Quote from: Blackstar on 02/02/2022 04:50 pmI think that most major programs divide up their reserves and the program manager has some reserves, but the AA also has some reserves. So the program manager is required to fix their problems using their own reserves, but if they have to, they can appeal to the AA for some of their reserves. That's not something they do lightly, because it's the equivalent to going to the boss for more money.That’s right. For most missions in development, some percentage of reserves are held at HQ, and the PM has to have a come-to-Jesus review with the AA to access those HQ reserves. HQ reserves are not about the money per se. They’re really a tool to force discussions on missions that are in some trouble.Paradoxically, there is a positive correlation between reserves (of any kind, program or HQ) and budget overruns. The bigger your reserves, the bigger your likely budget overrun. This is probably related to mission size and complexity, but there may be also some moral hazards associated with reserves and there is a never-ending debate over appropriate/optimal reserve levels.
I think that most major programs divide up their reserves and the program manager has some reserves, but the AA also has some reserves. So the program manager is required to fix their problems using their own reserves, but if they have to, they can appeal to the AA for some of their reserves. That's not something they do lightly, because it's the equivalent to going to the boss for more money.
Quote from: Blackstar on 01/31/2022 08:08 pmQuote from: Jim on 01/31/2022 06:56 pmJPL is responsible for the total design and has to trade payload vs spacecraft requirements.I heard something last year while working on the planetary decadal survey and I cannot remember the specifics, but there's actually a set of guidelines about who can ultimately trade off payload--and science--for spacecraft requirements. In other words, NASA has specific rules that say that "Person X can decide that some science cannot be done and remove that from the mission in order to accomplish other mission goals." They get the last word, although they will have to justify those decisions to the associate administrator.The context of that is important, because the scientific community has established high-level science goals for the mission, and then through a series of steps, turned those into specific science goals for the mission. And they become very attached to those goals and mad if they are not going to be achieved. But somebody actually has to make the mission work, and it is possible that something like a fuel or mass margin requires losing some of the science (not always deleting a payload, but maybe not performing observations or not allocating comm to a payload). I think that this discussion came up because of the magnetometer issue, when JPL had to accept much lower science, and members of the community were really upset and asked how they could do that, because the science requirements were clear. NASA has put in place rules that give certain people the power to do that. They have to. It's necessary when managing complex programs. I'm sure JWST operated under similar rules. I was thinking about this a bit more and a bit more of my memory came back. The issue was over who "owns" the science requirements for a science mission. And the answer that came back from NASA was that in the end, it is the program manager (who is an engineer and not a scientist) who "owns" those requirements and can trade them off for other factors, like mission success, margins (safety, fuel, mass), etc.When you dig really far down into Europa Clipper, you can find some scientists who are not happy with the quality of the science that the mission will do. They wanted something that would achieve X, Y, and Z, and what they're getting is something that will achieve X-1, Y-1, and Z-1 instead. But that's not true for all of the scientists, and some of them may be unhappy that they are not getting everything they want, but happy that they are getting something. It's a matter of how much some people complain, because just about everybody can complain.I think that this issue of "ownership" of the science requirements also came up with Perseverance with landing site selection, and you can probably find mention of that in the Perseverance threads. There the issue was who had the final say in where the rover landed, and it really rested with the person who ran the mission based on engineering considerations. And if you take a broad enough perspective, and look at historical examples, you will find that this kind of stuff happened throughout the planetary space program. An example was the tradeoffs for a moveable instrument platform on Cassini vs. fixed instruments that required the spacecraft to turn and point for observations and limited simultaneous observations. The scientists wanted a moveable instrument platform. But at some point, somebody had to make a call on that, and they calculated that eliminating the platform would save a lot of money and that was more important to the program. In the end, somebody has to be authorized to make the tough calls on mission design.
