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Satellite Back From The Dead
Papa Legba writes "Just ran across this amazing story about an amateur satellite that has returned from the dead. AMSAT-OSCAR 7 was launched in 1974 for radio hobbyists to use. In 1981 the onboard batteries died and the satellite went silent. Then on June 21st 2002, 20 years later, a hobbyist testing some new equipment made an amazing discovery. AMSAT-OSCAR 7 is live once more, both broadcasting and accepting signals. The theory expounded is that the dead battery short that took the satellite offline has cleared and it is now only running on its solar cells. While this does restrict it to daytime use, it is amazing that it works at all. " This was in the science section before - but worth the front page.
to see if it came back attached to a planet-sized ship like in STTMP?
That's my purse! I don't know you! -- Bobby Hill
both broadcasting and accepting signals.
We don't want the first extraterrestrial slashdotting.
Never confuse volume with power.
Just don't talk to this thing for too long. It might not be quite the same as it was before.
Real Daleks don't climb stairs - they level the building.
They don't know we are using their own satellite to relay strategic information to our rogue agents.
Invasion date set to July 1st.
P.S. Make sure mothership is upgraded with latest security patch, we don't want some nerd with an apple laptop to hack our shield system again.
Je t'aime Stéphanie
And all this time I thought those herbal treatments they advertised were stupid scams!
Did the guy who contacted it chance upon the satelitte coming online or was he sending messages to it for 20 years and only now realized that it was offline?
"The large print giveth, and the small print taketh away" -Tom Waits
we just slashdotted them TWICE in 2 days. jesus christ. have some fucking compassion
sig - .
http://www.amsat.org/amsat/news/ans.html
AMSAT Miracle
STOP PRESS - Announcement....
First heard by Pat Gowan G3IOR, Oscar 7 seems to have made a comeback! Pat copied and downloaded CW telemetry. This information was confirmed by several AMSAT members as coming from OSCAR-7. This satellite was launched on November 15 1974, giving it a life of 27 and one half years. The receive frequency was 145.9738.
Jan King W3GEY commented, "G3IOR's telemetry frame is interesting. Apparently he did hear the AO-7 mode B beacon tonight.
"I got out my December 1974 and looked up the telemetry equations for the Morse Code Telemetry Encoder and what I found is in the attached spreadsheet.
"I'm blown away. Most of this stuff makes pretty good sense. In particular, the temperatures make sense and I would have guessed that they would be the most solid IF the reference voltage held (which it did). Interpreting some of this for those who may not understand or don't remember, the telemetry says the spacecraft was in Mode B; all the other beacons and Mode A were off. It is possible that the thing had just turned on because the old 24 hour timer just reset it to Mode B. The damn thing may think it is still on an every other day cycle. The power output of the transponder is 1.16 watts which may mean it is transmitting white noise plus beacon power. That seems about right, but a little low as I recall. The instrumentation switching regulator is in the middle of its normal range and seems to be working fine. The internal temperatures are around 15 deg. C; the external temperatures are around 5 C and the transponder PA temp, which should be the warmest - IS - it's 35.1 deg. C. The array current value is bust. I think maybe it always was. Need to look for some old telemetry to confirm that. The array current calibrations looks off. The array currents are in the normal range but all four show current. This can't be. Only two at a time should show current. Without a battery on line, this is entirely possible. The big find is that the battery voltage telemetry shows a voltage of 13.9 volts. Normal is 13.6 to 15.1 volts. So that would suggest the battery was normal BUT, the 1/2 battery voltage is measuring only 5.8 volts. That can't be. This imbalance probably means that the 5.8 volts is the correct value for the lower half of the battery (which is a low value for that half, if the cells were normal - they are probably not) and there is a break somewhere in the upper 1/2 of the battery string. My guess is the indicated voltage is really what the BCR is putting out with only the spacecraft load as a real load and the battery string has an effective break (or a pretty high resistance) somewhere in the upper half.
