Elbmek

Sorry, this is cut and paste. There is nothing really I could think to add that wasn't already printed:

NASA Study Provides Next Step to Establishing Lunar Outpost HOUSTON -- NASA engineers and scientists completed a milestone review June 20 that will help determine the systems needed to return humans to the moon and establish a lunar outpost.

The three-day Lunar Capability Concept Review capped a nine-month study led by the Exploration Systems Mission Directorate at NASA Headquarters in Washington that incorporated science and exploration objectives earlier developed by representatives of 14 countries as part of the Global Exploration Strategy.

The study looked at possible lunar mission scenarios and compared them to the capabilities of the emerging Ares V heavy lift launch vehicle and the Altair lunar lander design concepts. This review of those findings, led by the Constellation Program Office at NASA's Johnson Space Center in Houston, established all the technical parameters that will be needed to begin Phase A, the first phase in preparing vehicle requirements.

"We confirmed that Constellation's conceptual designs for both Ares V and Altair will enable us to land astronauts and cargo anywhere on the moon and to build an outpost supporting widespread exploration of the lunar surface," said Jeff Hanley, Constellation Program manager at Johnson. "This extensive review proves we are ready for the next phase: taking these concepts and moving forward to establish mature requirements."

According to Hanley, the study bears out the strength of the initial concepts showing the vehicles can be built and delivered in time to return humans to the moon by 2020.

The review also reinforced the key role of international partnerships and industry collaboration to developing the lunar surface systems for human missions to the moon.

Phase A begins the process of defining the vehicle and element requirements. During this phase, the Ares V and Altair Project teams will take what was learned from the Lunar Capability Concept Review and baseline the needs for lunar missions, establish the design needs and determine plans for advancing the technologies needed to be successful. Phase A will culminate in a Systems Requirements Review for NASA's lunar transportation architecture, tentatively planned for 2010.

The review refined early configurations of the Ares V rocket to ensure its capability to deliver the Altair lunar lander, four astronauts and cargo anywhere on the moon and return the crew to Earth at any time. To accomplish those objectives, the current configuration of the Ares V will use six RS-68B liquid oxygen and liquid hydrogen engines on a core stage along with two five-and-one-half segment solid propellant rocket boosters, which are a direct evolution from the first stage of the Ares I rocket. The Ares V upper stage will propel the Orion crew capsule and Altair to the moon using the same J-2X engine as the Ares I crew launch vehicle. The Ares V will stand about 381 feet tall and be able to send more than 156,600 pounds of cargo and components into orbit to the moon, and later to Mars or other destinations.

Altair will be capable of landing four astronauts anywhere on the moon, providing life support and a base for the first week-long surface exploration missions, and returning the crew to the Orion spacecraft for the ride home to Earth. A variant of the lunar lander will serve as an autonomous cargo carrier, taking modular outpost components, lunar rovers, and scientific equipment to the moon's surface.

The formal decision to start Phase A will be taken to NASA's leaders before the end of this year.

The Constellation Program Office at Johnson has the responsibility for developing the next human space transportation system that will be used to extend a human presence throughout the solar system. The program includes multiple project offices and technical teams at all ten NASA centers and at contract organizations around the nation. The Orion Project and Altair Project also are led from Johnson. The Ares Project Office at NASA's Marshall Space Flight Center in Huntsville, Ala., leads the design and development of the Ares I rocket and Ares V cargo launch vehicle. The Ground Operations Project at NASA's Kennedy Space Center in Florida will handle ground and launch operations for the vehicles.

For information about NASA's Constellation Program, visit:


NASA - Constellation

Parihaka

That's a BIG call. Putting aside free or near-free return, how are they going to deal with farside communications? What orbits will they establish for the Orion to compensate for a disabled Altair which can't manouver properly? How do you plan a descent into truly mountainous regions when steep descents use so much fuel? The whole process is going to be fascinating, but this suggests a seachange in NASA's attitudes from the seventies in that they seem far more willing to hang the astronauts out on a limb.

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Yet, in holding scientific research and discovery in respect, as we should, we must also be alert to the equal and opposite danger that public policy could itself become the captive of a scientifictechnological elite.

Dwight D. Eisenhower, 1961

Elbmek

Satellite comms, same as on the earth. put sats on the poles and bingo!

glyn

Er, 'Bingo' is aviation talk for a low fuel state, and Harry mentioned that in his piece.

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Semper in excretum. Solum profunda variat.

Elbmek

As I am not a colonial Glyn. For the uninitiated it simply means "solved"

Parihaka

And with much the same problem. Broadcasting major amounts of real-time data over the distance between Moon and Earth requires significant amps: therefore a set of geosync satellites to handle local lunar comms between various parties and stations, and a main station lunar-surface-based transmitter to broadcast to a further set of geosync earth-orbit satellites for relay to earth. No small feat in itself and a nightmare during solar flares.

And this is just so people can talk to each other. Four men at a time in some of the most geologically interesting and therefore most difficult terrain the moon has to offer is as I've already pointed out fraught with danger: building bases in those areas for long term mineral exploitation is a whole new game.

Parihaka

Think about it matey, how do you keep a satellite above the pole? You can only have geostationary satellites within a narrow band above the equator, they have to fall at the speed of rotation of the earth remember.

gunnut

I have a question, is it possible to have a geosynchronous, or in this case, lunarsynchronous satellite? It probably is but I just have a hard time imagining it.

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Elbmek

I suppose so yes. Why not?

ArmchairGeneral

Geosynchronous certainly, just have it sit above the equator at the distance where the orbital period is 24 hours, approximately 22,000 mi. We've got plenty of sats that do it. Lunarsynchronous would probably be a bit higher, give the very slow rotation of the moon. Although its lesser mass would make up for that in part.

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dalem

Good point made here:

We're IN a Lunarsynchronous orbit right now.

So you'd need at least two sats for 100% comms availability to all points Lunar. I don't know what the optimal number would be, but Hell's bells, it's not like such sats are too expensive. In 50 years I want people complaining about the amount of space junk in Lunar orbit too!

-dale

ArmchairGeneral

Well duh.

Parihaka

It's been ages since I read up on this stuff so pardon me if I make mistakes, but for a far-side mission at least 3 lunar geostationary (not geosynchronous as I said earlier) satellites would be required. I remember a paper Harrison Schmidt wrote when he was arguing for an Apollo 17 far-side landing, and IIRC he settled on a 3 satellite configuration. Obviously for long term exploration far more redundancy would be required, probably by a factor of 3 or 4.
I still haven't got my head around the high fuel usage for landings in mountainous terrain and more than 15 degrees off the lunar equator, I guess 3 or 4 Ares launches per mission in the initial stages would be the easiest if somewhat expensive option.

Parihaka

Cool, just found this animation on libration

andy2023

that's realy cool