Missions Provide Continuing Data Flows into Near-Line Archive

Volume 14, Number 2, June 1998
by H. Kent Hills

NSSDC receives data for its near-line archive (NASA Data Archive and Distribution System [NDADS]) from current missions in a quasi-continuous way or in a more intermittent way. Likewise, NSSDC receives some data from past missions in a quasi-continuous way over an extended period as large data volumes are gradually processed for archiving, although most data from past missions are received in one or a few submissions. This article focuses on the space physics data received in a quasi-continuous way. Quasi-continuous means data transfers at least as often as monthly. Note that NSSDC receives and disseminates much important data thereby excluded from this article.

For efficiency these continuing data streams are normally handled via an automated pipeline that results in archiving the data in the NDADS near-line data system and in selected cases also making the data World Wide Web (WWW)-accessible via the CDAWeb or other WWW interfaces. In some cases data files are pushed daily via network to directories on NSSDC's computers; in other cases the data come in at longer intervals. More easily generated semi-automated procedures are used in many cases where there may be multiple periodic submissions of data but not enough to justify setting up a completely automated run.

ISIS 1 and 2 Restoration Data

Two different international satellites for Ionosphere Studies (ISIS) 2 data sets are streaming in now, about five ingest runs per week: 1. Ionograms (digitized from Topside Sounder analog telemetry tapes). 2. Pulse coded modulation (PCM) data (digital telemetry from all experiments).

These two data sets come in via network as each ground-station pass is processed elsewhere at Goddard Space Flight Center under the direction of Dr. Robert Benson. The data files come in as processed, not necessarily in time order. Currently-archived data span the time range from April 1, 1973, to January 31, 1984.

NDADS also has higher level data products from ISIS 1 and 2. Electron density profiles (as deduced from the ionograms) are available for the time periods February 1, 1969 - May 30, 1980, for ISIS 1 and April 8, 1971 - August 27, 1979, for ISIS 2.

Two ISIS 1 data sets similar to those of ISIS 2 are being prepared for now: 1. Ionograms (digitized from Topside Sounder analog telemetry tapes). 2. PCM data (digital telemetry from all experiments).

The ingest procedure is in the testing phase now. ISIS 1 data are expected to start flowing to NSSDC in early June 1998.

ISTP and Associated Data

Data in Common Data Format (CDF), which includes Key Parameters (KP), some International Solar-Terrestrial Physics (ISTP) mission definitive data, and data from other missions contributing to ISTP are received via network from the ISTP, Central Data Handling Facility (CDHF). (In a few cases NSSDC makes the CDFs.) In addition to being stored near line in the NDADS system, these KP are also made available on line via NSSDC's WWW interface called CDAWeb, which offers both plot display and downloading of user-selected parameters. Data coverage includes selected data from several other spacecraft in addition to the "official" ISTP spacecraft missions and ground-based stations. The whole list includes the following:

Fast Auroral Snap Shot Explorer (FAST)
Geotail
Geostationary Operational Environmental Satellite (GOES) 6, 7, 8, 9
Interplanetary Monitoring Platform (IMP) 8
Interball (including ground-based)
Polar
Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX)
Solar and Heliospheric Observatory (SOHO) Particle Instruments
Wind
Geosynchronous Investigations
Los Alamos National Laboratory (LANL) spacecraft 1989-046A, 1990-095A, 1991-80B, and 1994-084A
Ground-Based Investigations
Canadian Auroral Network for the Open Program Unified Study (CANOPUS), Dual Auroral Radar Network (DARN), Severe Environmental Storms and Mesoscale Experiment (SESAME), and Sondestromfjord

The CDHF puts data into the pipeline with a normal delay time of only a few days, with a subsequent few days' delay for NSSDC ingest. The spacecraft data are from launch onward; other data cover the time span July 6, 1992, to present, although of course not all of the sources have data throughout this interval.

In cases where there are multiple versions of the data for a particular day, the NDADS system provides the latest version.

Other types of data, usually of higher time resolution than the KP, are also archived in NDADS (ISTP Level Zero data are distributed on CD-ROMs); more details by mission or by instrument type can be seen in the WWW Space Physics Catalog (SPyCAT) interface.

The FAST, SAMPEX, and Wind missions currently have the following data sets streaming into NDADS on a continuing basis. The FAST and SAMPEX data identified are in CDF and are considered by ISTP to be part of its suite or KP data. The Wind/Plasma and Radio Waves (WAVES) data are not KP data.
FAST (at 5-second resolution)
Electron Electrostatic (EES) Analyzer Survey Data (in CDF):
September 21, 1996 - March 24, 1998
Ion Electrostatic (IES) Analyzer Survey Data (in CDF):
September 21, 1996 - March 24, 1998
TEAMS (TMS) Survey Data (in CDF):
June 14, 1997 - June 15, 1997
SAMPEX:
30-Second Fluxes (both CDF and ASCII format):
July 6, 1992 - April 30, 1998 (For CDF: - June 30, 1997, temporarily delayed)
30-Second Rates (ASCII):
July 6, 1992 - April 30, 1998
Polar Cap Fluxes (both CDF and ASCII format)
July 6, 1992 - June 1, 1997 (For CDF: - May 30, 1997, temporarily delayed)
Polar Cap Rates (ASCII)
July 6, 1992 - April 30, 1998
Wind
WAVES
1-min binary digital spectra from RAD1, RAD2, and TNR receivers:
Ingest is beginning; RAD1 covers January 1, 1995 - February 28, 1998
Daily VLF-HF spectrograms, in PostScript and GIF formats:
November 10, 1994 - February 28, 1998
Plasma densities, in CDF format:
October 11, 1995 - Februry 25, 1998

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Author:Miranda Beall
Curators: Erin Gardner and Miranda Beall
Responsible Official: Dr. Joseph H. King, Code 633
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