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ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY
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Vol. 7, No. 7 31 Jul 1997 ISSN
1065-3597
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(C) 1997, Regents of the University of California
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Notes from the Editor
=====================
by Brett A. Stroozas, EUVE Mission/Flight Director
Welcome to the electronic newsletter for NASA's Extreme Ultraviolet
Explorer (EUVE) satellite, compiled and published monthly by the
Center for EUV Astrophysics (CEA) at the University of California,
Berkeley (UCB). The contents of this issue of the EUVE electronic
newsletter are as follows:
1. EUVE Science News
1.1 EUVE Celebrates Five Years in Orbit
1.2 EUVE Offers Coordinated Observations to XTE/ASCA Proposers
1.3 EGO Center Releases New Software and Calibration Data
1.4 Public GO/RAP Data Release for 1 Aug 1997
1.5 Abstracts of Recently *Accepted* EUVE Papers
2. EUVE Satellite Mission Operations News
2.1 DS/S Calibration Observation of HZ 43
2.2 FOT Conducts Star Tracker Engineering Tests
2.3 Science Payload Resets Itself
2.4 Ground Software Expanded to Include Automated Spacecraft Monitoring
2.5 On-Line Access to EUVE
3. EUVE Outsourced Extended Mission Status Report
3.1 New TPOCC Software Release Delivered
3.2 Progress on PACOR Replacement
To comment on or make suggestions for the EUVE electronic newsletter,
please send e-mail to ceanews@cea.berkeley.edu (Internet).
The EUVE observatory performed well throughout the month of Jun
1997, completing and/or beginning observations of the following Guest
Observer (GO) and Right-Angle Program (RAP) targets. For each target
is listed its name, its spectral type (generally from the SIMBAD
database), the observation start day/time (day-of-year:hours:minutes),
name of Principal Investigator (PI), observation type/priority, and
any relevant notes:
=======================================================================
Target SpT GMT Start PI T Notes^
=======================================================================
ksi UMa G0V 134:11:15 (14 May) Drake 1 EGO,CO1,RLL
EUVE J1725+021 NOID 134:11:15 (14 May) Lampton 1 RAP
Survey ---- 152:00:36 (01 Jun) ------ - EN1
ST Test ---- 152:06:34 (01 Jun) ------ - EN2
NGC 4051 AGN:Sy1 152:06:34 (01 Jun) Fruscione 3 RAP
EUVE J1659+440 WD:DAp 152:08:25 (01 Jun) Dupuis 1 EGO,SPI
EUVE J1706-450 NOID 152:08:25 (01 Jun) Wu 3 RAP
BATSE 1157 GRB 152:08:25 (01 Jun) Hurley 3 RAP
Abell 2199 ClGal 167:04:50 (16 Jun) Lieu 2 EGO
RXJ 1856.5-3754 NeutSt 169:04:20 (18 Jun) Walter 1 EGO
HZ 43 WD:DAw 176:00:20 (25 Jun) ------ - CAL,CFG,MU2,SPI
EUVE J1706-450 NOID 176:00:20 (25 Jun) Lampton 3 RAP
Payload Reset ---- 177:08:00 (26 Jun) ------ - ---
RXJ 1856.5-3754 NeutSt 177:15:50 (26 Jun) Walter 1 EGO
ALEXIS Trans NOID 178:21:58 (27 Jun) Bloch 1 EGO,TOO,MU3
HD 206860 G0V 178:23:28 (27 Jun) Portier 3 RAP
RXJ 1856.5-3754 NeutSt 179:02:37 (28 Jun) Walter 1 EGO
Jupiter SolSys 180:00:42 (29 Jun) Hall 2 EGO,MU6,CO2,TCO
RXJ 1856.5-3754 NeutSt 181:22:25 (30 Jun) Walter 1 EGO
=======================================================================
^Key:
CAL = Science calibration observation
CFG = Special configuration of science payload instruments
CO1 = Observation coordinated with the ASCA satellite
CO2 = Observation coordinated with the Galileo satellite
EGO = EUVE Guest Observer observation
EN1 = Survey mode engineering test to calibrate star trackers
EN2 = One-orbit, multiple-pointing (9) engineering test to map
"partial scan anomaly" area star tracker #2
MU2 = Multiple pointings (2) required for this observation
MU3 = Multiple pointings (3) required for this observation
MU6 = Multiple pointings (6) required for this observation
RAP = Right-Angle Program observation
RLL = Satellite roll change required during observation to
avoid anti-sun pointing constraint violation
SPI = Spiral dithered observation
TOO = Target of Opportunity
TCO = Time-critical observation
1. EUVE Science News
====================
1.1 EUVE Celebrates Five Years in Orbit
---------------------------------------
by Dr. Roger Malina, EUVE Observatory Director
Just over five years ago, on 7 Jun 1992 at 12:40pm Eastern time,
the EUVE satellite was launched from Cape Canaveral, FL. After five
years of on-orbit operations and science observations, the EUVE
spacecraft and science payload continue to operate flawlessly. We are
working hard to stretch the available funds in order to keep operating
EUVE until at least mid-1999. In the meantime, EUVE continues to
discover new EUV sources every day, the many unidentified sources
continue to be hunted down, the mystery of warm gas in clusters of
galaxies continues to animate controversy, and EUVE has just joined in
on the mystery of gamma ray bursters. For EUVE it is never a dull
moment and UCB looks forward to continued future collaboration with
the astronomical community. We ask that you please join us in wishing
EUVE a happy fifth birthday!!
