On Sunday, October 2, 2016 at 11:54:14 AM UTC+13, bob haller wrote:
at some point a nuke booster for travel from earth orbit to mars will be necessary..
to shorten travel time, and lessen supplies for the manned portion of flights.
a realtively small but very fast booster would be nice to have available for emergencies.
hey the water recycler is totally kaput, get earth to sen a replacement immediately!
of course sending one manned vehicle to mars with 2 backups flying close by will also help
Suspended animation, improved virtual reality, in combination with a long-duration second skin type spacesuit, can do much to achieve very efficient travel along hohman transfer orbits from Earth to Mars and back.
Nuclear pulse rockets of the 1950s can be improved dramatically with pyroelectric initiated micronukes using lithium-deuteride. These produce an exhaust in excess of 11,000 km/sec and can be built into a propulsive skin that efficiently controls the direction of beams collimated by plasmoids.
A ship boosting say 1 AU between Earth and Mars (the current distance for example) that's 150 million km approximately. 75 million km of boost, 75 million km to slow. That's 68.7 hours trip time at one gee. It achieves a top speed of 1212 km/sec A total delta vee of 2424. Add another 16 km/sec to escape Earth and land on Mars - this is 2440 km/sec each way. With an exhaust velocity of 11,000 km/sec this means 19.9% take off weight is Lithium-Hydride propellant!
The average cruise ship weighs from 20,000 to 60,000 tons, though cruise ship weights are usually calculated using gross registered tons. One GRT is equal to 100 cubic feet of enclosed revenue-earning space within the ship. Harmony of the Seas has 41.1 tons per passenger. This is 4110 cubic feet per person. So, 1,500 person ship would mass 60,000 tons - and consist of 12,000 tons of Lithium-6 Deuteride. This is 8 tons of propellant per passenger. Lithium hydrosxide costs about $6,000 per ton currently. So, using this as a measure, for Lithium-6 Deuteride, we have $48,000 per passenger for fuel cost. Again, $200,000 - is a reasonable figure - especially if you get a homestead in the bargain - and with 1,500 per trip - that's $300 million per trip. With an average of a one week turnaround - 50 flights per year - that's $15 billion per year per ship. At 600 per day (which was the flight rate considered before) you would need 4200 per week - or three ships in service - to match the fleet of 2300 chemically powered ships carrying folks in suspended animation described previously.
Mining Mars for Lithium-6 Deuteride and building LENR for consumption on Earth - this type of ship would be the poster child for clean fusion energy - made on Mars - used on Earth!
Each ship delivers 500 settlers, 500 returnees, and 500 visitors - this requires 9 ships to match the earlier chemical booster based settlers - departing in fleets of 2300 every 2.1 years. It would take 100 years to populate 1400 cities - at 14 per synodic period - but after 10 or 15 years - we can expect this sort of ship to replace the chemical booster based fleets - and with 90 such ships - all 1400 city states laid out during the first survey team - would be populated in 10 to 20 years thereafter.
Of course with this sort of propulsion and this type of ship - opens up the asteroids to development under similar terms and building large Bishop Ring style colonies among the asteroids.
YEAR POPULATION MINIMUM RATE -
2022 AD 8 billion 1159 ships 1.75 million/week
2033 AD 9 billion 1304 ships 1.96 million/week
2042 AD 10 billion 1449 ships 2.17 million/week
2051 AD 11 billion 1594 ships 2.39 million/week
2058 AD 12 billion 1739 ships 2.61 million/week
We can depopulate the Earth rather quickly, with 4,000 ships of the type just described, and build a very nice lifestyle among the asteroids for those who go there, and be ready to expand outward to the nearby stars - before the end of the 21st century!
http://www.iase.cc/openair.htm
https://www.youtube.com/watch?v=FZn5k8_my_o
https://www.youtube.com/watch?v=6xA2TmZxIK8