SBN Comet Data Review 15 October 2004 Attending: Stephanie McLaughlin Tony Farnham Ludmilla Kolokolova Beatrice Mueller David Rabinowitz Chuck Acton Marina Fomenkov Anita Cochran Tyler Brown Anne Raugh Mike A'Hearn J-C Liou (arrived 9:05a) General Notes ------------- - Dave R. notes that the CIDA data had nearly all the necessary spacecraft orientation information included in the data file. This was generally agreed to be useful, and should be done in future mission data sets where feasible. - We and CN still need a simple entry point where users can type in a DATA_SET_ID they've found somewhere and get immediately to information about the data set. - When SPICE is used to generate geometry values in labels, the DATA_SET_ID should be referenced in the data label and the specific kernels used should be identified by filename. In cases where non-archived kernels were used, the kernel files themselves should be included in the data set archive. Stardust General ---------------- - In the "onlabels.txt" file, the description of the spacecraft clock count format is slightly different from that actually in these data files. SDCIDA_0001 ----------- Liens: - dataset.cat refers to a document containing thumbnail images which does not exist. It should be created and supplied. - The DATA_SET_DESC needs to be more explicit about the amount and type of science and non-science results included in the data set, and how to quickly distinguish them (like, for example, consulting the index.tab file). - The "Data Calibration" subheading in the data set description refers to a in-flight calibration example which doesn't exist. At the very least there should be a reference to a paper that shows laboratory calibration, when one is available. The processed described as "calibration" here is actually data reduction. That terminology should be changed. - There is no explanation of the target signal meaning, significance, etc. - The instrument description, especially with respect to the channels, is inadequate. For example, it is not at all clear that the word "redundant" is being used correctly. Also there is no explanation for the pattern of zero-valued columns that appears in encounter data but not cruise data. - The calexmpl.old file should be deleted (it's not even labeled). - The calexmpl.pdf file contains numerous ambiguities, incomplete descriptions, etc. A better description of the channels and what is needed for each is essential. Proof-editing to make sure that values in tables and equations are properly correlated, and references to the appropriate published papers would also help. - Documentation is needed for all known and suspected malfunctions, glitches, resets, idiosynchracies, etc. of the instrument. If there were no such failures, the missing data (i.e., the zero-valued columns) must be explained. - An example of a reduction of real data (in addition to the laboratory example) is needed. - Split the known non-science data into a separate directory from the known and possible science data. These data are rejected for archiving because of the documentation deficiencies. It will remain in the IN_PREPARATION queue pending new documentation. SBN will continue to attempt to coax this documentation out of the PI, et al. SDDFMI_0001 ----------- Liens: - The Small Sensor reported no impacts at the m4 threshold, but there is no mention of this in the documentation. The lack of results should be noted and explained. - In the Acoustic Sensor values, particularly the high & low bumpers, the values around close approach do not seem reasonable - the "cumulative count" increases and decreases a number of times, but there is no documented instrument problem or rollover that might explain this. An explanation is needed. - Column heading definitions do not contain units. The appropriate units (or modified column headings) should be added. - In the .fmt file, column 9, et al. descriptions should say that it is a low/high mass threshold, not just a low/high threshold. - .fmt file: Column 12 description says "low" where it should be "high" and "sensor 1" where it should be "sensor 2". - fmt file: Columns 13-16, description should be reworded to refer to the lowest, second lowest, etc. - omitting the "large sensor threshold" terminology which is confusing. Propagate elsewhere in the file as appropriate. - In tables 1 & 4 of dfmical.pdf, the "byte" references don't actually refer to the data file presented here, but rather the telemetry stream as it came down. This should be made clear. - The times recorded in the data file need some additional documentation. Specifically, we need to know the relationship between the reported time and the point of measurement. - Provide some additional explanation and guidance on how and when to apply the two different calibration constants. Add a discussion of the uncertainty in the calibration. - If the dfmical.pdf file is re-created, place the figures in-line if possible. SDNC_0003 --------- Notes: Reviewers had problem accessing these images. The attached PDS labels are not generally supported and the principal reviewer encountered serious problems getting NASAView to run on her system. In NASAView - what is the difference between "Stretch Image" and "Stretch Display"? Liens: - Mission.cat needs updating for activities since the file was originally written. (Tony has a list of specific items to be updated.) - The instrument catalog file refers to calibration checks "to be done" between Annefrank and Wild 2. This information should be updated for whatever happened with these checks. - The DATA_SET_DESC should point to the piimglog.pdf file for the image log table and the index.tab file. - In the index table, the column descriptions for some of the more obscure values (like reticle point descriptions, e.g.) should contain a bit more information, so that the average science user does not need to refer back to, e.g., "onlabels.txt" constantly. - Actually, "inlabels.txt" does not provide a better explanation in this case. - If possible, please insert column headings