If we want to send a crew to mars we can do it now with current technology. If we send a rocket from erth directly to mars with a Departure velocity of 5.08 km/s we could get ther in only 180 days. A higher speed would make areo breaking dangerous, and a lower speed would extend the transit time.
A Hohmann transfer would take 258 days, and requer a departure velocity of 3.34 km/s. This would be the cheapest way of sending cargo to mars, but would be to slow for humans.
Both options are perfectly posible with a traditional chemical rocket burning hydrogen and oxygen.
For the return the roket could burn methane and oxygen. Methan and oxygen can be prodused from CO2 and hydrogen. There is plenty of CO2 in mars air, an and they would only need to bring about 6 ton of hydrogen to produse enough fuel for the return flight.
To reed more get the book "The case for MARS" written by Robert Zubrin
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If we want to send a crew to mars we can do it now with current technology. If we send a rocket from erth directly to mars with a Departure velocity of 5.08 km/s we could get ther in only 180 days. A higher speed would make areo breaking dangerous, and a lower speed would extend the transit time.
A Hohmann transfer would take 258 days, and requer a departure velocity of 3.34 km/s. This would be the cheapest way of sending cargo to mars, but would be to slow for humans.
Both options are perfectly posible with a traditional chemical rocket burning hydrogen and oxygen.
For the return the roket could burn methane and oxygen. Methan and oxygen can be prodused from CO2 and hydrogen. There is plenty of CO2 in mars air, an and they would only need to bring about 6 ton of hydrogen to produse enough fuel for the return flight.
To reed more get the book "The case for MARS" written by Robert Zubrin