Media playback is unsupported on your device Media caption US Space Force launches first national security mission

The US military's newest branch has launched its first satellite, despite a short delay in the countdown.

A rocket carrying a US Space Force communications satellite lifted off from the Cape Canaveral Air Force Station on Thursday.

An inaccurate reading on hydraulic equipment stopped the clock for 80 minutes before the issue was resolved.

US President Donald Trump established the Space Force, which is focused on warfare in space, in December 2019.

Lieutenant General John F Thompson, Commander of the Space and Missiles Systems Centre in California, explained why the launch was proceeding despite the Covid-19 pandemic.

"It is a really, really important launch," he said. "It's the very first launch for the US Space Force.

"There are critical things, or mission essential things, that the US Department of Defence does every day. Even in the face of a global pandemic we must continue to perform mission essential tasks.

"[The satellite] supports the president and other world leaders with critical communications around the planet. This launch extends that communication into a timeframe beyond 2030."

Image copyright ULA Image caption The Advanced Extremely High Frequency (AEHF-6) communications satellite during launch preparations

The countdown was held at T-Minus 46 seconds after an issue was discovered with a hydraulic accumulator - a device which collects fluid and keeps it under pressure for energy storage.

United Launch Alliance which operated the Atlas 5 rocket was able to sort matters before the end of Thursday's launch window.

The payload, the $1.4bn Advanced Extremely High Frequency (AEHF-6) communications satellite, will provide secure voice and data connections for the US government and its international partners, including the UK.

This was the first mission under the US Space Force.

It was announced as a sixth and separate branch of the US armed forces in 2018, described Mr Trump as "separate but equal" to the Air Force. The other US military branches are the Army, Navy, Coast Guard and Marine Corps.

The Space Force was then officially confirmed in December 2019 when the president signed the $738bn (£567bn) annual US military budget, with an initial $40m for the Space Force's first year.