1.2 EUVE Offers Coordinated Observations to XTE/ASCA Proposers
--------------------------------------------------------------
by Dr. Roger Malina, EUVE Observatory Director
The Extreme Ultraviolet Explorer (EUVE) satellite project is
pleased to announce that it will accept the decision of the XTE and
ASCA (US) peer review panels in granting time for coordinated
observations with EUVE. A successful proposal to either the XTE or
ASCA panel would not have to be re-submitted to an EUVE peer review to
get EUVE observing time. The EUVE project believes this
science-oriented, streamlined process will ease the burden on the
organizers of multi-wavelength campaigns and will enhance the science
return of the satellites.
Proposers who wish to take advantage of this opportunity must make
their case for EUVE observations in their proposal's scientific
justification. The EUVE project will conduct a technical review to
check the feasibility of the observation which will be reported to the
XTE and ASCA peer review committees. Therefore, it is in the
proposer's best interest to provide enough detail on expected EUV
flux, assumed hydrogen column, requested exposure and required
signal-to-noise ratio for a valid technical assessment. This offer is
meant to facilitate truly coordinated campaigns. Only enough EUVE
exposure time will be awarded to accomplish the goals of the
coordinated observation and not for independent EUVE science.
To minimize paperwork, the EUVE project will contact only
successful proposers for the detailed information needed (e.g., target
summary forms, PI contact address) to plan their observation.
Information on the capabilities of EUVE can be found on the WWW at
www.cea.berkeley.edu or via anonymous ftp at ftp.cea.berkeley.edu in
the directory /pub/nra96.
No funding is associated with this opportunity. There is currently
no reciprocity with XTE or ASCA in this offer; i.e., proposals for
coordinated observations to future EUVE NRAs will not be automatically
granted time on XTE or ASCA. The proprietary period for EUVE data is
six months from the date of data delivery to the PI. Standard GO
support for data delivery and analysis will be granted. CEA also
offers Guest Scientist computer accounts to aid in data analysis and
reduction.
Questions regarding this opportunity and/or the EUVE satellite can
be directed to egoinfo@cea.berkeley.edu.
1.3 EGO Center Releases New Software and Calibration Data
-------------------------------------------------------------
by Dr. Mark Abbott, EGO Support Scientist
The EGO Center announces the release of version 1.7 of the EUV
software package and version 1.14 of the EGODATA calibration dataset.
The descriptions that follow outline the main features of these
releases to help users determine if they need to update their
installations of these products. Please read the following sections
carefully as there are current and impending changes to the EUVE data
product formats. EUV 1.7 and EGODATA 1.14 may be obtained from the
CEA anonymous ftp site at ftp.cea.berkeley.edu in the directories
/pub/software/euv1.7 and /pub/reference/egodata1.14.
Data Format Changes and the EUVE Permanent Archive
**************************************************
The primary purpose for the new releases is to support the
production and use of the EUVE Science Archive, which, along with
the EUVE Telemetry Archive, forms the EUVE Permanent Archive.
