So why can't we bulk produce space probes?

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Ephemeron
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So why can't we bulk produce space probes?

Postby Ephemeron » Fri Jun 28, 2013 7:17 pm UTC

I've often wondered why space probes like Curiosity are usually only one of a kind. Nothing's stopping them from making the same design twice. After all, there are two Voyagers. So why not ten, or a hundred? Economy of scale and all that. Why can't we roll them off an assembly line, and probe-spam the entire solar system? Humanity's spacecraft production rate must have some kind of limiting factor that I'm not aware of, but what is it?

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Re: So why can't we bulk produce space probes?

Postby scarecrovv » Fri Jun 28, 2013 8:47 pm UTC

While mass production of the probes themselves may work to reduce costs significantly, launch costs are high, and cannot be reduced by more than a factor of 10 (being super-optimistic) without a huge infrastructural investment. So either we still have to build a rocket for every one of 100 probes (which congress doesn't want to do), or we have to build a space elevator, launch loop, laser launch facility, scram cannon, or other non-rocket spacelaunch facility, which congress doesn't want to pay for either. There's no way to do it cheaply unless you're willing to invest big-time up front.

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Re: So why can't we bulk produce space probes?

Postby thoughtfully » Fri Jun 28, 2013 10:18 pm UTC

That's pretty much it. The probe itself is a small portion of the total expense, and each mission is sufficiently distinct, that it just doesn't make sense to reuse the whole thing. Also, probes are often (not always) pushing the limits of space-ready technology, so there's an incentive to design something new. I kinda remember reading about components of projects being reused in later projects, which makes sense, but I don't have any references handy.

The economies of scale simply don't exist. It isn't hard to imagine applications for mass production of probes, but it is hard to imagine justifying the expense.
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Re: So why can't we bulk produce space probes?

Postby idobox » Sat Jun 29, 2013 12:01 am UTC

Also, what is the point of sending two Curiosity?
Identical probes have limited usefulness: redundancy and testing the same stuff somewhere else. Of course, a Mars rover is pretty much useless anywhere but on Mars, and I guess digging holes and shooting lasers in a second valley is not worth spending twice as much.
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Re: So why can't we bulk produce space probes?

Postby Ephemeron » Sat Jun 29, 2013 12:30 am UTC

Au Contraire. There is plenty of reasons to send probes to other locations. Mars is a big place. This is the very reason why Spirit and Opportunity took such long journeys over the surface of Mars, as it gave them a greater range of places to study. There will always be more of Mars to explore. And that's just Mars. The outer planets are just begging for exploration. It's almost criminal that Uranus and Neptune have only been visited once, by Voyager 2 in the '80s. And that's not even counting the moons. You could send a probe to every moon of a gas giant, and still be finding out new things about the solar system.

I've heard that some 'pico satellites' weigh less than a kilogram. I know it's not quite the same thing, as they are destined for low earth orbit. But couldn't the same principle be applied to interplanetary missions? Perhaps having a swarm of pico probes launched in the same payload?

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Re: So why can't we bulk produce space probes?

Postby Tass » Sat Jun 29, 2013 6:36 am UTC

scarecrovv wrote:While mass production of the probes themselves may work to reduce costs significantly, launch costs are high


Launch cost is actually a pretty small part of the cost of something like Curiosity

scarecrovv wrote:So either we still have to build a rocket for every one of 100 probes


Or launch more than one of them on each rocket. There is some economies of scale simply by making bigger rockets when it comes to cost/kg to orbit.

scarecrovv wrote: or we have to build a space elevator, launch loop, laser launch facility, scram cannon, or other non-rocket spacelaunch facility


or mass produced reusable rockets. It doesn't necessarily have to be non-rocket. It is still a huge investment though, and it still requires large fligthrates to really be economic. It may be a bit easier to build incrementally, however. SpaceX is attempting this, we'll see how succesful they'll be. The hard limits of fuel cost is more like a factor of 500 cheaper rather than ten, but I'll be contend if we get ten.

