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#120
by
enkarha
on 07 Dec, 2014 08:29
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BEO for Orion is lunar orbit and the Earth-Moon Lagrange points.
Not true, especially the Earth-Moon Lagrange points.
Alright, I gotta ask- what is Orion optimized for if not lunar orbit? And while EML's are not exactly its initially intended destination, they are not outside the craft's comfort zone.
Or are you just contesting that use of BEO? Now I'm wondering, did the Apollo astronauts never leave earth orbit? Or even better: when they landed, were they even "closer" to being in an Earth orbit than when they were in lunar orbit?
BEO & BLEO is certainly silly terminology though. Orion is for the high dV, low time span missions. That means anything between HEO and lunar DROs. If you're going out of that zone there's not much point taking it along. But that zone is useful for many things.
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#121
by
Zed_Noir
on 07 Dec, 2014 13:41
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BEO for Orion is lunar orbit and the Earth-Moon Lagrange points.
Not true, especially the Earth-Moon Lagrange points.
Alright, I gotta ask- what is Orion optimized for if not lunar orbit? And while EML's are not exactly its initially intended destination, they are not outside the craft's comfort zone.
Or are you just contesting that use of BEO? Now I'm wondering, did the Apollo astronauts never leave earth orbit? Or even better: when they landed, were they even "closer" to being in an Earth orbit than when they were in lunar orbit?
BEO & BLEO is certainly silly terminology though. Orion is for the high dV, low time span missions. That means anything between HEO and lunar DROs. If you're going out of that zone there's not much point taking it along. But that zone is useful for many things.
IIRC, TLI is mostly done by the Altair lander. But there is no Altair lander currently.Darn, Not correct. See M129K's posting in the next post.
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#122
by
M129K
on 07 Dec, 2014 13:46
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IIRC, TLI is mostly done by the Altair lander. But there is no Altair lander currently.
TLI was to be performed by the EDS, LOI by Altair. Both tasks can be performed by the Exploration Upper Stage on Block 1B.
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#123
by
notsorandom
on 08 Dec, 2014 13:04
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The asteroid mission has never made a lot of sense to me. By the mid 20's I expect PRI and DSI to be actively mining, or they will have failed. Further, Hayabusa 2 will get a lot more science accomplished, I expect, since it's staying at a C type asteroid for 18 months..
I doubt either PRI or DSI will be mining asteroids by then. They may have sent a small sample return mission by then, but getting to the point where they're ready for mining is a nontrivial project.
The thing most people seem to miss about this is that we'll be bringing back an asteroid or boulder that masses 90-500 tonnes. Sure, Orion will visit it once and bring back some samples, but most of that mass will still be there, now easily reachable by future NASA or commercial missions that want to study ISRU and other things. It'll be in a stable orbit that will last hundreds or thousands of years without any stationkeeping. It's a small new moon, but a new moon nonetheless. I'm a pretty dyed-in-the-wool Moon Firster, but still am intrigued by this mission, since I think it could make asteroid ISRU a much nearer term possibility.
You wouldn't get that with a robotic small sample return mission like Hayabusa 2 or anything PRI or DSI will be doing soon.
You wouldn't get that by visiting a NEO "free range" for a couple of weeks out in heliocentric orbit.
You wouldn't get that by a trip to a small asteroid that drifts through earth-moon space.
If you care about asteroid ISRU, this could be a really big deal (if done right--always got to throw in that caveat).
I could be wrong but I don't think PRI or DSI have chosen to lasso asteroids into the Earth-Moon system as part of their strategy. Unless they have changed it since I last looked PRI's first two stages are to launch prospecting satellites with telescopes into various orbits around Earth, then to launch probes to visit the NEOs they find.
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#124
by
jgoldader
on 08 Dec, 2014 17:00
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I could be wrong but I don't think PRI or DSI have chosen to lasso asteroids into the Earth-Moon system as part of their strategy. Unless they have changed it since I last looked PRI's first two stages are to launch prospecting satellites with telescopes into various orbits around Earth, then to launch probes to visit the NEOs they find.
