Terra Spacecraft On-Orbit Status:
URL: http://www.geocities.com/mtd16.geo/sc_status.html
Terra has completed its first year in orbit!
The Terra spacecraft is operational.
All instruments ares in science mode.
Orbit Parameters:
705 km altitude, 98.2 degrees inclination
Images from the Terra Instruments are now Available!!
Terra Image Gallery on the NASA Terra Site
Terra Image Library on the Earth Observatory's Visible Earth site
Links to Images from the Terra spacecraft
Links to News/Reports on the Terra spacecraft
Weekly Terra status reports
The Terra spacecraft continues to perform well after 1 year in orbit, with almost 10 months at operational altitude.
All instruments are operating and taking science data. While the main goal of the Terra mission is the long term understanding of earth's climate, it has also provided valuable information on specific events, such as fires, flooding, and volcanic eruptions.
A press briefing to discuss initial results from the Terra instruments was conducted on 19 April 2000 at GSFC.
Dr. Yoram Kaufman, Terra Project Scientist at NASA's Goddard Space Flight Center,
presented the results of Terra observations to date and declared the Terra spacecraft "open for business."
Press Release from NASA/Goddard: "Terra Spacecraft Open for Business"
Congratulations to the entire Terra team on achieving operational status!
Initial "first light" images from the Terra instruments have been posted.
Click here for pictures of Terra in its deployed configuration.
Read a recent Florida Today article on Terra
Read a recent Space.com article on Terra
Spacecraft Status:
The EOS Operations Center (EOC) has initiated weekly Terra status reports, which are posted on the NASA Terra site.
A master oscillator (MO) adjustment was performed 12 December 2000.
A drag makup burn was performed 1 December 2000. Performance was nominal.
A MODIS roll manuever is planned for 18 Sep 00. A software patch has been implemented to prevent recurrence of the data formatter problem, which was traced to a resistor network in the instrument. MODIS is currently operating normally in science mode.
The Terra spacecraft successfully supported the Safari 2000 program (18 August - 24 September), which focused on studying the Afican contininent and correlating data from Terra and other spacecraft with airborne and ground-based observations.
The MODIS instrument was restored to science mode on 18 Aug 00 and is producing data while analysis of the formatter anomaly continues.
A serious problem was encountered with the MODIS instrument and MODIS went into in safe mode on 5 Aug 00. It is believed that the problem is with the science formatter on the primary side. The instrument is in low power mode while the anomaly is being investigated. It is anticipated that operations can be resumed using the redundant side once the anomaly is fully understood and corrective actions are taken. MODIS is also currently in an additional outgassing mode in an attempt to preclude further heating of its focal plane, which has gradually increased in temperature unexpectedly.
A drag makeup burn was successfully performed on 2 Aug 00. The burn duration was 31 seconds.
Recent Activities:
A MODIS roll manuever was successfully performed on for 21 July 00.
MOPITT performed calibration activities during the week of 10 July 00.
The spacecraft was manuevered to -17.99, -17.45 and -16.92 degrees in roll orientation on 21 June 00 to allow specific observations by the MODIS instrument. An additional roll manuever was executed on 22 June 00. All manuevers were perfomed as expected. Roll is a rotation of the spacecraft about its longitudinal axis (also roughly about its direction of travel). Click here to see a description of spacecraft orientation.
All instruments continue to perform nominally.
A drag makeup burn was successfully performed on 20 June 00. Spacecraft performance was nominal. The thrusters were fired for approximately 12 seconds.
Two yaw manuevers to facilitate observations with the
CERES instruments were successfully performed on 15 June 00.
A drag makeup burn was successfully performed on 17 May 00. The burn duration was approximately 27 seconds. Spacecraft systems performed as expected. In general, more thruster firing has been required for Terra than originally planned, due to increased solar activity which increases orbital drag on the vehicle.
Activities in optimizing data transmission to the ground and direct broadcasts are continuing, though these are currently working OK.
