Can Victorian engineers build spacecraft with an Epstein drive?

Question

During the 18th century, astronomers discovered a variable star whose variability turned out to be a coded message, describing a simple way to build a rocket engine that (somehow) has performance similar to that of the Expanse's Epstein drive. By the Victorian age, this engine and its fuel can be easily produced.

However, Victorian materials and engineering precision didn't come close to what modern technology (or even early space-age technology) can achieve. My question is: given the existence of such a rocket engine, could otherwise realistic Victorian-era technology create interplanetary spacecraft?

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Some details on the engine's performance:

• Specific Impulse: 1,100,000 seconds
• Max thrust: 1 MN
• Open cycle cooling (drive heat is carried away by the exhaust plume)

Answer 1

1.1 million seconds means an exhaust velocity of 10800 km/s, 3.6% c. Producing 1 MN of thrust at that specific impulse will mean a power output just in terms of the exhaust plume's kinetic energy of 5.4 terawatts.

Firstly, justifying a vehicle built with Victorian technology with such a drive not converting itself to glowing vapor and wreckage just due to proximity to its own exhaust plume is going to be a stretch.

Secondly, the ability to produce such an engine and some fuel to run it implies a huge variety of other capabilities that they will be much more ready to take advantage of. For example, they could use the same technology, greatly scaled down, to boil steam for steam engines without needing coal. Or, they could easily weaponize it.

Finally, this is an enormous amount of power output. Some quick number crunching suggests it'd be achievable with a very high efficiency fusion engine, but it stretches credibility for Victorian technology to be capable of creating a fusion system that not only works, but is close to the physical limits of performance. It's almost more believable if they got instructions for building some matter-annihilation engine using principles we don't even understand now.

The matter annihilation approach would also work around the exotic fuel problem of fusion power, and allow for future improvements that give even more output.

Answer 2

In terms of engineering maybe, in terms of materials no. The Victorians had the precision engineering to build a rocket engine with tight enough engineering tolerances to theoretically perform, after a fashion, (probably not tight enough for such a high performance unit though). What they didn't have was the material science to control the alloy quality of components to the point where they would perform as designed. Without this there would be extremely high component failure rates such that the engine will explode, repeatedly, in short order.

However:

All of that is pretty moot, the Victorians are several paradigm shifts away from being able to understand the object they're trying to build. If they were to build it anyway, it is possible to build complex objects that you don't understand, you'd have issues justifying the initial data transfer. You'd have to start with the extraction and refinement of elements like Titanium, Indium, Rhenium (which no-one had even isolated), Molybdenum, Ruthenium, Niobium, Tungsten etc... in industrial quantities and work from there. To give the Victorians enough information would take years, probably decades, they simply don't have the information reception technology to absorb the plans fast enough to get the project off the ground.

Answer 3

On its own, a rocket just goes. It doesn't go in a straight line, and it particularly doesn't go on the line you want it to go on. In order to control it, you need a control system that does three things: determines where it is, determines where it wants to go, and positions the rocket nozzle(s) accordingly. (It's also possible to use thrust vectoring - steering by throttling back one of your several rocket engines. Assuming you have several rocket engines. But since this is more complex in pretty much every way, it's probably not going to save you.)

None of these steps are going to be easy, or really even feasible, with Victorian technology.

Step 1 is slightly plausible, in that the fundamental tool used to determine the rocket's orientation - the gyrocompass - was invented in the Victorian era. (The tail end of it, but never mind that.) However, these were relatively large compasses designed to be used aboard ships; they were not hardened to survive the rigors of rocket launch. (In terms of acceleration and vibration, I'm not sure the Victorian era had anything comparable to the rigors of spaceflight, outside of the most powerful of natural disasters.) They were also prohibitively large and heavy for missile work. But they did exist.

Step 2 is less plausible. Once the rocket's orientation is determined, you need to compare it to the desired orientation (which changes during ascent) and then translate the difference into precise commands for each of the thruster actuators. And you have no electronics with which to do the job.

Mechanical computers did exist for solving somewhat similar (though less complex) problems in artillery. In the 1910s, there were computers that, given the range and orientation to another ship, could translate them into approximate firing solutions for the ship's guns. (But they couldn't score hits on computed solutions alone until the development of electronics and radar; considerable manual work was needed "correcting" shots.) Your mechanical computer would need to be much more precise than this, because a human trying to correct it by hand will invariably overcorrect and you will not go to space today.

It goes without saying that like the gyrocompasses, early naval firing computers weren't up to the rigor of space travel (they weren't always up to the rigors of ocean travel, in practice) and were much too large and heavy to fit on a practical rocket. So, you'd need to be much more advanced than the state of the art in multiple ways.

