In 1887 Boys published this very entertaining article on how he produced long fine wires of quartz, by heating a small thread of glass (and other materials) with a blowpipe, such that it beads, the rod of glass was attached to a tiny dart on a crossbow beforehand, with a foot pedal to release the dart. When he released the dart right when the molten ball formed, the dart would shoot all through the hallway and 2 rooms before meeting a wall. The dart would stick in the wall and a continuous thread was formed between the crossbow and the dart on the end wall (about 90 feet or 30 meters away). When he switched to quartz he immediately observed that quartz took a much larger force, and hence decelerated the dart, so it wouldn't reach the other wall.
I wonder if quartz could be used for matching up Delta v for intercept missions.
Either way the first such probe should be called spiderman...
I cannot do justice for the style and presentation of this article, so you should read it for yourself:
He wrote the paper too :) Anyhow, I wonder if you can make a useful probe in the payload of a few grams? Maybe a swarm of them could act in concert to do useful things?
youtube's recommendation algorithm favours channels with a consistently scheduled upload cadence, high clickthru rate and spread/virality (people share the video - which is tracked by this si parameter in the share link if you use the share feature).
Science and education channels upload quite infrequently and irregularly (but each video is very high quality), but even if it is shared, it "drops off" as people finish watching it and move on.
And unfortunately, this sort of content just does not beat those clickbait slop that tends to get shared. I try to correct it often by sharing these videos myself, but alas i dont think my drop in the bucket makes much difference.
I don’t have much to offer the conversation other than a linguistic alternative.
TAURUS: Torqued Accelerator Using Radiation Unleashed from the Sun.
Grammatically correct and it doesn’t drop a word just to mimic a sci-fi robot’s name in an incredibly awkward and stilted way. I like Interstellar as much as the next person, but that acronym felt like a stretch, and it leaves out (literally) useful information.
I think the idea is very interesting, but please correct me if I’m wrong, isn’t the payload experiencing a sustained acceleration of hundreds of thousands of Gs, if not millions?
I am not sure that anything useful could survive that kind of sustained crushing acceleration. By comparison a rifle bullet being shot is around 100k Gs for millisecond , this would go on for weeks or months.
Given how short the proposal's tethers are, I'd suggest one can very easily reduce the peak G-force for any given linear speed by making the tethers longer. Once they get to the physical extremes (especially the bit at the end about enhancing tensile strength with an electric charge, which I suspect will involve surface voltages sufficient for pair production from any stray electrons accelerated from one to the other*), it stops being easy.
It's SpinLaunch from solar orbit rather than the surface of the Earth (in fact, they themselves say so at the end of 11.1). Even for the current tech demo of SpinLaunch, that was getting 10k G and the company found it wasn't too difficult to make payloads survive that: https://www.youtube.com/watch?v=g-DjBHroA1I
Yes, that's 10x-100x less than what you're asking (I've only skim-read the paper, your 100k-1M is certainly plausible given what they're focusing on is the "can it be done at all" and not a detailed launch proposal), but in practice if we were limited to 10k (we're probably not) that only means making the tether 10x-100x the length in this paper.
* My citation here is just "gut feeling" as I play around with ideas like this from time to time, and this particular thing, using electric forces for a non-gravitational orbit, was something I came up with and then rejected on this basis as part a hard-science tractor beam in the novel I've still not finished writing, and the accidental antimatter problem happened with relatively small accelerations for a plausible mass probe.
You can certainly make the tethers longer, but that re-introduces other problems with the tensile strength that the current proposed shape is intended to mitigate.
I’m very skeptical about Spinlaunch, but even if you can pour enough epoxy over something to allow it to survive 10k Gs for a few minutes, I am not sure you can scale it to 100k+ Gs for weeks, for a postage stamp sized payload that has to be almost perfectly flat - that just seems like a completely different problem domain.
I think the idea bears further investigation, but the omission from the paper feels a bit odd.
> I’m very skeptical about Spinlaunch, but even if you can pour enough epoxy over something to allow it to survive 10k Gs for a few minutes,
Please do watch the video I linked to — it was a surprise to the people whose cubesat design they lightly modified, that they didn't need to fill all voids with epoxy resin.
> I am not sure you can scale it to 100k+ Gs for weeks, for a postage stamp sized payload that has to be almost perfectly flat - that just seems like a completely different problem domain.
If anything, I expect "flat postage stamp" to be easier, even with a 100x increase in G-forces. Thin structure in compression -> total forces are still low. Balancing a fully laden lorry on a 10cm cube of steel (7.5kg vs 50 tons ~= 6,000x) seems borderline in the way that balancing a 10cm cube of steel on top of 1cm^2 of 80 gsm paper (=8mg vs 7.5kg ~= 937500) doesn't.