The first monthly global data maps generated by
CERES have been made available by NASA. You can see them by clicking here.
Following the inclination manuevers, the MODIS Nadir Aperture Door was opened and all instruments were in science mode by 29 April 00.
The second of two inclination burns was performed 28 April 00. The manuever was successful and the spacecraft is back in normal high-fidelity navigation mode.
The first of two inclination burns was performed 27 April 00. For this manuever, the spacecraft was rotated 90 degrees in yaw and the delta-V thrusters were fired for 320 seconds, after which the spacecraft was rotated back to normal attitude. The manuever was successful.
The MISR goniometer was commanded to "home" position on 27 April 00.
MODIS Yaw Slew manuevers were successfully performed on 25 and 26 April 00.
The spacecraft was prepared for several manuevers planned for the week of 24 April 00. The MODIS Nadir Aperture Door was closed and the
CERES instruments were put into contamination safe mode to protect their sensors during thruster firing. The following manuevers are currently planned:
IRU calibration slew manuvers were performed on 13 April 2000. The spacecraft was "rolled" (rotated about its longitudinal axis) +/- 10 degrees and +/- 30 degrees. This was done as planned to provide calibration data for the IRUs (inertia reference units) which measure the orientation of the spacecraft.
A drag makeup burn was successfully performed on 12 April 2000 as scheduled to maintain spacecraft altitude.
Two yaw slew manuevers of +15 and -15 degrees were performed on 16 March 00. The purpose of these slews was to generate data for calibration of the spacecraft's guidance sensors, and consisted of rotating the spacecraft about its yaw axis (the axis which points toward the earth) for a short time, then rotating back to nominal orientation.
The first drag makeup thruster firing since reaching orbit was performed on 14 March 00. The burn duration was approximately 21 seconds, and spacecraft performance was as expected. Drag makeup burns will be performed periodically over the life of the mission and will maintain Terra's orbit, compensating for aerodynamic drag.
As of 8 March 00, all instruments are in science mode. All instruments including MOPITT are collecting science data. MODIS is continuing "bias sweeps", which will allow for precise calibration of its different detectors.
CERES has created a global data map.Other instruments are taking data while continuing calibration activities. The instruments are operating under ATC control, i.e. pre-programmed operation.
The team at the control center watched a real-time X-band direct broadcast of MODIS data down to Goddard on 8 March 00. As the spacecraft passed over the East Coast of the US, we could see the image sweep along the earth as if we we riding on the spacecraft. Typically, instrument data is recorded onboard and replayed later whenthe spacecraft is in contact with a TDRSS satellite, but it is also possible to transmit data directly to ground stations.
A movie of this pass can been seen in the MODIS section of the Terra Image Gallery.
The cryocoolers for the MOPITT instrument were successfully activated on 2 March 00. The coolers chiller the instrument's detectors to crygenic temperatures required for proper operation. Data collection is scheduled to start on Friday.
The earth view and space view covers of the MOPITT instrument were successfully opened on 28 Feb 00. These were the last instrument cover openings, and the Terra spacecraft is now in its fully deployed configuration.
Click here to see a drawing of the MOPITT door opening sequence.
The master oscillator clock was adjusted on 28 Feb 00.
ASTER and MISR imaged the Mayon volcano over the weekend (26-27 Feb).
The
CERES-AFT and CERES-FORE main and MAM covers were opened on 25 Feb 00. This allows the instruments to view the earth, and both instruments are now in flight configuration.
Click here to see a drawing of the CERES door opening sequence.
The ASTER-TIR instrument was transitioned to cooldown mode on 25 Feb 00 in preparation for resuming science mode. The
ASTER team, along with other instrumentors, will be working over the weekend and in particular will be imaging the area of the Mayon volcano, which recently erupted in the Phillipines. This natural event is an unusual opportunity to demonstrate the capabilities of the Terra instruments.
