Title: New Millennium EO1 Advanced Land Imager 23 January 1998
1System Testing forEarth Observing-1
Mark Perry EO-1 Lead Systems Engineer Swales
Aerospace
2Agenda
- System Testing Topics
- Overview of System Tests
- Details of Aliveness Test
- Development of the EO-1 CPT
- Details of Functional Test
- EO-1 CPT Design
- CPT Sections
- Highlights of the First CPT
- Overview of Successful Tests from the First CPT
- Omissions During the First CPT
- Problems During Execution
- Problems during Execution
- Status of System-Level Testing
- Objectives of First CPT
- Summary
3System Testing Topics
- Description of system tests
- Detailed description of comprehensive performance
test - Results of first comprehensive performance test
- Plans for system testing through launch
4Overview of System Tests
- Aliveness
- Verifies that each subsystem and payload
operates, including basic functionality
mechanical motion, (configuration or life time
limited) - Used when system configuration or time
limitations prevents a full functional test - Quick verification of satellite health after a
move - After each axis of vibration
- Prior to acoustics test
- During launch countdown and during countdown
simulations - Functional
- Verify every interface, command, telemetry point,
and function - Uses EGSE as stimulus and to test systems more
fully than aliveness test - Performed after vibration and acoustic tests, and
on the LV
5Overview of System Tests (CONTINUED)
- Comprehensive Performance Test (CPT)
- Measures performance of each subsystem, and EO-1
as a system - Dry-run of the CPT performed at Swales in May
baseline in July - Three other CPTs during thermal-vacuum test,
after environmental tests, and at the launch site - Special tests. These tests need special support
equipment, or are conducted only a single time.
Some FDC tests are special tests. - Some examples of special tests
- RCS high-pressure test (tank has limited
permissible high-pressure cycles) - High/low-voltage test (single-time verification
of function) - Exhaustive command permutation test (not
necessary every CPT) - 1773 SEU test (requires special GSE)
- Inserted into the schedule when procedures and
equipment available
6Details of Aliveness Test
- Every component, subsystem, instrument, and
payload is turned on - Nominal telemetry provides initial
state-of-health verification - Includes imaging and end-to-end data flow which
is extensive test of ALI, Hyperion, AC, WARP, and
X-band - ACS modes and components tested
- All power-system functions tested
- All CDH tasks tested
- All downlink rates tested, S-band and X-band
7Development of the EO-1 CPT
- Based on Spacecraft Test Operating Language
(STOL) Procedures as much as possible - Automatic command verification and limit checking
- Executes quickly
- Can repeat with precision
- Procedures are directly transportable to
operations team - Can check STOL procedures before running first
CPT - Bottoms-up, modular approach
- Using tests developed for box testing and
integration - Some tests also used in aliveness and functional
tests - Each subsystems tests verify all subsystem
functions and requirements. These tests are
listed and cross-referenced to CPT sections. - Where possible, conduct tests of different
subsystems in parallel to shorten the duration of
the CPT - TRMM and XTE CPTs used for reference
8Details of Functional Test
- Same as the CPT with the following exceptions
- Performance-only tests are eliminated, such as
the long (spin-down) RWA test - The launch and B-dot timelines are shortened
- Specialized instrument tests eliminated, because
they are fully tested in a max-data-rate,
end-to-end test - LFSA deployment has a limited number of cycles,
so its test is eliminated - EFF test is shortened to a few cycles
- Multiple-permutation test of s/a release
redundancy eliminated (redundant side still
tested) - Dedicated s/a drive test eliminated, since the
s/a drive is continuously tested in the
background - Orbit tests are eliminated
- The total duration is about 24 hours, instead of
the 48-72 hours needed for the CPT - As in the CPT, much of the system subsystem
health, function, performance is confirmed and
determined from nominal telemetry
9EO-1 CPT Design
- Three general phases with 11 sections
- Begin with a launch, ascent, deployment, and
sun-acquisition simulation to verify the most
critical timelines on the mission and to stress
the power system - Follow with a series of tests to verify all
satellite functions and to measure system
performance - End with several real-time, nominal orbit-cycle
tests - The CPT is designed for ambient testing, with the
solar arrays un-mounted and all the instruments
and payloads integrated - Modified for first CPT (without Hyperion)
- Modified for thermal-vacuum testing (Hyperion
cryocooler operations, PPT firing, and RCS
pressurization will be different) - Modified for launch site (solar arrays will be
mounted) - Data used to begin subsystem trending of key
parameters
10CPT Sections
- CPT0 Launch configuration. The S/C is turned on
configured as for launch. Nominal performance
is verified through telemetry - CPT1 Ascent through sun acquisition. From switch
to internal power, through launch, ascent,
separation, deployment, rate nulling, sun
acquisition following a worst-case timeline. Real
time enables assessment of ACS timers the power
system. During the coast phase, additional
subsystem tests gain experience in operating the
S/C with 2kb/s telemetry. - CPT2 ACS nominal S/C operations. Nominal
configuration, except instruments, payloads,
WARP are off. Timeline driven by ACS tests
phasing, sensor stimulation, actuator operation,
GPS, coupling. Power, S-Band, M5 tests
conducted in parallel. S-Band requires some
dedicated time. - CPT3 Instrument turn-on, including payloads
WARP. Verify health of instrument most
functions excluding imaging.
