WASHINGTON — A last-second abort halted an Ariane 5 launch of two telecommunications satellites Tuesday evening.

The abort occurred at 5:51 p.m. Eastern just after the Ariane 5’s cryogenic main engine ignited but before the rocket’s two solid-fueled strap-on boosters were to ignite about 7 seconds later. Had the side boosters fired, the rocket would have been propelled upwards since solid fuel keeps burning once ignited.

Arianespace said the rocket and its two-satellite payload, Intelsat-37e and Bsat-4a, were safe following the aborted launch. The rocket will be transferred back to its assembly building at the French Guiana spaceport to undergo preparations for a second launch attempt while Arianespace analyzes what caused Tuesday’s abort.

In a brief webcast following the launch scrub, Arianespace said the mission would be rescheduled “very soon,” but did not give a timeframe.

Intelsat-37e is the third and final satellite launch this year for Luxembourg- and Washington-based fleet operator Intelsat. The Boeing-built satellite is part of the company’s high-throughput “EpicNG” series, and carries 45 Gbps of capacity across C-, Ku- and Ka-band payloads.

Bsat-4a is a broadcast satellite for Japanese satellite operator Broadcasting Satellite System Corporation (B-SAT). Space Systems Loral built the satellite with 24 Ku-band transponders meant to support increasingly higher quality video broadcasts in Japan including 4K ultra-HD and, notably, 8K — a bandwidth intensive broadcast that offers 16 times the resolution of high definition.