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New Horizons Design Reuse?
nprev
post Sep 22 2006, 05:04 PM
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Hopefully this thread is located in the right place...if not, my apologies, Doug.

It occurs to me that one of the fundamental problems with UMSF from a funding/project management perspective is that each spacecraft is usually unique, which pretty much zaps any savings that might be realized via economies of scale. It would sure be nice to drive down costs & fly more missions.

Of course, each spacecraft usually HAS to be a little--or a lot--different in terms of payload in order to answer the investigative questions that justify the mission. However, why don't we at least standardize the spacecraft bus for specific classes of missions? For example, the NH design should prove to be an extremely robust outer system platform for flyby/orbital operations anywhere at or beyond the orbit of Jupiter.

If we could produce, say, twenty NH busses for use over the next twenty years or so, then the payload design would be driven in part by a fixed set of interfaces, thus simplifying systems engineering considerably, decreasing lead-time, and therefore enabling far better long-term mission planning. Also, we could always go to Congress during hard times & say something like "we built all these NH clones...it would be a shame not to use them" (an old DoD trick)...and then we'd have orbiters for all four of the gas giants, plus lots of other cool things.... wink.gif

This sort of schema would also provide a rapid-response capability for new discoveries or unique events. For example, let's say that another comet like Shoemaker-Levy 9 was found that was gonna crash into Saturn or pass through its ring system in about ten years. A standard outer-planet bus could conceivably allow us to fly a mission on short notice, provided that other circumstances like launch window/trajectory availability are favorable.


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Mariner9
post Sep 23 2006, 01:12 AM
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Ok, a comparatively rare moment for me (being humble). From the various articles I read over the years I was under the impression that the MGS design was not only a new physical bus, but the guts were a new design as well: entirely new communcations, propulsion, etc etc, except for the instruments.

Clearly you've got far better credentials than I do since my knowledge comes as a hobby, not from working on these projects.

So, I'll admit defeat on the Mars Observer vs. MGS designs. I was obviously wrong. In fact, I'm quite interested to learn this, since it was very different from my previous understanding.

But confused how I got this impression. I've read a number of references to MCO and Odyssey having a common design to MGS in order to avoid the necesity to redesign every vehicle from scratch, and thus save money, and increase the chance of sucess. The whole vision of Mars Surveyor program back in 96-97 time period seemed to revolve around this (to hear magazines like Aviation Week tell it). The MGS, MCO and Odyssey physical bus sure look alike... although I'll grant you that doesn't say much about what is in the internal electronics.

Were those articles (mostly from the general press, but also in different books I've read) completely wrong about this? Was the public (or Congress, or higher-ups) being fed a line in order to make people think there was a commonality to the vehicles that wasn't really there? Was this coming from reporters and writers who really 'didn't get it" and were over simplifying things?

Sounds like you were "on the scene" so to speak. I'd be interested to know your take on that. (seriously)


So... humble part is over. I'm having much more trouble accepting the idea that the loss of Mars 98 (both Polar Lander and MCO) had very little effect on Faster-Better-Cheaper. After those missions were lost there was much said about rethinking the Faster-Better-Cheaper mantra, not only on the Mars missions but on the other planetary missions as well. And certainly it would be impossible to imagine anyone seriously (or at least publically) talking about a 1.5 billion dollar rover mission (MSL) back in the days before 1999. The management of NASA wasn't allowing such things to be spoken from what I could see.
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mcaplinger
post Sep 23 2006, 07:23 PM
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QUOTE (Mariner9 @ Sep 22 2006, 06:12 PM) *
But confused how I got this impression. I've read a number of references to MCO and Odyssey having a common design to MGS in order to avoid the necesity to redesign every vehicle from scratch...

Well, I don't recall having read anything like that, so I can't really speak to your impression. Certainly Odyssey is a lot like MCO, and MRO is clearly a direct evolution from MCO. And there is some commonality between MGS and MCO, since Lockheed-Martin in Denver did the structure and propulsion for both. But as far as the avionics goes, very little commonality. See, for example, http://www2.jpl.nasa.gov/files//misc/m96pkt.pdf -- "To minimize costs, most of the spacecraft’s electronics and science instruments are spare units left over from the Mars Observer mission. The spacecraft design also incorporates new hardware — the radio transmitters, solid state recorders, propulsion system and composite material bus structure."

