3 ms·

In case it wasn't clear, specific impulse is more or less equal to fuel efficiency for spacecrafts (higher is better). My experience playing Kerbal Space Progr

In case it wasn't clear, specific impulse is more or less equal to fuel efficiency for spacecrafts (higher is better). My experience playing Kerbal Space Program, if accurate, suggests that such an engine is more effective for longer term missions, because the increased SI comes at a cost of lower max thrust (I.e. it takes longer to accelerate); I suspect this is not very accurate IRL as all our missions take a very long time so this problem may be irrelevant. Also looking below it seems such an engine is limited by electric power (solar panel/battery). Hence this leads me to believe this type of engine allows us to extend the range of our missions but at the cost of longer mission durations.

outworlder 11y ago
> My experience playing Kerbal Space Program KSP's ion engines are WAY overpowered to make for better gameplay.IRL thurst is lower by orders of magnitude. If we are talking about probes in the solar system, then the mission durations are already long to begin with. Instead of firing a conventional hydrazine-based thruster for a few minutes, we'll fire an ion engine for months. But, if it takes years to get where you are going, who cares? There are things we can't do yet, such as orbital insertions, with ion engines. In these cases, conventional engines are better.
- avmich 11y ago
  > There are things we can't do yet, such as orbital insertions, with ion engines. We can do orbital insertions - if we approach a planet or asteroid with parabolic speed, we need only small change to get to an elliptic orbit, and that orbit can be later shaped as we need. What we can't do is a launch or landing with bodies with sufficient gravity - like Moon or Vesta. There we don't have time to accelerate.
- david-given 11y ago
  Plus, as real life ion engines have burn times on the order of years, and as KSP can't do (adequate) time acceleration while the engine is running, there's a bit of an incentive to build high-thrust short-burn spacecraft --- I don't really want to have to babysit a burn in real time for six months. (This also disqualifies solar sails, which is a shame, because I'd love to play with them.)
  - outworlder 11y ago
    Sort of. People have figured out a way to simulate constant acceleration while the spacecrafts are "on-rails". I believe the KSPi mod has solar sails. They are not very realistic, but probably good enough for a game.

outworlder 11y ago

> My experience playing Kerbal Space Program KSP's ion engines are WAY overpowered to make for better gameplay.IRL thurst is lower by orders of magnitude. If we are talking about probes in the solar system, then the mission durations are already long to begin with. Instead of firing a conventional hydrazine-based thruster for a few minutes, we'll fire an ion engine for months. But, if it takes years to get where you are going, who cares? There are things we can't do yet, such as orbital insertions, with ion engines. In these cases, conventional engines are better.

avmich 11y ago
> There are things we can't do yet, such as orbital insertions, with ion engines. We can do orbital insertions - if we approach a planet or asteroid with parabolic speed, we need only small change to get to an elliptic orbit, and that orbit can be later shaped as we need. What we can't do is a launch or landing with bodies with sufficient gravity - like Moon or Vesta. There we don't have time to accelerate.
david-given 11y ago
Plus, as real life ion engines have burn times on the order of years, and as KSP can't do (adequate) time acceleration while the engine is running, there's a bit of an incentive to build high-thrust short-burn spacecraft --- I don't really want to have to babysit a burn in real time for six months. (This also disqualifies solar sails, which is a shame, because I'd love to play with them.)
- outworlder 11y ago
  Sort of. People have figured out a way to simulate constant acceleration while the spacecrafts are "on-rails". I believe the KSPi mod has solar sails. They are not very realistic, but probably good enough for a game.