6 ms·

Different missions require vastly different hardware. > Orbit around, Orbiting Europa requires a different amount of propellant than orbiting Mars. Solar pane

by avian 11y ago

Different missions require vastly different hardware. > Orbit around, Orbiting Europa requires a different amount of propellant than orbiting Mars. Solar panels that power a probe at Mars won't power one farther away from the sun. Radio that can talk with Earth from the Mars orbit won't be able to do that from Jupiter. > take photos and Different cameras required due to different amount of light, expected distances for imaging, filters optimized for materials being imaged, etc. > readings. What readings? Basically no two probes carry the same set of scientific instruments. Often, the instruments carried are one-of-a-kind, specifically designed for the specific thing the mission wants to investigate.

anigbrowl 11y ago
Basically no two probes carry the same set of scientific instruments. That's the problem. Great as those are, by continually making one- or two-of-a-kind devices we are endlessly prototyping. What if we picked one or a few different designs, selecting for greatest generality, and then worked to get the costs very low by manufacturing a lot of them, accepting that they will be suboptimal for almost every target? Of course crappy probes would give crappy results, and many of them would fail altogether. But what if we deployed hundreds of cheap crappy probes on a regular basis - ie build a shotgun instead of a series of sniper rifles? Obviously finding a good general-purpose design is easier said than done. We have I think 3 lunar probes in orbit at the moment, and a few more on the way, as well as various probes that have gone to the moon, sent back a bit of data, and then crashed into it by design. That's not very many at all. The moon's not that far away, why not try putting 50 low-cost probes around it with the same instrumentation and see what we learn from that? If we can get better astronomical observations from arrays of relatively low-power telescopes, surely we will get better planetary observational data from arrays of low-quality probes? Simply getting an array of probes up there and running and learning hwo to handle the networking, data flow, and and the inevitable variety of unexpected failure modes will provide us with a vast amount of experience, not to mention a vast amount of additional data about the moon that can be benchmarked against a whole lot of excellent data we have already for accuracy. I don't mean this as a dig at you or the other commenters critiquing this proposal, but you remind me of Thomas J Watson suggesting that "I think there is a world market for maybe five computers" (not withstanding the apocryphal nature of this quote, similar sentiments were expressed by other experts around that period, eg https://en.wikipedia.org/wiki/Thomas_J._Watson#Famous_misquote https://en.wikipedia.org/wiki/Thomas_J._Watson#Famous_misquo...).
- srdev 11y ago
  You're ignoring the lifting costs. The cost of lifting a payload into space and putting it into orbit is non-trivial compared to the cost of developing the probe. Can you imagine the cost of trying to put 50 probes into Julian orbit? Or even Lunar orbit? It would be cost-prohibitive. It gets worse if you use a bunch of mass-produced designs because you'd have a bunch of instruments of marginal value to the mission increasing lifting costs. I also think you're assuming its possible to reduce to a general set of equipment that can answer the scientific questions that we're trying to answer. If you consider, for example, the difference between the things that Philae, Curiosity, New Horizons, Dawn, and this Europa probe are testing and the conditions that they are testing them in, then its hard to arrive at a common design that can handle all these conditions. Edit: Another thing to consider is launch windows. You typically don't want to just regularly launch stuff to put near Mars or Jupiter whenever. You time your launches such that you can get them there within a certain amount of dV budget, otherwise you're dramatically increasing your deployment costs. This means that you only have a short window in which you can send out your shotgun probes -- you can't send them out constantly even if the lifting costs were feasible.
  - anigbrowl 11y ago
    Let's focus on the lunar orbit idea as a relatively straightforward objective, since it is practically in our backyard and we have so much experience there. I am not suggesting we perform 50 different launches into space. That would be hopelessly wasteful. But suppose we did one launch, sent one ship towards the moon, and then have it release 50 probes as it got close, each with a small amount of propellant sufficient get itself into orbit. I am not suggesting a common design that is adequate to handle all the different conditions of the different missions you mention. I said specifically that we should focus some effort on developing cheap probes, accepting that they will be suboptimal in almost every case. Let's consider one of the most basic things we like to do, which is to simply take pictures of things. Pictures help sell science to the public because most people are