Lunar Reconnaissance Orbiter

Radio Science

Archive Volume Software Interface Specification

version 1.1

April 19, 2011

SIGNATURE PAGE

Prepared by:

___________________ ____________

Gregory A. Neumann Date

LOLA Instrument co-Investigator

GSFC Code 698

Reviewed by:

___________________ ____________

David E. Smith Date

Principal Investigator, LOLA Instrument

GSFC Code 690.5

Approved by:

___________________ ____________

Stan Scott Date

LRO Project Science Data Manager

GSFC Code 451

Concurred by:

___________________ ____________

Susan Slavney Date

PDS Geosciences Discipline Node

___________________ ____________

Richard Simpson Date

PDS Radio Science Advisor

CHANGE LOG

TBD ITEMS

1.Introduction

1.1Purpose and Scope

This Software Interface Specification (SIS) describes the format and content of the Lunar Reconnaissance Orbiter (LRO) Radio Science (RS) Raw Data Archive (RDA). The LRO RS RDA represents the complete archive of raw data from investigations conducted using the radio and laser links between the LRO spacecraft and its tracking stations. The archive is generated by the Lunar Orbiter Laser Altimeter (LOLA) Science Operations Center (SOC). It is maintained and distributed by the Planetary Data System (PDS).

The communication, tracking, and timekeeping systems on LRO support generation of the precise geo-location needed by the LRO science and measurement investigations. The information provided by these systems is similar to conventional Radio Science data, although traditional 'radio science' was not an initial mission objective. The importance of the tracking data for all of the other LRO investigations merits its being archived for completeness and future analysis.

This SIS is intended to provide enough information to enable users to understand the format and content of the Archive. Typically, these individuals would be software engineers, data analysts, or planetary scientists.

The specifications in this document apply to all RS RDA volumes that are generated by the LOLA Science Team.

1.2Data Overview

The LRO RS RDA contains data collected at a number of locations that track and communicate with the spacecraft.

LRO is tracked via a network of Earth ground stations called the Space Communication Network (SCN). The SCN consists of the NASA Deep Space Network (DSN), a new dedicated 18-m S-band antenna at White Sands (New Mexico), a network of Universal Space Network (USN) S-band tracking stations, and the Next Generation Satellite Laser Ranging (NGSLR) station laser tracking station at the GSFC in Greenbelt, Maryland. The DSN was used during the LRO commissioning phase, but is not used for routine orbital operations. The primary USN stations supporting LRO are located at Dongara (Australia) and Weilheim (Germany), while backup stations are located at South Point (Hawaii), Kiruna (Sweden), and the Solar Dynamics Observatory (SDO) at White Sands. Coordinates of these stations are given in the INST.CAT file in the CATALOG directory.

LRO is tracked via the S-band network for 30 minutes of every lunar orbit. Tracking measurements consist of two-way coherent range and Doppler measurements. Radio doppler and range tracking to LRO's omnidirectional antenna and gimbaled, high-gain antenna (HGA) are the primary data source for this archive. The spacecraft Radio Frequency subsystems are described in detail in Tooley et al. (2010) [10].

LRO is tracked by the laser ranging station at GSFC whenever weather and geometry allow. The HGA carries a small, co-boresighted, optical receiver telescope. The laser range (LR) measurement consists of a one-way forward range measurement time-tagged onboard the spacecraft using an Ultra-Stable oscillator (USO). The laser range measurement is downlinked with science data. Ground processing is handled jointly by the LOLA SOC and the Crustal Dynamics Data Information System (CDDIS). Details of the LR subsystem are given in Zuber et al. (2010) [12] and in the LOLA instrument description by Smith et al. (2009) [9]. Ongoing participation by the International Laser Ranging Service (ILRS) network of stations continues to provide further LR data that are received and processed by the LOLA SOC.

Ka-band ground stations at White Sands (WS1 and WS2) collect downlinked science data but are not directly involved in LRO tracking.

1.3Content Overview

This SIS describes the format, content and generation of the LRO RS RDA. As this is a raw data archive, there is minimal processing of the data collected. Only the Geodyn SPK files can be considered ‘derived’ data. No plans exist for including other high level products in this archive.

This archive is delivered to the PDS by the LRO LOLA Science Team under the data set ID LRO-L-RSS-1-TRACKING-V1.0. The data set begins with the launch of LRO in June 2009, and is ongoing throughout the mission.

The following types of data are archived:

1. TRK: Tracking Data File; sent from the LRO tracking stations to the LRO Flight Dynamics Facility (FDF). These data are then transferred via the LRO Mission Operations Center (MOC) to the LOLA SOC.

