Space Antennas

Two weeks ago I did visit the exhibition NASA - A Human Adventure at the Technical Museum in Stockholm, Sweden. An exhibition with not only scale models from space exploration history, but also full scale models that cannot be distinguished from the original ones. As a radio amateur I had special interest in some of the antennas being shown :-)

This is the Russian Lunokhod (Moon walker) with is solar panel lid flung open. One antenna half is an ordinary helix UHF antenna, but what is the purpose of the other half? Anyone knows?

The Lunar Rover´s umbrella antenna has a black strange object at its back. What is it?

Update 6 April, 2011

It is possible to download from NASA the Lunar Rover Operations Handbook. On page 119 there is a drawing explaining that the black object is an optical sight.

This is Sputnik 1, the first satellite, weight 83 kg and diameter 58 cm. From Wikpedia I found following information about its antennas.

The satellite carried two antennas designed by the Antenna Laboratory of OKB-1 led by M.V.Krayushkin. Each antenna was made up of two whip-like parts: 2.4 and 2.9 metres (7.9 and 9.5 ft) in length, and had an almost spherical pattern, so that the satellite beeps were transmitted with equal power in all directions; making reception of the transmitted signal independent of the satellite's rotation. The whip-like pairs of antennas resembled four long "whiskers" pointing to one side, at equal 35 degrees angles with the longittudinal axis of the satellite.


Ham Radio said…
Wow...amazing antenna.
Very nice pic also!
F8ARR said…
"The Lunar Rover´s umbrella antenna has a black strange object at its back. What is it?"

Is it not simply a counter point ?
Yes, I think you are right. Mni tnx!
This comment has been removed by the author.
The black object is an optical sight. Pse see update above.
Roland Turner said…
I'd guess that the discs in front of the helix on Lunakhod are analogous to the director elements on a Yagi: they're smaller than resonant diameter so they both reflect shorter wavelengths (i.e. a low-pass filter) and improve forward gain for resonant wavelengths. I have no strong basis for this.