7 ms·

Some quick math: 32 miles per second (see one of their linked articles, https://www.spaceflightinsider.com/conferences/vasimr-plasma-engine-earth-mars-39-days/

Some quick math: 32 miles per second (see one of their linked articles, https://www.spaceflightinsider.com/conferences/vasimr-plasma-engine-earth-mars-39-days/ https://www.spaceflightinsider.com/conferences/vasimr-plasma...) is 155,200 miles per hour. Assume you accelerate at 21 MPH, which is about 1 g (100 KPH ~ 60 MPH, 100 KPH / 32.81 KPH/S^2 = 2.85 s, 60 MPH / 2.85 s). So at 1 g It takes you about 228 days to reach cruising speed, 2 g takes 114 days, 3 g 57 days. So I don't think this would not be useful to transport space crews? Still really cool tho.

ashtonkem 6y ago
And remember that you have to bleed most of that speed off before entering orbit. Even with aerobraking most orbiters try to slow down to ~2km/s before hitting the atmosphere. Hitting the Martian atmosphere at 32miles per second wouldn't be an acceptable plan in KSP, let alone in real life.
- skunkworker 6y ago
  If this existed I would expect it would do something similar to The Expanse where they "flip and burn" to slow down coming towards the target. On the plus side, your craft could have decent "gravity" for most of the whole trip.
badwolf 6y ago
Also importantly, you have to slow down at the other end.
- dylan604 6y ago
  If your ship can only handle 1G of acceleration, would that not also mean that it could only handle 1G deceleration as well? That means starting to slow down halfway to your destination.
  - jandrese 6y ago
    I think it would be more like you time your arrival with the conjunction of some gas giants in the destination solar system and aerobrake multiple times to get your speed low enough so you can aerobrake on your destination planet. Bringing enough fuel to decelerate the same way you accelerated isn't usually practical, inflating your rocket by 15x its original size or more.
    - dylan604 6y ago
      One of my pet peeves about sci-fi is how ships jump out of FTL into a perfect orbit around a planet. The concept of temporal dampeners is laughable even after suspension of disbelief to allow for FTL.
      - rbanffy 6y ago
        Sci-fi-grade engines are always fun. If you want to jump straight into a stable orbit, just add the right velocity component to your exit point. Or select a synchronous orbit. Any sci-fi-grade navigation computer can do that.
        jandrese 6y ago
        Even a Geo orbit is an orbit. I guess you could drop out at a Lagrange point. Of course depending on hour your Sci-Fi FTL engines work you could build up speed by stopping up high in the gravity well, let the planet accelerate you to orbital velocity, then jump sideways into an orbit once you're moving fast enough.
        rbanffy 6y ago
        Or you can just use the automatic preset that puts you in a stable orbit depending on the distance from the surface you chose. The default is synchronous (a.k.a. "standard orbit"). These functions are a hard requirement for passenger transportation anyway because you need to match orbit with the station you are docking with. Protocol is to jump to a random position a couple light seconds from the port, get authorization, then short jump to your assigned docking exit point.
sandworm101 6y ago
I think you should check your math again. 155,200mph = 69,380 m/s At 1g acceleration (10m/s/s) that is 6,938 seconds. 6,938 seconds is like 2 hours. A ship that can sustain 1g acceleration continuously for periods measured in hours, that would indeed be an interplanetary drive. Sustain that for days/weeks/months and it will take us to other stars.
- ashtonkem 6y ago
  I double checked, because I originally thought you were wrong, but it looks like you're essentially right. 32mi/s * (5280ft/mi) = 168,960 ft/s 168,960 ft/s ÷ 32.17405 ft/s^2 = 5,251.4371053691s 5,251s ÷ 60 s/min ÷ 60 min/h = 1.45hr
- onlyrealcuzzo 6y ago
  How long do you need to accelerate at that pace to reach C? 299,792km/s / .01km/s => 29 million seconds? ~335 days? I'm assuming a lot of things would go wrong as you get closer to C...
  - sandworm101 6y ago
    Or go right. Time dilation would start working in your favor. You might get there, and back, within your lifetime. Of course everyone on earth would be long dead.
    - rimunroe 6y ago
      Micrometeors and radiation would be the major problem. Also, it's not just time dilation that would help. At relativistic speeds, space contracts quite noticeably in the direction of travel, so the actual distance you need to cover diminishes as well.
      - rbanffy 6y ago
        That's because you won't be locally faster than light. You may cover 4 light years in one, but only because those light years will be much smaller from your point of view. You'll never "feel" faster than light.