(Edit: forgot density of steel, thought it was 5 not 7.5)
> I think the idea bears further investigation, but the omission from the paper feels a bit odd.
100%. It does feel a bit like it's formalising my shower thoughts.
Ah, but that’s the thing it’s not compression it’s tension. Try hanging the same steel cube from the ceiling with a scrap of paper and things get decidedly more difficult.
And even if you can find some magic superglue left in the tube to hold it there, it has to hang there for weeks: A cubist sword of Damocles.
The tether is always in tension, in general the payload is allowed to be in either tension (if attached to the tether on the "top") or compression (if in a pouch of the same material as the tether, e.g. shepherd's sling configuration: https://en.wikipedia.org/wiki/Sling_(weapon)), at the preference of the system designer.
It’s a good point: I’d assumed that the plan was to make the payload of basically the same material as the tether/structure, and have it destructively tear-off at the right moment (maybe by having a watching supervisor structure lasering a weak point)
But I think pouching the payload (presumably forming the structure around the payload) just translates the problem into holding a 8kg steel block to the ceiling with 1cm square of paper formed into a harness, and expecting it to hold for weeks.
Either way - hopefully it will be addressed in a follow-up
The white paper says the payload release doesn't have to be precisely timed, if TARS is on a circular orbit, and I do not understand why. Sure, the plane in which the payload shoots off, is defined by the orbital position of TARS. But there are 360 degrees of freedom within that plane. If we aim at e.g. a specific star, how is release timing not a critical factor? And if it is, what timer would survive the solar radiation and extreme spinning, remaining reliably operational and microsecond accurate?
> In the case where TARS is on a circular orbit, the moment of release need not be precisely when v = v_targ, but rather can be at a specific orbital phase position instead.
My understanding is that it means it does not have to be precisely timed with regard to velocity, but has to be with regard to angle.
The timer would not need to be onboard the spinning flywheel, it could be on an observing quasite orbiting higher. When it's time to launch it could shine a control laser at the flywheel, which is used to time the triggering of a cutting laser at the right position to slice the payload off at the correct angle.
One timer could be used to launch multiple flywheel payloads over time
I wonder if quartz fibers can be used.
In 1887 Boys published this very entertaining article on how he produced long fine wires of quartz, by heating a small thread of glass (and other materials) with a blowpipe, such that it beads, the rod of glass was attached to a tiny dart on a crossbow beforehand, with a foot pedal to release the dart. When he released the dart right when the molten ball formed, the dart would shoot all through the hallway and 2 rooms before meeting a wall. The dart would stick in the wall and a continuous thread was formed between the crossbow and the dart on the end wall (about 90 feet or 30 meters away). When he switched to quartz he immediately observed that quartz took a much larger force, and hence decelerated the dart, so it wouldn't reach the other wall.
I wonder if quartz could be used for matching up Delta v for intercept missions.
Either way the first such probe should be called spiderman...
I cannot do justice for the style and presentation of this article, so you should read it for yourself:
https://zenodo.org/records/1431517/files/article.pdf
David Kipping of Cool Worlds Lab just uploaded a video about TARS:
https://www.youtube.com/watch?v=MDM1COWJ2Hc
He wrote the paper too :) Anyhow, I wonder if you can make a useful probe in the payload of a few grams? Maybe a swarm of them could act in concert to do useful things?
This is amazing. How have i never seen this channel before?
He’s an incredible scientist and educator. His back catalog of videos is well worth watching.
youtube's recommendation algorithm favours channels with a consistently scheduled upload cadence, high clickthru rate and spread/virality (people share the video - which is tracked by this si parameter in the share link if you use the share feature).
Science and education channels upload quite infrequently and irregularly (but each video is very high quality), but even if it is shared, it "drops off" as people finish watching it and move on.
And unfortunately, this sort of content just does not beat those clickbait slop that tends to get shared. I try to correct it often by sharing these videos myself, but alas i dont think my drop in the bucket makes much difference.
I don’t have much to offer the conversation other than a linguistic alternative.
TAURUS: Torqued Accelerator Using Radiation Unleashed from the Sun.
Grammatically correct and it doesn’t drop a word just to mimic a sci-fi robot’s name in an incredibly awkward and stilted way. I like Interstellar as much as the next person, but that acronym felt like a stretch, and it leaves out (literally) useful information.
I think the idea is very interesting, but please correct me if I’m wrong, isn’t the payload experiencing a sustained acceleration of hundreds of thousands of Gs, if not millions?
I am not sure that anything useful could survive that kind of sustained crushing acceleration. By comparison a rifle bullet being shot is around 100k Gs for millisecond , this would go on for weeks or months.
