China's Space Program News Thread

[Richard Santos]

My main evidence for water on Phobos is the moon's low density: 1.8 g/m^3, while water is 1 g/m^3, rock is something like 3, and iron like 8. It is possible that Phobos is just a rubble pile: a lot of empty space inside the body could explain its low density as well.

As I have said, if Phobos has no water, we can substitute another body with abundant water, like the asteroid Ceres. Even at Ceres' distance the water would be almost free: we can use some of the mined water as propellant for moving the rest of the water. And the distance to the asteroid belt would hardly matter: once the first chunk of ice arrived from Ceres, more chunks of the stuff could be delivered at a steady pace, regardless of the distance.

With a steady supply of propellant for launching finished solar panels off the Moon, the SPS construction program would be quite efficient. We really could build enough of them to save the Earth from global warming.

the low density of Deimos and Phobos is now generally attributed to their being loose rubble piles accreted from debris blasted into orbit by large impacts on martian surface. their low gravity did not allow the accreting fragments to compact so they contain large internal voids.

The volatile you refers to in outer solar system bodies are not propellants. they are at most reaction mass. the difference between propellant and reaction mass is propellant supply their own energy. reaction mass needs to have energy added to them to propels an object. Just having reaction mass doesn’t get you anywhere. In inner solar system the energy could potentially come from solar panels supply electric power to vaporize or ionize the reaction mass. solar panels don’t work very well much part midway out the main asteroid belt due to reduced solar flux beyond about 3AU, where solar flux is about 1/10 what it is on earth.

Where will you get the energy to use all that reaction mass?

 

[Nutrient]

the low density of Deimos and Phobos is now generally attributed to their being loose rubble piles accreted from debris blasted into orbit by large impacts on martian surface. their low gravity did not allow the accreting fragments to compact so they contain large internal voids.

That is what I said.

The volatile you refers to in outer solar system bodies are not propellants. they are at most reaction mass. the difference between propellant and reaction mass is propellant supply their own energy. reaction mass needs to have energy added to them to propels an object. Just having reaction mass doesn’t get you anywhere.

Spare me your elementary chemistry. Most of the ice mined from Ceres can stay as ice until it reaches Luna. Only a small fraction needs to be converted to hydrogen and oxygen, and used to boost the rest of the ice towards the Moon. We can use solar power for the tiny fraction, even as diffuse as that power will be at the distance of the asteroid belt.

Of course, once the ice reaches the Moon, the abundant solar energy available there can turn the ice into hydrogen and oxygen. This implies a small solar farm on the lunar surface, in the megawatt range (as opposed to the terawatt range needed to feed the Earth in David Criswell's proposal).

Believe me, once the infrastructure is in place, the solar power satellites (SPSs) will be cheap -- especially if we use teleoperated robots to assemble them in GEO. The SPSs will be cheap enough to save the Earth from global warming. Cheap enough for many other things too.

 

[paleski]

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TAIYUAN, July 3 (Xinhua) -- China sent five satellites into planned orbits from the Taiyuan Satellite Launch Center in northern Shanxi Province on Saturday.

The satellite Jilin-1 01B, Xingshidai-10 and three Jilin-1 Gaofen 03D satellites were launched by a Long March-2D rocket at 10:51 a.m. (Beijing Time).

This was the 376th flight mission of the Long March rocket series, the launch center said.

 

[AndrewS]

That is what I said.



Spare me your elementary chemistry. Most of the ice mined from Ceres can stay as ice until it reaches Luna. Only a small fraction needs to be converted to hydrogen and oxygen, and used to boost the rest of the ice towards the Moon. We can use solar power for the tiny fraction, even as diffuse as that power will be at the distance of the asteroid belt.

Of course, once the ice reaches the Moon, the abundant solar energy available there can turn the ice into hydrogen and oxygen. This implies a small solar farm on the lunar surface, in the megawatt range (as opposed to the terawatt range needed to feed the Earth in David Criswell's proposal).

Believe me, once the infrastructure is in place, the solar power satellites (SPSs) will be cheap -- especially if we use teleoperated robots to assemble them in GEO. The SPSs will be cheap enough to save the Earth from global warming. Cheap enough for many other things too.

Why locate this on the Moon, which has the disadvantage of solar energy being blocked by the Moon and Earth. Plus you would have to lift the hydrogen and oxygen from the moon's gravity well?

The L4 and L5 Lagrange would be better for a solar farm and electrolysis plant.

 

[AF-1]

Exercise bicycle has been set-up. The station is now more cluttered than ever with the CPC and PRC flag removed for space. Also, there's going to be an EVA broadcasted tomorrow at 13:13 China time.

What happened with this spacewalk friends? It happened, delayed...?

 

[KampfAlwin]

What happened with this spacewalk friends? It happened, delayed...?

Apparently, no longer scheduled. Maybe later in a few days?

https://twitter.com/i/web/status/1411175752972787717

 

[Nutrient]

Why locate this on the Moon, which has the disadvantage of solar energy being blocked by the Moon and Earth. Plus you would have to lift the hydrogen and oxygen from the moon's gravity well?

The L4 and L5 Lagrange would be better for a solar farm and electrolysis plant.

The solar panels for the SPS will be made from lunar silicon dioxide. We'll need to launch the finished panels off the Moon, so we may as well do the electrolysis there. But perhaps it'll be easier to land the water from Ceres as tanks of LOX and LH2 (produced at L5) than as large icebergs; we'll have to weigh the tradeoffs.

 

[AndrewS]

The solar panels for the SPS will be made from lunar silicon dioxide. We'll need to launch the finished panels off the Moon, so we may as well do the electrolysis there. But perhaps it'll be easier to land the water from Ceres as tanks of LOX and LH2 (produced at L5) than as large icebergs; we'll have to weigh the tradeoffs.

And there's no point in bringing ice down into the Moon's gravity well, only to have to lift all of it back up again anyway.

I see the vast majority of LOX/LH2 use as being used in space - not for launches off the Moon.

So I see few drawbacks to locating the majority of solar panels and electrolysis capacity at the L5 lagrange points, which doesn't require that much fuel.

Because solar panels spend 24h in the sun, rather than 12h on the surface of the moon, you halve the number of solar panels required to produce LOX and LH2.

Of course, it all depends on what viable industries emerge in space.

 

[Nutrient]

And there's no point in bringing ice down into the Moon's gravity well, only to have to lift all of it back up again anyway.

I see the vast majority of LOX/LH2 use as being used in space - not for launches off the Moon.

I see what you mean. I'm focusing on the solar power satellites (SPSs); I'm leaving anything beyond that for another day.

So I see few drawbacks to locating the majority of solar panels and electrolysis capacity at the L5 lagrange points, which doesn't require that much fuel.

In your scenario, a lot of mass would have to appear by magic at L5, if you want to make the solar panels there. If you don't believe in magic, then the raw silicon dioxide would have to come from somewhere, like the lunar surface, asteroid surface, etc. The propellants to move that SiO2 would have to be there, somehow. Perhaps we could find an asteroid with a lot of water, a lot of rock, AND a large and nearby source of energy. Until then, we will probably have to land the water on Luna somehow.

 

[KampfAlwin]

Hopefully.

https://twitter.com/i/web/status/1411479882857517059