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Title:  Operations & Launch
Background      Status Log    Launch Activity Timeline     Contact

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Click here for a replay of the Delta II EO-1/SAC-C launch on November 21, 2000 from VAFB.

Click here for a 2.5MB Quicktime movie describing EO-1. (2:12 secs)

Picture of Launch
EO-1 / SAC-C launched from a Boeing Delta II Rocket at Vandenberg Air Force Base on Tues, Nov. 21st
Photo: William G. Hartenstein.
Sub-Title:  Background
EO-1 Spacecraft with Solar Array Open EO-1 was launched on a Delta 7320-10 from Vandenberg Air Force Base on November 21, 2000. After deployment from the second stage of the Delta, EO-1 flew in a 705 km circular, sun-synchronous orbit at a 98.7 degree inclination. This orbit allowed EO-1 to match, within one minute,
the Landsat 7 orbit and collect identical images for later comparison on the ground.
Vehicle Configuration Overview

EO-1 / SAC-C Boost Profile        EO-1 / SAC-C Orbit Injection Profile
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Sub-Title: Launch Status Log

Entries ceased after May 2001 with calibration and perofrmance scenes for all three instruments being fully collected. Also, with the exception of the Pulsed Plasma Thruster (PPT), all of the technologies have been demonstrated. The PPT will be activated for demonstration purposes following completion of the baseline science validation mission.


EO-1 continues to operate nominally and collect images, averaging around five to six per day in support of the Science Validation Team. Validation of the other technologies continues to proceed nominally. An EO-1 Technology Validation and Infusion Workshop is scheduled for August 15-16, 2001in the Washington, D.C. area.


EO-1 successfully performed its first autonomous formation flying maneuver on May 17th utilizing the GSFC developed Folta/Quinn formation flying algorithm. The maneuver planned and executed on board the spacecraft was performed to maintain a one minute separation and allow both missions to image the same ground for cross comparison purposes.  

An excellent article in "Aviation Week & Space Technology" has been published on this NASA first. After a few more burns using the GSFC algorithm the EFF algorithm will then be switched to utilize a formation flying algorithm developed by JPL (June/July 2001 timeframe).

May 2001:

EO-1 continues to function nominally. On April 23, 2001, EO-1 took its 1,000th data collection event (image). During late March and April, some special calibration scenes of deep space targets (Jupiter, Venus, Pleades) were collected to help assess spectral and spatial performance of the instruments. At this time, calibration and performance scenes for all three instruments have been fully collected. Preliminary results of the analyses on the scenes presented at the EO-1 Instrument and Science Validation Team meeting in Tuscon, Arizona on May 1-2, 2001, indicate that all three instruments are performing as specified.

The combined EO-1 Instrument and Science Validation Team meeting in Tuscon, Arizona was very successful in presenting the instrument calibration results to date and in the transition of detailed information regarding image quality and image artifacts to the SVT members before they fully engage in analyzing their collected scenes. Some preliminary results from the SVT and from the successful Argentina and Austrailian field compaigns were also presented at the meeting.

The emphasis for the next few months will be on collecting the necessary validation scenes for the Science Validation Team (SVT) (80 plus members) which is chartered with ensuring that EO-1 capabilities can demonstrate the same or better science results as Landsat-7. Tasking for EO-1 during this busy North American growing season is almost fully occupied attempting to satisfy the SVT requests.

The prime mission of supporting technology and science validation are fully occupying the EO-1 team at this time. However, there continues to be detailed discussions concerning EO-1 data policy and outside tasking. It is anticipated that these issues will be resolved in the upcoming weeks and publicized via this web site.

March 2001:

EO-1 continues to perform nominally collecting on average 50 calibration (lunar, solar, earth limb scans) and ground images weekly. The field campaigns in Australia and Argentina are winding down as are the ground data collections required for instrument performance. At this time, the majority of scene requests are being performed for the benefit of Science Validation Team selected from the NASA Research Announcement last year. Their goal will be to fully validate EO-1 with paired scenes from Landsat to determine if the ALI, Hyperion and LAC can meet future science research and application objectives.

