Author Topic: NASA - Europa Clipper updates and discussion  (Read 350566 times)

Offline WolfganP

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Re: NASA - Europa Clipper updates and discussion
« Reply #1060 on: 10/30/2024 01:20 pm »
The doubling of the MERS rovers doubled the mission budget from around $400 million to about $800 million.  I think Squyres’ account above squares with that.  There were no economies of scale that made the second rover less expensive than the first, which is consistent with modern research on learning curves.  You don’t usually see improvement until many more repetitions.  I covered NASA Space Science at OMB at the time and supported the increase because of MCO/MPL failures, not because of any “savings”, which did not exist.

The cost over budget is attributed to redesign in the story above, that will impact the 1st rover and not the replication tasks. Most likely proper attribution may show that they run way over the 400M mark for the first rover (if they have planned to launch just one), and the manufacturing of the duplicate pieces for the 2nd rover being just that, manufacturing costs. They may have missed also their estimation for these costs as well, but there certainly are economies of scale in manufacturing and purchasing once you know what to build and buy around.

Online Blackstar

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Re: NASA - Europa Clipper updates and discussion
« Reply #1061 on: 10/30/2024 02:13 pm »
They may have missed also their estimation for these costs as well, but there certainly are economies of scale in manufacturing and purchasing once you know what to build and buy around.

There are reasons to believe that the economies of scale don't show up until you're dealing with multiples (five or more). Two or three probably doesn't achieve much, because they are still being hand made and efficiencies don't occur at low numbers. Think about it this way--when you make one of something, you make a bunch of mistakes. When you make two, you can avoid some of the mistakes on the second one. But you don't get good at it until you have done it many times and start looking for efficiencies in time and money.


Offline mn

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Re: NASA - Europa Clipper updates and discussion
« Reply #1062 on: 10/30/2024 03:51 pm »
They may have missed also their estimation for these costs as well, but there certainly are economies of scale in manufacturing and purchasing once you know what to build and buy around.

There are reasons to believe that the economies of scale don't show up until you're dealing with multiples (five or more). Two or three probably doesn't achieve much, because they are still being hand made and efficiencies don't occur at low numbers. Think about it this way--when you make one of something, you make a bunch of mistakes. When you make two, you can avoid some of the mistakes on the second one. But you don't get good at it until you have done it many times and start looking for efficiencies in time and money.

We don't really make things by hand most of the time, we use machinery, and those machines need to be setup for the specific task. So making two of each vs one of each should most definitely take less time (obviously not the efficiency gains of mass production, but I would hope a certain nice chunk of savings).

Order two chunks of steel, setup/program the cnc machine, insert block of steel, press 'go', remove cut piece, inspect, insert next chunk of steel and press 'go' again. (and for that price, if the raw material is not too expensive, insert 3rd chunk so you have a spare part for very little additional cost)

Offline Eric Hedman

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Re: NASA - Europa Clipper updates and discussion
« Reply #1063 on: 10/30/2024 05:41 pm »
They may have missed also their estimation for these costs as well, but there certainly are economies of scale in manufacturing and purchasing once you know what to build and buy around.

There are reasons to believe that the economies of scale don't show up until you're dealing with multiples (five or more). Two or three probably doesn't achieve much, because they are still being hand made and efficiencies don't occur at low numbers. Think about it this way--when you make one of something, you make a bunch of mistakes. When you make two, you can avoid some of the mistakes on the second one. But you don't get good at it until you have done it many times and start looking for efficiencies in time and money.

We don't really make things by hand most of the time, we use machinery, and those machines need to be setup for the specific task. So making two of each vs one of each should most definitely take less time (obviously not the efficiency gains of mass production, but I would hope a certain nice chunk of savings).

Order two chunks of steel, setup/program the cnc machine, insert block of steel, press 'go', remove cut piece, inspect, insert next chunk of steel and press 'go' again. (and for that price, if the raw material is not too expensive, insert 3rd chunk so you have a spare part for very little additional cost)
For individual parts manufacturing, this is definitely true.  For assembling 40,000 parts into a finished spacecraft this is not true.  It is incredibly labor intensive and will not be cheap to do a second copy.  If you discover through the assembly process that something doesn't work right and needs to be redesigned.  You now have twice the rework.

