[ti:SpaceX to Build Missile-Tracking Satellites] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:01.04]SpaceX has been chosen by the U.S. Defense Department [00:06.24]to build missile-tracking satellites. [00:09.56]The $149 million contract, or legal agreement, [00:16.20]was announced by the U.S. Space Development Agency (SDA) this week. [00:24.32]The SDA is an agency under the Department of Defense. [00:30.64]It is the first time SpaceX has won a government contract to build satellites. [00:38.20]The American aerospace company is best known for its rockets. [00:43.96]In May, SpaceX made history by launching two astronauts into space [00:50.56]aboard a rocket and spacecraft the company built and operated for NASA. [00:57.32]SpaceX has increased its satellite production in recent years for its Starlink network. [01:06.04]Starlink is a group of satellites - deployed to low-Earth orbit [01:11.72]- designed to send internet signals across the world. [01:16.60]SpaceX chief Elon Musk has said he hopes Starlink will make enough money [01:23.72]to help pay for the company's space travel goals. [01:28.52]Under the contract, SpaceX will use its Starlink plant [01:33.88]in Redmond, Washington, to build four satellites. [01:38.60]The satellites will have a special missile-tracking sensor [01:43.28]supplied by another company, an SDA official said. [01:48.36]The SDA also awarded a $193 million contract to technology company [01:56.80]L3 Harris Technologies Inc. to build four additional satellites. [02:03.92]Both companies are expected to have the satellites ready for launch by fall 2022. [02:12.84]The awards represent the start of SDA's plan [02:17.32]to develop a system of satellites in low-Earth orbit [02:22.00]to detect and follow missiles, such as intercontinental ballistic missiles (ICBMs). [02:31.84]ICBMs can travel long distances and are difficult to follow and intercept, or stop. [02:40.76]In 2019, SpaceX won a $28 million contract from the U.S. Air Force. [02:49.40]The contract permits the Air Force to use the Starlink satellite network [02:55.28]to test encrypted internet services on military planes. [03:00.92]The Air Force has not ordered any Starlink satellites of its own. [03:06.44]I'm John Russell. 更多听力请访问51VOA.COM