Rockets need to eject particles to generate force. And to eject 1 kg of fuel, its photo synthesis system has to lose 1 km of mass in one way or another.
The solution is to find a way to generate thrust without rocket fuel ejection.
And you need quite a bit of it: even fairly small spacecraft like probes can have nearly a tonne of the stuff. Which, considering there's only 30-40ish tonnes extracted per year at a cost of about 1.5ish dollars per gram is quite a bit!
There's been a number of pure electric propulsion proposals or prototypes, but they've all turned out to be a hoax; the latest one I recall was the EmDrive [0], where any paper claiming it produced positive thrust was debunked with the measurements having been influenced by outside forces.
The TL;DR is that reactionless drives are not possible due to Newton's third law. This page / this website is always a great resource for things like this, it's in the context of writing science fiction but it has tons of research: [1]
[0] https://en.wikipedia.org/wiki/EmDrive
[1] https://www.projectrho.com/public_html/rocket/reactionlessdr...
Solar sails are probably more practical.
Gather interstellar hydrogen, use it to run a fusion engine for propulsion and power. :)
Star Trek assumed that all warp class vehicles would require them for operation and in-situ fuel replenishment.
At best we'll be able to send out probes. Maybe, but this still feels science fiction too, we can harness quantum entanglement for long distance instant communication.
This is silly, but also begs the sillier question why we aren't bioengineering plants to produce rocket fuel
Mythbusters: https://youtu.be/QEX1YFXYTdI
TopGear: https://youtu.be/GOFbsaNeZps
I suggest travelling around the world a bit and visiting ie Borneo how entire rainforest ecosystem is being reduced to nothing just due to palm oil plantations, mostly for biofuel and cheap&bad for health food additive.
Similar sight across many places out there. What you wrote ain't valid for a single one.
I'm sure the economics don't work out for it: solar panels are already cheap, the land could grow other crops, etc. But photosynthesis being lower-yield than photovoltaic generation isn't enough to rule it out. Perhaps as science fiction, on a future mission to an Earthlike planet that doesn't have the right resources to produce semiconductors at scale.
growing the fuel plant is probably easy.
How do you get it OUT of the plant?
Solar panels just sit there (they do need cleaning i admit) and produce electricity that we can manipulate very cheaply already.
What machine collects diesel from plants? Can you safely dispose of the plant matter?
False dichotomy. There are places where food does not grow at all and can be used to grow fuel crops. Say, the ocean.
Making and then using „diesel trees” would definitely require special equipment and manufacturing pipelines that might be the same cost or more than those for solar panels.
https://en.wikipedia.org/wiki/Wood_gas
It's wildly inefficient though and not worth the trouble compared to solar panels and batteries.
Measured how? If nothing else, they seem to be good at carbon capture. And I don't see how you it could account for engineered for plants engineered to store more of their energy as oil.
"Ecologically informed solar enables a sustainable energy transition in US croplands"
https://www.pnas.org/doi/full/10.1073/pnas.2501605122
As a rough estimate, you'd lose 2/3 of that energy if the electricity had to be turned into liquid fuels. That would still mean 10 times greater usable energy produced per acre.
Plants genetically engineered for fuel production might be somewhat more efficient in the future, but future solar farms are also probably going to be more efficient.
I'm sorry, were they measuring the carbon footprint of growing algae by what it takes to grow it inside with artificial light?
The only real issue with Ethanol IMO is that corn Ethanol is preventing progress in advanced synthesis made out of, ex: switchgrass cellulose. There are better sources of ethanol if we invest into them.
I don't think any food crisis scenario in the US involves a road bump that spans a single year and doesn't disrupt existing crops.
edit: Looked it up - Rice has the highest number of calories per square metre of farmland, just that it requires marshy/swamp land to grow.
Stupidest possible thing to do with food. Especially since in some operations you put in more diesel than take ethanol out.
If we need infrastructure to make use of energy we can ‘magic’ it up.
Our digestive systems heat and oxidize hydrocarbons to generate kinetic energy? You sure about that?
Of glucose, not a hydrocarbon, but there are plenty of organisms that use hydrocarbons directly.