Data contained in the EUVE Science Archive will be in a new data
format (the archive format). While the information content is largely
equivalent to the previous format used to deliver GO and archive data
(the GO format) for all science analysis purposes, the data has been
organized differently. This new format is necessary to meet the
stringent requirements of a long-term, permanent archive: it must be
stored with maximum adherence to portability and standards, and there
must be complete meta-data accompanying each observation that
describes the context of the data. The new format was also designed
to maximize the scientific return from the data while keeping the size
of the archive small enough that the data will be easily accessible by
the community.
As of EUV 1.7 the software package supports either data format;
there are no plans to remove software support for the GO format. So
users will continue to be able to analyze any old data sets that they
may already have.
As soon as it becomes available CEA will use data from the Science
Archive to satisfy requests for archival data. GO format data
products for old observations will be unavailable once equivalent
archive format data products exist. In the near future, another
document will be distributed that describes the archive format in
sufficient detail to enable researchers to begin to work with such
data. This document will include instructions on how to unpack
archive format data into files that closely resemble the GO format
ones -- QPOE files, IRAF images, ST Tables, etc. -- with which EUVE
users are familiar. Eventually, the EGO Center documentation (i.e.,
the User's Guides) will be rewritten to describe the new format and
its use in detail; this effort is expected to take several months.
To avoid the confusion and difficulty of providing long-term
support for delivery of data in multiple data formats, the GO format
will also be phased out and replaced by the archive format for
delivery of data to GOs of new observations. This phase-out will not
occur until after the completion of the new versions of the EGO Center
documentation. In the interim period, data from new observations will
be delivered to GOs in both formats. GOs are encouraged to begin
working with the archive format as soon as they are comfortable doing
so; the new archive products are, in some ways, easier to use than the
GO format products.
GO data format changes as of EUV 1.7
************************************
There are some changes to the GO format products as a result of the
reconfiguration of the analysis pipelines at CEA to produce both data
formats. They are described below in roughly decreasing order of
significance.
o Previously, the spectrometer QPOE files contained all of the events
from the detector, and the remapped images of the spectrometers
were constructed by extracting a horizontal strip from the QPOE
files. As of this release, the spectrometer QPOE files are also
filtered to contain only those events in that strip, and will be
substantially smaller.
o The size of the strip in the spectrometer QPOEs and images has
narrowed. The new strip is 300 lines high and centered at the
nominal position of the spectrum (line 1024). However, for
non-point-source targets, the strip will be eliminated altogether,
and all data from the spectrometers will be delivered.
o Previously, the deep survey (DS) data was prefiltered at telemetry
fetch time to contain only events from the Lexan filter, and then a
horizontal strip was extracted from the QPOE file in remapped
coordinates to create an image file. This typically resulted in a
trapezoidal appearance of the DS detector in the final image. The
strip extraction has been eliminated in the current release;the DS
remapped image will now contain the entire DS Lexan filter and will
now be substantially larger (2048 x 2048). This change will not
affect the contents of the DS QPOE file.
o The DS images are now filtered on quadrant counts. Previously,
these images were composed by filtering the DS event list with a
lower limit on analog-to-digital (A-D) counts (to establish an
exposure time) and limits on zenith angle (to remove earth-blocked
times). Now, an upper limit on quadrant counts is also in place to
remove South Atlantic Anomaly (SAA) times. This limit is 50 counts
per two major frames (one major frame equals 1.024 sec). For
certain very bright targets (such as the Moon), the upper limits of
the A-D count filters in the spectrometers will be raised to 150
counts per two major frames in order to avoid eliminating valid
data.
o Previously, all available telemetry was fetched for an observation
and placed into tables0-8 (except that only the Lexan filter is
included for the DS). All events went into the QPOE files.
Filters were then applied to removed SAA and earth-blocked times
when constructing images. As of this release, we now attempt to
only fetch telemetry for non-earth-blocked times. This will reduce
the amount of useless telemetry in the tables. However, this
prefiltering is fairly rough, so we still apply the usual
earth-blockage filter when building images to fine tune the
results.
o New processing steps have been added to the nominal reduction for
moving targets that substantially increase the usefulness of the
data as originally delivered from CEA. Using a target ephemeris we
now adjust the aspect correction to account for the target's
motion, including parallax due to the spacecraft's motion. This
procedure is performed using the aspcorr task for the
spectrometers, and using the new mapcorr task for the DS. The
remapped DS QPOE and image are now in a source-centered coordinate
system. For extended moving targets, we now apply a filter to the
events in detector coordinates to remove calibration stimpulser
events (stimpins) and secondary spectrometer filters, which would
otherwise contaminate the remapped images.
