After 3 Scrubs, Digital Control System Launches from Baikonur

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  Space News Business

After 3 Scrubs, Digital Control System Launches from Baikonur

By PETER B. de SELDING
Space News Staff Writer
posted: 24 October 2006
11:59 am ET




PARIS — The Oct. 19 launch of a Soyuz 2-1a rocket from Russia’s Baikonur Cosmodrome in Kazakhstan brought the venerable rocket one step closer to the configuration that will be used when Soyuz launches start occurring at Europe’s Guiana Space Center in late 2008.

The launch of the Metop-1 satellite into polar low Earth orbit was the 1,714th launch of a Soyuz vehicle, including its manned and Molniya versions.

But it was just the second launch of the rocket featuring a new digital control system, including a digital computer and a new inertial measurement unit to improve Soyuz navigation and control.

The first launch of this digital system, which includes a corresponding upgrade of the launch control facilities at the launch pad, occurred in November 2004 from the Plesetsk Cosmodrome in northern Russia. The Plesetsk launch, carrying a Russian government demonstration payload, occurred without a hitch, according to officials from the French-Russian Starsem S.A. joint-venture company that markets Soyuz for customers outside Russia.

But duplicating this system at Baikonur proved surprisingly difficult. Three launch attempts in July were scrubbed at the last minute because of communications difficulties between the upgraded launch control facilities and the Soyuz rocket.

Industry officials said that while Russian authorities urged that the Metop launch team keep trying for a launch in July, Starsem Chief Executive Jean-Yves Le Gall ordered a suspension of the campaign to provide launch officials with time to understand where the glitches were located. Between July and October, Soyuz launch teams tested the new system in multiple configurations and declared that it had been debugged in time for an Oct. 17 launch. But one minute and 10 seconds before liftoff, the automated sequence was shut down by the mission-control computer.

Officials subsequently blamed the launch abort on a false alarm indicating insufficient fuel pressure in the Soyuz upper stage.

In an Oct. 18 interview, Le Gall sought to clarify what happened. In the older Soyuz versions, he said, a series of umbilical lines delivering power to the vehicle before launch all needed to be connected.

But in the Soyuz 2-1a rocket, not all of these connections are needed despite the fact that the lines are still present at the launch pad and the connecting sockets are still present on the Soyuz vehicle.

At least one of these lines should not be plugged into the vehicle. Acting apparently on previous experience, Soyuz ground teams nonetheless plugged in the cable.

As the automated launch sequence started, the Soyuz launch system’s computer registered the unscheduled electrical link as an unacceptable anomaly and ordered a launch abort, Le Gall said.

Soyuz’s on board computer registered the abort order and began draining the upper-stage fuel tank, as it is supposed to do. The first indication that launch controllers had of a problem was the low fuel pressure.

“It was a simple operator error,” Le Gall said. “Apparently it has been more difficult to adapt to this new Soyuz configuration at Baikonur than it was at Plesetsk.”

A launch attempt Oct. 18 was scrubbed because of high winds in the upper atmosphere above the Baikonur site. The launch finally occurred Oct. 19 – six months after the satellite arrived at Baikonur to begin its launch campaign.

The launch featured the first-time use of a 4.1-meter-diameter fairing, a new design that required minor modifications to the launch-pad structure that keeps Soyuz erect on the pad.

A final modification — adding the more-powerful RD-124 engine to the Soyuz third stage — will be needed for the Soyuz 2-1b configuration that also will be used for commercial launches from Europe’s Guiana Space Center.

This version of the vehicle will be used to launch the Corot astronomical satellite owned by the French space agency, CNES. The launch is scheduled for December.