Several important actions were taken on 24 Feb 00 to place the spacecraft bus in its full science configuration. The Navigation system (NAV) was put in its full high precision mode and the GN&C system is using the on-board navigation system (TONS) to control the spacecraft attitude. The solar array was placed in open loop operation, since the spacecraft is now at the correct altitude. All of these systems are working well, and the quality of the first MISR image indicates that the spacecraft is extremely stable.
The
MISR instrument aperture cover was opened on 24 Feb 00. This allows the instrument's scanning mechanism to view the earth, and the instrument is now in its flight configuration. An initial image has been taken; initial quality is better than expected.
Click here to see a drawing of the MODIS and MISR door openings.
The
MODIS instrument nadir aperture door was opened on 24 Feb 00. This allows the instrument's scanning mirror to view the earth, and the instrument is now in its flight configuration. An initial image has been taken and it looks good!
The TIR CPHTS was restarted on 24 Feb 00. It had shut down due to de-prime as a result of the ascent burn on 22 Feb 00. It appears that this CPHTS can respond to the accelerations caused by extended manuevers. The system is now stable and the TIR instrument is scheduled to be put in science mode later today.
The final Ascent burn, #8, was successfully performed on 23 Feb 00. The burn duration was 110 seconds and the spacecraft performance was nominal during and after the burn. Initial review of the telemetry and flight dynamics data looks good. This manuever brought the Terra spacecraft to its operational altitude of 705 km (438 miles), and Terra is flying in formation with the Landsat 7 and Landsat 5 spacecraft.
The successful series of ascent burns is the result of the hard work of the anomaly resolution team and the entire Terra spacecraft team in recovering from the initial burn anomaly on 11 Jan and in executing the plan to bring the spacecraft safely to its proper orbit.
Recent Activities:
Ascent Burn #7 was succesfully performed on 22 Feb 00. The burn was conducted during spacecraft night and had a duration of 280 seconds. Initial review of the telemetry looks good. The last ascent burn of the series is planned for 23 Feb 00, and the burn time will be adjusted based on Flight Dynamics review of Burn #7. This burn will circularize the orbit at the mission altitude of 705 km.
The SWIR instrument was power cycled and and an observation and calibration check was performed on 20 and 21 Feb 00. This was to recover the instrument after indication of anomalous telemetry, which is considered to have been due to a software / configuration problem.
Ascent Burn #6 was performed on 20 Feb 00. The burn time was 320 seconds. Review of the telemetry indicated good performance. The next ascent burn is scheduled for 22 Feb 00.
Ascent Burn #5 was successfully performed at 2152 GMT 18 Feb 00. The burn duration was 320 seconds. This was the first ascent burn performed during spacecraft night (i.e., when the spacecraft is on the dark side of the earth), and required special configuration of the spacecraft to maximize power. The performance of the spacecraft was very good and the telemetry indicated expected performance.
Calibration activities continued through this week with MODIS, CERES and MISR.
Ascent Burn #4 was successfully performed at 1945 GMT 16 Feb 00. The burn time was 320 seconds. Review of the telemetry indicated good performance.
Ascent Burn #3 was successfully perfomed at 2016 GMT 14 Feb 00. The burn time was 300 seconds, and is close to the maximum time that will be used for the remaining ascent burns. Approximately 7 kg of propellant was burned during the manuever. The spacecraft performed very well and the team is happy with the results. Firings will continue on 16 Feb 00 with the first of four 320 second burns.
The
CERES team completed recovery operations for the CERES-FORE instrument on 14 Feb 00. During scanning checkout, an anomalous telemetry indication was received while the scanning head was stopped. The team has determined that this was a false reading and is not indicative of any problem with the instrument. Checkout activities of the CERES-AFT instrument are also continuing.
The first Terra image of the Earth was taken by the ASTER-VNIR instrument! Following this, an initial image was also taken by the ASTER-TIR instrument. These images look good, and the
ASTER team is excited about this preliminary data.
The instruments are in the final stages of activation and most are collecting their first images. All spacecraft systems are performing very well.