o QPOE files are now produced with pulse height information by
default, where it is available (only observations taken in WSZ mode
have pulse height data). Note that the definition of the pulse
height has been changed from the previous definition; the new pulse
heights are the previous ones divided by two. Since pulse heights
are generally used only in a relative sense within a single
observation, this should have no impact on analysis.
o Selected header cards have changed:
PI_NAME -- replaced by OBSERVER
JDREF -- deleted
OBSERVAT -- deleted
MJDREF -- added
TASSIGN -- added
CLOCKCOR -- added
RADECSYS -- added
TIMEREF -- added
TIMEZERO -- added
TELTYPE -- added
INSTRUME -- value changed
TELESCOP -- value changed
TIMESYS -- value changed
ORIGIN -- value changed
o Some new data files appear:
ds_quadct_gt -- DS quadrant count limits file
valid_times -- table of valid time intervals for this observation
For moving targets only,
corrected_aspect -- corrected aspect file (used in place of
table1)
ephemeris -- ephemeris used to correct aspect
o In DS and scanner QPOE files, the right ascension (RA) values now
run from 0 to 360 degrees, instead of -180 to 180 degrees.
o The data types of several of the columns in the primbsch table have
changed from float to int: telemetered counts (*tm), quadrant
counts (*Sf), and sum of quadrant counts (*SumQ). Some of the
column units have changed.
o The print formats of columns in the mkaspect output table have
changed. The RA column is now in degrees.
o A number of never-used monitors have been eliminated from the
auxiliary data tables (table1-8). As a result of this, table4 has
been eliminated altogether.
o Several unused columns were eliminated from the catalog table
(which contains the source position).
What's New in EUV 1.7
*********************
The majority of the changes to the EUV package take the form of
many small modifications enabling the tasks to work with the new
archive format data products. Many of these changes involve new or
changed task parameters, so you might need to "unlearn" several of the
tasks in IRAF before running them again. Many other compatibility
changes are behind the scenes and should not affect users. If you
expect only to have to work with old GO products, there may be no need
to update to EUV 1.7. Users who expect to work with archive format
data must upgrade to this release. Note that data delivered only in
archive format from CEA will no longer include a copy of the software
with the data, so you will have to get a copy from the CEA anonymous
ftp site.
For all details of the changes in the package tasks, see the file
revisions.hlp that accompanies the software.
o A new euvtools task, parallax, corrects an ephemeris of a source
position and distance for the effects of parallax due to the EUVE
spacecraft motion, producing another ephemeris file as output.
o A new euvtools task, mapcorr, takes a QPOE file containing events
mapped onto the sky and produces another QPOE file in which the
events are remapped relative to the position of a source. The
source position is read from an ephemeris file. The remapped
events can optionally be in a rotated frame, where the amount of
rotation is time-variable and is also taken from the ephemeris
file. Note that this task only applies to sky images (i.e., DS and
scanner) and does not work with spectrometer data. For the
spectrometers, you can still use the aspcorr task but it doesn't
allow for rotation.
o These tasks have had changed parameters and may have to be
unlearned:
aspcorr, backmon, cep, detpos, mkaspect,
qp2evttab, qpdup, qpmkim
The majority of these changes involve new parameters that allow the
user to specify the names of columns in input tables. This is
needed because some columns have different names in the GO and
archive formats. Previously, the GO format names were hard coded
into the programs. Generally, the default values of all of the
parameters are correct for working with GO format data, so users
with such data should be able to ignore the new parameters (after
unlearning the task).
o All tasks that manipulate RA information can now handle input in
either degrees or hours.
o Noteworthy bug fixes:
* Aspcorr now properly handles INDEF input values.
* Effexp now fails gracefully when intervals are specified via a
QPOE file, but no time filter is present.
o Mkprimbsch now produces a row-ordered output table. This may slow
the running time for this task substantially for a large table, but
it allows certain programs that read the primbsch table to operate
much more quickly.
o Qpmkim now has a parameter for specifying the quadrant to use for
primbsch correction, in the case where only one quadrant is
relevant. It no longer always needs to have primbsch corrections
available for all quadrants.
