Latest on Chinese 'Long March 5' 25 tonne payload rocket

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gunsandrockets

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"The CZ-5 is supposed to deliver 14 tonnes to GTO."<br /><br />As already pointed out in this thread, available sources on CZ-5 performance say different things. Some sources say the CZ-5 can deliver 14 tonnes to a geostationary orbit, in which case the payload to the moon would be even greater than 14 tonnes.
 
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krrr

Guest
"Some sources say the CZ-5 can deliver 14 tonnes to a geostationary orbit, in which case the payload to the moon would be even greater than 14 tonnes."<br /><br />Well it must be GTO. Even a fully fueled CZ-5 upper stage (wet 26000 kg, dry 3100 kg, Isp 448) couldn't make the ~4000 m/s delta-v to GSO with a 14 tonne payload.<br /><br />In reality, the upper stage will have to burn a significant amount of its propellant (~10 tonnes) just to reach LEO velocity. The remaining ~13 tonnes are consistent with the additional 2450 m/s for GTO.<br /><br />
 
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astrowikizhang

Guest
"Some sources say the CZ-5 can deliver 14 tonnes to a geostationary orbit."<br /><br />As my knowledge, current Chinese launch vehicles, like CZ-3A, CZ-3B, finish their job after pushing payloads to GTO. The upper stage is then jettsoned on GTO, and burned out at perigee. GEO circularization is realized by firing the rocket engines on payload at apogee. Usually the payload will be manufactured by a foriegn company, so only GTO capability makes sense to those rockets.<br />
 
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mlorrey

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"To restate the obvious, why cut down the Shenzou for a flyby mision when the proposed launch vehicle, the CZ-5, already has gobs of excess capacity to do the job? That doesn't make any sense. "<br /><br />To prepare for a CZ-5 launched lunar landing mission, of course. Without the OM, you could pack a one man open layout "jumper" style lander in there for the same mass. They could launch a Shenzhou with the existing launcher and a large transtage and full size lander with the CZ-5, dock in LEO and do the mission. Given they are going to be assembling a mini-station from OM modules left in orbit, they are going to be building up the skillsets for in orbit rendezvous.<br />
 
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themanwithoutapast

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What I really would like to know is, what the minimum mass of a lunar lander is (a "rocket-chair" type of thing) that is able to carry the mass of one astronaut to lunar surface from a 100 mile circumlunar orbit.<br /><br />Such a design would solely contain:<br />(1) a chair including avionics, controls and communication (no pressurized module) 150kg<br />(2) the astronaut with portable life support systems 200kg+<br />(3) engine + propellant ? kg for lunar descent and ascent (no separate ascent stage)<br /><br />I would estimate that at the minimum 3-5tons would be necessary. And before anyone says that such a construction would not have any purpose at all, imagine a US moon base in 2020 and a Chinese 1-man rocket chair moon lander to visit the base for a couple of days...
 
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krrr

Guest
<font color="yellow">What I really would like to know is, what the minimum mass of a lunar lander is (a "rocket-chair" type of thing) that is able to carry the mass of one astronaut to lunar surface from a 100 mile circumlunar orbit.</font><br /><br />When using hypergolic propellants (Isp 311 sec), the dry-to-wet ratio would have to be:<br /><br />27% for 4000 m/s total delta-v<br />22.9% for 4500 m/s<br />21.4% for 4700 m/s<br /><br />In the case of cryogenic propellants (Lox/LH2, ISP 433 sec):<br /><br />39% for 4000 m/s<br />34.7% for 4500 m/s<br />33% for 4700 m/s<br /><br />It's not easy to estimate the required delta-v (gravity losses, hover time), but 4700 m/s should be more than enough. The lightest Langley design in the early 60s was 1460 kg using Lox/LH2.<br /><br /><font color="yellow">(3) engine + propellant ? kg for lunar descent and ascent (no separate ascent stage)</font><br /><br />It all depends on the the additional dry weight for engine, tanks etc.:<br /><br />200 kg: total mass 2570 kg (hypergolic, 4700 m/s), 1664 kg (cryo, 4700 m/s)<br /><br />500 kg: 3970 kg (hypergolic, 4700 m/s), 2570 kg (cryo, 4700 m/s) <br />
 
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mlorrey

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You also want to consider that landing struts can be left on the moon, used merely as a launch platform.<br /><br />With computer guided descent and landing, with GPS-style circumlunar navigation, there is no need for "hover time" if you are just going to visit a moon base. Required dv from LLO to lunar surface is 1600 m/s. Thus 3300 m/s should be all a body needs, which should come out to dry/wet ratios about 45% for 433 sec Isp, and 32.5% for 311 sec Isp.<br /><br />Lets say we want the lunar equivalent of MOOSE: a set of tanks, engine, and landing struts which, with the mass of the astronaut, totals about 200-250 kg dry. This means about 525-750 kg propellant mass, thus under 1000 kg.
 
