The Chinese have launched the third phase of its lunar exploration program on Thursday. Launch of the Chang’e-5-T1 mission took place at 1800UTC, utilizing a Long March-3C/G2 launch vehicle from the LC2 launch complex of the Xichang Satellite Launch Center, Sichuan Province. The mission is aimed at testing the technologies that are vital for the success of the future Chang’e-5 sample return probe.
In another flagship mission for the Chinese, the orbiter will head into Lunar Transfer Orbit (LTO), before performing a flyby around the Moon and re-enter the Earth’s atmosphere after a 9 day flight.
CLEP, the Chinese Lunar Exploration Program:
The CLEP was established in three different phases. The first phase aimed at orbiting the Moon, with the second phase having the objective of making a soft landing, while the third phase has the objective of return a sample of the lunar surface to Earth.
In 1991, Chinese space experts proposed a lunar exploration program and conducted a level of advanced research. China’s “Long March to the Moon” began in 1998 when the Commission for Science, Technology and Industry for National Defense (COSTIND) began planning the lunar mission, aimed at tackling major scientific and technological problems.
In November 2000, the State Council of China approved Phase I of the Lunar Exploration Program, i.e. Lunar Orbiting Exploration Project. The lunar orbiter project was formally established in January 2004, with the program named “Project Chang’e”, after a mythical Chinese goddess who flew to the moon.
In November of that same year, the Chang’e Program completed the design and development in concept phase and entered the prototype development phase. R&D and construction of a prototype probe were completed in December 2005.
A large number of key technological problems were solved through technical problem-tackling, system integration and relevant testing.
The first mission, Chang’e-1, was successfully launched on October 24, 2007, entering in lunar orbit on November 7.
Following the transmission of the Chinese song “Ode to the Motherland” and a number of images, the probe impacted the moon on March 1, 2009, after carrying out a comprehensive remote sensing survey of the lunar surface, obtaining a 120 meter resolution full moon image map, as well as an elevation map and element content distribution on the surface.
The probe operated for 494 days in lunar orbit.
Chang’e-2 was launched aboard a Long March 3C rocket on October 1, 2010, starting the second phase of the program. The objective of the mission was to validate some of the key technologies of landing as well as searching landing area for the Chang’e-3 mission.
Arriving October 9 in a circular orbit 100 km over the lunar surface after a 112 hour flight, six engineering objectives and four scientific missions were completed on April 1, 2011, including surveys of the south and north poles of the moon, taking high-resolution pictures of the chosen landing site for Chang’e-3.
The extended mission saw the probe depart towards a close encounter with the asteroid 4179 Toutatis, reaching to 3.2 km from its surface.
Chang’e-3, launched on December 1, 2013, conducting the first soft landing on the Moon on December 14 in the plains of Mare Imbrium. The main objectives of the mission were to conduct a survey of the Moon surface morphology and its geological structure, to analyse the components of the lunar surface and to implement optical astronomical observations.
With a launch mass of 3,780 kg, the lander came equipped with a radioisotope thermoelectric generator (RTG) to power the lunar operations during the three-month mission. The energy was used to power the scientific payload of seven instruments and cameras. The main instrument – the Lunar-based Ultraviolet Telescope – was designed to observe galaxies and other celestial objects.
The lunar rover, named Yutu, explored the lunar surface after departing from the lander. The small rover was equipped with a solar panel to power the vehicle during the lunar day on what was projected to be a three month mission. During this time, Yutu would explore a three square kilometer area, travelling a maximum distance of 10 km from the landing point.
Yutu carried a radar unit on its belly that allowed for the first direct measurement of the structure and depth of the lunar soil down to a depth of 30 meters. The unit was also able to investigate the lunar crust structure down to depth of several hundred meters. The rover was also equipped with an alpha particle X-ray spectrometer and an infrared spectrometer.
After successful departing Chang’e-3 on December 15, Yutu performed flawlessly. However, control problems emerged before the second lunar night fell on January 25, 2014. The lunar program specialists said the problem was probably caused by the complicated lunar surface, including stones and dust, but this has not been confirmed.
Chang’e-4 was built as a back-up for Chang’e-3, with the mission also incorporating a lander and a rover. Scheduled for launch in 2015, the mission is now is under further analysis by the Chinese specialists.
The third phase of the lunar program aims to return two kilograms of lunar soil and rock samples back to Earth.
The more sophisticated Chang’e-5 mission, planned for 2017, includes unmanned sampling and returning, requiring technology breakthroughs in Moon surface takeoff, sampling encapsulation, rendezvous and docking in lunar orbit, as well as high-speed Earth reentry.
Chang’e-5 will carry landing and optical cameras, as well as a lunar mineral spectrometer, an instrument for lunar soil gas analysis and to analyse the lunar soil composition, a sampling sectional thermodetector, and a robotic drilling rig.
The Chang’e 5-T1 mission:
Chang’e 5-T1, one of the test models for Chang’e-5, was developed using a Chang’e 2 type spacecraft (acting like a service module) featuring the Chang’e-5 return capsule.
This return capsule is very similar to the Shenzhou manned return technology, so it is assumed that it was developed using the Shenzhou as a baseline model. The service module will be used for trajectory corrections, power supply using two solar panels and batteries, along with telemetry and commands transmission to and from the control center.
Following launch, Chang’e 5-T1 will be injected into a lunar free-return orbit, loop behind the Moon once and return to Earth to test the high speed atmospheric reentry of a capsule returning from the translunar voyage at 11.2 km/s.
On a circumlunar free-return trajectory around the Moon the perilune is behind the Moon and the spacecraft moves there in a direction opposite to that of the Moon in a 8-shaped trajectory.
The capsule carries a few experiments on board to expose bacteria and plants to the BLEO radiation environment.
After a nominal ascent the last stage will make a burn for a translunar orbit with injection occurring over the Pacific Ocean. There was no webcast for the launch.
After the nine day journey, the return module will separate from the service module.
The service module will be oriented by the service module before separation. The return module will make a skip re-entry prior to landing in central Inner Mongolia (Siziwang Banner).
Skipping the atmosphere at an altitude of around 60 km, the return module will be equipped with a precise guidance system, controlling the reentry angle. After returning momentarily to space, the capsule will then finally plunge on a fiery reentry before touching down with the help of parachutes.
The orbiter arrived in Xichang via air in southwest China’s Sichuan Province on August 10 and was then transported to the Xichang Satellite Launch Center.
The ‘4M’ mission:
The ‘4M’ mission will be launched along with the Chang’e-5-T1 mission. 4M is the Manfred Memorial Moon Mission, dedicated to LuxSpace founder, Prof. Manfred Fuchs, who died early this year.
The mission is a lunar flyby of a spacecraft that is attached to the last stage of the Long March 3C/G2 rocket on its Vehicle Equipment Bay. The project is conducted by LuxSpace, Grand Duchy of Luxembourg and is a quick, low cost mission aiming at global cooperation.
The payload of this mission is designated 4M-LXS, a 14 kg payload that was developed at LuxSpace.
The 4M-LXS amateur radio payload will transmit on 145.980 MHz ± 2.9kHz (-40°C to +125°C), Doppler max: -2200Hz, +1000Hz. The continuous transmissions will start 4670s (77.8 minutes) after launch (-0, +600s).
Five successive 1 minute sequences are sent during the 5 minutes cycle. The digital mode JT65B will be used, this can be decoded by radio amateurs using the free WJST software, there will also be ‘human readable’ tone transmissions.
The transmitter produces 1.5 watts to a simple Monopole antenna which should give a Signal to Noise ratio (S/N) comparable to amateur moon bounce (EME) signals at the Earth’s surface.
The payload is comprised by a primary power source – 28 high energy density, non rechargeable cells, guaranteeing the nominal mission whilst providing 6W to the payloads; a secondary power source (2 x 8 Triple layer solar cells and 4 x Li-Ion rechargeable cells); an onboard computer, FM430 and interface board; an I/Q modulator and a RF power amplifier, providing a nominal 1.5W into the antenna; an L/4 antenna and a RAD experiment from radiation dose determination on the trajectory.
The RAD experiment is a special chip from IC-Malagua (Spain), that is able to accurately measure the Radiation dose rate.
4M is a very simple mission that does nothing much more than transmit its callsign, a basic telemetry, the result of an experiment and some welcome messages. But the mission can bring back some very interesting results in the field of radiation and multilateration.
4M can help in the sizing of the appropriate radiation shielding for the next Moon mission as well as being the first basic trial for spacecraft navigation of the next Moon mission.
The integration of the LX0OHB-4M amateur radio payload was completed on October 12.
Launch vehicle and launch site:
This mission will also be the first flight of the Long March-3C/G2 (Chang Zheng-3C/G2) version of the Long March-3C launch vehicle that is primarily used for launching satellite to Geostationary Transfer Orbit (GTO). The new version features a stretched first stage and boosters.
The Long March-3C was developed to fill the gap between the Long March-3A and the Long March-3B, having a payload capacity of 3,800 kg for GTO or 9,100 kg for LEO. This is a three stage launch vehicle identical to the CZ-3B but only using two of the strap-on boosters on its first stage.
CZ-3C provides two types of fairing and two kinds of fairing encapsulating process and four different payload interfaces, which is the same as CZ-3B launch vehicle. The various fairing and interface adapter and the suitable launch capacity make CZ-3C a good choice for user to choose the launch service.
The development of the CZ-3C started in February 1999. The rocket has a liftoff mass of 345,000 kg, sporting structure functions to withstand the various internal and external loads on the launch vehicle during transportation, hoisting and flight.
The rocket structure also combines all sub-systems together and is composed of two strap on boosters, first stage, second stage, third stage and payload fairing.
The first two stages as well as the two strap on boosters use hypergolic (N2O4/UDMH) fuel while the third stage uses cryogenic (LOX/LH2) fuel. The total length of the CZ-3C is 54.838 meters, with a diameter of 3.35 meters on the core stage and 3.00 meters on the third stage.
On the first stage, the CZ-3C uses a DaFY6-2 engine with a 2961.6 kN thrust and a specific impulse of 2556.2 Ns/kg. The first stage diameter is 3.35 m and the stage length is 26.972 m.
Each strap on booster is equipped with a DaFY5-1 engine with a 704.4 kN thrust and a specific impulse of 2556.2 Ns/kg. The strap on booster diameter is 2.25 m and the strap on booster length is 15.326 m.
The second stage is equipped with a DaFY20-1 main engine (742 kN / 2922.57 Ns/kg) and four DaFY21-1 vernier engines (11.8 kN / 2910.5 Ns/kg each). The second stage diameter is 3.35 m and the stage length is 9.470 m.
The third stage is equipped with two YF-75 engines developing 78.5 kN each and with a specific impulse of 4312 Ns/kg. The fairing diameter of the CZ-3C is 4.00 meters and has a length of 9.56 meters.
The Xichang Satellite Launch Centre is situated in the Sichuan Province, south-western China and is the country’s launch site for geosynchronous orbital launches.
Equipped with two launch pads (LC2 and LC3), the centre has a dedicated railway and highway lead directly to the launch site. The Command and Control Centre is located seven kilometers south-west of the launch pad, providing flight and safety control during launch rehearsal and launch.
The CZ-3B launch pad is located at 28.25 deg. N – 102.02 deg. E and at an elevation of 1,825 meters.
Other facilities on the Xichang Satellite Launch Centre are the Launch Control Centre, propellant fuelling systems, communications systems for launch command, telephone and data communications for users, and support equipment for meteorological monitoring and forecasting.
The first launch from Xichang took place at 12:25UTC on January 29, 1984, when the Chang Zheng-3 (CZ3-1) was launched the Shiyan Weixing (14670 1984-008A) communications satellite into orbit.
(Images via Chinese Media and LuxSpace).