SpaceX's Big Fucking Rocket (BFR) - Making Life Multiplanetary - I'm Programmer
SpaceX's Big Fucking Rocket (BFR) - Making Life Multiplanetary - I'm Programmer

Today SpaceX introduced it’s BFR, Here are some glimpse of it.


The BFR will be capable of taking people from any city to any other city on Earth in under one hour.

MUSK ALSO PROPOSED A VARIETY OF NEW USES FOR THE SCALED-DOWN ROCKET

BFR to ISS - I'm Programmer
BFR to ISS – I’m Programmer

Moon Base Alpha

A post shared by Elon Musk (@elonmusk) on

 

MUSK’S ULTIMATE GOAL IS STILL MARS

SpaceX CEO Elon Musk unveiled revised plans to travel to the Moon and Mars at a space industry conference today.

“I think there are really two fundamental paths. History is going to bifurcate along two directions. One path is we stay on Earth forever, and then there will be some eventual extinction event. I do not have an immediate doomsday prophecy, but eventually, history suggests, there will be some doomsday event.

The alternative is to become a space-bearing civilization and a multi-planetary species, which I hope you would agree is the right way to go.” – Elon Musk

Mars City Opposite of Earth. Dawn and dusk sky are blue on Mars and day sky is red.

A post shared by Elon Musk (@elonmusk) on

Here are some more details.

System Architecture - I'm Programmer
System Architecture – I’m Programmer
Mars Entry - I'm Programmer
Mars Entry – I’m Programmer

Sometimes people wonder, “Well, what about other places in the solar system? Why Mars?” Our options for becoming a multi-planetary species within our solar system are limited. We have, in terms of nearby options, Venus, but Venus is a high-pressure—super-high-pressure—hot acid bath, so that would be a tricky one. Venus is not at all like the goddess. So, it would be really difficult to make things work on Venus.

Then, there is Mercury, but that is way too close to the sun. We could potentially go onto one of the moons of Jupiter or Saturn, but those are quite far out, much further from the sun, and much harder to get to.

It really only leaves us with one option if we want to become a multi-planetary civilization, and that is Mars. We could conceivably go to our moon, and I actually have nothing against going to the moon, but I think it is challenging to become multi-planetary on the moon because it is much smaller than a planet. It does not have any atmosphere. It is not as resource-rich as Mars. It has got a 28-day day, whereas the Mars day is 24.5 hours. In general, Mars is far better-suited ultimately to scale up to be a self-sustaining civilization.

Mars is about half as far again from the sun as Earth is, so it still has decent sunlight. It is a little cold, but we can warm it up. It has a very helpful atmosphere, which, being primarily CO2 with some nitrogen and argon and a few other trace elements, means that we can grow plants on Mars just by compressing the atmosphere.

It would be quite fun to be on Mars because you would have gravity that is about 37% of that of Earth, so you would be able to lift heavy things and bound around. Furthermore, the day is remarkably close to that of Earth. We just need to change the populations because currently we have seven billion people on Earth and none on Mars.

It is a bit tricky because we have to figure out how to improve the cost of trips to Mars by five million percent. This translates to an improvement of approximately four-and-a-half orders of magnitude. This is not easy. It sounds virtually impossible, but there are ways to do it.

These are the key elements that are needed in order to achieve the four-and-a-half orders of magnitude improvement. Most of the improvement would come from full reusability—somewhere between two and two-and-a-half orders of magnitude. The other two orders of magnitude would come from refilling in orbit, propellant production on Mars, and choosing the right propellant.

Full reusability

To make Mars trips possible on a large enough scale to create a self-sustaining city, full reusability is essential. Full reusability is really the super-hard one. It is very difficult to achieve reusability even for an orbital system, and that challenge becomes substantially greater for a system that has to go to another planet.

You could use any form of transport as an example of the difference between reusability and expendability in aircraft. A car, bicycle, horse, if they were single-use—almost no one would use them; it would be too expensive. However, with frequent flights, you can take an aircraft that costs $90 million and buy a ticket on Southwest right now from Los Angeles to Vegas for $43, including taxes. If it were single use, it would cost $500,000 per flight. Right there, you can see an improvement of four orders of magnitude.

Now, this is harder—reusability does not apply quite as much to Mars because the number of times that you can reuse the spaceship pod of the system is less often because the Earth–Mars rendezvous only occurs every 26 months. Therefore, you get to use the spaceship part approximately every 2 years.

Refilling in orbit

You would get to use the booster and the tanker frequently. Therefore, it makes sense to load the spaceship into orbit with essentially tanks dry. If it has really big tanks that you use the booster and tanker to refill once in orbit, you can maximize the payload of the spaceship, so when it goes to Mars, you have a very large payload capability.

Hence, refilling in orbit is one of the essential elements of this (Table 2). Without refilling in orbit, you would have roughly a half order of magnitude impact on the cost. What that means is that each order of magnitude is a factor of 10. Therefore, not refilling in orbit would mean roughly a 500% increase in the cost per ticket.

It also allows us to build a smaller vehicle and lower the development cost, although this is still quite big. However, it would be much harder to build something that is 5–10 times the size.

