Author Topic: NASA Evolvable Mars Campaign Study: June 23, 2014 Presentation to the NAC  (Read 56882 times)

Offline yg1968

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Here is a very interesting presentation on the evolvable Mars campaign study which was given at the June 23, 2014 NAC meeting:
http://www.nasa.gov/sites/default/files/files/20140623-Crusan-NAC-Final.pdf
« Last Edit: 07/05/2014 04:46 pm by yg1968 »

Offline Coastal Ron

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Less detail than the Boeing study recently released through FISO - discussion here:

http://forum.nasaspaceflight.com/index.php?topic=35115.0

Even though they talk about being affordable, that's impossible to know without a true commitment from Congress and the President.  Plus they assume the SLS, which at this point is still an unknown risk and a huge cost driver.

I'm not sure if this study changes anything...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Eric Hedman

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The first of the six principles is the key: "Implementable in the near-term with the buying power of current budgets and in the longer term with budgets commensurate with economic growth"

Does anybody believe that in the current political environment that NASA's budget will grow along with growth in GDP?  If that's what NASA's counting on I can only assume "Houston, we have a problem."  This growth won't happen unless something changes the mindset in D.C.

Offline Proponent

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Does anybody believe that in the current political environment that NASA's budget will grow along with growth in GDP?

I can't speak for others, but I don't.

Offline yg1968

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That is why I think that the focus on a L2 or DRO gateway is essential. If it turns out that we don't have enough money for Mars, the L2 Gateway is a good fall back destination. Furthermore, it should be easier to form international and commercial partnerships for a L2 or DRO gateway.

Offline Coastal Ron

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That is why I think that the focus on a L2 or DRO gateway is essential. If it turns out that we don't have enough money for Mars, the L2 Gateway is a good fall back destination.

I think an L2 station will be an important research opportunity, and the basis for future expansion into a transportation node or mission assembly point.  And I think it's the next logical destination for the space exploration world.

But unless it is recognized as being absolutely essential, and not just a fallback choice, I don't think it will get funded.  We just don't have the money or political will to sustain 2nd choices.

Quote
Furthermore, it should be easier to form international and commercial partnerships for a L2 or DRO gateway.

I don't see how NASA can do an L2 station on it's own in the current budget environment, and NASA has recently stated that the ISS is the last space station that they will own.  It remains to be seen if that stays true, but that pretty much means that future large projects in space will have to be partnerships in order to spread the financial pain.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline yg1968

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That is why I think that the focus on a L2 or DRO gateway is essential. If it turns out that we don't have enough money for Mars, the L2 Gateway is a good fall back destination.

But unless it is recognized as being absolutely essential, and not just a fallback choice, I don't think it will get funded.  We just don't have the money or political will to sustain 2nd choices.

It's not essential for Mars. It's essential because it is the next logical step in exploration. Furthermore, it's also a middle ground for those that would prefer that we first land on the Moon prior to going to Mars.

Offline KelvinZero

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That is why I think that the focus on a L2 or DRO gateway is essential. If it turns out that we don't have enough money for Mars, the L2 Gateway is a good fall back destination.

But unless it is recognized as being absolutely essential, and not just a fallback choice, I don't think it will get funded.  We just don't have the money or political will to sustain 2nd choices.

It's not essential for Mars. It's essential because it is the next logical step in exploration. Furthermore, it's also a middle ground for those that would prefer that we first land on the Moon prior to going to Mars.
I think we would pretty much be talking about a DSH module which I think should also be the basis for the Mars habitat Unit from Mars Direct. Moving it to L2 is just a detail, for example I have seen examples from some Boeing proposal where it is moved from L2 to lunar orbit for specific missions. I think this keeps popping up as the one critical unit in any plan, assuming we make it a requirement to not have to go back to the drawing board to adapt it from zero-g to Mars or the Moon.

I very much want to see something like this attached to the ISS, and perhaps later being moved around unmanned with that 40Kw SEP tug, eg to L2 or LLO attached to that captured asteroid, or even spin it up for centrifugal experiments. But I think by far the most important thing is just to get it up there and accruing a history of reliability.
« Last Edit: 07/08/2014 11:33 am by KelvinZero »

Offline yg1968

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The strange thing about this study (and the Boeing proposal) is that it leaves very little room for commercial partnerships. The only option for commercial companies is that there seems to be some pre-mission assembly of the crew/transit hab and some post-mission refurbishment of the habitats that is required at the HEO/DRO staging point. Presumably the asssembly and refurbishment could be done by commercial companies.
« Last Edit: 07/10/2014 08:30 pm by yg1968 »

Offline yg1968

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See slides 9-12, 27 and 34 of this July 28 NAC presentation for an update on the Evolvable Mars Campaign:
http://www.nasa.gov/sites/default/files/files/20140728-Williams-NAC.pdf

See also the white paper on Pioneering space which was released on May 29 2014:
http://www.nasa.gov/sites/default/files/files/Pioneering-space-final-052914b.pdf
« Last Edit: 08/14/2014 05:16 pm by yg1968 »

Offline RonM

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The strange thing about this study (and the Boeing proposal) is that it leaves very little room for commercial partnerships. The only option for commercial companies is that there seems to be some pre-mission assembly of the crew/transit hab and some post-mission refurbishment of the habitats that is required at the HEO/DRO staging point. Presumably the asssembly and refurbishment could be done by commercial companies.

That's not surprising, NASA is basing everything on SLS and Boeing is the prime contractor for SLS.

With international support and big commercial rockets in the near future, NASA can always change the plan to take advantage of these commercial services. But that depends on Congress and where they want the money spent.

Offline yg1968

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The strange thing about this study (and the Boeing proposal) is that it leaves very little room for commercial partnerships. The only option for commercial companies is that there seems to be some pre-mission assembly of the crew/transit hab and some post-mission refurbishment of the habitats that is required at the HEO/DRO staging point. Presumably the asssembly and refurbishment could be done by commercial companies.

That's not surprising, NASA is basing everything on SLS and Boeing is the prime contractor for SLS.

With international support and big commercial rockets in the near future, NASA can always change the plan to take advantage of these commercial services. But that depends on Congress and where they want the money spent.

On this topic, it seems that there is some room for commercial partnerships for lunar or cislunar missions. From the Pionneering space white paper:

Quote from: page 7
The path to Mars runs through cis-lunar space and we can exploit the beneficial features of this region in a relatively low-risk environment. We also can benefit from international and commercial partnerships to prepare our hardware and gain experience for human missions beyond and on to Mars. High Earth orbits, the DRO around the Moon to which EM-1 and EM-2 will fly, and the Earth-Moon Lagrange points are all orbital locations in which deep space systems can be tested and operational procedures validated while still close enough to Earth to safely recover systems in the event of problems. Cis-lunar space is ideal for the advancement of deep space systems such as human deep space habitation.

Quote from: page 9
Various international partners are interested in both robotic and human missions to the lunar surface, and NASA will likely go with them in some way. U.S. commercial entities also have interest in robotic lunar missions through NASA’s Lunar CATALYST program, which aims at enabling commercial provision of lunar landing services. NASA exploring the possibility of utilizing one of these commercial landers to place a Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) payload onto the lunar surface later this decade, an early test of ISRU with lunar regolith.  Consistent with the GER, a web of international, NASA and commercial partnerships will yield both robotic and crewed spacecraft around and on the Moon. Additionally, many of our international partners want to send humans to the lunar surface. NASA may participate at some level, as the lunar surface affords some benefit in partial Earth-gravity operations. But NASA’s human spaceflight focus is on advancing technologies and operational experience in long-duration missions in the cis-lunar proving ground, using DRO missions, on the path that leads to Mars.

Quote from: page 13
We also are laying the foundation for partnerships with both other nations and the US commercial sector. This will be an evolving roadmap; we will fill in more detail—and some major pieces—in the months and years to come as options and partnerships materialize and mature.

http://www.nasa.gov/sites/default/files/files/Pioneering-space-final-052914b.pdf
« Last Edit: 08/14/2014 05:19 pm by yg1968 »

Offline yg1968

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This part of the Pioneering report is also interesting:

Quote from: page 9
Mars-class missions will require crew life support for many hundreds of days at a minimum; a deep space habitation capability (hab) is critical for mission success. It is essential that the hab design receive thorough testing in a relevant deep space microgravity and high radiation environment—well before a final design and committing a crew on a Mars mission. The first deep space hab could be provided by a commercial or international partner, and could provide additional resources including power, EVA suits, stowage, science instruments, and advanced life support testing for Mars class missions as well as extend the in-space time of crewed Orion missions. The hab element also could facilitate additional docking ports to open the cis-lunar space to commercial and international missions in concert with or in addition to the Orion flights. In keeping with our space infrastructure reuse principle, a deep space hab also could provide a dual purpose, in addition to proving systems for Mars missions, by potentially serving as a staging point for lunar surface robotic science or human missions sought by our international partners. Based on the early results of orbital mechanics studies, the cis-lunar proving ground is a favorable location to test and develop the Mars class spacecraft systems prior to sending humans to pioneer Mars.

