China's Space Program News Thread

I was wondering why people are already talking about Chang'e 5 lunar mission when they mentioned nothing of Chang'e 4. Just like Chang'e 2 was really the backup if the first one failed, the same with 4 to 3. I guess they're just going to land 4 in a different exploratory region but maybe they should land it near the first Apollo landing site. That would peak a lot of people's interests.

maybe because CE 3 was already a huge success, CE 4 should at least add return rocket to earth so they can carry lunar sample back to earth this also test safety of their manned mission

AssassinsMace said:

I was wondering why people are already talking about Chang'e 5 lunar mission when they mentioned nothing of Chang'e 4. Just like Chang'e 2 was really the backup if the first one failed, the same with 4 to 3. I guess they're just going to land 4 in a different exploratory region but maybe they should land it near the first Apollo landing site. That would peak a lot of people's interests.

Click to expand...

a well deserve salute to the Chang'E lander and rover

....maybe they should land it near the first Apollo landing site. That would peak a lot of people's interests.

Click to expand...

Yeah...the conspiracy theorists are going to go wild on this!

AssassinsMace said:

I was wondering why people are already talking about Chang'e 5 lunar mission when they mentioned nothing of Chang'e 4. Just like Chang'e 2 was really the backup if the first one failed, the same with 4 to 3. I guess they're just going to land 4 in a different exploratory region but maybe they should land it near the first Apollo landing site. That would peak a lot of people's interests.

Click to expand...

The news was that they're going to change quite a bit on the mission plan for Chang'e 4. Originally it was a backup for Chang'e 3. If Chang'e 3 mission went as originally planned, there's no need to repeat the same mission plan with Chang'e 4. Wonder what interesting change of plan, they're going to come up with.

Engineer said:

The lander was not flying.


What Apollo landers did was not flying.


Yeah, but that's not flying.


You cannot fly in the moon as there is no air. You cannot hover indefinitely either, as that takes infinite amount of fuel.

Consider a simple thought experiment. You add more fuel to the Chinese lander so that it can hover longer. Now that you have added more fuel, the lander has more mass. More mass means the Moon can exert a more powerful pull on the lander through gravity, so the engine has to work harder to hover and burns more fuel. To compensate for that, you need to add even more fuel, which makes the lander even more heavier, leading to an even more powerful engine which burns even more fuel. It is a viscous cycle.

So, what you have suggested is simply not doable with current technologies. The closest you can do is send a probe to orbit the Moon at a very low altitude, such as what China did with Chang'e 2. However, that's not flying either.

Click to expand...

1. the lander hovered for a while before landing:

Was it doable? it did.

Was that called flying? i think it was flying - went horizontally in the air against moon gravity, albeit for a very short one.


2. Apollo came back, didn't it?

It means that even without air or with thin air, it somehow managed to overcome gravity from the moon surface upwards and went vertically at some stage, for some time.

Was that doable? of course, it did.

Was that called flying? i think of course it was flying - went vertically in the air against moon gravity, albeit using a lot of fuel.


So, from 1 and 2, they have managed to go both horizontally and vertically, against gravity - that's my definitonn of flying, and successful flying as well.

The difference however, from convetional flying, say, a F-16 jet fighter, is that the former required much more fuel, and lasted considerablely shorter time. Then still, they were flying.



The only fundamental questions here then become:

1. fuel economy (i.e. better and more efficient fuel types, to decide how far and for how long it flies)

2. a better weight-thrust optimisation (nonethelss, an optimation is already feasable as proven by above facts)

3. a combination of both verticle and horizonal moves ( to make a variety of different movements at that altitutue over time, to make it more like a drone on earth that we're familiar with)


All above 3 are questions of better tech and skills, but not about theoritical feasibility of flying itself, because they flied, after all.

Therefore, calling that one cannot fly a drone there simply because of thin air is a misnomer against the known facts.



Furthermore, think about long jump, can one jump on the moon surface?

Of course he can. And it's likely that he would break the world's long jump record as well.

When you jump before you land, you are effectively flying.

If you have some sustained fuel source, you fly longer before you're forced down by gravity.

If some push you a bit when you 're in the air, you then fly horizontally...

Therefore, even you yourself can fly at that altitute, the only question is for how long depending on external power plant.


A tiny drone the size of your keyboard , with a jet engine capable of directional thrusts and some high energy fuel, can be operated (pre-programmed? in the same manner as they did to the lander) both vertically and horizontally closely above the moon surface , say 30m or 100m, for some time like either 2 mins or 5 mins? or 10mins? even 20mins?... either way that's flying and that's enough in my book.

Though I doubt it would be pulled off, the success of CHang'e 3 opens the possibility of speeding up the manned program and a Chinese manned landing in 2019. That would be quite cool. Landing exactly fifty years after Apollo 11!
I think if they really wanted to do it, they could pull it off. All the necessary infrastructure and planning is probably already onggoing in various stages. All they need to do is some big push from Xi and some extra cash.

Maggern said:

Though I doubt it would be pulled off, the success of CHang'e 3 opens the possibility of speeding up the manned program and a Chinese manned landing in 2019. That would be quite cool. Landing exactly fifty years after Apollo 11!
I think if they really wanted to do it, they could pull it off. All the necessary infrastructure and planning is probably already onggoing in various stages. All they need to do is some big push from Xi and some extra cash.

Click to expand...

Why the big push? As much as I want to see my fellow countrymen land on the moon, I do feel that it's important we follow a well-planned, steady approach rather than just do it for the sake of doing it.

China has many ongoing projects now, and I think the space station project has a higher priority than landing a man on the moon. For one thing China has already detailed her plan and laid out very specific timeline as well as technical details of her future space station, while manned landing mission hasn't even been announced yet.

