The Dragon weighs less, but do you really want to put it on top of a rocket that is lit with wooden matches?
There is zero evidence that SpaceX can launch any vehicle, much less a vehicle of this size, for that amount especially given that at that price half the cost alone would be in propellants. Like nearly all of Musk’s initial claims, this is pure bombast.
Many companies and organizations over the years have attempted to reduce the major costs in space vehicle launch, that being primarily the skilled labor costs in integration, testing, and launch operations via simplification and automoation. SpaceX has attempted to do this, as well, and has actually taken a number of smart steps in this direction such as the use of horizontal integration, commonization of components, and use of built-in diagnostics in evolutions of the Falcon 9, but notably this hasn’t resulted in the projected reductions in costs even when they have worked. (SpaceX has also added complications such as propellant densification which have increased cost and delays and led to a notable catastrophic failure.).
There are certainly ways in which the conventional space launch vehicle design and processing operations could be simplified to reduce costs, but I’ll believe this claim when I see actual evidence that SpaceX is doing something truly revolutionary to achieve it. It’s really easy to draw cartoons about simplifying processes, but a lot more difficult (and requires a lot of upfront cost and effort) to make them reality.
Stranger
BFR propellant cost is under $1M. Maybe under $500k, depending.
It’s certainly true that SpaceX has a lot of work to go before achieving anywhere close to $5M flights. But they’ve been very persistent so far, pursuing such things as autonomous flight termination (in addition to the things you’ve mentioned).
I don’t think you can say that SpaceX hasn’t reduced costs. Prices have not gone down on Falcon 9, for fairly obvious reasons, but leaked docs suggest that SpaceX is highly profitable in years that their rockets aren’t exploding. 2017 was likely a very good year for them.
To my eyes, the biggest risk factor here is in the second stage. The thermal protection system was a notable weak point of the Shuttle, and SpaceX will have a lot of work to do to make their system reliable and reusable. They have enough experience with reusable boosters at this point that I think that program will go fairly smoothly, but second stage reuse is filled with a lot of unknowns.
I don’t see why not. The rocket lit with wooden matches has the distinction of being the only operating launch platform that’s actually rated for carrying humans, and has a very good record of reliability and safety. If it ain’t broke, etc.
From the OP:
That’s because there’s no detail about the ship at all. A rocket is not a spaceship. A rocket just gives a given payload a given delta-V. What that payload is is largely irrelevant for the rocket. It could be a manned capsule, or it could be a single big satellite, or it could be a bunch of small satellites. If a manned capsule, it might contain spartan accommodations for multiple astronauts, or it could contain luxurious accommodations for one. Payloads are interchangeable.
In the case of the BFR, the second stage is the ship. There’s no separate capsule.
In fact, there are three versions: a tanker (for on-orbit propellant transfer), a cargo variant with clamshell cargo bay, and a passenger ship.
There’s not a ton of detail on the ship other than that it’ll have room for around 40 cabins and 825 m[sup]3[/sup] of interior volume.
It’s likely the cargo version will come first, since it’ll serve as a Falcon 9/Heavy replacement, and just be generally easier (no man rating). The first flights to Mars will be cargo-only anyhow.
As far as the OP goes, I’ll suggest that the DC-3 is the closer analogy. It was really the first craft to open up air travel to the masses. And also like the DC-3, the BFR will, several decades from now, look quaintly small by then-contemporary standards. Rockets that small will still be flown, but most commercial flights will be on far larger ones. 1000 t or even 10000 t payloads to LEO will be the standard.
Couldn’t some kind of emergency ejection/parachute system be developed for this scenario, or are you talking about re-entry and being burned up like the Challenger was?
The Apollo program did in fact have a launch escape system for this purpose. If the rocket were to lose power or have a guidance error, the escape system could be triggered which would detach the capsule with explosive bolts and relatively small solid rocket motors. The LES was jettisoned once the craft reached orbit.
The BFR second stage is very much larger than the Apollo Command Module, and at 85 metric tons is much too large for parachute decelerators.
Stranger
The second stage won’t be able to do anything about a pad disaster. They’ll just have to demonstrate immense reliability there. The many engines on the booster stage helps a bit here; it could deal with multiple engine-outs. But pad explosion like AMOS-6 would kill everyone in the ship unless it was somehow equipped with ejection seats (never seen any claim of this).
An in-flight loss of power could lead to some interesting scenarios. Suppose the first stage loses power but not catastrophically. In principle, it could detach and fall away. But now you have a fully-fueled second stage that won’t make orbit, and doesn’t have enough thrust to land with near-full tanks. Can it dump propellant to lighten the load? Maybe it can burn inefficiently for a while before landing (just as airliners prefer to circle rather than dump fuel). Is there any chance at survivably ditching in the ocean or does it need to find land?
This also depends on the mishap being relatively benign–a serious first-stage structural failure is going to lead to a giant fireball that consumes the second stage.
It may be that the BFR is never man-rated; that for Mars/Moon missions the ship is sent up with cargo only and the humans sent on a Falcon 9/Dragon Crew (which does have a real launch escape system). Or maybe it’s only man-rated after dozens or even hundreds of flights.
Here is a rendering of the BFR in comparison to an A380
And another rendering, these are not mine, I found them on the internet.
