PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM ^TEXT = "AAREADME.TXT" OBJECT = TEXT PUBLICATION_DATE = 2017-08-07 NOTE = "AAREADME.TXT describes this volume." END_OBJECT = TEXT END Volume DWNC3GRD_1A Dawn GRaND Raw Level-1A Ceres Extended GRaND Archive 2016-11-02 - 2017-02-22 ============================================================================== Brief Volume Description ============================================================================== This volume contains data from the Dawn GRaND raw level-1A (EDR) Ceres extended mission data set covering the Transfer to GRAND (CTG) and Ceres Extended GRAND (CXG) mission phases. The volume includes a time-ordered collection of gamma ray and neutron counting data and histograms acquired by the GRaND instrument. The Ceres data from earlier Ceres and later phases are archived on separate volumes (DWNCAGRD_1A, DWNCLGRD_1A, DWNC1GRD_1A, DWNC2GRD_1A,,DWNC4GRD_1A,). This completes the Ceres data set for the prime mission and Ceres extended mission. Descriptions of how the GRaND data are organized can be found in the Software Interface Specification (SIS) and Data Processing documents (both in the DOCUMENT directory) and in Prettyman et al. (2011) Space Science Reviews, Vol. 163(1-4), pp. 371-459, http://dx.doi.org/10.1007/s11214-011-9862-0 NOTE: Reading the Science Plan (DOCUMENT/SCIENCE_PLAN/DAWN_SCIPLAN_V5_4.PDF) is critical to the understanding of Dawn observations and science objectives. Other critical documentation in the DOCUMENT directory include the volume SIS and calibration procedure. The Experiment Data Record (EDR) data are an intermediate data product derived from the Raw Data Records using reversible operations. All higher order data products are derived from the EDR. An automated pipeline is used to process the EDR from the Raw Data Records. All data are stored in the 'DATA' branch of the directory tree. In addition to the data files, anciliary information is stored in a separate PDS label (.LBL) file. Information about data gaps and other issues affecting the quality of the data can be found in the Confidence Level Note in the data set catalog (grand_l1a_ceres_ds.cat) Users of these data are encouraged to acknowledge both the PDS and the principal investigators of the instruments whose data are used in analysis in all publications. ============================================================================== Volume Set Information ============================================================================== This volume is part of the GRaND raw level-1A EDR data volume set. This volume set includes the following volumes: Volume ID Description --------------------------------------------------------- DWNXGRD_1A Dawn GRaND L1-A EDR Earth-Vesta cruise data DWNMGRD_1A Dawn GRaND L1-A EDR Mars flyby data DWNVGRD_1A Dawn GRaND L1-A EDR Vesta Encounter Archive DWNXCGRD_1A Dawn GRaND L1-A EDR Vesta-Ceres cruise data DWNCAGRD_1A Dawn GRaND L1-A EDR Ceres Approach to HAMO Archive DWNCLGRD_1A Dawn GRaND L1-A EDR Ceres LAMO Archive DWNC1GRD_1A Dawn GRaND L1-A EDR Ceres Extended LAMO (CXL) Archive DWNC2GRD_1A Dawn GRaND L1-A EDR Ceres Extended Juling (CXJ) Archive DWNC3GRD_1A Dawn GRaND L1-A EDR Ceres Extended GRaND (CXG) Archive DWNC4GRD_1A Dawn GRaND L1-A EDR Ceres Extended Opposition (CXO) Archive ============================================================================== Mission Facts ============================================================================== The "Dawn Ceres Science Orbits and Phases" table below provides a list Dawn Ceres Encounter mission phase start dates. ------------------------------------------------------------------------------ Dawn Ceres Science Orbits and Phases ------------------------------------------------------------------------------ start date (DOY) Orbit Phase Name (ID) Orbit Radius ------------------------------------------------------------------------------ 2014-12-26 (360) Approach CERES SCIENCE APPROACH (CSA) 2015-04-24 (114) RC3 CERES SCIENCE RC3 (CSR) ~14,000 km 2015-05-09 (129) Transfer CERES TRANSFER TO SURVEY (CTS) 2015-06-04 (155) Survey CERES SCIENCE SURVEY (CSS) ~4870 km 2015-07-01 (182) Transfer CERES TRANSFER TO HAMO (CTH) 2015-08-17 (229) HAMO CERES SCIENCE HAMO (CSH) ~1950 km 2015-10-23 (296) Transfer CERES TRANSFER TO LAMO (CTL) 2015-12-16 (350) LAMO CERES SCIENCE LAMO (CSL) ~850 km 2016-06-19 (171) XMO1 CERES EXTENDED LAMO (CXL) ~850 km 2016-09-02 (246) Transfer CERES EXTENDED TRANSFER TO JULING (CTJ) 2016-10-10 (284) XMO2 CERES EXTENDED JULING (CXJ) ~1950 km 2016-11-03 (308) Transfer CERES EXTENDED TRANSFER TO GRAND (CTG) 2016-12-13 (348) XMO3 CERES EXTENDED GRAND (CXG) 8.0-9.2e3 km 2017-02-23 (054) Transfer CERES EXTENDED TRANSFER TO OPPOSITION (CTO) 2017-04-28 (118) XMO4 CERES EXTENDED OPPOSITION (CXO) 1.4-5.0e4 km ------------------------------------------------------------------------------ GRaND, as a time-series instrument, does not easily conform to arbitrary mission phase boundaries. Raw telemetry data are queried from the telemetry database weekly and delivered to the GRaND team. In general, there is a one-to-one correspondence between the time intervals contained in the raw data queries and those in the 1A EDR data files. The 1A data files are loosely grouped into mission phases and the 1B processing produces a single file per "phase". The Ceres extended mission was proposed with several new "orbits" at various radii that were designed to achieve various objectives (Level-1 requirements). The orbits were creatively named Extended Mission Orbit X or XMO1, XMO2, ... XMO1 remained at the LAMO altitude and is also called extended LAMO or CXL. XMO2 was near the HAMO altitude but slightly elliptical with the primary objective of observing Juling at different local times and illumination conditions. This orbit is also referred to as the Juling orbit or CXJ. XMO3 was even more elliptical with a minimum