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Archive for April, 2006

28-Apr-06 | Delta flight 314 – CALIPSO / CloudSat

It was lucky number seven for Delta 314 this morning, as it delivered CALIPSO and CloudSat into orbit. After six previous scrubs, the two-stage Delta II rocket leapt from the pad at Vandenberg’s SLC-2W at an official liftoff time of 03:02:16.721 PDT and quickly vanished into a low-lying cloud bank. Infrared tracking cameras provided the only view of the remainder of the flight, their steady aim showing clearly the jettison of its 4 booster motors, MECO, first/second staging, second stage ignition, and payload fairing jettison. The “Big Crow” tracking aircraft, whose lack of refuelling support caused two scrubs earlier in the week, lost its telemetry lock with the Delta rocket and was unable to provide realtime data during the one significant event it was slated to cover, SECO-1. Unseen or not, the vehicle completed all its remaining tasks and deployed CALIPSO (at T+62:31) and CloudSat (at T+97:37) into their sun-synchronous delivery orbits. Over the next six weeks the satellites will be checked out and moved into their operational orbits, where they will join the “A-Train” — a fleet of Earth-observing satellites, moving in close formation in similar orbits, that includes Aqua (Delta 291) and Aura (Delta 306). Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), jointly operated by NASA and CNES, will provide a global map of atmospheric aerosol particles. CloudSat will study the formation and function of clouds, answering some basic questions about how they generate rain and snow, to improve the science of climatology.

27-Apr-06 | Still ready to go

Boeing engineers have given the Delta II rocket a clean bill of health, stating that "unusual temperature sensor readings observed during the previous two launch attempts were primarily the result of higher temperature  pressurization rates and are not indicative of any defect in the sensor. The sensor does not require replacement and can fly as is." Another launch attempt is set for Friday morning at 10:02 UTC, with the weather forecast showing some ground fog and low visibility but nevertheless acceptable conditions.

26-Apr-06 | Scrubs 5 and 6

An attempt to launch CALIPSO and CloudSat on Thursday morning has already been scrubbed for the sixth time, due to a problem with a nitrogen sensor on the second stage of the Delta II rocket. The launch will now occur no earlier than Friday morning, pending resolution of the sensor issue. Earlier today, a dismal weather picture — thick clouds, high winds, and rain — led to the fifth scrub in six days for the dual payloads.

25-Apr-06 | Winds (4th scrub)

Tuesday morning brings the fourth scrub, this time for upper level winds being out of limits. A 24-hour turnaround is in work.

23-Apr-06 | Scrubbed for the third time

Sunday morning, and the third scrub in a row for CALIPSO/CloudSat, again due to problems with the refuelling aircraft.

22-Apr-06 | Scrubbed again

CALIPSO/CloudSat has been postponed until Sunday, 23 April. A refuelling plane needed to support a mobile telemetry aircraft over the Pacific Ocean was unavailable for a Saturday launch. The instantaneous window remains at 10:02 UTC.

21-Apr-06 | Launch scrubbed

Launch of the NASA-led dual missions of CALIPSO and CloudSat was scrubbed this morning with 48 seconds to go in the countdown.  Spaceflight Now’s Mission Status Center quickly reported a momentary loss of communication between the CALIPSO spacecraft and its ground support network at CNES in Toulouse, France, while a NASA Media Advisory later in the day stated the loss was of primary and backup phone lines between France and the Mission Directors Center at Vanderberg.  In any case, the drop-out meant a fateful call of “hold – hold – hold,” and with only an instantaneous launch window there was no time to reset to the T-minus four minute mark. Controllers expect to understand the comm glitch today, and are working toward another attempt tomorrow morning, Saturday, 22 April.

01-Apr-06 | LRO outgrows Delta

NASA’s Lunar Reconnaissance Orbiter, heading for the Moon in 2008, will do so on an EELV (either Atlas V or Delta IV) rather than a three-stage Delta II 7925 as originally planned. Associate Administrator Scott Horowitz was quoted as saying the change was made “to avoid stability problems with [Delta II’s] spinning second stage, growing out of the heavy fuel load needed to get to the Moon.” Note that it is in fact Delta’s solid-fuelled third stage that requires spin stabilization. In any case, the increased payload capacity of an EELV means LRO may receive an upgraded sensor package, or perhaps even an impactor probe. (Lunar Enterprise Daily, 13-Jan-06)

     

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