A FAIR DEBATE

[Glom]

But who wrote those poems?

[Bob B.]

I've been to Bob's website to try to figure some of it out but I'm at a total loss. I would probably need hmmm.... to STUDY orbital mechanics to understand it.

There was a time I didn't know much about it either.  Although I have an engineering degree, I consider my physics education to be pretty rudimentary (six credit hours in college as I recall, and I wasn't especially interested in it or did particularly well).  But when I decided to apply my talents to a hobby that really interested me - space flight - I was determined to learn.  I've been able to absorb it little by little over what has now been about 17 years since I first started to study it.  One certainly needs an aptitude for math and science to fully understand orbital mechanics, but just as important is perseverance.

BTW Bob your website is really cool. I showed it to my physics class a couple of years ago

Thank you.  I hope your physics class got something out of it.


BTW, I just put on line my new page about Interplanetary Flight.  I intend to add a couple more parts:  Gravity Assist Trajectories and Lunar Trajectories.

[twik]

OK, DAKDAK, you proposed a debate. That means you have the floor to start.

But simply making a list of points is not debating. Saying "the computer wouldn't work" or "the orbital mechanics were wrong" is not debating. If I say "the Moon is made of green cheese" in a debate, I have to follow that with "and here's why we know that".

If you want to debate people, please go ahead and do so. But if you planned on merely making these pronouncements, and having everyone go "ooooh, he's right!", I think you misunderstood what debating really means.

[nomuse]

The AGC was actually more sophisticated in many ways than many embedded systems used today. It actually had a tasking operating system, for example, rather than a simple executive loop performing a fixed sequence of operations. 4 kB RAM (2k 16-bit words, actually, with one bit set aside for parity) and 72 kB RAM (36k words) or program memory is pretty typical for small embedded processors now.

For another example...
http://dmitry.co/index.php?p=./04.Thoughts/08.%20uM0

An ARM emulator (specifically a Cortex-M0, a small 32-bit embedded processor) written for the AVR (an even smaller 8-bit embedded processor). Built to 3464 bytes total program memory on my system, and only 61 bytes of RAM required by the VM. Built for a modern 8-bit microcontroller with 8 KB program space and 256 bytes of RAM.

The AGC didn't even have a text interface...user interaction was via numeric commands and readouts, toggle switches, etc. It's not at all unbelievable that it did what was claimed...particularly since, as mentioned, there's enough information available about it to build replicas and simulators.

I just wanted to jump up and say "AVR freak here!"

I think it is informative that an 8-bit chip running at 16MHz, with under 64K of program space, can not only run a quad-rotor UAV autonomously, station-keeping and attitude holding in real time, and not only run both inertial nav and GPS to fly either under command or autonomously from waypoint to waypoint, but it can do this with enough accuracy to be used inside a lecture hall full of people.

(Well, okay...Cris doesn't try to run the GPS waypointing inside, but it is still impressive to see that large a machine hovering in place to an accuracy of a few cm of slippage, all running on one little arduino-compatible).

[Echnaton]

(Well, okay...Cris doesn't try to run the GPS waypointing inside, but it is still impressive to see that large a machine hovering in place to an accuracy of a few cm of slippage, all running on one little arduino-compatible).

It is sad that the simple joy of seeing something so remarkable yet simple and understanding its elegance is lost on some people.

[peter eldergill]

Bob, I recall seeing an animated orbit on your website before, but can't seem to find it again. Am I thinking of your website or am I thinking of another? If it's there, can you point me in the right direction.

Pete

[ka9q]

Yes, I made the mistake of looking at some of his videos a couple months ago. What a nutcase. "Intentional incoherence's" left by the Apollo engineers as clues to show how fake the program was. He's supposed to be a computer engineer on top of it all.

Yeah. The strangest thing is that he professes a love for science, yet he really does seem to honestly believe the nonsense he spouts.

[ka9q]

BTW, I just put on line my new page about Interplanetary Flight.

