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Thinking whether they could use one of the projects aiming to launch small payloads into space, sort of space trebuchets: SpinLaunch - Developing a system tha

Thinking whether they could use one of the projects aiming to launch small payloads into space, sort of space trebuchets: SpinLaunch - Developing a system that spins a payload at ultra-high speeds inside a vacuum chamber, then launches it into the sky using stored rotational energy. They claim it could launch small satellites for a fraction of the cost of traditional rockets. Launchloop - Proposed concept of using a powerful electromagnetic accelerator called a Launchloop to fling payloads into space. It would use low-cost electricity rather than expensive rocket fuel. Still in early feasibility stage. TAES - Developing a space trebuchet mechanism that uses centrifugal force similar to how a trebuchet launches projectiles. They're aiming to launch 6U CubeSats (10x10x30cm) to Low Earth Orbit for a relatively low cost per launch. Rocket Lab - Makes small Electron rockets for launching 150kg payloads to LEO. Over 20 successful launches to date and helping enable more frequent smallsat launches. Virgin Orbit - Uses a modified Boeing 747 to carry a 2-stage LauncherOne rocket to altitude, then releases and ignites to place payloads in orbit. Aims for frequent, affordable smallsat launches.

14 3y ago
None of those solutions are suitable for this mission. These satellites need to be traveling a hundreds of thousand of kilometres an hour or more. Think about voyager 1 traveling at 65,000km/hr. It is still over 18,000 years before it will reach a light years distance and this mission is talking about 4 light years. So the launch really has zero importance as does getting these satellites up to massive massive speeds. Anything less then like 1million kilometres per hour is probably just too slow. Edit: even at 1 million kilometres per hour it would still take over 4000 years to reach the full distance so really we need to be going unimaginably fast to get there.
temp0826 3y ago
Do these launchers actually make sense? Maybe from the moon (obviously not for earth orbit-destined satellites, but deeper space)
kolinko 3y ago
Launching from altitude gives you very little, so does spinlaunching. It is because it’s about speed, not altitude. Witch Spinlaunch, they plan to laumch around 5000kmph, and you need a speed of around 25000kmph to reach orbit. In other words, they would need to use their setup to launch a rocket of a size of 1/2-3/4 of size of a falcon1 to get into orbit, and even then, unless they land the second stage, they will come out far more expensive than what SpaceX is doing. The tech may work on moon, but even on Moon a different solution - similar to maglev - may be better, bacause there would be no issues with crazy centrifugal forces. Anything launching from earth will require some sort of a rocket fuel (or some new laws of physics), because even if you managed to launch at the speed of 25000km/h from the ground, the payload would slow down before it left the atmosphere.
- trhway 3y ago
  >even if you managed to launch at the speed of 25000km/h from the ground, the payload would slow down before it left the atmosphere. Project HARP was shooting 16 inch artillery shells at 2100m/s, and they reached 180km altitude, i.e. the atmosphere was slowing it down only for 15%. While higher speeds cause higher losses, the larger payloads would benefit from decreasing surface-to-volume ratio, plus if one launches from say a plateau in Andes where atmosphere is aleady thinner, I think the losses will be similar for large payloads at speeds close to orbital.
  - kolinko 3y ago
    Oh, nice, TIL. Good point about surface to volume ratio.
- rcxdude 3y ago
  Yeah, but isn't it also a lot about the tyranny of the rocket equation? The more speed you want the more mass of fuel you need to accelerate so the more fuel you need, etc. That means if you can start your ascent at even a relatively small fraction of the final speed you need the size of your rocket can shrink substantially.
  - 3y ago

14 3y ago

None of those solutions are suitable for this mission. These satellites need to be traveling a hundreds of thousand of kilometres an hour or more. Think about voyager 1 traveling at 65,000km/hr. It is still over 18,000 years before it will reach a light years distance and this mission is talking about 4 light years. So the launch really has zero importance as does getting these satellites up to massive massive speeds. Anything less then like 1million kilometres per hour is probably just too slow. Edit: even at 1 million kilometres per hour it would still take over 4000 years to reach the full distance so really we need to be going unimaginably fast to get there.

temp0826 3y ago

Do these launchers actually make sense? Maybe from the moon (obviously not for earth orbit-destined satellites, but deeper space)

kolinko 3y ago

Launching from altitude gives you very little, so does spinlaunching. It is because it’s about speed, not altitude. Witch Spinlaunch, they plan to laumch around 5000kmph, and you need a speed of around 25000kmph to reach orbit. In other words, they would need to use their setup to launch a rocket of a size of 1/2-3/4 of size of a falcon1 to get into orbit, and even then, unless they land the second stage, they will come out far more expensive than what SpaceX is doing. The tech may work on moon, but even on Moon a different solution - similar to maglev - may be better, bacause there would be no issues with crazy centrifugal forces. Anything launching from earth will require some sort of a rocket fuel (or some new laws of physics), because even if you managed to launch at the speed of 25000km/h from the ground, the payload would slow down before it left the atmosphere.

trhway 3y ago
>even if you managed to launch at the speed of 25000km/h from the ground, the payload would slow down before it left the atmosphere. Project HARP was shooting 16 inch artillery shells at 2100m/s, and they reached 180km altitude, i.e. the atmosphere was slowing it down only for 15%. While higher speeds cause higher losses, the larger payloads would benefit from decreasing surface-to-volume ratio, plus if one launches from say a plateau in Andes where atmosphere is aleady thinner, I think the losses will be similar for large payloads at speeds close to orbital.
- kolinko 3y ago
  Oh, nice, TIL. Good point about surface to volume ratio.
rcxdude 3y ago
Yeah, but isn't it also a lot about the tyranny of the rocket equation? The more speed you want the more mass of fuel you need to accelerate so the more fuel you need, etc. That means if you can start your ascent at even a relatively small fraction of the final speed you need the size of your rocket can shrink substantially.
- 3y ago