a discussion about spaceflight

Post miles covered vs fatalities...

Space flight needs us to build bigger ships with rotational gravity. Grav plates don't exist.

500 metre diameter O'Neill cylinder with Inner torus rings. For a small ship like this. 2000 metres long will give a couple hundred people a ship. Outer most rings give Earth gravity, upper rings Mars gravity, Moon gravity. Central core will be for docking etc... Very little micro gravity.

An ion drive to provide very low acceleration. Constant but low. Rotation gives gravity. A ship like this lets 200 people go to Mars the Moon and Earth and back and forth.

You need rotation gravity to keep people alive on long trips. 200 people minimal lets you move enough people to make a difference. Eventually larger ships in the 10,000's of passengers to 100,000's will be needed. Assuming radical mass sterilizations are not employed. Earth can only support so many people and unless you have big ships people are going to run out of stuff on Earth.

We need big ships. 500x2000 metres to start. 7,000x14,000 metres is our current technology materials limit. Life support might be around 50,000 people. But you need somewhere to go. With cryo preserve you could carry millions. In 100 years you will need 1000, million people cryo preserved ships leaving Earth every year.

Earth population will be 50-100 billion and growing a billion every year.

We need big ships soon very big ships and after that Humongous ships.

Lord Skimper wrote:We need big ships. 500x2000 metres to start. 7,000x14,000 metres is our current technology materials limit. Life support might be around 50,000 people. But you need somewhere to go. With cryo preserve you could carry millions. In 100 years you will need 1000, million people cryo preserved ships leaving Earth every year.

Earth population will be 50-100 billion and growing a billion every year.

We need big ships soon very big ships and after that Humongous ships.

Skimper, where are you getting your numbers? Population growth, while rather explosive in the past 200 years, has started to slow; It peaked at 2.1% per year in 1962, and is currently at 1.2%. It is far more likely that Earth's population will peak at somewhere around 10 billion some time in the 22nd century.

Lord Skimper wrote:Post miles covered vs fatalities...

Now THAT is actually a relevant point.
Consider that in a common orbit, an orbiter will circle earth once every 90 minutes and you get some serious mileage to look at.

Grav plates don't exist.

Yet. We need to figure out how to play with gravity to get beyond the local area anyway, so there´s a BIG interest in it.

The E wrote:

Lord Skimper wrote:We need big ships. 500x2000 metres to start. 7,000x14,000 metres is our current technology materials limit. Life support might be around 50,000 people. But you need somewhere to go. With cryo preserve you could carry millions. In 100 years you will need 1000, million people cryo preserved ships leaving Earth every year.

Earth population will be 50-100 billion and growing a billion every year.

We need big ships soon very big ships and after that Humongous ships.

Skimper, where are you getting your numbers? Population growth, while rather explosive in the past 200 years, has started to slow; It peaked at 2.1% per year in 1962, and is currently at 1.2%. It is far more likely that Earth's population will peak at somewhere around 10 billion some time in the 22nd century.

Many have not noticed the decrease in population growth. Most of the developed nations now have negative rates, ex immigration. The US just joined that group.

Radiation may be the hardest problem to overcome for long trips outside Earth's magnetosphere. Heinlein's "Podkayne of Mars" covers most of this, as fiction. For centrifugal acceleration, balanced and tethered life support modules rotating around a center costs less at first. As passenger numbers increase, more modules are added until a full ring exists. Course change calculations would include gyroscopic effects. Is the solar magnetic field strong enough to allow a long conductive tether and proper design to allow pushing against it for reducing propellant mass