interested in how things look, and they are scientifically useful. When we aggregate multiple pictures of the same subject we often get even more useful scientific data. Downsides, the data transmission requirements are large and visual spectrum is just a small slice of the information we'd like to collect. Upsides, you can buy a COTS camera that takes 4k video or ~50mp stills for a few thousand $. Likewise you can buy a fast lens of high optical quality very cheaply, and record onto very cheap solid-state media. Let's accept that it will fail in some situations and that we don't expect it to keep working for ever, but we would like it to work for a while. so we need some power (onboard or renewable or some combination of the two), an antenna of some sort to transmit the data back and listen to requests from our end, some shielding to protect it against the slings and arrows of outrageous fortune, some sort of propulsion to get it into position and point it roughly where we want it to look, and a little control system to run it all. Technologically this is no longer a tall order. We can stick a consumer video camera & phone in a lunchbox, attach it to a balloon, send it up to the stratosphere, and retrieve it afterwards for only hundreds of dollars, it's a middle-school project by now. I think that we could make a pretty decent camera probe that would take relatively high resolution pictures at a relatively low frame rate and last for at least a year for a marginal cost of $100,000, maybe quite a bit less. 50 of those would be $5 million, which is the sort of sum you can raise on Kickstarter. Now, the fixed costs of launch, building a deployment module and numerous other things would be a lot higher, let's say they started at $50 million. Well, that's quite a lot of money but you could still raise it pretty easily. Donald Trump plans to waste twice that amount on promoting himself as a public figure while pretending he wants to be President, a summer blockbuster movie has launch costs of about $200m including marketing. There are lots of people in Silicon Valley who could write checks for that whole amount if they really wanted to. I pick $50 million as a benchmark because India managed to get a probe going around Mars for ~$75 million, so I don't think it's a totally outrageous idea to think we could deploy a bunch of lunar microsatellites for 2/3 of that. OK, let's say we even went overbudget by a factor 2 but we managed to do it. We have 50 probes in lunar orbit sending back, i dunno, 43 4k photographs of the lunar surface at the rate of 1 frame/minute (7 of them failed to deploy properly). None of them works properly for longer than 18 months. Within a few years they have all fallen out of orbit and are space junk on the lunar surface. Well, I think that we'd get a ton of useful knowledge from doing that.
Patrick_Devine 11y ago
Your statement about missions requiring different types of hardware isn't wrong, but having a generic platform for creating probes with different mission profiles isn't a bad idea. Think of it like a car platform which enables you to put on different bodies, interiors, etc. to suit the tastes and requirements of purchaser. If you had a standardized parts bin you could select whatever you needed to meet your mission objectives. That said, usually you would do this to leverage economies of scale, and I think there probably isn't the budget or demand for enough space probes to make it viable. Who knows though, if the price of space launches continues to plummet, maybe it starts to make a lot of sense.
stephengillie 11y ago
> Basically no two probes carry the same set of scientific instruments. Often, the instruments carried are one-of-a-kind, specifically designed for the specific thing the mission wants to investigate. Whatever these things are, I'm assuming 3 facts: 1. They require some type of electricity to operate. 2. They require a data interface for output. 3. They occupy a finite amount of space. Based on these, can't we modularize the scientific instruments? Provide common power and data ports within a common frame? So they can fit into the same bays, like a blade server, or even like Hubble's 4 bays.
- planteen 11y ago
  Your assumptions are correct. And this is how the spacecraft industry operates. In fact, like rack units, CubeSats have "1U", "3U", etc. Spacecraft components and instruments are modular. Data interfaces vary, but 1553, SpaceWire, and RS-422 UART are all quite popular. The part that all the instruments and components bolt to are called the bus. Aerospace companies have standard buses. The huge variable is the mission itself. Your blade server analogy is too narrow. Look at applications of computers on the ground. If you want to put a computer on a collar to track wolves, a blade server doesn't work. If you want a computer to take with you on a jog, a smartphone is appropriate. If you want to run a data center, a blade is great. Spacecraft vary just like this. JWST is the size of a tennis court. KickSat was the size of a cracker. The environments they operate in are crazy. The Voyagers are in deep space a light day away. Some spacecraft are just a few hundred kilometers over your head. A one-size fits all approach doesn't work.

