Author Topic: "Mission to Mars Using Six 'Not So Easy' Pieces" Mike Raftery , Boeing  (Read 30698 times)

Offline sdsds

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In Boeing's proposal, Orion could easily replaced by an upgraded Dragon since the spacecraft doesn't go further than the L2 Gateway.

What? You're saying Boeing is making a proposal for SLS etc. that doesn't depend on the success of Lockheed-Martin's MPCV development effort? I wonder why they would do that?
« Last Edit: 07/10/2014 04:13 AM by sdsds »
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Offline Oli

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If EML-2 assembly is too difficult for whatever reason, I guess you could assemble both vehicles in LEO and only dock Orion with the crew vehicle at EML-2. Its just that SLS gives you the performance to launch hab+kick stage directly to EML-2, so you do not have to "spiral out" those modules.

Further I do not think SLS Block II is an essential part of this architecture. I suppose SEP tug and the Mars lander could be launched separately.
« Last Edit: 07/10/2014 07:37 AM by Oli »

Offline yg1968

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In Boeing's proposal, Orion could easily replaced by an upgraded Dragon since the spacecraft doesn't go further than the L2 Gateway.

What? You're saying Boeing is making a proposal for SLS etc. that doesn't depend on the success of Lockheed-Martin's MPCV development effort? I wonder why they would do that?

NASA didn't make the same "mistake" in their proposal. In their study, Orion comes back directly from Mars without stopping at the gateway/staging point. However, the habitat returns to the staging point/gateway in order to be refurbished. See slide 11:

http://forum.nasaspaceflight.com/index.php?topic=35122.0
« Last Edit: 07/10/2014 08:23 PM by yg1968 »

Offline Robotbeat

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Yeah, the Raftery proposal keeps Orion at EML2. Good idea, actually. You can really optimize the heck out of the transit hab that way.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline yg1968

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Yeah, the Raftery proposal keeps Orion at EML2. Good idea, actually. You can really optimize the heck out of the transit hab that way.

Yes but what happens if SpaceX decides to develop an upgraded Dragon that can make it to L2. Wouldn't NASA be forced to use the commercial option (instead of Orion) in such a case? I suspect that is why NASA's study decided to bring Orion all the way to Mars orbit.

P.S. From your sig: "To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers." 
« Last Edit: 07/10/2014 08:58 PM by yg1968 »

Offline Robotbeat

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Yeah, the Raftery proposal keeps Orion at EML2. Good idea, actually. You can really optimize the heck out of the transit hab that way.

Yes but what happens if SpaceX decides to develop an upgraded Dragon that can make it to L2. Wouldn't NASA be forced to use the commercial option (instead of Orion) in such a case? I suspect that is why NASA's study decided to bring Orion all the way to Mars orbit.

P.S. From your sig: "To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers."
Indeed. And actually, SpaceX's heatshield may be better suited to Mars entry than Orion's due to the use of PICA-X instead of Avcoat.

But NASA isn't supposed to plan missions intentionally to avoid commercial space transportation services. Constellation kind of did that, but both Raftery's architecture and NASA's architecture have spots where commercial space transportation services could take over some of the duties now served by Orion and SLS. Heck, NASA's architecture may be better off with Dragon V2 anyway since it's significantly lighter than Orion.
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 Burninate

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For human cargo, an LEO rendezvous with a chemical boost stage which brings the craft to high orbit to rendezvous with the depot / departure stage is a practical way to avoid super-heavy-lift for this sole point.

