China plans the second launch of its new heavy-lift Long March 5 rocket tomorrow, July 2. It will place the Shijian-18 (SJ-18) communications satellite into geostationary orbit, China’s heaviest satellite to date. China describes the launch as a final test before the rocket is used to send a robotic sample return mission to the Moon in November.

Long March 5 is one of a new fleet of launch vehicles developed by China that use environmentally friendly propellants — liquid oxygen (LOX)/kerosene instead of hydrazine. China’s largest rocket, it can place 25 metric tons (MT) into low Earth orbit (LEO) or 14 MT into geostationary orbit (GEO). Launches take place from the new Wenchang Satellite Launch Center on Hainan Island.

The first launch in November 2016 placed SJ-17, also an experimental communications satellite, into GEO.

SJ-18 is a 7 MT satellite that will test a new satellite platform, Dongfanghong-5 (DFH-5), developed by the China Academy of Space Technology (CAST) according to Andrew Jones at gbtimes.com. He adds that the throughput for SJ-18 is 70 Gbps, overshadowing the 20 Gpbs of the SJ-13 experimental high throughout satellite launched earlier this year. SJ-13 and SJ-18 both are testing space-based laser communications as well, he reports.

Jones tweeted that tomorrow’s launch is expected at approximately 11:20 GMT (7:20 am ET).

Just over a day til launch of Long March 5 (Y2). Liftoff expected ~11:20 UTC (07:20 ET) Sunday, carrying one of heaviest GEO-bound sats ever pic.twitter.com/nF8aXYpiGX — Andrew Jones (@AJ_FI) July 1, 2017

China has expansive plans for Long March 5 that include launching robotic missions to the Moon and Mars as well as three 20 MT modules that will be joined together in LEO to form a larger space station than the 8.6 MT space stations (Tiangong-1 and Tiangong-2) China has launched so far.

The November lunar mission is Chang’e-5, the long awaited Chinese mission to robotically return samples of the Moon to Earth. China hopes to return 2 kilograms of samples.

The Soviet Union conducted three successful robotic lunar sample return missions (Luna 16, Luna 20 and Luna 24) from 1970-1976, returning a total of 326 grams of lunar material. Six U.S. Apollo crews brought back 382 kilograms of lunar samples between 1969 and 1972.

China conducted a successful test flight in 2014 in preparation for Chang’e-5 to demonstrate reentry and landing from lunar distance. China already has launched two lunar orbiters (Chang’e-1 and -2) and a lander/rover (Chang’e-3/Yutu). Chang’e is China’s mythical goddess of the Moon. Yutu is her companion Jade Rabbit.