11CPT Sections (CONTINUED)
- CPT4 Comprehensive instrument payload tests.
Each payload performs exhaustive testing,
including image data, where possible - CPT4A ALI. Dark images, cal lamps, heater
functions, FDC, mechanisms, processor loads,
timers. - CPT4B Hyperion. Dark images, cal lamps, heaters,
cryocooler, mechanism, timers, FDC. - CPT4C AC. Dark images, lab image, gain
variations, temperature control - CPT4D LFSA. Launch release, deploy,
current/voltage - CPT4E PPT. Single multiple firings, both
tubes, long short pulses - CPT4F EFF
- CPT5 Comprehensive ACS testing. Complete
performance testing of ACS S/W component
functions. RCS testing.
12CPT Sections (CONTINUED)
- CPT6 Solar-array drive. Orbit rate, ramp up,
ramp down, open loop test, blind acquisition of
index, min/max travel limits, rewind,
potentiometers, glitch test. - CPT7 WARP/RF. Correct image data through X-Band,
correct data through MSSP to X-Band at 2 Mb/s
(compare X- and S-Band data), correct pointing of
X-Band. - CPT8 End-to-end tests maximum rate. Correct
data from instruments, through WARP X-Band to
ground storage. Test maximum data ingest all
instruments operating at the same time for 60
seconds. - CPT9 Safemode load shed. Transition to
safemode, ACS, all subsystems put into correct
configuration. Safemode recovery - CPT10 Special command. Test each special
command reset processors switch to alternate
PROMs. - CPT11 Orbit-cycles. As a minimum
data-collection orbit with downlink,
lunar-calibration orbit, delta-V orbit.
13Highlights of the First CPT
- The first iteration of the CPT took about 72
hours. Most tests were successful - Tests with the most problems during the first
execution were re-run on the fourth day, with
success. These tests were CPT0, CPT1 (launch),
and some ACS tests from CPT2. - There were 36 problem records (PRs), which
represent hardware or software anomalies. Most
are resolved. - There were about 100 discrepancies in the CPT
procedures, most of which had not been tested
previously. Most of the deviations caused test
delays. Most of the deviations have been
incorporated into new versions of the procedures.
- The FOT developed orbital timelines, which were
tested successfully and resulted in improved
command sequences
14Overview of Successful Tests from the First CPT
- ALI comprehensive Health Safety and imaging
- All WARP functions, performance and evaluation
- Power system solar-array drive, power switching,
and battery-charge management - ACS End-to-end open loop phasing of all major
ACS modes of operation were performed. Completed
a full performance test of RWAs, IRU, MTBs - CDH all thirteen of the M5 CDH tasks performed
without error - GPS update of spacecraft time tested
- Command sequence (ATS and RTS) tested
- RCS thruster valves and flow tested
15Overview of Successful Tests from the First CPT
(CONTINUED)
- Some contingency and FDC tested
- HOP (solar-array release) redundancy and backup
activation - ACS timers to delay transitions
- Transition to safemode
- 1773 redundancy
- Watchdog timers, special commands, and re-starts.