I think what makes me convinced it will work is the simplicity of the design (No jettisoning empty orange fuel tank) And the scaling down of the ship to a more manageable level in terms of tonnage to orbit (From 500 tonnes to 150 tonnes)
I would agree with that however SpaceX has took the decision that BFR would replace all of the previous versions of the rockets it is using up until now.
But another thing to add would be the propellant production plant on Mars, what if the refinement of the fuel is not adequate?
Back in the early 90s when I did a Boeing tour they were openly talking about how they were designing the “BFA”.
Internally, aerospace workers have no problem with such an acronym.
Note that this is not the same thing as the BUFF. While first flight was 1952, not sure when the acronym became common.
There’s other less common cargo planes with a “Big F” in the nickname.
It’s not entirely clear what you are comparing to but I would infer that you are making a comparison to the American Space Transportation System (STS, colloquially referred to to as the “Space Shuttle”). If so, the yes, this concept avoids a number of problems that were inherent in the Shuttle design, not the least of which wes thr massive compound delta wings that were actually of little practical merit and severly compromised both the payload capacity and structural integrity of the Orbiter Vehicle (OV) in numerous ways. However, like the Shuttle, this vehicle would have no practical way to abort after liftoff short of Abort-To-Orbit or Return-To-Alternate-Site if it couldn’t make the desired orbit (so basically not through the bulk of its flight). This isn’t unique to the BFR; essentially any large rocket launch system without a smaller, seperable return craft with high cross range and free flight capability will have the same problem. (Ejection seats are not a practical solution; although Columbia was originally equipped with ejection seats for the pilots they were removed after the first four test flights and were never usable after the first couple dozen seconds of ascent, anyway.)
But don’t mistake the configuration simplicity of this undetailed proposal for practical simplicity in flight. There are any of a large manner of things that can potentially go wrong even with a two stage vehicle, and most failures are unrecoverable without some kind of launch ejection system that would be impractical for this size of a vehicle. And while there are many valid complaints about the complexity of the STS configuration with its parallel Solid Rocket Boosters (SRB) and the External Tank (ET), these systems performed remarkably well. The SRBs never experienced a functional failure during ascent in 135 flights (270 individual SRBs); even in the Challenger failure that was caused by hot gas jetting through a field joint, the SRB not only survived past vehicle breakup but continued to function propulsively while tumbling end over end untril intentionally terminated by the Range Safety Officer. And except for that system failure, the ET never experienced a structural failure (although ice buildup on the ET did lead to tile damage on a number of flights and critical damage to the reinforced carbon-carbon on the wing leading edge during Columbia’s last fatal return).
The real failure of the STS system was cost and turnaround time (as well as the lack of demand for its payload return capability); the original operating cost prior to final design and first flights was estimated to be around *two orders of magnitude less than the realized cost of nearly US$1B per flight, and it was assumed experience with the Shuttle would drive those costs down further with improvements in ground operations and design improvements of later fully reusable vehicles. That the STS ended up being less reliable (though in he context of launch vehicles over all, still very good) and cost far more to operate than estimated on paper is an object lesson to anyone making optimistic estimates of cost based on a paper (or in this case, digital) design.
Methane is literally the easiest hydrocarbon fuel to synthesize and because it is a gas at normal temperatures and pressures, seperating it through fractional distillation or gas centrifuge is almost trivial. However, extracting the basic elements and more importantly somehow powering the synthesis process is the greater challenge, and in-situ propellant production (ISPP) has yet to be demonstrated on any practical scale in any simulation of the Mars surface environment, or indeed, outside of terrestrial lab conditions. We don’t have to synthesize methane on Earth because it is a natural byproduct of decay and bacterial breakdown of organic material, but Mars has no natural bulk organic material (traces of various compounds have been found but not in useful quantities) and the survace environment on Mars is as inhospitable to bacteria as it will be for people.
Producing liquid oxygen is even more of a challenge; even assuming accessible subsurface water ice can be found that isn’t tightly locked in the high concentration salt brine that produce recurring slope lineae, it still remains to produce enough power to electrolytically crack water into component elements and then separate and chill liquid oxygen, or alternatively, pull carbon dioxide from the tenuous atmosphere and crack it apart at even greater energy cost, all done remotely by equipment which has to operate without maintenance for years at a time. Again, this has yet to be demonstrated in any representitive environment outside a lab on Earth and not on anything like,the scale required for ISPP.
There are, again, many very difficult problems to solve before declaring Mars open for habitation or even practical crewed exploration, and getting bulk payload to Mars orbit is the least challenging of all of them. The cartoon engineering thus far presented by SpaceX toward this aspiration does not give great confidence to anyone familiar with these problems that the capability is just around the corner even if the BFR is itself an operational success in terms of reliability and cost.
Stranger
This is kind of a weird statement in the context of ISRU methane, because the oxygen comes for free if you’re making it. It’s certainly true that CO2 and water collection are challenges, as is powering the whole enterprise and keeping your chemical reactors going. But since the Sabatier reaction requires hydrogen as a feedstock, and the only way of getting it on Mars is via water electrolysis, the oxygen comes free as a byproduct. The only further processing is purification and liquification. It’s not a significant challenge on top of what’s already necessary for methane production.
SpaceX is, apparently, working on ISRU internally but I haven’t seen any actual details on it. They’ve said that most other parts of the Mars effort will be handled by others, but they’ll handle the propellant. Not sure if that includes power, too.