Mars Atmosphere and Volatile Evolution mission MAVEN The mission’s goal is to explore the planet’s upper atmosphere, ionosphere, and interactions with the Sun and solar wind. Scientists will use MAVEN data to explore the loss of volatile compounds—such as CO 2, N 2, and H 2 O— from the Martian atmosphere to space. –Imaging and Ultraviolet Spectrometer (IUVS) –Neutral Gas and Ion Mass Spectrometer (INGIMS) –Extreme Ultraviolet Monitor (EUV) –Langmuir Probe and Waves (LPW) –Magnetometer (MAG) –Solar Energetic Particle (SEP) –Suprathermal and Thermal Ion Composition (STATIC) –Solar Wind Electron Analyzer (SWEA) –Solar Wind Ion Analyzer (SWIA)

MAVEN MAVEN along with LADEE were the first missions to archive data by using PDS 4. PDS 4 was being developed in parallel with MAVEN. Mission personnel were not all familiar with archiving in PDS. It was decided that PPI personnel would create the metadata for the particles and fields instruments (MAG excepted). MAVEN science data are delivered to PDS, the PPI writes the metadata and then the combined metadata and science data are peer reviewed. MAVEN particles and fields data (MAG excepted) were provided in the Common Data Format (CDF).

The CDF Challenge Define a version of CDF that is compatible with both the Heliophysics Data Environment (HPDE) and Planetary Data System standards. About four years ago a small group from HPDE described a set of minimum requirements for an archive quality CDF file called CDF-A. Earlier this year a group from both HPDE and PDS were chartered to define a version of CDF-A that could be completely described by PDS 4 metadata and thereby enable the archived data to be read by using tools that are compatible with PDS4.

CDF-A Team Community members from a range of stakeholders. Team included: Ed Grayzeck (NASA + GSFC + PDS) Aaron Roberts (NASA + HPDE + GSFC) Jim Thieman (HPDE + SPASE + GSFC) Bob McGuire (GSFC + CDF) Bobby Candey (GSFC + CDF) Ray Walker (PDS/PPI + NSF) Todd King (PDS/PPI + SPASE) Reviewed by: Dave Heather (PSA) Baptiste Cecconi (IPDA + LESIA)

CDF-A Specification Defines a core set of minimal features of a CDF file to be considered of archival quality. Includes extensions for Heliophysics Data Environment (HPDE) and Planetary Data System (PDS). Is the guiding document PPI uses when considering archiving of data in the CDF format. Available at:

CDF-A Requirements A CDF file meets a minimum set of requirements for data archiving when: The file contents comply with a released version of the CDF format specification. The file includes at least a minimum set of metadata, as defined by the ISTP metadata guidelines with SPDF extensions. All data variables which are part of the CDF file are included in the same file.

PDS/CDF-A PDS4 metadata can describe data that are stored as contiguous arrays. For a CDF file to meet PDS4 requirements it must adhere to all the CDF-A requirements and must also meet the following conditions: 1. The CDF file must be CDF version 3.4 or later. 2. No compression (file or variable). 3. No unused records. (No superfluous, non-decodable records) 4. No fragmented variables (all data for a variable must be contiguous in the file). 5. No sparse variables. All data values are physical (data for all dimensions in a variable are written) 6. No virtual (calculated) variables. 7. Variables are stored in row majority order. 8. Use only "zVariables" for data.

Working with MAVEN Data in PDS/CDF-A In a PDS4 label both the data and structures in a CDF-A file are described. –Data are described as objects in the core (base) PDS4 information model. –Structures are described with a discipline specific information model (local data dictionary)

CDF-A Data in a PDS4 Label In a PDS4 label the data in a CDF-A file are described as Array objects Element_Array are the observation values Axis_Array define the dimensions of each axis and assign a name to the axis. diff_en_fluxes Last Index Fastest Calibrated Differential Energy Flux IEEE754MSBSingle ev/[eV cm^2 sr s] epoch phi_coarse 16 2 dindex 4 3 energy_coarse 48 4

CDF-A Structures in a PDS4 Label Structures have a classification. In this case “Particle_Observation” The primary value use the local internal reference to point to the Array. The axis values use the local internal reference to point to the Array diff_en_fluxes Calibrated Differential Energy Flux diff_en_fluxes particle_observation_to_observation_values Epoch particle_observation_to_axis_values 1 phi_coarse particle_observation_to_axis_values 2 and so on…..

The PDS4 label can be parsed to generate a plot. Generated with a Phython script which parses the PDS4 label and reads the data based on offset, type and array size. No CDF library needed. More details at: Results!

NodeInstrumentRelease #1 StatusEst. Release ATMACCReview complete. PDS staging data.target Jul 17 IUVSReview complete. IUVS processing lien-resolved data.target Jul 20 IUVS KPSample data delivered. Updated SIS delivered. Review to begin after 7/15 (waiting for PDS to schedule). Remainder of data to be generated pending review. target Aug 1 NGIMSReview complete. Liens resolved. Errata delivered. Certified.RELEASED Jun 3 PPIEUVL2 review complete; in lien resolution. Certified with liens. L3 delivered to SDC, sample L3 delivered to PDS. Waiting for PDS to schedule review. (Target to be ready for 2 nd release.) RELEASED Jul 1 LPWReview begun 7/15. Comments due Aug 5. target Aug 7 MAGReview complete; in lien resolution. Certified with liens.RELEASED Jun 3 SEPData delivered. Awaiting updated SIS. Awaiting metadata generation. Review TBD. TBD STATICReview complete; in lien resolution. Certified with liens.RELEASED Jul 8 SWEAReview complete; in lien resolution. Certified with liens.RELEASED Jun 5 SWIAReview complete. Liens resolved. Certified.RELEASED Jun 3 AncillaryReview complete; in lien resolution. Certified with liens.RELEASED Jun 3 Insitu KPReview complete; in lien resolution. Certified with liens.RELEASED Jul 13 NAIFSPICE kernelsReview unnecessary. Certified.RELEASED Jun 3 MAVEN Release #1 Status 15 July 2015

MAVEN Release 1 First MAVEN data released: June 3 Release notification: 5:10 PM – 3 Jun 2015 First confirmed data use:5:52 PM – 3 Jun 2015

What we Leaned from MAVEN Source: Mitchell, Huber & Mafi presentations, PDSMC F2F, Berkeley, CA, Nov Initiate contact between PDS and the Mission early. a.PDS 4 is new to everyone. b. Face-to-face discussion is particularly useful. 2.Provide better early estimates of archiving costs. 3.Design archive schedule with mission activities in mind. 4.Identify archive conventions which the mission should establish early: a.Archive data products (raw, calibrated, high level) b.Archive organization (defining bundles/collections) c.File and archive product versioning scheme d.Directory and file naming conventions e.Time format(s) f.Data format(s)