Quote from: page 13
Exploration Augmentation Module Partnership: NASA is investigating concepts for deep space habitation module systems development. The deep space habitation module itself is likely to be provided by a commercial or international partner—or some hybrid of these.

http://www.nasa.gov/sites/default/files/files/Pioneering-space-final-052914b.pdf
« Last Edit: 08/16/2014 02:14 pm by yg1968 »

Offline mike robel

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What do you see as the role for commercial partnerships?

They could, if we follow the ISS resupply paradigm, deliver the provisions to stock the craft with consumables.  This seems to have even less ROI for a supplier than ISS, because it is not like these ships will be leaving every three months, more like ever 26 months.  Of course, several could be undergoing orbital construction at the same time.  (Assuming construction is more like docking several modules together and not doing actual construction in space.)  And I am curious if direct throw of components to Mars would be as effective, though perhaps not as efficient, as some other method.  Never mind being elegant.

If they build a part of the spacecraft, then it is really no different than NASA doing business with people now.  If it is an integral part of the spacecraft, I should think there would be much more NASA oversight, design, and so forth than for something that only temporarily docks with the Mars Spacecraft, such as supply deliverables.

I am sure there are a multitude of other facts and assumptions I am leaving out.

Offline Coastal Ron

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What do you see as the role for commercial partnerships?

They could, if we follow the ISS resupply paradigm, deliver the provisions to stock the craft with consumables.  This seems to have even less ROI for a supplier than ISS, because it is not like these ships will be leaving every three months, more like ever 26 months.

Quote
Of course, several could be undergoing orbital construction at the same time.  (Assuming construction is more like docking several modules together and not doing actual construction in space.)

Our current mode of construction assumes that transportation is a limitation, so we try to maximize how much we pack into construction elements.  If transportation were inexpensive and available then I think we would transition to a mode of construction that more resembles what we do here on Earth - build a shell, and then fill it up and finish it onsite.

With current designs of space construction that would likely mean shipping construction modules (inflatable or rigid) ready to be filled up.  We did that somewhat on the ISS where the Shuttle would bring up ISPR's and other equipment to be installed.  That also maximizes the sizes of modules that can be lifted.

And just as building contractors don't own the trucks they use to bring construction material, the private sector would be used to transport material as well as doing resupply and crew (construction, test, outfitting, and operations) transportation.

There is a role for the private sector.  However just based on the level of dysfunction our politicians have regarding space, the likelihood of this happening in the next decade is very low.

Quote
If they build a part of the spacecraft, then it is really no different than NASA doing business with people now.  If it is an integral part of the spacecraft, I should think there would be much more NASA oversight, design, and so forth than for something that only temporarily docks with the Mars Spacecraft, such as supply deliverables.

At some point we need to create international standards that everyone can use, not just "NASA" standards.  I hope Commercial Crew is the last transportation system that NASA has primary oversight into, since I think our aerospace industry is more than capable of designing and building quality spacecraft without NASA oversight.  NASA can and should be a resource, just as it was in it's NACA days, but thats it.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline sdsds

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What do you see as the role for commercial partnerships?

They could, if we follow the ISS resupply paradigm, deliver the provisions to stock the craft with consumables.
 

I do sense this is how NASA sees the potential role of commercial partners in their "Evolvable Mars" future.

This seems to have even less ROI for a supplier than ISS, because it is not like these ships will be leaving every three months, more like ever 26 months.

I think NASA is implying (see attached image extracted from the Williams NAC presentation) an extensive effort to resupply and even refurbish spacecraft in cislunar space. It doesn't get explicitly mentioned I think because it isn't envisioned as being carried out by NASA missions, but by partner missions.

Our current mode of construction assumes that transportation is a limitation, so we try to maximize how much we pack into construction elements.  If transportation were inexpensive and available then I think we would transition to a mode of construction that more resembles what we do here on Earth - build a shell, and then fill it up and finish it onsite.

With current designs of space construction that would likely mean shipping construction modules (inflatable or rigid) ready to be filled up.  We did that somewhat on the ISS where the Shuttle would bring up ISPR's and other equipment to be installed.

While it could (and perhaps should) go that way, it doesn't seem to be part of the future NASA envisions. An ISPR fits through a CBM hatch. Yet the approach of berthing cargo vehicles using a robotic arm, while "standard" today for ISS, does not seem to be getting any focus of attention as a technology which NASA will carry forward. Note instead the emphasis on the (smaller) international docking system hatch, which doesn't support delivery of ISPR-sized cargo.
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Offline A_M_Swallow

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The Cygnus has a CBM.  The Dragon comes in two versions one with a CBM and the second with international docking system (NDS).

The Mars Transfer Vehicle could consist of modules fastened together using a mixture of CBM and NDS docking ports.  NDS now allows for the docking of electrical and data connections.  With a bit of thought the cockpit can use the data links to send instructions to say the engines.

Robotic arms are now TRL 9 items.  A construction module could host several arms and suitports to simply EVA.

Offline sdsds

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[...] a mixture of CBM and NDS docking ports [...] a construction module could host several arms

I agree these could happen. I even think they probably should happen. I just don't see evidence NASA's "Evolvable Mars" planners agree with us!
« Last Edit: 08/17/2014 04:22 am by sdsds »
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Offline A_M_Swallow

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[...] a mixture of CBM and NDS docking ports [...] a construction module could host several arms

I agree these could happen. I even think they probably should happen. I just don't see evidence NASA's "Evolvable Mars" planners agree with us!

The suggestion has been made.  Give them time to think about it.

When you are short of time and money buying the simple stuff off the shelf permits you to concentrate on the difficult and interesting stuff.

Offline yg1968

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Interesting interview with astronaut Al Worden. It discusses the need for a gateway among other things:
http://www.americaspace.com/?p=72340

Offline gbaikie

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Interesting interview with astronaut Al Worden. It discusses the need for a gateway among other things:
http://www.americaspace.com/?p=72340

"...What are your thoughts on keeping a human presence in LEO on space stations, now and in the future?

Worden: Best idea yet. But I do see the ISS or something similar being used as a gas station for deep space probes. If we don’t use L5 [the fifth Lagrangian point, proposed as a location for possible space habitats], then a station in orbit will have to do."

And it linked to Earth/Sun L-points, it seems to me L-5 would be Earth/Moon L-5.  Or a Wiki says:
"The optimal habitat orbits are still debated, and so orbital stationkeeping is probably a commercial issue. The lunar L4 and L5 orbits are now thought to be too far away from the moon and Earth. A more modern proposal is to use a two-to-one resonance orbit that alternately has a close, low-energy (cheap) approach to the moon"

I say that lunar L4 and L5  are fine for large L-5 type colony, though not necessarily Earth/Sun L-4 or 5.
I would say the problem with Earth/Sun L-4 or 5 is you too far from any gravity well to use the the gravity well to change one's vector and/or use Oberth effect. Though both are less important if using low thrust, eg, ion type propulsion. And in terms of distance, lunar L4 and L5 are essentially in middle of everything- solar system destinations, Cislunar and Earth and Moon. Or any of Lunar points are in the middle of it.
The thing about lunar 4 or 5 is it's not a "saddle like" gravitational point. They are shallow gravitational bowls- or have slight gravitational tendency for things to end up at the exact point of the L-point.
Or the exact point is good place to put one large space habitat or "town".
So for millions of smallish objects, lunar L-1 or 2 would be fine- as it not so much about a point but rather a zone and it's bigger zone in terms volume than LEO.
And if going for one or few big "things" L-4 or 5 seems "better".
Another way to say it, is that L-1 and L-2 should be "international waters" type thing, and as should LEO
whereas L-4 and L-5 [and GEO] can be more like property to be owned. Or LEO and L-1 and 2 are in the middle of the freeway and L4/5 and GEO are the off ramps.
And since L-4 and L-5  are more suited to be owned/leased [or whatever], they will tend to encourage large investment dollars needed for big structures.

Also I don't agree with "There is no reason to go back to the Moon, unless we get serious and place a large telescope on the back side to see the rest of our galaxy."
There is a reason for government to explore the Moon to see if there is minable water.
And if there is minable lunar water, we could get a few large telescopes to look at rest galaxy and also a few telescopes that look at our solar system. In fact any large government type telescope on Earth becomes a relic of the days of when we weren't spacefaring. And kids will ask the teacher/parent why humans build such telescopes due to the obvious fact that they had to look thru Earth's atmosphere- "What was the point of it?", they will ask.

And a lot of other things, besides telescopes, will be done on the Moon- it's an endless list.
BUT if there is not minable lunar water [from which to make rocket fuel] then we aren't going to build any telescopes on the Moon- until such time as there is cheap rocket fuel available in space [from say, mining asteroids and/or launch cost from Earth is less than $100 per lb or rocket fuel in high Earth orbits is around $1000 per lb].

