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The Saturn series might have been enlarged to a level (Nova) that would have been able to push a few hundred tons to Mars in a single launch. But it would have

The Saturn series might have been enlarged to a level (Nova) that would have been able to push a few hundred tons to Mars in a single launch. But it would have been a slow and super expensive (probably over $10B in today’s dollars for launch alone) trip, and it’s not clear if that’s enough mass to include a return vessel with enough fuel for any size crew. Given the limitations of nuclear engines, in orbit refueling is the key to making deep space travel possible and affordable. Starship is going to weigh around 100 tons empty, carry around 100 tons of passengers and cargo, but will be over 1,000 tons fully fueled in low earth orbit. That’s roughly four times the ship & payload that a Saturn V single launch could put into Mars intercept orbit, and Starship can reach Mars in half the time. And it’s cost could be as low as a few hundred million per Mars trip if performance goals are met, making it affordable to launch a fleet of dozens of Starships with hundreds of crews and thousands of tons of supplies and equipment every Synod. To do this Starship has to show that 1) It can launch and relaunch quickly without a lot of expensive maintenance. Not necessary for Mars versions, but critical for tanker versions needed to fuel them. 2) That its thermal protection system can handle dozens of reentries at very high velocities, such as Mars Intercept speeds. 3) That it can be refueled in orbit, at a scale that has never been done before. Each Mars mission will require 8 tanker flights to top up. 4) That it can provide a robust long term life support system across the various temperature and vacuum levels to and on Mars that will work for years with only on site maintenance.

danjac 6y ago
Does the Starship design include adequate radiation shielding for the long trip in deep space?
- nickik 6y ago
  There are two types of radiation. Cosmic radiation you can't really do all that much about without making a much bigger more complex vehicle. The plan here is just to 'take it' and improve the speed of transit over time. Solar radiation is only temporary and in such cases Starship will have a 'bunker' that has good shielding. Meaning is surrounded by water and food. So long as we are talking about small crews that should be fine, large crews this needs to be thought threw more carefully.
nickik 6y ago
For the actual Mars spaceship it will likely not have dozens of reentries, that would be 20+ years of operation. The tanker or simple commercial cargo version will need to handle dozens of earth reentries. Otherwise I think your dead on with the challenges. I think the major missing one is ice mining on mars. The life support for a relatively small crew should be manageable, you can have inefficiency thanks to the absurd size. Only once you want to put 100 people in it you need to be perfect on your life management efficiency.
- valuearb 6y ago
  I skipped ice mining because the missions don’t require it as a prerequisite. The first teams on the first synod don’t have to succeed at it. They will learn what does and doesn' work. Each succeeding synod they will get closer till they finally succeed. Every synod they will get new supplies and better equipment to address the failings of the previous. And if it takes too long, they will eventually get sent tankers to supply return trips.
  - nickik 6y ago
    Without Ice mining or some way of getting water you are stuck on Mars. Its absolutely part of the core requirement. Check Elon presentation from 2016, its in there as one of the key things.
    - valuearb 6y ago
      It’s a core requirement for return flights to Earth in the “Mars Direct” model that SpaceX has based its plan on. But the SpaceX plan doesn’t require the astronaut return on the first Synod, or on any fixed schedule. The first to land will have ice mining and in situ fuel generation equipment, but we have no idea if they will work, or work at a level that will generate enough fuel for return flights in reasonable time periods. Which is fine. Succeeding missions will bring equipment to address the shortcomings of the first, until they are producing fuel effectively for return missions. The first astronauts are unlikely to be able to return in the first two years, it might take ten. But they will happily sign up for this plan because it gets them to Mars decades sooner.
bumby 6y ago
>without a lot of expensive maintenance I don’t think this can be overstated. Aerospace is notoriously expensive in large part because of its quality requirements. The amount of checks, oversight, buy-offs, traceability etc. adds enormous cost. Unfortunately, this risk increases over time because as more bad things happen there is a natural pull to add bureaucratic layers/checks to avoid the same thing happening again, eroding any previous maintenance/cost savings
LargoLasskhyfv 6y ago
Don't know anything about the Nova-level of the Saturns, never heard of that, so hypothetical to me. There existed another concept from that time frame: [1] https://en.wikipedia.org/wiki/Sea_Dragon_(rocket) https://en.wikipedia.org/wiki/Sea_Dragon_(rocket) Isn't that splashy ?

danjac 6y ago

Does the Starship design include adequate radiation shielding for the long trip in deep space?

nickik 6y ago
There are two types of radiation. Cosmic radiation you can't really do all that much about without making a much bigger more complex vehicle. The plan here is just to 'take it' and improve the speed of transit over time. Solar radiation is only temporary and in such cases Starship will have a 'bunker' that has good shielding. Meaning is surrounded by water and food. So long as we are talking about small crews that should be fine, large crews this needs to be thought threw more carefully.

nickik 6y ago

For the actual Mars spaceship it will likely not have dozens of reentries, that would be 20+ years of operation. The tanker or simple commercial cargo version will need to handle dozens of earth reentries. Otherwise I think your dead on with the challenges. I think the major missing one is ice mining on mars. The life support for a relatively small crew should be manageable, you can have inefficiency thanks to the absurd size. Only once you want to put 100 people in it you need to be perfect on your life management efficiency.

valuearb 6y ago
I skipped ice mining because the missions don’t require it as a prerequisite. The first teams on the first synod don’t have to succeed at it. They will learn what does and doesn' work. Each succeeding synod they will get closer till they finally succeed. Every synod they will get new supplies and better equipment to address the failings of the previous. And if it takes too long, they will eventually get sent tankers to supply return trips.
- nickik 6y ago
  Without Ice mining or some way of getting water you are stuck on Mars. Its absolutely part of the core requirement. Check Elon presentation from 2016, its in there as one of the key things.
  - valuearb 6y ago
    It’s a core requirement for return flights to Earth in the “Mars Direct” model that SpaceX has based its plan on. But the SpaceX plan doesn’t require the astronaut return on the first Synod, or on any fixed schedule. The first to land will have ice mining and in situ fuel generation equipment, but we have no idea if they will work, or work at a level that will generate enough fuel for return flights in reasonable time periods. Which is fine. Succeeding missions will bring equipment to address the shortcomings of the first, until they are producing fuel effectively for return missions. The first astronauts are unlikely to be able to return in the first two years, it might take ten. But they will happily sign up for this plan because it gets them to Mars decades sooner.

bumby 6y ago

>without a lot of expensive maintenance I don’t think this can be overstated. Aerospace is notoriously expensive in large part because of its quality requirements. The amount of checks, oversight, buy-offs, traceability etc. adds enormous cost. Unfortunately, this risk increases over time because as more bad things happen there is a natural pull to add bureaucratic layers/checks to avoid the same thing happening again, eroding any previous maintenance/cost savings

LargoLasskhyfv 6y ago

Don't know anything about the Nova-level of the Saturns, never heard of that, so hypothetical to me. There existed another concept from that time frame: [1] https://en.wikipedia.org/wiki/Sea_Dragon_(rocket) https://en.wikipedia.org/wiki/Sea_Dragon_(rocket) Isn't that splashy ?