite of experimental, morphological, analytical and numerical studies. However, shocks codes represent one of the only feasible methods for studying impact craters, as they can simulate a large span of conditions beyond the reach of experiments, in addition to analyze the individual effect of any parameters acting during the impact event.
I have used iSALE shock code to simulate two craters, coming from a completely different environment, the Earth and one asteroid, recently observed by a space mission. In the first case, the knowledge of the surrounding area where the structure is located allowed to study in detail the impact crater collapse mechanism that origins a large crater. On the other hand, the good relatively knowledge of the formation of a simple crater allowed to investigate the composition and the structure of the asteroid. In both cases, the numerical modelling of the impact process has demonstrated to be a powerful tool to deepen our comprehension on the Solar System.

The importance of being a crater:a tool in planetary surface analysis and datation

The capabilities of a single fluid gasdynamic model of so- lar wind-comet exosphere interaction, presented in the accompanying (Keremidarska et al.) (23), are discussed from the point of view of its potential implementation in interpreting data, expected to be obtained by ROSETTA mission instruments in plasma environments of the comet 67P/Churyumov-Gerasimenko. As an exapmle, some model's predic- tions of the structure and parameters' distribution in the inner coma of P/Halley are presented and compared with Giotto measurements. Spe- cial attention is paid to a possible non-traditional interpretation of the magnetic cavity boundasry, registered by Giotto magnetometer. Possible model's applications are discussed for each of the main expected stages in the evolution of the comet 76P/CG environments during ROSETTA

Solar wind-comet exosphere interaction. 2. could the single-fluid gas-dynamic model be applicable to the rosetta mission ∗

ESA’s Rosetta mission was launched in March 2004 and is on its way to comet 67P/Churyumov-Gerasimenko, where it is scheduled to arrive in summer 2014. It comprises a payload of 12 scientific instruments and a Lander. All instruments are provided by Principal Investigators, which are responsible for their operations. As for most ESA science missions, the ground segment of the mission consists of a Mission Operations Centre (MOC) and a Science Operations Centre (SOC). While the MOC is responsible for all spacecraft-related aspects and the final uplink of all command timelines to the spacecraft, the scientific operations of the instruments and the collection of the data and ingestion into the Planetary Science Archive are coordinated by the SOC. This paper focuses on the tasks of the SOC and in particular on the methodology and constraints to convert the scientific goals of the Rosetta mission to operational timelines.

/pdf/scientific-planning-and-commanding-of-the-rosetta-payload-4k70mof1av.pdf

Scientific Planning and Commanding of the Rosetta Payload

Managing Risk to Ensure a Successful Cassini/Huygens Saturn Orbit Insertion (SOI)

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Scientific Planning and Commanding of the Rosetta Payload

Managing Risk to Ensure a Successful Cassini/Huygens Saturn Orbit Insertion (SOI)