Scientific Planning and Commanding of the Rosetta Payload

Koschny, D.; Dhiri, V.; Wirth, K.; Zender, Joe; Solaz, R.; Hoofs, Raymond; Laureijs, R. J.; Ho, Tra‐Mi; Davidsson, B.; Schwehm, G.

doi:10.1007/s11214-006-9129-3

Cited by 10 publications

(6 citation statements)

References 2 publications

(1 reference statement)

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“…The MIRO instrument operated as a single-beam submillimeter radiotelescope mounted rigidly on the Rosetta spacecraft. The pointing axis was aligned with the +Z axis of the spacecraft, as were most of the other remote-sensing instruments (Koschny et al 2007). During the entire Rosetta observation period, MIRO operated continuously, mostly in "CTS/dual-continuum" mode (Gulkis et al 2015).…”

Section: Mapping Of Submillimeter Linesmentioning

confidence: 99%

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

Biver¹,

Bockelée‐Morvan²,

Hofstadter³

et al. 2019

A&A

110

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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 H216O, H218O, H217O, CH3OH, 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 rh = 1.24–3.65 AU. A steep evolution of the outgassing rates with heliocentric distance is observed, typically in rh−16, with significant differences between molecules (e.g. steeper variation for H2O post-perihelion than for methanol). As a consequence, the abundances relative to water in the coma vary. The CH3OH 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 H218O/H217O ratio of 5.6 ± 0.8.

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Section: Mapping Of Submillimeter Linesmentioning

confidence: 99%

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

Biver¹,

Bockelée‐Morvan²,

Hofstadter³

et al. 2019

A&A

110

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“…by painting the spacecraft black so that sticking dust will not significantly change the thermal properties of the spacecraft, and by employing movable shutters in front of sensitive surfaces such as cameras. Nevertheless, in the vicinity of the comet, spacecraft operations will keep exposure to dust to a minimum [79]. In order to fulfil the dust collection requirements of the COSIMA and MIDAS instruments the spacecraft occasionally will have to pass through regions of high dust density.…”

Section: Dust Collection Along Sample Spacecraft Trajectoriesmentioning

confidence: 99%

Dust Environment Modelling of Comet 67P/Churyumov-Gerasimenko

Agarwal¹,

Müller

Grün

2007

Space Sci Rev

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Dust is an important constituent of cometary emission; its analysis is one of the major objectives of ESA's Rosetta mission to comet 67P/Churyumov-Gerasimenko (C-G). Several instruments aboard Rosetta are dedicated to studying various aspects of dust in the cometary coma, all of which require a certain level of exposure to dust to achieve their goals. At the same time, impacts of dust particles can constitute a hazard to the spacecraft. To conciliate the demands of dust collection instruments and spacecraft safety, it is desirable to assess the dust environment in the coma even before the arrival of Rosetta. We describe the present status of modelling the dust coma of 67P/C-G and predict the speed and flux of dust in the coma, the dust fluence on a spacecraft along sample trajectories, and the radiation environment in the coma. The model will need to be refined when more details of the coma are revealed by observations. An overview of astronomical observations of 67P/C-G is given, because model parameters are derived from this data if possible. For quantities not yet measured for 67P/C-G, we use values obtained for other comets, e.g. concerning the optical and compositional properties of the dust grains. One of the most important and most controversial parameters is the dust mass distribution. We summarise the mass distribution functions derived from the in-situ measurements at comet 1P/Halley in 1986. For 67P/C-G, constraining the mass distribution is currently only possible by the analysis of astronomical images. We find that both the dust mass distribution and the time dependence of the dust production rate of 67P/C-G are those of a fairly typical comet.

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“…2 It is believed that there will be approximately three to five trajectory updates prior to delivery of the Philae spacecraft. In this short time, the science teams must identify the most interesting landing site and adequately characterize its safety (considering factors like roughness, fissures, or active outburst regions).…”

Section: Case Study: Landing Site Characterizationmentioning

confidence: 99%

“…We envision operators identify a candidate site in context images and then wish to follow up with a targeted measurement during the same trajectory. Our computation of reaction time assumes a reference Rosetta planning scheme detailed in Koschny et al 2 A one-week downlink interval determines the length of the runout/downlink queue. We integrate over all possible time gaps between the initial imaging of the target and the next downlink, assuming discovery is equiprobable at any time during the one week interval.…”

Section: Case Study: Landing Site Characterizationmentioning

confidence: 99%

“…These missions would have little information about the targets before arrival, so key science goals would be defined in concert with initial data collection. Such missions would require a period of characterization in the target environment to understand how best to operate a mission effectively from both a science and an engineering perspective 2,3 . Mission success would require operators to quickly climb this learning curve and revise observation plans.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Agile science operations: a new approach for primitive bodies exploration

Thompson¹,

Castillo‐Rogez²,

Chien³

et al. 2012

SpaceOps 2012 Conference

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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.

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Scientific Planning and Commanding of the Rosetta Payload

Cited by 10 publications

References 2 publications

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

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

Dust Environment Modelling of Comet 67P/Churyumov-Gerasimenko

Agile science operations: a new approach for primitive bodies exploration

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