Unless NASA forbids it, there'd be nothing preventing PRI from sending an ISRU package to the bagged NEO in lunar orbit. Of course, it would have to cut through the bag.
Now, if you're talking about sending the ISRU package along with Orion, and having the astros bolt the thing onto the asteroid, we're actually getting something interesting going.
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#125
by
jongoff
on 09 Dec, 2014 06:13
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I could be wrong but I don't think PRI or DSI have chosen to lasso asteroids into the Earth-Moon system as part of their strategy. Unless they have changed it since I last looked PRI's first two stages are to launch prospecting satellites with telescopes into various orbits around Earth, then to launch probes to visit the NEOs they find.
If you look at DSI's website, some of the art clearly shows spacecraft moving asteroids. And IIRC, several PRI personnel were involved in the Keck study that came up with the bag an asteroid concept in the first place.
If I were a small, modestly capitalized startup interested in asteroid mining, I'd start out with asteroid finding telescopes and low-cost mass-produceable probes to better scout out targets first. But when I had found some interesting targets, I would do some variant on bringing materials home to experiment on. Neither of them have the funding to attempt even a cost-optimized variant of ARM right from the start, but that doesn't mean that they're opposed or think the general idea is stupid.
~Jon
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#126
by
MP99
on 09 Dec, 2014 11:14
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Or are you just contesting that use of BEO? Now I'm wondering, did the Apollo astronauts never leave earth orbit?
The Moon orbits the Earth. By definition, that's "Earth Orbit", not "Beyond Earth Orbit".
Anything that lands on the Moon, or orbits the Moon, is by the same definition *also* in Earth orbit. It's quite possible to orbit both - an orbit around the Moon looks like some weird spiral from the POV of the Earth.
That's why we use the phrase "Beyond *Low* Earth Orbit" (BLEO) for this.
Apollo was never BEO.
Cheers, Martin
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#127
by
enkarha
on 09 Dec, 2014 17:09
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I don't disagree. It just seems a strange thing to say, because from that point of view, no spacecraft has ever, for example, entered solar orbit. The body of reference, I think, could also be usefully defined as the one you're in the sphere of influence of. Of course it's all just semantics.
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#128
by
savuporo
on 09 Dec, 2014 17:40
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That's why we use the phrase "Beyond *Low* Earth Orbit" (BLEO) for this.
Apollo was never BEO.
AFAIK LRO or Chang'e-2 have never been called a BLEO craft, both were pretty universally called lunar orbiters.
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#129
by
A_M_Swallow
on 09 Dec, 2014 17:52
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The point I think Jim was making is that Mars is Beyond Earth Orbit (BEO) so a Mars Transfer Vehicle has to be a BEO spacecraft.
Orion like Apollo can take people to lunar orbit but not to Mars orbit. So Orion is only a Beyond Low Earth Orbit (BLEO) spacecraft, it is not a BEO spacecraft.
NASA will have to build a different spacecraft to go to Mars.
We are just not talking semantics but very very large sums of money.
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#130
by
MP99
on 09 Dec, 2014 18:13
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I don't disagree. It just seems a strange thing to say, because from that point of view, no spacecraft has ever, for example, entered solar orbit. The body of reference, I think, could also be usefully defined as the one you're in the sphere of influence of. Of course it's all just semantics.
If an object reaches Earth's escape velocity, then it is no longer in orbit around the Earth.
The object will still feel the pull of the Earth, but this will be insufficient to pull it back.
This is the point where the object has a C3 energy of 0 km^2/S^2.
Cheers, Martin
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#131
by
MP99
on 09 Dec, 2014 18:22
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That's why we use the phrase "Beyond *Low* Earth Orbit" (BLEO) for this.
Apollo was never BEO.
AFAIK LRO or Chang'e-2 have never been called a BLEO craft, both were pretty universally called lunar orbiters.