I also don't agree that there are no life-supporting planets in our solar system.
Mars could be life-supporting as can Venus- in the near term. And a "life-supporting planet" [earth replica] at alpha centauri  is not as life-supporting- even if, the star travel tickets [and any cargo] from L-1 to this planet's L-1 were free.
« Last Edit: 11/28/2014 11:57 pm by gbaikie »

Offline yg1968

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Gerst calls the Evolvable Mars Campaign Study (due to be finished this summer): "a plan for a plan":
http://spacenews.com/nasa-not-ready-to-update-mars-mission-architecture/

Offline yg1968

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Here is a recent presentation at the January NAC (HEO Committee) meeting:
http://www.nasa.gov/sites/default/files/files/2-20150112-NAC-Crusan-v6.pdf

See also this presentation by Gerst:
http://www.nasa.gov/sites/default/files/files/NAC_HEO_Gerst4final-1.pdf
« Last Edit: 01/28/2015 03:48 pm by yg1968 »

Offline redliox

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Here is a recent presentation at the January NAC (HEO Committee) meeting:
http://www.nasa.gov/sites/default/files/files/2-20150112-NAC-Crusan-v6.pdf

See also this presentation by Gerst:
http://www.nasa.gov/sites/default/files/files/NAC_HEO_Gerst4final-1.pdf

Thanks for the update!  Exciting to see something new related to the 'official' plans.
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Offline Robotbeat

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Did anyone catch this? Phobos base, leveraging stuff from Asteroid Redirect Option B.
Slide 21:
http://www.nasa.gov/sites/default/files/files/2-20150112-NAC-Crusan-v6.pdf
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Offline Galactic Penguin SST

FYI: I have moved some of the posts about the necessity of funding a NASA HSF mission to Mars to this new topic instead. Please leave this topic for discussion of the study itself. Thanks!
« Last Edit: 01/30/2015 03:19 am by Galactic Penguin SST »
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Offline Robotbeat

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I'm giving this a bump. I keep hearing talk about this "Evolvable Mars" thing. It's something that headquarters is apparently taking seriously.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline gbaikie

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Here is a recent presentation at the January NAC (HEO Committee) meeting:
http://www.nasa.gov/sites/default/files/files/2-20150112-NAC-Crusan-v6.pdf

See also this presentation by Gerst:
http://www.nasa.gov/sites/default/files/files/NAC_HEO_Gerst4final-1.pdf

The Gerstenmaier one is much better. Both reminds me of SOTU type speeches, by which I mean
more or less useless. But Gerstenmaier's is shorter, so big plus for that. It's also mentions the commercial
aspect more- another significant point to make. And discusses using the L-points.
If they replaces pioneer space, with focus on developing commercial markets in Space, that would be a good message. It's what the pioneers were doing- whether it developing a farmstead, trapping furs, or looking for gold. And such activity brought in the bankers, etc - and other whores.
Of course another aspect of pioneers was getting as far from governments as possible. Mars might be good for that, the moon not so good. So pioneers were also about adventure and freedom. But the pioneer as practical matter brought prosperity to the world, and a focus on government exploration to discover ways to start markets would something in US national interest and something US citizen's will financially support. Which brings to a bullet point of fist laundry list PDF:
--Define a program that is robust across election cycles and economic conditions--
The people who vote in election cycles have always and will always be interested in the economy, as in
"It's the economy, stupid!"
So if NASA explores the moon with purpose of determining if and where there minable lunar water, that is
related to "It's the economy, stupid". It's not trillions of dollar here and now, but it's about the future. And the future is also what election cycles are about. Of course it could trillions of dollars in the future, or trillions of dollars "for the children".
What is more important than commercial lunar water mining is a market for rocket fuel in Space. Lunar water miners will need for there to be a market for rocket fuel in space, but the Market of rocket fuel in space is bigger and more important than lunar water mining [and whether if even profitable to mine lunar water].
So to get a market of rocket fuel in orbit [as compared to lunar surface or Mars surface] NASA should delevep a operational depot. And it make the depots as simple as possible. So this even include rocket fuel which is non-cryogenic, though I favor getting to point of a depot for LOX, or don't think having depot for LOX is too much of an added complication. But room temperature storable rocket fuel would still be improvement over what we have, and it's possible that lunar miners could just ship lunar water to lunar orbit, rather than LOX and LH2. Or by just have operational depot for any kind rocket fuel transferred to spacecraft, a step forward to transferring cryogenic rocket fuel.
Another thing is once one has a more free market of rocket fuel in space, then private enterpise generally doesn't want to store it's products for a long duration of time. Or the higher percentage of the bought rocket fuel could mostly stored for days rather than months. Anyways, NASA should go in direction of not owning network of depots, but rather want a competitive market which is able to delivery rocket fuel where ever and whenever NASA needs it. And that NASA would only be a customer, not the sole or main customer. But NASA should own or be a in "partnership" with first operational depot. And it should be in LEO and should consider as an asset of a spaceport [be at the correct inclination for the launches from the spaceport].

« Last Edit: 03/24/2015 02:04 am by gbaikie »

Offline sdsds

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Eagerly awaiting word on the formal presentation of this study. Is it still on track for "this summer?" Is there an official public release date? Is there a hint or rumor about it? Or has it 'gone dark?'
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Offline redliox

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Apparently not.

This is summary of Evolvable Mars Campaign (EMC ).[...]

http://spirit.as.utexas.edu/~fiso/telecon/Craig_6-10-15/

The presentation has some promise, although it's spoken in the near-constant 'aloofness' NASA seems to major in.  There seems to be a lot of talk about electric propulsion and the sizing of the habitats for deep space, Phobos, and Mars with hopes in making the habs possess commonality.  The next thing that caught my attention was the flow chart of sizing landers and how to relate them to varying degrees of ISRU.

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Offline Oli

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There are 2 recent papers on SEP/Chemical respectively Hybrid which I think are very interesting. Maybe we can discuss them here.


Mars Conjunction Crewed Missions with a Reusable Hybrid Architecture by NASA Langley, JPL et al.

Combining Solar Electric Propulsion and Chemical Propulsion for Crewed Missions to Mars by NASA et al.


Both are attached.

Offline Impaler

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Interesting, the Hybrid approach uses chemical propulsion only in the vicinity of Mars for capture and escape.  I suspect that simply increasing the SEP systems mass and propellent would do these same maneuvers and replace the chemical propulsion entirely while being lower in total mass.  But it would likely take longer to complete the maneuvers as they look to be making very efficient use of the Chemical propulsion where it is used.  Alternativly a Magneto-capture could replace the Chemical capture but that is a low TRL tech as of right now.

The use of Lunar Gravity assists is almost a 3rd form of propulsion and looks very clever.

Over all the SEP system they are using looks very conservative, it's using older thrusters at modest ISP and low total power ~200 kw which is just 4x more then ARM and well below what had been considered necessary in the past for a human mission.  Though it dose use a very long transit time which may not prove feasible, more advanced SEP will likely need to be employed to transit faster but most mission plans like to use what is very near term of off the shelf and optimize for low IMLEO.
« Last Edit: 06/12/2015 05:00 am by Impaler »

Offline redliox

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Interesting, the Hybrid approach uses chemical propulsion only in the vicinity of Mars for capture and escape.  I suspect that simply increasing the SEP systems mass and propellent would do these same maneuvers and replace the chemical propulsion entirely while being lower in total mass.  But it would likely take longer to complete the maneuvers as they look to be making very efficient use of the Chemical propulsion where it is used.

So I noticed too.  They should use the SEP more...but obviously time poses a limit.  I'd favor the hybrid approach but I question how much chemical fuel should be relied upon; the math makes it easy to understand why Zubrin tried to persuade an ISRU-centric way to eliminate the chicken-n-egg issues.  One suggestion they seem to make is using a very distant and unstable 10-day orbit.  Interesting way to capture, but it's pretty useless for visiting the moons or getting to the surface...both of which require more stable orbits anyway.

The use of Lunar Gravity assists is almost a 3rd form of propulsion and looks very clever.

Agreed, although I was told in a pure SEP setup it couldn't be utilized because you have to couple LGA with a high thrust burn to take advantage of "the Oberth effect."

Over all the SEP system they are using looks very conservative, it's using older thrusters at modest ISP and low total power ~200 kw which is just 4x more then ARM and well below what had been considered necessary in the past for a human mission.  Though it dose use a very long transit time which may not prove feasible, more advanced SEP will likely need to be employed to transit faster but most mission plans like to use what is very near term of off the shelf and optimize for low IMLEO.

I'm getting increasingly convinced 300 kw and 3000+ ISP may become realities within a decade.  I doubt something as magical as 10,000 ISP will appear soon enough, but everything followed by three zeroes (not four just yet) seems to be on the agenda.
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Offline Robotbeat

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We have already built thrusters with 10000s Isp. But that is suboptimal because with electric propulsion, you always are trading Isp vs time since you're power-limited (for a certain mass). And even if power tech improves, you're still usually better off using that extra performance to get there faster instead of use a higher Isp (or some optimum mix of those goals). So 10000s Isp isn't a dream, but it probably is suboptimal for shortish Mars missions.
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Offline Oli

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Comparing the crew transfer times of Chemical vs Hybrid:

2033: 408 vs. 599
2037: 637 vs. 735
2041: 634 vs. 750

Definitely more, but not dramatically so. I was wondering by the way, for a Martian moons mission astronauts will experience zero-g for almost 3 years. Isn't that a dealbreaker?

