The European Space Agency have a launch site within 5 degrees of the equator and during launches the commentators will usually remind the audience of how big an advantage this offers, but, how much difference does it really make?
I think this particular video would have really benefited from a side by side comparison of the delta-v's in question. When you say (paraphrased) "Since we have xxxx remaining delta-v, it's clearly better than before." It's not clear, because there were so many numbers rattled off in a short time I can't remember which one was important! Just a chart showing the improvements/differences between the three sites, and the final delta-v remaining, would have made a world of difference.
thanks! many KSP players dont really know this since KSC is at the equator. I think squad should add multiple launch sites in the stock game so the player has something to compare against. Or this could even be influenced by the difficulty settings: easy- equatorial launch, medium- non equatorial launch like Kennedy space centre, and hard- high latitudes with restrictions to launch direction (Baikonur)
AlienChicken It's true that the equator bulges, but the atmosphere is also thicker there. However, Scott previously did a video on launching from mountains versus sea level, and I doubt the bulge makes much difference.
well technically it does bulge slightly. So I guess that guy gets points for being half right even if he kinda drew the wrong conclusion. If trying to min max a launch a tall mountain on the equator would be the best from a dV standpoint. Sadly practicality stomps all over that as not every country has access to the equator let alone a mountain with the possibility of building launch infrastructure on it.
As a French I can tell you that the main reason of this geographical location, is Geostrategic. It's to bring some economical activity on a very far away and poor part of France, and to have a continuous presence in South America, to claim in geography books that France have a border with Brazil. This base could have been placed in many other places like French West indies or even rent the launchpad to our American friends.
In case anyone wants to look it up, the regular transfer is called a Hohmann transfer; the "go up higher, then com back" is called a bi-elliptic transfer. en.wikipedia.org/wiki/Hohmann_transfer_orbit en.wikipedia.org/wiki/Bi-elliptic_transfer The simple explanation is that it takes way less delta-V to do basically anything in a high orbit. So if you go up high, align the plane there, then come back low, it might actually come up lower as a total sum, because your alignment change was so much cheaper.
Hey Scott. We added the node merging in the dev build a few days ago :) You may also want to have a look at the special RO branch ( ksp.sarbian.com/jenkins/job/MechJeb2-RO/ ) and its new PEG launch ascent code + auto launch clamp stage when reaching the proper TWR ( github.com/lamont-granquist/MechJeb2/wiki )
Waigeo Island, or the smaller Pulau Manuran (island) just to the north of central Waigeo, both on the equator in West Papau New Guinea . East coast of Waigeo looks like a good place for a launch site. 0*11'51" by 131*17'48" lat and long in Google Earth is the area for a launch site on Waigeo that looks possible. Launching east and slightly north with no land in the way until South America. A hill or two towards the ocean would be nice for tropical cyclones, so in those hills looks good to me for a few launch sites, support buildings in the valleys or on the coast. Also up high enough to not worry about Tsunamis in that part of the pacific is probably a good idea. Manuran island looks very nice for a launch site as well. It already has the perfect area industrially developed somewhat. I think it's actually a small mining operation for some low value ore, but it could be that a semi secret launch site is being developed slowly on Manuran, just initial land clearing and grading, at 00*01'04" by 130*53'16" They both have thousands of miles of open ocean downrange. If Pulau Manuran is used, I hope the epic left in the reef pass on the east side isn't closed to surfing, would be a shame.
A quick unrelated tip! If you have a payload that is really long you can make an internal truss and strut stability structure that lines the entire payload to make it rigid and it wi'll then be detached with the payload decoupuler
Actually, due to the Tsiolkovsky Rocket Equation, (and if my equations are correct), that 60 m/s (1.7%) delta V difference to LEO amounts to a 5% decrease in payload mass. I'm also wondering, does the ideal launch site for going to the Moon or outside the Earth's sphere of influence change back to Florida, because the launch can be lined up with the ecliptic/lunar inclination?
Scott as always you re doing a great job explaining stuffs that i dont understand yet making it very interesting subjects d'or thé matter , not understanding crap is only coz i am dumb when it comes to maths! Now i do remember an old vidéo where you said that space rendez-vous were done completely differently in thé réal world: would you dig into this for thé pebs like myself whom are incults? That. Would be a very good subject for a video from you, at least from m'y point of view...
When SpaceX launches to geostationary orbit, they only do 2 second stage burns. One to get into orbit, and one to put the satellite into GTO. So does that mean that the satellite does the circularization AND the inclination change with its own fuel at apogee?