at the beginning of each page of the table (or periodically throughout the table) in the piimglog.pdf file. - Some images show stripes (e.g., n2091we02.img) that are not noted or explained in the documentation. The cause of these bars needs to be tracked down and documented, and we need to search the data set and identify all images affected, if possible. Boris Semenov notes these lines are noise, and are present to a greater or lesser degree in all images. - In the piimglog.pdf file, the majority of image file names end in ".01", whereas the data file names in the data directory end in "02". Boris S. (via telecon) notes that 01 vs 02 indicates versions of the label for the image. The content should be the same. This difference should be explained. - The focal length of the camera is given incorrectly, based on the pixel scales given in the labels. - A single file tabulating the pixel scale values throughout the dataset should be added if possible. - If it is possible to put pixel scale in the piimglog.pdf, please do. - The index.tab file contains constant-valued columns that make the file difficult to use. Omit these columns. - The image file labels need to include LINE_DISPLAY_DIRECTION, SAMPLE_DISPLAY_DIRECTION, and AXIS_ORDER_TYPE. - The ASCII tables in the document directory need to be sorted out and the relevant table(s) placed in a calibration directory as a properly formatted TABLE. - If possible, modify the calrpt.pdf file to add a page of caveats regarding the limited usefulness of the ground calibration. SDDS_0001 --------- J-C. Liou notes that these data are not really of scientific value in and of themselves, but rather are useful in interpreting other Startdust data sets. Liens: - The data cannot be interpreted without additional information. For example, the inst.cat file contains a filler paragraph under the "Location" subheading, and there are numerous [TBD] fields. Boris has some of this information, but not all of it (detailed AC description, for example). - The plots of the attitude rate columns look odd. Is there an explanation for the pathology of these variables? The signal seems to oscillate by the size of the quoted delta-value in the data set description. And what is the significance of the spikes that appear in the plots? - Add the following documentation: o Explanation of what happens to the angular momentum values when the spacecraft is hit by a particle o An explanation for the pathology of the angular momentum plots o An explanation for the repeated values in the last three columns in the telemetry file during the high data rate periods near encounter o A note that there are no cruise data, and why o Time of closest approach - Boris has offered to provide a description of how the two files comprising the dataset would be used together. This would be very helpful. - Add error bars, or a note about precision, for the velocity measurements if possible. - Please include a table of relevant spacecraft parameters for the convenience of the users. - Note in the DATA_SET catalog file that this data set is intended to support the analysis of other Stardust data sets. Ideally, the other Stardust data set descriptions should also reference this data set. WILD2_SHAPE ----------- Liens: - Change the name of this data set to something like "Tri-axial Ellipsoidal Fit". - In the documentation directory, some additional information is needed about the PNG figure (what the colored axes mean, what the orientation is, etc.). - Add a geometry diagram. Mike knows which figure to add, and Chuck says he knows what figure he's talking about. - Where the data set description references a data set, provide a brief description of what the referenced data set contains and where to go to find that data. SDSP_1000 --------- Notes: - Stephanie will submit a formal request to the NAIF node to add some additional keywords to one of the SPICE kernel files. Details are in Stephanie's notes. Liens: - Stef noticed some small (0.01%) variation in one of the parameters she calculated and what appears in the labels for the NAVCAM data. Boris notes this is probably a difference in the type of light travel time corrections applied. They will double-check this offline. - We (SBN, NAIF and CN) need to decide whether this should be V2.0 or remain V1.0. The data set catalog file should document the completeness (in terms of expected additional data deliveries or future enhancements) of the data set. - The data set catalog file should document the subtleties of using spacecraft times vs. UTC in certain circumstances (see Stephanie's notes). Add a document giving an example if possible. - When the appropriate information becomes available, NAIF will "be happy" to make a PCK kernel. SBN will monitor the availability of shape models and request the PCK kernel when the models are published. - The IK file text includes some question marks that seem to be placeholders The missing data should be supplied. - In the index.lbl file, it would be nice to provide a brief explanation of the different precisions in the UTC field. Wrap-Up ======= Beatrice notes that ground-based observers should be encouraged to and supported in submitting their datasets. OLAF is part of this, but we also need to provide some simple, clear explanations of acceptable formats, what should be included in the archive. J-C. notes that having a data producer representative present is VERY helpful when it comes to finding immediate answers to questions that arise during discussion. Ludmilla suggests we should include a list of known potential data access/visualization problems (like using NASAView vs. PDSread, and the Internet Explorer issue with displaying .cat files) in the letter we send to reviewers. We need to make sure that either OLAF users are better educated about how to answer certain questions (like TARGET_NAME), or make sure that the output from OLAF is reviewed by a knowledgeable PDS person and corrected prior to posting to the reviewers. ========================================================================