Frye, Stuart W.

NASA Technical Reports Server

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Earth Observing-1 Status 
for the MOWG
on 2 June 2015
Presented by Stuart Frye for 
the EO-1 Team
https://ntrs.nasa.gov/search.jsp?R=20150010994 2019-08-31T08:01:36+00:00Z
EO-1
Honeywell
EO-1 Flight Systems
• Health and Safety of spacecraft (S/C) and subsystems 
continuing nominal operations
• Power Systems are working nominally
– After performing a cycle of VT changes to help condition 
the battery for longer use (improves state of charge, speed 
of charge and differential voltage), the EO-1 VT is now set 
to a VT level of 4.5
• Instruments performing nominally
– Solar and Lunar Calibrations routine including slow scan 
Hyperion and a negative phase angle lunar calibration to 
aid LDCM in calibration
• Out of usable fuel since February 2011 but attitude 
control system (ACS) fully functional 
Earth Observing-1 Status for the MOWG 2
EO-1
Honeywell
EO-1 Mission Enhancements
• The EO-1 mission is out of usable fuel. 
– The spacecraft is no longer tasked to perform MLT 
maintenance burns (inclination burns). 
• With a transition from MOPS (old) to ASPEN (new) 
and CMS (old) to SCP (new) mission planning 
systems, the FOT couldn’t initially perform Delta-V 
maneuvers. 
• The FOT created procedures and implemented a 
way to perform Delta-V maneuvers on the new 
mission planning systems to perform debris 
avoidance maneuvers. 
Earth Observing-1 Status for the MOWG 3
EO-1
Honeywell
EO-1 Mission Enhancements
• EO-1 32K TDRS supports
– EO-1 FOT enhanced the way TDRS passes were used 
previously by adding 32K TDRS supports
• All TDRS supports previously were at a slower 4K RTN rate. 
• With faster 32K RTN TDRS supports, EO-1 passes can downlink 
data much faster compared to the 4K supports.
• EO-1 FOT is working on modifying goal upload logic so that goals 
and sensor-webs can be uploading by ground automation during 
32K TDRS supports thus increasing imaging and house keeping 
capabilities. 
• Requested White Sands to add 32K RTN TDRS related SSC codes in 
SNAS. With dedicated SSC codes, the EO-1 FOT can now quickly 
schedule 32K TDRS supports
– All 32K RTN TDRS related SSC codes have been added for the EO-1 
mission.
Earth Observing-1 Status for the MOWG 4
EO-1
Honeywell
EO-1 Mission Enhancements
• EO-1 Lunar Calibration Modifications
– EO-1 FOT created a way to perform a single scan 
Hyperion centered lunar calibration
• This calibration is performed prior to a positive phase 
nominal 4 scan lunar calibration 
– Singled out all atmospheric corrector (AC) commands 
and reduced the nominal 5 scan positive phase lunar 
calibration to a nominal 4 scan positive phase lunar 
calibration (removed all AC scans/commands).
– Conducted negative phase lunar calibrations in 
conjunction with Landsat Data Continuity Mission 
(LDCM)  
Earth Observing-1 Status for the MOWG 5
EO-1
Honeywell
EO-1 Debris Avoidance Maneuver
• The EO-1 spacecraft had a close approach with a 
(FENGYUN 1C DEB) on 5/10 at 17:57:40 GMT
– Miss distance of ~167m
• The EO-1 FOT team was asked to perform a 10 
second Delta-V maneuver on May 9th at 13:30 
GMT.
– The Burn was successful, the spacecraft thrusters fired 
for the full 10 seconds. 
Earth Observing-1 Status for the MOWG 6
EO-1
Honeywell
EO-1 New Ground Stations
– EO-1 Flight Operations Team (FOT), Earth Observing Systems 
(EOS) Data and Operations System (EDOS), Near Earth 
Networks Services (NENS), Universal Space Network (USN), 
and Wallops and White Sands scheduling personnel worked 
to switch from PF1/PF2 to Northern Alaska ground stations
• testing of S-band uplink/downlink, X-band downlink, and telemetry 
tracking for new ground stations in northern Alaska designated 
USAK-02/03/04
• coordination of firewall rule updates
• conducting test passes over the new ground stations
• implementation of modifications to the ground and flight software 
to point the satellite antenna at the correct locations
• analysis of the command link, telemetry receipt, science data 
capture, and ranging/tracking data files for operational readiness
Earth Observing-1 Status for the MOWG 7
EO-1
Honeywell
EO-1 Recent Anomalies
• Low Voltage Anomaly (concluded)
– The battery was nearly up to full charge by the end of that 
first daylight period and was at 100% 10 minutes before 
the end of the second sunlight period after the anomaly 
– Nominal Lunar Calibrations have been steadily hitting 
lower voltages over the past few years, so after analysis by 