Interesting way to capture, but it's pretty useless for visiting the moons or getting to the surface...

Both concepts use a crew taxi for getting to lower orbits.
« Last Edit: 06/12/2015 03:55 pm by Oli »

Offline redliox

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Comparing the crew transfer times of Chemical vs Hybrid:

2033: 408 vs. 599
2037: 637 vs. 735
2041: 634 vs. 750

Definitely more, but not dramatically so. I was wondering by the way, for a Martian moons mission astronauts will experience zero-g for almost 3 years. Isn't that a dealbreaker?

It's a factor and a challenge at least.  I think radiation is the bigger concern, but the weightless issue would be immediately second only to that.

Interesting way to capture, but it's pretty useless for visiting the moons or getting to the surface...

Both concepts use a crew taxi for getting to lower orbits.

I know they could be smaller than the main orbiter or Mars habitats, but that feels like a waste compared to developing a Mars lander itself.
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Offline TrevorMonty


There are 2 recent papers on SEP/Chemical respectively Hybrid which I think are very interesting. Maybe we can discuss them here.


Mars Conjunction Crewed Missions with a Reusable Hybrid Architecture by NASA Langley, JPL et al.

Combining Solar Electric Propulsion and Chemical Propulsion for Crewed Missions to Mars by NASA et al.


Both are attached.
Thanks Oil.

I like fact they plan to use cislunar DSH/space station at DRO for staging. Leaving the Orion behind also makes sense, why transport a heavy re enter vehicle alway to Mars and back. For same mass they can get a large habitat.

The papers only had SLS as LV no mention of commercial LVs.


Offline Oli

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The papers only had SLS as LV no mention of commercial LVs.

The Hybrid concept potentially offers a role for commercial/international.

SLS with its good BEO performance is useful though. It allows you to use less and/or less powerful SEPs.

Offline Impaler

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Leaving the Orion behind also makes sense, why transport a heavy re enter vehicle alway to Mars and back. For same mass they can get a large habitat.

This is really quite radical considering how much Orion has been hyped as 'TEH vehicle to take us to Mars' but as soon as your looking at a reusable transit vehicle capable of parking into any kind of cis-lunar orbit the need to take the Orion beyond cis-lunar completely disappears and you only need to use it as a taxi-craft to and from the transit vehicle, a purpose for which IS reasonably well adapted for, BUT it makes using an entire SLS to launch for taxi purposes alone horribly inefficient, we could just use a smaller rocket to send Orion trans-lunar, or better yet a long-duration Dragon on FH.

Offline redliox

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This is really quite radical considering how much Orion has been hyped as 'TEH vehicle to take us to Mars' but as soon as your looking at a reusable transit vehicle capable of parking into any kind of cis-lunar orbit the need to take the Orion beyond cis-lunar completely disappears and you only need to use it as a taxi-craft to and from the transit vehicle, a purpose for which IS reasonably well adapted for, BUT it makes using an entire SLS to launch for taxi purposes alone horribly inefficient, we could just use a smaller rocket to send Orion trans-lunar, or better yet a long-duration Dragon on FH.

I'm at least glad they've acknowledged Orion is more of a dead weight for anything beyond the Moon.  However yeah, if you do rendezvous in LEO utilizing something like Dragon instead that would be more cost effective.  In Orion's defense though, you could justify using an SLS flight on a taxi-like service if the Orion is hauling a small cargo pod with it; i.e. the Orion and SLS make it into a logistics flight as well as crew transfer.  All the same, Orion should only be used if you're using the Moon or its Lagrange points in flight.
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Offline Impaler

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Yea hauling some cargo or fuel with you would certainly help to fill out the SLS block II capacity.  It gets tricky though because each mission requires both a crew delivery and a crew retrieval, and it's unlikely that you could combine-dovetail both of these into a single crew-rotation mission like we do on ISS because of the synod cycle.  Do all the consumables for a mission combine to that much mass?  And if we just had better SEP then wouldn't we have the time and propellent available to bring the transit vehicle to LEO and re-outfit (both propellent and crew consumables) in LEO at vastly lower cost using our Commercial launchers and ISS delivery systems.

Offline redliox

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Yea hauling some cargo or fuel with you would certainly help to fill out the SLS block II capacity.  It gets tricky though because each mission requires both a crew delivery and a crew retrieval, and it's unlikely that you could combine-dovetail both of these into a single crew-rotation mission like we do on ISS because of the synod cycle.  Do all the consumables for a mission combine to that much mass?  And if we just had better SEP then wouldn't we have the time and propellent available to bring the transit vehicle to LEO and re-outfit (both propellent and crew consumables) in LEO at vastly lower cost using our Commercial launchers and ISS delivery systems.

I actually did some calculations related to SEP.  If you're hauling something like a DSH/Skylab 2 for either a Lunar or Martian mission it would weigh about 50 metric tons (usually a lil less).  Assuming the SEP module is launched separate and you use a full load from the EUS, it could push the setup to around 3 km/s - into a big elliptical orbit.  The SEP would use about 4 mt of xenon (assuming about 3000 ISP and a total mass around 100 mt) to move it a further 1 km/s which is enough to get it at least to EML-1.  When Orion comes to visit and assuming it's using a Block 1B SLS, it could easily deliver a fuel pod containing 10-20 mt of xenon, most likely with a few hundred pounds of life support stuff and maybe some external hardware.
« Last Edit: 06/13/2015 08:11 pm by redliox »
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Offline Impaler

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I think the main problem is the very slow Earth spiral time of the SEP or SEP/CP hybrid vehicle.  Short of developing MW scale SEP I think the solution is to simply employ a second identical transit vehicle fitted with large tanks and a pressurized cargo container (think ATV) and have this perform the job of re-outfitting the DSH and transit vehicle. 

This second vehicle just never leaves cis-lunar space and even with the long 1 year spiral time it would have no trouble completing a round trip once per synod.  As the Mars bound vehicle can only do one round trip to Mars every OTHER synod we would need only one cis-lunar tanker to service two vehicles cycling between Earth and Mars.

This replaces 2 SLS launches per mission with 3 Falcon Heavy launches, 1 to LEO with propellent/consumables load and 2 with BEO Dragon capsules for crew delivery and retrieval.  While were at it lets just launch the SEP vehicles on FH, again 2 FH substituting for 1 SLS, it would require 5 launches to set up the 2 DSH and 3 SEP stages, then you in the grove of using 3 launch per mission plus the destination systems which can be as much or as little as we want.

Offline sdsds

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This is really quite radical

I'm at least glad they've acknowledged Orion is more of a dead weight for anything beyond the Moon

They are trading an efficiency gain versus a perceived safety gain. In the case of a crew member that needs prompt medical aid beyond what the Crew Medical Officers can provide an extra week could mean the difference between a survivable condition and a fatal condition.

I'm not personally supporting one approach over the other. I hope instead a rational trade can be made, rather than a political one.
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Offline TrevorMonty

There is one possible advantage to mars crew returning to a LDRO spacestation.
If the station had a centrifuge then they could spend a few weeks here getting use to gravity again before returning to earth.

By 2030s I would hope the LDRO space station would be serviced by commercial cargo and crew vehicles. This should be the case if there is commercial lunar base. If there is lower cost commercial transport to cis lunar space then the TMI could be done with LH stage eg ACES that is refueled at LDRO.

Offline Oli

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It gets tricky though because each mission requires both a crew delivery and a crew retrieval

I don't see why. Orion should be capable of staying in cis-lunar space for ~3 years, or not?

Offline QuantumG

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I don't see why. Orion should be capable of staying in cis-lunar space for ~3 years, or not?

"~21 days maximum active crew time + ~6 months quiescent operations during lunar habitation" according to the Ames ECLSS System Engineering Workshop.
Human spaceflight is basically just LARPing now.

Offline Oli

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I don't see why. Orion should be capable of staying in cis-lunar space for ~3 years, or not?

"~21 days maximum active crew time + ~6 months quiescent operations during lunar habitation" according to the Ames ECLSS System Engineering Workshop.

Ok...so for a Mars mission it would have needed the transfer habitat for...what exactly? Assuming there is a station in cis-lunar space, it could dock there for 3 years...or not?

Offline QuantumG

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Ok...so for a Mars mission it would have needed the transfer habitat for...what exactly? Assuming there is a station in cis-lunar space, it could dock there for 3 years...or not?

I strongly doubt it. Looks like they're designing it for 6 months in space. Just another pothole in the road to Mars.
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Offline A_M_Swallow

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I don't see why. Orion should be capable of staying in cis-lunar space for ~3 years, or not?

"~21 days maximum active crew time + ~6 months quiescent operations during lunar habitation" according to the Ames ECLSS System Engineering Workshop.

Ok...so for a Mars mission it would have needed the transfer habitat for...what exactly? Assuming there is a station in cis-lunar space, it could dock there for 3 years...or not?


The missing factor is that after many high level requirements changes Orion and SLS have probably been designed for Apollo style Moon missions rather than Mars missions.

Offline Impaler

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If the arrival of one mission back from Mars to the LDRO is happening within 6 months of the next crew departure then it might be possible to use one vehicle to deliver the new crew and take back the old crew.

