News: Cloudsat Status

CloudSat radar status

Science operations continued nominally in the Daylight-Only Operations Mode. Plans are continuing on a final maneuver that will return the satellite to the A-Train constellation behind CALIPSO on May 15.

On February 3, 2012 the CloudSat Spacecraft was scheduled to perform the first of two planned Semi Major Axis maneuver burns, beginning the return to the A-Train Constellation. During the slew to the delta-v attitude, the star trackers stopped tracking stars. Fault protection determined that there was insufficient sensor data to meet the pointing requirements for a delta-v maneuver and terminated the burn. In fact, the maneuver burn was terminated before it even started and the spacecraft returned to point mode.

The spacecraft performed exactly as designed. While this was disappointing to the team, the spacecraft continued nominal operations and was never in any danger. Power margin on the spacecraft was positive and all other subsystems performed nominally. The spacecraft continued to execute the planned post-maneuver command sequence and returned to the nominal DO-Op mode several orbits later, as expected.

The next opportunity to return to the A-Train will be in June 2012. The spacecraft continues to operate nominally in the DO-Op mode, collecting radar data.

UPDATE: 24 January 2012

CloudSat is planning on re-entering the A-Train constellation beginning February 3, 2012. The first maneuver on 3 FEB 2012 will occur at ~0212 UTC and the second maneuver will occur on 8 FEB 2012 at ~0722 UTC (these times MAY change as we approach these dates). The CloudSat team suggests radio astromony suspend operations during the DAYLIGHT hours ONLY beginning 3 FEB 2012 at 00 UTC. More information will become available after the first manuever is completed. Radio astromony during the nighttime is unaffected by these CloudSat maneuvers.

UPDATE: 23 January 2012

CloudSat continues to fully operate in the Daylight-Only Operation mode (DO-Op) and all issues with the Solid State Recorder (SSR) operation have been resolved.

CloudSat plans on rejoining the A-Train constellation orbit beginning February 3, 2012 to be completed by the end of February.

UPDATE: 3 November

On Tuesday, November 1, the spacecraft was configured for an altitude where by the CPR boresight is offset by 0.16° from Nadir (the pre-anomaly attitude configuration, to minimize clutter in the lower range bins due to surface reflection of the radar signal).

The spacecraft systems performed as expected and the pointing offset has been initially validated. In addition, full-orbit Solid State Recorder (SSR) operations are successfully capturing CPR observations for playback during scheduled downlinks (~7 per day). The CloudSat satellite is now declared fully operational in the Daylight-Only Operations (DO-Op) mode!

On Thursday, October 27, 2011 the CloudSat team successfully turned on the GPS receiver for the first time since April, 2011. We have confirmed in telemetry that, after six months, the GPS receiver is operating nominally.

The GPS allows us to geolocate the spacecraft and timestamp the CPR data appropriately. This is the final piece and a crucial part in producing fully functional science data products.

On Monday, October 24, 2011 the CloudSat team increased the CPR transmit time per orbit from 46 to 52-minutes. The CPR has now been transmitting every orbit in the daylight for nearly two weeks and continues to perform nominally.

On Wednesday, October 26, 2011 the CloudSat team successfully turned on the Non-Essential Bus (NEB) in eclipse. Having reached this critical milestone, CloudSat can now power the GPS, Solid State Recorder (SSR) and star trackers through Earth's umbra.

The CloudSat team has successfully completed our 46 minute/orbit CPR transmit test to improve our understanding of the Flight System thermal characteristics.

The radar continues to perform nominally and all temperatures were within expected ranges.

UPDATE: 14 October

CloudSat has completed the CPR transmit test in which the radar successfully operated in the sunlight for 5 minutes/orbit over a 24 hour period.

At 8:30AM PDT this morning, we increased the operating time to 20 minutes/orbit and telemetry from the first three orbits shows that the radar continues to perform nominally. The 20 minutes/orbit test will continue through the weekend. Data from these tests are being used to study the thermal characteristics of the flight system.

Nominally, we plan to increase the operating time to 46 minutes/orbit beginning Monday, October 17, 2011.

Below is an image from CloudSat during an intentional radar activation on October 12 at approximately 1PM Pacific.

The radar performed nominally and appears to be in good health.

Teams are now working on the implementation of a CPR transmit test in which radar will operate for 5 minutes each orbit over a 24-hour period beginning tomorrow.

The CloudSat team is very excited about the state of the radar and progress made so far in our recovery from the battery anomaly experienced in April 2011.

UPDATE: 7 October

Yesterday afternoon, CloudSat successfully executed an Orbit Lowering Delta-V Maneuver. As planned, telemetry indicated a burn duration of 398.6 seconds for a Delta-V of -1.4 meters/sec. Attitude control was nominal during the burn. Following the maneuver, the spacecraft successfully transitioned back into point standby mode. Analysis of the post-maneuver orbit, indicates that the spacecraft achieved a Delta-V of 1.3965 meters/sec, lowering the semi-major axis by 2.63 km. The CloudSat team is extremely pleased that this maneuver executed as planned, demonstrating the spacecrafts ability to perform maneuvers in advance of returning to a science orbit for the remainder of the mission.

UPDATE: 21 September

The CloudSat radar has not been transmitting since April 17 after suffering a spacecraft battery anomaly. Activities are nominally scheduled to begin the week of 25 September to begin bringing the radar back to operations over the next few weeks. Because of the spacecraft battery issues, CloudSat will no longer be able to operate in eclipse, i.e. when the earth under it is in nighttime.

Although at about the same altitude, CloudSat is no longer part of the A-train of satellites, and hence no longer has the old 16-day repeating orbit. Orbital elements (the so-called TLE) may be downloaded and used as before and the NASA orbital website is still operational. Eventually, CloudSat may return to the A-Train.

The CloudSat radar will be pointed near the nadir, but its pointing may be less stable than prior to the anomaly, although the CloudSat engineers are hoping to eventually fix this and return control to the pre-anomaly level. This means that the cone of avoidance for ground-based radio astronomy is much larger than before, and NASA suggests that radio telescopes cease 94 GHz operations during the daytime until further notice.

Last updated: May 11, 2012.