Author Topic: Space detection tech in 1960s.  (Read 5304 times)

Offline fossil1999

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Space detection tech in 1960s.
« on: 02/16/2017 11:57 am »
Hi everyone, I am new here.
First and foremost,  if I am posting this in the wrong place, I would be grateful if you showed me where this could go.
I thought about asking on an astronomy forum, but they seem to deal with amateur astronomy. And my question is related to the apollo missions. 

I am curious as to the level of radio and radar, etc, technology available to the Americans and the Soviets in the 1960s. I believe that by the late 50s, both sides could receive  radar echos from venus? How would this translate into detection capability, keeping an eye on a spacecraft in lunar orbit? I know that nowadays,  nothing that goes on in space can be hidden,  but what about back then?

Many thanks.

Offline Jim

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Re: Space detection tech in 1960s.
« Reply #1 on: 02/16/2017 01:49 pm »
How would this translate into detection capability, keeping an eye on a spacecraft in lunar orbit? I know that nowadays,  nothing that goes on in space can be hidden,  but what about back then?


Not true about nothing that goes on in space can be hidden.   There are very few space surveillance radars and assets.  Spacecraft can maneuver and get lost.  Even in LEO.  We lose spacecraft when they don't maneuver as expected and it take awhile to find them.

Offline envy887

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Re: Space detection tech in 1960s.
« Reply #2 on: 02/16/2017 02:58 pm »
Not sure about radar, but the Apollo missions were extensively tracked by telescope, even by amateurs. There's a lot of info online, but here is one pretty descriptive article.

http://pages.astronomy.ua.edu/keel/space/apollo.html

Offline fossil1999

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Re: Space detection tech in 1960s.
« Reply #3 on: 02/16/2017 03:08 pm »
Interesting.  :)

A relative of mine believes that no manned craft has gone beyond LEO.

Obviously there is uncountable evidence saying otherwise,  but I am searching for info to counter a specific argument that she used, regarding the apollo missions:
The Saturn V launched, and the astronauts spent all their time in a capsule, in LEO, that detached from the Saturn V without anyone noticing. When the 'mission' was over, they simply de-orbited.  ???

I can poke huge holes in that(radio signal tracking, CM re-entery speeds, etc), but I would like to know if a large component (the Apollo CM in this case) could ever separate from the main rocket (wrong terminology? ) and hide in LEO without the public and soviets noticing?

As I was writing, envy887 replied with what I was looking for.   :D
Thank you!
So in the case of the apollo missions, due to amateur (and soviet) scrutiny,  no space shenanigans could have been possibly hidden? No windows of opportunity?

Offline Rei

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Re: Space detection tech in 1960s.
« Reply #4 on: 02/16/2017 03:28 pm »
Venus at closest approach: 38m km
Moon average distance: ~380k km.
Attenuation difference: ~10000x

Cross section of Venus: 1,15e14 mē
Apollo (CSM + LM) cross section: <110 mē
Cross section difference: ~1e12x

Required dBZ difference: 90

Planets are far, but they're very big  :)

Offline envy887

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Re: Space detection tech in 1960s.
« Reply #5 on: 02/16/2017 04:38 pm »
But why? Going to LEO and NOT to the moon makes no sense at all. Once you go down the wacko road, you have to go all the way...

Offline Jim

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Re: Space detection tech in 1960s.
« Reply #6 on: 02/16/2017 05:01 pm »
Interesting.  :)

So in the case of the apollo missions, due to amateur (and soviet) scrutiny,  no space shenanigans could have been possibly hidden? No windows of opportunity?

No, that is not a valid conclusion.  The  amateur scrutiny was possible because the trajectory was know and there was no attempt at "cloaking" or hiding the spacecraft.

It would be very easy to do some shenanigans

Offline Jim

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Re: Space detection tech in 1960s.
« Reply #7 on: 02/16/2017 05:02 pm »
but I would like to know if a large component (the Apollo CM in this case) could ever separate from the main rocket (wrong terminology? ) and hide in LEO without the public and soviets noticing?


It could be done

Offline whitelancer64

Re: Space detection tech in 1960s.
« Reply #8 on: 02/16/2017 05:09 pm »
Interesting.  :)

A relative of mine believes that no manned craft has gone beyond LEO.
*snip*
So in the case of the apollo missions, due to amateur (and soviet) scrutiny,  no space shenanigans could have been possibly hidden? No windows of opportunity?

