**MEMORANDUM OF UNDERSTANDING**

**I. PURPOSE **

The purpose of this Memorandum of Understanding (MOU) is to provide
information about the relationship among the various parties to this MOU
regarding their respective roles, duties, obligations and
responsibilities for implementation of the archiving of the high
resolution data obtained by the Cluster Wideband (WBD) Plasma Wave
Receiver. Parties to this document propose to coordinate and perform the
functions described herein within the scope of their various
governmental mandates, contracts and grants.

**II. PERIOD OF RELEVANCE**

This MOU is designed to serve as a record of the relationship of the
signatories from the date of its execution until* *the end of active
Cluster WBD operations* *unless modified by all the parties to the MOU.
The Period of Relevance will commence upon the date that all parties
have signed the MOU. A review may be conducted annually for modification
and/or amendment.

**III PARTIES TO THE MEMORANDUM OF UNDERSTANDING **

The parties to this MOU and their primary roles are delineated below:

-   [NASA HEADQUARTERS (NASA HQ), Washington, D.C.]{.underline}: NASA HQ
    will provide oversight to ensure that the Cluster WBD data are
    archived to their satisfaction.

-   [NASA GODDARD SPACE FLIGHT CENTER (GSFC), Greenbelt,
    MD]{.underline}: GSFC will ensure that that all of the parties to
    this MOU carry out their respective responsibilities.

-   [NATIONAL SPACE SCIENCE DATA CENTER (NSSDC), Greenbelt,
    MD]{.underline}: NSSDC will monitor the archival process and ensure
    that the data are being archived in a manner that will benefit the
    science community at large.

-   [THE UNIVERSITY OF IOWA (Iowa), Iowa City, Iowa]{.underline}: Iowa
    will prepare all of the Cluster WBD data obtained during the mission
    operations phase for archiving, including validation of same and
    accompanying documentation.

-   [SOUTHWEST RESEARCH INSTITUTE (SwRI), San Antonio,
    Texas]{.underline}: SwRI will act as the repository for the data and
    as the distributor of same to the science community.

**IV BACKGROUND **

The European Space Agency (ESA) Cluster spacecraft were launched in July
and August 2000, with commissioning of the scientific payload on all
four satellites taking place from September 2000 through January 2001.
The official mission operations phase (MOP) began on February 1, 2001.
The only scientific instrument on that payload that was funded solely by
the National Aeronautics and Space Administration (NASA) was the Cluster
WBD plasma wave receiver. A WBD instrument was mounted on each of the
four Cluster spacecraft. Virtually all of the WBD data obtained during
the Cluster mission up to the date of execution of this MOU have been
obtained by direct downlink to the Deep Space Network (DSN) ground
stations at Goldstone and Canberra and this is expected to remain the
case for the duration of the mission. The WBD data can also be recorded
onboard in a mode called Burst Mode 2, but this mode has been used only
once in the mission because it prohibits one of the other wave
instruments from taking data due to memory and processing
considerations, and because Burst Mode 2 reduces the WBD resolution to
1/3 of its capability. Furthermore, Burst Mode 2 is allowed by the other
instrument teams to occur only one hour per month.

Because WBD data are transmitted to the DSN ground stations at a very
high bit rate of 220 kbits/s, and because the Cluster spacecraft are not
always visible at Goldstone or Canberra, WBD data are obtained on a
limited basis only. The NASA requirement of DSN since the start of the
MOP phase has been to acquire two hours per spacecraft per 57-hour
orbit, or approximately 24 hours of WBD data per week. A modification of
this requirement in FY02 stated that these data were to be obtained
simultaneously from as many of the four spacecraft as possible, on a
best efforts basis. In addition, NASA requires DSN to perform at least
one guaranteed multi-spacecraft operation (MSO) per month, or two MSOs
on a best efforts basis. An MSO is a special operation that requires
that WBD data be acquired from at least three or four spacecraft
simultaneously for one hour with a pre- or post-operation calibration
lasting 10 minutes being performed. The calibration consists of the WBD
transmission from only one spacecraft being picked up by the three or
four ground antennas that are being used in the MSO. The purpose of this
calibration is to provide greater timing accuracy than can be achieved
with a normal DSN support (10 microseconds).