Previous Activities:
Ascent Burn #2 was successfully performed at 2043 GMT 12 Feb 00. The burn time was 150 seconds, over twice the longest previous time. Performance of the spacecraft was very good and compared well with predictions. The team is very pleased with the results. Firings will continue on 14 Feb 00 with the first of five 300 second burns.
The first of the planned set of ascent thruster firings was performed at 2115 GMT 10 Feb 00. The "burn" was 60 seconds long and was longest thruster firing since an anomaly occurred on 11 Jan. The burn was successful, and preliminary review of the data indicates good agreement with predictions. The successful burn was the result of the investigation conducted by the anomaly team. As a result of the investigation, the control system has been modified and the firing operation updated to improve performance. The next burn, with a duration of 150 seconds, is planned for 12 Jan 00. This will be followed by a series of 300 second burns every other day, ending on 24 Jan 00. This will bring the SC to its operational altitude of 705 km (438 miles).
The MODIS instrument was put into science mode for calibration activities on 11 Feb 00, including opening of its space view door and opening and closing of its solar diffuser door.
The spacecraft master clock was adjusted on 3 Feb 00 and is now within the requirement of 100 milliseconds relative to Universal Time. This is needed to ensure precise navigation of the spacecraft.
The Solid State Recorder was reconfigured on 3 Feb 00 and is now in normal playback operation.
Two 20 second firings of the thrusters in orbit adjust mode (i.e. raising the orbit) were conducted on 2 Feb 00. The firings incorporated the results of the anomaly team's investigation into the 11 Jan 00 anomaly. Initial review of the data indicates very good agreement with predictions. Several factors are believed to have contributed to the anomaly, including actual center of mass position of the SC and thruster plume impingement on the solar array. Although the forces from the thruster plumes are very small, the array area and its distance from the center of mass can produce significant torques.
The success of these firings is a significant milestone in resolution of the problem. The anomaly team is now working the plan for conducting the firings required to raise the orbit to mission altitude. The tentative burn plan is for ascent burns to resume on 10 Feb and complete by 24 Feb.
MOPITT instrument checkouts were performed 1 Feb 00.
The Solid State Recorder (SSR) was returned to science playback mode on 29 Jan 00, and is working nominally.
The TIR instrument was commanded to cooldown mode on 31 Jan 00, which started its mechanical cooler. The TIR CPHTS (see below) continues to work well.
Additional tests of the delta-V and attitude control (ACS) thrusters were successfully conducted 27 and 28 Jan 00, and verified the health of the primary thruster system. Ascent burns are tentatively planned to resume 1 Feb 00.
The Solid State Recorder (SSR) was successfully restarted on 26 Jan 00.
Checkout of the ASTER-SWIR and ASTER-VNIR pointing mechanisms was successfully performed on 25 Jan 00.
A repeat of the hardware firing of the odd side thrusters was performed on 24 Jan 00. The results were similar to the previous hardware firing and indicate that the thrusters are OK. The thuster anomaly team presented the results of the investigation to date to GSFC management. A plan has been developed for additional firings which will provide data needed for resumption of ascent burns.
The MODIS instrument outgas heaters were turned off and the instrument was put into science mode with the nadir (earth facing) door closed. The blackbody was turned on and calibrations were performed successfully.
Checkout of various mechanisms for the CERES instruments were performed 16-18 Jan 00, as well as checkout of the Sun Presence Sensors (SPS).
The TIR CPHTS was restarted on 19 Jan 00. Reservoir control was switched from A to B side on 24 Jan 00. Since that time, the system temperatures appear to have stabilized in the expected range.
Spacecraft Clock Time was adjusted with good results on 20 Jan 00. The SC was transitioned to Yaw Acquistion mode and returned to normal mode for this activity.
The Solid State Recorder (SSR) halted unexpectedly on 25 Jan 00. Investigation and troubleshooting was performed.