WRT Apollo, no, there is no chance of shenanigans at all. Jodrell Bank Radio Telescope in England could detect the change in velocity from urine dumps - by precisely measuring doppler shifts in the radio signals they'd have known if they were flying away from the Earth towards the Moon, or not, and the speed at which they were traveling. It's safe to presume the Soviets had similar capacities at the time.
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Offline Jim

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Re: Space detection tech in 1960s.
« Reply #9 on: 02/16/2017 05:32 pm »

WRT Apollo, no, there is no chance of shenanigans at all. Jodrell Bank Radio Telescope in England could detect the change in velocity from urine dumps - by precisely measuring doppler shifts in the radio signals they'd have known if they were flying away from the Earth towards the Moon, or not, and the speed at which they were traveling. It's safe to presume the Soviets had similar capacities at the time.

Huh?  Quite wrong.  So what if they could track a transmitting spacecraft.  If there were shenanigans, there would be no transmitting from another spacecraft. 

The point is that it is possible to hide a spacecraft.

Offline meberbs

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Re: Space detection tech in 1960s.
« Reply #10 on: 02/16/2017 05:48 pm »

WRT Apollo, no, there is no chance of shenanigans at all. Jodrell Bank Radio Telescope in England could detect the change in velocity from urine dumps - by precisely measuring doppler shifts in the radio signals they'd have known if they were flying away from the Earth towards the Moon, or not, and the speed at which they were traveling. It's safe to presume the Soviets had similar capacities at the time.

Huh?  Quite wrong.  So what if they could track a transmitting spacecraft.  If there were shenanigans, there would be no transmitting from another spacecraft. 

The point is that it is possible to hide a spacecraft.
The intent of the question was whether or not it was possible that they had actually hidden the command module in LEO, not whether they could have done it if they had tried.

The tracking of the transmitting spacecraft in such detail shows that there really were humans aboard and the craft really went to the moon.

Offline fossil1999

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Re: Space detection tech in 1960s.
« Reply #11 on: 02/16/2017 05:49 pm »
Thank you everyone!  I think I have the answers I need.  :)

My conclusion:
As the trajectories in the apollo missions were known to anyone;  amateurs and professionals with telescopes and radio sets would have seen all the stage separations,  the trans lunar injection burn, and the LM landing, the ascent stage re-docking with the CSM, and the return to earth process, plus heard all the transmissions?
Basically everything aside from when the CSM was on the far side of the moon?

But why? Going to LEO and NOT to the moon makes no sense at all. Once you go down the wacko road, you have to go all the way...
Hehe, but the end of the wacko road in this case involves bribing 400,000 workers, plus their families.  ::)
Even my skeptical relative doubts that!
« Last Edit: 02/16/2017 05:52 pm by fossil1999 »

Offline gosnold

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Re: Space detection tech in 1960s.
« Reply #12 on: 02/16/2017 05:50 pm »
Venus at closest approach: 38m km
Moon average distance: ~380k km.
Attenuation difference: ~10000x

Attenuation goes as the square of the distance.

Also, to the overall point of this thread:

Offline fossil1999

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Re: Space detection tech in 1960s.
« Reply #13 on: 02/16/2017 05:53 pm »
Venus at closest approach: 38m km
Moon average distance: ~380k km.
Attenuation difference: ~10000x

Attenuation goes as the square of the distance.

Also, to the overall point of this thread:

I did not remember that xkcd comic, I love it!  ;D

Offline envy887

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Re: Space detection tech in 1960s.
« Reply #14 on: 02/16/2017 06:10 pm »
but I would like to know if a large component (the Apollo CM in this case) could ever separate from the main rocket (wrong terminology? ) and hide in LEO without the public and soviets noticing?


It could be done

That part could be done, but keeping the CM in LEO would require the SM too. So what was observed going to the lunar surface and back? The LM barely had the dv to go from LLO to the surface and back to LLO. Even stripped down it couldn't do LLO insertion and TEI.

