What are these elements on ISS modules?

[wolverine84]

I'm wondering?. Antennas perhaps?.

 

[adrenalynn]

Definitely antennas. Helical or circular-polarized maybe. Docking nav antennas, maybe?

 

[wolverine84]

Hm, docking antennas on Soyuz/Progress are much much smaller, Those things are huge!. Sort of reminds of cell tower antennas. Could they be antennas sending telemetry data to satellites or centers on earth?

 

[SteveCNC]

to me they look similar to a radar unit used by police , perhaps it's part of a collision detection system .

 

[MeteorWayne]

ROFL, if they were a collision detection system, by the time it was detected, the ISS would be hit.

Get real!!!!

 

[SteveCNC]

ROFL, if they were a collision detection system, by the time it was detected, the ISS would be hit.

Get real!!!!

laugh all you want but they appear to be radar units covering a 360 degree section , possible uses would be during docking with other vessels manned or not for approach speed/distance and collision alert . Hopefully their delta-v won't be so high that impact is a problem hence the alert . I'm not aware of the ISS having a full working radar unit capable of tracking but this would be a cheap easy solution to guiding a remote in or something .

 

[MeteorWayne]

My point is that if that was they were for, by the time a collision would be detected, it would be 2 days late too to do anything about it. Like I said, get real!

I'm continually amazed by how little so many posters here understand about real physics, and the real world.

 

[SteveCNC]

I see well that wasn't the type of collision I was refferring to , I guess I assume too much from people here and should spell things out more clearly but in forums it seems like if you write too much then only your first paragraph gets read and then they hit reply . kinda a catch 22 so to speak , either way your misunderstood .

 

[MeteorWayne]

OK, can you state what you were trying to say?
Because your previous posts didn't really do that.

And BTW, I'd like to know what they are too!

MW

 

[SteveCNC]

If they are radar units similar to police units (look like maybe a little stronger) you might see in their rear window . Non directional just rear facing and they don't actually cover quite a 180 degree swath more like 120 but I would assume there are only 2 approach vectors for docking . Such a unit could feedback distance and delta-v of an approaching vessel during docking and it wouldn't take much to program in a collision alert signal should the approach window be violated . As for the vector of the approach I'm not sure how that is handled either but I would assume a variation of the ILS system most likely . That would be IMO the most reliable and cost effective solution to docking (I know dosen't sound like nasa but hey who knows) .

Anyway that's what they look like to me and if they are radar then I'm also sure they would be used for docking .

 

[MeteorWayne]

First of all, I have no idea what they are.

Docking is a reasonable idea.

Collision avoidance is a completely laughable concept. Physics...

 

[adrenalynn]

Omnidirectional radar antennas in police cars? Bwahahahahahaha! No.

Any circular polarization or helical quad will look like that. Many extremely directional Yagis will as well. It's entirely impossible to tell what band an antenna is when it's inside a housing like that, outside of saying that it's most likely VHF or higher. Hard enough to tell if the antenna is exposed. Quarter wave UHF or half wave SHF? Same size. Then you have to take into account where the antenna is loaded. And what about multiband antennas that are multiply loaded? A quad-band VHF/UHF/SHF is the same length as the upper bands of HF. And since you can't see the loading when it's inside a housing - you'll never know.

 

[wolverine84]

...I have send a e-mail to Nasa asking them what they are. I hope I'll get the answer in the next 6 months .

 

[MeteorWayne]

Good idea!! Let us know what you find out. I am researching it also trying to find out

 

[wolverine84]

Will do.

 

[duluthdave]

This one caught my interest, so I did a bit of research. As best I can tell, that's the UHF antenna installed on the Destiny module during STS-100. The antenna is used for communication during spacewalks and for station-shuttle communications.

http://www.shuttlepresskit.com/STS-100/eva14.htm
http://www.spaceref.com/iss/element.drawings.html

 

[wolverine84]

Woah!..this is great!. Thanks.

 

[SteveCNC]

This one caught my interest, so I did a bit of research. As best I can tell, that's the UHF antenna installed on the Destiny module during STS-100. The antenna is used for communication during spacewalks and for station-shuttle communications.

http://www.shuttlepresskit.com/STS-100/eva14.htm
http://www.spaceref.com/iss/element.drawings.html

Yeah your exactly right dave , I knew they couldn't be a circular polarized or helical quad as both require a ground plane and the element itself I believe is called a traveling wave tube amplifier which can have many possible uses one being communications (mostly UHF) the other more widely used is radar

Uses
TWTAs are commonly used as amplifiers in satellite transponders, where the input signal is very weak and the output needs to be high power.

A TWTA whose output drives an antenna is a type of transmitter. TWTA transmitters are used extensively in radar, particularly in airborne fire-control radar systems, and in electronic warfare and self-protection systems. In these types of applications, a control grid is typically introduced between the TWT's electron gun and slow-wave structure to allow pulsed operation. The circuit that drives the control grid is usually referred to as a grid modulator.

Another major use of TWTAs is for the electromagnetic compatibility (EMC) testing industry for immunity testing of electronic devices.

Having grown up with an electronics engineer for a father and spending a large portion of my saturdays throughout my childhood messing around in the field I do recognize some things .

 

[adrenalynn]

>> couldn't be a circular polarized or helical quad as both require a ground plane

No.

>> Having grown up with an electronics engineer for a father

Giggle. "Having slept in a Holiday Inn Express last night"

 

[adrenalynn]

This one caught my interest, so I did a bit of research. As best I can tell, that's the UHF antenna installed on the Destiny module during STS-100. The antenna is used for communication during spacewalks and for station-shuttle communications.

http://www.shuttlepresskit.com/STS-100/eva14.htm
http://www.spaceref.com/iss/element.drawings.html

Great find, thanks, Dave!