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Flight 158 - March 1
Ariane 5 and Rosetta are back in the launch zone
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The Ariane 5 for Flight 158 is once again in the Spaceport's ELA-3 launch zone, following a minor repair this weekend to the exterior of the vehicle's cryogenic core stage.
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| Ariane 5 has made the trip from its final assembly building to the ELA-3 launch zone twice during the past several days. |
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Ariane 5 was transferred yesterday from the Final Assembly Building to the launch zone for a second time in recent days, enabling Flight 158's liftoff to now be rescheduled for the early hours of tomorrow morning (March 2).
During this weekend, a point-repair was made inside the Final Assembly Building to the external protective layer covering the cryogenic core stage's external surface. The layer provides insulation for the 155 metric tons of cold cryogenic propellant (liquid oxygen/liquid hydrogen) that is loaded into the Ariane 5's core stage.
Ariane 5 was rolled from the ELA-3 launch zone to the Final Assembly Building on Friday, February 27 after a small piece of the thermal insulation (approximately 10 X 15 cm. in size) apparently separated from the core cryogenic stage.
This small break-away of thermal insulation - discovered hours before the scheduled liftoff on February 27 - apparently was a result of temperature changes that occurred with the fueling and de-fueling of Ariane 5's cryogenic stage during operations last week. Ariane 5 originally had been fueled for a launch on February 26, but was then de-fueled after unfavorable winds at altitude over the Spaceport forced a scrub of the liftoff. The core stage was then loaded again with cryogenic propellant in preparation for the second attempt on February 27.
In addition to the point-repair made this weekend, a general inspection of the cryogenic core stage's thermal insulation was carried out, and a supplemental launch readiness review was held to verify the overall readiness of the Ariane 5, along with the Spaceport's launch infrastructure and the downrange tracking stations.
The targeted liftoff time tomorrow morning is now set for one of two specific instances: 44 sec. past 4:17 a.m., or 44 sec. past 4:37 a.m. (local time at the Spaceport in French Guiana). These precise launch times are the result of Rosetta's unusual mission profile, which will place the deep-space probe on an Earth escape trajectory leading to its encounter with Comet Churyumov-Gerasimenko in 2014.
With Ariane 5 back in the ELA-3 launch zone, the attention is now focused on the Spaceport's weather forecast, which calls for potentially unfavorable winds at altitude during the launch period tomorrow morning. The upper level winds are part of safety factors that are go/no-decisions in the countdown, and were the reason for the first launch scrub on February 26.
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See our Press Release which announces the new launch date.
Additional information on Flight 158 is available in the official Arianespace Launch Kit.
Our previous Mission Update entries enable you to review the earlier mission activity.
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