But both crew would need to occupy the transit vehicle at the same time, which means double the ECLSS capacity which is wasted mass for the entire mission.  Thus I think you would need that 'gateway' station concept to facilitate this and probably help in the logistical restocking/refueling of the transit vehicle.

It is not completely out of the question by the crew would be looking at 2 full synods away from Earth (the SEP they propose is to slow to do a round trip in 1 synod), which is likely to be prohibitive from a human health perspective given our current health effect mitigation capabilities.

Offline TrevorMonty

There should still be regular crew missions to LDRO space station, even while a Mars mission is in progress. So rotating the Orion shouldn't be a problem. Even if there are no manned trips an unmanned replacement Orion could be used to deliver cargo using commercial LV.

Offline Zed_Noir

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There should still be regular crew missions to LDRO space station, even while a Mars mission is in progress. So rotating the Orion shouldn't be a problem. Even if there are no manned trips an unmanned replacement Orion could be used to deliver cargo using commercial LV.

Orion is overly priced for cargo delivery, use a commercial cargo or crew variant instead.

Offline yg1968

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Teaser from Chris's latest article:

Quote
However, getting to Mars is literally a long way away, both from a technical and funding standpoint. (A series of articles outlining NASA’s latest – and surprisingly expansive – Mars mission planning will be published over the coming days.)

http://www.nasaspaceflight.com/2015/09/orion-passes-kdp-c-cautious-2023-crew-debut/
« Last Edit: 09/18/2015 09:04 pm by yg1968 »

Offline yg1968

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There is some interesting information on the role of commercial companies for the Mars Evolvable Campaign at the July 2015 NASA HEOC NAC Meeting:

Quote
Mr. Crusan discussed EMC plans for FY 2016. He reviewed a chart on recent accomplishments. He described the challenges involved in transporting crew and cargo to and from deep space. The SLS will be used to transport crew and cargo to cislunar space. The Orion will support crew during that trip. Commercial launch vehicles (LVs) will deliver logistics and small cargo to cislunar space. Habitation will be needed to protect and support crew in deep space for up to 60 days in cislunar and up to 1100 days in the Mars vicinity. Mr. Crusan explained that any initial, short-duration habitation module in the Proving Ground of cislunar space would serve as the initial building block required for Mars-class habitation.

http://www.nasa.gov/sites/default/files/files/HEO_Minutes_2015_7_27_29_FINALrev1_Bowersox_Comments_100415.pdf

http://www.nasa.gov/sites/default/files/files/Crusan_EMC_and_TechDev_NAC_TAGGED.pdf
« Last Edit: 11/07/2015 02:17 am by yg1968 »

Offline sdsds

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Lots of interesting stuff in the Crusan PDF. Two examples:

Page 15:
Quote
Commercial Launch
Use commercial launch vehicles to deliver logistics and
small cargo to cis-lunar space
Small cargo vehicle to deliver up to 11 t to TLI
Shroud = 5 m diameter

page 17:
Quote
Common LOX/CH4 Pump-Fed Engine:
Thrust: 25 klbf
Isp: 355-360 s
Up to 15 year lifetime
150-500 s burn time
5:1 throttling
Near-ZBO storage with
90 K cryocooler
LOX/CH4 Pressure-Fed RCS:
Thrust: 100-1000 lbf; Isp: 320 s
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Online mikes

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p34 of the Crusan PDF under the heading
"Common avionics components and architectures for exploration systems"
they have a picture of a Raspberry Pi.

That should help with keeping the costs down :)

Offline yg1968

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One thing that Crusan mentionned at the November 4 HEOC NAC meeting is that they have yet to decide if Orion will go to Mars or not. He said that there was arguments in favour of both options (Orion going to Mars or Orion not got going further than the cislunar staging point).
« Last Edit: 11/07/2015 03:36 pm by yg1968 »

Offline TrevorMonty

One thing that Crusan mentionned at the November 4 HEOC NAC meeting is that they have yet to decide if Orion will go to Mars or not. He said that there was arguments in favour of both options (Orion going to Mars or Orion not got going further than the cislunar staging point).
I didn't think the Orion has life for 2-3yr mission see quote from Wikipedia.

"It is designed to support long-duration deep space missions, with up to 21 days active crew time plus 6 months quiescent.[33] During the quiescent period crew life support would be provided by another module such as aDeep Space Habitat."

As returning crew I would feel lot safer reentering in a Orion that has only be in space a few weeks.

Offline ncb1397

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One thing that Crusan mentionned at the November 4 HEOC NAC meeting is that they have yet to decide if Orion will go to Mars or not. He said that there was arguments in favour of both options (Orion going to Mars or Orion not got going further than the cislunar staging point).
I didn't think the Orion has life for 2-3yr mission see quote from Wikipedia.

"It is designed to support long-duration deep space missions, with up to 21 days active crew time plus 6 months quiescent.[33] During the quiescent period crew life support would be provided by another module such as aDeep Space Habitat."

As returning crew I would feel lot safer reentering in a Orion that has only be in space a few weeks.

I think this is confusing requirements with capability. The capability could be greater than the requirement. An example of a system that greatly exceeded the endurance requirement is the MER rovers. What is limiting Orion to 6 months in space when it isn't supporting a crew? Radiation? Micrometeroid risk? Consumables? Seems if these are a problem, they can be fixed without adding much mass. Computers can be hardened, an Orion operating in the near Mars environment doesn't need to re-enter so shield damage might not be a problem, add more consumables to offset the leak rate, etc.

Some Mars architectures require a taxi in near Mars space to ferry astronauts between the MAV and the MTV or between the MTV and a martian moon hab. Seems that Orion, having been designed to operate in cislunar space, fits these rolls well.

Offline RonM

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One thing that Crusan mentionned at the November 4 HEOC NAC meeting is that they have yet to decide if Orion will go to Mars or not. He said that there was arguments in favour of both options (Orion going to Mars or Orion not got going further than the cislunar staging point).
I didn't think the Orion has life for 2-3yr mission see quote from Wikipedia.

"It is designed to support long-duration deep space missions, with up to 21 days active crew time plus 6 months quiescent.[33] During the quiescent period crew life support would be provided by another module such as aDeep Space Habitat."

As returning crew I would feel lot safer reentering in a Orion that has only be in space a few weeks.

I think this is confusing requirements with capability. The capability could be greater than the requirement. An example of a system that greatly exceeded the endurance requirement is the MER rovers. What is limiting Orion to 6 months in space when it isn't supporting a crew? Radiation? Micrometeroid risk? Consumables? Seems if these are a problem, they can be fixed without adding much mass. Computers can be hardened, an Orion operating in the near Mars environment doesn't need to re-enter so shield damage might not be a problem, add more consumables to offset the leak rate, etc.

Some Mars architectures require a taxi in near Mars space to ferry astronauts between the MAV and the MTV or between the MTV and a martian moon hab. Seems that Orion, having been designed to operate in cislunar space, fits these rolls well.

Since the current Orion design is for cis-lunar operations, taking it to Mars would require an upgrade, probably expensive. Simpler to use the current design and not take it to Mars, especially with a reusable interplanetary vehicle that can return to cis-lunar space.

Now if there is a requirement to ferry crew in Mars orbit, then it would make sense to use an upgraded Orion instead of developing another vehicle.

Offline Robotbeat

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Yeah, Orion would need several modifications to do Mars return. If you want a temporary "lifeboat" capability, you're better off with a much lighter weight SEV or maybe a Cygnus module or something.
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Offline Khadgars

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One thing that Crusan mentionned at the November 4 HEOC NAC meeting is that they have yet to decide if Orion will go to Mars or not. He said that there was arguments in favour of both options (Orion going to Mars or Orion not got going further than the cislunar staging point).
I didn't think the Orion has life for 2-3yr mission see quote from Wikipedia.

"It is designed to support long-duration deep space missions, with up to 21 days active crew time plus 6 months quiescent.[33] During the quiescent period crew life support would be provided by another module such as aDeep Space Habitat."

As returning crew I would feel lot safer reentering in a Orion that has only be in space a few weeks.

I think this is confusing requirements with capability. The capability could be greater than the requirement. An example of a system that greatly exceeded the endurance requirement is the MER rovers. What is limiting Orion to 6 months in space when it isn't supporting a crew? Radiation? Micrometeroid risk? Consumables? Seems if these are a problem, they can be fixed without adding much mass. Computers can be hardened, an Orion operating in the near Mars environment doesn't need to re-enter so shield damage might not be a problem, add more consumables to offset the leak rate, etc.

Some Mars architectures require a taxi in near Mars space to ferry astronauts between the MAV and the MTV or between the MTV and a martian moon hab. Seems that Orion, having been designed to operate in cislunar space, fits these rolls well.

Since the current Orion design is for cis-lunar operations, taking it to Mars would require an upgrade, probably expensive. Simpler to use the current design and not take it to Mars, especially with a reusable interplanetary vehicle that can return to cis-lunar space.

Now if there is a requirement to ferry crew in Mars orbit, then it would make sense to use an upgraded Orion instead of developing another vehicle.