- EFF loaded and executed
16Omissions During the First CPT
- Hyperion, Atmospheric Corrector, LFSA and
Autonomous Star Tracker were not integrated. (AST
I/F and interaction with the ACS was tested
verified.) - Due to ALI concerns, the PPT was not tested
- Most FDC was not tested (exceptions stated above)
- CDH uplink-error tests not performed. (Tested
at box-level.) - RF The S-band RF not tested (GSE Transmitter in
repair RF was tested during integration.) - RF X-band not tested (critical X-band tlm not
calibrated). X-Band passed all performance tests
during integration - Solar-array drive redundant drive and encoder,
orbital-motion control by M5 ACS FSW, including
imaging profile
17Omissions (CONTINUED)
- ACS use of GPS position and velocity vectors
(tested previously during integration) - Since the ACE software is just completing
development, ACE safehold control of the
actuators (MTB, RWA, SAD) not tested - End-to-end phasing for the M5 ACS B-dot control
mode - Thermal thermostatically-controlled heaters will
not draw power unless the temperature is below 4
to 8 Celsius - Since the ACDS required some software patches, we
did not perform some M5-reset tests (for example,
memory-scrub errors), which requires re-loading
the patches. The re-sets were tested during
integration and at the box level. - Comprehensive testing of PSE and CDH commands
Some seldom-used commands not tested
18Problems during Execution
- About 100 procedure deviations. Most of these
have been incorporated, already, into corrected
STOL - TSMs did not operate at first. (TSMs were not
available for testing prior to the CPT). The
launch TSMs were fixed and re-tested. - GPS telemetry had intermittent dropouts, even
after new s/w (PTR ___ ) - The ACE software, version 2.03, contained errors
(2.03 had not been tested prior to the CPT).
After using an earlier version of the code for
about 24 hours, ACE 2.04 was loaded and used
successfully for the remainder of CPT. - The magnetic field around the spacecraft was
different from the previous TAM calibration ALI
integrated and SAS wiring - There is a still-undiagnosed problem using the
AST load box (EGSE) - EFF hogged the M5 CPU for too long and caused a
warm re-start
19Status of System-Level Testing
- Working on STOL procedures
- Finish building tests that were omitted from the
first CPT due to insufficient preparation. - Complete revisions of all existing STOL
procedures - Perform test-run of all new and revised
procedures so that the next CPT executes smoothly - Each subsystem working on improving tests
- Final review of subsystem requirements
- Complete red and yellow limits for parameters
that have limits - Yellow limits are just outside nominal or
expected operation and permit a controlled
response by the TC - Red limits indicate impending damage to flight
hardware and require immediate action - Completed two aliveness tests that were
abbreviated due to missing hardware
20Objectives of First CPT
- Met all objectives of first CPT
- Perform as much functional and performance
testing of EO-1 as is possible - Refine our knowledge of operating EO-1
- Identify problems and additional work necessary
before baseline CPT and environmental tests - Test the CPT STOL procedures
21Summary
- First dry run of CPT was successful, but
incomplete - Successfully tested most of EO-1 but some
omissions due to lack of hardware (AST, Hyperion,
etc.) and problems with GSE (S-band and X-band) - Some testing also reduced due to some incomplete
procedures (redundant s/a drive, etc.) - Demonstrates that smooth CPT can be completed
within 72 hours - Missing procedures are nearly complete
- All components and payloads will be mounted for
the baseline CPT - Nearly all Problem Records have been resolved
only Category C issues remaining - Telemetry filter tables for 2 kb/s downlink rate
- AST interface?
- FEDS crash
- Anomalous warm starts (intermittent problem with
probable causes based on configuration do not
expect during baseline CPT)
22Spacecraft Testing
23Agenda
- Mechanical Alignment
- Vibration Testing
- Shock Testing
- Mass Properties
- Acoustic Testing
24Mechanical Alignment
- Satellite ground alignment plan (SAI-PLAN-206)
establishes system requirements - The following alignment measurements shall be
performed to establish the spacecraft primary
reference frame - S/C MRC to S/C datums
- S/C SRC to MRC
- IRU SRC will be mapped to the S/C MRC star
tracker reference cube - ALI HSA reference cubes will be mapped to the
S/C MRC - ALI ACI Optics Module shall be co-aligned to
within 2 arc-mins. Bushings have been fabricated
to allow adjustment in the position of the ACI OM.
