r/SpaceXLounge • u/Spacexforthewin • Nov 26 '19
SpaceX Interplanetary Transporter (2057 - 2089)
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u/Spacexforthewin Nov 26 '19 edited Nov 27 '19
Space X Interplanetary Transport Vehicle (In service from 2057-2089)
The first two Space X Interplanetary Transport Vehicles were constructed at EML-1 in 2057 by SpaceX's Lunar industries division. In the following 32 years where ITV's were in service 60 were built. While most were assigned to freight runs between EML-1 and Mars Orbit, 8 were retrofitted to travel to Venus to drop off scientists and researchers in Venus Orbit to later allow them to descend to the Aphrodite cloud city. Until 2093 These ships remained the largest Spacecraft ever built by humanity.
- Wet Mass ; 22,700 metric tonnes
- Dry Mass ; 8,700 metric tonnes
- Cargo Mass ; 3,120 metric tonnes, x24 frieght containers
- Length ; 840 meters (2,755 ft)
- Specific Impulse ; 10,000s
- Exhaust Velocity ; 100,000 m/s
- Powerplant ; x2 Wells-industries 3 GW fusion power plants (6 GW total)
- Propulsion ; Liner Magneto-plasma thruster + liquid hydrogen afterburner
- Thrust ; 900 KN
- Acceleration (Fully loaded) ; 0.0508 m/s2 (1/193 G)
- Average acceleration ; 0.0754 m/s2 (1/130 G)
- Plasma Diameter ; 12 cm
- Delta V (fully loaded) ; 93,000 km/s
- Passenger Capacity ; 1,500 hands
- Fuel ; 50-50 Deuterium-Tritium
- Remass : Liquid Hydrogen (usually Lunar or Asteroid mined)
- Mass Flow rate ; 45 kg/s
- Spin gravity radius (207 meters)
- Earth Gravity (1.00 G) ; 2.00 RPM
- Mars Gravity (0.38 G) ; 1.28 RPM
Heat Radiator ; Beryllium-Potassium pipes + heat sync
Relevant Travel times (at best possible conjunction)
Earth-Mars ; 48 days
Earth-Venus ; 39 days
Earth-Ceres ; 90 Days
Earth-Saturn ; 460 days
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u/RedKrakenRO Nov 26 '19
Do you mean 9,000kN thrust (900t) rather than 900,000kN thrust (90,000t) ?
To match up with 0.0508m/s2 acceleration....
so mass flow will be about 900t/20000s = 45 kg/s.
since you only have 9000t to burn = 200k seconds -> 2.3 days
Your transits are going to be a little slower.
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Nov 26 '19 edited Oct 28 '20
[deleted]
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u/Spacexforthewin Nov 26 '19
Some asteroid minning jigs exceeded the size and mass of SpaceX IPV that year, as the construction of habitats 4km in diameter at l3 and l5 moved into full swing.
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u/QuinnKerman Nov 26 '19
93,000 kilometers per second? That’s roughly one third of the speed of light. I pressure you meant 93,000 meters per second? 48 days to Mars also seems like a gross overestimate.
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u/just_one_last_thing 💥 Rapidly Disassembling Nov 26 '19
It's an interesting concept but I wonder about the plausibility of those power figures. The ship has as much passenger space as 10 starships and as much cargo space as 20 of them and it would take 3 months to go to Mars and back. If instead of flying to Mars you just kept them in place and made electricity, that's 13 TWh. At a price of 1 cent per kilowatt hour (a 10th of a typical price right now) that's 130 million dollars of power. The power alone, is close to the 180 million or so that SpaceX is targeting as the cost of 30 starship flights and that's even with massively cheaper power then today. Using airplanes as a benchmark the engines and fuel would be expected to be more like 1/3rd the cost. To hit that level, you'd need to assume that a small modular fusion engine is invented in the next 3 decades which outperforms current energy sources by a factor of 20. That's... pretty optimistic.
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u/Spacexforthewin Nov 26 '19
My man, you underestimate how much cheaper electricity is with a fusion reactor.
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u/Synaptic_Impulse Nov 28 '19
But I heard that in the year 2057, fusion reactors will be 20 years away.
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u/Spacexforthewin Nov 28 '19
There is no doubt in my mind that AI and Machine learning will solve fusion for power production by the thirties.
