How to Spot NASA's Solar Sail Demonstration Streaking Through the Night Sky
smithsonianmag.com
smithsonianmag.com
Set your location in the upper-right corner, then select the ACS3 on the main page.
> From above, the sail will appear as a square, with an area of approximately 860 square feet (80 square meters) – about half the size of a tennis court.
Not bad for a device the size of a microwave...
I've always heard these as mentioned in the context of very long distance trips (heading away from the sun). But if you're orbiting the earth, how do you take advantage of this? In general, how do you use a solar sail to do anything other than head away from the sun?
When in orbit around earth, thrust in the direction of your orbit (prograde) causes you to gain energy and altitude, and retrograde thrust does the opposite.
[1] The "Solar Sail" wikipedia page says 800m x 800m is about 5N. This is 80m^2.
[2] https://ntrs.nasa.gov/api/citations/20210017923/downloads/Sm...
However, it strikes me as difficult to use this the deeper into space we go. I would assume the further from the sun you go, the less thrust you receive from the sail. Also, how do you slow down and stop? Maybe you don't...
I'm not a sailor, but doesn't this rely on the force of water on the keel, to avoid being pushed laterally?
> When in orbit around earth, thrust in the direction of your orbit (prograde) causes you to gain energy and altitude, and retrograde thrust does the opposite.
For station-keeping purposes, when should you prefer a solar sail as versus PV panels and an ion drive?
The analogy with sailing is actually kind of weak.
Since you get elastic collisions with photons on the sail, you can (approach) applying force at 90 degrees from the direction of the light. Unlike with actual sailing, you can never have an "upwind" force component.
I can't be bothered to draw a diagram, but imagine that the sun is to the "north", and the solar sail is at a 45-degree angle running NE/SW. Incoming photons heading south reflect off the sail and leave to the west. So the photons experience a net momentum change to the NW, pushing the sail to the SE, which is not directly away from the sun.
Anyone have a link to actual pictures of the probe?
Also -- what's happening to science when more and more articles seem to have CGI artists renditions instead of pictures of the real thing. I get that those with ADHD need some stimulation to keep them interested in science funding -- but as a skeptic I find the boring "real" photos far more interesting. It's getting harder to tell real programs from fictional programs with clickbait titles and pretty graphics i.e. "NASA has designs for a working warp drive"
/rant
edit: OK so I finally found an image of the final assembled satellite prior to launch here [0]
[0] https://pbs.twimg.com/media/GL2pPKZW4AAXK1P?format=jpg&name=...
That's the completed sattelite in the second link. The 'solid' booms are very similar to how a tape measure rolls out and remains rigid. Solar spacecraft are half sail by mass and half sattelite.
That said, I can think of a few reasons for not releasing a photo:
1. Solar sails are flimsily and fragile. The photo would likely not be representative of the craft in action.
2. The labs building these things may not have a professional photographer available.
3. A prototype craft might just look like junk. Wouldn’t be surprised if they want to iterate on the design a bit before they solidify the public’s vision of what a solar sailing craft looks like.
Apologies -- I was mainly referring to the "overstimulated generation" of kids and their effect on media becoming more clickbaity with fancy/fake images. It was a poor choice of mine to summarize this idea using the word ADHD.
...Is this a real concern of yours? I've never experienced such ambiguity
I'm sorry for joining the pile-on but why do you believe this is "new"? Artists interpretations and renderings have been the norm for space media since before NASA. It makes sense, since it's so hard to get the film crew out to Jupiter, and the craft all folded up on it's launch platform is usually less interesting to normal people than seeing the instrument as it will be in space
>but as a skeptic... It's getting harder to tell real programs... working warp drive
Skeptic? I promise you that everything put onto a rocket is real. Keep in mind that every single project anyone has ever had to get funding for will inevitably have a CGI rendering or artists interpretation because you need something to put on the first powerpoint slide when you pitch it to the funding board. This is not limited to NASA
In case you weren't aware, pretty much everything in advertising in a render as well. If the car is not moving in a commercial shot from a camera car/drone, it's more than likely 3D rendered. Those close up interior shots or the camera zooming from outside to the interior, yup, those are 3D rendered. A large portion of product shots (like furniture) online are 3D rendered as well. This has been happening for a long time too