Why Don't They Launch Rockets From Mountains Or The Equator?

Why aren’t we taking full advantage of the planet we’re living on? If we launched rockets from mountains, they'd be closer to space where the air is thinner so we could use more vacuum optimized engines.
Or why don't we launch rockets from the equator? The Earth is moving quite quickly at the equator which gives a substantial boost in the initial velocity of the rocket. I mean it’s free energy right? How much of a difference does launching rockets from different locations actually have?
Today we’re going to dive into the physics of launching rockets from different spots on the earth. We’ll go over the pros and the cons of launching from mountains or closer to the equator in great depth and see if we can figure out why exactly we just don’t see rockets launching from these locations all that often if at all.
Prerequisite "Orbit VS Suborbit" - • The MASSIVE difference...
00:00 - Intro
02:45 - Launching from a mountain
12:45 - Launching from the equator
20:10 - Summary
Article Version - everydayastronaut.com/why-don...
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[@osprey413]

Something else about launching from a mountain would be the weather. Not just snow and ice, but wind over the top of a mountain can cause some pretty extreme turbulence in the air, which could make it more difficult to control a rocket launching from a mountain.

[@slaphappyduplenty2436]

It’s plenty windy a few thousand feet above Florida too.

[@docferringer]

@@slaphappyduplenty2436 It's the wind at the level of the launchpad that is the issue. Once the rocket gantry is retracted the rocket has to stand on its own, so Cape Canaveral will call off launches even for strong rainstorms.

[@MarkoVukovic0]

@@raya.p.l5919 what, a 2000 year old zombie? Sit down.

[@raya.p.l5919]

@@MarkoVukovic0 for your reply u will receive Jesus healing energy all old aches and pains will be washed away. Takes 30 minutes best to relax and shut yr eyes. Also all who read will receive level 1 portion of youth longevity digestion an self beauty Jesus energy wash. Negative energy will creep out yr feet tell it's time. Or I'm lying an yr closest friends won't experience it to

[@noahmaness4669]

@@raya.p.l5919why here tho?

[@RudCh01]

One note, French Guiana isn't a territory of France, it's an overseas region and department, which makes it analogous to a US state like Alaska or Hawaii rather than a territory like Puerto Rico or Guam. Fun fact: France's longest border with another country is shared with Brazil!

[@paulstewart6293]

Americans don't bother to think about Ariane, a very successful rocket, which launched James Webb because no one else had a big enough one. Apparently the launching was so good that the téléscope gained a few years of autonomy supplementary.

[@SuperCatacata]

​@@paulstewart6293Most of the world doesn't think about it if it involves France. They will be sure to brag about it to your face instead.

[@androcreer783]

There is also a port space in Brazil, it is one of the closest to the equator

[@wallacemjr]

@@androcreer783 I think it is the closest to the equator at 2° 22′ 39.52″ S. Alcântara Space Center (CEA)

[@androcreer783]

@@wallacemjr yeah

[@7secularsermons]

Mt Kilimanjaro is almost on the Equator and nearly 6000m (nearly 20000 feet) high. If in some distant future, Tanzania could build the infrastructure to transport or build rockets there, and Kenya could clear out the approximately 300 km to the Indian Ocean, they might be able collect some good rent from launch providers.

[@pastorjerrykliner3162]

So long as there isn't eruption...yeah, it could work...

[@Kazyumi]

Shame they don't have any of the logistics and industry nearby.

[@borghorsa1902]

@@Kazyumi They was kings!

[@helgekumpfert4011]

Ok. But its pretty hard to work at that hight (for a bit elder people almost impossible). Beyond, the rockets would have to fly over populated area.

[@alainportant6412]

@@borghorsa1902 They just don't have the genetics to launch a space program.

[@debott4538]

Fun fact: When launching very close (

[@simongeard4824]

Yes, I'm surprised that wasn't stated so clearly. Yes, the equatorial rotation advantage is certainly useful... but the benefit of not needing to do a dogleg turn is also a huge factor, and I might have expected Tim to break down those two factors a bit more.

[@debott4538]

Same here. That's the reason for my comment. He likely knows that, too, since it is clearly stated in the video. But no matter how awesome the video, it has to end somewhere, right? ^.^

[@DK.dk11]

100% this. Love this comment after sifting through pages of maglev BS 😂

[@debott4538]

@@DK.dk11 Hey. thanks for the lovely reply. :) Edit: oh and also, Starship! Woop!

[@steverobbins4872]

This brings back memories for me. When I was an engineering student back in the '80s I thought of launching from a mountain somewhere in Central America using a maglev (similar to hyperloop) that started from a floating platform in the Pacific. I also thought a big laser pulse fried along the trajectory just a few milliseconds before the vehicle emerged from the tube would lessen the shock of suddenly hitting atmosphere at high velocity. But I didn't have the math back then (or the patience) to work it out, so I'm really looking forward to part 2 of this video.

[@mgg4338]

Best idea so far! 👏 Chimborazo could become a space-hub. Rockets from the factory could just land there nearby (~falcon 9) be refueled, loaded inside the hyperloop cannon and launched at a fraction of current cost

[@Horsegirl852]

I have a similar Idea of using Mnt Kenya on the equator near the east side of Africa. Use a maglev sled to get to high subsonic speed (breaking the sound barrier at ground level not good) to replace the heavy first stage booster.

[@KatanaFPV]

The initial booster does assist in achieving some level of desired trajectory and stability but sounds possible with some tweaks! Love these ideas.

[@MyAdventurr]

(Other than politics/regulations) I was wondering why we don’t use a boring tunnel machine to drill down from the summit of an equator mountain. Then use the tube(s) to build maglev/hyperloop/railgun tech for our payload/rockets. Way I imagine it, like a sniper rifle but the barrel is built into the mountain and the bullet is our rockets. That way we can deliver our materials to the base of the mountain and launch/lift them to the summit and beyond.

[@mgg4338]

@MyAdventurr in case of starship we can simply land our rocket at the base of the mountain, refuel, load it inside the barrel and then launch from there. It will reach orbit with much more fuel and could be used to reach Mars in acceptable without orbital refueling, which is the current plan and, quite frankly, it looks like a compound clusterfuck

[@toonarmycaptain]

I always had the hunch that launching from a mountain would have some benefits - less altitude to attain, thinner atmosphere, but that the majority of the effort isn't so much getting to 4-10km, but reaching the velocities attained by that altitude.

[@jacobp8294]

Exactly, in the grand scheme of things those few km gained may end up being less than the fuel expenses of delivering the materials.