ashtonkem 6y ago

And remember that you have to bleed most of that speed off before entering orbit. Even with aerobraking most orbiters try to slow down to ~2km/s before hitting the atmosphere. Hitting the Martian atmosphere at 32miles per second wouldn't be an acceptable plan in KSP, let alone in real life.

skunkworker 6y ago
If this existed I would expect it would do something similar to The Expanse where they "flip and burn" to slow down coming towards the target. On the plus side, your craft could have decent "gravity" for most of the whole trip.

badwolf 6y ago

Also importantly, you have to slow down at the other end.

dylan604 6y ago
If your ship can only handle 1G of acceleration, would that not also mean that it could only handle 1G deceleration as well? That means starting to slow down halfway to your destination.
- jandrese 6y ago
  I think it would be more like you time your arrival with the conjunction of some gas giants in the destination solar system and aerobrake multiple times to get your speed low enough so you can aerobrake on your destination planet. Bringing enough fuel to decelerate the same way you accelerated isn't usually practical, inflating your rocket by 15x its original size or more.
  - dylan604 6y ago
    One of my pet peeves about sci-fi is how ships jump out of FTL into a perfect orbit around a planet. The concept of temporal dampeners is laughable even after suspension of disbelief to allow for FTL.
    - rbanffy 6y ago
      Sci-fi-grade engines are always fun. If you want to jump straight into a stable orbit, just add the right velocity component to your exit point. Or select a synchronous orbit. Any sci-fi-grade navigation computer can do that.
      - jandrese 6y ago
        Even a Geo orbit is an orbit. I guess you could drop out at a Lagrange point. Of course depending on hour your Sci-Fi FTL engines work you could build up speed by stopping up high in the gravity well, let the planet accelerate you to orbital velocity, then jump sideways into an orbit once you're moving fast enough.
        rbanffy 6y ago
        Or you can just use the automatic preset that puts you in a stable orbit depending on the distance from the surface you chose. The default is synchronous (a.k.a. "standard orbit"). These functions are a hard requirement for passenger transportation anyway because you need to match orbit with the station you are docking with. Protocol is to jump to a random position a couple light seconds from the port, get authorization, then short jump to your assigned docking exit point.

sandworm101 6y ago

I think you should check your math again. 155,200mph = 69,380 m/s At 1g acceleration (10m/s/s) that is 6,938 seconds. 6,938 seconds is like 2 hours. A ship that can sustain 1g acceleration continuously for periods measured in hours, that would indeed be an interplanetary drive. Sustain that for days/weeks/months and it will take us to other stars.

ashtonkem 6y ago
I double checked, because I originally thought you were wrong, but it looks like you're essentially right. 32mi/s * (5280ft/mi) = 168,960 ft/s 168,960 ft/s ÷ 32.17405 ft/s^2 = 5,251.4371053691s 5,251s ÷ 60 s/min ÷ 60 min/h = 1.45hr
onlyrealcuzzo 6y ago
How long do you need to accelerate at that pace to reach C? 299,792km/s / .01km/s => 29 million seconds? ~335 days? I'm assuming a lot of things would go wrong as you get closer to C...
- sandworm101 6y ago
  Or go right. Time dilation would start working in your favor. You might get there, and back, within your lifetime. Of course everyone on earth would be long dead.
  - rimunroe 6y ago
    Micrometeors and radiation would be the major problem. Also, it's not just time dilation that would help. At relativistic speeds, space contracts quite noticeably in the direction of travel, so the actual distance you need to cover diminishes as well.
    - rbanffy 6y ago
      That's because you won't be locally faster than light. You may cover 4 light years in one, but only because those light years will be much smaller from your point of view. You'll never "feel" faster than light.