What's New in EGODATA 1.14
**************************
The changes to EGODATA are all in support of the changes in the EUV
package (primarily the cep task) and do not represent any new
calibrations. Therefore, there is no need to upgrade to this release
of EGODATA unless you are installing EUV 1.7. Note that data
delivered only in archive format from CEA will no longer include a
copy of EGODATA with the data, so you will have to get a copy from the
CEA anonymous ftp site.
For all details of the changes in EGODATA, see the file
contents.hlp that accompanies the calibration data.
o New spatial masks have been added, distinguishing the primary and
secondary filters in the spectrometer. This is for use in
filtering extended, moving targets.
o The cep scripts which compute pulse height have been modified to
produce a value which is half of the previous value.
o Several new cep scripts and data files have been added to permit
more flexible specification of input files to cep. This is to
allow cep to read archive products.
1.4 Public GO/RAP Data Release for 1 Aug 1997
---------------------------------------------
by Dr. Nahide Craig, EUVE User Support Scientist
The table below lists the GO/RAP observations that become public on
1 Aug 1997. For each observation is given the target name, the
approximate exposure time in ksec, the GMT start/end dates, the
target's spectral type, and the data identification code (GO and RAP
data are marked accordingly). All public data sets can be ordered
from the EUVE Science Archive via WWW and electronic or postal mail
(see addresses below). Please be sure to include in your order the
DataID(s) of interest. Processed data sets are shipped via postal
mail on 8mm tape or (if requested) on CD-ROM.
The data rights policies for observations state that Principal
Investigators (PIs) have proprietary rights to their data for a given
period of time from the date (s)he receives it. It is often the case
that long observations are broken up over many months; e.g., an
observation approved for 60 ksec may actually be observed for 10 ksec
one month, 20 ksec the next, and 30 ksec three months later. In such
cases the proprietary period begins after the PI is sent the final
piece of the completed observation. See the UCB/CEA WWW site (address
below) for a complete list of publicly available EUVE data products.
===============================================================
Target ~Exp GMT Observation Dates SpT DataID
Name (ksec) Start End
===============================================================
GO DATA SETS AVAILABLE 1 AUG 1997:
CYCLE 4 GO Targets
2EUVE J0858-00.2 25 07 Dec - 08 Dec 1996 NOID go0577
2EUVE J1100+34.4 28 10 Dec - 11 Dec 1996 NOID go0578
AR UMa 117 14 Dec - 18 Dec 1996 CV:AM go0579
alpha Col 186 27 Dec - 03 Jan 1997 B7IVe go0580
CYCLE 3 GO Targets
V815 Her 93 15 Jun - 19 Jun 1996 G5 go0581
RAP DATA SETS AVAILABLE 1 AUG 1997
HD 19373 25 07 Dec - 08 Dec 1996 G0V rap0117
EUVE J2112+501 58 21 Nov - 23 Nov 1996 WD:DA rap0118
1028+290 3 19 Nov - 19 Nov 1995 AGN rap0119
EUVE J0424+15.4 28 10 Dec - 11 Dec 1996 NOID rap0120
EUVE J0425+15.2 28 10 Dec - 11 Dec 1996 NOID rap0121
0633+1746 25 08 Dec - 09 Dec 1996 Pulsar rap0122
EUVE J0205+093 105 04 Nov - 08 Nov 1996 NOID rap0123
NOTE: RAP targets observed as of 15 Mar 1997 do *not* have
proprietary periods per the new EUVE Science Advisory policy.
================================================================
1.5 Abstracts of Recently *Accepted* EUVE Papers
------------------------------------------------
Included below are abstracts of EUVE-related papers recently
*accepted* for publication. For those papers authored by UCB/CEA
personnel, the UCB/CEA publication numbers are indicated. Unless
otherwise noted, researchers may obtain preprints of the UCB/CEA
papers by sending an e-mail request containing the publication
number(s) of interest to pub@cea.berkeley.edu.
Researchers are encouraged to contribute *accepted* EUVE-related
abstracts for inclusion in future editions of this newsletter and for
posting under the UCB/CEA/EUVE WWW site. Please send all abstracts to
archive@cea.berkeley.edu.
--------------------------------------------------------------
EXTREME ULTRAVIOLET PHOTOMETRY AND SPECTROSCOPY OF BL HYDRI
P. Szkody, S. Vennes, E.M. Sion, K.S. Long and S. B. Howell
To appear in Astrophysical Journal.