"So, this old war horse of a spacecraft seems to have come back from the dead if only for a few moments. And it is telling us, that even in a 1460 km high orbit a cheap spacecraft built by a bunch of hams, without very many high rel parts and without designing for a radiation dose like this, can last for 27+ years in space as far as a majority of its electronics is concerned. Even the damn precision reference voltage regulator is still in calibration!"
Like many of us, stunned by the announcement of the return of an old friend, Past President and BOD Chairman Bill Tynan added "Wow! Shades of Harry Potter and Steven King. It makes one believe in ghosts."
[ANS thanks President Robin Haighton for this item]
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
LOL. I guess the SETI project may actually turn up something after all.
Nasa Catalog Number: 7530
Launched: November 15, 1974
Launch vehicle: Delta 2310
Launched piggyback with: ITOS-G (NOAA 4) and the Spanish INTASAT
Launch location: Vandenberg Air Force Base, Lompoc, California
Weight: 28.6 kg
Orbit: 1444 x 1459 km
Inclination: Inclination 101.7 degrees
Period:
Size: Octahedral shaped 360 mm high and 424 mm in diameter
Modes: A, B, and C
Beacons:
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Linear Transponders:29.502 MHz (200 mw) Used in conjunction with Mode A
145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]
435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)
2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.
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Firsts:Transponder I: Mode A
Type: linear, non-inverting
Uplink: 145.850 - 145.950 MHz
Downlink: 29.400 - 29.500 MHz
Translation Equation:
Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler
Output Power: 1.3 watts PEP (start of life)
Transponder II: Mode B and Mode C (low power)
Type: linear, inverting
Uplink: 432.125 - 432.175 MHz *See Note
Downlink: 145.975 - 145.925 MHz
Translation Equation:
Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler
Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C
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Satellite-to-satellite relay communication via AO-6.
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Early demonstrations of low-budget medical data relay and Doppler location
of ground transmitters for search-and-rescue operations were done using
this satellite.
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The Mode-B transponder was the first using "HELAPS" (High Efficient
Linear Amplification by Parametric Synthesis) technology was developed by Dr.
Karl Meinzer as part of his Ph.D.
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First to fly a Battery Charge Regulator (BCR).
Status: Semi-OperationalTelemetry:
- AMSAT-OSCAR
7 Telemetry web page
- Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for
interpreting telemetry from AO-7 has been made available in the AMSAT-NA
software collection:
- http://www.amsat.org/amsat/ftp/software/spreadshe
e t/AO7tlmSS.zip
- ftp://ftp.amsat.org/amsat/software/spreadsheet
- Please forward AO-7 Telemetry to Jim
White, WD0E.
Description AMSAT-OSCAR 7 was launched November 15, 1974 by a Delta 2310 launcher from Vandenberg Air Force Base, Lompoc, California. AO-7 was launched piggyback with ITOS-G (NOAA 4) and the Spanish INTASAT. The second phase 2 satellite (Phase II-B). Weight 28.6 kg. Orbit 1444 x 1459 km. Inclination 101.7 degrees. Octahedrally shaped 360 mm high and 424 mm in diameter. Circularly polarized canted turnstile VHF/UHF antenna system and HF dipole.Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.
Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.
AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:
Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:
The full text of W3GEY's comments are here.
Initial reports on the health of AO-7 are:
References
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Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb
1974, p. 56-60.
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"OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
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David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
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"OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p.
63.
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Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR
6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE
Letters, Oct 1975, pp 1526-1527.
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D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue
Distress Alerting and Location Using Satellites," IEEE WESCON, Sep
1976.
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J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
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D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp
67-73.
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Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham
Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
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"Technical Correspondence: A Look at OSCAR-7 Telemetry", QST,
Jul 1980, p. 38.
The latest information is available from:Return to Satellite Summary
Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.
Last update June 23, 2002 - N7HPR
I disable sigs...do you?