[@Endeva09]

I like to think of myself as a reasonably intelligent guy but I don't understand your comment, what do you mean by "reaching the velocities attained by that altitude" ? If you could explain further please I would most appreciate it.

[@MrMeow-iq7kq]

I imagine staff actually adds up to more total cost than the rocket and fuel. Everyone would have to live away from home while working,... feeding and lodgings suddenly become a bigger concern. All sorts of issues(Sorry if video mentions this,... im only like 1 minute in)

[@MrMeow-iq7kq]

@@Endeva09 acceleration. Typically at ground level you start at zero speed. At 4km elevation your rocket is usually going pretty fast. So if you start your launch at a 4km mountain, you are starting at zero speed. The benefit Toonarmy kinda misses is that all that gaining speed no longer has to fight against nearly as much gravity and atmosphere- which gravity and atmosphere being the biggest contributors to fuel consumption. So he is kinda wrong that its the velocity thats at fault because you are spending fuel to gain that velocity either way. Its again, the cost of gaining that speed and maintaining it where the real struggle is and why theres a benefit to starting higher up. But those benefits are also likely microscopic compared to the costs it would take to logistically arrange all this and make it feasible. I agree that 4KM might not be significant enough... But the video downplays these gains by going as far as saying "even if we started in space, we'd still need to gain the velocity so there is no real benefit" But that ones a bit extreme, since you'd need like half the deltaV at that point, and because you'd need less fuel you would have a smaller craft. The benefit of starting there is so huge, I cannot even begin to describe how much he downplayed it.

[@Endeva09]

@@MrMeow-iq7kq conservation of momentum though?

[@DownhillAllTheWay]

At 6:55 - That animation of the potential orbit varying with speed of the spacecraft - is brilliant. It's an intuitive, visual representation of something that is actually quite difficult to explain to people.

[@deebo3864]

Thats been happening since the dawn of computers and rockets. Its nothing new. Even games have that animation

[@AlexBrown320]

Fantastic video as always Tim. Further on the subject of launch sites, how about a dedicated video on rocket launch facilities; a brief history of the main worldwide launch sites with location illustration, what types of rockets launch from them and the orbits they use. Maybe with an accompanying video about what it takes to launch a rocket (ground service equipment, tracking stations, roles in the control room etc).

[@PJ818]

I've always thought Mt Chimborazo in Ecuador would be a great launch site. Sure, it's more of a West Coast launch site; but it's less than 2° of latitude from the equator, and while it's shorter than Mt Everest, because of the Earth's equatorial bulge, its summit is the farthest point from the center of the Earth. Cultural sensitivities might be an issue, because I think indigenous cultures thereabouts tend to hold mountain peaks as sacred; but it's still a fun idea to play with. (Typing this prior to watching the video, I just have always loved this idea.)

[@PJ818]

...I also played around with the (very hypothetical) idea of building a railway from a sea port to the top of Mt Chimborazo.

[@mgg4338]

Or a falcon 9 can land on top, refuel and re-launch from there. I'd definitely set a refueling station on Chimborazo

[@Lasseyboy]

Check Mount Kenya’s location 🎉

[@PJ818]

@@Lasseyboy Better than Mt Chimborazo from an eastward position, but still not right on the coast. Still some land flyover.

[@MatthewElvey]

@@mgg4338 I love that idea - (for Starship too!). A lot of fuel would burn off just because of heat absorption, between the landing and the re-launch. And slowing down for a landing with almost full tanks would take way more energy than slowing down for a landing with nearly empty tanks does. I wonder how significant these problems would be. Anyway, I think SpinLaunch should be on Mt Chimborazo. And they're looking for a build site!

[@The-Drone-Hobbyist]

As someone who lived where space x first started testing the falcon 1, years ago(Kwajalein Atoll) it seems like a great place as it’s closer to the equator but on the other hand it’s thousands of miles from mainland so probably why it isn’t an option. Thank you for this video Tim and keep up the great work

[@mriguy3202]

Space-X had a lot of practical trouble from that launch site; Ashlee Vance's book, When the Heavens Went on Sale would be enjoyed by many of the fans of this channel. It was remote, so there were costly delays all the time. It was bereft of human support for the staff--not so bad for a handful of young men who might be happy in the short term sleeping in trailers, working 80 hours every week, and drinking when not at work, but not practical when scaled up and made permanent. The tropical climate created a lot of corrosion. It was very costly to ship emergency parts and personnel down and back. There was a case to be made for doing that when the proof of concept was done, but having a location where the staff can sleep in their own beds at night is a more sustainable plan. The human salaries are a very costly and critical part of the process. Now Space-X is at large scale. Not everyone wants to live in California or Florida, but an awful lot of engineers find that acceptable.

[@nathanlee6654]

I've been a huge fan of yours for three years! I absolutely love how you present concepts with great graphics and very well-done research. The icing on the cake of it all is that you write fantastic music that goes along with it. No other artist that I've found has put the glory or majesty of spaceflight into music, except for maybe Test Shot Starfish. What you do is amazing!

[@antonyinterlandi6657]

I really enjoy and appreciate the effort, quality, and information that you put into your presentations. Your explanations and attention to details make for very informative and easy to understand videos. Well Done. Always look forward to the next video. On a slight side note, how is your training going for your trip around the Moon? Would love to hear how you are progressing.

[@xpelestra]

I remember watching some documentary when I was a kid and I vaguely recall this part about using electricity to launch payload to space. They demonstrated it by hooking up 2 aluminum plates to car battery or something (probably some super capacitors) and they launched one on top couple feet in the air. There was a computer animation of launch facility which was 2.5km vertical tunnel to the top of the high mountain, with walls lined up with electrodes that would accelerate ship made out of metal. But the problem was it would require insane amount of energy and launch would sound like thousand thunders. I always thought if was cool concept but probably not feasible same way as hyperloop. But using what is basically a railgun to launch small payload from the surface of the moon for example could be interesting implementation.

[@kennethhicks2113]

Not just a space transportation problem, we discover/engineer new things and then decide to manufacture them in high risk/costly locations. Great vidy as always, have a great day : )

[@justalonesoul5825]

Quality content as always! Glad I had most elements right before they were nicely exposed. Looking forward to the next part!

[@imjashingyou3461]

As far as the US I was always surprised that Puerto Rico or the US Virgin Islands were never used. There is plenty of infrastructure there, its US soil, is much further south then FL or TX, and its close to the continental US, with constant sea trade going back and forth from Houston, and Jacksonville. It also had a massive US Navy base on the East coast that is now BRAC'd.

