This Is a question that was buzzing me, but since every meter of altitude a rocket consume an absurd amount of fuel, wouldn't be more efficent launching rocket from higher altitudes?

Thinking to places like El Alto in Bolivia that has 4,1 km above Sea level. Even tought the microgravity map shows a slightly higher Gravity I assume It Is compensated by the higher altitude.. or not?


marked as duplicate by JCRM, Dan Pichelman, Jack, uhoh, peterh Apr 19 at 16:04

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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    $\begingroup$ It's a good question, but it's been asked before. Don't worry if your question is closed as duplicate, it's a standard function to help direct future readers to existing answers. Fell free to ask a new question any time, and Welcome to Space! $\endgroup$ – uhoh Apr 19 at 15:56
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    $\begingroup$ Not a duplicate, since that post does not really mention strategic positioning of launch sites and only considers the launch altitude. $\endgroup$ – Hans Apr 19 at 15:56
  • $\begingroup$ I dont believe its duplicate, actually the other topic did not answered to me. I readed It carefully. $\endgroup$ – GameDeveloper Apr 19 at 17:22
  • $\begingroup$ @GameDeveloper this site does a pretty good job of re-opening questions when a a clear case is made that the question is different and the question is edited to help to make it clearer what the difference is. In this case can you highlight what it is specifically that you would like to emphasize that isn't answered by the combination of those three answers? $\endgroup$ – uhoh Apr 19 at 23:33

You are correct a high launch location could help with rocket efficiency. Engines with nozzles optimized for lower atmospheric pressure, usually resulting in higher specific impulse primarily, also lower dynamic pressure and atmospheric drag. The "distance" gain is minuscule - maybe half a second worth of fuel usage, but the pressure change would be beneficial.

The problem is a set of other restrictions and requirements of a launch site.

  • Safe "downrange" area - a couple hundred kilometers preferably completely uninhabited, both for planned booster fall zone and in case of mid-flight explosion. Sea is optimal for that.
  • Politics. Not launching over another country's territory. Technically after getting over the Karman line there's no issue... but if the rocket fails to achieve orbit, it's better for it to fall onto international waters or own territory, than onto territory of a country you're in tense relations with. Also try to imagine USA launching spy satellites from a spaceport in Bolivia... The spaceport should definitely be on "home territory." (Russia is definitely not happy about Baikonur being located in Kazakhstan.)
  • Relatively flat and safe to land on, for manned launches. Launch Escape System is a great device that assures in case of trouble at launch the astronauts will be brought safely to the ground... but doesn't help a bit about where exactly and what happens afterwards, e.g. if they land on a steep slope and the capsule starts rolling down rapidly... Mountains aren't safe for landing.
  • Logistics. Many of rocket parts are too huge for land transport over large distances, and delivery by sea is often the only viable route. Also, good land transport network for all that can be transported by land - usually best developed in coastal areas.
  • Employee comfort, health and safety. People qualified to work for the rocket industry are top professionals who'd easily find work in more hospitable areas had their workplace turned out to be too inhospitable - like high altitude settlements often are. You can bet warm beaches of Florida are more welcoming than Bolivian highlands.
  • Economy and economical politics. The spaceport is supported by a whole lot of industries big and small and stimulates the economy immensely. So you want it to be domestic for this reason. Bolivia can't afford own major spaceport. USA could have one in the Rocky Mountains, but - range safety! It would be very hard to find enough safe uninhabited terrain to assure safe 'drop zone' for the spent boosters etc.

  • Local development, economy, industry and infrastructure. It's much easier to have a spaceport near existing manufacturing facilities of firms that operate or are capable of operating producing the rockets, than to have the rockets transported across half the country - or build the entire production infrastructure from scratch at the site. Again, coastal areas tend to be most developed in these domains.

As result, the benefits of high altitude don't outweigh the costs of otherwise awkward location.

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    $\begingroup$ The U.S. initially launched V-2 rockets captured from Germany after World War II from White Sands, New Mexico, close to the border with Mexico. The rockets were launched toward the north, away from the border. A rocket launched in 1947 lost control, veered toward the south, and crashed near Juarez, Mexico, just a short distance from an ammunition dump at which Mexican mining companies stored powder and dynamite. The lesson-learned from this accident was that not causing international incidents or killing citizens with failed launch attempts is a good idea. $\endgroup$ – David Hammen Apr 19 at 16:12

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