Removing the brown ones from a bowl of M&Ms is a 5 minute job that can be handled by anyone. I would expect a lot of people would go "well that's a bit eccentric, but if it makes the band happy, why not".
I doubt the band would say "you didn't redline this weird but inconsequential request, we can't work together.
If they wanted to be sure the redlining process worked, they should have put in something like "remove all fire extinguishers from backstage".
> To use a dog metaphor, a chainsaw tends to growl before it bites.
I believe the author is mistaken about why chainsaws don't cause more harm than they do. There are multiple of ways in which a chainsaw will kill or destroy, without any warning. Kickback is very quick. A tree falling in the wrong direction comes without warning.
Personally, I suspect there are 2 main reasons why chainsaws don't cause more harm.
A) They've been around for 100 years, and they've been causing fatalities and injuries for 100 years. People have invented ways to reduce the risk. Any chain you can readily buy is a low-kickback chain, and the saw comes with a chain brake. It doesn't completely remove the risk, but it substantially reduces it.
B) They've been around for 100 years, and they've been causing fatalities and injuries for 100 years. People are aware that chainsaws are inherently dangerous. Even someone without any training, and without looking at the safety instructions, understands that one of these will take off a limb without blinking.
What this means for the rest of the metaphor, I'm not sure.
This is why I need to have 10 different map apps on my phone. I hate it.
Google maps is good enough for find my way in a city, or getting to a destination by car. And when I get there, I whip out another app to pay the parking. If I forget where I parked, my car has an app with a map. To plan a longer trip with an electric car, ABRP is better. And when I'm just looking for a charge pole where my card will work, Plugsurfing. If I want to use car sharing, another app with another map.
If I want to go for a run or a hike, outdooractive has some routes. Komoot has some others. But if I want to find some rock climbing routes, I need 27crags. Meanwhile, my sports watch also has a map which can show me the route I just ran.
None of these are fundamentally different. All show a very similar map, just with other points of interest, other routes, other layers, other navigation algorithms.
But all of these apps have different UI, different features, and just behave slightly differently.
I wish I could just have a single map app, where I enable the layers I'm interested in.
I feel like if you had all the map apps in one, you'd end up with a Salesforce of maps.
I kind of like having separate apps for different activities. For sure, it's nice that they integrate eg. gas station search into Waze -- it's a car-related thing, and a likely option in the workflow of navigating a trip. I'll use a totally different app for route finding along mountain trails - here I'll be concerned about offline availability, topography data, terrain types, shelters, precise location and orientation, etc.
To OP's point, it would be nice to have a bike-centric app that responds to concerns cyclists have and others pay little attention to - eg, road surface quality, lane widths, grading, wind exposure, general safety rating etc. Google Maps does the token thing of indicating the total climb and descent for a planned route, but it doesn't give an option to optimize for that (eg, longer route with fewer climbs).
Linux's `make menuconfig` [0] and GDB's TUI interface [1] are the first ones that come to mind. Both are very powerful once you get to know them a bit, and are still valuable tools today.
I find menuconfig to be a not-very-great TUI (too much stuff per page for my taste), but the GDB tui is really nice/functional (tho also idiosyncratic).
From the article, Proba-3 has 10 thrusters, so that would bring the total to 150 Watt.
I don't know the power budget for the satellite, but we can make an educated guess : the occulter is 1.4 meter diameter, or a surface area of 1.54 square meter. That's an upper bound for the surface area of the solar panels - there's nothing sticking out beyond the disk, that would interfere with observations.
Solar power at earth is about 1.3kW/sqm, solar panels are maybe 20% to 30% efficient. That puts you in the ballpark of 400 to 600W.
150W on standby would be a pretty big bite out of your power budget.
Many observations of the sun's corona just use a disk attached to the telescope, as you're suggesting [0]. However, for Proba-3 they want the disk to be over 100m away from the telescope, which isn't practical. Also, one of the goals of Proba-3 is to develop formation flying technology, because it will be useful for many other missions in the future.
The goal is to have them a bit more than 100m apart. During observations they aim to maintain millimeter precision.
I'm pretty sure the risk of collision has been analysed to death. I would expect they've analysed what would happen if one or both devices suddenly stop listening to commands, and that even then there's essentially no risk.
From what I can see on wikipedia [0] the first FEEP to be used in space was in 2018. Proba-3's implementation phase started in 2014 [1]. The choice of thruster technology was probably made well before that. They wouldn't use a technology that hasn't flown yet, unless it was crucial for the mission.
I understand that part of the objective is to demonstrate precise autonomous navigation and choreography, but for the "main" scientific objective re. observing the solar corona, why not just stick a big stick with a disk on the observing satellite?