We have analyzed Extreme Ultraviolet Explorer (EUVE) observations
of BL Hyi obtained during a high accretion state in 1995 October. The
light curve obtained with the Deep Survey instrument reveals a broad
hump covering the phases when both poles have been known to be active
in X-ray. In contrast to the X-ray, both poles contribute a
comparable extreme ultraviolet (EUV) flux. The short wavelength
spectrum can be fit with either a relatively cool (5 eV) pure hydrogen
white dwarf or by a 17 eV blackbody; both fits imply a neutral hydrogen
column density in the local interstellar medium of ~3E+19 cm^(-2).
However, near simultaneous IUE far ultraviolet (FUV) spectroscopic
measurements rule out pure hydrogen white dwarf models with
temperatures less than 8 eV. BL Hyi has a cooler accretion area than
AM Her and VV Pup, but is similar in temperature to QS Tel. The total
EUV energy is (2-4)E+32 ergs/s which is only slightly larger than the
hard X-ray and cyclotron energy. This suggests that BL Hyi has a
conventional accretion column and that the polar cap is primarily
heated from above by radiation from the accretion shock, rather than
from below by dense blobs which penetrate the photosphere.
--------------------------------------------------------------
OUTSOURCING THE EXTREME ULTRAVIOLET EXPLORER (EUVE) MISSION FROM NASA
GSFC TO THE UNIVERSITY OF CALIFORNIA, BERKELEY
K. Hartnett, R.J. Oliversen, W. Guit, and B. Stroozas
To be presented at the AIAA Space & Defense conference, Sep 1997.
[CEA publication #TBD.]
The NASA Extreme Ultraviolet Explorer (EUVE) satellite was launched
on June 7, 1992. EUVE Project Management and Project Science
responsibilities at the time of launch were located at the NASA
Goddard Space Flight Center (GSFC) in Greenbelt, MD. Contracts were
awarded to 1) Lockheed Martin Space Mission Systems and Services
Corp. (LM), formerly Loral Aerosys, for the command and control of the
spacecraft (S/C) bus and 2) to the University of California at
Berkeley (UCB) for operation and management of the UCB-built EUV
payload and science data processing. In April 1996, UCB and GSFC
began the process of jointly "outsourcing" EUVE operations from GSFC
to UCB, including the operation of the S/C bus, the role of GSFC
Project Scientist, and ongoing Programmatic responsibility for the
mission. The transition was successfully completed in March 1997.
This paper provides details on the technical and programmatic
structure of the mission at the time of the outsourcing, the
procurement and technical processes undertaken to accomplish the
handover, various challenges encountered along the way, and an
enumeration of lessons learned.
--------------------------------------------------------------
2. EUVE Satellite Mission Operations News
=========================================
by Brett A. Stroozas, EUVE Mission/Flight Director
The month of Jun was a very busy one in EUVE mission operations.
During this time EUVE conducted a large number and wide variety of
observations: nine GO targets, six RAP targets, two engineering tests,
one science calibration, and an unexpected payload reset. One of the
GO observations -- the ALEXIS TOO -- was a target of opportunity; two
others, ksi UMa and Jupiter, were coordinated with the ASCA and
Galileo satellites, respectively; and the Jupiter, ALEXIS TOO, and HZ
43 calibration observations required multiple pointings. Jun was also
an exciting month because the operations staff received a new ground
system software release to autonomously monitor spacecraft telemetry
during the off-shift hours. Finally, in addition to celebrating
EUVE's 5-year launch anniversary, on 14 Jun we also celebrated our
first three-month anniversary of spacecraft operations at UCB. Some
of these operational highlights are discussed in the following
subsections.
2.1 DS/S Calibration Observation of HZ 43
-----------------------------------------
A calibration observation of the EUV-bright white dwarf star HZ 43
was carried out on 25-26 Jun. The purpose of this observation was to
use HZ 43 to measure any degradations on the Deep Survey/Spectrometer
(DS/S) telescope's four detectors: the deep survey, and the long-,
medium-, and short-wavelength spectrometers. This observation was
conducted as planned. Preliminary analysis of the resulting data
indicate some minor degradations that will require adjustments to
various flight detector parameters. After some additional analysis
UCB scientists and engineers will dictate the actual adjustments to be
made, and the FOT will then generate and uplink the relevant commands
to implement the adjustments on the payload.