Planetary Resources are attempting to spam the solar system with their mass poduced Arkyd probes. They claim that they have reduced the price of such probes by a factor of a hundred. What they are going to miss in capabilities and reliability thay will more than make up for in numbers and redundancy. So basically what the OP wants is on its way.

As a publicity stunt they even made a kickstarter campaign and raised a million dollars to put an extra arkyd 100 up for public use (they are mass producing these anyway and are backed by billionaires so they didn't really need the money, what they wanted was the publicity). It runs for two days more at the time writing, check it out (I think this stuff is so cool that I put it in my sig.).

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Re: So why can't we bulk produce space probes?

Postby idobox » Sat Jun 29, 2013 11:07 am UTC

Ephemeron wrote:Au Contraire. There is plenty of reasons to send probes to other locations. Mars is a big place. This is the very reason why Spirit and Opportunity took such long journeys over the surface of Mars, as it gave them a greater range of places to study. There will always be more of Mars to explore. And that's just Mars.


Curiosity is where it is because it will be able to study stratas, and find out a lot of things about the history of Mars. Could a second, identical, rover find other things somewhere else, sure. Could it find as much new valuable information, I expect not.
I'd rather have the next probe try to do something different, like dig a hole or explore lava tubes, and look for life there.
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Re: So why can't we bulk produce space probes?

Postby Soralin » Sat Jun 29, 2013 8:53 pm UTC

idobox wrote:
Ephemeron wrote:Au Contraire. There is plenty of reasons to send probes to other locations. Mars is a big place. This is the very reason why Spirit and Opportunity took such long journeys over the surface of Mars, as it gave them a greater range of places to study. There will always be more of Mars to explore. And that's just Mars.


Curiosity is where it is because it will be able to study stratas, and find out a lot of things about the history of Mars. Could a second, identical, rover find other things somewhere else, sure. Could it find as much new valuable information, I expect not.
I'd rather have the next probe try to do something different, like dig a hole or explore lava tubes, and look for life there.

Well, you wouldn't have to make it entirely identical, you could potentially benefit by mass producing a standard rover, and then just give each one a different set of science tools and stuff.

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Re: So why can't we bulk produce space probes?

Postby Frenetic Pony » Sat Jun 29, 2013 10:20 pm UTC

Cool enough, Planetary Resources, the crazy guys that want to mine asteroids for a profit, are actually planning on mass producing space telescopes, at least at the very lowest end of "mass produce" that would qualify. Still, they've mentioned up to a hundred small space telescopes already, and this makes sense from their perspective. Launch costs are getting progressively lower as the private space industry gets going, and they care more about scanning as many potential asteroids as possible, rather than just observing a single one as close as possible or some other more "scientific" goal.

If the asteroid mining business takes off we could indeed see space... probes, vehicles? Some sort of manmade objects meant for space rocket into mass production. Pun intended.

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Re: So why can't we bulk produce space probes?

Postby cphite » Mon Jul 01, 2013 2:42 pm UTC

idobox wrote:Also, what is the point of sending two Curiosity?
Identical probes have limited usefulness: redundancy and testing the same stuff somewhere else. Of course, a Mars rover is pretty much useless anywhere but on Mars, and I guess digging holes and shooting lasers in a second valley is not worth spending twice as much.


Bear in mind, they're testing a planet. The location for Curiosity was selected because it was one that looked interesting; that is, it looked interesting based on what little we can see from Earth. But that doesn't mean there aren't other interesting areas. Redundancy is exactly what is needed.

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Re: So why can't we bulk produce space probes?

Postby p1t1o » Mon Jul 01, 2013 2:50 pm UTC

I think the answer is that right now we have no reason to.
I’d be very surprised if there are significant numbers of astro-scientists out there that lack data. The amount of data that is generated by each probe is vaaaast, and we are still coming to terms with reconciling what we have now. Pretty much when one probe outlives its usefulness the next one is launched straightaway anyway.
It’d be cool to have thousands of probes teeming through space, but right now that is about the only reason for it.