Based on the above data retrieval requirements, approximately 0.2 TBytes
of level 1 processed WBD data are produced each year. WBD data consist
of one-axis ac electric or magnetic field time series in the range 50 Hz
to 577 kHz with 5 to 35 microsecond time resolution depending on the
mode. Information on the instrument and its various capabilities can be
found in "The Wide-Band Plasma Wave Investigation", by D. A. Gurnett, R.
L. Huff and D. L. Kirchner, *Space Science Reviews*, 79, 195-208, 1997.
Level 1 processing consists of the following for each WBD transfer frame
(1096 bytes): unpacking the WBD status bytes, byte aligning the science
data, and determining the time of measurement based on the onboard clock
and on the DSN ground receive time stamp. Two time determinations for
the start time of each WBD transfer frame are made for the following
reason: the onboard clock time has an accuracy no better than 2 ms.
Since the time resolution of the WBD data can vary anywhere from 5 to 35
ìs, the onboard time clocks are not sufficient when performing
cross-spacecraft correlations, although they are sufficient for doing
large-time scale science or when comparing WBD data to data from other
Cluster instruments. When greater time accuracy is required, the 10 ìs
accuracy afforded by the DSN ground receive time tags must be used. In
obtaining the onboard clock time of measurement, only internal delays on
the spacecraft from actual time of measurement to the time that a time
stamp is applied by the onboard data handler are accounted for. When
applying the DSN ground receive time tags, the time of flight as well as
the spacecraft internal delays are taken into account. Information on
internal DSN delays, which are very small, can only be accounted for
during the MSOs when the special calibration is carried out. Iowa does
not make compensation for these DSN internal delays during MSOs, but
rather provides these data for anyone to analyze and apply the
appropriate time correction. In addition, separate "WEC time correction
files" will be made available by Sheffield University through the
Cluster Active Archive. These files provide time corrections, based on
data supplied by ESOC (European Space Operations Centre), which can be
applied to the onboard time tags provided in WBD's level 1 files that
will allow for 10 ìs accuracy of these onboard time tags.

Once Iowa has created a level 1 data set described above, these data are
validated through various tools developed at Iowa, and then the data are
written to DVDs. In addition to the level 1 WBD data, these DVDs also
contain documentation about the WBD instrument, example software to read
the level 1 data files, sample calibration routines, and information on
known problems. Since Iowa's current NASA grant, NNG04GB98G, and its
predecessor grant and contract did not provide for the archiving of
Cluster WBD data, the level 1 WBD DVDs are currently only disbursed to
the WBD Co-Investigators in the U.S. and to the Cluster data centers in
France, Sweden and the U.K., where the Principal Investigators of other
Cluster wave instruments reside.

**V RESPONSIBILITIES **

The responsibilities and agreements of each of the parties to this MOU
are set forth below.

[NASA HQ]{.underline}: NASA HQ will agree that once Iowa has archived
the Cluster WBD data obtained during the MOP phase of the Cluster
mission in accordance with this MOU, Iowa will not be held responsible
under any of its past, current or future grants for the archiving of the
Cluster WBD data in any other form or at any other location, unless
agreed to advance with Iowa.

[NASA GSFC]{.underline}: GSFC will ensure that all of the parties to
this agreement are carrying out their responsibilities in accordance
with this MOU. GSFC may request periodic written updates on the progress
of the archival progress from Iowa and SwRI.

[NSSDC]{.underline}: NSSDC will ensure, on behalf of NASA, that the data
are being archived in a fashion consistent with NASA and scientific
standards and that links to the data are provided through the NSSDC web
site.

[IOWA]{.underline}: Iowa, under its current NASA grant, NNG04GB98G, and
any future related grants, agrees to send a copy of the Cluster WBD
DVDs, as described in Section IV, to SwRI, for the period from the
beginning of the MOP phase through the end of active operations of
Cluster WBD. DVD shipments will contain one entire month's worth of
data. Iowa will also provide assistance and information to SwRI in order
for them to carry out their role as described below. Iowa accepts these
responsibilities for as long as they are carrying out active Cluster WBD
operations and processing new data. Completion of the delivery of these
DVDs will relieve Iowa of any other responsibility for archiving the
Cluster WBD data in any form at any other facility unless specifically
funded to do so.

