China's Space Program News Thread

[Temstar]

I'm all for giving the US a gram, hell let's do one better and give them two grams, one from the surface sample and one from the drill sample.

I'm just saying, give it to them after a few years when/if relationship improve, and after all the papers have been published.

 

[Temstar]

Which makes you wonder how the Apollo capsule survives the heat of reentry with just a single skip. Did the Apollo capsule have a better heat shield technology? If that's the case, why isn't the Orion capsule using it so that it can forgo the atmosphere skipping, or it can even have the capability to do both kinds of reentry?

The Apollo spacecraft still did employ lift in a similar way to spread out the heat flux, it just didn't do it to the same extent that Zond or Chang'e did.

Plus as always you can just brute force your way through such problems. Apollo might have had a slightly thicker heat shield relative to the capsule. Galileo Probe did a Jupiter atmosphere entry and half of the probe's mass had to be the heat shield for the other half to survive.

 

[silentlurker]

The Apollo spacecraft still did employ lift in a similar way to spread out the heat flux, it just didn't do it to the same extent that Zond or Chang'e did.

Plus as always you can just brute force your way through such problems. Apollo might have had a slightly thicker heat shield relative to the capsule. Galileo Probe did a Jupiter atmosphere entry and half of the probe's mass had to be the heat shield for the other half to survive.

Apollo total return mass was 5000kg, Chang'e is less than 400kg. Apollo absolutely had a thicker heat shield, but in a ratio to total mass I don't know.

 

[Quickie]

The Apollo spacecraft still did employ lift in a similar way to spread out the heat flux, it just didn't do it to the same extent that Zond or Chang'e did.

Plus as always you can just brute force your way through such problems. Apollo might have had a slightly thicker heat shield relative to the capsule. Galileo Probe did a Jupiter atmosphere entry and half of the probe's mass had to be the heat shield for the other half to survive.

I'm not so sure about the brute force idea. Once the temperature reaches the melting/disintegrating temperature of the material, the heatshield material will simply evaporate away no matter how thick the material is. Looking at the picture of the Apollo Capsule, the heat shield certainly doesn't look extraordinary thick (far from half the mass of the capsule) not to mention the thinner part of the heat shield on the side of the capsule.

 

[SciNews]

recap

 

[silentlurker]

I'm not so sure about the brute force idea. Once the temperature reaches the melting/disintegrating temperature of the material, the heatshield material will simply evaporate away no matter how thick the material is. Looking at the picture of the Apollo Capsule, the heat shield certainly doesn't look extraordinary thick (far from half the mass of the capsule) not to mention the thinner part of the heat shield on the side of the capsule.

I suggest you look up "Ablative heat shield"

 

[taxiya]

I have seen some posts comparing the reentry of Apollo and Chang'e 5 (possibly Orion). Here is some information that I have read to clarify.

1. Skip reentry is defined as the capsule enter the Entry Interface (EI), travel, then exit the EI, then enter again.
2. EI is defined by NASA as 400,000 feet (121.92km) from sea surface. EI is not precise definition because the atmosphere is becoming gradually thinner, not abruptly becomes vacuum. So a skip reentry can be defined as that the second peak altitude is around the same altitude of the EI regardless the definition of EI's altitude.
3. Apollo did NOT use skip. It's highest altitude after reentry was 260 000 feet. It never left the EI. It was called "double dip" because the altitude did raise during the course. See the diagram below
4. This "double dip" has nothing to do with "skip" because it's change of altitude does nothing to help the heat depicting nor the speed deceleration.
5. Skip reentry is NOT the only way to survive. But it is a better way and more elegant way. It saves structural mass by using thinner and lighter ablation shield. That is why Chang'e and Orion choose to do so.
6. As of how Apollo survive the reentry, it simply used a thicker and heavier shield. No secret.
7. Why did Apollo not use skip? It is the lack of high speed real time computing power for trajectory calculation onboard the capsule.
8. One may ask, but the Soviet did it. Remember the soviet skip also failed a lot, more than half, and they are all unmanned? NASA could not afford to have astronauts killed.

 

[by78]

CAS Space, also known as Zhongke Aerospace, is currently performing ground tests of its lineup of solid rocket engines (200-ton, 100-ton, 50-ton, and 10-ton). They aim to achieve commercial launch capability for its KZ-1 and KZ-2 series of 'modular' rockets by 2023.

 

[Tam]

Chang'e 5 orbiter still alive in space. It will be headed for a new extended mission towards a NEO.

https://twitter.com/i/web/status/1339490142206234624

We should look forward to the next mission now, headed for Mars in 2021.

 

[taxiya]

CAS Space, also known as Zhongke Aerospace, is currently performing ground tests of its lineup of solid rocket engines (200-ton, 100-ton, 50-ton, and 10-ton). They aim to achieve commercial launch capability for its KZ-1 and KZ-2 series of 'modular' rockets by 2023.

CAS seems to have taken over the works from CASIC. KZ series are CASIC's products up to this point.