Radiation Pressure?

[intelliCom]

Considering how RTGs have a miniscule amount of force in the form of radiation pressure, should this be implemented in KSP2, at least as an optional feature like plasma blackout?

It'd be interesting to utilise the RTG's radiation pressure for maneuvering . I can imagine the trajectory already being charted based on your spacecraft's orientation, and changing that orientation changes the trajectory. Could provide a way to precisely adjust fly-bys past planets without using the spacecraft's fuel.

Then again, it's difficult to predict the magnitude today, so maybe it requires a tracking station upgrade?

[Bej Kerman]

If you had a few millennia to spare, I'm sure you could push a half useful amount of thrust out of a set of RTGs. I wouldn't bet on the devs bothering to add such a miniscule feature.

[intelliCom]

2 minutes ago, Bej Kerman said:

If you had a few millennia to spare, I'm sure you could push a half useful amount of thrust out of a set of RTGs. I wouldn't bet on the devs bothering to add such a miniscule feature.

Fair enough. Just a thought. RTGs admittedly don't have much radiation pressure, but maybe a nuclear reactor does?

[daninplainsight]

On 8/18/2022 at 10:36 PM, intelliCom said:

Fair enough. Just a thought. RTGs admittedly don't have much radiation pressure, but maybe a nuclear reactor does?

It's, once again, likely to be miniscule. One of the biggest design considerations of a nuclear reactor is making sure that most of the radiation stays inside shielding, and I would actually make an assumption that escaping radiation would leave in a symmetrical set of directions, so there wouldn't be a net "radiation pressure" in any particular direction. In real life over the course of many years an orbiting reactor might drift a little due to the momentum of escaping radiation, depending heavily on the exact design of and wear on the reactor but it would be absurdly difficult to model in the context of KSP.

[intelliCom]

12 hours ago, daninplainsight said:

It's, once again, likely to be miniscule. One of the biggest design considerations of a nuclear reactor is making sure that most of the radiation stays inside shielding, and I would actually make an assumption that escaping radiation would leave in a symmetrical set of directions, so there wouldn't be a net "radiation pressure" in any particular direction. In real life over the course of many years an orbiting reactor might drift a little due to the momentum of escaping radiation, depending heavily on the exact design of and wear on the reactor but it would be absurdly difficult to model in the context of KSP.

Alright, I'll rework my entire post into something completely different; micro-thrust engines.

Engines with less than 2 kN, allowing for extremely precise maneuvers

[Bej Kerman]

5 hours ago, intelliCom said:

Alright, I'll rework my entire post into something completely different; micro-thrust engines.

Engines with less than 2 kN, allowing for extremely precise maneuvers

What use do micro-thrust engines serve that you can't do just by using thrust limiter or making corrections later into the trajectory?

[daninplainsight]

6 hours ago, intelliCom said:

Alright, I'll rework my entire post into something completely different; micro-thrust engines.

Engines with less than 2 kN, allowing for extremely precise maneuvers

In the original KSP RCS thrusters or the Dawn engine currently fill that niche. I imagine that they won't leave that thrust class unrepresented in the sequel ¯\_ (ツ)_/¯

[intelliCom]

Well, sorry for making a post that bombed. I was going to ask about solar pressure affecting a spacecraft's trajectory, but I suspected it would be more of the same; not enough influence to be significant.

[Bej Kerman]

5 minutes ago, intelliCom said:

Well, sorry for making a post that bombed. I was going to ask about solar pressure affecting a spacecraft's trajectory, but I suspected it would be more of the same; not enough influence to be significant.

Ironically, that's a suggestion that makes sense. It'd allow solar sails which would make a good early-game alternative to ion engines.

[intelliCom]

22 minutes ago, Bej Kerman said:

Ironically, that's a suggestion that makes sense. It'd allow solar sails which would make a good early-game alternative to ion engines.

So we come full circle. Make a post about electromagnetic radiation pressure that's useless, only to suggest a different type of radiation pressure that works.

Could solar sails be partial? (I.e., Could a conventional chemical spacecraft (let's say the Apollo CSM) utilise solar sails as well, regardless of how heavy?)

Edited August 24, 2022 by intelliCom

[Bej Kerman]

11 minutes ago, intelliCom said:

Could solar sails be partial? (I.e., Could a conventional chemical spacecraft (let's say the Apollo CSM) utilise solar sails as well, regardless of how heavy?)

I think you're overestimating how much pressure there is in radiation pressure.

[t_v]

21 minutes ago, intelliCom said:

Could solar sails be partial? (I.e., Could a conventional chemical spacecraft (let's say the Apollo CSM) utilise solar sails as well, regardless of how heavy?)

This would give a pretty small amount of thrust unless the solar sails were ridiculously large (making it useless as a chemical rocket) and even then it would take a long time. Over the course of a ten-year mission, you could conceivably gain a few weeks using smaller solar sails, but I would rather fill up that mass with food and air that could last for a few months. 

[intelliCom]

46 minutes ago, t_v said:

This would give a pretty small amount of thrust unless the solar sails were ridiculously large (making it useless as a chemical rocket) and even then it would take a long time. Over the course of a ten-year mission, you could conceivably gain a few weeks using smaller solar sails, but I would rather fill up that mass with food and air that could last for a few months. 

Fair enough. Solar sails are for light-weight, unmanned spacecraft. Unless laser stations are involved to push the probe to a sizable portion of the speed of light for an interstellar probe.

[JadeOfMaar]

32 minutes ago, intelliCom said:

laser stations

Beamed power and laser sails are the best application of sail tech for KSP2. Playability needs to be considered before realism. An engine that realistically produces practically no thrust is going to be useless to the great majority of players who:

• Don't deal in the Realism Overhaul suite
• Might not even ever leave Kerbin's SOI
• Will spam many ion engines into their stock grand tour ship
• Are itching for MetallicHydrogen or the Daedalus

Semi-related: Lightcraft launch vehicles.