[@JimAllen-Persona]

No congress people come from Puerto Rico, no pork to distribute. You think Houston was chosen for its location or to placate LBJ?

[@High_Alpha]

@@JimAllen-Personasadly true, if PR was a state then it would already be the prime launch facility.

[@chicken29843]

​@@High_Alphawhat is Puerto Rico's position on that I don't know what Puerto Ricans actually think about having statehood. It does seem fucked up that they seemingly have less rights than other citizens.

[@JuanGonzalez-nn6dw]

@@chicken29843We do have less rights even though we are US citizens. In terms about the statehood, PR’s government is rotten of corruption creating crisis and impeding the growth of our nation. My personal stance is independence but either way statehood or independence will never come before fixing our internal problems. If we were to become a state, I’ve also always thought about the potential of a launch facility in PR, but it wouldn’t come without its own issues.

[@Icspiders247]

@imjashingyou3461 If you look at a map, the answer should be obvious.

[@P455w0rds]

Launching from Mount Everest will be a wonder of engineering😂❤❤

[@AlanCoffey]

Send Proofrock up there.

[@vighneshpokale5287]

Nahhh.......Launching from Olympus Mons will be the greatest feat of humans

[@foxmccloud7055]

Assuming that you can find a way to protect the public from errant rockets.

[@zsigmondfeher4624]

How will they get it there😂

[@setituptoblowitup]

Not if you're a jeep can't do it first

[@olafmesschendorp147]

I litteraly subscribed like 10 minutes ago watching your SLS vs Starship video (I love both) and several minutes later you post a brand new video :D I love your video's!

[@jaredkennedy6576]

I'm eagerly awaiting part 2, as my thought process is basically all of the above. An electrically accelerated inclined tunnel up a mountain, with first stage being a scramjet or similar air breathing engine, which upon staging will pop out wings to fly to an airport for recovery. Then the second stage will light in very low pressure. A lot of the initial acceleration will be from external fuel, so kind of short circuits the rocket equation pit.

[@yannickhein9788]

Yes, that, or the other smaller brother of that option: an electrical or mechanical acceleration from a 500m deep tunnel up to a 500m high launch tower (tunnel and tower sizes made up, assuming you have no geographic possibilities or in case it is preferable to launch vertically). This gives you a basically free velocity and (small) height kick-start. So @EverydayAstronaut "why don't they just..."?

[@QuantumHistorian]

The answer to all of this is the same to those he gave to both questions tackled in this video: huge infrastructure and logical costs to slightly improve performance are not worth it. If the trade-off was balanced the other way, we'd already be doing it. Sure, you could make some kind of catapult that shoots out your rocket at a few machs in order to reduce how much delta v it needs. But then not only do you need that very expensive infrastructure, you also need to make your rocket physically stronger to resist both the catapult's acceleration, and the impact of hitting the atmosphere very fast. You just don't gain enough to make it all worthwhile - not on Earth anyway. Spinlaunch disagrees, but they're very much a minority opinion. As for air-breathing engines, nobody's managed to make one that produces enough thrust to be useful on a rocket (planes, after all, are lighter and rarely fly vertically). You'd need a huge number of them to be useful, which would be hugely expensive and add more weight. All for performance gains that only applies to, at best, the first minute of flight before the atmosphere gets too thin for there to be any air to breath. Just so much easier to strap on a few SRBs that achieve the same thing. This could change with dual air breathing/rocket engines like the RAPIER, but that's just on paper at the moment. Incidentally, jet engines aren't vastly more efficient than rocket engines because they burn the oxygen in the air rather than in tanks, but because they use the air as _reaction mass_ . The wiki article on specific impulse explains this pretty well.

[@jaredkennedy6576]

@@QuantumHistorian I understand that the cost to get this system spun up is immensely higher than the cost to launch a rocket, but if we're going to be launching on a pace like SpaceX is working towards, that initial cost can be amortized over a huge number of launches. It will still have operational and maintenance costs, but those would be far less than the cost of fuel for a conventional launch. There is still infrastructure cost with conventional launches as well. Done right, these could be solar powered with banks of batteries or supercapacitors to store power for each segment until needed. I am familiar with the difference in efficiency between rockets and jets, I'm not thinking to use a turbofan or something, but a high performance super to hypersonic capable air breathing jet. This is a tech we've been on the edge of for a while now, that once it is sufficiently developed will be a viable alternative to a pure rocket within the atmosphere

[@QuantumHistorian]

@@jaredkennedy6576 Firstly, there's no reason to think that SpaceX's planned cadence is at all realistic. At the moment, the demand for launches that they're supplying is dominated by Starlink. As that's also an Elon thing, it smells like a little like a ponzi scheme. But even beyond that, eventually the constellation will be built, and the replacement rate will be much lower than the current launch rate. Or, to put it another way, there's not enough space in (desirable) Earth orbits for anything like the massed launches that SpaceX is dreaming. Postulating a huge demand for launches to the Moon or Mars to make up for it is fantasy. Fantasies sometimes comes true, but it's a weak basis for a sensible argument. Not to mention that launching at that cadence would have serious environmental costs. Secondly, the point I was trying to make is that it's not just the setup costs but also the running costs that are higher with more complex systems, even if only for logistical / operational reasons. The more sophisticated you make the system in order to have the greatest efficiency gain for the "traditional" part of the rocket, the more these costs inevitably also rise. There might be a point where it's worth it, but it would - at best - be a huge gamble that requires enormous R&D investment for a very modest gain. If your plan is to reduce fuel costs then that's already a non-starter, fuel cost is negligible in rockets. The Space Shuttle might be the best example of theory vs practice in space tech, despite being theoretically capable of cheaper run costs, it ended up being one of the most expensive ways to put things in orbit for years. Compare that to the reusable Falcon 9, which essentially uses already well developed rocket technology in a far better way. That's much easier to develop or even bootstrap than inventing entire new systems from scratch. Do you mean something like ramjets or scramjets? Those aren't much more efficient than rocket engines (far far less so than turbofans) so the potential for gain is limited. They also don't work at low speeds, so you'd need another type of conventional engines to get you off the ground and going at a few machs before they can really kick in. This means that they would have to be used in tandem with something else, and leaves a very narrow window during a launch where ram/scram jets would actually be useful. The way they might actually work is to essentially launch a rocket from a plane - pegasus or virgin galactic style - and have the mother plane have such jets. Such air-launches do work but don't have the greatest track record of economic viability, not to mention that the mother planes are typically huge and making them go hypersonic without breaking apart might be a lot to ask. On top of that, ram/scram jets are one of those technologies that has been "almost ready" for decades, so I'm not holding my breath.