Offline vjkane

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Re: NASA - Europa Clipper updates and discussion
« Reply #1064 on: 10/30/2024 05:51 pm »
We don't really make things by hand most of the time, we use machinery, and those machines need to be setup for the specific task. So making two of each vs one of each should most definitely take less time (obviously not the efficiency gains of mass production, but I would hope a certain nice chunk of savings).

Order two chunks of steel, setup/program the cnc machine, insert block of steel, press 'go', remove cut piece, inspect, insert next chunk of steel and press 'go' again. (and for that price, if the raw material is not too expensive, insert 3rd chunk so you have a spare part for very little additional cost)
I believe that projects already build one to many spares, so the hardware cost isn't the driving factor.

Offline ccdengr

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Re: NASA - Europa Clipper updates and discussion
« Reply #1065 on: 10/30/2024 06:08 pm »
I believe that projects already build one to many spares...
Depends on what level of assembly, but generally not more than one, if that.  It's pretty unusual to be able to build more than one spare spacecraft instrument, in my experience.  Spare electronics, spare mechanical components, yes, but the assembly process is hands-on and labor intensive.  Very few projects build an entire spare spacecraft any more.

Offline Spiff

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Re: NASA - Europa Clipper updates and discussion
« Reply #1066 on: 10/30/2024 07:13 pm »
A post that doesn't really belong here, but I don't know where else to put it. (Mods can remove it if so desired).

Shoutout to Blackstar, VSECOTSPE, vjkane, and some others for their great insights into the background processes that go into these missions. On so many of the subforums here I switch to TL;DR mode whenever there's a speculative 'yes it is! no it isn't' discussion going on. But your posts I always read.

Fascinating to hear all these background stories about why or why not things have played out the way they have or have not.

Thanks guys. Keep enlightening me and the other amateurs here!
I always consider space to be the FIRST frontier.

Online Blackstar

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Re: NASA - Europa Clipper updates and discussion
« Reply #1067 on: 10/30/2024 07:30 pm »
We don't really make things by hand most of the time, we use machinery, and those machines need to be setup for the specific task.

You're being a bit too literal in reading what I wrote.

Offline redliox

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Re: NASA - Europa Clipper updates and discussion
« Reply #1068 on: 10/30/2024 08:07 pm »
Has there been any further updates on the trajectory burn or instrument deployments?  I was told some would happen around the 5th or so.
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Offline vjkane

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Re: NASA - Europa Clipper updates and discussion
« Reply #1069 on: 10/30/2024 09:30 pm »
I believe that projects already build one to many spares...
Depends on what level of assembly, but generally not more than one, if that.  It's pretty unusual to be able to build more than one spare spacecraft instrument, in my experience.  Spare electronics, spare mechanical components, yes, but the assembly process is hands-on and labor intensive.  Very few projects build an entire spare spacecraft any more.
I was referring to the component level since that was the claim of the original post, not assembled level.

Offline jcm

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Re: NASA - Europa Clipper updates and discussion
« Reply #1070 on: 10/30/2024 10:45 pm »
Has there been any further updates on the trajectory burn or instrument deployments?  I was told some would happen around the 5th or so.

I'm told the first TCM will be on Sunday.
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Online Blackstar

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Re: NASA - Europa Clipper updates and discussion
« Reply #1071 on: 10/31/2024 01:11 am »
I'm not opposed to a little thread drift as long as we come back to the baseline. I think that when this thread has lots of updates for Clipper, then there should probably be separate update and discussion threads. Unfortunately, JPL doesn't seem to be updating much.

So allow me to go back to the "how much does it cost to build two?" discussion a bit with this link:

https://www.thespacereview.com/article/2813/1

I wrote that way back in 2015 about a proposal way way back in 2002 by the New Horizons team that they could build a second New Horizons spacecraft for about 60% of the cost of the first. A review team was appointed in 2005 to look into the issue, and they concluded that whereas the projected cost of New Horizons at that time was $723 million, the second one could be built for about $100 million less (so about 86% of the original cost, not 60%).