Costs are dropping steadily and this will lower the "threshold of need" required to get this sort of mass industry started, but they are only dropping incrementally, something big needs to change in the way we get stuff into space. Launching buttloads of rockets will always be expensive, there is no such thing as "mass producing cheap rockets".

In conclusion, and rather boringly, I think this is simply a question of budgets - no one can afford to do this, when they can, they probably will, but not yet, and for a while. Certainly not until a better way to space is found **COUGH-SKYLON-COUGH**.

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Re: So why can't we bulk produce space probes?

Postby idobox » Mon Jul 01, 2013 5:11 pm UTC

cphite wrote:Bear in mind, they're testing a planet. The location for Curiosity was selected because it was one that looked interesting; that is, it looked interesting based on what little we can see from Earth. But that doesn't mean there aren't other interesting areas. Redundancy is exactly what is needed.

I'm going to reformulate. Sending two identical probes is almost as expensive as two different ones. Sometimes, you want to make the same tests in different places, but more often, it's smarter to use the results of the first probe to design new experiments for the second probe.
For example, Spirit and Opportunity are identical, but their job was to explore the surface and make a catalogue of minerals, so it made sense to send more than one, especially in a region with different geology.
Curiosity, on the other hand, is supposed to look at sedimentary deposits to understand better the history of MArs. We could send a second identical probe somewhere else, to check sediments that are as old, but in a different environment, or we can use the results of Curiosity to design new experiments, or to decide of the most interesting place to visit next.

Personally, I'd love to see a probe exploring the underground rather than a second Curiosity.

If you look at probes launched at comets, you'll see that they are different, and look for different things. We could save money by sending identical probes at different comets, but we would learn so much less.
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Re: So why can't we bulk produce space probes?

Postby p1t1o » Mon Jul 01, 2013 6:22 pm UTC

idobox wrote:If you look at probes launched at comets, you'll see that they are different, and look for different things. We could save money by sending identical probes at different comets, but we would learn so much less.


Totes agree on this too.

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Re: So why can't we bulk produce space probes?

Postby wumpus » Mon Jul 01, 2013 10:18 pm UTC

duplicate post
Last edited by wumpus on Tue Jul 02, 2013 2:57 pm UTC, edited 1 time in total.

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Re: So why can't we bulk produce space probes?

Postby wumpus » Mon Jul 01, 2013 10:18 pm UTC

If you needed to launch enough probes, one way to massively reduce costs would be to use some sort of "space tugboat". Put a spacecraft to at least LEO that has an ion thruster or similar engine and let it slowly take your probe-podTM up to escape velocity. Our trusty tug boat would then loop around the moon and slowly make its way back to Earth for the next shipment (I have no idea if atmospheric breaking will work. My guess is that you would fit the solar panels as fins and have highly insulated aerobrakes to brake, but whether the resulting highly elliptical orbit would help you is anybody's guess (maybe you could use a lunar decelerating slingshot)).

Personally, I would use a space tug for manned exploration. The first task would be to take any lunar landing gear and lunar base equipment to lunar orbit. Such a tug would be even better for Mars (I'm assuming it would make the whole trip, but it is conceivable that you would have a thrower and catcher tugs on each planet. This would allow you a much higher throughput, although not much higher when you consider the effects of constant acceleration.

Finally, standard procedure for NASA (pre-shuttle, at least) was always to make two probes. Presumably most of the money went into the design of the probes, and building the second one didn't add all that much to the cost compared to the insurance that there was a much higher chance of at least one successful probe mission. I'm pretty sure someone on a xkcd board asked why all the Apollo missions, it turns out that there were at least as many Saturn rockets made for missions just learning to get to the moon (pre-Apollo 11) as Saturn rockets made to go to the moon after we had been there once.

I'm guessing that with the ease of designing [relatively] ultramicroscopic circuitry and the rocket equation being as painful as ever, the cost of building a second probe isn't comparable to the cost of launching to escape velocity. Expect the economics to change if you throw in a space tugboat: we might actually mass produce certain types of probes.

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Re: So why can't we bulk produce space probes?

