China successfully conducted its fourth launch of 2017 with the successful deployment of the ChinaSat-16 (also known as Shijian-13) telecommunications satellite. Liftoff took place at 7:04 p.m. local time (11:04 GMT / 7:04 a.m. EDT) on April 12, 2017, from Launch Complex 2 at the Xichang Satellite Launch Center.
In a cloud of nitrogen tetroxide (N2O4) and unsymmetrical dimethylhydrazine (UDMH) byproducts, the 185-foot (56.3-meter) tall Long March 3B/E – also known as the Chang Zheng-3B/G2 – heavy-lift rocket roared off the pad in southern China.
The first stage’s YF-21C engine, along with a single YF-25 engine in each of the four boosters, produced a combined 1.3 million pounds (5,923.2 kilonewtons) of sea-level thrust to lift the 1.02-million-pound (458,970 kilograms) rocket and its 10,141-pound (4,600 kilograms) ChinaSat-16 payload off the pad.
The four strap-on boosters burned through their propellant in 2 minutes, 20 seconds before being jettisoned. The core stage exhausted its fuel nearly 20 seconds later.
With its job complete, the first stage separated as the second stage’s YF-24E propulsion cluster, consisting of a single YF-22E engine and four YF-23C vernier thrusters, continued the job of delivering the satellite to orbit.
Consuming the same N2O4 and UDMH hypergolic propellants as the first stage, the second stage burned through its 108,900 pounds (49,400 kilograms) of fuel in just over three minutes.
Now nearly six minutes into the flight, the third stage’s YF-75 engine ignited for the first time. The more efficient, liquid oxygen and liquid hydrogen-fueled power plant delivered the satellite to an initial low-Earth orbit, then was later re-ignited to deliver the satellite to geosynchronous transfer orbit.
Now detached from the third stage, the ChinaSat-16 satellite will use its onboard electric propulsion system to raise its orbit to settle in its slot 22,236 miles (35,786 kilometers) above the equator at 110.5 degrees East longitude. ChinaSat-16 represents the country’s first indigenous satellite to use electric propulsion.
Once in position, the satellite will provide high-bandwidth (20 gigabits per second) communications to China’s rail and air passengers, and it will be a platform to test an experimental space-to-ground laser communication system.
China’s next launch, tentatively scheduled for some time in April 2017, is the uncrewed Tianzhou 1 cargo spacecraft. Set to launch atop a Long March 7, Tianzhou 1 autonomously rendezvous and dock with the country’s Tiangong 2 orbiting space laboratory a few days later. Among the capabilities being tested during this mission, the spacecraft will demonstrate an ability to transfer propellant in space.
Written by: Curt Godwin
Original source: spaceflightinsider.com