A significant number of requests have been coming to the EO-1 Mission Technologist and Mission Scientist for tasking of EO-1 (imaging) or for acquiring image data already collected EO-1. The EO-1 project will, in the next two to three weeks, be discussing with NASA Headquarters how this may be accomplished and publishing on this website a process and the criteria for soliciting and selecting requests. Whether these requests can be accommodated in the current 11 month EO-1 mission lifetime or will need to be extended beyond that time frame is still a question to be answered. The EO-1 project wishes to thank the many requesters for their patience and promise more solid answers by the end of March.


EO-1 continues to operate nominally and has taken over 350 images (included calibrations) since launch. The X-band downlink problems experienced in December and early January were all traced to either misconfiguration or equipment problems at the ground stations. Since mid January we have achieved almost perfect downlink results demonstrating that the X-band Phased Array Antenna is operating as specified. Also, the software patch to bypass the Hyperion cryocooler sensor failure has been uploaded to the spacecraft and is working well. This patch will allow the SWIR on Hyperion to operate at a greater duty cycle (80% vs 50% on time).

We continue in February to support the Argentina and Australian field campaigns and complete collection of key sites needed to fully characterize the performance of the three imaging instruments. The Enhanced Formation Flying Software has been working well planning maneuvers to maintain EO-1 within the 1 minute long track and 3 km cross track envelope. At this point we are just monitoring these on-board generated flight navigation "burns" but will begin in later February to allow the on-board system to plan and execute the "burns" with ground approval.


EO-1 has taken approximately 300 images from its three instruments since launch on Nov 21st. Previously reported problems with X-band down-links were traced primarily to problems with ground station configuration or ground station equipment problems. These problems have been resolved for the most part, and we have been obtaining excellent X-band downlinks from the X-band phased array antenna since the early part of January.

Currently, EO-1 is supporting campaigns in Argentina and Australia to fully calibrate the ALI, AC and Hyperion instruments. As part of this campaign, flights of EO-1 with the AVIRIS instrument are underway in Argentina. Field teams in both Argentina and Australia have been deployed to special sites to support ground truth of the sites and atmospheric measurement during the times EO-1 overpasses. Currently, about 75 percent of those scenes required to complete instrument characterization have been collected.

Overall, the EO-1 spacecraft and its instruments have been performing nominally with one exception. A feedback sensor on the Hyperion cryo-cooler failed on Jan 10th. The TRW team that built the instrument have instituted a contingency plan which allows the cryo-ccoler to operate, but with more manual operations. This has limited the on time of the cooler to about one half the scenes over the last three weeks from about a 80% percent on-time earlier in the month. Only the Hyperion SWIR scenes have been effected (only when the cryo-cooler is on is SWIR data valid). A on-board software patch to bypass the sensor is being tested this week which should allow us to return to the greater on-time duty cycle.


Many members of the EO-1 Technology and Science Team have been receiving inquiries about instrument specifications, performance and availability of imagery. A forum will be held on January 11, 2001 in Reston, Virginia at USGS which should answer most or all of these inquiries. Visit our EO-1 Technology Transfer and Infusion page for more details. Please contact the listed web sites to register.

The EO-1 Observatory continues to operate nominally. EO-1 is in formation with Landsat 7 and is currently taking about 6 to 8 concurrent images a day from its three instruments. All three instruments are performing nominally. Some problems still exist in obtaining completely trouble free X-band downlinks of the image data. Although there has been no impact to imaging operations (a current work-around is to schedule additional X-band contacts), a Tiger Team has been formed to better understand these problems. Instrument characterization continues on schedule with the full transition to the Science Validation Team still scheduled for the end of January. Overall, the imaging and spacecraft technologies are operating as planned and EO-1 is delivering excellent technology results.