Postby idobox » Tue Jul 02, 2013 9:51 am UTC

wumpus wrote:If you needed to launch enough probes, one way to massively reduce costs would be to use some sort of "space tugboat"

An alternative would be to put a slingshot or catapult in LEO. A tugboat needs refuelling, a catapult can manage recoil by firing at appropriate times.
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Re: So why can't we bulk produce space probes?

Postby wumpus » Tue Jul 02, 2013 3:08 pm UTC

idobox wrote:
wumpus wrote:If you needed to launch enough probes, one way to massively reduce costs would be to use some sort of "space tugboat"

An alternative would be to put a slingshot or catapult in LEO. A tugboat needs refuelling, a catapult can manage recoil by firing at appropriate times.


I can't see how either ship would manage without refueling, and both would almost certainly use solar panels. If you can pull of enough trickiness to avoid recoil (I'm sure there are means available, either firing in offsetting directions or orbital trickiness) you will have multiple times the efficiency (assuming the moment of inertia of the slingshot/catapult is significantly less than the mass of the tug).

Note that pretty much anything that involves re-launching in space severely limits launch windows for probes. The path the Voyagers had was so perfect this type of contraption might have been ignored simply to hit the launch windows.

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Re: So why can't we bulk produce space probes?

Postby idobox » Tue Jul 02, 2013 4:02 pm UTC

wumpus wrote:I can't see how either ship would manage without refueling

There are a few ways.
You can time your shootings to offset each other, but that can be complex.
You can also use electrodynamic tethers or magnetic sails.
As an extreme case, you can even use aero-braking. There will be aerobraking anyway, but you could fire your probes in a way to compensate for it, thus reducing altitude control fuel requirements.
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Re: So why can't we bulk produce space probes?

Postby Sandor » Wed Jul 03, 2013 7:32 am UTC

idobox wrote:I'm going to reformulate. Sending two identical probes is almost as expensive as two different ones. Sometimes, you want to make the same tests in different places, but more often, it's smarter to use the results of the first probe to design new experiments for the second probe.

ESA's Venus Express is very similar to Mars Express, as a lot of the design and instruments were copied to save money. I believe there are some benefits, scientifically, to having the same instruments studying the atmospheres of both planets. Rosetta also has lot in common with both spacecraft.

Of course, there's also NASA's Pioneer probes and the Voyagers that followed them. And don't forget Spirit and Opportunity.

I'm sure there are many other examples were it was beneficial to use (almost) identical spacecraft. I imagine that a lot of communications satellites are similar if not identical. Of course, none of this is exactly the mass production the OP was asking about.

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Re: So why can't we bulk produce space probes?

Postby idobox » Wed Jul 03, 2013 2:01 pm UTC

Good examples of situations where you measure similar properties in different places.
It makes sense to send similar probes to study the atmosphere of Mars and Venus, not so much to send two identical probes to study the atmosphere of the same planet.
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Re: So why can't we bulk produce space probes?

Postby Jorpho » Fri Jul 05, 2013 3:54 am UTC

Ephemeron wrote:The outer planets are just begging for exploration. It's almost criminal that Uranus and Neptune have only been visited once, by Voyager 2 in the '80s.
Didn't that require an exceptionally rare planetary alignment to pull off? Of course, Voyager stopped at all the planets along the way, and they are sending that probe out to Pluto at the moment, but nonetheless it's not as easy as point-and-shoot-whenever. Is it?

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Re: So why can't we bulk produce space probes?

Postby thoughtfully » Fri Jul 05, 2013 4:54 am UTC

Jorpho wrote:it's not as easy as point-and-shoot-whenever. Is it?

Depends on destination. It might be if a nuclear propulsion system was used.
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Re: So why can't we bulk produce space probes?

Postby idobox » Fri Jul 05, 2013 2:35 pm UTC

Jorpho wrote:
Ephemeron wrote:The outer planets are just begging for exploration. It's almost criminal that Uranus and Neptune have only been visited once, by Voyager 2 in the '80s.
Didn't that require an exceptionally rare planetary alignment to pull off? Of course, Voyager stopped at all the planets along the way, and they are sending that probe out to Pluto at the moment, but nonetheless it's not as easy as point-and-shoot-whenever. Is it?