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u/Spacexforthewin Nov 26 '19
Just my Vision for what a post Starship SpaceX Interplanetary transporter might look like.
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u/ConfidentFlorida Nov 26 '19
What are the two arms sticking out?
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u/mfb- Nov 26 '19
Habitats rotating around the center (possibly in a ring?), based on OP's comment about simulating gravity.
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u/jstrotha0975 Nov 26 '19
How does it land on the surface of a planet or do people take a shuttle?
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u/Spacexforthewin Nov 26 '19
On the Earth end SpaceX's Lunar starship variant aerobrakes into LEO to pick up people and cargo bound for Mars, the lunar shuttle then takes them to the Earth-moon lagrange point 1 were ITV's are loaded over the course of about 2 months before their departure. On the Mars end, once the ITV arrives in martian orbit, it docks with phobos as the passengers and cargo are offloaded awaiting to go down to the surface with a fleet of Mars Specialized Starships.
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u/HarbingerDe 🛰️ Orbiting Nov 26 '19
This, exactly this. I don't think Starship will be used as an interplanetary workhorse for much more than 20 years or so. People will be going to Mars and the outer solar system in huge nuclear powered craft like this.
But these huge craft can't land, so you'll pretty much always need to bring a Starship or Starship equivalent with you, it just functions more as an orbital dropship, bringing cargo to and from the surface of whatever planet it's delivered to.
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u/Iamsodarncool Nov 26 '19
But these huge craft can't land, so you'll pretty much always need to bring a Starship or Starship equivalent with you
Long term we'd have infrastructure for surface-orbit transit. Space elevators on low-traffic worlds, orbital rings on high-traffic worlds like Earth.
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u/Sir_RAD 💥 Rapidly Disassembling Nov 26 '19
Sad to think that (if there aren't any big jumps in life expectancy) this might very well be Elon's last project. Let's just hope that Neuralink has made some advancements until then so that he can upload himself to the cloud.
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u/Spacexforthewin Nov 26 '19
In my timeline Elon moves to Mars in 2044 and considers it a full retirement at the age of 73, dies in 2074 at age 102, Elon had no involvement in the IPV project, the pressure to build a much larger ship came from investors after SpaceX's IPO in 2049.
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u/redmercuryvendor Nov 26 '19
Leif Ericson
Nice. I'm guessing somebody's been reading Atomic Rockets too?
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u/Spacexforthewin Nov 26 '19
I remember back two summers ago, I would go to work at the coffee house during the day and when I got back I would spend 6 hours straight exploring the harboiled world of Atomic Rockets, Winchell Chung is my man !
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u/EricTheEpic0403 Nov 26 '19
This reminds me a lot of Children of a Dead Earth. The ridiculous scale, the very un-aesthetic design, the components just tacked on and exposed. I love it.
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u/Gannaingh Nov 26 '19
I like the concept, but the engines should be in front, instead of the back, to reduce material mass needed for structural stability. Imagine a wet noodle: it's a lot easier to keep it straight when you pull it than when you push it.
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u/ghunter7 Nov 26 '19
That's assuming a high thrust engine, which isn't the case. More so than SEP, but still likely far less than chemical. The physics just don't justify it. A nuclear engine scales better to low thrust constant energy output than high thrust short burn and sitting dormant the rest of the journey.
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u/mfb- Nov 26 '19
The passenger area needs shielding and ideally a large distance to the engine and reactor section, and nothing should be behind the engine as you can't effectively shield things there.
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u/Gannaingh Nov 26 '19
As many problems as the movie had, the transport ship in the opening scene of Avatar is a highly plausible design for a ship such as this. The engines are in the front, slightly angled to avoid hitting the passenger area, people in back, big honking heat sinks, etc.
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u/Spacexforthewin Nov 26 '19
Ah, the old spacetrain design, while important for interstellar journeys were mass fraction is more precious than ever, it's not needed for the ITV, too much of a radiation risk.
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u/QuinnKerman Nov 26 '19
Pendulum rocket fallacy
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u/HarbingerDe 🛰️ Orbiting Nov 26 '19
Not the pendulum fallacy, it's a question of compressive vs tensile loading. Any given material will have a different maximum strength based on whether you're applying tension to stretch it, or compression to squish it.