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vulture2

Guest
However much the US would like a new space race, China does not currently have any plans for manned lunar missions and is not interested in a new space race. As a Chinese friend says, "That is a portrait you have painted, not us."<br /><br />The risk is high if performance is stretched to the limit, the upside is negligible since they would not be first and, like Apollo, the effort would not be sustainable with current technology. The downside in the event of failure or simply losing an overt "race" is huge. Unmanned lunar probes can accomplish the same science with less cost and risk.<br /><br />The objective of human spaceflight for China is to raise the profile of their commercial space activities and build national prestige. The program is long-term and not under time constraints. We might want to consider cooperation (gasp!), like inviting them to join the "International" space station program. But if we are pinning our hopes on a new moon race to boost funding by US taxpayers we will be sorely disappointed.
 
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gunsandrockets

Guest
Resurrection<br /><br />Hi. I thought I would resurrect this old thread because I came across some new information about the Long March 5.<br /><br />The information that I could find when this thread began contained sketchy and sometimes contradictory information about the possible performance of the Long March 5. The new information I found reconciles those old contradictions.<br /><br />The heavy version of the Long March will have four hydrocarbon boosters and a 5 meter diameter hydrogen sustainer stage. This version of the LM 5 is supposed to place 25 tonnes payload into LEO. But in addition to that China also plans a large 5 meter diameter hydrogen 3rd stage. With this extra stage the the LM 5 is supposed to have a payload of 14 tonnes to GEO.<br /><br />Now the old information makes sense. Before now I didn't know the old GEO payload figures were based upon a larger Long March 5 with a 3rd stage.<br /><br />If the LM 5 with and without it's 3rd stage are analagous to the Saturn V with and without it's 3rd stage, I can make some guesses about potential LM 5 TLI payload. The Saturn V could place a payload of 77 tonnes into LEO without it's 3rd stage, and with it's third stage the Saturn V could TLI 47 tonnes. Based upon that I come up with a TLI of 15 tonnes for the Long March 5!
 
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dreada5

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<blockquote><font class="small">In reply to:</font><hr /><p>That said, given that Roskosmos would pull off a lunar flyby within 3 years, if someone comes up with the cash, a lunar flyby of a manned Shenzhou, say by 2015, is entirely possible. It would also make for great propaganda,<p><hr /></p></p></blockquote><br /><br />Indeed! Imagine that... China gets back (ok it'd be there first time) to the moon, before the US! <img src="/images/icons/rolleyes.gif" />
 
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vulture2

Guest
>>Do the Chinese still launch over populated areas, like they did when the Intelsat 708 launch killed all those people?<br /><br />They do, but a new launch facility on Hainan island, off the southern coast, is under construction to allow overwater launching as is done by the US and ESA. Safety isn't the stated reason (it will allow seaborn transport of boosters to the launch site and permit higher payloads at low incliniations) but avoiding more bad publicity was probably a factor.
 
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publiusr

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I love modular LVs, and had the US went for Energiya/Buran rather than STS--we would have been better off...<br /><br />--but...<br /><br />Having a whole slew of new propellant rockets to replace existing hypergolic vehicles that seem to be working just fine is a bit much.<br /><br />I would encourage the Chinese to build something like the 40 ton-to LEO R-56 (MONOBLOCK) using four RD-270s.<br /><br />This could then have strap ons with similar cores...
 
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bobv

Guest
Do you know the length of the 5 meter diameter fairing on the Long March 5?
 
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tomnackid

Guest
"Shenzou is also only a bit over 7.8 tonnes, leaving plenty of mass for a lunar lander. I suspect that this is what they will attempt to do: Shenzou and a lander, launched from the CZ-5, with no Orbital Module and expanded fuel tanks on the SM. This will allow them to go for a lunar landing. If the CZ-5 becomes viable before 2010, I'll bet that they just go and do it, not give any indication to the outside world that they are going to do it, and kick NASA in the teeth. "<br />____________________________________________________________<br /><br />They'll "kick NASA in the teeth" be replicating something NASA did over 40 years ago???
 
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scottb50

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The Chinese have already shown they can do everything needed, it's simply a matter of doing it. Three or four launches to put the pieces and people in orbit would be needed but they have already demonstrated they can do that.<br /><br />That they haven't leads me to believe they aren't that interested in an Apollo 8 mission and want to put people on the moon. What does orbiting the moon prove? The U.S. and USSR did it in the 60's. <div class="Discussion_UserSignature"> </div>
 
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astrowikizhang

Guest
The Long March 5 launch vehicle will be 59.4 meters long, with a launch weight of 643 tons and a lift-off thrust of 825 tons<br /><br />====================<br /><br />CZ-5's lift-off mass is nearly 100 tons less than the all LOX/LH2 Delta IV Heavy, is that practical for a partial Lox/Kerosene booster to put the same mass (25 tons) to LEO?
 