the GSFC Power Branch, it was determined that the TSM 
red low limit could be lowered from 25.5V to 24.75V 
before invoking safehold while still maintaining adequate 
margin
– The FOT prepared and uplinked an update to the relevant 
TSM table on 11 March 2014
– A nominal Lunar Cal at the next full moon was executed 
routinely on 17 March 2014
Earth Observing-1 Status for the MOWG 8
EO-1
Honeywell
EO-1 Orbital Information
• EO-1 Orbit Information on 03/13/15 00:00:00z
– Semi-major Axis = 7065.655 Km
– Eccentricity = 0.000545
– Inclination = 97.936 Deg
– RAAN = 338.705 Deg
– Argument of Perigee = 50.504 Deg
– True Anomaly = 137.525 Deg
– Altitude at Apogee = 691.366 Km
– Altitude at Perigee = 683.669 Km 
Earth Observing-1 Status for the MOWG 9
Earth Observing-1 Inclination Status for the MOWG
10
Honeywell
EO-1
Comparison of March 2013 Senior Review
MLT Projections with March 2015
11
Shows orbital projections have been consistent and 
that earlier predictions were too conservative.
Orbital Projection from March 2013
Senior Review Proposal
Orbital Projection from March 2015
Latest Calculations
This EO-1 MLT and SMA analysis was independently 
verified by the Terra, Aqua, Aura Flight Dynamics team.
August 16, 2016
August 22, 2015
September 29, 2016
• The ALI SNR is inherently 6 to 10X (~800%) that of ETM+. 
• The ALI signal at 8 AM always exceeds 50% of the 10 AM. 
• ALI SNR at 8 AM will be 3 to 5X better than that of ETM+ at 10 AM.
• EO-1 will not reach an 8 AM crossing time until October 2016. 
Crossing Time
at Equator
March 22 June 22 September 22 December 22
Elevation 
(degrees)
cos(SZA)
Elevation 
(degrees)
cos(SZA)
Elevation 
(degrees)
cos(SZA)
Elevation 
(degrees)
cos(SZA)
8:00 AM 28.3 0.47 26.9 0.45 31.8 0.53 27.7 0.46
8:30 AM 35.8 0.58 33.5 0.55 39.3 0.63 34.3 0.56
9:00 AM 43.8 0.69 40.1 0.64 54.3 0.81 40.8 0.65
9:30 AM 50.8 0.77 46.3 0.72 46.8 0.73 47.0 0.73
10:00 AM 58.3 0.85 52.3 0.79 61.8 0.88 52.9 0.80
12:00 PM 88.14 1.00 66.57 0.92 88.17 1.00 66.57 0.92
Signal@8 AM
Signal@10 AM
0.56 0.57 0.60 0.58
ALI data taken at an 8 AM equatorial crossing time
is valuable in spite of the decline in SNR
Signal (i.e. solar irradiance) is a function of the cosine of the solar zenith angle (SZA).
12
EO-1
Honeywell
EO-1 Orbit Plots 5 Year Outlook 
Semi-Major Axis Altitude 
(0.00 = 03 March 2015)
Earth Observing-1 Status for the MOWG 13
EO-1
Honeywell
EO-1 Orbit Plots 5 Year Outlook 
Apogee and Perigee Altitude
(0.00 = 13 March 2015)
Earth Observing-1 Status for the MOWG 14
675
680
685
690
695
700
705
710
715
720
-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90
A
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 A
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 G
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 (
km
)
Latitude (deg)
EO-1 Altitude as a Function of Latitude
(for the first orbit on January 4, 2015)
705 km "Circular" Orbit
EO-1 Descending Orbit
EO-1 Ascending Orbit
15
S N
Descending (Day-time)
N to S
Ascending (Night-time)
S to N
EO-1
Honeywell
EO-1 Ground Systems
• All four Telemetry & Command (T&C) strings working 
nominally
– Successfully performed a contingency test utilizing Backup 
Front End Data System and the 4th String T&C system with 
both ground station and TDRS
• Front End Data Systems primary and backup working 
nominally
• Data Processing primary and backup working 
nominally
• Housekeeping Telemetry Processing primary and 
backup working nominally
Earth Observing-1 Status for the MOWG 16
EO-1
Honeywell
EO-1 Ground Systems
• Flight Dynamics primary and backup workstations 
functioning nominally
– Added TR2 tracking data parameters to allow TR2 
tracking data file (TDF) processing
• Mission Planning primary and backups (both 
ASPEN and ASIST SCP) working nominally
• Central File Hub primary and backup working 
nominally
– Continuing to add more incoming file transfers to the 
Central File Hub, and removing the previous path as 
they are tested successfully
Earth Observing-1 Status for the MOWG 17
EO-1
Honeywell
Future NASA Budget Outlook
• Senior Review Proposal for full operations support 
during Fiscal Year 2014 and 2015 approved by 
NASA Headquarters on 1 July 2013
• Proposed full year of operations during FY2016
with decommissioning starting October 2016 or 
later
• Phase F report version 2 for decommissioning 
management starting October 2016 submitted to 
NASA Headquarters 7 April 2015
Earth Observing-1 Status for the MOWG 18


Earth Observing-1 Status for the MOWG on 2 June 2015

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