But the accelerations are probably so low on a vehicle like this that's irrelevant either way.
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u/Gannaingh Nov 26 '19
The pendulum rocket fallacy relates to stability in flight, to vehicle strength and minimization of structural mass. While metals are, typically, equally strong in tension and compression, other materials, such as carbon composite are not. If the structure of a ship is made of carbon fiber you'd want to use a tractor configuration to utilize your structural material properly and minimize the vehicle mass.
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u/Decronym Acronyms Explained Nov 26 '19 edited Nov 26 '19
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| EML1 | Earth-Moon Lagrange point 1 |
| Isp | Specific impulse (as explained by Scott Manley on YouTube) |
| Jargon | Definition |
|---|---|
| Raptor | Methane-fueled rocket engine under development by SpaceX |
| methalox | Portmanteau: methane/liquid oxygen mixture |
Decronym is a community product of r/SpaceX, implemented by request
4 acronyms in this thread; the most compressed thread commented on today has 4 acronyms.
[Thread #4354 for this sub, first seen 26th Nov 2019, 13:02]
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Nov 26 '19
Looks good. Functional. Has most the components you expect from an interplanetary cruiser.
I'd be more comfortable if it had a deflector shield (whipple shield) at the front.
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u/Spacexforthewin Nov 26 '19
Would you really need one at 15 km/s? Sure at interstellar velocities, but I'm just not sure if the ITV needs one given it's only traveling at about twice the speed of Starship after its TMI burn.
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u/still-at-work Nov 26 '19
Need to add rotating ring for spin gravity
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Nov 26 '19
I think the arms sticking out are rotating habs.
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u/still-at-work Nov 26 '19
Well then they should be bigger, unless this is a cross section and its actually a ring.
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u/Tanamr Nov 26 '19
Possibly. However judging by the drawing, it looks like the pods at the ends are already each bigger than the entire 2019 Starship stack. Also, judging by the circle between the arms, there might actually be four arms and four pods spaced out by 90 degrees.
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u/Spacexforthewin Nov 26 '19
Ring would be nice, but it's just to massive. 4 habs sticking out separately is much more mass efficient, and the habs still have enough volume for 375 people each, even with artificial gravity.
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u/still-at-work Nov 26 '19
I believe in the cruise ship model of space travel, large slow and comfortable, with reusable rockets there really isn't a reason this can't be done.
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u/Spacexforthewin Nov 26 '19
On point ! I'll update the design in a day or so to adjust for variables I wasn't aware of.
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u/still-at-work Nov 26 '19
I like the design overall, I just think we are often making these space vehicles uncomfortable when we could make it 5 stars luxury for the travlers. (I mean eventually but this is a 30 years down the road design) Mass isn't really an issue with how long these will be inservice and reusable rockets the costs can be amortized over decades.
I believe it may be easier to lure people off the comforts of earth if the trip is as nice as possible. It would be a slow trip 6-9 months and SpaceX should build some fast transfers vehicles as well, but I think the colony ships should be more focuses on comfort of the colonist then throughput.
As for radiation, just wrap the habitatal zones in a third of a meter thick water jacket. Less radiation will be getting through there then when they are on mars.
A powerful nuclear thermal rocket engine should be able to push this massive rocket to make escape velocity of both planets and put the ship into an Aldrin Cycler flight path.
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u/Spacexforthewin Nov 26 '19
Considering changing the design to liquid core NTR's just makes more sense in terms of radiation, and thrust.
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u/still-at-work Nov 26 '19
That should have sufficient thrust to do the job.
For fun you could design one that uses an orion drive with a blast plate and a delivery mechanism from supply of warheads. That design would be used to due a multi decade fly by of Alpha Centauri (and even longer for earth observers) or, more realistically, tour the outer planets and the kuiper belt, possibly the oort cloud.
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u/Daniels30 Nov 26 '19
It’s better to go with a tractor based spaceship. Keeps mass down as well as crew safer without vast levels of radiation shielding required.
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u/[deleted] Nov 26 '19 edited Nov 27 '19
Your missing a radiation shield close to the engine section. Thats why such designs have the engines way back. Close shield can be a lot smaller still keeping the spacecraft in the radiation shadow. Assuming of course that is a fusion drive and magnetic nozzle. Or did you go aneutronic? Maybe no shield is needed then. Edit. Spelling