That gets you to step 3. Hydraulic controls are available, but will they be durable enough and accurate enough for the purpose? A few millimeters left and right can spell the difference between getting to space and getting the Range Safety Officer to press the big red button. (Oh, you don't have radar-detonated explosives? Hope you don't land anywhere important...)

Having a rocket engine, although not trivial in itself, is a far cry from having a rocket.

Answer 4

People have been able to produce precision machines for some time before the Victorian Era, and had also produced many of the materials that would be needed to build a practical spacecraft. In my estimation there were two things holding people back from going to space at the time.

First is without access to the transistor it was difficult to produce practical devices for computation and communications. There were "computers" at the time but they'd be people trained in mathematics to where they could do calculations quickly, though perhaps without precision in order to do get output quickly. There were mechanical calculators that could aid in getting calculations done quickly but they were not exactly small and light.

https://en.wikipedia.org/wiki/Arithmometer

https://en.wikipedia.org/wiki/Tide-predicting_machine

To land on the moon it took a lot of calculations to time the rockets just right for a soft landing. Part of this landing required getting an accurate distance from the moon's surface which was done by radar, and transistors were vital to getting radar to work. Some calculations had to be given to ground control since the computers on the Apollo craft would not be powerful enough to do this on their own in the time they'd be needed.

Second is without an understanding of the atom there was no power source that would be small enough to take people to space. The Apollo spacecraft didn't have a nuclear reactor but they did have radio-thermal generators that were built from materials produced in a nuclear reactor. The power density of these devices was relatively low but the energy density was high, meaning they produced a lot of energy but did so slowly.

If people were given an accurate model of the atom, and therefore an understanding of nuclear fusion and fission, then perhaps with Victorian Era manufacturing techniques people could produce nuclear rocket engines. Making something large enough and precise enough that it could launch itself into space may have been merely a matter of getting enough people motivated to produce it.

Much of what was needed to get people to the moon and back existed for centuries. New materials like artificial polymers certainly helped but there's been natural polymers known for some time, such as rubber. If people were given knowledge of nuclear fission and fusion in the Victorian Era then they may have been able to produce a fusion drive. What would remain a problem, in my opinion, would be the means to communicate without wires and the means to perform precise calculations quickly enough to navigate between planets while avoiding collisions.

Maybe the calculation problem could be solved with mechanical computers. We've seen some very elaborate computation devices built in the past, some dating back to the 2nd century BC. https://en.wikipedia.org/wiki/Antikythera_mechanism

Maybe instead of radar a means of measuring distance optically could be developed. Maybe optical communications capable of covering interplanetary distance could be developed too. Radiotelegraph communications existed after the close of the Victorian Era but if there's been a leap in technology from getting plans for a fusion propulsion rocket then moving up the development of radio and radar by a few decades would not be out of the question. With the means to produce electronics for a radio then it's a small step for analog electronic computers as a lightweight alternative to mechanical computers.

This is an interesting question and I've asked myself similar questions before. Physics didn't change so nothing really kept people from developing so many of the technologies we enjoy today at some earlier time. What was often the limiting factor was finding enough people interested in developing a technology. What often drives interest into a technology would be a hardship like war or disease. Once there's something that threatens life then people will set aside resources to get a solution quickly.

Answer 5

I see two additional problems: decoding the message, and life support

Decoding the Message

Have you ever tried to assemble a piece of flatpack furniture, following instructions translated from LOTE by a speaker of ESL? Was it not difficult, even though the author was human, with the same sort of eyes and fingers as you have? Now imagine an alien writing instructions in an alien language (Unless you make the assumptions that all highly intelligent life forms are humanoid, and speak English).

Either way, we have the problem of decrypting the message. I expect that 18th century cryptographers hadn't forgotten the techniques used a couple of centuries earlier, but they certainly weren't at the Bletchley Park level, and Bletchley Park was working with a known language. They had a German Enigma machine, that the Poles had captured; they knew the language and the format of the messages they were trying to crack; they had Alan Turing, who had also stood on the shoulders of giants; they had relay logic in their machines, later replaced with vacuum tubes; and they had all the resources that were needed to win not lose the war.

Decryption is just the first step if the message is written in an unknown language: consider the problem with Etruscan, which is, at least, a human language.

The Etruscan alphabet is similar to the Greek one. Therefore, linguists have been able to read the inscriptions in the sense of knowing roughly how they would have been pronounced, but have not yet understood their meaning.

Lack of feedback is also a problem. In my experience the first cut of the user manual for a product needs to be reviewed by users, and substantially revised. Your aliens are presumably experts in their technology, but they don't know much about how 18th century folk would interpret their message.

Life support

As @void_ptr pointed out, it's a bit awkward if our bold astronauts are DOA. You need to consider how you keep the air in, maintain oxygen levels, get rid of CO2, keep the living quarters warm (a roaring coal fire won't cut it).