That right. More precisely, the launch inject the satellite on a GTO (Geostationary Transfer Orbit). Usually, satellite have a (Quick Apogee Engine/rocket). Its a bit different if the satellite is completely electrical.
Right and that's the reason why SpaceX (and others) try to put satellites above GEO hight (36.000 km). There the satellite needs less deltaV to perform the plane change & raise of perigee (as Scott pointed it out). For example: Thaicom 8 had an apogee of 91.000km after the seconde stage burned out. Less deltaV used -> more fuel left -> longer lifetime -> happy customer
When I'm doing capture burns and I need a large inclination change, I'll try and get my periapsis close to the ascending/descending node while still a long way out, then burn just enough to close my orbit, and do the plane change at apoapsis when I'm only going maybe 10m/s, so it basically happens for free. Just takes a long time to wait for the orbit.
moosemaimer yes, that's a good idea. But this is different, since we're starting in a lower orbit, you can't get in such a high orbit without burning extra fuel, more than you would save by having a small inclination change maneuver.
Scott you need to make a video explaining how to get into orbit with the parts unlocked in early avionics and early orbital rocketry ( realism overhaul and RP-0)
The combination of two burns would be a simple Vektoraddition, not even a Skalarproduct or Vectorprodukt. I often let MechJeb calculate the needed burn for an Apoapsis/Periapsis change and write down numbers close to that and then delete the maneuver, tell MechJeb to create a planechange and adjust the maneuvernode accordingly.
I've noticed that SpaceX (at least) GTO also have a perigee above GSO altitude. Because of the glories of playing Kerbal Space Program, I guess that it was to save on the plane-change.Now a real steely-eyed missile-man (which I am not) would know how to find the optimum altitude to shoot for. I'm sure the pros have done this and their orbits are pretty good.
Scott, I just watched the video you made about how close can we get to a black hole, and I wonder since on earth it is theoretically possible to go into space at the speed of a bike, if we keep the uprising force going. So is it possible to do the same thing inside the event horizon, and once the spaceship is out of the event horizon, we can perform burn to achieve an orbit around the black hole outside the event horizon? Is that a kind of way to escape?
You would need an immense amount of energy to get that going vertically and into orbit, even at the speed of a bike. I mean, you need to constantly accelerate a spaceship while being pulled down by the gravity of a *black hole*.
sadly that won't work. you can't escape a black hole because the escape velocity is greater than lightspeed at the event horizon. Scince you can't accelerate to lightspeed, you wont be able to "climb" out of or even just away from the black hole.
Markus Mines I understand that, but on earth if we don't turn the power all the way up a rocket can still reach space at 5m/s, even the escape velocity of earth near the surface is close to 8000m/s. What I am saying is that we do the same thing inside the event horizon, raise up at 5m/s even the escape velocity is more than the speed of light. When we raise out of the event horizon, and now we are in a region where you can orbit the black hole with the speed less than the speed of light. Now we fire up the engines again to orbit the black hole.
While your thinking is correct, sadly it doesn't work like this. For this to work, you'd either need a constant acceleration higher than physically possible upwards or something to "push off" off. Both are impossible in a black hole. Apart from these reasons the main reason this doesn't work is the (hypothesized) nature of spacetime inside the event horizon. You see, time and space sort of switch places and where you can only travel in one time "direction", the future, outside the event horizon, you can only travel in one space direction, towards the singularity, inside the event horizon while possibly being able to traverse time in any direction. So attempting to escape by moving would possibly send you into the future or past but always closer to the singularity. Check out PBS Spacetime here on RU-vid, they explain these things better than i do.
To all the others that have commented, yes... though it does make a difference from where you launch. When you take into account the gravity of the planet you're trying to launch from its insignificant.
I think you've missed out the other big advantage to equatorial launch. 12 to 18 long duration super easy launch windows per day to a space station in LEO. Such a station would not be very good for earth observation, but if you want to build or stockpile anything, that kind of launch/recovery opportunity makes things a lot easier.
I tried to read through the comments so maybe this has been asked already.....all this assumes that you geosynchronous at the equator....is it different or possible if you chose another plane? If so then does it still make since to launch from the equator?
Well, tecnically the Alcantra Base of the Brazillian space agency, is closer to equator, with only two degrees, but the brazillian rocket it suferring major setbacks since 2003 and with no publuc suport it will take at least 3 to 5 years to flight in it's simpler version. Also there were plans to launch the Ucranian Tsyklon rockets from there, which never were realised. But now it seems that NASA is interesed in using the facility.