2. WEA: Weather Data from the ground stations; contain information such as temperature, pressure, wind speed and relative humidity.

3. SFF: Small Forces Files from LRO FDF, describe the cumulative effects of thruster firing over given time intervals.

4. RANGE: Laser Ranging Data; one way laser ranging fire time. Data received by the LRO MOC, and processed into normal point and full rate data by the LOLA SOC.

5. SPK: Geodyn trajectory files from the LOLA Precise Orbit Determination Team, used for geolocation of LOLA data. These binary files contain spacecraft and planetary ephemerides, and are provided as an example of a product derived from the raw data in this archive.

These data can be classified as primary or ancillary. The spacecraft tracking data (TRK) and the Laser Ranging data (RANGE) are primary. All other files provided, with the exception of SPK files, are used to analyse and interpret tracking data, and can be classified as ancillary. The SPK files are derived products but are included here as an illustration of the utility of this dataset. Further details on the data types can be found in DATASET.CAT in the CATALOG directory.

1.4Applicable Documents and References

1. 453-HDBK-GN, Ground Network Tracking and Acquisition Data Handbook, 453-HDBK-GN, 450/Exploration and Space Communications Projects Division, Goddard Space Flight Center, Greenbelt, MD, May 2007.

2. Gordon Chin, et al., Lunar Reconnaissance Orbiter Overview: The Instrument Suite and Mission, Space Sci. Rev. 129:391-419, 2007.

3. Q. Nguyen, W. Yuknis, S. Pursley, N.Haghani, D. Albaijes, O. Haddad, A High Performance Command and Data Handling System for NASA's Lunar Reconnaissance Orbiter, American Institute of Aeronautics and Astronautics, 9-11 September 2008.

4. M. Pearlman, C. Noll, J. McGarry, W. Gurtner, E. Pavlis, The International Laser Ranging Service, AOGS Advances in Geosciences: Solid Earth, 2008.

5. Planetary Data System Standards Reference, Version 3.8, JPL D-7669, Part 2, February 27, 2009.

6. R.L. Ricklefs, C.J. Moore, Consolidated Laser Ranging Data Format (CRD), For the ILRS Data Formats and Procedures Working Group, 2009.

7. R. Saylor, Lunar Reconnaissance Orbiter Project Mission Concept of Operations, LRO Project Document 431-OPS-000042, 2006.

8. R. Saylor, Lunar Reconnaissance Orbiter Project Mission Design Handbook, LRO Project Document 431-HDBK-000486, 2006.

9. D.E. Smith, M.T. Zuber, G.B. Jackson, G.A. Neumann, H. Riris, X. Sun, R.S. Zellar, C. Coltharp, J. Connelly, R.B. Katz, I. Kleyner, P. Liiva, A. Matuszeski, E.M. Mazarico, J.F. McGarry, A.M. Novo-Gradac, M.N. Ott, C. Peters, L.A. Ramos-Izquierdo, L. Ramsey, D.D. Rowlands, S. Schmidt, V.S. Scott III, G.B. Shaw, J.C. Smith, J.P. Swinski, M.H. Torrence, G. Unger, A.W. Yu, T.W. Zagwodzki, The Lunar Orbiter Laser Altimeter Investigation on the Lunar Reconnaissance Orbiter Mission, Space Science Reviews, 16 May 2009.

10. Craig R. Tooley, Martin B. Houghton, Richard S. Saylor Jr., Cathy Peddie, David F. Everett, Charles L. Baker and Kristina N. Safdie, Lunar Reconnaissance Orbiter Mission and Spacecraft Design, Space Sci. Rev. 150:23-62, 2010.

11. STDN724: Tracking and Acquisition Handbook for the Spaceflight Tracking and Data Network, Revision 5, Space Communications Program, Goddard Space Flight Center, Greenbelt, Maryland, 1990-2006.

12. Maria T. Zuber, David E. Smith, Ronald S. Zellar, Gregory A. Neumann, Xiaoli Sun, Richard B. Katz, Igor Kleyner, Adam Matuszeski, Jan F. McGarry, Melanie N. Ott, Luis A. Ramos-Izquierdo, David D. Rowlands, Mark H. Torrence and Thomas W. Zagwodzki, The Lunar Reconnaissance Orbiter Laser Ranging Investigation, Space Science Reviews, 150, 63-80, 2010.

2.Raw Data Archive Characteristics and Environment

2.1Instrument Overview

The communication, tracking, and timekeeping systems on LRO support the precise geolocation needed by the LRO science and measurement investigations. The information provided by these systems is similar to Radio Science data.