[@jaredkennedy6576]

@@QuantumHistorian I think that having the capacity for inexpensive launches will create the market. Twenty years ago, ride shares and independent R&D satellites were somewhere between rare and non-existent. Today, it's a decent segment of the market. In my original post, the first stage is an electrically accelerated inclined tunnel. So Stage 1 is a sled that interfaces with this launching tunnel, gets run up a few kilometers while being accelerated to near supersonic speeds, then upon exiting the tunnel will ignite an air breathing engine that carries the whole thing to 80k+ feet. The tunnel would need to be evacuated so that there is not a big slug of air needing to be pushed out, and the pressure at the exit point is roughly equal to prevent slamming into a wall of air as well. So now you have a platform that is on the edge of mach 1, and has gotten there without burning a drop of onboard fuel. It's entirely possible to use an engine like those on the SR71, or some other airflow tricks to get decent supersonic performance out of a turbojet, but at the very high altitude and high speed end of things a scramjet would be better. So now we're at 80-100000 feet, mach 3-5+, the stages separate, and the upper stage rocket ignites carrying the payload into orbit. The scramjet stage pops out some wings and glides back down to a runway landing.

[@SirThreepio]

Tim Dodd's show is educational and inspiring as usual. Every high-school would battle to have him as a teacher.

[@notsomadscientist9602]

I have missed Tim Dodd videos!!!! Great content as always brother!

[@MrNick99]

this guy makes incredible content. Bravo!!

[@thomaskendall452]

Exceptional video, Tim. Simply outstanding!

[@lukyluke993]

Love to see part 2 because I did research on slingshot designs for rockets back in school. That was real fun 🚀

[@danwylie-sears1134]

I like the idea of an air-breathing first stage, that could launch from the most convenient place for a runway and then fly at jetliner costs to the optimum latitude for each payload, then start paying the rocket equation above most of the atmospheric drag and above the possibility of any interference from the weather. I know it doesn't work out, for a bunch of reasons that will be spelled out in the next episode, but it's a neat idea.

[@spacecadet35]

Spaceship 2 does this.

[@oasntet]

It sort-of can work, but not for rockets. The SABER engine project, if it manages to overcome the engineering challenges, could make a fully-reusable SSTO spaceplane viable. It might even be able to out-do Starship for launch price, assuming SpaceX manages to overcome _those_ engineering challenges...

[@bobdalton2062]

Great job explaining it all and the importance of trade-offs in engineering and real life. Always appreciate your videos Tim!

[@petebyrdie4799]

Fascinating! This has answered so much that I've been thinking about for years. I'm definitely subscribing and looking back at previous videos.

[@StarkTrist]

Woot! Thanks for making this video! It's nice to know why they do/don't fly rockets from specific parts of the planet.

[@Meatloaf_TV]

It's always a good day when Tim dodd posts a new video

[@AverageDiscordMod]

Why are you using his full name lmao, are you his mother??

[@Meatloaf_TV]

@@AverageDiscordMod shorter than every day astronaut also why do u care

[@AverageDiscordMod]

@@Meatloaf_TV I just find it weird..

[@Meatloaf_TV]

@@AverageDiscordMod fair

[@raya.p.l5919]

❤ Jesus power. ❤ warning it is intense ❤..

[@stevesawyer7964]

Great presentation! I also remember Pegasus launches by Orbital ATK (now Orbital Sciences Corporation). This combined both optimizations from a jet.

[@patreekotime4578]

Something he hinted at but didn't directly say is that when it comes to rocket designs with multiple engines, a higher altitude launch site is actually a bad thing. Sea level rockets can clump more engines together closer. So that high altitude launches would typically be payload constrained to medium-sized rockets with only a single engine bell.

[@VestedUTuber]

In regards to launching from the equator, it's actually a viable option _if_ you already have a facility there. In Kerbal Space Program, your primary launch site, Kerbal Space Center, is located on a short, wide peninsula on the equator. As for launching off of a mountain, again, if you already have the facility there, it's a great idea. But getting things up there can be a logistics nightmare. I've had a similar idea to try and bypass the lower atmosphere in the form of a lighter-than-air launch platform. It's one of those "it works in Kerbal Space Program" things, though - in other words, it works in theory but actually doing it is another story.

[@stevecoates3799]

Another outstandingly informative production from the Everyday Astronaut team. Congratulations

[@luismelchertfaberschmutzle578]

Helo Tim! Very goog job, as usual. There are 2 lauch sites in Brazil, the Alcantara lounch base at only 2,18 degrees south and Barreira do Inferno at 5,55 degrees south. Ok, I know, there may be not so good political alignments there. There is also Hawai, that is 21 degrees north and has the mount Mauna Kea, with the high of 4205m, and is under USA administration, why not?

[@brianw612]

Everywhere is under US regulations. SX requires an FAA license for launch or re entry anywhere on earth.

[@istochnikov45257]

As far as I remember, Alcântara was always begging for a launch vehicle. The last one was a Kerolox derivate of the R-16 Scarp Soviet missiles: The Tsyklon 4

[@raya.p.l5919]

❤ Jesus power. ❤ warning it is intense ❤..

[@luismelchertfaberschmutzle578]

The problem of lounching rokets from Hawaian mountains, is that there are telescopes, very large telescopes , and the vibration would destroi tham.

[@gfopt]

@@luismelchertfaberschmutzle578 Mauna Loa isn’t covered in telescopes.

[@mikeconnery4652]

Your channel always has great content. Thx

[@koosdreck]

Might go in a good direction with these vids. Inspire people and ask the right questions. Will make a difference, will inspire new ideas that might just end up changing the world. Well done.

[@FrankPace54]

Thanks Tim for another well researched video. Here's one for you. I would love to see how space X refurbishes the falcon 9 boosters, fairings, and attaches a new 2nd stage assembly right down to launch ready. Talk to Elon and see if he'll give you that tour. Could be a cool vid!

[@AlienScientist]

Now that he did this video, he should do one on rockets launched from balloons!

[@mikeconnery4652]

Not launched from balloon, launched in a balloon.

[@AlienScientist]

@@mikeconnery4652 Actually usually suspended beneath the ballon and lauched at an angle...

[@mikeconnery4652]

​@@AlienScientistNo. Inside. Start 1 rocket engine. Looks like a mushroom! (?) Ship lander with no loss of water.