EO-1 continues to perform nominally. On Friday 12/15, the last two Delta V burns were performed to achieve formation flying with Landsat 7. Over the last week or so we had imaged about 4 to 5 scenes per day. The primary objective in taking these initial images was for calibration and performance measurement of the 3 imaging instruments. As of December 21st, about 75 images have been collected with at least one image from each continent. Validation of the other technologies (Carbon Carbon Radiator, XPAA, LFSA) is ongoing and all are technologies are performing nominally.

Over the holiday period (Dec 23-Jan 2), EO-1 will continue to take about 4 to 5 images per day, again with emphasis on ground sites which can greatly aid in determining the performance of the 3 instruments with respect to Landsat 7. Additionally, next year we will begin the initial testing of the Enhanced Formation Flying on-board navigation software which will eventually provide for autonomous formation flying with Landsat 7.

The EO-1 team wishes to thank all its readers for their interest in this mission and wishes everyone a very happy and safe holiday season. The next status message will come after the New Year holiday.


The EO-1 Spacecraft and Instrument continue to perform nominally this week. Over the last week, we have taken about 17 images over 6 continents using concurrent imaging from all three instruments. Downlinks via the X-band communication system have been successful in downlinking all images to the ground stations. However, there have been a significant number of passes with poor quality. During this week, the Communication Team performed a number of ground station and spacecraft tests to better characterize the X-band downlinks. These activities should increase downlink success rate significantly next week.

This week, the Attitude Control Subsystem team continued to perform tests to better characterize spacecraft attitude knowledge and improve spacecraft stability and pointing performance during imaging. Also, on Tuesday and Thursday respectively, we performed the first solar calibrations for the Hyperion and LEISA Atmospheric Corrector. This data will be very useful in calibrating the spectral resolution of earth images for these two instruments.

Today, we are performing the full turn on of the Hyperion Cryocooler which will cool the Hyperion focal plan to the correct operating temperature to allow for Shortwave Infrared (SWIR) imaging to commence starting tonight. Up to this point only the more visible portion of the spectrum has been valid for images from Hyperion. On Saturday and Sunday we will be performing two Delta V burns which will bring us by Tuesday in full formation flying with Landsat 7. Also this week, we turned on the Pulse Plasma Thruster briefly to verify it survived the launch stress. It will be fully tested in October 2001 after the primary mission is complete.

Starting next week, we will gradually be increasing imaging to at least 4 scenes per day as we progress into more nominal operations.

A press release with first images from EO-1 is scheduled for Dec 18th or 19th. See the NASA homepage for more details.


Over the last three days we have been very busy. On Monday afternoon we took our first test Hyperion image which is being analyzed by the Hyperion team. On Tuesday we performed a major delta v burn to continue our approach to formation flying with Landsat 7. On Wednesday we performed a checkout of the Hyperion cryo-cooler which functioned nominally. Thursday was again devoted to another delta v maneuver while today is dedicated to taking the first two engineering scenes which involve simultaneous imaging of all three instruments. We expect to receive tape data with these two scenes by Monday, Dec 4. The rest of this weekend we will be similarly taking test engineering images from all three instruments and relaying them to the ground stations via X-band playbacks from the WARP. Additionally, the LFSA was deployed successfully on Wednesday.


A lot of activity occurred over the last two days. On Saturday the Advanced Land Imager was activated and we took the first engineering images which have been downlinked to the ground for analysis. On Sunday, EO-1 first major inclination delta v burn took place which will begin the move towards formation flying with Landsat 7. On Sunday evening the Atmospheric Corrector was turned on and a engineering image was taken and downlinked to the ground. All indications are that both engineering images show the instruments working nominally. Today, we are in the process of activating the Hyperion instrument and will be taking an engineering test image later this evening.


