Rocket Motor for Ariane 6 and Vega-C is Cast for Testing

The first full-scale model of the P120C rocket motor that will propel Ariane 6 and Vega-C into orbit was cast and filled with inert propellant for intensive testing in Europe’s Spaceport in French Guiana in September 2017. (Credit: ESA)

KOUROU, French Guiana (ESA PR) — The first full-scale model of the rocket motor that will propel Ariane 6 and Vega-C into orbit has been cast and filled with inert propellant for testing at Europe’s Spaceport in French Guiana.

The P120C is the largest solid-propellant rocket motor ever built in one segment.

Each P120C will hold over 140 tonnes of propellant in a carbon fibre casing almost 11.5 m long and about 3.4 m in diameter. It is derived from Vega’s current first stage motor, the P80, which holds 88 tonnes of propellant.

The design builds on existing expertise and lessons learned with Vega’s P80, and it increases Vega performance with Vega-C. Two or four P120Cs will be strapped onto Ariane 6 as boosters for liftoff.

The model casing, shipped this summer from Avio in Italy, took about 36 hours to fill with inert propellant blended at Europe’s launch base in Kourou.

Using non-ignitable fluid that has a similar density to the real propellant meant that engineers could safely test all the new equipment and procedures.

Filled and sealed, the fluid in the casing could stabilise, cool and harden – the curing process – which took 10 days.

Further tests on the motor, now horizontal, will confirm that it is ready to be integrated with other structures in January.

These tests are a step towards casting active propellant in November with a P120C development motor that will be static fired in April.

Vega-C is expected to debut in mid-2019, increasing performance from Vega’s current 1.5 t to about 2.2 t in a reference 700 km polar orbit.

Ariane 6’s maiden flight is planned for 2020. This new launch vehicle will be gradually phased in to succeed Ariane 5.

  • Mr Snarky Answer

    Solid propellant…how quaint. Like a wagon train.

  • James Robertson

    “The P120C is the largest solid-propellant rocket motor ever built in one segment.”

    This may be the largest being built today, but not of all time. They must have overlooked Aerojet’s monolithic 260-inch motors of the 1960’s:

  • What did they replace the AP with? That teal color is kinda funky.

  • Aegis Maelstrom

    Solid is solid 🙂 and considering the manufacturing process these wagons are made of carbon fiber and whatnot. 🙂

    If only it’s not overengineered like ATVs it will be a pretty elegant and effective train – just what some people enjoy in Europe 😀 and more people in U.S. could too.

    And don’t worry, U.S. will eventually run its solids upgrade programme as well.

  • Aegis Maelstrom

    Interesting! It does look like a built in one segment, real monster – could’ve been forgotten as it was never flown, only ground tested.

    Must have been pretty expensive – I wonder if it was a key reason of shelving it back then.

  • Mr Snarky Answer

    Nope, solids are fundamentally incompatible with rapid and complete reusability. Therefore their share of the launch market (flights using solid boosters) will in all reality decrease precipitously over the next 10 years.

    And just to tweak Doug, the iron horse is coming and the wagon train will be relegated to the dust bin.

  • Aegis Maelstrom

    Yes, I know they are non-reusable (unless someone impresses us, who knows) but it is a dual-use technology and ballistic missiles are not really reusable because of their nature. 🙂

    Countries tend to prefer to keep this tech at least strategicwise.

  • Mr Snarky Answer

    That gig is up. The launch industry is no longer a Christmas tree to festoon with strategic technologies vacuous to the mission at hand. You are thinking 1990s…it’s almost 2018…game on for highly efficient launch services.

  • Aegis Maelstrom

    I hear you but this is a strategic decision they made some time ago – they bet that probably SpaceX would not be as successful as it is now and that they would not compete directly, at least this round.

    Not knowing their all resources but knowing they have a few countries to please and a number of gains to provide + that there is a limited market for launches (they still are not free and the spacecraft has costs) + US govt will buy SpaceX or other US craft and it will buy more than ESA/EU I understand why they could come up with this decision. I wrote some lengthy comments on SpaceNews why this choice was not crazy so I won’t repeat myself.

    Admittedly, they have a long story of overly conservative choices: they harmed Ariane 5 ECA with it and killed ECB in effect :(, they postponed a lifting body ad nauseum and they resigned from recoverability of Ariane 4!

    So yes, blame them. OTOH, high ISP, low dry mass and volume solid launcher is nice for industry and supergreat for nuclear subs. Just saying.