Daytime use where? Last I checked, it's usually daytime at some point on this planet. But I'd imagine that somewhere we can find out when this satellite is in 'daytime' or not.
Things you think are in the Constitution, but are not.
It seems to me that such a kind of feat was also achieved with the SPOT satellites, except that it was of much more commercial importance.
:)
The SPOT 3 satellite died in orbit on November 1996, way before its SPOT 4 successor was launched (March 1998). Meanwhile, to be able to continue their business, the owners of the SPOT network more or less resurrected SPOT 1, which was launched on February 1986.
Sadly, I don't remember or even knew all the details, so I would be glad if someone could step up to provide some more.
Related, but slightly OT: last November, a 50 Mbps laser link between SPOT 4 orbiting at 832 km and another satellite (Artemis) orbiting at 31,000 km was successfully tested. This allows ground stations to keep contact with SPOT 4 for a much longer time, and avoids having to rely too much on the onboard storage systems. Now, that's high-tech.
V-GER :)
In case of fire, do not use elevator. Use water!
So, basically what they are telling us is that it is illegal to do something that was legal when it originally came out, (which is what the government usually does). We can't use the satellite for it's original purpose.
In other words, it's illegal to talk to previously dead satellites.
Here are the NASA 2-line Keplerian elements for AO-7:
AO-07
1 07530U 74089B 02167.52996888 -.00000029 00000-0 10000-3 0 935
2 07530 101.7955 212.2077 0012102 193.4285 166.6467 12.53558681262239
Also, you may see it's orbit here
I thought I heard a yummy sound. And look at that, you've hardly touched you food!
--
"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
..if that were the case, turning it off and on every day like that might actually make it work [i]better[/i].
Do daemons dream of electric sleep()?
...I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz....
You came across a beacon transmitting S CLUB 7 ?!?!
NO! SHUT THEM ALL DOWN! HURRY! Listen to them, R2... they're dying in there... We're all doomed....
"Lawyers are for sucks."
- Doug McKenzie
So, a 25+ year old satellite wakes from the dead, drifting out in the cold darkness of space.
I find it amazing that a hunk of metal orbiting our planet for longer than I have been alive still functions, yet a modern webserver with possibly more advanced components succombs to slashdotting in minutes.
Solution: Build webservers out of 1974 satellite components. (Although that large gap of 20 years downtime may pose a problem.)
The satellite is NOT in geosynchronous orbit.
NO amateur satellites are there - The cost of launch is simply too prohibitive, and it raises groundstation equipment requirements too much.
The highest-flying amateur satellites (AO-10 and AO-40) are in highly elliptical orbits. Almost all others are in various low-earth orbits, circling the Earth every 80-100 minutes.
Do a freshmeat search for "predict" - It's an excellent satellite position prediction package for Linux.
retrorocket.o not found, launch anyway?
It has a single low-duty-cycle beacon in the 2.3 GHz band. No reception capability anywhere close to the 802.11 bands. Most of the uplinks/downlinks are in the 2 meter and 70 cm amateur bands.
802.11 is just not suited well for space-based communications anyway...
retrorocket.o not found, launch anyway?
As to use of 432.1 - It's iffy.
:)
Illegal or not, most amateurs will not transmit there as it's reserved for weak-signal work, and who knows, they might want to run moonbounce themselves sometime in the future.
If 432.1 were in repeater or FM simplex territory, no one would care.
Either way - The satellite has two uplinks and this only affects one of them.
retrorocket.o not found, launch anyway?
It probably went something like this:
Radio technician: Sir! We're getting a signal from a satellite that's...
Commander: That's what, soldier?
Radio technician: *gulp* Well, sir, there's those stories about ghost satellites... I mean, we always thought they were just, you know, made up...
Commander: What the hell are you talking about, son? Spit it out!
Radio technician: I better just play the transmission for you, sir.
Satellite: BRRAIIINNNSSSS....
Radio technician: It's... it's a zombie satellite, sir. Undead.
Commander: (quietly) God help us all. (to technician) Get me the Pentagon!