Now lots and lots of things affect those kinds of estimates, but it is another example that demonstrates that you cannot assume that building a second one is going to be a lot cheaper than the first.



Addendum: At least one of the things that could affect how much it costs is if spares already exist for unit number 1 that could be applied to unit number 2. But I think one of the biggest factors is when unit number 2 is approved. If they are both approved around the same time, you save more money than if you make the decision later.

One more thing is that when Alan Stern made that proposal it took a lot of chutzpah. The New Frontiers funding line had just been created as a competed mission line, and New Horizons was selected as the first New Frontiers mission. But Stern was essentially proposing that NH2 be awarded as the second New Frontiers mission by fiat, not competition. People were annoyed, which is why Congress asked for an independent review, which said that this was a bad idea.
« Last Edit: 10/31/2024 01:20 am by Blackstar »

Online Blackstar

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Re: NASA - Europa Clipper updates and discussion
« Reply #1072 on: 10/31/2024 01:12 am »
And to try to keep us a bit on-topic, here is a useless award from Time magazine, which is apparently a thing that still exists.

Offline Don2

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Re: NASA - Europa Clipper updates and discussion
« Reply #1073 on: 10/31/2024 03:30 am »

The doubling of the MERS rovers doubled the mission budget from around $400 million to about $800 million.  I think Squyres’ account above squares with that.  There were no economies of scale that made the second rover less expensive than the first, which is consistent with modern research on learning curves.  You don’t usually see improvement until many more repetitions.  I covered NASA Space Science at OMB at the time and supported the increase because of MCO/MPL failures, not because of any “savings”, which did not exist.

Squyres's account doesn't support what you say. He says that it was redesign of the lander, the parachute and the airbags that drove up costs. Getting the design right costs the same regardless of the number of landers built.

He also has the same "50% extra for a second copy" that I have seen in other sources.

I don't think that has anything to do with learning curves. It is common in aerospace to spend a lot on developing a design and doing the testing to prove it will work. The development cost of the A350 airliner was in the $10-15 billion range. That money has to be spent to certify the design and put the first aircraft into service. The cost of the subsequent aircraft is just the manufacturing cost. The A-350 probably sells for about $160 million each ( actual sales prices are secret), so the incremental cost of additional airliners is two orders of magnitude less than the cost of building the first one.

For planetary probes there must be a somewhat similar process of testing and simulation to prove that the design will work. That bill has to be paid regardless of the number of units produced. It probably varies a lot from project to project.

The "learning curve" is a different issue. The rule of thumb in airliner manufacturing is that the unit cost falls by 15% each time the cumulative production doubles as long as the units are identical designs built by the same workforce. Similar learning curves are very common in other manufacturing situations, but the decline rate isn't always 15%.

Offline Don2

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Re: NASA - Europa Clipper updates and discussion
« Reply #1074 on: 10/31/2024 03:40 am »

So allow me to go back to the "how much does it cost to build two?" discussion a bit with this link:

https://www.thespacereview.com/article/2813/1

I wrote that way back in 2015 about a proposal way way back in 2002 by the New Horizons team that they could build a second New Horizons spacecraft for about 60% of the cost of the first. A review team was appointed in 2005 to look into the issue, and they concluded that whereas the projected cost of New Horizons at that time was $723 million, the second one could be built for about $100 million less (so about 86% of the original cost, not 60%).


I read your article, and it states that they didn't have an RTG available for New Horizons 2 (NH2), so they were planning to launch it five years later. They weren't using the same people to build the same spacecraft at the same time. The might have had to modify the design if some components went out of production, which could happen if the builds were several years apart.

Offline VSECOTSPE

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Re: NASA - Europa Clipper updates and discussion
« Reply #1075 on: 10/31/2024 03:19 pm »
Squyres’ account doesn't support what you say.

