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#140
by
Tomness
on 13 Dec, 2014 14:08
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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?
Then that statement begs the question of why are we building SLS/Orion if its not going deep space missions. I understand no money for those missions so its not built for it. People want steak (Constellation Ares V/ Orion - Saturn V) and they will have Romen Noodles (SLS/Orion) if at all.
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#141
by
savuporo
on 13 Dec, 2014 16:22
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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?
Then that statement begs the question of why are we building SLS/Orion if its not going deep space missions.
There are all sorts of different kinds of "deep space". Messenger needed a specialized radiator design to protect it in intense solar flux, Juno needs a specific radiation protection design for Jupiter orbit. Solar arrays and radiators need to be sized differently for spacecraft orbiting Venus and Mars. Communication and navigation subsystems for different deep space destinations are necessarily different.
The idea that you can take one spacecraft and send it everywhere in solar system is not realistic.
Common buses, subsystems can be shared in some cases, but for a new destination you are still redesigning a different spacecraft.
In specific case, i'm pretty sure lunar orbit environment and EML points are similar enough environments that spacecraft don't need different configurations and Orion would be able to transfer between those just fine, just as other spacecraft have done before it.
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#142
by
A_M_Swallow
on 13 Dec, 2014 19:09
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The Orion has been redesigned so many times that the high level requirements of the current design probably have not been published.
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#143
by
pathfinder_01
on 13 Dec, 2014 19:53
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Then that statement begs the question of why are we building SLS/Orion if its not going deep space missions. I understand no money for those missions so its not built for it. People want steak (Constellation Ares V/ Orion - Saturn V) and they will have Romen Noodles (SLS/Orion) if at all.
I am no expert but I suspect the problems are as follows:
1. The gravitational field at the L points is a bit different from either lunar orbit or LEO. New techniques for docking may have to be developed.
2. Assuming 4 days to the L point and 4 days back that leaves only about 13 days it could spend there. Not much time. It would require an space station to get any long term mission(and none are currently being built) . And this assumes they didn’t cut back to help Orion meet it’s weight.
3. The radiation shielding maybe too thin for any long term mission and I suspect way too thin to deal with a solar flare and not have to leave. It maybe good enough for travel to the moon, maybe some defense while you turn around and head back home due to flare but not good enough by itself. Apollo’s plan for solar flare was to abandon mission. The longer the mission the more risk for solar flare.
4. If you pre-place a lander at the L points you have to factor in how long it is going to take to get to and from the moon. Granted it in theory should have the ability to last 6 months without an crew but again that could be compromised for weight reasons. An lander would have to be built even lighter than the capsule which could making caring enough shielding for a long term mission an problem and an danger should the crew be on the moon when an solar flare hits(it won’t be able to get back to the capsule as fast as Apollo. ). Plans that use a slightly modified lunar lander as a temporary moon base may be a bit unrealistic or much too expensive to engineer. An long term lunar mission might need something more substantial for habitation.
The trouble is the term deep space is kinda nebulous. An 6 month ability to stay in space won't get you to mars. Maybe an asteroid mission or lunar one.
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#144
by
jgoldader
on 14 Dec, 2014 13:04
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Just venting here...
Orion is a transport, from Earth to space and back. It's not like the shuttle, which could carry along "stuff to do in space" in the cargo bay. Without extra elements like hab modules (undesigned and unfunded) or deep space stations/outposts (undesigned and unfunded) Orion is severely limited in what it can do. The asteroid mission is make-work, the most exploration the thing can do, and it needs the help of the robotic part (undesigned and unfunded) to do even that.
I remember when there was going to be the space tug to work with the shuttle to move satellites from their original orbits down to the shuttle's LEO for repair and such. Shuttle did fine without it, but it was an important piece of enabling technology that never happened. The difference between shuttle and Orion is that shuttle had a cargo bay and could bring up stuff to do, and so was very successful without the space tug; and Orion cannot do much without the missing supporting hardware.
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#145
by
MP99
on 14 Dec, 2014 20:39
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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?
It's listed in the Design Reference Missions.
cheers, Martin
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#146
by
sdsds
on 15 Dec, 2014 04:43
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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?
It's listed in the Design Reference Missions.
I think it is merely a matter of nomenclature. Orion was not designed for lunar Lagrange or DRO missions. For MPCV this ability was a requirement. Then NASA chose Orion as the basis MPCV....
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#147
by
MP99
on 15 Dec, 2014 06:46
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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?
It's listed in the Design Reference Missions.
I think it is merely a matter of nomenclature. Orion was not designed for lunar Lagrange or DRO missions. For MPCV this ability was a requirement. Then NASA chose Orion as the basis MPCV....
There has been several years of development of MPCV since then.
I'd be interested to understand any substantial difference between the environmental requirements of DRO (which is in MPCV's early manifest) and EML.
The only thing that occurs to me is eclipse / LOS at EML2. TBH, I didn't think this was such an issue with spacecraft travelling in a halo orbit around the point itself.
Cheers, Martin
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#148
by
sunbingfa
on 15 Dec, 2014 19:37
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I think no doubt we are all extremely disappointed to hear delay after delay.
But just ask the question: what other options does NASA have for human spaceflight?
Certainly not focus on LEO.
Moon base? Maybe, but what can we really learn from that? because go to Mars, we can only carry much less resource than what is possible to put on the moon, and landing is also different.
We still don't have the capability/spacecraft to live in deep space for 1-2 years, we still don't know how to get to mars with significant amount of payload.
While this ARM seems strange (why not directly to a near earth asteroid?), it still helps to develop some technologies such as more powerful deep space propulsion, which can cut the time of the trip to Mars.
And more practically, NASA has to find something to do with SLS and Orion between now and when we are ready to Mars. Otherwise, basically we are waiting for Spacex to make the MCT functional.........
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#149
by
Chris Bergin
on 17 Dec, 2014 14:59
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NASA will host a media teleconference at 4 p.m. EST today during which agency officials will discuss and answer questions on the selection of an Asteroid Redirect Mission concept.
The mission is to retrieve an asteroid mass and redirect it into lunar orbit, where astronauts will explore it in the 2020s. The mission will test a number of new capabilities needed for future human deep space expeditions, including to Mars.
Participants for the media teleconference are:
Robert Lightfoot, NASA associate administrator
Michele Gates, program director, NASA’s Asteroid Redirect Mission
Lindley Johnson, program executive, NASA’s Near Earth Object Program
Audio of the media teleconference will stream live on NASA's website at:
http://www.nasa.gov/newsaudio
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#150
by
enkarha
on 17 Dec, 2014 20:40
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Updates from the conference:
Trent Perotto opens, hands it over to Assoc. Administrator Robert Lightfoot.
Meeting occurred yesterday, lots of information reviewed. Progress on both concepts reviewed through the risk reduction over the past few months. A decision was not made, some additional clarification was needed on some things. Apparently it's very close, and there are more commonalities than differences. A decision will take place beginning of next year- in "2 or 3 weeks" time. The mission concept review will occur near the end of February, and a launch date should be more solid at that time. The possible vehicles are Delta IV-H, Falcon Heavy, and SLS.
Option B is more complex, but demonstrates more extensible technologies, which are the main factors in decision.
Their funding from the Omnibus is fine to continue on the project.
Other notes: NASA needs to update their music selection. That was a very long elevator ride.
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#151
by
Chris Bergin
on 17 Dec, 2014 20:49
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