Given how short the proposal's tethers are, I'd suggest one can very easily reduce the peak G-force for any given linear speed by making the tethers longer. Once they get to the physical extremes (especially the bit at the end about enhancing tensile strength with an electric charge, which I suspect will involve surface voltages sufficient for pair production from any stray electrons accelerated from one to the other*), it stops being easy.
It's SpinLaunch from solar orbit rather than the surface of the Earth (in fact, they themselves say so at the end of 11.1). Even for the current tech demo of SpinLaunch, that was getting 10k G and the company found it wasn't too difficult to make payloads survive that: https://www.youtube.com/watch?v=g-DjBHroA1I
Yes, that's 10x-100x less than what you're asking (I've only skim-read the paper, your 100k-1M is certainly plausible given what they're focusing on is the "can it be done at all" and not a detailed launch proposal), but in practice if we were limited to 10k (we're probably not) that only means making the tether 10x-100x the length in this paper.
* My citation here is just "gut feeling" as I play around with ideas like this from time to time, and this particular thing, using electric forces for a non-gravitational orbit, was something I came up with and then rejected on this basis as part a hard-science tractor beam in the novel I've still not finished writing, and the accidental antimatter problem happened with relatively small accelerations for a plausible mass probe.
You can certainly make the tethers longer, but that re-introduces other problems with the tensile strength that the current proposed shape is intended to mitigate.
I’m very skeptical about Spinlaunch, but even if you can pour enough epoxy over something to allow it to survive 10k Gs for a few minutes, I am not sure you can scale it to 100k+ Gs for weeks, for a postage stamp sized payload that has to be almost perfectly flat - that just seems like a completely different problem domain.
I think the idea bears further investigation, but the omission from the paper feels a bit odd.
Good luck with the novel!
> I’m very skeptical about Spinlaunch, but even if you can pour enough epoxy over something to allow it to survive 10k Gs for a few minutes,
Please do watch the video I linked to — it was a surprise to the people whose cubesat design they lightly modified, that they didn't need to fill all voids with epoxy resin.
> I am not sure you can scale it to 100k+ Gs for weeks, for a postage stamp sized payload that has to be almost perfectly flat - that just seems like a completely different problem domain.
If anything, I expect "flat postage stamp" to be easier, even with a 100x increase in G-forces. Thin structure in compression -> total forces are still low. Balancing a fully laden lorry on a 10cm cube of steel (7.5kg vs 50 tons ~= 6,000x) seems borderline in the way that balancing a 10cm cube of steel on top of 1cm^2 of 80 gsm paper (=8mg vs 7.5kg ~= 937500) doesn't.
(Edit: forgot density of steel, thought it was 5 not 7.5)
> I think the idea bears further investigation, but the omission from the paper feels a bit odd.
100%. It does feel a bit like it's formalising my shower thoughts.
> Good luck with the novel!
Thanks, I'll need it! >_>
Ah, but that’s the thing it’s not compression it’s tension. Try hanging the same steel cube from the ceiling with a scrap of paper and things get decidedly more difficult.
And even if you can find some magic superglue left in the tube to hold it there, it has to hang there for weeks: A cubist sword of Damocles.
The tether is always in tension, in general the payload is allowed to be in either tension (if attached to the tether on the "top") or compression (if in a pouch of the same material as the tether, e.g. shepherd's sling configuration: https://en.wikipedia.org/wiki/Sling_(weapon)), at the preference of the system designer.
It’s a good point: I’d assumed that the plan was to make the payload of basically the same material as the tether/structure, and have it destructively tear-off at the right moment (maybe by having a watching supervisor structure lasering a weak point)
But I think pouching the payload (presumably forming the structure around the payload) just translates the problem into holding a 8kg steel block to the ceiling with 1cm square of paper formed into a harness, and expecting it to hold for weeks.
Either way - hopefully it will be addressed in a follow-up
The white paper says the payload release doesn't have to be precisely timed, if TARS is on a circular orbit, and I do not understand why. Sure, the plane in which the payload shoots off, is defined by the orbital position of TARS. But there are 360 degrees of freedom within that plane. If we aim at e.g. a specific star, how is release timing not a critical factor? And if it is, what timer would survive the solar radiation and extreme spinning, remaining reliably operational and microsecond accurate?
Are you talking about this?
> In the case where TARS is on a circular orbit, the moment of release need not be precisely when v = v_targ, but rather can be at a specific orbital phase position instead.
My understanding is that it means it does not have to be precisely timed with regard to velocity, but has to be with regard to angle.
The timer would not need to be onboard the spinning flywheel, it could be on an observing quasite orbiting higher. When it's time to launch it could shine a control laser at the flywheel, which is used to time the triggering of a cutting laser at the right position to slice the payload off at the correct angle.
One timer could be used to launch multiple flywheel payloads over time