It does.  Squyres wrote:

Quote from: Steve Squyres, Roving Mars (2005)
Their answer was $665 million, compared to the $440 million we had figured it would cost to do one. Fifty percent increase, more or less...

... Back when we’d had our budget “cap” of $688 million, the IRT had predicted that we would overrun it by something between $84 and $154 million.

...and now when we added it all up, it looked like we were going to come in at something very close to $800 million.

And I wrote:

The doubling of the MERS rovers doubled the mission budget from around $400 million to about $800 million.

I saw the cost for one MERS rover of ~$400M from NASA and the cost for two MERS rovers of ~$800M from NASA.  Squyres also starts at ~$400M and saw the interim steps, which he says included an immediate ~50% increase for the second MERS rover and an independent cost delta for two rovers that got the two rovers up to ~$800M.  My numbers and Squyres’ numbers roughly align.

Quote
He says that it was redesign of the lander, the parachute and the airbags that drove up costs.

No, Squyres wrote that there was an immediate 50% add for the second MERS rover.  And his narrative shows that having a second MERS rover didn’t save anything when the program had to re-engineer certain elements of the missions.  That’s not surprising because the industrial psychology research on learning curves shows that learning doesn’t generate improved processes that produce cost savings until much higher levels of production are reached.  MERS would have needed a (unneeded) third, a fifth, or a tenth rover to reap the benefits of such redesigns.

I read your article, and it states that they didn't have an RTG available for New Horizons 2 (NH2), so they were planning to launch it five years later.

“They” here is the independent review of NH2, not the internal advocates on the NH team.  And what BlackStar is pointing out is that when (more) realistic cost estimates of doubled spacecraft missions are developed by independent teams, they show little or no savings from the second spacecraft, for a variety of reasons (RTG availability in this case).  The rule of thumb holds — when you go from one to two spacecraft, you’re going to approximately double the mission cost.

There’s no doubt that constellations of thousands of spacecraft like StarLink can and do benefit from learning curves and economies of scale.  There are some science mission concepts, mainly in heliophysics and astrophysics, that involve hundred of identical spacecraft or tens of identical instruments that could benefit from learning curves and economies of scale.  But we’re not going to see savings with onesie-twosie duplicate spacecraft.  That’s not far enough down the learning curve to see the benefits.  It’s especially not true when dealing with limited resources like RTGs, large therm-vac chamber thruput, university instrument labs, etc.  There are huge differences between what planetary science does and what a spacecraft factory for a LEO comsat constellation does.  The latter really does not apply to the former. 

Offline Don2

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Re: NASA - Europa Clipper updates and discussion
« Reply #1076 on: 10/31/2024 03:29 pm »
This discussion might be relevant to the issue of a Europa lander to follow up on the discoveries of Europa Clipper. There was a study for a Europa lander and I remember that the cost came out at around $5 billion. The lander wasn't very large and it only lasted about a month because of the radiation. If the reason for the high cost was because of the difficulty of developing the radiation hardened electronics, then this is the kind of situation where the cost of the second lander might be a lot less than the cost of the first one.

Experience curves are a different issue, and they probably aren't relevant to science spacecraft because they are never produced in large numbers. Here is a link to a short Wikipedia article on them. They were originally identified in aircraft manufacturing by Theodore Wright.
https://en.wikipedia.org/wiki/Experience_curve_effects

Europa Lander study
https://europa.nasa.gov/resources/58/europa-lander-study-2016-report/
This was a battery powered lander with  20 Earth day lifetime launched on SLS. Launching on Starship would be an obvious cost reduction move. Planetary protection was a major consideration, and they used a skycrane to reduce the contamination of the surface with the rocket plumes. In my opinion the surface of Europa is likely to be sterilized by the local radiation. The radiation would be likely to degrade or destroy any local organic molecules, thus making it hard to detect signs of life.

Online Blackstar

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Re: NASA - Europa Clipper updates and discussion
« Reply #1077 on: 10/31/2024 04:10 pm »
when (more) realistic cost estimates of doubled spacecraft missions are developed by independent teams, they show little or no savings from the second spacecraft, for a variety of reasons (RTG availability in this case).  The rule of thumb holds — when you go from one to two spacecraft, you’re going to approximately double the mission cost.