Furthermore, it reduces the sensitivity of the performance characteristics of the booster rocket and tanker. So, if there is a shortfall in the performance of any of the elements, you can make up for it by having one or two extra refilling trips to the spaceship. This is very important for reducing the susceptibility of the system to a performance shortfall.

Propellant production on Mars

Producing propellant on Mars is obviously also very important (Table 3). Again, if we did not do this, it would have at least a half order of magnitude increase in the cost of a trip. It would be pretty absurd to try to build a city on Mars if your spaceships just stayed on Mars and did not go back to Earth. You would have a massive graveyard of ships; you have to do something with them.

ISRU - I'm Programmer
ISRU – I’m Programmer

It would not really make sense to leave your spaceships on Mars; you would want to build a propellant plant on Mars and send the ships back. Mars happens to work out well for that because it has a CO2 atmosphere, it has water-ice in the soil, and with H2O and CO2, you can produce methane (CH4) and oxygen (O2).

Right propellant

Picking the right propellant is also important. There are three main choices, and they each have their merits. First, there is kerosene, or rocket propellant-grade kerosene, essentially a highly refined form of jet fuel. It helps keep the vehicle size small, but because it is a very specialized form of jet fuel, it is quite expensive. Its reusability potential is lower. It would be very difficult to make this on Mars because there is no oil. Propellant transfer is pretty good but not great.

Hydrogen, although it has a high specific impulse, is very expensive, and it is incredibly difficult to keep from boiling off because liquid hydrogen is very close to absolute zero as a liquid. Therefore, the installation required is tremendous, and the energy cost on Mars of producing and storing hydrogen would be very high.

Therefore, when we looked at the overall system optimization, it was clear that methane was the clear winner. Methane would require from 50% to 60% of the energy on Mars to refill propellant using the propellant depot, and the technical challenges are a lot easier. We therefore think methane is better almost across the board.

We started off initially thinking that hydrogen would make sense, but ultimately came to the conclusion that the best way to optimize the cost-per-unit mass to Mars and back is to use an all-methane system—or technically, deep-cryo methalox.

Whatever system is designed, whether by SpaceX or someone else, these are the four features that need to be addressed in order for the system really to achieve a low cost per ton to the surface of Mars.

Raptor Engine

We started the development with what are probably the two most difficult key elements of the design of the interplanetary spaceship, the engine and rocket booster. The Raptor engine is going to be the highest chamber pressure engine of any kind ever built, and probably the highest thrust-to-weight.

Raptor Engine - I'm Programmer
Raptor Engine – I’m Programmer

It is a full-flow staged combustion engine, which maximizes the theoretical momentum that you can get out of a given source fuel and oxidizer. We subcool the oxygen and methane to densify it. Compared with when used close to their boiling points in most rockets, in our case, we load the propellants close to their freezing point. That can result in a density improvement of around 10%–12%, which makes an enormous difference in the actual result of the rocket. It gets rid of any cavitation risk for the turbo pumps, and it makes it easier to feed a high-pressure turbo pump if you have very cold propellant.

One of the keys here, though, is the vacuum version of the Raptor having a 382-second ISP. This is critical to the whole Mars mission and we are confident we can get to that number or at least within a few seconds of that number, ultimately maybe even exceeding it slightly.

Rocket Booster

In many ways, the rocket booster is really a scaled-up version of the Falcon 9 booster. There are a lot of similarities, such as the grid fins and clustering a lot of engines at the base. The big differences are that the primary structure is an advanced form of carbon fiber as opposed to aluminum lithium, we use autogenous pressurization, and we get rid of the helium and the nitrogen.It is a lot of engines, but with Falcon Heavy, which should launch early next year, there are 27 engines on the base. Therefore, we have considerable experience with a large number of engines. It also gives us redundancy so that if some of the engines fail, you can still continue the mission and everything will be fine.

Rocket Booster - I'm Programmer
Rocket Booster – I’m Programmer

However, the main job of the booster is to accelerate the spaceship to around 8,500 km/h. For those who are less familiar with orbital dynamics, it is all about velocity and not about height.

In the case of other planets, though, which have a gravity well that is not as deep, such as Mars, the moons of Jupiter, conceivably one day maybe even Venus—well, Venus will be a little trickier—but for most of the solar system, you only need the spaceship. You do not need the booster if you have a lower gravity well. Therefore, no booster is needed on the moon or Mars or any of the moons of Jupiter or Pluto. The booster is just there for heavy gravity wells.

We have also been able to optimize the propellant needed for boost back and landing to get it down to about 7% of the lift-off propellant load. With some optimization, maybe we can get it down to about 6%.

We are also now getting quite comfortable with the accuracy of the landing. If you have been watching the Falcon 9 landings, you will see that they are getting increasingly closer to the bull’s eye. In particular, with the addition of maneuvering thrusters, we think we can actually put the booster right back on the launch stand. Then, those fins at the base are essentially centering features to take out any minor position mismatch at the launch site.