We don't because we use glucose as our easily transportable fuel, which we evolved because plants happened to produce glucose when we evolved. If there were plants producing some hydrocarbon in fruits we'd have evolved mitochondria to use that instead.
https://www.ers.usda.gov/publications/pub-details?pubid=1057...
It doesn't make economic and enviromental sense in most parts of the world (especially corn). In some places they are net-positive on carbon emissions compared to oil-derived gasoline. Tilling the fields, growing, harvesting, processing and transporting often emits more CO2 than the equivalent gasoline produced. Especially the initial tilling of the land to convert it to farmland releases A LOT of CO2 into the atmosphere (this is a one-time thing though).
In the US all (ground vehicle) gasoline sold needs to have 10% ethanol (corn-based), in Brazil it is 20% (sugar cane based). In Brazil almost all cars support 100% ethanol fuel and it is quite common to fuel with ethanol only.
https://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil
The whole bio-fuel industry is a very complex mix of economics (often requires subsidies to make sense), geopolitical (less imported oil), environmental concerns (mass scale farming soil degradation and CO2 emissions derived from it) and logistical (completely different transportation and refining process).
Fun fact ethanol freezes at a fairly high temperature and mixes with water which makes it not ideal for cold climates and boats. It is quite common for unaware boat owners to f-up their engines by buying car-grade fuel-station gasoline in Brazil.
Alternatively, you can break it down into ethanol, which has been used as liquid rocket fuel since at least the first half of the '40s.
This classic book tells the story of liquid rocket fuel development
https://library.sciencemadness.org/library/books/ignition.pd...
You'd think that you could mix any of a wide range of fuels with a wide range of oxidizers and get a good rocket fuel but it does not really work that way, most combinations are pretty awful, including the ethanol + O2 used in the V2. There was a time when there was interest in "storable" liquid propellants but once solid propellants reached this level of maturity
https://en.wikipedia.org/wiki/LGM-30_Minuteman
those were obsolete.
It is hard to beat H2+oxygen or hydrocarbons+oxygen if you pick the right hydrocarbons (rocket kerosene isn't quite the kerosene you use in a lamp)
I'm not sure if ethylene is really that good of a rocket fuel. In the context of a space economy I see it as a "reactive carbon" substance which is easy to make other things out of, say,
https://en.wikipedia.org/wiki/Polyethylene
in the sense that glucose is reactive carbon you can build structural carbohydrates and all sorts of biological molecules out of. There is talk about SpaceX establishing a methane economy on Mars, methane is definitely an easy to synthesize rocket fuel but it not very reactive and not on the path to making other things you might want.
Sort of early 'RoundUp' with high contents of Sodium chlorate combined with powdered sugar. Very dangerous! But fun :-)
Even more fun, but potentially fatal very fast would be Potassium chlorate.
But I've been cautious, and limited myself to selfmade blackpowder mostly, during the times one 'did that' as young boys with toys.
Still have all my fingers, no burn scars, full eyesight & hearing, though. Phew! :-)
Cyanobacteria that can exist in the vacuum of space AND produce oxygen... just not fast enough to be useful, but one day, a big hairy space ship will rule the universe!
See: https://www.reddit.com/r/space/comments/1acqxml/lichen_survi...
In a more serious response almost all questions like yours can boil down to economics. You can be certain if there is a way make something at a profit someone will jump in and make it happen. If there is no money in it you can expect that even if it is more environmentally friendly it may be part of research but not going to be implemented unless it becomes profitable.
(I say this in the friendly spirit of a long-defeated fellow pedant who has hit people with your exact comment for decades)
For now and the near future there are no ways of doing that part otherwise than by using living plants or fungi, possibly with genome modifications.
The part with capturing solar light and splitting water and reducing carbon dioxide to a very simple carbon compound can be done with artificial means much more efficiently than in plants, so there is little doubt that this will become commonly used in the near future.
Ethylene or methane are good for fuel or for making plastic, but when a slightly more complex organic substance were made, e.g. glycine or glycerol, that could be used to feed a culture of fungi, which could be used to make human food, especially if genetically-modified to make higher quality proteins.
Plants are self-assembling albeit inefficient photosynthesises.
