Ariane launch scrubbed again – ST-5 delay

by Chris Bergin

Arianespace have scrubbed their second attempt tonight to launch their Ariane 5 ECA – carrying the dual payload of the Spanish Government’s Spainsat and Eutelsat’s Hotbird 7A – due a problem with the telemetry circuit of the Hot Bird 7A satellite.

Meanwhile, NASA’s ST-5 (Space Technology 5) mission – due to launch on an Orbital Sciences Pegasus XL rocket from Vandenberg Air Force base – has been delayed to a NET (No Earlier Than) launch date of March 11, to allow for a review of data from the spacecraft’s separation system.

SPACEFLIGHT L2 – click image for details.

Problems with the ground support system at the European Space Agency (ESA) spaceport at Kourou in French Guiana, led to the first delay on Tuesday. Sources claim the issue was a propellant feedline valve – which has now been replaced.

Arianespace has resumed launch operations, including a series of on-ground verifications, and will announce a new target launch date at the beginning of this week.

Live launch webcast, click image:

**Live launch coverage update thread**

Mission preview:

Due to launch in what would have been a window stretching from 22:11 to 23:21 UTC (5:11pm to 6:21pm Eastern US) from the European Space Agency (ESA) spaceport at Kourou in French Guiana.

Coming off the back of a hugely successful 2005, Arianespace will be marking their 26th launch of their Ariane launcher family, with the 10-ton ECA being the top of their range.

Paris-based Eutelsat is a loyal customer of Arianespace, and their Hotbird 7A will be the 21st satellite to be launched via an Ariane for their company. Eutelsat broadcasts 850 television channels and 550 radio stations to 110 million homes in Europe, the Middle East and North Africa.

The 4.1 tonnes satellite will be a companion to their Hotbird currently in orbit – and will take up an orbital position at 13 degrees East, over Gabon.

Less is known about the 7 ton Spainsat, given it is the first satellite to be launched with the singular purpose of secure communications for the Spanish government, military and security services. It was built by Systems/Loral in Palo Alto, California – and will be operated by the Spanish military operator Hisdesat.

Spainsat consists of 13 X-band transponders, plus one Ka-band transponder – and will be positioned at 30 degrees West, placing it over the Atlantic ocean.


The innovative ST5 mission was due to launch on Feb. 28, but has now suffered two delays in quick succession. Officially NASA has slated the new launch date as NET March 6, but sources have indicated this has now been pushed back to March 11.

The ST5 mission is in itself part of an exciting move towards micro-satellites. The benefit of proving the micro-satellite technology works could open up the market for a new range of similar spacecraft, launched on much smaller – and thus cheaper – rockets. Each of the ST5 satellites has all the features of is full-sized cousin.

On this mission, three ST5 satellites – not much larger than a portable television set – will be launched using a Pegasus XL to a near-Earth polar elliptical orbit that will take them to between from 300 kilometres to 4,500 kilometres above the Earth.

Once in orbit, the ST5 micro-satellites will be placed in a row about 40-140 km (about 25-90 miles) apart from each other to perform coordinated multi-point measurements of the Earth’s magnetic field using a highly sensitive miniaturized magnetometer built by University of California, Los Angeles.

This type of measurement is useful for future Sun-Earth Connection missions that will study the effect of solar activity on the Earth’s magnetosphere, a protective magnetic ‘bubble’ that surrounds the planet and helps protect it from harmful space radiation.

The Cold Gas Micro-Thruster (CGMT), built by Marotta Scientific Controls of Montville, New Jersey, will provide propulsion for orbit maintenance. The X-Band Transponder Communication System, built by Aero Astro, will support two-way communications between the ST5 micro-satellites and the ground stations.

***General Space Flight Section***

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