68 votes
Accepted

Why don't we know exactly where the Chinese rocket will fall?

If the orbital period is about 90 minutes, that means ±45 minutes error at predicting the moment of landing means randomizing that point all around the globe. At the moment the prediction error is ± ...
SF.'s user avatar
  • 55k
43 votes
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Does the Long March-11 increase its thrust after clearing the launch tower?

Long March 11 is a cold-launched rocket, based on a concept popular with military rockets. A gas charge is generated by the launch platform (often using a chemical gas generator) to eject the rocket ...
Saiboogu's user avatar
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28 votes

Does the debris from the re-entry of Long March core stage ever reach the surface?

is it possible for the debris [of the Long March core stage] to hit earth's surface and possibly cause considerable damage to inhabited areas? Yes. Not only is it possible, but it has actually ...
Jörg W Mittag's user avatar
16 votes

Why don't we know exactly where the Chinese rocket will fall?

Why don't we know where this will fall? Because it went into orbit and it did not have any propellant remaining to perform a targeted reentry. The launch vehicle core stage has been in orbit for ...
David Hammen's user avatar
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14 votes
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What are these four "waffle-like" structures on top of the Long March 2F just launched?

From Spaceflight101: For Shenzhou Missions, a stretched version of the typical Long March fairing is used ... Four aerodynamic stabilizers are attached to the upper part of the fairing that is part ...
Russell Borogove's user avatar
13 votes
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CZ-4B Grid fins

TLDR the main purpose of the grid fins is to steer the spent 1st stage away from populated areas when it's falling to the grond. CZ-4B targets SSO and is mostly launched from T-SLC (Taiyuan Satellite ...
user3528438's user avatar
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10 votes
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Is it possible to know where the Long March 5B will be landed approximately?

Is it possible theoretically to know where and when the Long March 5B will be landed approximately? Yes! Take it from Jonathan McDowell @planet4589's tweet: The EU SST prediction is narrow enough ...
uhoh's user avatar
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8 votes
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Are these statements about "a first use of grid fins by China" simply wrong?

It's pretty rare to see popular news articles get technical details right, and this is no exception. The grid fins referred to in earlier QAs here are, as Polygnome notes, not maneuverable; they ...
Russell Borogove's user avatar
5 votes

Is it possible to know where the Long March 5B will be landed approximately?

You need to rephrase your question... Give a time frame? From right after launch, can we predict where it will re-enter? No. Too many variables. (Height and density of earth's atmosphere). Right the ...
geoffc's user avatar
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5 votes
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What's falling off the Shenzhou/Long March stack?

Those falling particles seem to be parts of a protective sheet that shields the opening around the interstage lattice between first and second stages. Only the Long Marches launched from Taiyuan and ...
Mys_721tx's user avatar
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5 votes
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First launch of Long March-5 using 4 RP-1/LOX boosters. First use of RP-1/LOX LRBs?

No. The 4 Soyuz boosters are RP1/LOX, this is a design that goes back to the R-7 that launched Sputnik 1. Thousands have been launched. Liquid boosters are a less common design than solids, but ...
Hobbes's user avatar
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5 votes
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Why does the YF-75D nozzle have such a strong spiral pattern?

According to the paper from the 64rd International Astronautical Congress, Beijing, China The Development of the LOX/LH2 Engine in China; IAC-13, C4.1, 1x18525, the nozzle was welded from spiral-...
Jan van Oort's user avatar
5 votes
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Are core stages going to start falling unpredictably from orbit somewhat regularly now?

Would this then be regarded as a single-stage-to-orbit, and a survivor of astronaut Don Petit's tyranny? No, Long March 5B uses strap-on boosters. From a certain level of abstraction, there's ...
Russell Borogove's user avatar
5 votes

Is it possible to know where the Long March 5B will be landed approximately?

Yes, it is now. The rocket has fallen down now and the approximate location where it fell is known. According to the China Manned Space Agency (as reported on their official website and quoted by ...
Ilmari Karonen's user avatar
4 votes
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Is it realistic to assume the Chinese Long March 5b "just missed New York"?

This comment is too long to fit as a comment, so I'll write it as a partial answer. Was this really as close as call as they make it out to be if it fell just off the west coast of Africa? ...
uhoh's user avatar
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4 votes
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How close to Guam did China's recent Long March 5's first stage fall?

@uhoh pointed to a tweet by LaunchStuff that shows images of what appear to be several Chinese notices to airmen (NOTAMs). (Weirdly, I can't find the originals of those; they don't seem to be in the ...
Bob Jacobsen's user avatar
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4 votes
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Comparing Long March 5's CZ-5-300 RP-1/LOX booster to Falcon 9 first stage; similar Isp's but very different relative volumes

Is there anything meaningful to this difference [?] It shows that it's a much smaller stage with a hat. The height of the Chinese booster includes its top cone. A quick measurement on the pictures ...
asdfex's user avatar
  • 15k
4 votes
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CZ-5 plus YZ-2 put SJ-17 in GEO - third stage or separate spacecraft?

A Honda Civic is a two axle vehicle. It can tow a trailer. When it's towing a trailer, Civic-plus-trailer is functionally a three axle vehicle. There's no essential difference between a spacecraft ...
Russell Borogove's user avatar
4 votes

Why couldn't China's space agency do a controlled deorbit burn for the Long March 5B?

A controlled reentry comes at a cost. China and SpaceX are apparently betting that the added cost of a controlled reentry vastly outweighs the cost of debris from an uncontrolled reentry resulting in ...
David Hammen's user avatar
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3 votes
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Why do the Long March 3B's strap-on boosters have fins? Is this common?

These are fixed fins, therefore they provide passive aerodynamic stabilization of the launcher at the cost of adding some drag and weight. The booster-less Long March 3A mounts four similar fins on ...
Russell Borogove's user avatar
2 votes

Why has China been slow in phasing out CZ-2,3,4?

Before we get into potential causes of the delay, I think it's important to say that the key focus of replacing CZ-2,3,4 wasn't to prevent booster on village syndrome it was to; To design a series of ...
Barry Jenakuns's user avatar
2 votes

What is this red gas at the exhaust of the Long March 3B rocket during liftoff?

From to @TildalWave's comment So the color at the exhaust actually shows how well it is mixed with hydrazine at fuel / oxidizer injectors and the efficiency of the engine? I don't mean these first ...
uhoh's user avatar
  • 149k
1 vote

First launch of Long March-5 using 4 RP-1/LOX boosters. First use of RP-1/LOX LRBs?

No. The Energia used kerolox strapons.
Organic Marble's user avatar

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