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urmomaisjabbathehutt t1_j8oehrg wrote

kind of like europe with ariane 6, traying to compete in price reductions but trailing in rehusability

tbh i'd love to see somebody one day to leapfrog up from what we have with newer technologies towards single stage planes, hypersonic engines, and maybe in the future if it pans out plasma jet engines

one can deam, can i?

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Bewaretheicespiders t1_j8plj2z wrote

>i'd love to see somebody one day to leapfrog up from what we have with newer technologies

Neutron and Stoke's upper stage both have some pretty original designs.

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The_Solar_Oracle t1_j8qhuf2 wrote

Single stage to orbit is highly unlikely to happen (or at least become common) in the foreseeable future. Even very optimistic concepts have very small payloads for the masses in question, and any weight gained during development could compromise that capacity. Moreover, there's a case to be made against SSTOs given other potential designs.

Reaction Engines Limited 2014 concept detailing the Skylon D1, for instance, has a 325,000 kilogram fully fueled SSTO delivering a 53,500 kilo vehicle (empty) into the lowest possible equatorial orbit with 15,000 kilos of worth of payload. That 53 1/2 ton vehicle is a larger penalty against the payload mass than the STS' Orbiters were, and the payload capacity itself is inferior to modern, partially reusable Falcon 9s. Yes, they're not totally reusable, but one wonders if the savings of reusing that expended mass would be worth the added developmental costs.

If the SABRE engines are not as good as thought or if new features and their extra mass must be added (as had happened in the aftermath of the Falcon 9's initial landing failures), the resulting payload mass reductions would be larger than they would be for multi-stage craft. Hypersonic engine research is also very difficult and very expensive, and that high R&D means there would have to be a significant frequency of flights and low turn around time for the vehicle to be competitive. Additionally, Skylon D1s delivering payloads to higher orbits would invariably rely on independent upper stages that would likely be disposable.

However, as far as plasma jet engines go, the largest bottleneck for them is energy storage. Amusingly, Gerard K. O'Neill's 2081: A Hopeful View of the Human Future had launch vehicles conveniently get around this issue by using Solar Power Satellites as their energy source during airbreathing mode in lieu of storing it all onboard. Not bad for a book published in 1981! While we are currently in want of SPSes, the idea has finally gotten real traction in the last decade with the entities within United States, China and Europe having committed to launching SPS testbeds into orbit in the next few years.

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urmomaisjabbathehutt t1_j8r2pt5 wrote

that is an interesting resume, thanks

the situation kind of reminds me the issues we have trying to achieve fusion energy, in both cases we know the that phisics work, we know is a desirable outcome but we need to workout the engineering problems

payload size may be an issue with early technology but if we at least manage reliable vehicules for human transportation that is one less problem and lower risk level until we can figure heavy loaders and eventually we are going to need an increased number of people working upthere becoming routine

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The_Solar_Oracle t1_j8utuaa wrote

>"the situation kind of reminds me the issues we have trying to achieve fusion energy, in both cases we know the that phisics work, we know is a desirable outcome but we need to workout the engineering problems"

Sometimes, engineering problems can themselves be insurmountable or simply not worth implementing. It's not a great feeling, but it's happened in the past and will happened again.

Nonetheless, the low payload capacities of SSTOs are a big risk because there may simply not be a worthwhile market for such small sizes. So many people focus on kilos to Low Earth Orbit while failing to take into account any other factor. It matters very little if you can get 1 kilogram to orbit for mere pennies at a time if no one wants to launch something that small, and a lot of payloads require additional space or higher orbits that any near-future SSTO would be hard pressed to accommodate.

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holyrooster_ t1_j8r5tb6 wrote

> towards single stage planes, hypersonic engines

That's never gone beat a reusable 2 stage vehicle.

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urmomaisjabbathehutt t1_j8rckmu wrote

how do we know till start developing it?

are we condemned to live with refining 1950 designs forever?, is that the best we can do?

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pufftaloon t1_j8u1cab wrote

Have you ever tried playing Kerbal space program? If you get into it you'll very rapidly understand why SSTO designs are not worth it.