by avian 11y ago

anigbrowl 11y ago

Basically no two probes carry the same set of scientific instruments. That's the problem. Great as those are, by continually making one- or two-of-a-kind devices we are endlessly prototyping. What if we picked one or a few different designs, selecting for greatest generality, and then worked to get the costs very low by manufacturing a lot of them, accepting that they will be suboptimal for almost every target? Of course crappy probes would give crappy results, and many of them would fail altogether. But what if we deployed hundreds of cheap crappy probes on a regular basis - ie build a shotgun instead of a series of sniper rifles? Obviously finding a good general-purpose design is easier said than done. We have I think 3 lunar probes in orbit at the moment, and a few more on the way, as well as various probes that have gone to the moon, sent back a bit of data, and then crashed into it by design. That's not very many at all. The moon's not that far away, why not try putting 50 low-cost probes around it with the same instrumentation and see what we learn from that? If we can get better astronomical observations from arrays of relatively low-power telescopes, surely we will get better planetary observational data from arrays of low-quality probes? Simply getting an array of probes up there and running and learning hwo to handle the networking, data flow, and and the inevitable variety of unexpected failure modes will provide us with a vast amount of experience, not to mention a vast amount of additional data about the moon that can be benchmarked against a whole lot of excellent data we have already for accuracy. I don't mean this as a dig at you or the other commenters critiquing this proposal, but you remind me of Thomas J Watson suggesting that "I think there is a world market for maybe five computers" (not withstanding the apocryphal nature of this quote, similar sentiments were expressed by other experts around that period, eg https://en.wikipedia.org/wiki/Thomas_J._Watson#Famous_misquote https://en.wikipedia.org/wiki/Thomas_J._Watson#Famous_misquo...).