2.2 FOT Conducts Star Tracker Engineering Tests
-----------------------------------------------
On 1 Jun the FOT conducted two back-to-back star tracker (ST)
engineering tests. The first test was a 6-hour survey mode
observation to calibrate the two STs. In these tests, which are
typically conducted every one or two months, the FOT commands the
spacecraft out of inertial pointing mode into survey (i.e., spinning)
mode. The resulting ST data was then forwarded to GSFC's Flight
Dynamics Facility for analysis.
The spacecraft was then "spun down" and commanded back into
inertial mode for the second engineering test. The goal of this
2-hour test was to attempt to localize the area in the field of view
(FOV) of star tracker #2 (ST-2) where, in the past, we've encountered
anomalous behavior -- the so-called "partial scan anomalies". These
anomalies result in degraded attitude knowledge, thereby negatively
affecting the quality of the resulting science data.
The test scenario consisted of slewing and rolling the spacecraft
to a specific attitude such that particular guide and so-called
"blocker" stars were properly positioned in the ST-2 FOV. After
sending a series of commands to direct ST-2 to acquire the guide star,
UCB engineers then observed the ST-2 behavior. The spacecraft was
then slewed slightly to offset the stars in the ST-2 FOV, and the
command and observation sequence was once again carried out. This
slew/command/observe sequence was repeated at nine separate attitudes,
thus mapping the ST-2 performance over the problem section of its FOV.
Preliminary analysis from FOT engineers shows that three partial
scan anomalies occurred in the suspect area during this test. In
planning future observations this resultant ST-2 FOV response "map"
will help the FOT to avoid positioning guide stars in the problematic
part of the ST-2 FOV; this, in turn, will increase the net science
return from the mission.
2.3 Science Payload Resets Itself
---------------------------------
In the wee hours of the morning (local time) on 26 Jun the science
payload's main computer reset itself. The cause of this reset was the
execution of a bad payload stored command load, the cause of which was
traced to a bug in some ground software. These particular stored
commands, known as Absolute Time Commands (ATCs), are time-tagged
commands that are loaded and stored on-board; at the appropriate times
the spacecraft computer then autonomously executes these commands.
ATCs have been used since launch in daily operations for the
spacecraft; however, because of various problems, ATCs have not been
used in any sustained manner for the science payload.
The recent HZ 43 calibration observation required that the payload
be reconfigured to a non-nominal state. The following RXJ 1856.5-3754
observation then required that the payload be configured back to its
nominal state; unfortunately, this was scheduled to occur at ~1am
local time. Since UCB operates EUVE only during the day shift (with
autonomous telemetry monitoring and paging of on-call personnel during
the off-shift hours), UCB decided to revive the option of using
payload ATCs to handle this reconfiguration. Such an "operational
test" was deemed reasonable since an ATC failure would only impact
science data return and would pose no health and safety risk to the
payload instruments.
The FOT members built, manually checked, and then loaded the
relevant ATCs onto the spacecraft. Upon ATC execution the payload's
main computer detected problems with the load and "safed" itself by
initiating a software reset, thereby turning off all seven detectors.
Shortly thereafter the ground software detected the reset and paged
FOT members who then responded by coming in to the operations center.
Over the course of next few hours the FOT members reconfigured the
payload back to its nominal science-taking state.
The buggy ground software has since been patched and successful
payload ATC tests have been conducted to verify its proper operation.
In early Jul payload ATCs were then actually used successfully in
operations.
2.4 Ground Software Expanded to Include Automated Spacecraft Monitoring
-----------------------------------------------------------------------
On 18 Jun UCB programmers installed a new version of the payload
ground systems software. The major component to this release was a
major addition to "eworks", the system used operationally since Feb
1995 to autonomously monitor telemetry from the science payload. The
newly expanded and integrated eworks now autonomously monitors both
the payload and spacecraft systems.
Eworks began to detect "anomalies" almost immediately; some were
real and some were not (e.g., due to incorrect limit settings in the
eworks knowledge base). Over the course of the next few weeks FOT
members reviewed these eworks detections and, with the help from UCB
programmers, revised the relevant rules where appropriate.