For further detail on the Radio Science “instrument”, please see INST.CAT, DATASET.CAT and MISSION.CAT in the CATALOG directory.

2.2Data Product Overview

The Small Forces Files, Station Weather, and Laser Ranging Data Files are ASCII format of variable-length. Tracking Data Files and Geodyn Trajectory Files are of binary format. The following table defines the file type, estimated file size, frequency of delivery and source of files.

2.2.1Data Product Descriptions

Tracking Data File:

The Tracking Data File provides the data required to support tracking of the orbiter and generation of orbit and mission products. Each ground station (WS1 and the USN stations) that supports tracking for the LRO mission will create the data in a format identified as the Universal Tracking Data Format (UTDF) [1, 11].

Weather Data File:

The Weather data are in an ASCII, space-delimited file format [11]. The file consists of multiple lines in which the first line contains start date (YYYYMMDD), Day of Year (DDD), and station identifier information and then there are 2:N repeating lines that provide the following information: time reference, temperature, pressure, relative humidity, and wind speed.

Small Forces File:

The Small Forces File (SFF) is the Updated Thruster Calibration Parameter Report (FDF-25) and the file includes updated parameters for the thruster calibration based on all available information received about past maneuvers [11]. This is an informational report that provides the Post-Maneuver Calibration. It provides the final assessment of how well the maneuver was executed and it uses best pre-maneuver and post-maneuver orbit solutions, and telemetry (pressures, duty cycles, and attitude) to determine a thrust scale factor that can be used to plan future maneuvers (as long as they use the same thruster set).

Laser Ranging File:

The Laser Ranging file contains the LOLA/SOC–processed one-way laser ranging fire times from data processing based on the telemetry that LOLA receives from the LRO MOC as part of the real-time and post-pass spacecraft and instrument housekeeping and measurement telemetry, and from station dependent fire time files retrieved from the Crustal Dynamics Data Information System (CDDIS) which contains files from the Next Generation Satellite Laser Ranging (NGSLR) and participating International Laser Ranging Service (ILRS) laser ranging sites. The Laser Ranging files are ASCII files [6].

Geodyn Trajectory Files:

The Geodyn Trajectory Files (SPK) are orbit reconstructions produced by the LOLA Precise Orbit Determination (POD) Team. They are used for geolocation of LOLA data – in the processing of LOLA EDRs to RDRs – and to further refine POD. These files give spacecraft and planetary ephemerides and are identical in (binary) format to SPK files (see below) generated by the LRO Flight Dynamics Facility (FDF) Team. There are some differences between the two types of SPKs – the FDF SPKs are each exactly a day long, and have discontinuities at the day boundary. Geodyn SPKs are cut at the maneuvers corresponding to mission sub-phase changes (approximately monthly). Within each such period they should have no discontinuities. The FDF SPKs can be found at naif.jpl.nasa.gov.

2.3Data Processing

The SOC forms the full-rate laser ranging data by matching the station laser fire times with the LOLA received times from the instrument science data telemetry. The normal point data are generated using 5-second segments of ranging data. With the exception of the SPK files, no additional Radio Science data processing is performed.

2.4Software

No software is provided with this archive. Relevant, useful tools for accessing SPICE data are found at the PDS node naif.jpl.nasa.gov.

2.5File Naming Conventions

The file naming conventions used by the originating teams and repositories are preserved at the LOLA SOC, and modified only so as to meet naming requirements of the PDS. The naming convention for data files is described. The corresponding PDS label will bear the same file name as the datafile it describes, except for the file extension LBL.

Tracking Data File:

<File Qualifier>_<Spacecraft Designations>_<Receiver PADID>_<Date Information>.<Ext>; where

File Qualifier => 6 ASCII characters to identify the type of UTDF data

LSUTDF (indicates low-speed UTDF data)

Spacecraft Designations => 6 ASCII digits (SSSSVV) to identify the spacecraft

SSSS = Spacecraft ID (0059 for LRO)

VV = Vehicle ID number (01 for LRO)

Receiver PADID => 3 ASCII digits identify the receive station. Note that the PADIDs are subject to revision.