So how do we keep geostationary satellites geostationary? The gravity of sun, moon and perhaps something else could change the orbit of the satellites a bit, and then it won't be a perfect geostationary satelite... Pls Scott I just need to know(._. )
Fred Heil SSTOs work, but they can carry very little useful payload mass. To make them work you'd need either much higher ISP propellant, and/or much lower mass materials for the mechanical structure.
Scott Manley can you talk about launching from a greater height as compared to closer to the equator ie would it be better to lunch from mt everest may be or some other mountain
winged that's not the reason. Just watch a SpaceX launch to GTO for example. They need to cut the engines after reaching LEO and coast for about 15 Minutes before relighting the engines to boost to GTO in order to have perigee and descending node aligned. Another thing KSP taught me.
The rotational or angular speed of the earth is the same everywhere. Rotational speed is measured in rotations of an object over time, so no matter where you are on earth, the rotational speed is 1 rotation per day. Linear speed what they should be saying, which is the speed of a point on a rotating body moving in relation to the center of the object.
What if you skip the LEO part? Could there be a (highly eccentric) orbit straight from Baikonur to a point on the geostationary orbir? From there, you should have a negligibly low velocity, and you'd be circularizing your orbit from rest, no matter where you started on Earth.
No, it doesnt work quite that way. The manouver you described will put you not on geostationary orbit, but rather on a circular geosynchronous orbit with a certain minimal inclination, which is proportional to the lattitude you started on. You still need to correct inclination. Such a mnouver will only put you on geostationary if you start on the equator.
Hey Manley KSP fans. This guy has got me wanting to play again, but I don't want to do the old career. Are there any good mods for a different career experience from the stock?
It will help a little in reaching polar orbits because you'd hardly need to shake of any angular momentum, but those hypothetical launch sites are in the middle of ice-caps and that are hazardous locations that are also hard to reach.
Well, that 600m/s saved is pounds and pounds of rocket fuel. At around $10,000 per pound to put into space, or at least in this case to BURN into space, its also more cost effective (even if you're spending the same about of money into both identical rockets)
I think you may have done it already but I can't find it. You show the savings launching from the equator but what if a launch happened from the top of Kilimanjaro, about 6000m. Altitude + Equatorial launch.
David Campos a polar orbit would defeat the purpose of a geostationary orbit. The whole point is to be over the same spot on Earth at all times, but if you're in a polar orbit, this won't happen.
I was thinking about that as well. Probably because more people know Kourou than they do Alcantara, even though it's a little closer to the equator than Kourou.
The difference between any place between the arctic/antarctic circles isn't all that much, if you're going east. What's a real pain in the ass is a launch into a polar orbit from Vandenberg, in which you lose the free 4-and-change km/s boost provided by the rotation and have to make up for it with fuel, or the rare (but I'm fairly sure I read that there are a few) retrograde orbit, in which you (presumably) need about 9 km/s more delta-v than an eastward launch.
I am wondering if people are lighter because of this rotation when standing at the equator, or if the slight bulge there is responsible for an increase in gravitational pull, leaving them at the same weight as anywhere else on the planet
The further you are from the center of gravity, the lighter you are. But the difference between, say, French Guiana and the shores of Iceland is so fractional it really doesn't make a difference.
Scott can you do the same for a sun synchronous orbit? I think they are against the rotation of the earth and launching near the pole should be more efficient.
Sun synchrounous? Like travelling around the sun on earths orbit? an orbit around the earth that positions the sattlelite always between earth and sun? Or on a heliostationary orbit? I'm not sure if a synchornous orbit around the sun with a period of 25.38 days would even be outside the sun. For an orbit aroound the earth that always sits bitween earth and sun, there is actually quite the amount of objects placed around us. And it heavily depends on the inclination of the orbit.
A Sun-synchronous orbit is a near polar orbit around Earth. Many earth observation satellites use this orbit, because they see the earth surface always at the same local time (e.g. 10 am). en.wikipedia.org/wiki/Sun-synchronous_orbit
Sun synchronous orbits are always in the sun and will pass over a place at the same time everyday. They work by shifting the orbit forward slightly using the distorted shape of the earth at the equator.
This is still only 400m/s out of... how much total delta-v? About 4%? Wait, ARE there more costs operating on/near the equator? One of the costs is the launch pad getting too cold which even happened in Florida (very unusually) is it ever too hot to launch? I suppose the biggest factor is infrastructure, getting all the technicians and equipment there, is an equatorial launch site too far from where the heavy industry and technicians are located.
