Author Topic: Apollo 18 and 19 Proposed landing sites  (Read 9005 times)

Offline ka9q

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #15 on: February 11, 2016, 06:10:56 PM »
As ka9q has pointed out their would certainly been improvements in electronics, since most of the 60's Apollo electronics were built on  RTL framework, stable but obsolete currently.
Not just RTL, but electromechanical relays. I haven't looked much at the Saturn V logic, but I've looked a lot at the CSM and LM. Although RTL is the basis of the AGC, it is hardly used elsewhere. Logic decisions are made mostly with combinations of mechanical switches, relays, diodes and discrete bipolar transistors. One-shots are frequently used for timing. (That's a circuit that, when activated, produces a pulse of a specified duration.)

Because switches and relays are mechanical and therefore unreliable, a lot of effort went into mitigating single failures. Several critical functions, e.g., SM Jettison, have two switches in parallel.

Nowadays these functions would be implemented totally differently. If I were designing the architecture, I'd dedicate a small microcontroller (or two or three, for redundancy) to each specific function, e.g., sequencing the parachutes or keeping the high gain antenna pointed at earth. Communication would be over shared or switched digital links, much like today's cars use Canbus, greatly reducing the amount of wiring. There'd still be plenty of room for a redundant bus or two in case one gets broken or shorted. Communications between modules (e.g., SM/CM, CM/LM) could be optical to simplify and improve the reliability of the connections. That would leave only electrical power, oxygen, water and possibly coolant that would require separate lines in a SM/CM umbilical.

Many controls would move to touch screen, but I would spend a considerable amount on human factors research in which the astronauts would be closely involved. I think a lot of present-day touch screens are very badly designed because nobody really pays attention to how they're used. I also think they go too far in moving everything to touch screens, probably to save money. Some functions should probably remain on dedicated mechanical switches and knobs because they're so frequently used, must be instantly accessible, or must be usable by feel when your eyes have to be elsewhere. A simple example is an audio volume control but I'm sure there are many others. But there's probably no need for dedicated switches that are used only once in a mission, and then only as part of a complete sequence (e.g., firing various pyros). Just have one big mechanical switch or button to serve as a crew "master arm" or "proceed" indication to the computer.

Lighting would be LED, of course. Not only are they much more efficient than incandescents, they're far more reliable.

All this means much lower power consumption than Apollo. So little that the thermal design would have to change, lest the cabin get as cold as it did on Apollo 13 with the power completely off.

In fact, it's an interesting question as to how little power you would really need to keep an Apollo-type spacecraft going in its cruise configuration. Most of it would probably go to the Environmental Control System for coolant pumps and oxygen fans, followed by communications depending on the required data rate (TV would take more than voice and telemetry).
« Last Edit: February 11, 2016, 06:14:14 PM by ka9q »

Offline Glom

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #16 on: February 11, 2016, 06:25:23 PM »



A20 was to have gone to Tycho (looking for a big black slab no doubt  :) )

I thought that was Clavius?

Offline bknight

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #17 on: February 11, 2016, 07:45:17 PM »



A20 was to have gone to Tycho (looking for a big black slab no doubt  :) )

I thought that was Clavius?
IIRC it was Tycho (TMA), but it has been over 50 years since I watched it.  They were based in Clavius.

EDIT: Spelling
« Last Edit: February 11, 2016, 07:49:28 PM by bknight »
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Offline Sus_pilot

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #18 on: February 12, 2016, 01:06:41 AM »




A20 was to have gone to Tycho (looking for a big black slab no doubt  :) )

I thought that was Clavius?
bknight has it.  Clavius Base, and they took a moon shuttle to Tycho. 

Offline smartcooky

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #19 on: February 12, 2016, 01:57:21 AM »



A20 was to have gone to Tycho (looking for a big black slab no doubt  :) )

I thought that was Clavius?