Quote from: Jim on 01/31/2022 06:56 pmJPL is responsible for the total design and has to trade payload vs spacecraft requirements.I heard something last year while working on the planetary decadal survey and I cannot remember the specifics, but there's actually a set of guidelines about who can ultimately trade off payload--and science--for spacecraft requirements. In other words, NASA has specific rules that say that "Person X can decide that some science cannot be done and remove that from the mission in order to accomplish other mission goals." They get the last word, although they will have to justify those decisions to the associate administrator.The context of that is important, because the scientific community has established high-level science goals for the mission, and then through a series of steps, turned those into specific science goals for the mission. And they become very attached to those goals and mad if they are not going to be achieved. But somebody actually has to make the mission work, and it is possible that something like a fuel or mass margin requires losing some of the science (not always deleting a payload, but maybe not performing observations or not allocating comm to a payload). I think that this discussion came up because of the magnetometer issue, when JPL had to accept much lower science, and members of the community were really upset and asked how they could do that, because the science requirements were clear. NASA has put in place rules that give certain people the power to do that. They have to. It's necessary when managing complex programs. I'm sure JWST operated under similar rules.
JPL is responsible for the total design and has to trade payload vs spacecraft requirements.
Quote from: VSECOTSPE on 02/03/2022 03:05 amQuote from: Blackstar on 02/02/2022 04:50 pmI think that most major programs divide up their reserves and the program manager has some reserves, but the AA also has some reserves. So the program manager is required to fix their problems using their own reserves, but if they have to, they can appeal to the AA for some of their reserves. That's not something they do lightly, because it's the equivalent to going to the boss for more money.That’s right. For most missions in development, some percentage of reserves are held at HQ, and the PM has to have a come-to-Jesus review with the AA to access those HQ reserves. HQ reserves are not about the money per se. They’re really a tool to force discussions on missions that are in some trouble.Paradoxically, there is a positive correlation between reserves (of any kind, program or HQ) and budget overruns. The bigger your reserves, the bigger your likely budget overrun. This is probably related to mission size and complexity, but there may be also some moral hazards associated with reserves and there is a never-ending debate over appropriate/optimal reserve levels. If I'm even close to reading that right (probably not) do you mean there's a problem with some folks considering reserves as simply part of the budget, and sort of defeating the purpose?
If I'm even close to reading that right (probably not) do you mean there's a problem with some folks considering reserves as simply part of the budget, and sort of defeating the purpose?
Although it was impossible to tell from our limited data set whether the existence of mission cost reserves increases the likelihood of mission cost increases, it was clear from this quantitative research that the amount of mission cost reserves correlates strongly with the amount of mission cost increases. This relationship was also strong between dollars of mission reserves and dollars of spacecraft and payload cost increase.
Quote from: Nomadd on 02/03/2022 04:12 amIf I'm even close to reading that right (probably not) do you mean there's a problem with some folks considering reserves as simply part of the budget, and sort of defeating the purpose?This paper will do a better explaining the phenomenon than anything I can write here. “Moral hazard” is explained on the second page. After crunching some mission cost data, their conclusion is:QuoteAlthough it was impossible to tell from our limited data set whether the existence of mission cost reserves increases the likelihood of mission cost increases, it was clear from this quantitative research that the amount of mission cost reserves correlates strongly with the amount of mission cost increases. This relationship was also strong between dollars of mission reserves and dollars of spacecraft and payload cost increase.https://ntrs.nasa.gov/api/citations/20120002314/downloads/20120002314.pdfHere’s a related presentation:https://www.nasa.gov/sites/default/files/files/20_AO_reserve_policy_TAGGED.pdf
How often does JPL/Caltech show off what it's building? I ask because I'd love to see 'Clipper, even through a cleanroom window, before launch day.
Thomas Zurbuchen, Associate Administrator for the Science Mission Directorate, told members of the Space Studies Board and Aeronautics and Space Engineering Board that Europa Clipper remains on track for launch in 2024 after successfully clearing Key Decision Point-D (KDP-D) in March. That marks the transition from Phase C, final design and fabrication into Phase D, assembly, integration and test, and launch. It is followed by Phase E, operations and sustainment.<snip>The mission is still very expensive. Zurbuchen said today “we changed the agency baseline commitment from $4.25 billion to $5 billion” and “make no mistake, we’re nowhere near out of the woods on this one yet. Integration and test is where things usually get really, really hard.”<snip>About $100 million of the increase is for additional reserves in Phase D, and he also mentioned about $100 million due to COVID, but the bulk is in Phase E to have a career and talent pipeline program recognizing the long timeframe of the mission. “I have no joy in telling you that we need more money for Phase E” but “if I had to choose” which phase to add money for “it would be Phase E because that’s where we do the science.”
