Atlas 5 WDR complete following leak

by Chris Bergin

The Atlas 5 launch vehicle and its Centaur upper stage – minus its payload – successfully conducted its WDR (Wet Dress Rehearsal) yesterday, despite a helium leak at the launch pad a day previously.

The Atlas 5 (AV-008) is scheduled to launch the ASTRA 1KR broadcasting satellite from Cape Canaveral Air Force Station on April 20th.

Such was the extent of the leak, workers ran out of helium – used to purge the Atlas’ LH2 propulsion system components, so as to ensure the LH2 doesn’t turn water vapour in the air into ice during fuelling.

The fault is believed to be related to the launch pad (SLC-41), specifically a vent valve on one of the Helium Purge panels on the Mobile Launch Platform (MLP) – and areas of the plumbing at the pad.

However, the WDR went ahead as planned and the launch remains on schedule for later this month. It will be conducted by ILS (International Launch Services).


ASTRA 1KR is one of two ASTRA satellites scheduled for launch this year, with ASTRA 1L scheduled for the fourth quarter 2006. Both of the high-powered communications satellites will have a minimum service lives of 15 years.

ASTRA 1KR will join the seven ASTRA satellites currently co-positioned at the prime orbital position 19.2 degrees East, utilising 32 active Ku band transponders in the FSS band, with a TWTA output power of 140 watts and a pan-European footprint. It will operate as a replacement satellite for existing capacity at this position allowing the redeployment of existing resources.

‘It is the first time that SES ASTRA has chosen an Atlas rocket for the launch of a new satellite,’ said Martin Halliwell, Chief Technology Officer of SES ASTRA.

‘Thanks to the great experience that other SES companies have had with Atlas and our own long term relationship with the ILS team, we are confident that the launch of ASTRA 1KR will be successful.’


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