Yeah, I was going to point out something like that. There is the old saying that the devil is in the details, and this is an example of one of those details. The NH team probably just assumed that there was another RTG ready for them to use, but there wasn't. It's stuff like that that trips up people/teams when it comes to actual implementation.

As a side example, I think that up-thread we were discussing cost estimating (or maybe that was on the Dragonfly thread?) and I mentioned how humans are bad at cost estimating LOTS of things, including non-high-tech things like road and tunnel projects. Back in the 2000s there was a big highway project on the outskirts of Washington, DC, at a location where I-95, I-395, and I-495 (known as "the Beltway") all come together. I believe that at the time it was known as "the mixing bowl" and was notorious for traffic jams. The project was to untangle all the roads and fix traffic (note: it essentially did this). But the project blew past its cost estimate for a bunch of reasons. One reason was that construction was taking off in China, which drove up the cost of concrete in the United States. That's kinda amazing because we think of concrete as low-tech and local. But there was another reason, which was that the original cost estimate assumed that the project could take over land belonging to a local high school and used for their football field. They figured that it was government land and belonged to the county and would therefore be free to acquire. Except that the high school complained and so the highway project needed to acquire new land for a new football field, costing money that was not in the original estimate.

Yeah, what does this have to do with space? Well, it's an example that project proposers making cost estimates often optimistically assume they will get certain things for free or low cost, like a football field or an RTG, and then reality steps in.



economies of scale.  There are some science mission concepts, mainly in heliophysics and astrophysics, that involve hundred of identical spacecraft or tens of identical instruments that could benefit from learning curves and economies of scale.  But we’re not going to see savings with onesie-twosie duplicate spacecraft.  That’s not far enough down the learning curve to see the benefits.

A number of years ago the Academies did a study of cubesats for space science. There are indeed a few missions where a lot of inexpensive smallsats could be useful for space science. But there are also hurdles to making that work. Most smallsats do not carry instruments/equipment built to very high precision standards like scientific instruments. If the mission could be done with hundreds of smallsats that require hundreds of high-precision instruments, there may be no way to manufacture the instruments less expensively.

Offline vjkane

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Re: NASA - Europa Clipper updates and discussion
« Reply #1078 on: 10/31/2024 04:14 pm »
I read your article, and it states that they didn't have an RTG available for New Horizons 2 (NH2), so they were planning to launch it five years later. They weren't using the same people to build the same spacecraft at the same time. The might have had to modify the design if some components went out of production, which could happen if the builds were several years apart.
Here is the actual quote from Blackstar's article: "NH 2 was billed as a backup to New Horizons, using identical systems and instruments and counting on the fact that it is possible to build a second copy of a spacecraft significantly cheaper than the first—perhaps only 60 percent as much—provided that procurement is started at the same time as the first. "

This sounds like a project best estimate/guess, not an estimate following a thorough review. Project estimates very often are very off.

Offline Don2

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Re: NASA - Europa Clipper updates and discussion
« Reply #1079 on: 10/31/2024 04:17 pm »

I saw the cost for one MERS rover of ~$400M from NASA and the cost for two MERS rovers of ~$800M from NASA.  Squyres also starts at ~$400M and saw the interim steps, which he says included an immediate ~50% increase for the second MERS rover and an independent cost delta for two rovers that got the two rovers up to ~$800M.  My numbers and Squyres’ numbers roughly align.


I have a paper copy of "Roving Mars", and Squyres explains what happened. Using airbags to land a payload as heavy as a MER rover almost didn't work. The initial tests of the Pathfinder airbags resulted in catastrophic failure. They beefed up the airbags to the point where they could do the job if the horizontal velocity was limited. Then they added another system to sense and zero out the horizontal velocity.

One reason the cost of projects can blow up is if a core technology just doesn't work. That almost happened to MER.

Another problem was that the initial parachute designs failed.

Both problems had to be solved regardless of the number of rovers built. Solving them was expensive.

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