EO-1 successfully completed its first delta v calibration burn yesterday and activated two of its major technologies. The Wideband Advanced Recorder Processor used to record, store and provide high rate downlink of the EO-1 instrument data was successfully brought on line and tested with the other major communication technology the X-band Phased Array Antenna. Yesterday morning the Enhanced Formation Flying software was initiated and began running on the S/C processor successfully. Once we achieve initial formation flying with Landsat 7 (around Dec 15) it will be used to maintain the orbits of EO-1 with respect to Landsat autonomously. Today (11/25) we will be activating the Advanced Land Imager and taking initial engineering test images.


EO-1 is now pointing its instruments at the Earth and successfully completed yesterday a critical test of its safehold mode logic which is used to safe the spacecraft in case of problems onboard or errant operations or commands. We are testing the ability of the spacecraft to slew or maneuver in all three axis (roll, pitch and yaw). This should be completed by early evening. This evening we will put the Enhanced Formation Flying (EFF) software in monitor mode to see if it is properly calculating navigation information. Overtime, confidence in the EFF software will lead to EO-1 performing autonomous navigation maneuvers to maintain its formation flying with Landsat 7 tomorrow, EO-1 will test its first propulsion system burn (a sec test burn) in preparation for manuevers over the next 2 weeks to get into initial formaiton flying with Landsat 7.

11/22/00: The Delta II Launch occurred Nov. 21st at 1:24:25 p.m.. EST and brought EO-1 into orbit within 400 to 600m of predictions.

EO-1 separated from the Boeing Dual Payload Attached Fairing one hour after launch and the solar array deployed within three minutes of separation. Despinning of the spacecraft (expected due to off center, center of mass) occurred within one hour of separation and we were in sun acquisition mode approximately 1 hour and 30 minutes after launch with our Solar Array tracking the sun. We are getting expected power from array and all subsystems are functioning nominally.

In the early evening the EO-1 Star Tracker, which is needed to allow EO-1 to point the imaging instruments toward targets on the earth was activated and functioned flawlessly acquiring its guide stars. The GPS subsystem which will be used for navigation and support the formation flying with Landsat was also activated and quickly locked onto the constellation and is providing time and navigation information. This navigation information will be used after earth pointing mode is achieved later tomorrow.

Overall all major objectives were achieved on schedule. Later tonight some additional higher data rate testing with TDRS will be conducted as well as checking of the Hyperion cover (to make sure it is closed). Tomorrow, 11/22 a Safe Hold Mode test will be conducted and the spacecraft will then be put into earth pointing mode (early evening) which it will stay for most of the mission.

Ground station support from the TDRS, Norway, McMurdo Alaska and Wallops ground stations have been superb and throughout the day and evening.
11/21/00: (3:30 p.m. EST) EO-1 was successfully launched today, Tuesday, November 21st at 1:24 p.m. EST. Solar Array was also successfully deployed and everything is running nominally.

(8:30 a.m. EST) Launch Readiness Review was successful yesterday. Preparation continues for launch today, Tuesday, November 21st at 1:24 p.m. EST.
11/20/00: Preparation continues for launch tomorrow, Tuesday, November 21st at 1:24 p.m. EST. Press Conference on NASA TV at 2:00 p.m. EST.

11/19/00: RIFCA Review completed and approved. First launch attempt is scheduled for Tuesday, November 21, 2000 at 10:24 a.m. PST -- (1:24 p.m. EST). EO-1 powerup for the Spacecraft is schedule for Monday evening, November 20, 2000 at (10:00 p.m. EST). Launch vehicle fueling is underway this morning.
11/18/00: Review of RIFCA paperwork continues. Therefore, launch is scheduled for no earlier than Tuesday, November 21, 2000 at 10:24 a.m. PST (1:24 p.m. EST).

