New Horizons Design Reuse? Options

[Mariner9]

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.

[Guest_AlexBlackwell_*]

Mariner9, I don't know if this helps but a previous post of mine has an instructive reference. As Mike knows, there have been endless exchanges over the years regarding the Mars MCO/MPL/DS2 losses and issues surrounding F/B/C.

[gndonald]

On the other hand, Pioneer 10 and 11 had the Pioneer more for polital reasons than actual design lineage to Pioneers 6-9. It was felt at the time that calling the Jupiter mission "Pioneer" it would look more like a continuation of an existing program at Ames than an entirely new mission. It was true that AMES had a lot of experience building spin stabalized spacecraft, but there wasn't a lot of common hardware between the Solar Probes and the Jupiter missions.

The US Navy used to do the same sort of thing during the period between the Civil War and the Spanish-American war. Because Congress would not fund new ship construction, the Navy would request funds to 'repair' an old ship and then use the funds to build a new ship with the same name as the old one.

While I've linked to this before the Pioneer Orbiter Report, is very relevant to this discussion, as it shows that at the time, Ames was actively pushing the use of an 'up-rated' version of the Pioneer bus for use in outer planet operations such as orbiters and probe entry missions (On page 75 of the PDF mention is made of a plan for a Saturn Flyby/Uranus Probe Entry mission.)

[Jim from NSF.com]

There's almost no commonality between MGS and MCO/Odyssey; the former was built with Mars Observer spares.

Instruments team members are not the same as spacecraft team members. There is some spacecraft commonality between the two group

[nprev]

Interesting discussion.

So, it seems that there is in fact some "heritage" between missions, and that's cool....sure looks like there was a lot of ad hoc scrambling going on in response to unexpected events like the MO, MCO, and MPL failures, and that's what I was hoping to avoid with this idea.

The central thesis was that a common bus is a desirable thing for cost conservation and rapid response capability. Would new root designs for specific mission types with an anticipated lifetime of 20 years and production runs of, say, ten units be beneficial?

[mcaplinger]

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.

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.

[Mariner9]

Hmmm. This "debate" got way out of hand. It seems like I was being too general in stating that MGS, MCO, and Odyessey shared a common design, and you were being too general implying that MGS was built from spares of Observer (and little else) and that MCO and Odyessy had nothing in common with MGS.


Goes to prove the old saying: There are no good generalities. Including this one.