On earth, where they can harvest their carbon in situ, that inefficiency outweighed by us not having to make them. Their main components by wet and dry mass, carbon and oxygen, are dissolved in atmosphere. In space, on the other hand, the major cost is lifting. (Even earth, farming quickly becomes uneconomical when just water costs balloon.)
In space you’re moving all the mass the plant is built out of at exorbitant cost. At that point, you might as well just assemble the machinery on the ground and get the efficiency boost.
I can only see an exception arising if lifting costs start scaling with volume more than mass, i.e. post chemical rocketry, at which point sending up compacted carbon and water and letting plants assemble themselves in space makes more sense than sending up panels and tiny labs. (That or you’re going somewhere with accessible carbon and/or oxygen.)
monster_truck•14h ago
There is exceptionally little material info in this article and so very much speculation
nashashmi•13h ago
grues-dinner•13h ago
nosignono•13h ago
Americans don't like the idea that maybe China is actually rocketing past them technologically and infrastructurally, so news doesn't really report on it much.
hopelite•12h ago
I personally have nothing against the Chinese and respect them being oddly far more interested in the wellbeing of their own people than remotely anything in any western country, but it sure is odd behavior by people who consider China a threat.
“China’s an enemy” … “let’s bring in 600,000 Chinese every single year to learn from us and take the knowledge back to China and the ones that remain will be embedded spies like the people of other foreign nations who have burrowed into America and its power structure”.
VoidWhisperer•10h ago
[0]: https://www.icij.org/investigations/china-targets/china-tran...
[1]: https://www.airuniversity.af.edu/JIPA/Display/Article/358765...
[2]: https://www.cfr.org/in-brief/peng-shuai-china-disappeared-ho...
jajko•5h ago
I wouldnt take my family to a trip to US these days for example, no such issue with China. One sample aspect, a very practical one too, but there are many others.
somenameforme•3h ago
US Incarceration Rate: 541 per 100k
Chinese Incarceration Rate: 119 per 100k
It leads to the amusing outcome that the US has more people incarcerated than China, in spite of China having 4x the population of the US. It's entirely possible to criticize the Chinese system without resorting to disinformation, but as you allude to, those critiques probably hit a bit too close to home. It's akin to how the Wiki page on authoritarianism [1] has been radically shifted over time to the point that "modern" definition and the definition of 20 years ago [2] are completely different. Yet the old definition is the one that literally everybody uses, but it, again, hits a bit too close to home.
[1] - https://en.wikipedia.org/wiki/Authoritarianism
[2] - https://en.wikipedia.org/w/index.php?title=Authoritarianism&...
themafia•10h ago
The prevailing narrative, particularly around hacker news, is that China is a dangerous foe and it's technological progress is a sign that we need to give our own government more money and less oversight so that we don't lose our "technological advantage."
> Americans don't like the idea that maybe China is actually rocketing past them technologically and infrastructurally
I don't buy this explanation given it's value to American propagandists. American society is naturally competitive. There's only two likely reasons why it doesn't get reported.
It's either not as true as the Chinese would like you to believe or American industry is already profiting off of it.
kccqzy•9h ago
eunos•36m ago
aDyslecticCrow•5h ago
Its also needlessly complicated to send the experiment to space. It would be equally valid science if made on earth. So there is a clear performance in the experiment not justifiable by any scientific reason.
Not to say china isn't ahead in space development right now. Artemis is going quite badly and china could certainly be faster to building usable moon outpost.
Its also very cool science, if its claims are true.
somenameforme•3h ago
> "Artemis is going..."
That's quite optimistic.
[1] - https://english.news.cn/20250120/375a0de3a7fc416096799714eaf...
aDyslecticCrow•1h ago
Microgravity is not the target environment for the technology , and it verifying its operation in microgravity feels like a very minor breakthrough compared to the tech itself.
So sending it to space is performance to show off and make headlines.
Its very important tech. If their claims are true its amazing... but doing it in orbit is not the amazing part.
China is doing alot of great research, and the idea that china is behind is laughable in many sectors. But sorting through the real science is so much harder in the noise of empty papers and puffy articles.
> That's quite optimistic.
Urgh. One can dream i guess