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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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dvandorn
post Sep 22 2006, 05:19 PM
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IIRC, spacecraft from Mariners 6 through 10, and through to Pioneers 10 & 11 and Voyagers 1 & 2, used the same basic octagonal spacecraft bus as the "starting point" for their development. Yes, each iteration went through a great deal of redesign and change based on the given missions, but I seem to recall that each one started out with the same sized-and-shaped bus unit...

Please, someone verify this old man's fading memory...? blink.gif smile.gif

-the other Doug


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Mariner9
post Sep 22 2006, 05:23 PM
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I'll start by saying I think your idea has some meritous points. I don't know about making 20 of the things, but there are some advantages to reusing the design.

Alas, that has already been proposed and rejected. The APL team pushed for a New Horizons 2, to be built almost exactly identical to the first vehicle (instruments included) and send it on a trajectory to one of the largest Kuiper Belt objects and do a flyby of Uranus on the way.

They pushed the mission mainly on 3 points:
- NH 1 will only see Pluto, and possibly one more random "Kuiper object of opportunity" in it's mission. By flying NH 2 you could be sure of seeing another few specific high interest targets.
- Uranus has been visited only once. Here is a chance for a flyby with modern instrumentation
- It would only cost half as much as NH 1.

Congress directed that a study be made on the proposal. The study's conculsions (many disputed by APL) was that the cost would actually be more like 70-80% the cost of NH 1 (I don't remember the number). Their point was that all you saved in building a copy was the initial design cycles. All the hardware would have to be procured again, and assembled, tested, and launched. None of those phases are cheap, and in fact represent a very high percentage cost of a mission. Additionally, the mission was propsed for 2008, and frankly their isn't a lot of plutonium available to put into an RPG right now. And there were other higher priority missions and programs competing for the funds, to fly missions to places that we already had been and wanted to do a follow up. The Kuiper belt hadn't been seen yet, so many people advocated waiting for NH 1 results before planning a follow up. Plus, with a short lead time (aka... start spending money NOW) it was a near impossibility that NASA could find the money lying around someplace.


So.... politically the idea might be dead. But even so, I myself expect to see at least one New Fronteirs #3 proposal from APL suggesting a re-use of the NH 1 design for some other outer solar system mission. The basic design seems like it lends itself nicely to a Neptune flyby (with probe?), or a Jupiter orbiter (with suitable propulsion module). There may be no practical way to fly the proposed NH 2 for the 350 million they claimed, but New Frontiers #3 will have a budget somewhere over 700 million. And with a likely launch date someplace around 2015-2016, the plutonium problem has the possibility of being solved.

Now... if I could just wish for it, I would love to see a program adopted using several copies of the NH 1 design for a series of outer planets missions, launched every 2 years. Sadly, I didn't get a pony for my 5th birthday, and I don't think I'm likely to get this wish either... but still, it's nice to dream about it.
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tasp
post Sep 22 2006, 05:25 PM
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The early Mariners and the Ranger probes had quite a bit of commonality.
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Mariner9
post Sep 22 2006, 05:29 PM
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Mariner 4, 6,7, and 9 had a very similar bus, and was in a real sense a design evolution.
The Viking 1 and 2 carried on this design.

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.


Mariner Jupiter-Saturn (the original name of Voyager) did much the same thing. It was sold partially by using the argument: Hey, same name, same orthagonal bus, it's just a follow on to Mariner.... and not in the same league as that expensive TOPS mission that Nixon just canned.
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nprev
post Sep 22 2006, 05:37 PM
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QUOTE (tasp @ Sep 22 2006, 10:25 AM) *
The early Mariners and the Ranger probes had quite a bit of commonality.


Yeah, and I'm trying to figure out why we ever got away from that...seems intuitively sensible. I'm sure that the Lunar Orbiters & Surveyors were all pretty much similar as well. Of course, these series all had a REALLY high operational tempo in comparision to the current era, and I'm sure that standardization was largely driven by schedule and reliability issues. Most interplanetary probes were launched in pairs (or more, in the case of the Soviet Mars campaign) in the hopes that at least one spacecraft would survive & perform.

Nevertheless, the lesson should have been learned...why not establish a standard platform for specific mission classes? We gotta do this cheaper in order to survive the coming budget crunches, and this seems like a good way to get that dynamic going again.


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mcaplinger
post Sep 22 2006, 05:43 PM
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QUOTE (nprev @ Sep 22 2006, 10:04 AM) *
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.

This idea surfaces every few months. Unfortunately, unless you are flying very similar missions and payloads and builidng a fair number of spacecraft (at least 5 or 10, at a guess) there are few economies of scale the way spacecraft are typically built. (You have to get into dozens or hundreds before they really kick in; Motorola did some interesting things for the Iridium constellation, for example.) Design commonaliity is usually at the box or subsystem level; there is little savings to be had for spacecraft structure, since structure is fairly easy to redesign. For example, there's a lot of commonality between Mars Odyssey, Stardust, and Genesis, even though they are pretty different missions.

And you'll forgive me for being opposed to give APL and the NH team a monopoly on building hardware to explore the outer solar system, much as I'm sure they would like that.


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centsworth_II
post Sep 22 2006, 05:43 PM
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QUOTE (Mariner9 @ Sep 22 2006, 01:23 PM) *
... isn't a lot of plutonium available to put into an RPG right now.


