Next one, please.

FIGURE 203

I want to talk just a minute about communication capabilities in space. Here, we have the calendar year on the bottom and then the time required for a television picture transmission on the vertical

scale.

Now, that is a nonlinear scale, so it is a logarithmic scale. You have to read it quite closely.

The television picture we get at home has 10 to the sixth power. or 1 million bits of information. It is composed of 1 million pulses. We use this example to indicate the time of transmission.

For example, a television picture from Mars would take on the order of a couple of weeks, right now. Using all the technology that we know right now, that we can put into use, and these are shown by the steps the year they would apply, the red being to the spacecraft, the white being to ground devices. This says that television pictures from Mars would stabilize in about 1969 at somewhat less than 1 minute transmission time.

With television pictures from Pluto, we would hope to do no better than a few days. That is the length of time for the picture-not the length of time for the transmission-and as an interesting comparison, Alpha Centauri, which is the nearest star outside our solar system, is 4 light years away, but it would take, in addition, 14 years to get a television picture through.

In other words, from the time the picture was sent from Alpha Centauri, would take 4 years for the initial portion of the message to get back here and would take 14 more years for the end of the message to get back here.

Mr. KARTH. Not worried too much about that one, are we, Doctor?

Dr. KELLEY. No, I'm just using, for an example, this comparison. We think Pluto is bad enough.

You see, if we get into reentry situations where the whole reentry might be over in a couple of minutes, obviously, taking a couple of days to transmit the picture is ridiculous, because the device has destroyed itself before the picture gets back.

This is illustrative, I would say, the exhaustion of our technology right now, as we see it.

We have to do something new and to do something different, if we are going to improve on the situation.

Next one, please (fig. 107, p. 1943).

One of the areas of capability increase and this, in fact, is included in the graph I just showed, is the area of ground antenna technology and one of the devices we are working on-one of the techniques we are working on, is the possible replacement of a large single antenna which you see on the left with the multiple array on the right. That is, getting nine smaller dishes, perhaps, to do the work of one larger dish. We really don't know how to do it yet. We see lots of payoff. For example, there is a lot more flexibility. You can be using the dishes to do different things at times. You don't need them all for deep space.

If one of the dishes goes down, you have a malfunction-we are still on the air, so to speak.

The next slide (fig. 206) shows one of the more striking factors, the straight economic payoff. You see the single dish.

This is the equivalent antenna system. We can relate the big dish to smaller dishes by the effective antenna size. You see on the bottom, the effective antenna system of either method, and on the vertical axis the cost. You see a crossover point at around 250 to 300 feet effective antenna size where single dish costs begin to skyrocket, whereas a multiple dish array has hopes of staying in bounds.

One of the more interesting ways of getting this information back, I mentioned it took-14 years to get a television picture back, but maybe you don't have to transmit the whole television picture every time. It seems to make sense to transfer or send back only the new information on each succeeding picture.

Now we begin to tie in the area of communications and data processing.

See, on the left, the television camera looking at the Moon and we painted two billboards on the Moon.

You see on the left-hand picture, the bottom billboard has only one thing different, and that's a triangle in the lower right-hand corner and sort of a square.

Our conventional techniques, right now, say when the picture changes, we transmit all the information back again, both the old and the new.

We are now very actively engaged in the video data processing business where we send back only the new information. We send back only the change in the billboard, but this takes computation. It takes investigation into how to use computers with television and so forth, and here now we begin to see a payoff for shortening the transmission time for television pictures.

Next one, please (fig. 208).

Our whole area of computation has been enhanced by the size of computers and this is coming about by miniaturization and microminiaturization is the word we use now, microelectronics.

Here, as a function of years, you can see the trend; talking about a device now which has a specific function in 1957 it would take 1 cubic foot and weigh-if you look over in the right scale, 150 pounds.

Again, this is a nonlinear scale, so you have to look closely. You see now we are coming down the curve and we are getting smaller and smaller.

If we get much smaller we are going to have to work that much harder. I suppose there is a limit as to how small we can get, eventually anyway; but we are beginning now to get down into very small

devices but

Next one, please (fig. 209).

That's only half the story.

After you get them small, what do you do with them?
How do you make them more flexible?

How do you adapt them to your need?

A computer is not a computer any more than electronics is electronics. You have different needs and different requirements.

Here you have the trend in computer memory and speed. These are the two factors or parameters by which we measure computers.

The left-hand vertical scale is the number of bits and it takes so many bits to make a word or message, depending on the computer and the bottom one is the speed of access, so these are two very important parameters.

You see, where the lurid green color is, where we are on present core memories. Then you see an area, present core developments. Now, you see on the two tails the push by various other agencies. The future semiconductor devices are useful to people who have interest in large numbers of bits at fairly conservative speeds. This might be routine data processing, intelligence information, and so forth.

Other Government agencies are working over in that area, called tunnel diodes.

Here, they are not so much interested in the number of bits but are interested in the speed. Something like an anti-ICBM. You'd want to be over there.