Overall, the eworks system is performing very well. It has
consistently detected eworks spacecraft rule violations for various
engineering monitors, including those related to the spacecraft power
systems, tape recorders, on-board telemetry monitors (TMONs), and even
an equipment problem at GSFC that resulted in an extended data outage
at UCB. The FOT continues to refine the eworks performance and adjust
its engineering knowledge base on an on-going basis.
2.5 On-Line Access to EUVE
--------------------------
Listed below are the various methods for on-line access to EUVE:
o UCB/CEA World Wide Web (WWW) at URL: http://www.cea.berkeley.edu/
o anonymous FTP: ftp.cea.berkeley.edu
o EUVE Electronic Newsletters
Past issues -- available via the UCB/CEA WWW site
Subscriptions -- mail majordomo@cea.berkeley.edu ("subscribe
euvenews")
Post message (moderated) to all subscribers:
mail euvenews@cea.berkeley.edu
o GI Program
Are you interested in finding out about or using EUVE data? Do
you need help in understanding EUVE data sets? Do you need help
in using the available EUVE data analysis software tools? If you
answer "yes" to any of the above, the Guest Investigator (GI)
Program at UCB/CEA can help YOU! For more information see the
UCB/CEA WWW site or contact the Archive
(archive@cea.berkeley.edu).
o Public RAP
The Public Right Angle Program (RAP) is a simple and easy method
for researchers to propose for long-exposure EUVE imaging data.
For more information on the Public RAP and the simple proposal
process see the UCB/CEA WWW site (address below) or contact the
EGO Center (egoinfo@cea.berkeley.edu). Mail all proposals to
euverap@cea.berkeley.edu.
o Contact information for the EUVE Science Archive or EGO Center:
Center for EUV Astrophysics
2150 Kittredge St.
Berkeley, CA 94720-5030
510-642-3032 (voice)
510-643-5660 (fax)
archive@cea.berkeley.edu
egoinfo@cea.berkeley.edu
3. EUVE Outsourced Extended Mission Status Report
=================================================
by Brett Stroozas, EUVE Mission/Flight Director
Work continues to clean up the remaining open issues from the
outsourcing of EUVE Explorer Platform (EP) spacecraft operations from
GSFC to UCB/CEA. The following sections describe some of the
outsourcing highlights from Jun 1997.
3.1 New TPOCC Software Release Delivered
----------------------------------------
On 5 Jun the GSFC TPOCC development team delivered a new EUVE TPOCC
software release to UCB, who installed it that same day on the backup
TPOCC equipment string. UCB commenced testing of this new software
immediately. This release contains a number of improvements,
including a significant increase in the commanding rate, and is
performing well overall. The TPOCC development team continues to work
on fixing the remaining bugs for a final GSFC-funded software release,
which is scheduled to be delivered to UCB in Sep.
3.2 Progress on PACOR Replacement
---------------------------------
Since launch science data has been routed to UCB from GSFC's Packet
Processor (PACOR) facility. One component of UCB's outsourcing
proposal was to take over the PACOR functions at UCB. UCB has written
some prototype software that successfully accesses both realtime and
tape recorder playback data. Over the course of the next few months
UCB programmers will complete the software development and testing
before the FOT begins using it in operations. The current schedule
has UCB assuming full PACOR functions by 1 Oct.
--------------------------------------------------------------------------
The EUVE Electronic Newsletter is issued by the Center for Extreme
Ultraviolet Astrophysics, University of California, Berkeley, CA
94720, USA. The opinions expressed are those of the authors. EUVE
Principal Investigators and Newsletter Publishers: Dr. Roger F.
Malina and Professor Stuart Bowyer. EUVE Newsletter Editor: Brett
Stroozas. Funded by NASA/UCB Cooperative Agreement NCC5-138. Send
newsletter correspondence to ceanews@cea.berkeley.edu.
The EUVE project is managed for NASA by UCB: Dr. Roger F. Malina,
EUVE Observatory Director; Dr. John Vallerga, EUVE Observatory
Deputy Director; Dr. Mike Gunter, EUVE Project Manager; Mr. Brett
Stroozas, EUVE Mission/Flight Director; Mr. Rob Nevitt, EUVE
Operations Manager. NASA HQ: Dr. Guenter Riegler, Program Manager.
EUVE Science Advisory Board: Dr. Steve Howell, Chair.
END-----------EUVE------------ELECTRONIC---------------NEWS-------------END
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