Only interesting if you need the ability to launch into any polar orbit 24/7? Like launching missiles to destroy satellites, and causing subsequent Kessler Syndrome.
Well you would not launch from Plesetsk to a geostationary orbit as Baikonur or Vostochny are better. However to polar orbits, it is better to be further north.
The japanese launch some rockets not directly straight up, instead, they tilt the rocket slightly downwards. Has this anything to do with this mechanic phenomena? Thank you Scott.
You didn't watch his videos about small rockets? Anyway, the japanese do this because in this way they do not put any complex (weapon grade) navigation system in their rockets, meaning they can freely send rockets to space and not get a full comitte on their asses for developing military technology (they still have to deal with post-war negotiations of surrender and this kind of stuff). The tilt you see in their rockets is to manually set the gravity turn on it without the use of active controls.
And the Japanese have been making use of that tilt since the latter half of the 1950s... back when they were still flying experimental/sounding rockets. After 2006, only sounding rockets use that tilt (aside from the recent failed SS-520 orbital launch attempt, but that's another topic for another day).
For this video you used the exact same rocket in all tests. But I'm guessing that IRL you could get bigger payloads in the same rocket or save a bit on the fuel and the extra fuel to bring up that fuel
I thought Russia uses Molniya orbits for their satellites rather than putting things in GEO like most do, how much Dv does that take compared to launching from Kourou into GEO?
But didn't the erstwhile USSR and currently Russia also use the highly eccentric and high inclination Molniya orbits to cater to very high latitudes from where using geosynchronous satellites becomes increasingly difficult due to their low inclination in the sky? Molnya orbits are necessarily highly inclined and therefore may not even require any inclination correction from Baikonour! en.wikipedia.org/wiki/Molniya_orbit
To be honest... Kennedy is pretty far South as one can come i The US. IF they would have launced from mainland France it would be quite a bit far north
Let's simplify this equation. Man and Truck. Man runs towards a speeding truck = Amusing result "Like you got hit by a truck". Man runs away from a speeding truck = Amusing result "Get dragged and yes, like you got hit by a truck". Running towards a moving object = More boom. Running from an object = Less boom + Drag. But ultimate conclusion here young grasshopper is "Don't judge a dictionary by it's wrapping paper".
Because there isn't any part of the United States that is on the equator. The rotational velocity in Florida where they launch is about 1,468 m/s. At the equator, it's about 1,670 m/s. The costs of having to ship all the launch vehicles to the equator for launch greatly outweigh the savings in fuel when you're only saving about 200 m/s of delta V.
I know that; I assumed that it would therefore be obvious that I wasn't talking about the US, but rather about French Guiana. It seems that that is not a good assumption to make.
There are no parts of French Guiana on the equator either. It's southern-most region is still about 2 degrees north of the equator. It ranges from there to about 5.5 degrees north. In either case, the difference between the rotational velocity between the part of French Guiana closest to the equator and the part that is farthest is about 6.7 m/s. It really doesn't matter where you put the launch pad. A slight breeze has more of an impact on the delta V requirements than its location within French Guiana does...
Well, 1% less to go into orbit means the rocket can have 1% less fuel. 1% less fuel makes the rocket lighter with increases the thrust to weight ratio, which acellerates the rocket faster. A faster acellerating rocket needs less fuel to go into orbit. Less fuel needed means the rocket can have less fuel. .... Under the right circumstances the saved fuel can go up exponentially. Ofcourse there are limits to it. There is still other mass on the rocket. But 1% fuel savings can give more than 1% more efficiency.
HappyBeezerStudios - by Lord_Mogul Most rockets aren't purpose-built for one given satellite, and that 1% extra fuel gives extra payload cap, which is always welcome.
Of course geostationary communication satellites aren't useful to Russia anyway... They have Molnyia (probably butchered the spelling) orbiting communication satellites instead, which their launch sites are more efficient for anyway.
Scott: 1How often did you repeat the starts to measure? 2i cannot understand that an experienced Rcoket scientist like you says, that his measure is accurate because the 60m/s in DeltaV is the same difference as in earth rotation speed. the rocket wastes quite all its thrust at the start to go up. but but the higher tangential speed at the equator helps a lot to save additional fuel because less fuel for overcoming gravity must be expended.
Then we'd be launching from Brazil or further south, and the stuff in orbit would never be in shadow since the sun would be between the earth and moon. You'd also be able to see the apollo landing sites with a hobby telescope since it would be so easy to get to and so close to see in detail. But if Earth is flat, then space is fake. Can't endorse just half a conspiracy =)
