PARIS — Europe’s Arianespace launch consortium on Sept. 8 said it had booked four new commercial telecommunications satellite contracts, all for relatively lightweight satellites that this year have become the market’s favored satellite class.

At a press briefing here during the World Satellite Business Week conference, organized by Euroconsult, Arianespace said the contracts illustrate the company’s ability to win business in head-to-head competition with what has become its principal competitor, Space Exploration Technologies Corp. and the Falcon 9 rocket.

Individual satellite operators choose satellite and rocket suppliers using a range of criteria including schedule, price, recent launch record and export credit-agency financing.

It was not immediately clear how many of the latest satellite wins for Arianespace followed competitions in which SpaceX offered bids compatible with customer specifications and still lost.

Evry, France-based Arianespace lowered its prices for lighter satellites — those weighing up to 3,500 kilograms, which are placed in the lower berth of the Ariane 5 ECA heavy-lift rocket. It is this class of satellites, and some heavier ones as well, that Hawthorne, California-based SpaceX has made a specialty.

The satellites announced Sept. 8 are the JCSat-15 satellite for Sky Perfect JSat of Japan; the Intelsat 36 for Intelsat of Luxembourg and Washington; KT’s Koreasat-7; and London-based Avanti Communications’ Hylas-4.

The addition of these four brings to 11 the number of contracts signed this year by Arianespace. Company Chief Executive Stephane Israel said two others were about to be signed. The firm contracts, including new orders from European governments, have swelled the company’s order book to 4.6 billion euros ($6 billion). Two-thirds of the contract volume is commercial business; the rest is from government customers, mainly the 28-nation European Union.

The company has conducted seven launches so far this year, including the late-August failure of the Europeanized Russian Soyuz rocket to place two European navigation satellites into the correct orbit.

Israel said that assuming the Soyuz failure is identified and corrected in short order, the company plans one more Soyuz launch this year, one with the Vega small-satellite launcher and three with Ariane 5 rockets, each carrying two telecommunications customers.

In 2015, the company will face another crowded launch manifest and will attempt 12 campaigns of Soyuz, Vega and Ariane 5 rockets.

One focus for 2015 will be reducing the amount of time needed between two launches — seven weeks between two Soyuz campaigns and 14 days between an Ariane 5 and a Soyuz.

Arianespace’s two main competitors in the market for the launch of heavier satellites — Sea Launch AG of Switzerland, using a Russian-Ukrainian Zenit-3SL, and International Launch Services of Reston, Virginia, using Russia’s Proton — have both been crippled by recent failures and upheaval in their parent companies or supply chains.

That has focused Arianespace’s attention on SpaceX, which is developing a Falcon Heavy rocket designed to increase its payload-carrying power to compete for satellites that otherwise would sit in Arianespace’s upper berth as well as the lower position.