There is always a tendency to oversell heritage and commonality, but the engineering reality is often far different.
QUOTE
I'm having much more trouble accepting the idea that the loss of Mars 98 (both Polar Lander and MCO) had very little effect on Faster-Better-Cheaper.

It certainly had a lot of effect on FBC, but were the losses caused by FBC? The MCO loss could have been prevented with the right 5 minutes of extra engineering time. Anyone who tells you there is a simple, direct relationship between mission cost and the probability of success is oversimplifying the problem -- how much extra money would you have had to spend for that 5 extra right minutes to happen? If spending more money was a guarantee, we wouldn't see big mistakes on costly programs like Galileo and HST. Published accounts by the people at LMA involved in MS98 (see http://klabs.org/richcontent/MAPLDCon02/pr..._a/a0_euler.pdf and http://brain.cs.uiuc.edu/integration/AAS01_MCO_MPL_final.pdf ) suggest that fairly modest increases in mission cost (on order of 30%) would have been enough. I think the pendulum on cost versus risk has swung way too far in the direction of cost.


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- nprev   New Horizons Design Reuse?   Sep 22 2006, 05:04 PM
- - dvandorn   IIRC, spacecraft from Mariners 6 through 10, and t...   Sep 22 2006, 05:19 PM
- - Mariner9   I'll start by saying I think your idea has som...   Sep 22 2006, 05:23 PM
|- - centsworth_II   QUOTE (Mariner9 @ Sep 22 2006, 01:23 PM) ...   Sep 22 2006, 05:43 PM
- - tasp   The early Mariners and the Ranger probes had quite...   Sep 22 2006, 05:25 PM
|- - nprev   QUOTE (tasp @ Sep 22 2006, 10:25 AM) The ...   Sep 22 2006, 05:37 PM
- - Mariner9   Mariner 4, 6,7, and 9 had a very similar bus, and ...   Sep 22 2006, 05:29 PM
|- - gndonald   QUOTE (Mariner9 @ Sep 23 2006, 01:29 AM) ...   Sep 23 2006, 01:25 AM
- - mcaplinger   QUOTE (nprev @ Sep 22 2006, 10:04 AM) It ...   Sep 22 2006, 05:43 PM
- - Jim from NSF.com   NH was good only for this mission. It was a point...   Sep 22 2006, 07:15 PM
|- - tedstryk   QUOTE (Jim from NSF.com @ Sep 22 2006, 07...   Sep 22 2006, 09:21 PM
- - Mariner9   I'm not sure why we all forgot this one, but M...   Sep 22 2006, 09:31 PM
|- - AlexBlackwell   QUOTE (Mariner9 @ Sep 22 2006, 11:31 AM) ...   Sep 22 2006, 09:36 PM
|- - mcaplinger   QUOTE (Mariner9 @ Sep 22 2006, 02:31 PM) ...   Sep 22 2006, 10:11 PM
|- - Jim from NSF.com   QUOTE (mcaplinger @ Sep 22 2006, 06:11 PM...   Sep 23 2006, 02:13 PM
- - Mariner9   Polar Lander and Pathfinder had some connections, ...   Sep 22 2006, 10:49 PM
|- - mcaplinger   QUOTE (Mariner9 @ Sep 22 2006, 03:49 PM) ...   Sep 22 2006, 11:43 PM
- - Mariner9   Ok, a comparatively rare moment for me (being humb...   Sep 23 2006, 01:12 AM
|- - mcaplinger   QUOTE (Mariner9 @ Sep 22 2006, 06:12 PM) ...   Sep 23 2006, 07:23 PM
- - AlexBlackwell   Mariner9, I don't know if this helps but a pre...   Sep 23 2006, 01:22 AM
- - nprev   Interesting discussion. So, it seems that there i...   Sep 23 2006, 04:51 PM
- - Mariner9   Hmmm. This "debate" got way out of han...   Sep 23 2006, 11:37 PM


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