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gunsandrockets

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<CZ-5's lift-off mass is nearly 100 tons less than the all LOX/LH2 Delta IV Heavy, is that practical for a partial Lox/Kerosene booster to put the same mass (25 tons) to LEO?><br /><br />The CZ-5 by using mostly hydrocarbon 1st stage propulsion should be a more efficient launch vehicle than the all hydrogen Delta IV heavy. I think 5% more performance using 88% of the mass is possible.
 
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astrowikizhang

Guest
CZ-5 is still a three-staged launch vehicle, why don't they remove the 2nd stage and let the first stage burn longer, using the upper stage to kick payload to GTO? Just like many modern launch vehicles do.
 
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publiusr

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><CZ-5's lift-off mass is nearly 100 tons less than the all LOX/LH2 Delta IV Heavy, is that practical for a partial Lox/Kerosene booster to put the same mass (25 tons) to LEO?> The CZ-5 by using mostly hydrocarbon 1st stage propulsion should be a more efficient launch vehicle than the all hydrogen Delta IV heavy. I think 5% more performance using 88% of the mass is possible. <br />Posted by gunsandrockets</DIV></p><p>&nbsp;</p><p>It will be an impressive LV. A recent blurb in AV week states that the new Launch facility will ba capable of supporting Saturn V class HLLVs</p>
 
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qso1

Guest
<p><font color="#800080">Very unlikely they will carry out a manned flyby mission like Zond. <br /> Posted by astrowikizhang</font></p><p>Even Zond never carried man past the moon or to lunar orbit.&nbsp;</p> <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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Kevin_J_waldroup

Guest
<p class="BasicContentText">ChangZheng 5 (CZ-5, or Long March 5 in its translation) is a heavy load space launch vehicle (SLV) currently being developed by the China Academy of Launch Vehicle Technology (CALT). An important part of the PRC&rsquo;s space programme in the 21st century, the CZ-5 will provide a world-class SLV comparable in performance to the European Ariane 5. The first launch of the SLV is expected to take place in 2014.</p> <table border="0" cellspacing="0" cellpadding="0" width="470" bgcolor="#666666"> <tbody><tr> <td bgcolor="#f0f0f0"><div align="center"> </div>
 
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Kevin_J_waldroup

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<br /> <table border="0" cellspacing="2" cellpadding="2" width="604" align="center"><tbody><tr class="WhiteText" bgcolor="#999999"> <td>&nbsp;
 
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wubblie

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I think it's interesting to see that the new launch facilities will support Saturn V class lifters. This makes me wonder if the Chinese have plans to construct an Energia-clone lifter-- certainly Russia would be willing to help out (for a fee, of course).&nbsp; This would be a great plan for China to achieve parity with the US in space in a short time. Start launching Long March V lifters that can carry large space station components in 2012. Small space station by 2015. Energia-clone lifter flying by 2019. Moon mission by 2020.
 
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keermalec

Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>...they aren't that interested in an Apollo 8 mission and want to put people on the moon. What does orbiting the moon prove? The U.S. and USSR did it in the 60's. <br />Posted by scottb50</DIV><br /><br />Agree. The chinese are interested in putting men on the Moon. However, I believe the lunar flyby will certainly take place but not for political reasons: clearly for testing out the technology that will later put men on the Moon. This was the same reasoning behind Apollo 8. The mediatic effect was just a by-product. Today also, the international prestige gained by landing men on the Moon would be only a colateral effect. The Chinese are going to the Moon for a reason.</p><p>As I see no-one has posted anything on the matter: probably THE main drive behind China's Moon program is cheap and clean energy. Helium-3 mining on the Moon was very much talked about in the 1990's but seems to have disappeared from the radar since. The Chinese, however, have not forgotten:</p><p>&nbsp;</p><p><u><font color="#800080">http://www.guardian.co.uk/commentisfree/2007/oct/27/comment.comment</font></u></p><p>http://www.bbc.co.uk/blogs/newsnight/2006/06/china_goes_to_the_moon_for_helium_3_by_2024.html</p><p>http://english.pravda.ru/science/19/94/379/16403_moon.html</p><p>&nbsp;</p><p>More on topic now: the CZ-5 has the capacity to send a manned&nbsp;module on a circumlunar mission. However, its payload capacity is clearly too low for sending a manned lander of the Apollo type to the surface of the Moon. CZ-5 has exactly the same capacity as the US EELV (Evolved Expendable Launch Vehicle) ie Atlas V and Delta IV Heavies and, clearly, these are not even being considered for the US lunar program. China will have to develop a larger launcher yet to send a manned lander to the Moon.</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>
 
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