That's what's been done so far [0], both on the ground and in space. As I understand it, the further your disk is from your telescope, the better. But your stick needs to be rigid enough to keep the disk exactly in its place. And a rigid stick has weight.
For Proba-3 the goal is to have the two satellites more than 100m apart. If you want to do that with a stick, your stick has to be longer than the ISS. That should tell you a thing or two about the complexity and cost of building and launching that stick.
I do have to admit I'm not exactly sure what the advantages are of having the disk further away from the telescope. I suspect it's to do with the interaction between the light and the edge of the disk, but I'm not sure.
The even more extreme version of this JPL has been working on with their Starshade program. Not specifically a cornograph, but same concept of blocking light from a star to look for something more dim, in this case its looking for exoplanets. But it is a much larger scale. A 25 m deployable shade in formation 100 km away with the same level of mm precision.
Edit: Just to be clear on status of this, Starshade is still in early technology demonstration phase that they can actually build the shade and do the formation maintenance. This is not in full build or slated to launch any time soon.
Huh, very interesting- and counterintuitive that distance matters. If anyone here knows why I’d love to learn more!!
EDIT: maybe not so counterintuitive after all: if you scale everything up, you get a higher fidelity sensor and more signal to noise. Same reason telescopes want to be big: to collect more light especially from dim signals. Distance of the occulter then reduces perspective distortion that would eclipse the inner parts of the sensor more than the outer ones. Just my speculation though.
I'm speculating past my understanding here, but wouldn't some sort of diffractive effect around the edge of the disk explain it? Like the further you are into the far field of that diffraction the better or such?
I worked on Proba-3 for a while. The original goal of the project was to demonstrate formation flying in preparation for another telescope (I forgot the name, but it was something like Xeus). That telescope would have a camera and lens on seperate spacecraft, and the idea was that by moving the lens backwards or forwards you'd be able to create a much bigger telescope than could be built with a single spacecraft. Unfortunately that telescope was cancelled, so although Proba-3 is still demonstrating a cool technology, it probably won't be applied elsewhere for a while.
I'm not familiar enough with the project to answer why specifically cold gas thrusters were chosen. What I can say : if old, proven technology will get the job done, there's a strong preference to use that.
When needed to achieve the mission, new technology will be developed - sometimes the whole point of a mission is specifically to develop new technology. In this case, one of the major goals of the mission is to develop formation flying technology. Learn what the pitfalls and the tricky bits are, and make the technology available for future missions.
But when the mission can be achieved with old technology - technology with a long record of being used in space, where the problems are known and understood, where we know what works and what causes problems - then the mission will use old technology.
If you use newer technology, there's always a risk that you'll hit a new issue, previously unknown. Maybe you can work around it, maybe you can't. But this isn't web development where you can refactor, switch to a new framework and continuous deploy your way out of it. For the hardware, you get one launch and that's it. Why run the risk if you can avoid it?
It'd be a shame if the mission can't achieve its primary objective (learning about formation flying) because it chose some new type of thruster, and encountered some new issue with it.
Cold gas thrusters are as reliable (because of simplicity - basically just container of pressurised gas and a valve [1]) and as precise in their thrust pulses execution as it can get. Better precision in thrust execution probably only ion engines have but just because of extremely low thrust levels in general (milli-newtons).
I saw a really good YT video a few months ago that explained this very well. Went over all the fuel types and tanks and propulsion designs.
Started with what you said - a simple gas pressurized and a single valve.
Slowly more and more was added until we get to current rocket designs with multiple stages or active pressurization / fuel transfer and all that entails.
They need the milli-newton level of thrust control and so need tiny thrusters. Generally the simplicity of the cold gas thrusters in a small package is easy. Yes it is not as efficient, but moving up in efficiency and complexity to catalyzed monopropellant (generally hydrazine) thrusters the thrust ranges are usually > 1N. Same story with any bi-prop thrusters. Certainly electric propulsion has the levels of thrust needed, but then you would need a lot of power for it. And since they are not doing large delta V maneuvers there is less concern about the actual amount of propellant that you need to take with you.
I would expect James Webb has the same issue, and similar ways of dealing with it. It's just that it never hits the press, since it's a normal part of operations.
I'm not sure why Euclid's icing issue is getting some attention now, from the ESA article this was expected. Maybe it's just that it's slightly worse than anticipated, and they're changing their way of dealing with it?
I doubt the band would say "you didn't redline this weird but inconsequential request, we can't work together.
If they wanted to be sure the redlining process worked, they should have put in something like "remove all fire extinguishers from backstage".