Also, I believe a Mars mission is also one of the higher priority projects. If not because of technical failure on the Russian side China's Yinghuo-1 would be orbiting the Red Planet by now. Since the window period for a Martian mission is very limited, I believe this will have a higher priority as well.

Not to mention the Long March 5/6/7 rockets as well as the Beidou (or Compass) positioning system, these are all more urgent than a manned Lunar landing.

After all my point is that we really don't need to rush it. Quite frankly, there's no way to rush it as well. What we need is well-planned, economical, purposeful as well as sustainable efforts in terms of space exploration. Slowly but steadily and surely, we will get there

Speeder said:

1. the lander hovered for a while before landing:

Was it doable? it did.

Was that called flying? i think it was flying - went horizontally in the air against moon gravity, albeit for a very short one.
.

Click to expand...

There was no air. The descent had enough thrust to completely arrest its downward fall under moon's gravity and hold the lunar lander stationary with respect to the moon's surface, and even move it around for about a minute or two using vernier thrusters. But the operative description is "for about a minute or two"

Speeder said:

2. Apollo came back, didn't it?

It means that even without air or with thin air, it somehow managed to overcome gravity from the moon surface upwards and went vertically at some stage, for some time.

Was that doable? of course, it did.

Was that called flying? i think of course it was flying - went vertically in the air against moon gravity, albeit using a lot of fuel.

.

Click to expand...

The ascent stage that lifted the manned portion of lunar module back off the surface of the moon also only had fuel for just a couple of minutes. A couple of minutes was all it took to reach the moon's orbital velocity from the lunar surface. So again, the key it could only be sustained for a very few minutes.

Speeder said:

So, from 1 and 2, they have managed to go both horizontally and vertically, against gravity - that's my definitonn of flying, and successful flying as well.

The difference however, from convetional flying, say, a F-16 jet fighter, is that the former required much more fuel, and lasted considerablely shorter time. Then still, they were flying.
.

Click to expand...

But conventional definition anything not physically supported from below and not in either free fall or falling at terminal velocity is flying. "Air" does not enter the description. So a space craft supporting itself on thrusters over lunar surface is certainly flying. You may argue something in free flight in space, or orbital flight around moons, planets and stars, are fact in total free fall, and therefore not flying. This is technically correct. But by custom we make this exception, and have come to call space travel "flying" as well.

Speeder said:

The only fundamental questions here then become:

1. fuel economy (i.e. better and more efficient fuel types, to decide how far and for how long it flies)

2. a better weight-thrust optimisation (nonethelss, an optimation is already feasable as proven by above facts)

3. a combination of both verticle and horizonal moves ( to make a variety of different movements at that altitutue over time, to make it more like a drone on earth that we're familiar with)


All above 3 are questions of better tech and skills, but not about theoritical feasibility of flying itself, because they flied, after all.

Therefore, calling that one cannot fly a drone there simply because of thin air is a misnomer against the known facts.



Furthermore, think about long jump, can one jump on the moon surface?

Of course he can. And it's likely that he would break the world's long jump record as well.

When you jump before you land, you are effectively flying.

If you have some sustained fuel source, you fly longer before you're forced down by gravity.

If some push you a bit when you 're in the air, you then fly horizontally...

Therefore, even you yourself can fly at that altitute, the only question is for how long depending on external power plant.


A tiny drone the size of your keyboard , with a jet engine capable of directional thrusts and some high energy fuel, can be operated (pre-programmed? in the same manner as they did to the lander) both vertically and horizontally closely above the moon surface , say 30m or 100m, for some time like either 2 mins or 5 mins? or 10mins? even 20mins?... either way that's flying and that's enough in my book.

Click to expand...

A jet engine by conventional definition is a thrust engine that draws oxidizer from ambient air. Therefore jet engine won't work where there is no air, or where air has insufficient oxygen to support the chemical reaction powering the engine. A thrust engine that is self-contained and not reliant on external oxidizer supply is usually called a rocket.

The reason why a jumper or a little hovering machine doesn't make top of anyone's list of equipment to bring to the moon is most important scientific discovery expected from lunar surface either requires instrument be precisely placed in direct contact or near direct contact with lunar surface; or can be adaquately done by remote observation from low lunar orbit. Therefore the premium on being able to look over an area from below orbital altitude after a lander has touched down is not high. Furthermore, most scientific observation needs validation by repetition. So an observation device with very low endurance of just a few minutes, and therefore would be mostly unable to repeat any observation, would be at a disadvantage.

The classic definition of "fly," and "flight," according to Websters, Meriram, Oxford, Cambridge, etc., is:

flight:
1. The action or instance of passing through the air, ie. by the use of wings.

Some others may define it as simply being able to move through open space, irrespective of a particular atmosphere. But that is not the classic difinition, the classic english language difinition is as I quoted above and what in the English language we understand when we say "flight," or "fly.".

However, that is irrelevent to this arguement. This current arguement has boilded down to a meaningless one. Both parties are correct in their assertions, but are now doing what we used to call, "straining at knats." That means in essence making a mountain out of a mole hill and doggedly sticking to text book definitions.

The Chinese orbiter used its rocket to slow its descent (and even hover) and land on the moon. Small UAVs would have to use rockets and attitude control to move through the space above the moon's surface. Call it flight, call it rocket powered movement, call it what you will.

Now, for the sake of the thread and keeping it on topic and avoding continued meaningless arguements:


Move on from the meaningless arguement about what we call the movement of an orbiter orother similar vessels. They do move, based on a power source, or some manipulation of elements and forces, through space, whether it has an atmosphere or not. The atmosphere just provides for different options in how they go about it...and when done therough "air," we classically call that "flight."