Or maybe the advantage is not having to counter any sail movement with gyroscopes… which cost energy too.

I think you nailed it right there.

Pass…

Well that’s a really interesting application though… 9 times less thrust may not actually be a very big deal. A solar sail probe would likely be a lot lighter than a fueled equivalent, so that means you have the payload mass to send more probes on the same launch. And asteroids don’t have meaningful amounts of gravity, so you can take as long as you want to get from one to another (you don’t need much thrust to overcome their gravity well). So yeah, I think more than likely you could make up for a lack of speed with sheer quantity.

That’s such a badass design, I love it.

A variable thrust and thrust vectoring propulsion system with no moving parts. I doubt that’s ever been done before…

Yeah, we may well end up seeing a lot more use of solar light pressure to orient spacecraft over the coming years, especially deep space probes and higher orbit satellites. Telecom satellites need a lot of power for their transmitters, so they generally have quite large solar arrays, I wouldn’t be surprised to see some of those using this method for station keeping. (Though these days they’re already using very efficient ion thrusters for station keeping, so they may not really need to use this method)

But while solar sail propulsion takes a lot of very specific design requirements, using solar pressure just for maintaining orientation doesn’t actually require any fancy hardware (if you already have solar panels), it’s all an entirely software solution. Which means it’s always a viable backup plan when hardware failures occur.

Well… I’m afraid I’m not sure if they’ll be effective for the ISS. The ISS sits in low orbit (a relatively high part of Leo, but none the less), so it hits some extremely thin atmosphere, which has a noticeable drag over time. For that reason the ISS has to boost its orbit a little every few months. My fear is that a solar sail large enough to have an effect on the ISS is probably large enough to add a whole lot of atmospheric drag, even from just the trace particles it encounters.

Maybe someone can answer me this: I’ve always wondered if a solar sail can only generate momentum away from the sun or if it can be angled to create momentum in other direction.

Yeah, 100%. You can totally steer and control your orientation with a solar sail. This is one of the rare actually intuitive things when it comes to spaceflight. (with physics in space It seems like nothing actually works the way you’d expect it to, but this basically does)

We actually have some experience controlling orientation with “solar sails” too. I remember one example of a spacecraft which long after finishing its official mission was left to tumble out of control. Years later, some engineers were able to regain control, use the last of its propellant to counter its tumble and then keep it oriented correctly using only its solar panels as sails, light pressure was carefully controlled to keep the spacecraft oriented.

I believe this is one of those things that benefits from scale. Theoretically, the larger you make the sail, the better the thrust to mass ratio you can achieve (even before calculating a better payload mass to sail mass ratio). With improved materials, we can make stronger and lighter sails and support structures, and this will in turn result in higher velocities by the time the vehicle has left the effective range of the sun. I think speeds truly approaching c are unlikely, but they can still achieve “really freaking fast”.

But then new advanced materials could also change that, we’re developing metamaterials with some fascinating properties, carbon nanotubes are just the tip of the iceberg. Who’s to say that we couldn’t some day achieve those speeds.

Doesn’t “solar wind” refer to the physical particles emitted from the sun? Like hydrogen, helium, etc ejected from the sun’s outer layers?

My understanding is that the solar sail is propelled mostly by the photons themselves, not the atomic particles that may also be reaching it.

Of course this probably doesn’t change your argument at all, since the intensity of light drops off precipitously as you fly further and further from the sun.

Ok, a side note on etiquette here.

When I saw this reply it had a point score of 0, which means somebody downvoted the post.

When a user is freely admitting a lack of expertise, and defers to another user who seems to know better, I would say it’s extremely rude to downvote that reply.

This is an example of a user going out of their way to humbly rescind their previous statements when it appears they were mistaken (this is admirable and not a thing that usually happens on the Internet). They didn’t do it for their own benefit, but for the benefit of the community, to not leave misleading or incorrect information in the comments.

So to sum up, downvoting a selfless act is pretty shitty and not good for the community.

Yeah, the hivemind can get pretty tiresome.

Are you joking? Well the answer is no, no the SLS is about 40 years behind as far as technology goes. It’s basically a shuttle derived launch vehicle, the boosters are similar to the shuttle side boosters and it uses 4 slightly updated RS-25s (the space shuttle main engines) in the center stage.

Except instead of getting with the times and attempting some reusability, it actually has less reusability than the shuttle had. They actually throw away all of those expensive high performance hydrolox engines on every launch.

That’s literally exactly what spaceX is developing, rockets you don’t have to blow up every flight.

Fully reusable rockets have never been done before, but they’re coming.

I fully support this. Fuck Uber.

Oh ok, well that’s a relief. I’m glad we had you and your crystal ball handy!

Haha everyone keeps saying that! But it’s pretty funny how wrong everyone is about where the mistake was.

The math is just fine, I did the simple addition correctly. It’s the reading comprehension that I got wrong, I misunderstood what the sentence was saying.

No, my math is just fine, it’s my reading comprehension that needs work, because I totally misunderstood what that sentence was saying.

Oh thank you, my mistake. Still the numbers are huge!

Ugh… it drives me nuts!

Musk had to borrow around $13 billion for his doomed $44 billion acquisition.

Had he spent that $57 $44 billion on developing space hardware instead of going insane and squandering it on social media bullshit, he might have done something worthwhile. I mean… fifty seven billion! What even is that much money? He could have had his own space station for that much money! He could fly up there for weekends, just for funzies.

My assumption would be that they’ll work better.

The scariest part of technology is software updates.