I'm super psyched to hear that ALL instruments passed, including the problem child one.
Quote from: deadman1204 on 03/23/2022 02:03 pmI'm super psyched to hear that ALL instruments passed, including the problem child one.If you are referring to the magnetometer, I'd note that they replaced the original magnetometer with a new, less sensitive one.
Quote from: Blackstar on 03/25/2022 12:33 pmQuote from: deadman1204 on 03/23/2022 02:03 pmI'm super psyched to hear that ALL instruments passed, including the problem child one.If you are referring to the magnetometer, I'd note that they replaced the original magnetometer with a new, less sensitive one.How sensitive is it compared to Galileo or perhaps Juno?
Quote from: redliox on 03/25/2022 01:18 pmQuote from: Blackstar on 03/25/2022 12:33 pmQuote from: deadman1204 on 03/23/2022 02:03 pmI'm super psyched to hear that ALL instruments passed, including the problem child one.If you are referring to the magnetometer, I'd note that they replaced the original magnetometer with a new, less sensitive one.How sensitive is it compared to Galileo or perhaps Juno?Let me start with some caveats, because it has been a few years since I paid close attention to this issue, and I'm no magnetosphere expert. So if you really want to know the facts, go research them (including looking at articles that came out at the time). So with those caveats applied, here goes:I think the instrument they are building now is probably more sensitive than previous instruments on earlier spacecraft. Technology advances, and Galileo is 40-year-old technology, and Juno is at least 15-year-old technology. That said, the current instrument for EC is less sensitive than the one they were trying to build. During reviews several years ago (again, you can look that all up) they determined that the instrument they had originally selected could not be made to work properly. It wasn't simply a case of throwing a lot more money at it, it just was not going to work, so they had to replace it with a new instrument that was do-able. (There was some really sensitive politics around that decision, because NASA was firing the only female instrument PI on the program, so there were allegations of sexism that NASA had to navigate. I think they did that successfully.)The bigger question, however, is if the instrument they are building now is sufficient to do the necessary science. I think there was some question about that. But if you asked ten scientists, you might not get a consensus one way or the other. Lots of times missions select instruments to do specific science, but then design compromises have to be made that impacts the science, and some people are unhappy with those compromises. That's apparently common to big flagship missions. You're not going to make everybody happy. I've heard grumblings about missions like Parker Solar Probe, as an example. But I think you'd have to be a scientist who was deep into the specifics of these missions to understand the issues. We mere mortals will find it impossible.Addendum: Let me add one thing that somebody can correct me on (they can look up the science requirements). I think that the issue of the magnetometer sensitivity is connected to how thick the Europa ice is. A more sensitive instrument will provide a better indication of how thick the ice is and that is important for understanding a lot of other things, like the water circulation under the ice and whether the water is touching rocks (and minerals) at the bottom, or a bottom ice layer--naturally, we would prefer that the water is touching minerals rather than circulating between two ice layers. The less sensitive instrument that they are flying apparently has a much larger error margin for determining the ice thickness. I think that is the issue for some people being disappointed with the instrument. But there really was no alternative, since the more sensitive instrument could not be made to work.But I may have that wrong and somebody can correct me.
Blackstar, what you wrote concurs with what I remember, and I'll add a bit from memory. I believe that a key requirement for the magnetometer is calibration (presumably so that the signal from the induced magnetosphere from the salty ocean can be distinguished within the incredibly strong Jovian field). The original cutting edge magnetometer could apparently deal with this through new technology that didn't work out (I believe that's why the instrument was dropped). There were several slides in a Clipper presentation from a while back that discussed how a new plan to roll the spacecraft (apparently a very complex maneuver) between Europa encounters would allow the needed calibration to provide the sensitivity required.
I was there when we came up with the "absurd" cost estimate. And here we are.