[@JohnWilliamNowak]

One thing you only mentioned briefly was a equatorial launch site providing the ability to launch into any inclination. This is a real world concern where the Russians cannot at present launch a Soyuz from Baikonur and reach the Chinese space station. There's a Japanese IP called Rocket Girls which uses a launch site in the Solomon Islands, which is equatorial and has the advantage of islands downrange where a reusable booster might land. The fictional company which did all this was naturally Japanese, so reasonably close to the factories.

[@QuantumHistorian]

Yeah, he kind of missed that point: it's not an addendum, but a key factor. A lot of the advantage of launching from the equator for geostationary orbit isn't so much the free velocity, but from not having to do a dog leg manoeuvre or an orbital plane change. For example, going from a 26 degree orbit in LEO to an equatorial one costs an eye watering 3.5km/s of delta-v! That's half of orbital velocity! You can do better by changing planes later, the same 26 degree change at the apogee of a geosynchronous transfer orbit can cost as little as 1km/s of delta v if the geometry is just right so the apogee is directly above the equator. That's much bigger than the extra 0.05km/s you get from the earth's rotation by moving from 26 degrees latitude to the equator. There's a reason why the main commercial use of the Ariane rockets and their amazing French Guyanan launch centre is geostationary.

[@austinmackell9286]

The country of Ecuador has entered the chat. High altitude, on the equator. Pretty good roads.

[@JohnWilliamNowak]

@@austinmackell9286 It's on the west coast, so any failures would crash in Brazil. Otherwise, yes. The documents for Project Horizon, written before the selection of Florida, proposed Brazil and Christmas Island as the best contenders.

[@charlesyoung7436]

IMO, the best unused potential equatorial launch site is near Kismayo in Somalia on the Indian Ocean east coast of Africa. Of course, there are problems with the politics in the region. Indonesia has several potential launch sites, as well.

[@benjaminfranklinkivettiv9433]

I learn more from you than all the other space platforms put together. You just make everything understandable for my little brain. 😂thanks Tim. Really enjoy your vids

[@goofyiest]

wow. I really had some preconceived ideas about this and you totally convinced me. Great video.

[@troym79]

Awesome video Tim! You're doing a great job speaking to us more naturally and not straight reading from a script. I sure you have at least a bit of a script or outline of topics to hit, but yah love the authentic-ness to it. So cool that my wife and I met you at SPI just before the IFT-1 launch! You're much taller than I thought!

[@terrysullivan1992]

Part of that is he really knows his stuff. Great example was his interview / conversation with Elon while touring Starbase.

[@Moredread25]

The sea launch thing is interesting. I didn't know people actually had done it. To me though it seems quite likely that it will increase costs and cause complications that make it much inferior to land launch at a regular facility that is the best option in the country you are operating in.

[@TheEvilmooseofdoom]

The bigger the rocket the more complex sea launch becomes if from something that is floating.

[@mateuszzimon8216]

IRC Sea Launch (company) used Zenith rockets launched from ex oil platform. They "suspended" flights in 2014, now they are part of S7 holding (same holding have a lot of problems with uninsured leased from West planes) It's doable, yes cost more but u can get up to 20% heavier payload or lifespan.

[@athul_here_]

Informative as always ❤

[@user-ng2nt2tx4p]

I'm familiar with FAA" Waiver's" on airspace as I used to build and fly some amateur High Power Rockets. At the second launch I attended, in addition to the 5000ft Waiver, we had a 1 hour call in window for higher altitude. Our sky's were clear when it was called in except for a passenger jet off in the distance heading our way. Within 3 minutes of it being granted that jet made a 90 degree turn to its right to avoid our airspace. The FAA takes airspace seriously! Thanks for the Video!

[@triforcefx]

Rocket launches off of Pikes Peak might not be practical, but they would be absolutely stunning and majestic to witness (so long as you don’t have rocket parts falling down on the city)

[@tskyrhonda]

Great! I’ve also always wondered if SHARP tubes or rail gun launch assist incorporated into some stage-0 launch pads at some point? Maybe next episode 😊 Tradeoffs.. 👍

[@stephenevans-2paradox767]

An electric rail launching track (super high speed rollercoaster style) up or in the side of a mountain near the equator near the ocean might be a really nice boost, especially if the rockets were made cheaper and smaller and there were more of them launched each year. Finding a way to incorporate a low cost catapult system with a release point that is near the speed of a cracking whip, would also be neat. Of course, finding the best release point so as not to destroy the rocket and payload 🙂

[@Redact63Lluks]

For things like launching fuel or some kind of processable solid fuel payload, food, and other stable things like construction materials, I think it's a great idea. But you really can't do that with people unless we stuck them in some kind of protective suspension that would be punitive in execution.

[@goadamson]

Great video! Can’t wait until #2 (and likely beyond!)

[@nicholasperry2380]

Beautifully explained Sir. Adding the hard data is a great move allowing us to quantify the difference. Thank you for another superb presentation.

[@garymartin9777]

When you think about it Space-X chose a pretty prime spot for their launch site in Texas. They have the Gulf to catch falling debris, it's pretty far south, the region is not heavily populated and it's flat so transportation for fuel and supplies is a breeze and employees can live relatively close to the site so getting to and from work doesn't cost much.

[@bridgecross]

So *IF* there were a mountain, on an eastern coast, near the equator, with a mild climate, good transportation infrastructure to the top, close to the rocket assembly plant...

[@target844]

It has to be in a country of a friendly nation that is stable enough to spend the money to build the launch facility and continue to use it. On the equator, you have Brazil, Somalia, and Indonesia if we just look at the eastern cost required, that is not a list of very stable countries. There are a few more if close is good enough. So the number of good options is very few for large powers that do launch rockets. The only really logical is the one that is used in French Guiana. No country has built an expensive launch facility in another country. UK might the the exception, Black Arrow did launch from Australia in its only successful launch to orbit. That is the type of national relationship you need for launching your rockets abroad. You do not want a political change in a foreign country cutting off your access to the launch facility or just demanding more money for all of you to keep using it. France did do their first orbital launch from Algeria in 1965 but the facility was built before Algeria became independent so built in France. It is after that they moved it to France Guiana was and still is a part of France. It is not a colony but an overseas department, an integrated part of France just like any department in Europe. Russia is replacing Baikonur in Kazakhstan, with Vostochny in far eastern Russia. Kazakhstan was a part of the Soviet Union with Russia, so foreign launches but built in the same country as France. Brazil does have a spaceport 2 degrees south of the equator, the equator is at the mouth of the Amazon River. I would guess it is as close as possible with good conditions. Their rocket program was called in 2016 after two failed launches and a pad explosion in 2003 that killed 21 people. We might see private companies use it or even nations, Russian Proton is not allowed in Guiana anymore. So it is the in the video unstated part of in your own country part that sets additional contains in where rockets are launched.