188 White Sands station

189 SDO backup station

103 USN Dongara

105 USN South Point, Hawaii

126 KU1S (or KU2S) - Kiruna, Sweden

128 WU1S (or WU2S) - Weilheim, Germany

Date Information => 13 ASCII characters, including two underscores, in the form of YYYY_DDD_HHMM to represent the date and time (UTC) when the station closed the data file;

YYYY 4 ASCII digits for year (2008 -2013)

DDD 3 ASCII digits for day of year (001 – 366)

HHMM 4 ASCII digits (24 hour time qualifier)

Ext => 3-character ASCII extension; TRK (default)

For example a White Sands generated low-speed UTDF tracking data file that was closed at 0957UTC on 25 January 2009 would be named: LSUTDF_005901_188_2009_025_0957.TRK

Station Weather Data File:

<Station ID>_<Station AOS Contact Time>.<Ext> ; where

Station ID => 4 ASCII characters for the station ID

WS1S White Sands

USPS USN Dongara

USHS USN Hawaii

KI3S Kiruna, Sweden

WG1S Wilheim, Germany

Station AOS time => 11 ASCII digits, plus one underscore character, in the form of YYYYDDD_HHMM, where AOS is Acquisition of Signal.

YYYY start year designator (2008 – 2013)

DDD start day of year (001 – 366)

HHMM – Hours and Minutes of AOS, UTC

HH (00 – 23)

MM (00 – 59)

Ext => 3-character ASCII extension, WEA

For example, a file name for a weather product from White Sands:

WS1S_2009040_0824.WEA

LRO Small Forces File:

<File Qualifier>_<Maneuver Type>_<Start Date>_<Stop Date>_<Version number>.<Ext>; where

File Qualifier = [5 Characters], for file designator; in this case, FDF25

Maneuver Type = [4-5 Characters] for the type of planned maneuver in the form of

MCCn Mid-course correction maneuver #n

LOIn Lunar Orbit Insertion maneuver #n

MOIn Mission Orbit Insertion maneuver #n

Note: The “n” for the MCC, LOI, MOI can have the suffix of “E” to represent that this is an engineering pre-burn to test the thrusters prior to the official maneuver

Sknna Station keeping maneuver #nn [either “A“ or “B” as each station keeping maneuver will consist of 2 parts], for example SK01A, SK01B,

Start Date = [7 characters] seven ASCII digits for the start date in the form of YYYYDDD; where

YYYY 4 ASCII digits for start year

DDD 3 ASCII digits for start day of year

Stop Date = 7 ASCII digit for the stop date in the form of YYYYDDD; where

YYYY 4 ASCII digits for stop year

DDD 3 ASCII digits for stop day of year

Version number = [2 characters] Two ASCII digits for version number, ranging from

01 to 99

Ext = [3characters] TXT, indicating a text file format for the FDF file.

Example: a file name for the first version of a Small Forces File corresponding to the first Mission Orbit Insertion maneuver would be written as

FDF25_MOI1_2009015_2009016_01.TXT

LRO Laser Ranging File:

The Laser Ranging files are named using the convention <station_id>_<Date>.<Ext>

where

station_id [4 characters] is used to define the laser ranging station site, e.g. GO1L

Date YYYYMMDDHHMM ; where Date corresponds to the date and time the recording of that particular Normal Point file begins.

YYYY 4 digit year (2009 – 2013)

MM 2 digit month (01 – 12)

DD 2 digit day (01 – 31)

HH 2 digit hour, UTC (00 – 23)

MM 2 digit minute, UTC (00 – 59)

Ext 3 characters; standard file extension for a Normal Point file: NPT

For a list of Laser Ranging stations, their coordinates, and their corresponding IDs/Codes please see the Appendix. Please note that in file naming, some stations have chosen to use the station ID (numbers) rather than Code (numbers and letters). The LOLA Science Team has preserved the original naming schemes for the data as transmitted to us.

Sample file name: an LR data file starting on January 20, 2009 at 1535 UTC in normal point mode recorded at Greenbelt NGSLR (GO1L) would be GO1L_200901201535.NPT

GEODYN Trajectory Files:

GEODYN SPK files are monthly orbit reconstructions produced by the LOLA Precise Orbit Determination Team in NAIF binary format.

File names have the form LRO_XX_NN_DATE.BSP.

XX mission phase: Commissioning (CO), Nominal Mission (NO),

Science Mission (SM) or Extended Mission (EM)

NN lunar month number (starting from 01), where the month is defined by station

keeping maneuvers rather than the civil calendar.

DATE the date this file was created, in the format YYYYMMDD

(a proxy for version number)

Commissioning mission phase files do not have a corresponding lunar month number, and have the form LRO_XX_DATE.BSP.