Good page. One minor nit: you say that the heliocentric ecliptic coordinate system isn't quite inertial because of the precession of the earth's axis. Actually that's the reason that the earth-centered equatorial coordinate system isn't inertial; that's where you see references to epochs like B1950 and J2000.

The ecliptic plane is much more stable than the earth's equatorial plane, but it too wobbles a tiny bit due to out-of-plane perturbations from the other planets, mainly Jupiter. If you want a truly inertial coordinate system for interplanetary travel, use the barycentric invariant plane of the solar system. The origin is at the solar system's center of mass, dominated by the sun, of course. The reference plane is normal to the total angular momentum vector of the entire solar system, dominated by Jupiter's angular momentum but the other planets do contribute some tiny bits. Technically even the Kuiper Belt and the Oort cloud would have to be included, and since it contains many undiscovered objects the invariant plane is still somewhat ill defined. But probably not by much.

 I'm not sure what you use as a longitude reference, probably the location of some distant quasar at the edge of the visible universe.

[Bob B.]

Bob, I recall seeing an animated orbit on your website before, but can't seem to find it again. Am I thinking of your website or am I thinking of another? If it's there, can you point me in the right direction.

The animation is from a separate webpage that is just a collection of Apollo related stuff that I've done.  Here's the link:

http://www.braeunig.us/apollo/

[Bob B.]

Good page. One minor nit: you say that the heliocentric ecliptic coordinate system isn't quite inertial because of the precession of the earth's axis. Actually that's the reason that the earth-centered equatorial coordinate system isn't inertial; that's where you see references to epochs like B1950 and J2000.

The heliocentric-ecliptic system is also affected by precession because zero degrees longitude in this system is defined as the direction of the vernal equinox, just like it is in the geocentric-equatorial system.  Precession causes the line of equinoxes to continually change, therefore both coordinate systems are affected.

[ka9q]

The heliocentric-ecliptic system is also affected by precession because zero degrees longitude in this system is defined as the direction of the vernal equinox, just like it is in the geocentric-equatorial system.  Precession causes the line of equinoxes to continually change, therefore both coordinate systems are affected.

Ah, I see. The ecliptic plane itself remains relatively stable but the defined coordinate axes rotate within it.

I suspect that the way to get a really stable coordinate system is to define one by reference to the most distant radio sources we can detect.

[Bob B.]

Ah, I see. The ecliptic plane itself remains relatively stable but the defined coordinate axes rotate within it.

That's correct.  If you look at a star map you'll see that the points where the ecliptic and equatorial planes cross are defined 0^o and 180^o longitude in both planes.  Precession causes the equatorial plane to move, therefore these crossing points change position.  So, although the ecliptic plane remains fixed, the direction of the zero longitude point changes over time.

(Edit)  Of course, in the geocentric-equatorial system, celestial positions are usually given in hours of right ascension and degrees declination.  This makes the direction of the equinoxes in the equatorial plane 0 and 12 hours right ascension rather than 0^o and 180^o longitude.  Same thing though, just a different name.

[ineluki]

"Common sense" would just say go in a straight line -- none of these time-wasting crazy curves 

Must be the same "common sense" that tells DAKDAK
- to start his "fair debate" by calling everyone else "extremely biased"
- insult those that disagree with him to be "too educated"
- that "I say so" is a valid claim outside kindergarten

[Laurel]

"Common sense" would just say go in a straight line -- none of these time-wasting crazy curves 

Must be the same "common sense" that tells DAKDAK
- to start his "fair debate" by calling everyone else "extremely biased"
- insult those that disagree with him to be "too educated"
- that "I say so" is a valid claim outside kindergarten

- to complain about being called a seagull and then spend the next few days acting like a seagull

[raven]

"Common sense" would just say go in a straight line -- none of these time-wasting crazy curves 

Must be the same "common sense" that tells DAKDAK
- to start his "fair debate" by calling everyone else "extremely biased"
- insult those that disagree with him to be "too educated"
- that "I say so" is a valid claim outside kindergarten

- to complain about being called a seagull and then spend the next few days acting like a seagull

- to say education is useless on an extremely sophisticated international computer network.