[@raya.p.l5919]

❤ Jesus power. ❤ warning it is intense ❤..

[@gfopt]

@@target844 In a friendly country- There’s a new launch agreement between US and Australia and the northern peninsula in Australia is much closer to the equator than US launch sites. It’s quite remote there however, so it remains to be seen if the logistics of a new launch site work out. One thing SpaceX will need down the road a few years when they want to launch thousands of tankers each year is on-site fuel production. That will need lots of power. Perhaps Australia’s ample empty, sunny land is a crucial piece of the puzzle.

[@EveryoneWhoUsesThisTV]

@@gfopt Hotham peninsula north of Darwin isn't remote, a bit close to civilisation if anything. But a pretty good launch site. :) 13-14 degrees south is better than 23 degrees north! Melville island is closer to 12 degrees.... Australia has some options for launches.

[@Oldtanktapper]

⁠@@EveryoneWhoUsesThisTVHold on, you’re calling Darwin civilised?

[@thescrapalaxy9214]

Awsome video! Do you ever plan to make a video about Esrange or svalbard rocket range, wich is at 67° N and 79° N respectively? It is could be quite interessting how they manage cold and such. Also Esrange has the potential to be Europes first orbital launch pad (in Europe)

[@Wowom]

Great video, hope to see many more like this :)

[@jeffskio]

I live in Colorado springs and I would completely be up for seeing SpaceX do this and land east of Colorado springs

[@EarlHare]

Somehow I don't think your neighbours would appreciate that bud. Besides, you have Stargate Command, that's more than enough.

[@just_archan]

I wonder if Falcon would go through Stargate🤔

[@ericeastham1256]

@@just_archan It would be able to fit, a Stargate's interior diameter is about 5 meters. The rocket however wouldn't be able to get into the Embarkation Room as it is too long, the Stargate would have to be in a bigger room, outside, or rotated by 90 degrees so that the rocket could be lowered into the gate.

[@taddinraleigh]

I like Heinlein's maglev/re-usable rocket sled booster that ran up a ramp on the side of Pikes Peak so the first stage was completely re-usable and potentially electric. Since SpaceX has managed the re-usability aspect, the only potential offset for the cost of ramp construction and operation would be the savings in liquid fuel, size of booster, and etc. It'd be quite an engineering challenge to make a robust straight smooth ramp in a mountain range. Billions and billions of startup costs. I doubt it would make sense now. There have been science fiction stories about launching ramps. It was a staple of space opera in the 50s and 60s. When Worlds Collide, Fireball XL5 etc... I recall hearing about some effort to make a launch tube, like a battleship gun barrel, to do first stage to orbit for an extremely robust cube-sat.

[@RobertMcCall-is5cl]

@@taddinraleigh Just wanted to give a shout out to a fellow "...Harsh Mistress" fan. I've read every Heinlein I could get my hands on, even the "young adults" series. I think that someday when we have a permanent base on Luna, the mag launch concept may actually be viable there. Let's just hope they don't decide to "throw rocks"...

[@ultramarinus2478]

Regarding the equator sea launch idea - can imagine spaceX starship(s) being launched from there. The logistic problems would be easier, because if the launchpad is big enough, it could create oxygen an hydrogen (as fuel and oxidizer from the sea water) could have stabilized 3D printer for creating spareparts and could house extra personel on a cruise ship stationed close to the launch pad.

[@Patrickonzales]

Nice Video😎 I would consider digging a vertical tunnel down a mountain, so you can easy access the start position trough tunnels. And you could build in some magnetic boost for the length of the tunnel. But it‘s probably gonna be a bit expensive to build🤑

[@lostincyberspaceIII]

Theoretically a launch pad in Quito Ecuador would be good since it is fairly high and is basically on the equator. The furthest point from the center of the earth MT Chimborazo is only about 100 miles south and there might be a good place in there. But a lot of the other issues with transportation and safety are there still.

[@douginorlando6260]

The theoretical best launch is from a mountain near the equator with a launch track up the side of the mountain. The whole rocket on the launch track could be accelerated on a reusable rocket sled to 1000 Km/hr before using any of its own propellent. This gives the launch the huge benefit of starting the lift-off at a high elevation with 1000 Km/hr in the ideal direction (45 degrees up) plus the 1000 mph earth rotational velocity.

[@douginorlando6260]

And to be miserly about it, if you launch from a 2 mile high mountain on the equator, then the earth rotational velocity is increased by 6.28 miles per 24 hours or .25 miles per hour faster or 0.3 feet per second. At 1 G rocket acceleration, this equates to saving 0.01 seconds of rocket propellant

[@ericsmith6394]

Wouldn't it be great if they had a mile of launch track to abort when one of the main stage engines doesn't light?

[@mred8002]

I read about that concept in one or two of the early science fiction novels, when several authors actually were engineers and scientists and could do simple math.

[@douginorlando6260]

@@mred8002like in the classic Sci fi movie “When Worlds Collide”. The rocket launched sideways on a ramp that pitched up. Except in the movie the rocket burned its own propellent to accelerate on the ramp.

[@mred8002]

@@douginorlando6260 That sounds right. Their evacuation ship. There was another that may have been Japanese, that had side or bottom rockets? Now, why can’t I recall a film I saw once almost 70 years ago?

[@Mariuspersem]

Pretty excited about the next episode, the jet engine question is something that plagues my mind. If I could guess they probably produce too little thrust

[@JohnR31415]

And you’ve got a whole different fuel system to deal with, so extra tanks etc… Mass is probably one of the biggest reasons.

[@thestellarnet8887]

Yea once you get to space the engine is basically dead weight. not even space really, the best of fighterjets can only reach 70-90 thousand feet and the karman line is 330 feet and GST even higher. Thus the first stages would have to be ejected seconds after launch which just isnt economic. Main reason is really that those engines need air to function and yes their thrust to weight ratio isnt good enough @@JohnR31415

[@JWQweqOPDH]

Burning air instead of lox allows dropping the weight of the lox tank, but your engine needs to be absolutely massive to produce the required thrust. Think about the fuel pump on your car or on a jet plane: it's some small part you rarely see or think about. With rocket engines they're mostly fuel pump. A jet engine of the same thrust would require a similarly sized fuel pump, and the proportions would still be the same as other turbojet engines so the air compressor and turbine to power it would be absolutely massive. We're talking bigger than a gas turbine power plant.

