{"id":2918,"date":"2020-04-01T11:42:00","date_gmt":"2020-04-01T10:42:00","guid":{"rendered":"https:\/\/orientspace.pl\/?p=2918"},"modified":"2020-06-23T12:31:26","modified_gmt":"2020-06-23T11:31:26","slug":"failed-launch-of-a-chinese-cz-7a-rocket","status":"publish","type":"post","link":"https:\/\/orientspace.pl\/?p=2918&lang=en","title":{"rendered":"Failed launch of a Chinese CZ-7A rocket"},"content":{"rendered":"\n

The first attempt to launch the Chinese CZ-7A rocket failed during flight with an experimental telecommunications XJY-6 satellite onboard. The ill-fated flight took place on the 16th of March. It was already the third launch by a rocket from the CZ-7 family.<\/p>\n\n\n\n

To give you a broader context I would like to write a few words about the naming convention of Chinese rockets. CZ is an abbreviation from Chang Zheng (\u957f\u5f81) and refers to the Long March war campaign, a historical event from the beginnings of communist China. English sources name this launcher family as Long March or abbreviate it as LM. Under this name there are several rocket variants intended for placing different payloads into a range of orbits. The exact rocket configuration can be identified by the number and letter following the CZ abbreviation.<\/p>\n\n\n\n

Does it sound complicated? Yes. But if you like to look into such details, then I recommend a very good comparison on the English Wikipedia page<\/a>. With this reference list it is easier to check  and compare all technical issues.<\/p>\n\n\n\n

Coming back to the main story. The rocket took off from the Wenchang Spacecraft Launch Site (\u6587\u660c), the latest Chinese spaceport, built on the Hainan island on the most southern part of continental China. Due to this localization, the launching rockets can carry a heavier payload. Simply spoken, the closer a spaceport is located to the equator, the more support from the Earth\u2019s spin can be transferred into the launcher capability, and by this increase the rocket\u2019s capabilities. Thus, the Wenchang launch site will be soon used to launch heavy modules of the new space station, and in the longer perspective, to conduct future lunar missions.<\/p>\n\n\n\n

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CZ-7 in the basic configuration \/ CASC<\/figcaption><\/figure><\/center>\n\n\n\n

The Chang Zheng 7 launch vehicle<\/h4>\n\n\n\n

In the basic configuration the CZ-7 is intended to meet the demands of the Chinese human spaceflight programme. In its inaugural launch in June 2016, also from Wenchang, the rocket carried a resized dummy capsule of the new Chinese crewed spacecraft.<\/p>\n\n\n\n

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A image snap of the new chinese capsule from CCTV footage<\/figcaption><\/figure><\/div><\/center>\n\n\n\n

During its second flight in April 2017, it launched the first mission of the uncrewed Tianzhou (\u5929\u821f) logistic spacecraft. The Tianzhou-1 mission performed the first on-orbit fuel transfer to Tiangong 2, a small experimental space station module. It was a critical experiment, which will allow the planned future space station to keep a stable low Earth orbit. This is required as trace particles from the Earth\u2019s atmosphere can still slow, and in effect deorbit any spacecraft at low altitudes.
In the future, Tianzhou vehicles will provide not only fuel, but also hardware and supplies for the new space station, similar as the Russians did it with their Progress spacecraft from the end of the seventies.

The maiden launch of the rocket in the CZ-7A configuration was to carry a payload called Xin Jishu Yanzheng 6 (XJY-6), meaning\u2026 \u201cnew technologies verification satellite\u201d in English. Do not ask for more details, as they are not present in the open access section of the web. Or at least they should not be there. (I still looked for it!)<\/p>\n\n\n\n

Geostationary Transfer and Geostationary Earth Orbits<\/h4>\n\n\n\n

More hints of the payload can be determined by looking more closely at the used rocket variant. The letter A in CZ-7A means, that a configuration of CZ-7 with an additional third liquid fuel stage was used in this flight. This stage is nominally used in CZ-3B rockets to launch payloads into Geostationary Transfer Orbits (GTO), elliptical orbits reaching as far as 35 786 km above the Earth\u2019s surface.<\/p>\n\n\n\n

Satellites launched into such orbit use their own engines, to enter a circular Geostationary Earth Orbit (GEO). From such orbit the satellite is always facing one point of the surface. Usually transmissions from such satellite we receive through a firmly installed satellite dish. The GEO orbit is mostly utilized by telecommunication and meteorological satellites. How the transfer from GTO to GEO happens can be seen on the animation below.<\/p>\n\n\n\n

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Example of a transfer from GTO orbit to GEO (EchoStar XVII satellite). Source: HORIZONS System<\/a>, JPL, NASA, CC BY-SA 4.0<\/figcaption><\/figure><\/div>\n\n\n\n

Failure causes and consequences<\/h4>\n\n\n\n

Well, but what was really the cause of the failure? In this case there is a number of hypotheses. At first notice of a failed launch, users from 9ifly, the main Chinese language forum on aerospace issues, suggested problems with the third stage. On the other hand social media users showed an amateur recording of the launch, which might suggest the failure\u2019s issue in the second stage.<\/p>\n\n\n\n

As Chinese rockets are having modular components with a high level of exchangeability, so this failure could lead to the grounding of other launch vehicles. A thorough investigation process will now check, whether a production error could have led to the launch failure, and if such error could be found in other components.<\/p>\n\n\n\n

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So, no new info on the failure of the Long March 7A today & could be some time before anything official. What we have is amateur footage. This apparently shows MECO & 2nd stage ignition. But seconds later: BOOM. pic.twitter.com\/ahTd0f0Lrf<\/a><\/p>— Andrew Jones (@AJ_FI) March 17, 2020<\/a><\/blockquote>