Offline Robotbeat

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That's unnecessary if you're using either Dragon or Soyuz which can launch on Falcon Heavy and Proton (or Angara) respectively. CST-100 could just about make it on Delta IV Heavy with RS-68A, careful trajectory, and use of abort propellant or could also use Falcon Heavy. You're going to the gateway, which is the logical extension of ISS to beyond LEO so may inherit much of the logistics of ISS. But yeah, it may be possible to launch Orion there Gemini style without SLS.
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 Robotbeat

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For human cargo, an LEO rendezvous with a chemical boost stage which brings the craft to high orbit to rendezvous with the depot / departure stage is a practical way to avoid super-heavy-lift for this sole point.
Just to reiterate, this is a perfectly valid way of beyond-LEO transport. Some of the Gemini missions did this and they went further from Earth than anyone has ever been since 1972. Worked just fine, and this was before our modern automated rendezvous methods were developed.



By my calculations, as long as Orion can be launched manned on D4H to LEO (should be fine), then a Hydrolox upper stage in LEO with a mass of 30t and dry of 3 should be enough to put Orion at EML2 within 20 days, with just a little help from Orion herself. The longer transit also reduces insertion delta-v, leaving more oomph for the return journey. A 2-launch architecture is perfectly doable.
« Last Edit: 07/11/2014 10:27 PM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Archibald

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The pictures on that pdf, they were so beautiful, I made a 5 minutes powerpoint animation with them. I added Coldplay "a sky full of stars" as soundtrack. I should post that on YouTube  :o
That'd be cool.

I (finally !) did it and hope you'll enjoy the video.

https://www.youtube.com/watch?v=oJcC4SKd16Y&feature=youtu.be

...you have been found guilty by the elders of the forum of a (imaginary) vendetta against Saint Elon - BLAAASPHEMER !

Offline redliox

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Are there any further details about the solar electric tug?  I'm trying to make a better judgement call about it.  I see their details about the trajectory, which is pleasant knowledge to have, and the thrust times required.

So the overall plan, from Boeing, is the slow haul to Mars both crew and humans from EML-2 to Areosynchronous orbit?  I could agree to some points about it, and maybe even live with 45 days to break the crew into orbit.  I think those six pieces could be simplified.

I think there should be a blending of Mars Direct with this; if the main concerns against Direct's straightforward approach is aerocapture and ISRU, having the solar tug allows for a safe arrival and an escape route to mitigate those concerns.
« Last Edit: 04/24/2015 09:15 AM by redliox »
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Offline sdsds

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With the reusable tug it is easy to jump to the (I think erroneous) conclusion that each subsequent Orion can launch with the SEP propellant needed to refuel the tug, and thus the mission cycle can continue as long as the tug lasts, with only launches of the cargo component and the crew component.

But that doesn't work, because it doesn't provide the SEP propellant for the subsequent cargo components. (The first time around the loop this was launched with the tug.) So you need to have another launch with the cargo SEP propellant. And either that needs to include an Orion so you can have its crew do the refueling of the tug, or you need to develop autonomous refueling.

I'm sure many here would say, "The autonomous refueling of the SEP tug is a 'no-brainer' detail." I would gladly dispute that on both technical and political grounds! ;)
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Offline guckyfan

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I'm sure many here would say, "The autonomous refueling of the SEP tug is a 'no-brainer' detail." I would gladly dispute that on both technical and political grounds! ;)

In the Jupiter concept by LM the next cargo also brings the fuel along. They bring the fuel in a new tank. If that is easier than refuelling then go that way.

Offline Robotbeat

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I'm sure many here would say, "The autonomous refueling of the SEP tug is a 'no-brainer' detail." I would gladly dispute that on both technical and political grounds! ;)

In the Jupiter concept by LM the next cargo also brings the fuel along. They bring the fuel in a new tank. If that is easier than refuelling then go that way.
Jupiter refuels from the Exoliner, it does not swap tanks.
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Offline guckyfan

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Jupiter refuels from the Exoliner, it does not swap tanks.

Does Jupiter even have tanks? It takes its fuel from the tanks Exoliner brought along. What advantage would transfering fuel have?

Offline Bob Shaw

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Jupiter refuels from the Exoliner, it does not swap tanks.

Does Jupiter even have tanks? It takes its fuel from the tanks Exoliner brought along. What advantage would transfering fuel have?

Weight.

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