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.
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.
Quote from: WolfganP on 10/30/2024 01:20 pmThey 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.
Quote from: Blackstar on 10/30/2024 02:13 pmQuote from: WolfganP on 10/30/2024 01:20 pmThey 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)
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...
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.
Quote from: vjkane on 10/30/2024 05:51 pmI 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.
Has there been any further updates on the trajectory burn or instrument deployments? I was told some would happen around the 5th or so.
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/2813/1I 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%).
Squyres’ account doesn't support what you say.
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.
The doubling of the MERS rovers doubled the mission budget from around $400 million to about $800 million.
He says that it was redesign of the lander, the parachute and the airbags that drove up costs.
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.
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.
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.
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.
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.