Caption Competition
18 January 2009
You win nothing except my admiration for either determining what these NASA gimps are up to, or providing a suitable caption:
Original URL, for sleuths: http://www.nasa.gov/images/content/169065main_image_feature_757_ys_full.jpg
12 Comments
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*sigh* “Man… wouldn’t it be great if these things actually did anything?”
Mine’s bigger than yours?
Check your mail for response.
ah….that’s what you do with the coil!
“Don’t get cocky kid!”
These DTV converters seemed a lot smaller in the commercials…
Its been four hours. The label says we should seek medical attention
Tesla’s death ray has nothing on these.
No caption ideas, sorry.
Those are helical antennas – usually used for communication with satellites (because the attitude changes of relative orbital position makes circular polarization essential – dipoles would drop in gain as bore sight angle changes between the send and receive antennas – like when you rotate a pair of polarizing lens).
Based on the fancy engineer’s uniform (white shirt and tie) I’d say late 1950s, early 1960s. Further the diameter of the helices is proportional to the radio wavelength being used – clearly these are high VHF, low UHF bands, longer than than 10 cm, maybe 15 cm. That’s 200-300 MHz on the low end. That’s clearly not 1960s – definitely 1950s.
Most likely they’re pulling telemetry from some satellite. These are receive-only. No visible transmitter or waveguide to a transmitter. At those frequencies and in those years, either the transmitter or its waveguide would be big and noticeable.
These facts mean it’s an early satellite program. You gave away that it was NASA’s photo and people rather than military which radically reduces the US possibilities. The fact that they are doing manual Az-El suggests either a very early period or something very experimental.
Without the the date it might have been something as late Mercury, but more likely Explorer/Vanguard. But this assumes it’s one of ours they’re listening to. The date and frequency combined with the equipment design/quality suggest something else:
They are set up to listen to the signals from the first USSR Sputnik satellite.
@Jeff
Stunning reply. That’s a very cool piece of reasoning, with a fascinating conclusion. So that would make it post the late 1957 launches. Do we know how long the various Sputniks remained in orbit? I know Laika never made it back alive but presumably she’s not still up there in her orbital coffin.
Wikipedia has most of the info on sputnik. Thankfully since the Wall came down it’s been vetted for correctness by the folks who know most of the story, Russians involved in the project. For example, I don’t remember us knowing who the Russian designers were yet they’re listed on the page.
http://en.wikipedia.org/wiki/Sputnik
Sputnik 1 through 6 between 1957 and 1960. The wikipedia page for Sputnik 1 says it re-entered after three months (Jan 4, 1958).
However:
I didn’t look at the Sputnik wiki page before posting but I really should have – the radio wavelength is wrong (20 MHz/15 m) for the helicals for it to be Sputnik. I should have remembered thousands of regular people in the US were listening to the Sputnik signal with shortwave radios. Duh! My bad. A helical for that frequency would have been 3m in diameter helix. Clearly not what we see.
Sorry for the bum steer. But digging deeper:
Vanguard beacons were 108 MHz, 2.7 m, low VHF, which is closer to range for the helical dimensions (lambda/3 for diameter or just under a meter) but still the wrong size, and also Vanguard 1-3 were Navy, not NASA. NASA’s Explorer 1-3,7-8 were also 108 MHz. NASA’s Pioneer 1-2 also 108 MHz. Explorer 9 was 136 MHz, 2.2m. Much later than that and I have my doubts.
http://en.wikipedia.org/wiki/Explorer_1
http://en.wikipedia.org/wiki/Explorer_2
http://en.wikipedia.org/wiki/Explorer_3
http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=1959-009A
http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1961-004A
http://en.wikipedia.org/wiki/Pioneer_1
http://en.wikipedia.org/wiki/Pioneer_2
NASA’s Explorer 4 had a 400 MHz/75cm beacon (low UHF) for a helical diameter of 25cm. It was launched in 1958 and orbited for 454 days. Explorer 5 was destroyed on launch and identical to Explorer 4.
http://en.wikipedia.org/wiki/Explorer_4
http://en.wikipedia.org/wiki/Explorer_5
Explorer 6 has both VHF and UHF beacons, launched in 1959. Very different design physically and apparently had power problems so the UHF was used only intermittently.
http://en.wikipedia.org/wiki/Explorer_6
US Army Pioneer 3 was 960 MHz or ~3 cm. That would be a 1 cm helical diameter. Wrong size in the opposite direction. It was a re-entry vehicle test bed for ICBMs and looks it. NASA’s Pioneer 4 was the same hardware as the Pioneer 3 but used for a moon flyby.
http://en.wikipedia.org/wiki/Pioneer_3
http://en.wikipedia.org/wiki/Pioneer_4
NASA’s Pioneer 5 was low enough power it needed/used the big parabolic stations to pick up its telemetry. Probably a TWT Like pioneer 6. The rest of the NASA Pioneer series used TWTs which means there were all in the microwave range at shorter wavelengths than 1 GHz/3 cm.
http://en.wikipedia.org/wiki/Pioneer_5
http://en.wikipedia.org/wiki/Pioneer_6,_7,_8_and_9
Looking at the helical dimensions again, 25 cm looks about right in the picture, leaving only two likely candidates: Explorer 4 is most likely, with a smaller chance of Explorer 6.
@Jeff
You’re clearly a sterling footpad in the world of comms technology, and I appreciate the effort. Explorer 4 or 6, you say?
Explorer 4, launched July 1958, for the purpose of studying Van Allen radiation. Very cool. Wasn’t one of the Sputniks meant to do this too, but failed to reach orbit or something?
Explorer 6, launched August 1959, with a broader range of instruments to study different radiation types. Also transmitted the first images of Earth from orbit. Spectacularly cool.
All this reminds me of childhood obsessions in the 70s. Space, satellites, any kind of orbiting hunk of metal, dreaming of Mars and Star Wars. Drifts off into reverie …
Many thanks for researching this, Jeff. It’s hugely appreciated.