altitude of ~7500 km where the GRaND instrument no longer detects the presence of Ceres. The purpose of this orbit was to collect GRaND background data at an altitude where the surface of Ceres could still be monitored with the other instruments. This orbit is also called the GRaND orbit or CXG. Lastly, the orbit altitude was raised high enough for the orbit plane to be changed (XMO4) so that the Ceres "opposition surge" could be observed at zero phase. This orbit is also called "Opposition" or CXO. ============================================================================== File Formats ============================================================================== The data files on this volume are in both ASCII and IEEE binary. Each data file has an detached ASCII header (PDS label). The PDS label contains information describing spacecraft, target, and data record format. A data set description, instrument description, and other PDS documents are in .CAT files in the /CATALOG directory. Additional documentation is generally located in the DOCUMENT directory. Note for Windows users: In more recent versions of the Microsoft Windows operating system the .CAT by default is reserved as 'Security Catalog.' The .CAT files contained in this volume are ASCII text files, and can be read by any form of text editor. To make Windows open files with this name extension as text files, do the following. In Windows Explorer, open the 'Tools' menu and select 'Folder Options'. Select the 'File Types' tab and select 'CAT' from the list. Press 'Change...' and then choose your preferred text editor or viewer. We do not know of any harmful effects this might have on the operating system or other programs, but do not guarantee it will be entirely safe to make this change. If problems occur, the change can be undone in the same 'File Types' window by changing the default application back to 'crypto shell extension'. ============================================================================== Errata ============================================================================== Every effort has been made to assure that the data and documentation are of the best possible quality. However, mistakes are inevitable. There is a file called ERRATA.TXT found at the root level of this volume which contains a list of known deficiencies or caveats associated with data on this volume at the time this volume was produced. ============================================================================== Volume Contents and Structure ============================================================================== This section describes the volume structure and naming conventions. Below is a tree diagram of the volume, followed by a description of the directory function and key files in each directory. DWNC3GRD_1A (root directory) | |- AAREADME.TXT Describes volume contents, and organization (this file) | |- ERRATA.TXT Describes known deficiencies or caveats in the data or | on this volume. | |- VOLDESC.CAT High level description of volume contents. | |- [BROWSE] Contains a GRaND Quick-look Reports for each interval of | GRaND science data contained in the DATA directory. A more | detailed description of the contents of this directory is | provided in the file /BROWSE/BROWINFO.TXT. | |- [CATALOG] PDS catalog files containing information describing the | data, instrument, instrument personnel, relevant references, | the spacecraft, and mission. A more detailed description of | the contents of this directory is provided in the file | /CATALOG/CATINFO.TXT. | |- [DATA] Contains the images. The images are divided up into separate | subdirectories by mission subphase, observation interval. | |- [DOCUMENT] Contains documents describing the instrument, and data | acquisition, processing, and usage. A more detailed | description of the contents of this directory is provided in | the file /DOCUMENT/DOCINFO.TXT. | |- [EXTRAS] Contains files which facilitate the use of the data on the | disk, but which are not actually required for the use or | understanding of those data. A more detailed description of | the contents of this directory is provided in the file | /EXTRAS/EXTRINFO.TXT. | |- [INDEX] Contains a table of contents for all files located on this | volume, and the volume set to date. A more detailed | description of the contents of this directory is provided in | the file /INDEX/INDXINFO.TXT. ============================================================================ Contacts ============================================================================ This volume was produced for the Planetary Data System (PDS) at the Small Bodies node. The data, and associated metadata were supplied by Dr. Thomas H. Prettyman, of the Planetary Science Institute. The volume was assembled at the Dawn Science Center (DSC), by Joseph N. Mafi. For questions or problems regarding the volume, please contact Dr. Carol Neese at the PDS Small Bodies Node: Email neese@psi.edu Telephone 520-622-6300 Mail Carol Neese Planetary Science Institute 1700 E. Ft. Lowell, Ste. 106 Tuscon, AZ 85719-2395 USA For question regarding the data, please contact Dr. Tom Prettyman of PSI: Email prettyman@psi.edu Telephone 520-622-6300 Mail Planetary Science Institute Albuquerque, NM USA For questions regarding PDS Standards or other archives available from the PDS, please contact PDS Operator at the PDS Engineering Node (at JPL): Email pds_operator@jpl.nasa.gov Telephone 818-354-4321 Mail Planetary Data System, PDS Operator Jet Propulsion Laboratory Mail Stop 202-101 4800 Oak Grove Dr. Pasadena, CA 91109-8099 USA The PDS assumes no legal liability for errors on this disk. All users are encouraged to verify the correctness of the data prior to submitting any publications or other work based on these data. Please report errors on this disk to the Small Bodies Node of the PDS through the ERRATA reporting procedures described above.