TMA stood for "Tycho Magnetic Anomaly"

Clavius Base was the fictional lunar settlement, and that concept and name has been used by a number of other science fiction writers in novels and short stories, including  Steven Baxter (Wheel of Ice), Larry Niven (Rainbow Mars)
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Offline Peter B

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #20 on: February 12, 2016, 07:38:49 AM »
Good additional information, as I didn't see the latter site.  I tend to agree with 18 and 19 being cancelled, since the hardware was built and paid for.  I'm not in the political ring and my voice as well as scientists didn't sway the opinion.
Who knows what may have happened.  It seems some of us as always looking back and asking what if.

I can see where you and Smartcooky are coming from with the cancellation of Apollos 18 and 19.

The thing is, though, that it came to a lot more than just having built and paid for the hardware. Politics was against NASA, and had been since Nixon's election. NASA's budget was eminently cuttable because there were so few votes at risk.

The next problem was the naivety of both NASA management and the science community they'd built up. I forget where I read about it, but apparently when scientists started writing in to Congress asking that NASA be given the money to run A18 and A19, the reply was something along the lines of You should have been writing these letters back in 1968.

In the case of NASA, they came up with an absurdly optimistic post-Apollo program that was going to dwarf the cost of Apollo - moon bases, trips to Mars, Earth-orbital space stations, Moon tugs, space shuttles. That NASA management blithely endorsed this and went to Congress to ask for the money suggests they didn't have a clue about the political realities of the world they were operating in - Jim Webb wasn't there to remind Congressmen about the skeletons in their closets he knew about in order to get budgets passed. And so what NASA was forced to do was scale back its plans, until out of that wish-list it was left with the shuttles. And IIRC Jay said that potential shuttle contractors said they weren't going to bid on its components unless they knew the Saturn V production line was shut down.

So NASA got stuck with the Shuttle instead of an ongoing Saturn V production line. And then, as their budget got cut even further, they had to constantly compromise the design, so that what they ended up with wasn't much like the original design that Max Faget was waving around in 1972.

The thing that gets me though, was the need for every thermal tile on the Orbiter to be a different shape. That must have been a logistical nightmare.

Offline ka9q

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #21 on: February 12, 2016, 08:52:51 AM »
The thing that gets me though, was the need for every thermal tile on the Orbiter to be a different shape. That must have been a logistical nightmare.
By itself that wouldn't have been so bad. There are lots of unique parts in any complex system, and even in the 1970s and 80s we had early computer-controlled machines to make them.

The real problem, in my opinion, is that so many of these tiles kept falling off or were damaged enough to require replacement after every mission.

And then you had the nominally-reusable SSMEs that had to be torn down, overhauled and rebuilt after every flight.

And the nominally reusable SRBs that were little more than empty steel tubes when they were recovered.

And the ET that was thrown away during each flight. I remember some plans for those tanks that involved taking them just a wee bit further into orbit so they could be used as structures for all sorts of ambitious undertakings.

Offline bknight

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #22 on: February 12, 2016, 09:00:37 AM »
The thing that gets me though, was the need for every thermal tile on the Orbiter to be a different shape. That must have been a logistical nightmare.
..

And then you had the nominally-reusable SSMEs that had to be torn down, overhauled and rebuilt after every flight.

And the nominally reusable SRBs that were little more than empty steel tubes when they were recovered.

And the ET that was thrown away during each flight. I remember some plans for those tanks that involved taking them just a wee bit further into orbit so they could be used as structures for all sorts of ambitious undertakings.
Yes the SSMEs took a lot of time out of the mission turn around with all the overhauling.
The ET's destruction in the Indian/Pacific ocean must have provided some fireworks.  I don't remember seeing any images of their re-entry.
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Offline Dalhousie

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Re: Apollo 18 and 19 Proposed landing sites
« Reply #23 on: February 14, 2016, 10:38:23 PM »



A20 was to have gone to Tycho (looking for a big black slab no doubt  :) )

I thought that was Clavius?


TMA stood for "Tycho Magnetic Anomaly"

Clavius Base was the fictional lunar settlement, and that concept and name has been used by a number of other science fiction writers in novels and short stories, including  Steven Baxter (Wheel of Ice), Larry Niven (Rainbow Mars)

Presumably in homage to Clarke (who fist mention Clavius as a settlement in "A fall of Moon dust"