The spacecraft was returned to Spacecraft Control Computer (SCC) control on 13 Jan 00 after being in safe hold since the first ascent burn attempt. The burn anomaly team is continuing to investigate the source of the anomaly and has made substantial progress toward understanding the cause(s). The spacecraft team has been working the problem very hard and is optimistic that
High Gain Antenna (HGA) tracking and communications were restored on 13 Jan 00. An extensive evaluation was made and approval was given to resume normal Ku-band (high data rate) operations. The automatic software patch which restarts the antenna after
The Capillary Pumped Heat Transfer System (CPHTS) for the ASTER-TIR instrument was shut down 15 Jan 00 and is currently under evaluation.
The first engineering burn of the spacecraft propulsion system, where the thrusters will fire for 11 seconds, was conducted 10 Jan 00. The first ascent burn was conducted 11 Jan 00 and was terminated early by computer due to higher than expected roll rate. The spacecraft automatically entered safe mode and stabilized under attitude control electronics (ACE) thruster control. Shortly after, ACE momentum wheel control was restored. An anomaly team continues to investigate the problem and will make recommendations for future activities. Following this, a series of burns will be performed to raise the spacecraft to its operational altitude of 705 km (439 miles).
Investigation of the Propulsion EPC1 has completed and the required actions have been completed. The cause of the anomaly was a failure of 1 of 4 sets of resistors in the load resistor box associated with EPC1.
Checkout of the CERES-AFT and CERES-FORE instrument gimbals was successfully performed 11 Jan 00.
A checkout of the Ku-band high gain antenna radio frequency (RF) link to TDRSS was performed on 05 Jan 00 and excellent RF performance was observed. After completion of this test, HGA operation was suspended due to concerns about effects of the South Atlantic Anomaly (a perturbation in the earth's magnetic field over South America) on the drive electronics, while the investigation into this problem is continuing. It is anticipated that the drive electronics will be automatically shut off via software during transits of the anomaly to preclude further anomalies. The omni antennas (at 1K and 16K) are being used to monitor and control the spacecraft.
The Capillary Pumped Heat Transfer System (CPHTS) for the ASTER-SWIR instrument was activated on 06 Jan 00. This is the second CPHTS to be activated on Terra, and is used to assist in thermal control of the instrument.
The MISR instrument cameras and outgassing heaters were activated on 05 Jan 00.
The MOPITT instrument was switched to standby mode and then returned to safe mode on 05 Jan 00.
A hardware checkout of the propulsion system was performed 4 Jan 00. Each thruster was momentarily fired and all thrusters operated normally. An anomalous response of one propulsion module Electronic Power Converter (EPC) was noted and is being investigated.
The TDRSS On-Board Navigation Software (TONS) was enabled on 4 Jan 00 and is now being used to control the spacecraft.
The MODIS Solar Diffuser Door (SDD) and Nadir Aperture Door (NAD) were unlatched on 04 Jan 00.
The MOPITT instrument was transitioned to safe mode on 4 Jan 00.
The spacecraft and ground control systems were unaffected by the rollover to the year 2000. Spacecraft activation activities were resumed on 01/03/00.
The SCC is running normally with the navigation software (NAV) in normal mode. A software patch has been tested and uploaded to eliminate the recurrence of the error which caused the SCC to shut down during the winter solstice. The SCC1 shutdown (on 22 Dec 99) was due to a numerical error which was found to be due to an unusual alignment of the moon and sun during the winter solstice. Through the diligent efforts of the Flight Operations Team (FOT), particularly the Flight Software group, the cause of the problem was found and corrected.
The MODIS instrument Space View Door (SVD) was unlatched and partially opened to the outgas position and outgassing heaters were turned on (04 Jan 00).
The Capillary Pumped Heat Transfer System (CPHTS) for the MOPITT instrument was activated on 19 Dec 99. This is the first use of a capillary pumped thermal system on a flight spacecraft. At this time, the system is working very well and is being used to maintain the MOPITT instrument at the proper temperature until full instrument activation.