I think a good argument can be made either way.  I don't see why we can't have several variants of Orion, and if we do need the ability to ferry crew in Mars orbit it makes a lot of sense to have Orion be that vehicle.
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Offline Bob Shaw

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Several things limit the lifetimes of quiescent vehicles.

Included among these are (off the top of my head, your mileage may vary):

Solar array degradation
Micrometeoroid and orbital debris
Optics degradation
Battery lifetimes

And, the showstopper: RCS and main propulsion unit degradation - pipework and seals in particular.


Offline Coastal Ron

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I don't see why we can't have several variants of Orion

Each variant would cost significant amounts of money though, so your base system better be what you want to stick with for decades to come.

Quote
...and if we do need the ability to ferry crew in Mars orbit it makes a lot of sense to have Orion be that vehicle.

It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

Every dollar we spend on mutating the Orion into something capable of going beyond the region of the Moon is that much less we can spend on creating a reusable space-only transportation system that will allow us to expand humanity out into space in increments greater than the 4ea/capsule the Orion currently limits us to.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline ThereIWas3

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Invoking Yuri Kondratyuk.

A series of specialized vehicles, though more complicated to develop, might result in big enough savings in total Earth-departure mass to make it worthwhile.  This approach was used on Apollo.

The heatshield you use to land on Mars does not have to be hoisted into Mars orbit again, just so you can use to land back on Earth.  The Earth re-entry shield has to be much heavier anyway.

Does the Earth Return Vehicle need to carry the Earth Rentry Vehicle all the way to Mars and back?   Not if you can rendesvous back is cis-Lunar space with your Reentry vehicle.  This has the added problem of requiring a large loss in Velocity, which is expensive to accomplish: either greatly increase mission duration or some propulsive braking.   Direct entry to Earth from a Mars return orbit not including Venus flyby is going to be 'hot'.  It also requires very precise navigation and timing of Mars departure.  Having an intermediate stop in Earth orbit makes that a lot more reliable, and while in this orbit you might as well transfer to the smaller Earth Reentry Vehicle that you did not have to haul to Mars and back.

So you get increased flexibility and safety by having an Earth Orbit Rendesvous on the way back from Mars.  The question is, how do you slow down, how much of the Return vehicle do you need to slow down, and what does this due to total mission mass?

And maybe the Earth Reenty Vehicle does not have to loiter very long, if it is not launched until shortly before it is needed.  Orion's loiter capability is certainly long enough, but Orion is way over-engineered for a simple Earth Reentry mission.  A Dragon2 could easily do it.
2. You can save even more if the Earth-reentry shielld does not got hauled even to Mars orbit, provided

Offline Robotbeat

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Refueling makes it feasible for one vehicle to serve multiple roles.
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Offline ThereIWas3

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Refueling makes it feasible for one vehicle to serve multiple roles.

But the goal here is to reduce the amount of mass that has to be accelerated and decelerated, dropped into gravity wells and boosted out again, thereby reducing the amount of fuel that is needed in the first place.

Offline Robotbeat

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Refueling makes it feasible for one vehicle to serve multiple roles.

But the goal here is to reduce the amount of mass that has to be accelerated and decelerated, dropped into gravity wells and boosted out again, thereby reducing the amount of fuel that is needed in the first place.
Why are we focused on reducing amount of fuel? Is fuel really a good stand-in for cost, especially when much of it at the end will be picked up at the destination?
« Last Edit: 11/11/2015 03:35 am by Robotbeat »
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Offline sdsds

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Why are we focused on reducing amount of fuel? Is fuel really a good stand-in for cost, especially when much of it at the end will be picked up at the destination?

Well phrased! Picking up propellant anywhere along the way breaks the tyranny of the rocket equation.

There's another tyranny, though: funding. I hope NASA is learning the secrets to break that tyranny as well. The current SLS approach is to trickle dollars at all the "right" suppliers. (As an example, I think dollars are still trickling towards Orbital/ATK for "risk reduction" research into advanced solid propellants. But the trickle is so small it gets little or no notice.)

Regarding Orion and Mars, I predict we will see NASA trickle dollars towards Lockheed Martin, asking them to do "risk reduction" on Orion-derived vehicles. Perhaps a capsule with a better heat shield, or a variant with no heat shield, etc.
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Offline MP99

It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

Cheers, Martin

Offline ncb1397

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It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

Cheers, Martin
Or you return the crew through aerobraking and the MTV eventually maneuvers to capture into Earth orbit through SEP. You pretty much have to use chemical for capture to get the crew down in an expedited fashion otherwise

Offline Khadgars

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Why are we focused on reducing amount of fuel? Is fuel really a good stand-in for cost, especially when much of it at the end will be picked up at the destination?

Well phrased! Picking up propellant anywhere along the way breaks the tyranny of the rocket equation.

There's another tyranny, though: funding. I hope NASA is learning the secrets to break that tyranny as well. The current SLS approach is to trickle dollars at all the "right" suppliers. (As an example, I think dollars are still trickling towards Orbital/ATK for "risk reduction" research into advanced solid propellants. But the trickle is so small it gets little or no notice.)

Regarding Orion and Mars, I predict we will see NASA trickle dollars towards Lockheed Martin, asking them to do "risk reduction" on Orion-derived vehicles. Perhaps a capsule with a better heat shield, or a variant with no heat shield, etc.

Agreed, very likely Lockheed Martin will get some funding to research an Orion based taxi.  I think it's definitely worth looking into and seeing what the options are.
Evil triumphs when good men do nothing - Thomas Jefferson

Offline Coastal Ron

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It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

You are right, that hauling a heatshield makes sense if you would spend more to decelerate without one.

My line of thought is that depending on the Orion to do a direct return to Earth limits the number of people that can be beyond Earth to the number of Orion that can be sent.  And though many could be sent, the Orion is an expensive system that is at best only partially reusable.  And it's not expandable, since it's size is pretty much the limit of what capsules can be for return to Earth.

So if we will need a different method of return from BEO destinations, then why wait to create it?  And there are other methods of orbital capture besides propulsive, but even propulsive capture is doable if propellant becomes a commodity in space.

I just don't want it assumed that we have to be limited by using the Orion - there are options that we have to perfect anyways if we want to expand humanity out into space.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Robotbeat

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Why are we focused on reducing amount of fuel? Is fuel really a good stand-in for cost, especially when much of it at the end will be picked up at the destination?

Well phrased! Picking up propellant anywhere along the way breaks the tyranny of the rocket equation.

There's another tyranny, though: funding. I hope NASA is learning the secrets to break that tyranny as well. The current SLS approach is to trickle dollars at all the "right" suppliers. (As an example, I think dollars are still trickling towards Orbital/ATK for "risk reduction" research into advanced solid propellants. But the trickle is so small it gets little or no notice.)

Regarding Orion and Mars, I predict we will see NASA trickle dollars towards Lockheed Martin, asking them to do "risk reduction" on Orion-derived vehicles. Perhaps a capsule with a better heat shield, or a variant with no heat shield, etc.

Agreed, very likely Lockheed Martin will get some funding to research an Orion based taxi.  I think it's definitely worth looking into and seeing what the options are.
Unfortunately, modifying Orion for refueling (necessary for this sort of thing to be worthwhile, IMHO) sounds difficult from what Orion people have told me. Although honestly, I think the idea of refueling to them is pretty new... they haven't really considered it! Thus it may not be that bad.
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Offline A_M_Swallow

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Unfortunately, modifying Orion for refueling (necessary for this sort of thing to be worthwhile, IMHO) sounds difficult from what Orion people have told me. Although honestly, I think the idea of refueling to them is pretty new... they haven't really considered it! Thus it may not be that bad.

The Orion uses an implementation of the NASA Docking System (NDS). The NDS is based on the international Low Impact Docking System (iLIDS). As standard this comes with interfaces to transfer power, data, commands, air and communication. Enhancements to support the transfer of water, fuel, oxidizer and pressurant are being worked on.

The main things the Orion team will have to add for refuelling are the pipes, valves, any holes in the fuselage and the control system.
https://en.wikipedia.org/wiki/NASA_Docking_System
« Last Edit: 11/13/2015 06:48 am by A_M_Swallow »

Offline sdsds

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I don't believe the Orion Crew Module Adapter (CMA) provides any way to transfer propellant between the Crew Module and the Service Module. But I suppose the Crew Module's RCS propellant supply could be refilled by transfer through the docking adapter....

(If anyone wants to assert the CMA does facilitate propellant transfer between the modules, I'd love to be corrected with a source citation!)
« Last Edit: 11/13/2015 07:31 am by sdsds »
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Offline A_M_Swallow

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I don't believe the Orion Crew Module Adapter (CMA) provides any way to transfer propellant between the Crew Module and the Service Module. But I suppose the Crew Module's RCS propellant supply could be refilled by transfer through the docking adapter....

(If anyone wants to assert the CMA does facilitate propellant transfer between the modules, I'd love to be corrected with a source citation!)

Possibly not but will CMA version 2.0 support propellant transfer?