[@mikeconnery4652]

The Russians did that and they said it was a very fast rocket.

[@EveryoneWhoUsesThisTV]

Jet engines work in the bottom 10-12 km of atmosphere. So, a runway launched spaceplane can use them to get up some serious speed in preparation for orbit. But a rocket passes through that section of atmosphere too fast to take much advantage of it. That's why we don't see shrouded rocket engines going to orbit, they weigh more, but only provide doubled thrust for a small part of the trip.... :)

[@michaelbond569]

I was just on pikes peak this weekend!!! Super crazy to have you mention it as well!

[@jorgemanzanares6444]

Happy to see you online again. I mised your videos❤ 🇦🇷

[@YonHASH]

I love the fact you have switched to the metric system. It's so unusual to hear an American using meters and not miles, inches etc. Love it!

[@Shadare]

It still throws me off when he uses metric tons without specifying, probably because hes american, but they aren't THAT much different so it's w/e

[@brucelytle1144]

The math just gets easier with metric. Too many Americans don't get math in the first place! (I'm an American)

[@VAXHeadroom]

NASA actually specifies using metric for all satellites and launch vehicles. I joke that works for everything except pressure because nobody groks Pascals...

[@lanesaarloos281]

Metric is not optimal for people to visualize or relate to weight speeds or distances especially kids. 1 inch about a thumbs width, a foot a yard 1 stride. Streets and road grids are broken up in portions of miles, Metric lost two world wars and the race to the Moon..about 250 000 miles from Earth equivalent to about 10 times around the earth..simple for all to visualize.

[@joyl7842]

10:04 Tim missed the opportunity here to point out how insanely large Russia, Kazakhstan and China are - yet they operate this way.

[@rohitwankhede9153]

For russia tho at least vast majority of it is unhibited wilderness Where it wont be a issue

[@rohitwankhede9153]

I still dont know tho like what if a launch faliure from kazakstan would prob be in the steepes of northen chaina and mongolia again not very inhibited

[@rohitwankhede9153]

Chaina... idk Tho a faliure from coast would cost more lives due to thier weird coast hugging population density

[@mattcrad8605]

When I worked at Kwajalien Atoll in the Marshall Islands, Space X launched a few Falcon 1 rockets. We were about 700 miles south of the equator.

[@nickychimes4719]

Wow! You didn't pop up in my feed for ages! And i am a subscriber

[@EverydayAstronaut]

Well I’m glad you found this one!

[@witchdoctor6502]

Love this throw back to OLF times. Why don't they just build artificial mountain on equator to lunch from there? The mountain can be a sort of railgun barrel to add even more power to it :D

[@zsigmondfeher4624]

Yeah, super clever idea, your a genious

[@zsigmondfeher4624]

Also lunch is crazy

[@witchdoctor6502]

@@zsigmondfeher4624 finally some who recognized it! and yeah should've been launch not lunch

[@peterfireflylund]

@@zsigmondfeher4624might even be a level 2 super genius! You should ask Elon for a job.

[@chadford88]

Tim - I think you are one of the few that actually uses SI units - please keep it up! Every time I hear people talking about rocket velocities in mph I want to scream.

[@peterfireflylund]

Mph might as well be “bananas per hand egg game” as far as I’m concerned.

[@Mike-oz4cv]

Especially since the numbers are unimaginably large anyway.

[@AurynGaming]

So while this video answered many questions, it opened a few more. What about, in theory, launching from a Pike peak size mountain on the equator or the north/south pole depending on orbit needed? Would adding both benifits together make the negaitive worth it?

[@iamarobotninja]

Great vid as always, thank you. Also Tim, you're lookin fit bro

[@Thomas-lw1ct]

Love your videos Tim ❤ I follow you since 2019 and you truly inspired me.

[@mabbasi_of]

I am director of CESI research center in Ecuador and I can tell you clearly: it is in making When there is something to talk about, I will write about it on my LI

[@bingrusginckle]

i like rockets

[@eamonia]

Haha! That thumbnail had me rolling in the floor. A Saturn V launching off the Madderhorn. Haha...

[@JS-TexanJeff]

Good informative video Tim! Would be nice to add a bit to explain the cost (payload expense) of launching rockets to the west (like Vandenberg AFB). How much payload capacity is lost to overcome the earth rotation to insert a satellite into orbit? (or do they only do polar-ish type orbits from there? I don't know!)

[@coreysuffield]

polar-ish from vandenberg for most launches, as they can launch southward over the pacific ocean

[@camron1103]

Why don't they just fly the ring to Mordor?

[@jpeterd92]

Why don't they just give Mars rovers a broom to sweep off their solar panels?

[@SOLIDSNAKE.]

Lol wow for real, some geniuses huh

[@patricj951]

Interesting video! I actually thought the gain would be more significant by launching from mountains. But this video very well explains why it is not with all costs included.

[@askmaxim]

Tim good job as always!

[@theaureliasys6362]

Another reason is: geo politics

[@bhaskararaka]

I hope for the part two of this series you also touch on the idea of combined-cycle engines like the SABRE engine that envisions marrying airbreathing engine with a rocket engine and having the advantage of both

[@MarcelHuguenin]

Great video Tim!

[@Jasper_Seven]

looking forward to part two. After this one, I'd be looking at South America, just north of Belem to create a giant complex to receive ships, repair/refuel and launch. If I were planning, it would be 100 year plan with lots of flexibility. Payload is king.

[@nickc9590]

Brilliant. I'm repeatedly explaining these principles to folk and the trade space. This was superbly done in the video. It's all about the deltas. Cost, performance, and risk.

[@BillBakerB]

Wow, fantastic video! A look inside these two companies that IMO balances fairness and affection. Plus what a road trip for the ErdayAstro crew! Great work team - on-site reality, good interviews, infectious enthusiasm, and great compare-and-contrast.

[@anoninunen]

Step 1, settle on a reliable reusable rocket. One pad, one set of parts. Step 2, equatorial volcanic pacific island. Easy shipping for bulk components. Build rockets on site, build space stations on orbit. Fewer satellites, easier repairs, drydocks for spaceships. Step 3, containerize

[@MrAnman1985]

Awesome video, good information, the equator also has issues weather wise i think, The equator i think everywhere is tropical environment, im not sure how much this matters but the humidity is very high which could potentially be risky for flight hardware, i know it causes havoc with heavy equipment operating in the tropics and also there is a vast amount more thunder and lightning storms at tropical latitudes which would mean the potential for increased scrubs

[@KrogerKing]

Great video, keep it up!