Every kilogram of mass you have to lift to orbit requires multiple kilograms of fuel. And that extra fuel itself requires fuel to lift it. Staging allows you to jettison mass part way, meaning you need to carry significantly less fuel over all.

First stage reuse is a solved problem, and there's multiple very cool ideas for second stage reuse in development right now. We're so close to cracking this.

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urmomaisjabbathehutt t1_j8ujz8w wrote

you talk about the problem with extra fuel needed yet mention that there are some trying to develop a reusable second stage which incidently will require fuel

so lets watch the youtube video about why single stage rockets suck right? oh shit conbustible

meanwhile i'm talking about different technologies

hypersonic and sabre engines take advantage of the air in the atmosphere so they don't need to carry so much oxidizer with them

on a very quick search designs similar to this

https://physicsworld.com/a/air-breathing-rocket-engines-the-future-of-space-flight/

or this

[https://www.researchgate.net/publication/27524937_StarRunner_A_Single-Stage-to-Orbit_Airbreathing_Hypersonic_Propulsion_System]

still looking further ahead there are other technologies being explored and imho that can be explored further

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holyrooster_ t1_j99tm6h wrote

> how do we know till start developing it?

Because even the most optimistic assumptions about it, are already beaten by Falcon 9.

So if you can't even make it work on paper, how are you gone make it in real live?

> are we condemned to live with refining 1950 designs forever?

I mean you are stretching the definition of 'refining'. Starship is a just as much an upgrade over 1950 rockets then Skylon.

In fact, Skylon is actually how many people in the 1950 imagine the future, while Starship is the reality checked version of what will actually work.

> is that the best we can do?

If you want to really go invest in the future design, how about an air breathing nuclear turbofan. But I think that might cause some opposition.

You also need to consider that money is limited. Every $ going into air breathing engine isn't going into something that has potentially much greater effect. The investment done into Sabre engine would have yield far better results if it has been invested in reusable FFSC. Or something like a closed cycle expander areospike. Or many other things that that have far greater potential then Sabre.

The reality is that Sabre and Skylon are a product of a British team, a team of people that basically spend 20 years designing a bunch of paper rocket, having little experience what so with actual rocket flight operation and they came out with a concept they was so over-the-top that they thought they could get some serious research money finally.

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LcuBeatsWorking t1_j8qvv7g wrote

>with newer technologies towards single stage planes

Single stage to orbit from earth is a waste, whatever great technology you use. If two stage full reuse works out it will always be more efficient.

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urmomaisjabbathehutt t1_j8r0kyt wrote

pity people like reaction engines doesnt get more money

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LcuBeatsWorking t1_j8r0w9h wrote

Why should they? They haven't presented a working prototype of their engines in 30 years, and there are a lot of questions about that design.

And even what they propose to do with it (Skylon) isn't really a good idea.

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holyrooster_ t1_j8r8ekv wrote

Disagree. Money can be invested much better. Their technology isn't that great and their vehicle is mostly fantasy. It would take absurd amount of money and likely they couldn't make it work at all.

For that same price you could build way more useful things for space flight.

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urmomaisjabbathehutt t1_j8rc8g5 wrote

we could take the same view with other technologies like fusion in the enegy industry or advanced designg nuclear rocket engines and still get us nowhere but perfecting 1950s technologies

imho those people had been testing their technology for years but the company size and available cash is nowhere to be able to proceed with the desirable development speed

further ahead there are people working on other types of hypersonic engines

and in the future even plasma jet enginess (fairly early stage and with many issues to solve such as the amount of energy...) fairly stage but imho worth exploring since a breakthrough on such could change not only space industry but the entire aerospace industry

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holyrooster_ t1_j99ucyo wrote

> we could take the same view with other technologies like

Yes. We should look at fundamental physics when making investments.

Fusion is mostly dumb for almost all application. Most nuclear rocket engine designs are pointless and not really worth it as well.

> imho those people had been testing their technology for years but the company size and available cash is nowhere to be able to proceed with the desirable development speed

If you are proposing a design with limited upside but at least 100 the cost of a conventional design then of course you can't do that.

The reality is the Skylon project was barley more then 1950 sci-fi, to go 'full speed on development' would have cost most of the European space budget. And all for a concept that serious technical issues, a team with insufficient knowledge and experience and limited upside.

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