Offline Robotbeat

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As I said, Orion most certainly does NOT have any capability to transfer propellant. It would need to be substantially modified to do so. And I am disappointed not much thought was apparently given to that.
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Offline MP99



It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

Cheers, Martin
Or you return the crew through aerobraking and the MTV eventually maneuvers to capture into Earth orbit through SEP. You pretty much have to use chemical for capture to get the crew down in an expedited fashion otherwise

So, you're saying it makes sense to carry the heatshield even if the MTV is recovered by SEP?

Cheers, Martin

Offline ncb1397

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It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

Cheers, Martin
Or you return the crew through aerobraking and the MTV eventually maneuvers to capture into Earth orbit through SEP. You pretty much have to use chemical for capture to get the crew down in an expedited fashion otherwise

So, you're saying it makes sense to carry the heatshield even if the MTV is recovered by SEP?

Cheers, Martin

I'm saying that the the MTV does a transfer for a near miss with Earth. A few days before the Earth pass, crew loads up in Orion and does a divert with the service module to interception with Earth. The heat shield is useful here because it is used in place of propellant. Just because the MTV passes Earth here, it is not necessarily expended. It is still out there in functioning condition. I believe with high efficiency SEP, the MTV can capture back into Earth orbit within the next couple of years or so. The most efficient orbital mechanics for this though are above my pay grade. If there was no heat shield, Orion or the MTV would have to expend chemical propellant to do an orbit insertion maneuver that is very expensive. This chemical propellant was hauled all the way to Mars and back through all those burns. IMO making a variant without the heatshield isn't worth it because in certain emergency scenarios, say because of a launch failure with the Orion that is supposed to pick them up in cislunar space, you may have to do direct return even if that means expending the MTV. Having the heatshield allows for a plan B.

Offline Coastal Ron

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It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

Or you return the crew through aerobraking and the MTV eventually maneuvers to capture into Earth orbit through SEP. You pretty much have to use chemical for capture to get the crew down in an expedited fashion otherwise

So, you're saying it makes sense to carry the heatshield even if the MTV is recovered by SEP?


I'm saying that the the MTV does a transfer for a near miss with Earth. A few days before the Earth pass, crew loads up in Orion and does a divert with the service module to interception with Earth. The heat shield is useful here because it is used in place of propellant...

Originally when I brought this up it was not necessarily to debate the overall energy requirements of slowing down for Earth orbit or doing a direct entry with a single vehicle that had a heatshield.

The more important issue is that if we know that we will be wanting vehicles that can return more than 4-6 people at a time from Mars (the size of the current Orion), then we should start working on that now.  We know SpaceX is, since their MCT is a reusable vehicle that will supposedly carry far more than 6 people at a time.  Not that it means they have solved the problem, only that they have decided they don't want to be limited by what the Orion transportation capabilities are.

I would imagine the eventual solution will involve either fuel or time, or both.  For instance, it could be that some form of SEP will be used by a vehicle returning from Mars to be captured by the Earth-Moon system, but that it will take time (i.e. weeks, months) in order to ultimately slow down and enter LEO when the passengers will be able to transfer to something like the upcoming Commercial Crew vehicles.  Or maybe the system will use chemical propulsion and do it much quicker, but it would obviously need to have a higher logistics requirement to maintain that type of system if it's used a lot.

So while Orion could be used, it's too limiting by itself to expand humanity out beyond Earth.  We'll need something different, something better.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline ncb1397

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It makes no sense to haul a heatshield around in deep space.  It is a waste of propellant to haul it halfway across the solar system and back just so that you'll have it when you return to Earth.

You are assuming that the MTV performs a propulsive capture at Earth, so it can be used again. Once you've done that, you can rendezvous with your reentry capsule.

It does make sense to haul a heatshield around in deep space if that mass replaces the prop to do that dV for the capture, IE you allow the MTV to be expended.

Or you return the crew through aerobraking and the MTV eventually maneuvers to capture into Earth orbit through SEP. You pretty much have to use chemical for capture to get the crew down in an expedited fashion otherwise

So, you're saying it makes sense to carry the heatshield even if the MTV is recovered by SEP?


I'm saying that the the MTV does a transfer for a near miss with Earth. A few days before the Earth pass, crew loads up in Orion and does a divert with the service module to interception with Earth. The heat shield is useful here because it is used in place of propellant...

Originally when I brought this up it was not necessarily to debate the overall energy requirements of slowing down for Earth orbit or doing a direct entry with a single vehicle that had a heatshield.

The more important issue is that if we know that we will be wanting vehicles that can return more than 4-6 people at a time from Mars (the size of the current Orion), then we should start working on that now.  We know SpaceX is, since their MCT is a reusable vehicle that will supposedly carry far more than 6 people at a time.  Not that it means they have solved the problem, only that they have decided they don't want to be limited by what the Orion transportation capabilities are.

I would imagine the eventual solution will involve either fuel or time, or both.  For instance, it could be that some form of SEP will be used by a vehicle returning from Mars to be captured by the Earth-Moon system, but that it will take time (i.e. weeks, months) in order to ultimately slow down and enter LEO when the passengers will be able to transfer to something like the upcoming Commercial Crew vehicles.  Or maybe the system will use chemical propulsion and do it much quicker, but it would obviously need to have a higher logistics requirement to maintain that type of system if it's used a lot.

So while Orion could be used, it's too limiting by itself to expand humanity out beyond Earth.  We'll need something different, something better.

We haven't even landed one person yet. That is the first step before we start thinking about the engineering to move a million. IMO it isn't NASA's job to colonize Mars. It is NASA's job to push the frontiers of the art of the possible. They can show that you can land on the moon and return him back to earth. They can show that you can grow food in Mars soil and live there for a long time. They can send probes to progressively farther bodies in the solar system and interstellar space and determine what is out there and what it is made of. They can show that you can alter the trajectory of an asteroid if that is something you need to do. Let SpaceX do what they are doing and NASA do what they are doing. They don't have to be doing the same thing. Maybe their MCT works better, maybe NASA's system does. I wouldn't put all my eggs in one basket though.

Offline philw1776

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Is there or will there be a site where presentation slides or pdf documents advocating the various sites are archived for public access?
FULL SEND!!!!

Offline Oli

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New paper: In-Space Transportation for NASA’s Evolvable Mars Campaign

« Last Edit: 11/22/2015 01:19 am by Oli »

Offline Coastal Ron

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...
So while Orion could be used, it's too limiting by itself to expand humanity out beyond Earth.  We'll need something different, something better.

We haven't even landed one person yet. That is the first step before we start thinking about the engineering to move a million. IMO it isn't NASA's job to colonize Mars.

And I'm OK with that.  But other than the NASA Charter NASA doesn't have an approved goal for going to Mars, one that is specifically called out in legislation.  And unless that happens, NASA's goals for Mars are whatever the current Administration wants them to be.  In other words, fuzzy and unconnected.

Quote
It is NASA's job to push the frontiers of the art of the possible. They can show that you can land on the moon and return him back to earth. They can show that you can grow food in Mars soil and live there for a long time.

We went to the Moon to show up the USSR as part of the Cold War.  Science, "because it's there", and everything else was just along for the ride.  The ISS is really the only manned effort that has had a specific human space science mandate, but even that was heavily influenced by the end of the Cold War.  Face it, we don't have any pure motives for NASA to send humans into space right now.

Quote
Let SpaceX do what they are doing and NASA do what they are doing. They don't have to be doing the same thing. Maybe their MCT works better, maybe NASA's system does. I wouldn't put all my eggs in one basket though.

Sure, multiple approaches are good.  But my point was that if NASA is limited to sending people to space and back again in 4 person increments, that's not very forward thinking of them.  If NASA is going to be sending humans to space, then everything they do should support sending progressively more and more people to space.  Otherwise NASA will always be limited in what it can support.

For instance, in the current proposal two SLS have to be dedicated to sending 4 people to Mars and returning them to Earth.  You want 8 people on Mars?  That's 4ea SLS.  That's not scaleable.  We should be working on fixing that now, not when it's too expensive.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

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Offline philw1776

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FULL SEND!!!!

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Offline yg1968

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Offline Oli

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PDF of all the Mars Manned Landing Sites Presentations

http://www.nasa.gov/sites/default/files/atoms/files/mars-c-abstracts_in_order_of_presentation10242015_0.pdf

I've read and heard more about planetary protection recently (for example on thespaceshow) and I think that's going to be a huge issue for manned missions. In fact it looks like there's no way around teleoperation of robotic assets since the regions you want to explore are exactly the ones that need protection. The question then is of course why land at all.
« Last Edit: 03/22/2016 01:37 am by Oli »

Offline Robotbeat

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"Earth Independence."

By just using the pure science justification for human spaceflight, we're tying both arms behind our back.
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Offline BrightLight

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A massive 598 page document on Mars Design Reference Architecture (DRA) manned missions

http://ntrs.nasa.gov/search.jsp?R=20160003093&hterms=exploration+augmentation+habitat&qs=Ntx%3Dmode%2Bmatchallany%26Ntk%3DAll%26Ns%3DAcquired-Date|1%26N%3D0%26Ntt%3Dexploration%2Baugmentation%2Bhabitat


Offline Dalhousie

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PDF of all the Mars Manned Landing Sites Presentations

http://www.nasa.gov/sites/default/files/atoms/files/mars-c-abstracts_in_order_of_presentation10242015_0.pdf

I've read and heard more about planetary protection recently (for example on thespaceshow) and I think that's going to be a huge issue for manned missions. In fact it looks like there's no way around teleoperation of robotic assets since the regions you want to explore are exactly the ones that need protection. The question then is of course why land at all.