Radio technician: Uh... sir... the phone lines are dead! (suddenly the power goes out)
Commander: Oh. My. God. (satellite bursts out of a closet and eats the commander)
"Destroy science and religion. Science would re-emerge exactly the same; but not religion." - Penn Jillette, paraphrased
If memory serves, isn't there a satellite that is, although dead, still orbiting Mars? Wouldn't it be funny if it decided to start chattering all of the sudden to get the SETI folks all hot 'n bothered? :)
To illustrate the difference in equipment requirements depending on orbit:
:)
:)
AO-10 and AO-40 require relatively high-gain antennas (Yagis or dishes) and tracking systems to use them.
Some of the LEO satallites, especially the FM repeater satellite UO-14 (AO-27 is the same type/orbit but runs lower downlink power and isn't on 24/7) are acessible using a $200-300 dual-band handheld with a good whip antenna. Spend $60-70 for an Arrow antenna and you can get EXCELLENT results.
2000+ mile range with 5 watts and an entirely handheld setup - Talk about cool.
From Ithaca, NY, I have heard a station in Mexico and one in Edmonton, AB on a regular basis via UO-14. I've even heard California.
Andy, N2YPH
I need to replace my antenna... The old one sucked and broke. Only $10 though.
retrorocket.o not found, launch anyway?
Eloi are stupid, throw morlocks at them!
This is an Amateur Radio satellite, so you need an Amateur Radio license to work it.
See www.arrl.org/hamradio.html
for a general overview of Ham radio.
Then you can set up your radios and antennas.
A page was referenced, but posted by an AC so its only at 0. Here's the link again: www.qsl.net/vk3jed/1st_sat.html
As for books, look around the ARRL site, they have a vast collection of good books.
-----------
73 de K6LNX
-----------
LinuxKnight
here (6/25/2002)
Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
yeah, this sure belongs here, when the openssh vulnerability was left in a slashback. go /.! and uh, upgrade your openssh kiddies.
Captain: What happen ? ....
Mechanic: Somebody set up us the bomb.
Operator: We get signal.
Captain: What !
Operator: Main screen turn on.
Captain: It's You !!
Satellite: How are you gentlemen !!
Satellite: All your base are belong to us.
Satellite: You are on the way to destruction.
Captain: What you say !!
Satellite: You have no chance to survive make your time.
Satellite: HA HA HA HA
Captain: Take off every 'zig' !!
Captain: You know what you doing.
Captain: Move 'zig'.
Captain: For great justice.
1974... Then on June 21st 2002, 20 years later
Subtraction.
-
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
Does this mean anyone who communicates with the satellite is a necromancer?
Just because you can mod me down, doesn't mean you're right. Shoes for industry!
One of the neatest features of Predict is planettrack, which interfaces with xearth or xplanet to display satellite positions, tracks, and coverage areas on your root window.
:)
It has a really nice socket interface with some good Perl example code, which I was hoping to use to automatically do Doppler correction for a Kenwood TS-790 (I think that was the model... Either way, it was a dual-band all-mode VHF/UHF rig W2CXM bought for satellite work - But I graduated so no more TS-790...)
It has built-in support for a few automatic antenna tracking systems, and for the rest there's the socket interface.
retrorocket.o not found, launch anyway?
...after 20 years, a lifeless entity coasting through the cold vacuum of space suddenly sputters to life.
There's hope for my marriage, after all.
This is my post. There are many others like it. If you don't like what you read here, go try one of the others.
Well, for one, there is the "Cool factor" of satellite.
Secondly, HF propagation is susceptible to the whims of the Sun.
Thirdly, you can achieve higher bandwidths at satellite frequencies.
Lastly, and now that I think about, most importantly, is one of the reasons I pointed out earlier - At VHF/UHF, antennas are much smaller - You can get incredible range out of a tiny package, whereas with HF you need comparatively huge antennas.
retrorocket.o not found, launch anyway?