[@knivetsil]

Just discovered this channel. Really awesome content, but my first reaction was “Wow, when did Wil Wheaton get so knowledgeable about space/rocketry?”

[@chrispbacon4519]

A novel I really enjoyed, "The Halls of Avienne", had Mt Chimborazo in Ecuador as the anchor point for a space cable. Not sure being on the west coast of the continent would assist so much for taking advantage of gravity and keeping off populated areas, but it sure sounded good for a skyhook!

[@Jackissimus]

This made me think of another topic related to launching from high mountains - StarTram. Could you make a video about that? Almost no one else has.

[@kdog290]

Just bought your spaceX model rocket. Guess its a christmas present for myself lol. I can't wait to have that beast on my desk. Thanks for all your detailed and entertaining work!

[@_dylankiefer]

Here from the stream, I only watched the first few minutes before so I figured since you shouted this video out so hard I'd check it out and it's entirety, "to understand"

[@SajjadFilms]

As always awesome video.

[@davidscates3231]

Hi Tim. A technical question if I may. The latest jet engines use bypass technology to boost thrust, drawing in air and using the heat of the exhaust gasses to expand the air and increasing the mass flow. Admittedly it could only be used for the first few minutes of flight but that's when the greatest thrust is needed.

[@timkirchoff3869]

That is the basic premise for Virgin Galactic use of a turbo fan equipped lifting airplane to more efficiently launch their "spaceplane". However, the rocket on the spaceplane doesn't ignite until it is released from the plane. As for attaching the jet engines directly to the rocket, II would assume the extra thrust provided would quickly diminish. With a rocket going almost straight up, the jet engines would quickly run out of air to ingest. I suppose they may be a bit helpful until the rocket reached supersonic speeds or to 60-70K feet (whichever comes first).

[@TheEvilmooseofdoom]

There is always a trade off, is the extra cost complexity development time and failure points worth it for just a few minutes?

[@arnaudbouret5562]

@@timkirchoff3869 Supersonic speeds arrive first, and Max-Q tends to happen below 20km. Massive air intake in rapidly thinning air around Max-Q looks challenging...

[@davidscates3231]

My thought was to induce air into the exhaust gasses of the rocket, not to add a seperate jet engine.

[@arnaudbouret5562]

@@davidscates3231 And this is what happens when one replies to a reply without keeping in mind the original comment they replied to. My bad.

[@enriquesnetwork]

I love your vids! freat day everyday that u upload :)

[@IgorTsvetkov]

Thank you for the great content! Please create a video about what it takes to reset a rocket after a mission abort. How do they unload the fuel and how do they make sure it is safe for humans to approach the rocket after a launch abort. What do they do in cases of stuck valves?

[@adieaf61]

Absolutely brilliant explenation!

[@floydbertagnolli944]

Very educational. Thank you.😊

[@vish9679]

Great video. India's ISRO similarly launches from very close to the equator (~14°N) and from their east coast. For a long time they only had polar launch vehicles and it was surprising to learn that such a location then actually becomes a detriment.

[@jeremylefevre9828]

I've actually asked myself similar questions. Basically this is what I've found: 1. Launches near equator - That's already a thing. Cape Canaveral Florida and Guiana Space Center are both examples of that. It can't be cheap for Europe to be sending rockets all the way across the ocean to a spaceport there, but they do, making me think there must be a practical and economical advantage of some kind. 2. Launches from mountains - Not really a thing to my knowledge, probably because velocity/kinetic energy counts a greater amount than potential energy when dealing with rockets. Every little bit helps I suppose, but remember you'd have to build infrastructure or use a mountain with pre-existing infrastructure. Most mountain roads are not suitable for semi trucks, let alone oversize loads required for shipping large rocket parts for final assembly at the top of a mountain. You have to build the road AND powerlines AND a rocket building facility AND a launchpad at the top of a mountain, not cheap for minimal increase in starting energy. 3. Air launching - Already a thing as well, but requires a large, expensive, complex airplane usually, and the benefit might not outweigh the added costs, at least not in every case (I'm actually going to be doing some analysis on this one when I get a chance. With a separate air launch vehicle, this MIGHT be worth it. Combined with a rocket stage, my analyses, if correct, seem to indicate usually not worth it due to lower thrust to weight ratios of turbines, ruling out systems like Star-Raker/Tu-2000, which was very counter intuitive to me.) 4. Slingshot/Maglev - These ideas are taken mostly seriously from what I can tell, and might actually be feasible. Initial investment would be very high though. Rockets don't much like lateral stresses because they tend to be long and built for compressive loads, not high bending loads, requiring you to change the design if your maglev starts horizontally and then points upward. There are challenges associated with them, but challenges that might be solvable. Spinlaunch is trying to make their design work. 10,000 G's at takeoff? Wouldn't be my first guess at something that would actually work (and not useful for astronauts, as 10,000 G's, even if for a very short time, is probably not survivable). Other possible "Why don't they" questions: 1. Energia Uragan glider/Adeline/Krylo-SV - Actually not a bad design, especially for 1980, before computers were fast enough to handle systems dynamics problems in real time without breaking a sweat. The bottom line is, it would cost about twice as much as a Falcon 9/Long March 9/Kankoh Maru, by my estimates, and therefore need a rocket with a product life of twice as long to make it break-even with current SpaceX designs. It has the advantage of not needing the engine restarted in mid-flight. If a trade-off exists where you can make a rocket engine last twice as long if it doesn't need to be restarted mid-flight, this would be the route to take. Given modern computers are more than capable of navigating a fast moving SpaceX rocket in the process of landing (a complex system dynamics problem), currently SpaceX is winning the design contest. 2. Skylon - Probably beyond my analysis capabilities at this time to perform a full analysis. A very clever idea though, trying to create an air breathing engine at lower altitudes and speeds, changing over to a rocket at higher altitudes and speeds, while also making use of lift during takeoff and landing. (From what I've seen, there really isn't enough publicly available data for me, or any average level mechanical engineer to perform a decent analysis of such an engine, probably in part due to proprietary technology deliberately kept secret to avoid losing a technological edge.)

[@Rev_Oir]

Thanks, I'd wondered why we don't launch from equatorial mountains ever since I learned about the benefits.

[@rjshadow4321]

It took me a few seconds to see the problem launching from a mountain top then thought of getting the stuff for the rocket there and winds are higher on Mountains.