Offline nicp

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Re: Space detection tech in 1960s.
« Reply #15 on: 02/16/2017 06:53 pm »
Attenuation goes by the square of distance. Attenuation of a reflected signal goes by the fourth power of distance. Well that's my understanding anyway, but I haven't studied telecommunications in over 30 years.
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Offline Jim

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Re: Space detection tech in 1960s.
« Reply #16 on: 02/16/2017 07:43 pm »

 the trans lunar injection burn, and the LM landing, the ascent stage re-docking with the CSM, and the return to earth process, plus heard all the transmissions?


Nobody saw these.  And all the transmissions were encrypted. 

I am not trying to debunk the actual landings, just the methodology you are using.

Offline kevin-rf

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Re: Space detection tech in 1960s.
« Reply #17 on: 02/16/2017 08:51 pm »
It is worth noting with high certainty that while no shenanigans happened during the manned lunar program, some shenanigans may have (probably) happened with some DOD programs.

Specifically look up Misty and Prowler. They are rumored to have been hidden by the use of decoys and some sort of sun screen.

https://en.wikipedia.org/wiki/Prowler_(satellite)

https://en.wikipedia.org/wiki/Misty_(satellite)

Can't put my finger on the exact references, but many satellites have stayed attached to other satellites and possibly spent upper stages as secondary payloads. Blackstar would be your best bet.

Somewhere on the internet is a patent for a stealth sun shield: https://www.google.com/patents/US5345238

I think it is these and many other shenanigans that Jim is hinting at. He would most likely have to shoot us if he told us about the other shenanigans.
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Offline fossil1999

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Re: Space detection tech in 1960s.
« Reply #18 on: 02/16/2017 10:03 pm »
As I understand radar capabilities above, basically a radar dish able to get echos from venus would find a spacecraft in lunar orbit too small to detect an echo?


Reply #2, envy887 linked a website about tracking apollo, apparently listening in on the transmissions was possible?

I found comments on an article, that the transmissions from the moon were not encrypted, just multiplexed and compressed for efficiency,  which would make them gibberish if you did not know the algorithms?
http://blogs.discovermagazine.com/badastronomy/2009/09/28/lunar-eavesdropping/#.WKYtp5_LfqA


Suspiiicious shenanigans? You've given me a new subject to look into. 8)

Offline kevin-rf

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Re: Space detection tech in 1960s.
« Reply #19 on: 02/17/2017 12:28 am »
You might want to also look into bistatic radar. It is how the now decommissioned Space Fence operated for tracking objects in low Earth orbit. It does not quite work like you envision radar working. More like an electric eye blipping when satellites pass through it. Then based on the timing of the many passes over many days an orbit was worked out.

That was state of the art satellite tracking in the early 1960s. Shame they turned it off in 2013.
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Offline Arch Admiral

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Re: Space detection tech in 1960s.
« Reply #20 on: 02/18/2017 10:20 pm »
Actually, spacecraft were probably more tracked in the 1960s than they are now. There were three separate NASA networks run by Goddard, JSC, and JPL. The tiny Australian Capital Territory had antenna sites from all three of these, only a few miles apart but administratively totally separate. The Air Force had a fourth network to deal with classified satellites and the CIA Directorate of Science and Technology had a 5th "black" network tracking Soviet spacecraft. Both USAF and USN operated a variety of aircraft,balloons, and ships that tracked missiles and spacecraft from both sides.

On the other side, the USSR had only a single tracking net run by the Rocket Force which handled both military and civilian spacecraft. But the individual tracking stations were much larger and had many antennas. Some of these were certainly used to track US spacecraft. This system was (and still is) limited because there were no stations outside the USSR. For Moon missions they sometimes put a tracking ship in Havana harbor to get continuous coverage.

The UK had two notable free-lance tracking organizations at Jodrell Bank and Kettering Grammar School. Jodrell Bank scored a coup by intercepting and publishing the Luna 9 photographs before the Soviets released them.

So a typical spacecraft near the Moon would be monitored continuously be at least two networks, Ours and Theirs.

For objects without a transmitter or transponder, tracking could only be by radar (skin-tracking) and the 4th-power law limited range to the immediate vicinity of Earth. The Naval Space Surveillance System (Space Fence) was the main active sensor in the US, and the Soviets had a similar system called OS.

So in the 60s nothing could be launched in secret. Since the 80s this may no longer be true. But I have trouble understanding how a stealth spy satellite can remain invisible in radar, thermal IR, and reflected sunlight simultaneously, and still point antennas or telescopes downward to do its work. The physics don't add up.

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