Tag Archives: Fregat

Independent Arianespace investigation cites design error as cause of Russian launch failure

A just released independent investigation by Arianespace of the Soyuz rocket launch failure that put two European Galileo GPS satellites in the wrong orbits has concluded that the design of the Fregat upper stage, not an assembly error, was at fault for the failure.

The upper stage was not oriented correctly because fuel lines to thrusters had become frozen.

The freezing resulted from the proximity of hydrazine and cold helium feed lines, these lines being connected by the same support structure, which acted as a thermal bridge. Ambiguities in the design documents allowed the installation of this type of thermal “bridge” between the two lines. In fact, such bridges have also been seen on other Fregat stages now under production at NPO Lavochkin. The design ambiguity is the result of not taking into account the relevant thermal transfers during the thermal analyses of the stage system design.

That the Russian investigation found that this arrangement of feed lines happened once in every four stages that were assembled still suggests sloppiness, if not in assembly then in design. The Arianespace investigation, though thorough, thus appears to me to be trying to provide cover for thier Russian partners here.

More quality control problems in Russia

The investigation into the failure of a Russian Soyuz rocket to place two European Galileo GPS satellites into the correct orbit has found that it was caused by the faulty installation of fuel lines on the Fregat upper stage.

The failure was as simple as clamping together a cold helium line with the hydrazine fuel line, causing the hydrazine to freeze long enough to upset the Fregat stage’s orientation and cause the two satellites’ release into an orbit that is both too low and in the wrong inclination, officials said. One official said the Euro-Russian board of inquiry into the failure discovered that one in four Fregat upper stages at prime contractor Moscow-based NPO Lavochkin had the same faulty installation. ,,,,

Government and officials said the commission is debating how to proceed now that it knows that, as expected, the Fregat failure was not one of design, but of assembly and quality control. [emphasis mine]

In other words, 1 in 4 Fregat upper stations were routinely assembled improperly and no one noticed. The investigation also found that this assembly problem had existed on several past launches but because of the orbital requirements it had fortunately not caused any problems.

I want to emphasize that these kind of sloppy assembly issues have been occurring at a number of different Russian factories and different Russian companies. It seems to be systemic to the entire Russian aerospace industry, and it also appears to be getting worse.

Soyuz puts two satellites in wrong orbit

A Russian-made Soyuz rocket launched from French Guiana for Arianespace has placed two European Galileo GPS satellites into the wrong orbit.

Russianspaceweb suggests that the problem was caused by the rocket’s Russian Fregat upper stage. (Scroll down about halfway to read their report on this launch.)

Multiple independent sources analyzing the situation suggested that the Fregat upper stage had fired its engine for the right duration, however the stage’s orientation in space during the second or both maneuvers had probably been wrong. According to Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics and a veteran space historian, the Fregat’s angular orientation error during engine firing could reach as much as 145 degrees.

This failure is a triple whammy. It hits both Arianespace and Russia since the Soyuz was part of a partnership between the two. It also hits Europe’s Galileo GPS satellite, which after many years of development was beginning to move towards full operation.