As I recall, it looked iffy until near the end that NH1 would get a full tank. Imagine trying to get enough for a fleet of NH craft! You could propose a different power supply but that would already be a MAJOR design change and lead to a whole different craft.
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Jim from NSF.com
post Sep 22 2006, 07:15 PM
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NH was good only for this mission. It was a point solution. Using the spinning solid motor comprises the design. LRO and MRO benefit from using the 3-axis Centaur. There are better buses out there
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tedstryk
post Sep 22 2006, 09:21 PM
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QUOTE (Jim from NSF.com @ Sep 22 2006, 07:15 PM) *
NH was good only for this mission. It was a point solution. Using the spinning solid motor comprises the design. LRO and MRO benefit from using the 3-axis Centaur. There are better buses out there



The NH2 idea, which would have flown by Uranus during equinox, would have been well suited to the design, because it was a flyby and speed and simplicity were important. If there is an engineering model or something (and I don't think there is) that could be flight readied for a fly by Uranus or Neptune and one or more of these new KBOs, I would be for it. But I think it would be better to design something new than recreate NH, although there may be some heritage. NH was affected by the need to get to Pluto in a hurry before the possible freezing out of the atmosphere for ~200 years and the loss of more territory to darkness as it moves away from its 1980s equinox. It is the only mission I can think of in which haste was so much of a factor.


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Mariner9
post Sep 22 2006, 09:31 PM
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I'm not sure why we all forgot this one, but Mars Global Surveyor, Climate Orbiter, and Odyssey are very similar spacecraft. What makes the design appear different at first glance is the move from twin solar panels to a single panel between MGS and Climate Orbiter.

The same thing was true for Polar Lander, and Mars 2001 lander (now the Phoenix).

The problem was that certain people at the top (I won't mention Dan Goldin by name) thought that you could restrict the cost just a bit too much by re-using existing designs. So Mars 98 was a complete failure.

The design of Climate Orbiter didn't kill it (the hardware was very similar to MGS), but long hours, stretching personell between both missions, and lack of strict protocol did. The complete redesign of the Pathfinder into Polar Lander was insane even on the face of it, so even if the software glitch on the landing sensors hadn't killed it, it would have been sheer luck if nothing else did.
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Guest_AlexBlackwell_*
post Sep 22 2006, 09:36 PM
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QUOTE (Mariner9 @ Sep 22 2006, 11:31 AM) *
The complete redesign of the Pathfinder into Polar Lander was insane even on the face of it...

[Mars] Pathfinder to [Mars] Polar Lander? The former was built in house at JPL; the latter by LMA. I guess I'm not following you.
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mcaplinger
post Sep 22 2006, 10:11 PM
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QUOTE (Mariner9 @ Sep 22 2006, 02:31 PM) *
I'm not sure why we all forgot this one, but Mars Global Surveyor, Climate Orbiter, and Odyssey are very similar spacecraft.

There's almost no commonality between MGS and MCO/Odyssey; the former was built with Mars Observer spares.
QUOTE
The problem was that certain people at the top (I won't mention Dan Goldin by name) thought that you could restrict the cost just a bit too much by re-using existing designs. So Mars 98 was a complete failure.

Since there was no commonality between MGS and MCO, this could hardly have been a cause. I don't think we need to debate, again, why MCO failed; that story is fairly well documented and doesn't have much to do with better-faster-cheaper in my opinion.


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Mariner9
post Sep 22 2006, 10:49 PM
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Polar Lander and Pathfinder had some connections, although more obscure. The plan was to re-use the Aeroshell, cruise stage, and anything else they possibly could. My point in mentioning it at all was that when Pathfinder was accomplished for about 275 million, Dan Goldin pushed for an even lower budget on Polar Lander. If Polar Lander really had been signifigantly based on the Pathfinder design that might have been at least somewhat reasonable, but it ended up having very little in common with Pathfinder.

At least the designs of Mars 98 lander and 2001 Lander were nearly identical, but by that time it was too late... 98 failed miserably and 2001 was put in storage (to be reborn under the Mars Scout program).


As for mcaplinger's points, I couldn't disagree more. MGS was built with Mars Observer spares? I don't think that is precisely correct. If you even glance at a diagram of the two vehicles, you will see that MGS and Mars Observer don't even look remotely similar.

The spares you are reffering to are the instruments (a major investment to be sure). NASA wanted to refly as many instruments as soon as possible, so the Gamma Ray Spectrometer (very heavy) was flown on Odyssey, and the Atmospheric sounder was flown on Climate Orbiter. The rest were put on an entirely new spacecraft bus and design, avoiding the re-use of an Earth orbital design that Observer had used.


And the failure of MCO has nothing to do with the debate over Faster-Better-Cheaper????? It was the failure of MCO, followed by Polar Lander, that caused a lot of internal debate and review of the entire Faster Better Cheaper implementation at NASA. I would say they are VERY connected.
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mcaplinger
post Sep 22 2006, 11:43 PM
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QUOTE (Mariner9 @ Sep 22 2006, 03:49 PM) *
The spares you are reffering to are the instruments (a major investment to be sure).

Every electronics box in the MGS spacecraft, with the single exception of the solid-state recorder, is a Mars Observer spare.

If we're going to have an argument, perhaps you could state your qualifications. I worked on one of the instrument teams for each of Mars Observer, MGS, MCO, MPL, Odyssey, Phoenix, and MRO.


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