I am a mammal, but rarely referred to as such. It's much more useful to refer to me as Human, and this is understood as included in the broader group mammal.
Similarly, a Lunar orbit is one of the set of things which constitute BLEO, as are MEO, HEO, GTO, GSO, EML, ESL, etc. And BEO (escaped).
(ESL 3, 4 & 5 may be stretching a point, but I believe technically do meet the strict definition.)
Cheers, Martin
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#132
by
Jim
on 09 Dec, 2014 18:35
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The point I think Jim was making is that Mars is Beyond Earth Orbit (BEO) so a Mars Transfer Vehicle has to be a BEO spacecraft.
No, the point I was making is that Orion is not designed for the Earth-Moon Lagrange points.
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#133
by
Proponent
on 09 Dec, 2014 18:58
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Orion is designed for a lunar-landing mission using the 1.5-launch Constellation architecture, where the lander performs LOI. Would its design differ much if it were intended to fly to and from L-points? Seems to me it wouldn't: it's got about the right delta-V and duration.
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#134
by
A_M_Swallow
on 09 Dec, 2014 21:49
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The point I think Jim was making is that Mars is Beyond Earth Orbit (BEO) so a Mars Transfer Vehicle has to be a BEO spacecraft.
No, the point I was making is that Orion is not designed for the Earth-Moon Lagrange points.
You are going to have to give a reason for Orion being unsuitable for the Earth-Moon Lagrange points. The delta-v to the points is less than the delta-v to Low Lunar Orbit. The Orion ECLSS lasts 21 days which is more than twice the 8 days a trip to EML-2 takes.
Ref:
http://forum.nasaspaceflight.com/index.php?topic=1337.90
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#135
by
Jim
on 10 Dec, 2014 01:18
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You are going to have to give a reason for Orion being unsuitable for the Earth-Moon Lagrange points. The delta-v to the points is less than the delta-v to Low Lunar Orbit. The Orion ECLSS lasts 21 days which is more than twice the 8 days a trip to EML-2 takes.
Quite the opposite, you have to prove that it is suitable and you have yet to do it.
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#136
by
enkarha
on 10 Dec, 2014 01:28
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Quite the opposite, you have to prove that it is suitable and you have yet to do it.
No, the point I was making is that Orion is not designed for the Earth-Moon Lagrange points.
LockMart certainly aren't saying that with documents like this (pdf):
http://www.lockheedmartin.com/content/dam/lockheed/data/space/documents/orion/LMFarsideWhitepaperFinal.pdfGerst's talked about thistoo, and Boeing's proposed L-point gateways since 2006, and never have I heard mentioned any incapability that Orion might have in its ability to get to and stay at and return from an L-point.
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#137
by
Endeavour_01
on 10 Dec, 2014 02:14
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#138
by
redliox
on 13 Dec, 2014 09:14
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Here is another paper that shows Orion is perfect viable for EMLP missions.
http://www.spacepropulsion.org/uploads/2/5/3/9/25392309/spaceaccess2014-25.pdf
That paper definitely shows SLS 1b, if not the SLS 1 version, is full of potential. Regarding Orion, it would be able to visit any of the Lunar LaGrange points along with lunar orbit, so I differ with Jim on that. However, by visit I mean so long as it's within it's 20-some-day capacity. For a stay a month or longer augmentation would definitely be needed, and likewise for a hypothetical visit to the Earth-Sun LaGrange points along with Mars and the asteroids. Cislunar space, or more poetically "The Moon", is literally Orion's limit...solo at least.
What is the total delta-V capacity of Orion, or specifically what ESA is building for its service module? The math behind that would state Orion's true limit beyond solely life support supplies. I am very curious to compare what Orion can do with the needs of Mars.
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#139
by
Jim
on 13 Dec, 2014 12:49
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It is not a question of propulsion. Where is the documentation that states that Orion is designed for the environment in those locations?