Voyager didn't just stopped at planets on the way, it used them as slingshots. If you do it right, passing by planets gives you free deltaV, which you can use to go further from the sun.
You can always do a point and shoot, but then you loose that free deltaV, which means less payload. Luckily, if you're not in a hurry, you can use the Oberth effect to get a lot of deltaV for cheap.
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Re: So why can't we bulk produce space probes?

Postby johnny_7713 » Fri Jul 05, 2013 9:48 pm UTC

Sandor wrote:I'm sure there are many other examples were it was beneficial to use (almost) identical spacecraft. I imagine that a lot of communications satellites are similar if not identical. Of course, none of this is exactly the mass production the OP was asking about.


Many communication satellites are indeed built off a common base and of course satellites in a constellation (e.g. GPS) are likely mostly identical. Even so there's not going to be a market for real mass production, especially if we talk about probes for exploration, so the benefits of mass production will be limited. Consider for example aircraft; the most successful aircraft families at the moment are the Boeing 737 and the Airbus A32X. They are both churned out at a rate of 40-odd per month. Even so the list price for one of these aircraft is in the order of $75-100 million.

`Mass' production of probes would allow you to smear out the development cost over more probes and to reduce the production costs a bit (making use of economies of scale), but you would never get into the volumes required for real mass production (i.e. several per day, if not per hour).

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Re: So why can't we bulk produce space probes?

Postby PM 2Ring » Sat Jul 06, 2013 8:34 am UTC

Gravitational assist can certainly give you big fuel savings, but the alignments required for such trajectories are not frequent, especially if you want to visit several planets like the Voyagers did.

http://en.wikipedia.org/wiki/Planetary_Grand_Tour wrote:The Planetary Grand Tour was an ambitious plan to send unmanned probes to the planets of the outer Solar System. Conceived by Gary Flandro of the Jet Propulsion Laboratory in 1964,[1][2] the Grand Tour would have exploited the alignment of Jupiter, Saturn, Uranus, Neptune, and Pluto, an event that would occur in the late 1970s, and not recur for 175[citation needed] years. A probe sent to Jupiter could use that planet as a gravitational slingshot to extend its trajectory to planets further out in the Solar System.

The original proposed mission design had four probes. The first two, with proposed launch dates in 1976 and 1977, were to fly by Jupiter, Saturn, and Pluto. The other two, with proposed launch dates in 1979, were to fly by Jupiter, Uranus, and Neptune.

The vehicles were to have been designed with multiple redundant systems to ensure reliability over missions lasting up to 12 years.

NASA budget cuts eventually doomed the Grand Tour missions in 1972, as well as later proposals for a "mini grand tour". However, many elements of the Grand Tour were added to the Voyager program. The two Voyager probes, launched in 1977, were originally meant to fly by Jupiter and Saturn. The Voyager 2 mission used the fortunate alignments of the outer planets and was extended to include close flybys of both Uranus and Neptune. Voyager 2's mission has specifically come to be regarded as the "Grand Tour".

Voyager 1 could have been sent to Pluto after Saturn, but was instead sent on a trajectory that brought it close by Titan, eliminating the Pluto flyby. Voyager 2's trajectory could not be altered to bring the probe by Pluto after the Neptune flyby in 1989.


http://en.wikipedia.org/wiki/Interplanetary_Transport_Network wrote:The Interplanetary Transport Network (ITN)[1] is a collection of gravitationally determined pathways through the Solar System that require very little energy for an object to follow. The ITN makes particular use of Lagrange points as locations where trajectories through space are redirected using little or no energy. These points have the peculiar property of allowing objects to orbit around them, despite the absence of any material object therein. While they use little energy, the transport can take a very long time.

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Re: So why can't we bulk produce space probes?

Postby ikrase » Tue Jul 16, 2013 1:38 am UTC

THere is significant interest in modular space probe equipment, and many space probes use modifications or straight duplicates of instruments intended for earlier vehicles.
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