So, that is what it looks like at the base. We think we only need to gimbal or steer the center cluster of engines. There are seven engines in the center cluster. Those would be the ones that move for steering the rocket, and the other ones would be fixed in position. We can max out the number of engines because we do not have to leave any room for gimbaling or moving the engines. This is all designed so that you could actually lose multiple engines, even at lift-off or anywhere in flight, and still continue the mission safely.

Propellant Plant

The ingredients are there on Mars to create a propellant plant with relative ease because the atmosphere is primarily CO2, and water-ice is almost everywhere. There is CO2 plus H2O to make methane, CH4, and oxygen, O2, using the Sabatier reaction. The trickiest thing really is the energy source, which can be done with a large field of solar panels

Cost Per Trip

The key is making this affordable to almost anyone who wants to go. Based on this architecture, assuming optimization over time, we are looking at a cost per ticket of <$200,000, maybe as little as $100,000 over time, depending upon how much mass a person takes.

Cost to Mars - I'm Programmer
Cost to Mars – I’m Programmer

Right now, we are estimating about $140,000 per ton for the trips to Mars. If a person plus their luggage is less than that, taking into account food consumption and life support, the cost of moving to Mars could ultimately drop below $100,000.

Obviously, it is going to be a challenge to fund this whole endeavor. We expect to generate a pretty decent net cash flow from launching lots of satellites and servicing the space station for NASA, transferring cargo to and from the space station.

There are also many people in the private sector who are interested in helping to fund a base on Mars, and perhaps there will be interest on the government sector side to do that too. Ultimately, this is going to be a huge public–private partnership.

Right now, we are just trying to make as much progress as we can with the resources that we have available and to keep the ball moving forward. As we show that this is possible and that this dream is real—it is not just a dream, it is something that can be made real—the support will snowball over time.

I should also add that the main reason I am personally accumulating assets is in order to fund this. I really do not have any other motivation for personally accumulating assets except to be able to make the biggest contribution I can to making life multi-planetary.

Timeline for future

TimeLine - I'm Programmer
TimeLine – I’m Programmer

We were intentionally fuzzy about this timeline. However, we are going to try to make as much progress as we can on a very constrained budget, on the elements of the interplanetary transport booster and spaceship. Hopefully, we will be able to complete the first development spaceship in maybe about 4 years, and we will start doing suborbital flights with that.

In 2016, we also demonstrated landing on a ship, which is important for both the very high-velocity geosynchronous missions and for the reusability of Falcon 9 because about roughly a quarter of our missions service the space station. There are a few other lower-orbit missions, but probably 60% of our missions are commercial GEO missions. These high-velocity missions need to land on a ship out at sea. They do not have enough propellant onboard to boost back to the launch site.

It has enough capability that you could possibly go to orbit if you limit the amount of cargo on the spaceship. You would have to really strip it down, but in tanker form, it could definitely get to orbit. It cannot get back, but it can get to orbit.

Maybe there is some market for the really fast transport of things around the world, provided we can land somewhere where noise is not a super-big deal because rockets are very noisy. We could transport cargo to anywhere on Earth in 45 minutes at the most. Hence, most places on Earth would be 20–25 minutes away. If we had a floating platform off the coast of New York, 20–30 miles out, you could go from New York to Tokyo in 25 minutes and across the Atlantic in 10 minutes. Most of your time would be spent getting to the ship, and then it would be very quick after that. Therefore, there are some intriguing possibilities there, although we are not counting on that.

Then, there is the development of the booster. The booster part is relatively straightforward because it amounts to a scaling up of the Falcon 9 booster. So, we do not see that there will be many showstoppers there.

Then it will be a case of trying to put it all together and make this actually work for Mars. If things go super-well, it might be in the 10-year timeframe, but I do not want to say that is when it will occur. There is a huge amount of risk. It is going to cost a lot. There is a good chance we will not succeed, but we are going to do our best and try to make as much progress as possible.

Beyond Mars

What about beyond Mars? As we thought about the system and the reason we call it a system—because generally, I do not like calling things “systems,” as everything is a system, including your dog. However, it is actually more than a vehicle. There is obviously the rocket booster, the spaceship, the tanker and the propellant plant, and the in situ propellant production.

Jupiter - I'm programmer
Jupiter – I’m programmer

If you have all four of these elements, you can go anywhere in the solar system by planet hopping or moon hopping. By establishing a propellant depot on the asteroid belt or on one of the moons of Jupiter, you can make flights from Mars to Jupiter. In fact, even without a propellant depot at Mars, you can do a flyby of Jupiter.

However, by establishing a propellant depot, say on Enceladus or Europa, and then establishing another one on Titan, Saturn’s moon, and then perhaps another one further out on Pluto or elsewhere in the solar system, this system really gives you the freedom to go anywhere you want in the greater solar system.

Enceladus- I'm programmer
Enceladus- I’m programmer
Europa- I'm programmer
Europa- I’m programmer
Flyby of Saturn. - I'm programmer
Flyby of Saturn. – I’m programmer

 

Therefore, you could travel out to the Kuiper Belt, to the Oort cloud. I would not recommend this for interstellar journeys, but this basic system—provided we have filling stations along the way—means full access to the entire greater solar system.