srdev 11y ago
You're ignoring the lifting costs. The cost of lifting a payload into space and putting it into orbit is non-trivial compared to the cost of developing the probe. Can you imagine the cost of trying to put 50 probes into Julian orbit? Or even Lunar orbit? It would be cost-prohibitive. It gets worse if you use a bunch of mass-produced designs because you'd have a bunch of instruments of marginal value to the mission increasing lifting costs. I also think you're assuming its possible to reduce to a general set of equipment that can answer the scientific questions that we're trying to answer. If you consider, for example, the difference between the things that Philae, Curiosity, New Horizons, Dawn, and this Europa probe are testing and the conditions that they are testing them in, then its hard to arrive at a common design that can handle all these conditions. Edit: Another thing to consider is launch windows. You typically don't want to just regularly launch stuff to put near Mars or Jupiter whenever. You time your launches such that you can get them there within a certain amount of dV budget, otherwise you're dramatically increasing your deployment costs. This means that you only have a short window in which you can send out your shotgun probes -- you can't send them out constantly even if the lifting costs were feasible.
- anigbrowl 11y ago
  Let's focus on the lunar orbit idea as a relatively straightforward objective, since it is practically in our backyard and we have so much experience there. I am not suggesting we perform 50 different launches into space. That would be hopelessly wasteful. But suppose we did one launch, sent one ship towards the moon, and then have it release 50 probes as it got close, each with a small amount of propellant sufficient get itself into orbit. I am not suggesting a common design that is adequate to handle all the different conditions of the different missions you mention. I said specifically that we should focus some effort on developing cheap probes, accepting that they will be suboptimal in almost every case. Let's consider one of the most basic things we like to do, which is to simply take pictures of things. Pictures help sell science to the public because most people are interested in how things look, and they are scientifically useful. When we aggregate multiple pictures of the same subject we often get even more useful scientific data. Downsides, the data transmission requirements are large and visual spectrum is just a small slice of the information we'd like to collect. Upsides, you can buy a COTS camera that takes 4k video or ~50mp stills for a few thousand $. Likewise you can buy a fast lens of high optical quality very cheaply, and record onto very cheap solid-state media. Let's accept that it will fail in some situations and that we don't expect it to keep working for ever, but we would like it to work for a while. so we need some power (onboard or renewable or some combination of the two), an antenna of some sort to transmit the data back and listen to requests from our end, some shielding to protect it against the slings and arrows of outrageous fortune, some sort of propulsion to get it into position and point it roughly where we want it to look, and a little control system to run it all. Technologically this is no longer a tall order. We can stick a consumer video camera & phone in a lunchbox, attach it to a balloon, send it up to the stratosphere, and retrieve it afterwards for only hundreds of dollars, it's a middle-school project by now. I think that we could make a pretty decent camera probe that would take relatively high resolution pictures at a relatively low frame rate and last for at least a year for a marginal cost of $100,000, maybe quite a bit less. 50 of those would be $5 million, which is the sort of sum you can raise on Kickstarter. Now, the fixed costs of launch, building a deployment module and numerous other things would be a lot higher, let's say they started at $50 million. Well, that's quite a lot of money but you could still raise it pretty easily. Donald Trump plans to waste twice that amount on promoting himself as a public figure while pretending he wants to be President, a summer blockbuster movie has launch costs of about $200m including marketing. There are lots of people in Silicon Valley who could write checks for that whole amount if they really wanted to. I pick $50 million as a benchmark because India managed to get a probe going around Mars for ~$75 million, so I don't think it's a totally outrageous idea to think we could deploy a bunch of lunar microsatellites for 2/3 of that. OK, let's say we even went overbudget by a factor 2 but we managed to do it. We have 50 probes in lunar orbit sending back, i dunno, 43 4k photographs of the lunar surface at the rate of 1 frame/minute (7 of them failed to deploy properly). None of them works properly for longer than 18 months. Within a few years they have all fallen out of orbit and are space junk on the lunar surface. Well, I think that we'd get a ton of useful knowledge from doing that.

Patrick_Devine 11y ago

Your statement about missions requiring different types of hardware isn't wrong, but having a generic platform for creating probes with different mission profiles isn't a bad idea. Think of it like a car platform which enables you to put on different bodies, interiors, etc. to suit the tastes and requirements of purchaser. If you had a standardized parts bin you could select whatever you needed to meet your mission objectives. That said, usually you would do this to leverage economies of scale, and I think there probably isn't the budget or demand for enough space probes to make it viable. Who knows though, if the price of space launches continues to plummet, maybe it starts to make a lot of sense.

stephengillie 11y ago

> Basically no two probes carry the same set of scientific instruments. Often, the instruments carried are one-of-a-kind, specifically designed for the specific thing the mission wants to investigate. Whatever these things are, I'm assuming 3 facts: 1. They require some type of electricity to operate. 2. They require a data interface for output. 3. They occupy a finite amount of space. Based on these, can't we modularize the scientific instruments? Provide common power and data ports within a common frame? So they can fit into the same bays, like a blade server, or even like Hubble's 4 bays.

planteen 11y ago
Your assumptions are correct. And this is how the spacecraft industry operates. In fact, like rack units, CubeSats have "1U", "3U", etc. Spacecraft components and instruments are modular. Data interfaces vary, but 1553, SpaceWire, and RS-422 UART are all quite popular. The part that all the instruments and components bolt to are called the bus. Aerospace companies have standard buses. The huge variable is the mission itself. Your blade server analogy is too narrow. Look at applications of computers on the ground. If you want to put a computer on a collar to track wolves, a blade server doesn't work. If you want a computer to take with you on a jog, a smartphone is appropriate. If you want to run a data center, a blade is great. Spacecraft vary just like this. JWST is the size of a tennis court. KickSat was the size of a cracker. The environments they operate in are crazy. The Voyagers are in deep space a light day away. Some spacecraft are just a few hundred kilometers over your head. A one-size fits all approach doesn't work.