25Mechanical Alignment Flow
- Baseline measurements shall be performed after
all flight components have been installed - Alignment measurements shall be performed of the
IRU and star tracker to S/C MRC prior to
vibration testing. Post vibration measurements
will be made to verify that alignment has been
maintained between components - Measurements are taken with one sec accuracy
theodolites (Model Wild T2) with autocollomating
eyepieces
26Satellite Vibration Testing
- The Delta 7320-10 launch vehicle payload
environment includes sustained sinusoidal
vibration as well as quasi-sine transients during
the launch phase of flight - Three separate and distinct sustained oscillation
conditions typically occur, resulting in both
lateral and thrust-axis responses. These
conditions, in the order they occur in flight,
and the associated frequency bands and sweep
rates are - First pre-MECO (Main Engine Cutoff)25 to 30
Hz1.5 octaves per minute - Second pre-MECO30 to 35 Hz1.5 octaves per
minute - Prior to MECO15 to 20 Hz4 octaves per minute
27Satellite Vibration Testing
- Satellite Sine Vibration Test Plan (SAI-PLAN-307)
has been drafted and is in review by project,
facility spacecraft personnel - The vibration test shall be run in three axes.
The X Y-axis tests shall be run on the lateral
slip table the Z-Axis test shall be run on the
exciter in the vertical configuration with the
use of a head expander - The launch vehicle contractor shall provide a
Test Payload Adapter Fitting for use during this
vibration test - The MAP S/C vibration test fixture is being used
for this test. The fixture assembly consists of
three parts, 1) a force ring plate, 2) six
multidimensional force transducers, 3) adapter
test plate
28Satellite Vibration Testing
- Approx. 30 tri-axial accelerometers have been
identified on the spacecraft and payload. These
accelerometers were installed at the Swales
cleanroom facility, prior to shipment to GSFC - The vibration test control instrumentation will
consist of three tri-axial accelerometers mounted
on the MAP adapter plate. The average in-axis
response of these accelerometers will be used to
control the test - Three additional accelerometers will also be used
to limit the input acceleration level to the
spacecraft, ALI HSA. A predetermined, Not To
Exceed (NTE), level will be specified for each
limiting accelerometer and the test input levels
shall be automatically adjusted, by the control
system, if the NTE level of any of the limiting
accelerometers is reached
29Satellite Vibration Testing
- The following figures shows the proposed
accelerometer placements
30Satellite Vibration Testing
- The test specification is derived from latest
flight coupled loads analysis times a 1.25 factor
to obtain the protoflight levels below - The sweep rates for the sustained oscillations
have been selected to approximate the actual
flight time it takes to sweep through the
frequency bands shown
31Satellite Vibration Testing
- The following plots are expected responses for
the S/C, ALI HSA
ltltlt Response Plots gtgtgt
32Satellite Shock Testing
- The satellite shock test procedure will be
incorporated within the sine vibration test
procedure - Two shock tests will be performed at the
conclusion of the vibration test - The satellite will be lifted, by a crane, approx
3 with the test PAF installed. A sheet of foam
will be placed under the PAF and the clampband
shall be released and allowed to drop onto the
foam sheet - All accelerometer instrumentation used during the
vibration test shall remain installed on the
satellite and will be recorded during the shock
test
33Satellite Mass Properties
- The satellite mass properties test plan,
SAI-PLAN-319, will be created to provide the
facility test requirements - The satellite center of gravity in the X-Y plane
and the moment of inertia about the Z-axis will
be measured and compared to the prediction from
the CAD solid model - This test will be performed prior to vibration
testing and again before acoustic test with a
fully integrated satellite - The test will be preformed on the Miller mass
properties table in building 15 - The satellite will be placed on the thermal
vacuum test fixture with the clampband installed
34Satellite Acoustic Testing
- The maximum acoustic environment for the EO-1
satellite will occur during liftoff and transonic
flight. Liftoff levels are typically higher than
transonic levels at the payload location - A satellite acoustic test plan, SAI-PLAN-320,
will be created to provide the facility test
requirements - This test will be preformed on a fully integrated
satellite in the GSFC acoustic test facility in
Building 10 - A reduced set of accelerometer instrumentation
will be installed and recorded during the test - The satellite will be lifted off the
transportation dolly and raised into the center
of the microphones acoustic field
35Satellite Acoustic Testing
- The predicted EO-1 acoustic environment is a
function of the configuration of the launch pad,
the vehicle (e.g., 7320 Delta with 3 GEM solid
motors), the payload fairing (10-ft. composite,
with 3-in. acoustic blankets) and the fill effect
due to the satellite and DPAF volume and radial
gap to the fairing wall - The EO-1 protoflight acoustic levels are shown.
The test duration is one minute for protoflight
test. These estimated P95/50 probability levels
are based on current McDonnell Douglas Aerospace
Delta 7320-10 levels, with an adjustment for the
EO-1 fill effect