Planetary protection is very easily exaggerated.  So far there are no confirmed special regions, and most potential special reasons regions are subsurface, you can have crew on the surface drilling down with appropriate equipment.  Teleoperation is also much easier when done on site as well, from a few metres away, than from orbit.

Apologies in advance for any lack of civility - it's unintended

Offline redliox

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Something I've noticed while reading through the presentations: a 5-sol orbit around Mars may apparently be favored over the original 1-sol/synchronous orbit now.  Anywhere else seems to be restricted to visiting Phobos or Mars itself.  Offhand I presume this is a conservative choice regarding fuel and delta-v.  Anyone have any thoughts regarding this change?
« Last Edit: 06/01/2016 07:32 am by redliox »
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Offline guckyfan

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My understanding of orbital mechanics is quite limited. I think a high circular orbit is expensive delta-v wise. Elliptical orbit would be ok but does make rendezvous more restricted. Also would Phobos and Deimos interfere with elliptical orbits, small as they are?

Offline redliox

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My understanding of orbital mechanics is quite limited. I think a high circular orbit is expensive delta-v wise. Elliptical orbit would be ok but does make rendezvous more restricted. Also would Phobos and Deimos interfere with elliptical orbits, small as they are?

What I understand of orbital mechanics is that circularizing an elliptical orbit is where things get expensive delta-v wise, which is what they're apparently skipping.  They do seem intent on a 5-sol orbit to somewhat synchronize, if not fully ease, rendezvous on further note.  Also regarding the moons, both are inclined roughly a degree away from the Marian equator; if the orbit is inclined say 5 degrees (maybe even less), that would never cross their paths while retaining an equatorial orientation.

The bigger implication I realize relates to the surface expeditions.  The Langley documents say very little about what actually happens with EDL or on the surface in general (and given they're focusing on the orbital propulsion stage this is understandable), but they do mention at least 8 landers will descend to Mars, 2 of which will be crewed and presumably 2 will be Mars Ascent Vehicles positioned ahead.  All these landers are apparently going to be descending from the 5-sol orbit, one way or another, without further assistance from their carrier propulsion stage.  This means they'll have to burn, chemically or via aerobraking (the former on ascent), close to 5 km/s of delta-v, which is considerably more than some plans which assumed low Mars orbit, including in "The Martian."

If someone can calculate the elliptical 5-sol orbit, not to mention the direct descent delta-v from it to the surface, please do so and correct my 5 km/s assumption; I'm taking that number off a somewhat generic delta-v chart and assuming the 5-sol orbit is fairly close to the Mars capture point.

Largest point of this is the 2 MAVs sent will definitely have to carry either ISRU (and that acronym is absent from Langley's papers notably) or plenty of fuel; enough to nearly allow an escape from Mars.  The landers' mass is stated to be 43,600 kg wet.  Other documents seem to suggest a mostly dry, landed vehicle would end up as 20,000 kg or less (much less in many cases).  Aerobraking would seem like a reasonably way to shed mass but, again, the Langley papers don't really say anything regarding (they seem to imply mostly chemically though, and most likely at least some of the lander mass would be reserved for maneuvering fuel).  The large orbit would require plenty of propellant, and LOX production seems to appear more often on NASA's papers if not complete LOX/CH4 manufacture.  This gives incentive for the landers to make fuel as well as prospect for resources to do so.


...I'm wondering if Robert Zubrin is smiling smugly somewhere right now...  :P
« Last Edit: 06/01/2016 05:14 pm by redliox »
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Offline Robotbeat

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Sure, but you can do this in stages. Also, a little lower since Mars is rotating. And you WOULDN'T do this propulsively. You can do one pass to lower the period of your orbit to something more manageable like, say, 10 hours, then do a few more from there before you enter from a low orbit.

High orbits are to be preferred because you DRAMATICALLY reduced braking and departure delta-v. It allows you to build huge transfer vehicles or park huge amounts of supplies there fairly cheaply. And being able to use the atmosphere to get in lower orbits helps a lot, too.

...being in a high orbit also makes changing inclination a LOT easier, too.
« Last Edit: 06/01/2016 07:07 pm by Robotbeat »
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Offline MikeAtkinson

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They do mention ISRU for the ascent stage.

Lots of interesting things in the documents.

Propulsion module reused twice(3 in total)

At least 32 SLS for 3 crew landings.

300 - 400 day surface stays.

1100 day total mission duration. 700 - 800 days in deep space.

Optimized for 47 tonnes to deep retrograde lunar orbit.

Offline MikeAtkinson

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18 tonnes payload to Mars.

Transfer between deep retrograde lunar orbit and lunar distance high earth orbit before departure and after arrival in cis-lunar space.

This takes up to 200 days, leaving 15 - 200 days for resupply.

Crewed missions take 3 Orion (1 for hybrid propulsion stage refurb).

2 SLS per year. Crew every other synod.

3rd manned mission returns in 2046.

No evolution of SLS, Orion, hybrid propulsion stage, or any other system. So optimized that it is hard to see if the evolution of any one element would improve the overall system.

32 SLS gives 3600 man-days on Mars.

Long gap between crews. Approx. 1.5 martian years.


Offline Robotbeat

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18 tonnes payload to Mars.

Transfer between deep retrograde lunar orbit and lunar distance high earth orbit before departure and after arrival in cis-lunar space.

This takes up to 200 days, leaving 15 - 200 days for resupply.

Crewed missions take 3 Orion (1 for hybrid propulsion stage refurb).

2 SLS per year. Crew every other synod.

3rd manned mission returns in 2046.

No evolution of SLS, Orion, hybrid propulsion stage, or any other system. So optimized that it is hard to see if the evolution of any one element would improve the overall system.

32 SLS gives 3600 man-days on Mars.

Long gap between crews. Approx. 1.5 martian years.
....that'd be the ISRU-lite version. They need a reusable lander (Hercules is what they call it) to enable a continual presence. Adding more ISRU then allows a build-up of crew to about 16.
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Offline redliox

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They need a reusable lander (Hercules is what they call it) to enable a continual presence. Adding more ISRU then allows a build-up of crew to about 16.

That would be a good long-term idea.  The larger and immediate priority though would be building up the Mars base (including ISRU infrastructure) and a reusable interplanetary habitat, both of which would help in the long-term.  If a one-way lander can at least contribute towards the base it would be useful, especially since MAV lower stages are supposed to incorporate ISRU.  I'd see creating a reusable Mars lander as an objective for maybe the 2040s and onward, whereas just landing on Mars is a big enough issue for the moment.
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Offline TrevorMonty

The refuelling  tankers are sized for SLS but could  be made smaller to enable commercial  LVs to be used.

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Offline Oli

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No evolution of SLS, Orion, hybrid propulsion stage, or any other system.

They discuss (minor) upgrades to the HPS, more power or higher isp chemical propulsion.

The refuelling  tankers are sized for SLS but could  be made smaller to enable commercial  LVs to be used.

Or it could be launched to LEO and transported to LDRO with a HPS (EP only).

If NASA proceeds with such an architecture it will have a hard time justifying the expenses for SLS, IMO.


Offline TrevorMonty

They still need SLS for crew and larger payloads, especially its 8M fairing. Adding commercial LVs to mix should make it more affordable and keep SLS launches to 1-2 a year.

Offline CuddlyRocket

They still need SLS for crew and larger payloads, especially its 8M fairing. Adding commercial LVs to mix should make it more affordable and keep SLS launches to 1-2 a year.
Actually it will be zero if the commercial Colonial fleet materialize by about 2025. ;)

Can we NOT bring SpaceX into this?

There are probably people at NASA asking that exact same question! :)

Offline redliox

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But on a serious note, I could see Cygnus and the Bigelow modules being potential templates for the orbital elements proposed to add more diversity to the Commercial options.  The BA-330, if not Olympus, could stand in for the habitats of the Phobos station and Cruise vehicle atop Langley's hyprid propulsion stage (which itself could be contracted out).  Hypothetically, the Cygnus could be modified to serve as the crew taxi between the 5-sol and Phobos orbits (although granted, a bit of work like life support and crew amenities would be an issue), or more easily as the Phobos exploration vehicle.

Although Lockheed's orbital lab insists on dragging Orion to Mars, it is good to see at least Langley is acknowledging it's far more practical to keep it in Cislunar, if at all, in the plan for Mars.
« Last Edit: 06/05/2016 02:42 am by Carl G »
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Offline mike robel

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They still need SLS for crew and larger payloads, especially its 8M fairing. Adding commercial LVs to mix should make it more affordable and keep SLS launches to 1-2 a year.
Actually it will be zero if the commercial Colonial fleet materialize by about 2025. ;)

Can we NOT bring SpaceX into this?

There are probably people at NASA asking that exact same question! :)

Well, first SpaceX would have to bid on an appropriate contract.  :)

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