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[Starver]

So, his rockets are too good, and yet his cars can't survive a quick trip to the beltway....

[wierd]

Well to be fair, the solar highway commission really DOES need to put up signs saying "Beware of flying rocks".

[smjjames]

Well to be fair, the solar highway commission really DOES need to put up signs saying "Beware of flying rocks".

lol.

apparently falcon heavy's second stage burned too long. Now projected to cruise for several months before entering the asteroid belt between mars and jupiter.

Experts believe that the intense radiation of this region will cause degredation of the organic components of both the car and the suit, and speculate that the car could literally fall apart.

Assuming we still get camera feeds and telemetry from the second stage at that location, the weathering could be interesting to record and observe.

Unless it's spinning/rotating or something, it probably won't come apart very much. Though the weathering and degredation would definetly be interesting from a scientific standpoint.

Did they say how long it would take? And unless the car was equipped with solar panels capable of working at least as far out as Mars or it has a radioactive power core, the telemetry won't last long.

Realistically though, the new rocket will definetly allow sattelites heavier than those launched now since the weight limit will be higher, which should open all sorts of opportunities. I don't know how much higher the weight limit is for the Falcon Heavy compared to the next biggest/most powerful rocket available.

I know SpaceX is planning an even more powerful rocket, dubbed the BFR (Big Falcon Rocket or, Big F'ng Rocket if you will).

[TamerVirus]

A car is in space. We only need a few more before Rainbow Road can become a reality

[RedKing]

Realistically though, the new rocket will definetly allow sattelites heavier than those launched now since the weight limit will be higher, which should open all sorts of opportunities. I don't know how much higher the weight limit is for the Falcon Heavy compared to the next biggest/most powerful rocket available.

Falcon Heavy is rated (by SpaceX) at 63,800kg payload to LEO. The next closest currently available is the Delta IV heavy, which can carry 28,790kg to LEO.

I know SpaceX is planning an even more powerful rocket, dubbed the BFR (Big Falcon Rocket or, Big F'ng Rocket if you will).

Followed by the Falcon Ginormous, Falcon Kaiju, and Falcon Super Tremendous Awesome High Power, or Falcon STAHP for short. 

Seriously though, SpaceX plans for the BFR to be able to carry 250,000kg(!!) to LEO. That's a little over half the ISS's mass. Can you imagine being able to put the ISS in orbit in two trips?

Though the stated intentions are to refuel them in orbit and then transport up to 150,000kg payloads to Mars. Musk wants to have them running cargo drops to Mars by 2022, which seems insanely ambitious.

[andrea]

The key to understand Musk timelines is understanding that his estimated on how many years projects wil take are not given in Earth years, but in Mars years. So, 7.7 earth years away from now we should see some big landing on Mars.

[Sheb]

And for further comparison, the biggest rocket ever, the Saturn V, was rated at 140,000 kg to LEO, so about twice the Falcon Heavy, but less than 60% of the BFR's intended capacity.

[Starver]

To Mars and back!

[Egan_BW]

Mars rocks!

[Trekkin]

Seriously though, SpaceX plans for the BFR to be able to carry 250,000kg(!!) to LEO. That's a little over half the ISS's mass. Can you imagine being able to put the ISS in orbit in two trips?

It's been considered before, actually, including as an option for a direct ascent Moon mission. Unfortunately, there's a size of chemical engine above which efficiency starts to drop, and banks of engines increase complexity and thus the chances of vibrational interference and simple mechanical failure. Ullage, sloshing and boil-off also get much worse as your fuel tanks get bigger.

Eventually it may well be more practical to just have the inevitable fight over nuclear space propulsion already and concentrate all the difficulty in one component (closed-cycle gas-core, ideally) rather than keep solving all the problems that crop up and worsen as rockets get bigger.

[Starver]

By coincidence, I (re)saw this, the other day: https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)

(Not on Wikipedia, but in print. Wiki's just the handiest surrogate to scanning that print thing in.)

[wierd]

Seriously though, SpaceX plans for the BFR to be able to carry 250,000kg(!!) to LEO. That's a little over half the ISS's mass. Can you imagine being able to put the ISS in orbit in two trips?

It's been considered before, actually, including as an option for a direct ascent Moon mission. Unfortunately, there's a size of chemical engine above which efficiency starts to drop, and banks of engines increase complexity and thus the chances of vibrational interference and simple mechanical failure. Ullage, sloshing and boil-off also get much worse as your fuel tanks get bigger.

Eventually it may well be more practical to just have the inevitable fight over nuclear space propulsion already and concentrate all the difficulty in one component (closed-cycle gas-core, ideally) rather than keep solving all the problems that crop up and worsen as rockets get bigger.

Parabolic mirrors + array of pulsed lasers (with final ascent stage) could also be an option.
https://en.wikipedia.org/wiki/Lightcraft

The issue is that the lightcraft prototypes need to spin like a top to sustain stability. That could be... Unsettling... to crew.  However, most cargo would be unimpacted by that.

[Trekkin]

If you can get together a proposal for ground-powered launch that doesn't have everyone conjuring the spectre of lunatics destroying the laser arrays, my hat's off to you, but for some reason the first thing everyone does when they read about space fountains or launch loops or space guns or laser launch is to suppose an infinite army of space-hating hypothetical terrorists destroying anything connected to the ground.

As for the spin problem, a contra-rotating section isn't out of the question, although it's an engineering headache.

[wierd]

To me, the obvious solution is either a combination of launch-loop or lightcraft ground based first stage ascent, with nuclear final ascent. At least if we are talking "Super heavy lift vehicle launching a colony ship or permanent space habitat" type scenario.  Those would get very infrequent launches (due to costs of building the thing to launch as well as the costs of launching it themselves), so nuclear propulsion is less of a long-term problem, especially very high up in LEO.

Would not stop the morons NIMBY types from complaining about nuclear propulsion though.  In terms of delta-v per pound it is very hard to beat old school proposal for Orion.

[Reelya]

https://science.howstuffworks.com/light-propulsion1.htm

How does the spin scale-up however? The prototype mentioned here span at 10,000 rpm but weighed only 50 grams, and this was stated to compensate for the buffeting forces of air resistance.

But the force of air resistance increases proportionally with surface area, which increases at a slower rate than volume when you evenly scale up the model. e.g. an n^3 more massive ship has n^2 the surface area, meaning only n^2 surface area to compensate for and n^3 times more mass. Additionally, an n^3 sized ship has points which average n-times further from the center, which also reduces spin-speed for the same angular momentum, by n, since angular momentum is mass x velocity x radius. So I'm guessing in idealized circumstances than an n^3 scale version would spin n^2 times slower.

e.g. if you're launching a 50-kilogram scaled-up version of the same thing perhaps 100 rpm is enough instead of 10000 rpm, though in reality you'd probably want to make the thing thinner and more missile-like meaning you don't scale up all dimensions equally, but the rpms would still be much reduced, maybe n * sqrt(n) lower for an n^3-sized ship. So, a ballpark figure for a 10^6 (n=100) sized ship - 50 metric tons might by that you only need to get it up to spinning 10 rpm to maintain stability.

Let me know if I made any errors in my assumptions here since this isn't an area I've studied in detail.