2.6Data Product Labels

PDS labels accompany all files contained on the LRO Radio Science RDA volume. The label can either be attached to (embedded in) the associated file, or it can be detached from it, in which case the label becomes a file in its own right with the same name as the associated file except for the extension LBL. Detached label files are located in the same directory as the associated file. Except for the files in the root and CATALOG directories (and some INFO.TXT files in several directories), all files have detached labels. Files that are pointed to from within a label file can be found either in the DOCUMENT or LABEL directory.

PDS labels provide descriptive information about the associated file. The PDS label is an object- oriented structure consisting of sets of "keyword=value" declarations. Although they are mostly self-descriptive, the format and values of the keywords are fully described in the PDS Data Dictionary (http://pds.nasa.gov/tools/ddlookup/data_dictionary_lookup.cfm).

3.ARCHIVE ORGANIZATION

The LRO Radio Science RDA volume consists of a root directory containing the directories CATALOG, DATA, DOCUMENT, INDEX, and LABEL. In addition, the root directory contains files pertinent to the entire volume. A description of these files and directories is provided below.

3.1Root Directory

The root directory contains the following ASCII files:

3.2CATALOG Directory

The files in the CATALOG directory provide high-level descriptions of the mission, the spacecraft, the ground system, and the data set. All are ASCII files. The files in this directory are coordinated by the PDS data engineer, who is responsible for loading them into the PDS catalog. The following files are found in the CATALOG Directory.

3.3DATA Directory

The DATA directory contains five subdirectories corresponding to file types TRK, WEA, SFF, RANGE, and SPK. Subdirectories are created only if there are corresponding data files (there are no empty subdirectories).

3.4DOCUMENT Directory

The DOCUMENT Directory contains documentation to help the user understand and use the archive data. The following files are contained in the DOCUMENT Directory.

3.5INDEX Directory

The INDEX directory contains the following files:

3.6LABEL Directory

The LABEL Directory contains files that describe data format and organization. These files are referred to in the PDS labels that accompany the data products. They are "include" files that are intended to be parsed as if they were part of the PDS labels that refer to them. The LABEL directory contains the following files:

4.RELEVANT Data Archived at Other Sites

4.1NAIF

The Navigation and Ancillary Information Facility (NAIF) is the navigation node of the PDS. NAIF archives navigation, attitude, and some instrument data for virtually all National Aeronautics and Space Administration (NASA) missions and provides the SPICE utility software to manipulate those data. The following table contains the list of SPICE kernels that are archived at NAIF and that are useful for radio science analysis and investigations.

NAIF SPICE archive files:

NAIF sites useful for LRO analysis are:

4.2ILRS

The Crustal Dynamics Data Information System (CDDIS) hosts the International Laser Ranging Service (ILRS) in which satellite laser ranging data from the world wide network are archived. The normal point and full rate LR data are part of that archive. This archive will contain a subset (normal point) of that dataset.

ILRS also maintains and revises the coordinates of the laser ranging stations, which can be found at their website.

ILRS sites useful for LRO analysis are:

5.Support Staff and Cognizant Persons

David E. Smith, LOLA Principal Investigator, NASA Goddard Space Flight Center (GSFC)

Maria T. Zuber, LOLA Deputy P.I., Massachusetts Institute of Technology

Gregory A. Neumann, LOLA co-Investigator, NASA Goddard Space Flight Center

Mark H. Torrence, LOLA Science Operations Manager, NASA Goddard Space Flight Center

Kopal Jha, LOLA Support Scientist/Data Archivist, NASA Goddard Space Flight Center

Susan Slavney, PDS Geosciences Node, Washington University, St. Louis, Missouri

Richard Simpson, PDS Radio Science Advisor, Stanford University, Stanford, California

Annette Conger, LRO RS Data Archivist, NASA GSFC Wallops Flight Facility

Appendix A: Coordinates of Data Receiving Stations

The data in this Appendix are duplicated in INST.CAT.

The USN station positions are given in the table below, in geographic coordinates (WGS-84 Ellipsoid):

The body-fixed coordinates of the tracking stations (X, Y, Z):

Name	Code	Coordinates
		x (km)	y (km)	z (km)
USN_Kiruna_1	KU1S	2246.85	865.44	5886.84
USN_Kiruna_2	KU2S	2247.56	865.48	5886.61
USN_Wilheim_1	WU1S	4206.09	824.08	4708.43
USN_Wilheim_2	WU2S	4206.03	823.94	4708.52
USN_Hawaii	USHS	-5496.59	-2486.04	2064.93
USN_Dongara	USPS	-2389.2	5043.29	-3078.46

The datadownlink stations are:

Coordinates of the Laser Ranging stations that track the LRO HGA:

DSN or other network stations that participated during commissioning: