China anunció este domingo el «fracaso» de una misión espacial para poner en órbita un satélite de comunicación, poco después del despegue de su cohete Larga Marcha 5 Y2, un tropiezo en el ambicioso programa aeroespacial lanzado por Pekín.
El cohete, segundo lanzado pesado de China, había despegado a las 19H23 (11H23 GMT) desde el centro espacial de Wenchang en la isla meridional de Hainan, según imágenes de la televisión estatal.
Pero «varias anomalías se produjeron en el pilotaje del cohete y la misión de lanzamiento fracasó», indicó poco después de las 12H00 GMT la agencia de noticias estatal Xinhua.
Se llevará a cabo una «investigación (…) para analizar los motivos del fallo», añadió esa fuente.
El lanzador Larga Marcha 5 Y2, que puede transportar hasta 25 toneladas, trasportaba el satélite de comunicación experimental Shijian-18 (7,5 toneladas) para colocarlo en órbita.
El objetivo del satélite era mejorar el acceso a internet y la recepción de canales de televisión en el conjunto del territorio chino.
El país asiático lanzó en noviembre de 2016, desde la misma base espacial, su primer cohete Larga Marcha 5, presentado entonces como el lanzador más potente de la historia de China.
El fracaso del lanzamiento de este domingo supone un inusual contratiempo en el ambicioso programa aeroespacial chino, en el que el régimen comunista ha invertido miles de millones de dólares para intentar reducir su retraso respecto a Europa y Estados Unidos.
Pekín considera la conquista del espacio, coordinada por el ejército, como un símbolo de la nueva potencia del país dirigido por el Partido Comunista.
China launched its second new rocket in the year. The Long March 5 rocket, lifted off from the Wenchang launch center on Hainan Island, off China’s southern coast, at 8:43 a.m. EDT (1000 GMT; 8:43 p.m. Beijing time), carrying to orbit an experimental satellite called Shijian-17, which is designed to test electric-propulsion technology. Capable of a 25 metric ton payload to low-Earth orbit (LEO), Long March 5 is among the most powerful rockets in service. Besides the scheduled launch of China’s upcoming space station, the Long March 5 will also loft Chang’e-5, a robotic sample-return mission to the moon. Chang’e-5 is currently scheduled to lift off sometime next year, Chinese space officials have said.https://m.slashdot.org/story/318335
Long March 5 suffers failure with Shijian-18 launch
July 2, 2017 by Rui C. Barbosa
China launched its second Long March-5 (Chang Zhen-5) rocket on Sunday carrying a super-heavy experimental communications satellite. The launch took place at 11:23 UTC from the Wenchang Space Launch Centre’s LC101 dedicated Launch Complex. However, with the Long March-5, carrying the Shijian-18 satellite, suffered an unspecified failure during what was only its second flight.
The launch was part of a shakedown period for China’s new rocket, which is set to play a major role in Lunar and Mars missions.
Issues with the launch were not immediately known, with commentators claiming all was fine with the launch, including a message of mission success after spacecraft separation.
However, and as observed during the coverage, parameters were becoming off nominal early in the flight. Official media then called the mission a failure less than an hour after the launch was conducted.
This was a rare live broadcast of a Chinese launch and it will likely result in pressure to further remove the Chinese rockets from international attention.
Per the mission, this launch also had the primary goal of lofting a new satellite into orbit.
The new Shijian-18 experimental communications satellite is based on the new DFH-5 satellite platform, developed by CAST (China Academy of Space Technology) of China Aerospace Science and Technology Corporation (CASC).
The DFH-5 satellite platform is a large trussed satellite platform of new-generation with a launch mass of 8000 kg, payload of 1500 kg, providing 18 kilowatts payload power, high load, high power, high heat dissipation, long life, scalability, etc., using a truss structure, high power distribution systems, advanced electronics and integrated multi-mode high-thrust electric propulsion and other advanced technology to meet the needs of communications and other devices.
The development of the DFH-5 platform will lead the technical innovation of the design and manufacture of spacecrafts and other relevant areas, promoting the upgrading of large satellite platform, supporting the development of civil space infrastructure and aerospace equipment, and creating new advantages in international commercial satellite market competition.
The new satellite would have used ionic propulsion system to reach the geostationary orbit. The LIPS-300 ion thrusters will also be used for orbital maintenance operations.
However, this satellite’s only destination will now be a watery grave.
The Long March-5:
Aiming the capability to have a space launcher capable of orbiting heavy cargo to the Geostationary Transfer Orbit (GTO) or to Low Earth Orbit (LEO), China approved the development of the Long March-5 family of launch vehicles on June 2004.
The new launcher family would meet the needs in the future launch service market, would be used to launch the modules for a large-scale space station, would help to maintain the development trend of China’s launch vehicle technology, and drive the development of economy and related high-techs in China with the development of new rocket engines, new welding techniques, upgrade the fight control systems, etc.
The new development program would design a series of launch vehicles rather than one launcher made for a specific mission.
This is to enhance China’s capability of accessing space; would apply advanced technologies, such as the large diameter core and the powerful thrust engine to increase the launch capacity dramatically, with the goal of launching 25-ton payloads to LEO and 14-ton to GTO; design a series of launch vehicles based on the principle of generalization, serialization and modularization, with the purpose of meeting the needs of launching different payloads; to use non-toxic and non-polluting propellant; and to be low cost, high reliability, and convenient for test and operation.
The launcher system envisioned a modularized concept using two newly developed engines and three standard modules. Originally the plan included three primary classes: 5-meter diameter core variants, a 3.35-meter diameter core variants and a 2.25-meter diameter core configuration.
The three standard modules were the H5-1 module (5 meter diameter with a length of 31.0 meter and equipped with two 50t LH/LOX engines, having a mass of 175t), the K3-1 module (3.35 meter diameter with a length of 26.3 meter and equipped with two 120t KO/LOX engines, having a mass of 147t) and the K2-1 module (2.25 meter diameter with a length of 25.0 meter and equipped with one 120t KO/LOX engines, having a mass of 69t).
From these initial concepts, the Long March-6 and Long March-7 launch vehicles were developed. A series of variants were proposed for the heavy launcher. Using the 5 meter diameter core stage and different combinations of strap-on boosters and an upper stage, six variants were proposed to achieve different payload capacities.
Configuration A would be able to launch 18 t to LEO, while Configuration B and C would be capable of lofting 25 t and 10 t to LEO, respectively. For GTO the Configuration D would be capable of launching 10 t, while the Configuration E and F would be capable of lofting 14 t and 6 t to GTO, respectively.
Eventually, only two variants were developed: the basic variant two-stage Long March-5 designed for GTO missions, and the single-stage Long March-5B designed for LEO missions. Both variants are fitted with four strap-on boosters of 3.35 m diameter.
The basic variant of the new launcher is a two-stage core vehicle (5 meter diameter) with four strap-on boosters (3.35 meter diameter). The vehicle is capable of launching 14,000 kg to GTO. Total length is 56.97 meter, gross mass of 869 t and lift-off thrust of 10,573 kN.
Inaugural flight was schedule for 2013, but the China Academy of Launch Vehicle Technology (CALT) and the Shanghai Academy of Spaceflight Technology (SAST) would have to endure a hard road to the first flight. Facing enormous technical challenges, the development of the YF-100 and YF-77 engines would delay the development of the new launch vehicle family.
Total length is 56.97 meters and gross mass is 869,000 kg, developing a lift-off thrust of 10,572 kN.
First stage length is 31.02 meters, with a 5.00 meter diameter. The first stage is equipped with two YF-77 engines consuming LOX/LH. The first stage has a gross mass of 175,800 kg with an empty mass of 17,800 kg.
The strap-on boosters have a length of 26.28 meters and a 3.25 meter diameter. Each strap-on booster is equipped with two YF-100 engines. Gross mass is 147.000 kg with an empty mass of 12,000 kg. The YF-100 consumes LOX and kerosene.
The second stage is 12.00 meters long, with a 5.00 meter diameter. Is equipped with two YF-75D engines, consuming LOX/LH. The second stage has a gross mass of 26,000 kg with an empty mass of 3,100 kg.
The YF-77 engine, developed by the Academy of Aerospace Launch Propulsion Technology (AALPT) is a high performance and reliability booster designed for the Long March-5 family. This is the first high-thrust cryogenic engine developed in China, taking a big technological step with respect to previous Chinese cryogenic Oxygen/Hydrogen engine, such as YF-75 which powers the LM-3A/3B’s upper stage.
The engine utilizes gas generator cycle with cryogenic LOX/LH2 propellants. Two YF-77 engines fly on the first stage of the Long-March 5 and each engine provides 700-kN in vacuum at an oxidizer-to-fuel mixture ration (O/F) of 5.5. The YF-77 develops 700 kN at vacuum and 510 kN at sea-level with a Isp of 430 seconds (vacuum) and 310.2 seconds (sea-level). Burn time is 520 seconds.
The YF-100 development began in 2000 at the Academy of Aerospace Liquid Propulsion Technology. The engine was certified by the State Administration of Science, Technology and Industry for National Defence (SASTIND) in May 2012. It is a staged combustion cycle engine developing 1,199.19 kN at sea-level with a Isp of 300 seconds (vacuum values are: thrust 1,339.48 kN; Isp 335 seconds). Burn time is 155 seconds. The YF-100 is also on the CZ-6 launch vehicle.
The YF-75D engine is a LOX/LH2 closed expander cycle engine the is designed to meet the requirements of second stage propulsion of the new generation LM-5 launch vehicle for its performance, reliability, developing cost, schedule, etc. YF-75D engine is capable of throttling its mixture ratio and multi-start, so that it will be suited to various missions.
YF-75D engine has two turbopumps driven by gaseous hydrogen. They are designed in series and gimbaled with the whole engine. The YF-75D develops 88.26 kN at vacuum with a Isp of 442 seconds. Burn time is 780 seconds.
The cargoes orbited by the LM-5 are initially protected by a payload fairing with a 5.2 meter diameter and a 12.5 meter length.
Wenchang Space Launch Centre:
With the first orbital flight taking place on June 2016, Wenchang Space Launch Centre is located in the northeast corner of the Hainan Island on the southern coast of China.
The new launch complex brings a more large versatility that isn’t provided by the other three launch sites. Wenchang provides an increase in performance for the launch vehicles gained from the Earth’s rotational speed because is closer to the Earth equator. This reduces the amount of propellants required for the satellite’s maneuver from the transit orbit to GEO.
The launch vehicle can fly from the launch site to the southeast direction into the South Pacific, avoiding the possibility of rocket debris falling into any populated area.
The center is equipped with two launch complexes. Launch Complex LC101 is used for the Long March-5 launch vehicle family while Launch Complex LC201 is used for the Long March-7 launch vehicle.
Both pads are similar and are equipped with a fixed umbilical tower, underground flame deflector trenches and ducts. Similarly to what happens at the other Chinese launch centers, the umbilical towers have swing arms to allow technicians to access and inspect the launch vehicle and payload.
The launch pads at the new launch complex use a sound suppression system, spraying large volumes of water at the launcher platform and into the flame deflector trenches below to dampen sound waves generated by the rocket engines.
The launch pads are served by two vehicle assembly and integration buildings. Launch Complex LC101 is served by Building 501 while Launch Complex LC201 is served by Building 502.
Each building is 99.4 meters tall permitting the assembly and testing of the launch vehicle in a full, vertical stacked position. This is a new approach to the launch vehicle preparation for flight, because at the other Chinese launch centers the launchers are stacked and tested for flight at the launch platforms.
After being stacked at the vehicle assembly and integration building at the top of a mobile launch platform, this is the rolled to the launch pad. The journey takes several minutes to cover the 2,800 meters separating the vehicle assembly and integration buildings, and the launch pads. After arriving at the launch pads, the mobile structure is then placed above the flame trench and the necessary umbilical connections between the fixed structures and the mobile platform are established.
China’s most powerful rocket suffered a major setback on Sunday when it failed to send the Shijian-18 experimental communications satellite into orbit to test drive a new ultra-high-performance satellite platform.
China’s official Xinhua news agency confirmed the mission ended in failure and said an investigation was being convened, though details on the circumstances of the mishap are not yet clear.
Conducting its second launch, Long March 5 lifted off from a picturesque tropical launch site on Hainan Island at sunset on Sunday, rising into sunlight shortly after blastoff before disappearing in the night on its second orbital mission.
The 57-meter tall Long March 5 lifted off from Launch Complex 101 at the Wenchang Satellite Launch Center at 11:23 UTC, 7:23 p.m. local time – rising under the power of twin cryogenic engines and four Kerosene-fueled rocket boosters to begin a half-hour climb into a high-energy orbit.
All appeared to go by the book in the initial ascent phase until trouble struck some time after the rocket shed its four boosters. Separation of the core stage from the also-cryogenic second stage was around 100 seconds later than planned and the second stage’s burn did not match pre-flight prediction as the vehicle appeared to lose altitude.
It is not clear what lies at the root cause of the in-flight anomaly.
Sunday’s mission came after the debut launch of Long March 5 last November that saw the successful delivery of the Shijian-17 satellite directly to Geostationary Orbit in a mission surrounded by much more excitement than engineers had bargained for. Throughout the countdown and as late as T-2 minutes, engineers were scrambling to work around a string of problems from issues related to fueling to telemetry drop outs. The rocket’s inaugural mission was also not free from trouble as the second stage shut down around 11 seconds early, requiring the upper stage to make up for lost performance using generous margin built into the debut mission.
Engineers hoped they had ironed out all teething issues for Sunday’s mission that had the primary goal of validating Long March 5’s reliability to clear the heavy-lifter for high-profile missions starting with the launch of the Chang’e 5 lunar sample return mission in November. China will also rely on the Long March 5 for the launch of the Tianhe Core Module in 2019 as well as the two major science modules of the Chinese Space Station early in the next decade.
Long March 5 represents a cornerstone in China’s space ambitions and will be called upon for a variety of missions ranging from heavy hauls into Low Earth Orbit with Space Station components, launching the country’s heaviest geostationary satellites, to supporting solar system exploration by launching interplanetary probes such as China’s 2020 Mars rover.
Utilizing modern rocket technology like Kerolox and full cryogenic stages, Long March 5 closely matches or even surpasses the performance of current industry workhorses like the European Ariane 5, Russia’s Proton and the Delta IV Heavy, which still holds the rank as the most powerful launcher on the American market until SpaceX can introduce its Falcon Heavy which has about twice the performance of the CZ-5 (when flying expendable).
Long March 5 is the largest member in China’s new line of rockets that was introduced in the last two years to mark a major shift in rocket technology, stepping away from the hypergolic propellants used by the Chinese for more than four decades and introducing Kerolox and cryogenic propulsion systems that offer a much better performance at a fraction of the cost plus are more environmentally friendly.
Following its first flight in 2016, Long March 5 was expected to keep an initial pace of around two flights per year and preparations for the Y2 mission began back in late April when the Long March 5 was delivered via ship from its manufacturing plant in Tianjin. The fully assembled rocket with Shijian-18 under its payload fairing was moved to the LC-101 launch pad on June 26 for several days of checkouts prior to heading into countdown operations.
Long March 5 comprises two cryogenic rocket stages powered by Liquid Oxygen and Liquid Hydrogen, four Kerolox boosters for the initial kick toward orbit and an optional hypergolic-fueled YZ-2 upper stage that was not in use on Sunday and comes into play for Medium-Earth and direct-to-GEO missions. The vehicle weighs 867 metric tons at liftoff and spans 12 meters from side to side.
The Long March 5 rocket entered propellant loading at 8:30 UTC on Saturday, beginning with filling the four boosters with 150 metric tons of Kerosene stored at room temperature. Loading of cryogenic Liquid Oxygen into the boosters and the two stages as well as LH2 load on the core stages picked up on Sunday with no issues reported as the vehicle received some 580 metric tons of cryogenics. The protective Service Platforms opened up an retracted from the vehicle in the last four hours to launch and all tanks entered a stable replenish well ahead of liftoff.
Ignition sequence start was commanded at T-10 seconds and red flames erupted from the base of the rocket at T-6.8 seconds when the twin hydrogen-fueled YF-77 engines on the Core Stage were commanded to ignite followed at T-3 seconds by the eight YF-100 engines on the boosters – catapulting Long March 5 off the pad when clocks reached zero.
Long March 5 took flight at precisely 11:23:23.425 UTC, rising from its launch pad on Hainan Island in a vertical posture before pitching over onto a departure to the east-south-east to head towards the equator. Many spectators at China’s only publicly accessible spaceport watched in awe as Long March 5 thundered into twilit skies with a total thrust of 1,078 metric-ton-force, the boosters doing most of the work in the early flight phase, pushing the vehicle beyond the speed of sound just after hitting the T+1 minute mark.
The boosters fired until T+174 seconds, each generating 240 metric-ton-force of thrust to help accelerate the rocket to a speed of 2.8 Kilometers per second. Each used two YF-100s, an oxygen-rich staged combustion engine that builds the common element in China’s new line of rockets, also featured on the Long March 6 and 7, going back to Russia’s pioneering oxygen-rich closed cycle engine technology that China acquired in the 1990s.
Shutting down their engines after each consumed some 135 metric tons of Kerosene and Liquid Oxygen, the 27-meter long boosters separated from the still-firing core stage via pyrotechnics and separation rockets that propelled the boosters outward and away from the core which continued onward using its two YF-77 engines, generating a vacuum thrust of 143 metric ton force.
Where trouble emerged in Sunday’s flight is not entirely clear, however, a number of abnormalities became apparent from the live coverage provided of the mission.
Payload fairing separation occurred at the expected time, four minutes and 45 seconds into the flight and was met with applause by mission controllers – indicating there was no sign of any serious anomaly at that point in the launch.
Five minutes and 47 seconds into the flight, what until then was a well organized jet from the base of the rocket (likely the gas generator exhaust from the open cycle YF-77 engines) suddenly turned into a white cloud bursting away from the lower section of the core stage, indicating some type of breach in a pressurized system. The event appeared to be associated with a disturbance of the rocket’s attitude as evident by the sunlit horizon that moved rather rapidly. The venting cloud of gas was still present at T+440 seconds, per video from on board the rocket.
The two YF-77 engines of the core stage were expected to fire until 465 seconds into the flight (7 minutes and 45 seconds) to be followed within three seconds by the separation of the stages and the ignition of the two YF-75D expander cycle engines on the second stage. However, stage separation did not occur until 570 seconds into the mission, 105 seconds later than specified.
The second stage fired up at T+575.3 seconds according to telemetry displays at mission control, aiming to place the stack into a Low Earth Parking Orbit. However, as shown by the telemetry displays, the second stage was dropping in altitude – most likely due to insufficient velocity imparted by the first stage. The timing of when the decline in altitude started is a fairly good match with the emergence of the white gas cloud around the core stage.
Second stage shutdown was marked at T+770.3 seconds after a burn of only three minutes and 15 seconds, insufficient to place the stack into an orbit. Another observation at the start of the second stage burn was a large amount of gimbaling on the twin engines, likely to correct a rather significant deviation of the rocket’s orientation that built up toward the end of the first stage’s operation.
At this point, pacing got more nervous at Mission Control and fingers were pointing toward monitors as the realization sunk in that the CZ-5 Y2 mission would not be a successful one.
The original plan called for the second stage to fire for four minutes and 48 seconds to put the stack into a Parking Orbit around 170km in altitude followed by ten minutes of coasting and a 5-minute and 59 second burn to put Shijian-18 into a Supersynchronous Transfer Orbit of 200 x 46,000 Kilometers.
Why the second stage shut down prematurely when it clearly had not made orbit is not apparent – a typical scenario where the second stage starts out at a lower velocity than planned would see the stage extend its burn to reach orbit. One possibility could be that the second stage’s flight control system sensed there was no chance of reaching an orbit with the deficit on the first stage and thus shut down its engines. Another possibility is that the second stage was already in the process of re-entering when shutting down the engines.
Sunday’s mishap was China’s second unsuccessful orbital launch attempt in a row following the botched launch of the Zhongxing-9A communications satellitethat ended up in a lower-than-planned orbit when its Long March 3B upper stage encountered a serious issue. 2017 was expected to be a record-setting year for Chinese space flight with Chang’e 5 at the forefront, a launch that is now in doubt after two iffy missions for the Long March 5.
The Long March 5 Y2 mission carried the Shijian-18 experimental communications satellite – a milestone development for the Chinese, debuting a new ultra-high-performance satellite platform and featuring innovative systems like high-thrust ion propulsion, laser communications and ultra-secure quantum communications. Based on the DFH-5 satellite platform, Shijian-18 was the heaviest non-classified Geostationary Satellite ever launched, weighing in at just over seven metric tons according to press reports.
The DFH-5 platform builds on China’s current-generation DFH-4 but triples its payload capacity, hosting communications packages up to 2,200 Kilograms with a payload power up to a whopping 28 Kilowatts, surpassing the most powerful commercial platforms currently on the market.
DFH-5 inaugurates innovative systems like a truss acting as structural backbone, twice-deploying solar arrays, high-thrust ion engines for orbit control and a new type of self-controlling propellant system.
Shijian-18 hosted a powerful high-throughput communications payload operating in the Ka-Band frequency range and providing a total data throughput of 70 Gbps, eclipsing China’s first high-throughput satellite that launched earlier this year and has a capacity of 20Gbps.
State-run media also reported Shijian-18 was outfitted with an optical communications payload, taking advantage of the short wavelength of the infrared/visible spectrum to increase the bandwidth over radio communications ten- to one-hundred-fold. The laser terminal installed on Shijian-18 was to reach a downlink data rate of 4.8 Gbit/s, according to the satellite’s chief designer, paving the way for future high-data rate communications for application on Earth and over cosmic distances for solar system exploration.
Continuing China’s efforts in quantum communications and quantum computing, Shijian-18 was reportedly carrying a Quantum Communications Payload – the first to be tested from Geostationary Orbit over a distance of 36,000 Kilometers.
China has become a trailblazer in the field of quantum communications, launching the Mozi Quantum Science Satellite into orbit last year to demonstrate Quantum Key Distribution, the exchange of cryptographic keys between two parties, by means of correlated, or entangled photons – particles of light.
Quantum communications – governed by fascinating physics and offering many promising applications – are inherently secure, any attempt to eavesdrop on a quantum link is impossible. Prior to Mozi, quantum communications were only possible over a distance of a few hundred Kilometers; China planned to attempt to bring quantum communications to Geostationary Orbit with Shijian-18 which would enable a global quantum communications network to be established for full, hacking-proof communications.