11/17/00: EO-1Post fairing aliveness test was run successfully last night, however final closeout issues with the Delta II Launch Vehicle has postponed fueling and moved the launch one day to no earlier than Monday, November 20 at 10:24 a.m. PST (1:24 p.m. EST).
11/16/00: Reinstallation of the fairing and fairing closeouts should be completed by late afternoon. The EO-1 Post-Fairing Aliveness Test should commence at 7:00 p.m. EST. First attempt for launch is holding for Sunday, November 19th at 1:24 p.m. EST.
11/15/00: Due to a gasket fitting problem between the fairing and first stage on the launch vehicle, the Post-Fairing Aliveness Test was postponed until late afternoon 11/16 at the earliest. Therefore, the launch is delayed to Sunday, November 19th.
11/14/00: A Post-Fairing EO-1 Aliveness Test is scheduled for today at 3:30 - 7:30 p.m. EST along with the Flight Readiness Review. Pending success of this last aliveness test, all systems should be "GO" for launch on Saturday, November 18th.
11/13/00: Fairing installation is scheduled for today.
11/12/00: Day off for Boeing, EO-1, and SAC-C.
11/10-11/00: All final instrument inspections were completed as well as final Red Tag Items were removed in preparation for Launch Vehicle Fairing Installation on Monday, November 13th.
11/09/00: Successfully completed last Pre-Launch Simulation Rehearsal. Continuing on with Launch Vehicle Stray Voltage Test.
11/08/00: Final EO-1 Functional Test conducted successfully. This evening the Spacecraft will again be powered on at 11:00 p.m. and the last Pre-Launch Simulation Rehearsal will take place. This test will conclude with the simulated launch at 1:24 EST on Thursday. Additional testing will follow the Pre-launch Sim on Thurday afternoon.
11/07/00: EO-1 Functional Test commenced at 11:55 p.m. and will run through noon EST on Wednesday.
11/06/00: Final battery charging completed on EO-1; continued to checkout all required Ground Support equipment in preparation for Tuesday evening's final EO-1 Functional Test.
11/05/00: EO-1 and SAC-C were transported from the Astrotech facility and integrated onto the Delta launch vehicle. Final mechanical and electrical integration underway in preparation for the Functional Test starting on Tuesday, 11/7/00.
11/03/00: NASA News Media Briefing on EO-1/SAC-C mission. The briefing will be carried live on NASA TV, Channel 8, at 11:00 a.m. EST. It will be replayed again at 1:00 p.m. and 7:00 p.m. EST.
11/02/00: EO-1 and SAC-C (currently at Vandenberg Air Force Base) were integrated onto Boeing's dual payload adaptor assembly.
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Sub-Title: Pre-Launch and L&EO Activity Timeline

L-12 Hrs:Final test of spacecraft and instruments
Day 1:Launch Day! Separation (L+1hr), Detumble, Solar Array Deployment, Sun Acquisition Mode. Power on Star Tracker and GPS.
Day 2:Safehold Mode Test, Earth Acquisition Mode, Roll, Pitch, Yaw Calibration Slews.
Day 3:Engineering Test Burn (Delta V).
Day 4:Turn on and test XPAA and WARP with ground stations.
Day 5:ALI activation. Take first ALI images.
Day 6:Complete ALI turn on. Delta V burn if needed. Activate and take first LAC images.
Day 7:Begin Hyperion activation.
Day 8:Complete Hyperion activation and first images.
Day 9:Contingency Day.
Day 10:Concurrent all instrument imaging starts. Deploy LFSA.
Day 11-20:Delta V burns to begin formation flying with Landsat, Alignment images, concurrent images, ground station verification, first instrument solar calibrations, PPT aliveness test.
Day 21:Hyperion Cryocooler turned on.
Day 22:Begin complete nominal operations.

For more detail see:   Day 1-10 Master Timeline   PowerPoint or HTML

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section title: information contacts

Dan Mandl
EO-1 Operations Manager
NASA's Goddard Space Flight Center
Mail Code:490
Phone: (301) 286-4323
Email: Daniel.J.Mandl.1@gsfc.nasa.gov
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