[SwRI]{.underline}: SwRI will have the responsibility of ingesting the
Cluster WBD data obtained on the Iowa DVDs into their IDFS database.
These data, in calibrated or raw data number form, will then be made
accessible and downloadable to the science community in ASCII or CDF
format through a web interface. These data will become publicly
accessible after Iowa has insured that the validations are good. Iowa
will have at most six months for this validation activity after which
time the data will be publicly available. Validation primarily concerns
the time tagging of the WBD data as occasionally Iowa receives
information from either ESOC or DSN that certain timing problems exist
in the data during certain time periods, or Iowa uncovers systematic
problems that are not apparent from a single data set, but from several
data sets spread out over several months. Until the data are opened up
to general access, SwRI will provide the capability for the Iowa Cluster
WBD Principal Investigator, or his designee, to approve specific
requests from scientists to access the data during the restricted access
phase of any data set. SwRI will carry out these responsibilities under
a NASA grant or contract. Proper execution of the MOU assumes that both
Iowa and SwRI will be funded by NASA for performance of their respective
duties. A lapse in funding to either Iowa or SwRI will require that the
parties renegotiate this MOU. It is expected that the MOU will remain in
force for as long as Iowa is still carrying out active Cluster WBD
operations and obtaining new data.

**VI GENERAL PROVISIONS **

[PERFORMANCE GOALS]{.underline}: All parties to this MOU have agreed to
work together to provide an acceptable means of archiving the Cluster
WBD data, as described in Section V. Within one year of the date of
execution of this MOU, Iowa should have delivered to SwRI all WBD data
obtained during the Cluster MOP phase up to the current time. After that
current data will be delivered by Iowa to SwRI with a one- to two-month
lag from receipt of current data to time of delivery to SwRI. During the
first year after execution of this MOU, SwRI will write and implement
the necessary software to provide raw or calibrated data through its web
site. Thus by one year after the execution of this MOU, WBD data should
be routinely available for the entire Cluster mission through SwRI, with
new data being made available on a restricted basis within one to two
months after data capture and on a general basis within six months.

[PERFORMANCE REPORTING]{.underline}: GSFC may require Iowa and SwRI to
report on their progress and performance, in writing, not more often
than twice per year. If GSFC intends to request written reports, they
will inform all parties of their intention and provide the details of
the expected content of these reports.

[CONTINUOUS IMPROVEMENT]{.underline}: All parties to this MOU will work
to improve the processes being carried out so as to reduce the time
needed for the archival work.

[AMENDMENTS]{.underline}: Should amendments to this MOU be desirable or
necessary, all parties should be informed by the initiating party of
their desire to amend the MOU and the reasons for requesting an
amendment. The amendment will need to be agreed to by all parties.

[LONG TERM ARCHIVING SOLUTIONS]{.underline}: The parties agree to work
together to find a long term solution to the problem of getting the WBD
high resolution calibrated waveform data into the Cluster Active Archive
(CAA), which is an archive of the highest resolution data from all
Cluster instruments. Iowa has received funding from the Living with a
Star Targeted Research and Technology Program to meet a small part of
this objective. The funding will allow Iowa to archive all of its
documentation on the instrument and its operations as carried out, as
well as the overview spectrograms (typical WBD operations are 2-3 hours
each) and full time resolution spectrograms (30 seconds each) in the
CAA. The CAA, which contains all of the Cluster data, will eventually
become a part of the ILWS program. The graphical WBD data, together with
its documentation, will thus be available. It is Iowa's desire that the
WBD data archived at SwRI be made available to the CAA and the ILWS
program in the form of raw and calibrated waveforms. The possibilities
for how SwRI will accomplish this needs to be explored with NASA HQ and
NASA GSFC, with one possibility being that the SwRI web site act as a
mirror site for the CAA web site. The long term goal is to provide a
means for the high resolution WBD data to be available in both digital
waveform and graphical form throughout the lifetime of the Cluster
mission and for many years to follow as a part of NASA's Living With a
Star Program. **VI SIGNATURE **

By signing this Memorandum of Understanding, all parties have reviewed
the MOU and find it accurately reflects a general understanding of their
involvement in the archiving of the Cluster WBD high resolution data.

NASA Headquarters Date:

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NASA Goddard Space Flight Center Date

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National Space Science Data Center Date:

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The University of Iowa Date:

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Southwest Research Center Date:

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