The MISR instrument main cover latch and calibration cover latches were successfully unlatched on 22 Dec 99.
Links to Instrument Sites:
Terra Mission Status Links:
The author of this page is making an effort to make this page the most up-to-date source of information on spacecraft status. Below are other links regarding Terra mission status. Please note that some are not up-date and may contain information which is not completely correct.
Official NASA Mission Status from the Terra web site
Terra Status Reports from the NASA Goddard Web site
Terra Status on 12/30 at SpaceflightNow.com
CNN report on Terra software change
Check out the happenings at the control center, including photos of control team members, at
Try your skills at controlling the Terra spacecraft with
You can see the current position of the Terra spacecraft at
Heavens-Above.com! Check it out!
You can also see a great View of the Earth from Terra by clicking this link and choosing the Terra spacecraft from the list.
Last revised: 18 December 2000
Thank you for your interest in the Terra program!
Please note that the author of this site has completed his assignment on the EOS Terra program. However, he will continue to provide updates of significant events. Thanks to all of you for your kind messages and support. Thanks to Dan Linebarger for providing status from the EOC.
Terra / EOS AM-1 Launch Ops Page
Please click below to see these exciting pictures:
NASA GSFC PAO Terra Site: "First Light" Images
Since these reports give a good summary of each week's activities, further updates to this site will only be made for unusual events.
Thanks for your interest!
Items of Interest:
A MODIS roll manuever was scheduled for 15 December 2000. This manuver is used to point the MODIS instrument so that it can be calibrated using space as a reference.
- MODIS Yaw Manuevers 4/25/00 and 4/26/00 (complete)
- Inclination Change Manuver #1 4/27/00 (complete)
- Inclination Change Manuver #2 4/28/00 (complete)
The MODIS Yaw manuvers will allow the instrument to take calibration data with the spacecraft pointed away from its direction of travel. The inclination manuvers will put the spacecraft closer to the nominal orbit angle and node crossing time. The inclination manuevers are being performed earlier in the mission than originally planned because
launch occurred at the extreme end of the launch window.
Congratulations to the MOPITT instrument team!
Congratulations to the MISR instrument team!
Congratulations to the MODIS instrument team!
Click here to see the MODIS door opening sequence.
Completion of instrument activation, including opening of protective covers, began on 24 Feb 00, and generation of first images is expected shortly.
Congratulations to the Terra team on reaching mission orbit!
Click here to see pictures of the team in the operations center during the ascent burns!
Congratulations to the ASTER team!
History of Terra Orbit Parameters:
Feb 23 2000: 697 km(perigee) x 707 km (apogee), 98.2 degrees (equates to 705 km mission altitude)
Feb 22 2000: 697 km(perigee) x 705 km (apogee), 98.2 degrees
Feb 20 2000: 695 km(perigee) x 697 km (apogee), 98.2 degrees
Feb 18 2000: 687 km(perigee) x 695 km (apogee), 98.2 degrees
Feb 16 2000: 685 km(perigee) x 687 km (apogee), 98.2 degrees
Feb 14 2000: 676 km(perigee) x 685 km (apogee), 98.2 degrees
Feb 12 2000: 665 km(perigee) x 685 km (apogee), 98.2 degrees
(parameters are after burn on day noted)
NASA Goddard Spaceflight Center (outside Washington, D.C.)
by engineers from NASA,
Lockheed Martin, the ASTER, CERES, MISR, MODIS, MOPITT instrument teams, and other contractors.
Please note that this report (from AP)contains a statement that the launch was delayed due to a software glitch on the spacecraft. This is incorrect. The launch delay referred to was due to a launch vehicle software error that shut down the automatic sequencer at T-39 seconds.
Ray Talipsky's TERRA Second Floor - Underground Flight Support Team site
Dan Linebarger's Terra Spacecraft Simulation Site
This simulation gives you a feel for what it is like to control a real spacecraft! (It is harder than it looks!)
Please email me at marc.t.dinardo@lmco.comwith any comments or suggestions.
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