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Intelsat To Start Refueling Satellites In Orbit
mangu writes "Intelsat has signed a contract with Canadian MDA to refuel satellites in geostationary orbit. The $280 million contract will buy half of the 2000kg fuel carried by the space servicing vehicle. Besides refueling aging satellites, the vehicle will also be able to tow failed satellites away from the geostationary orbit."
AAA members can get 2 gallons of fuel free when the call the tow-truck. At 75$ a year membership fee, just get 1000 memberships and you can ask for 4000 gallons for $75000. And if you put it on the Discover card, you get 1% cash back too.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
We are at about $3.70 per gallon here in Oregon; what is the projected price up there?
Most Respectfully Yours Mark Allyn Bellingham, Washington
I thought most of those things were solar powered. Is this just for propulsion systems (to lift them out of decaying orbit, or move around) or something?
SJW: Someone who has run out of real oppression, and has to fake it.
Intelsat's Galaxy 15 satellite was successfully rebooted in December and is responding to commands and no longer interfering with other satellites. http://en.wikipedia.org/wiki/Galaxy_15
I've lived at the bottom of a hill, i.e. with bad TV reception. The switch from analogue to digital has basically ruined things for me, because it's quite easy to cope with a grainy picture and occasionally slightly hissy sound (but rarely - FM's damn resilient) but impossible to cope with the blockiness and intermittent loss of soung with DVB-T.
How well has the transition to digital satellite gone? When it's pissing down with rain, will I just get little lines on the screen like on my old analogue receiver, or is there a similarly horrible loss of actual watchability?
This story just triggered my geekometer. To me, this step seems so cool, that we now have space gas attendants and junk men. It makes me feel as if some of the science fiction that I've read is not so far away after all.
But then I realized the cable was blue, so I only gave it one star. I hate blue.
With refuelling, it is much, much cheaper to operate a satellite for a longer time. You get extended lifespan for a fraction of the cost that would be needed to build and launch another satellite as replacement. Sure, the initial cost of developing and lauching the service vehicle is high, but divide it by the number of satellites it can service and you get a really small amount. Also, it solves the problem of 'zombie' satellites, as recently exemplified by Galaxy 15.
Nothing I read specifically says this, but I'm assuming that the MDA SIS is an unmanned vehicle?
If so, that's pretty interesting.
Proverbs 21:19
Symbol rate is the speed at which the bytes are transferred. It's usually in Baud, so if you have ever played with a classical modem (14K4 for example, it means 14400 Baud) you should know something about it.
Channels are multiplexed into a transponder. For example the Astra 1 at 19.2 E satellite (default here in NL) has a transponder 97 (12344 MHz, horizontal) with 25 channels on it (13 TV and 12 radio channels). These channels all have a different addresses (I believe they are called PID's). Video signals have even 2 (one for audio and one for video). There is some system that tells the receiver what addresses are taken at the moment and some system that creates a start (an adress 0). From the start point each channel is send when it's time slot is there. The receiver simply waits until the correct time slot and puts the data into the input buffer.
Most satellites nowadays use Mpeg 2 encoding to compress the data. Due to this there is a lot of spare space on the satellite, although Astra 1 contains about 700 channels (radio + TV).
What most people (including me) refer to as a satellite is usually a bunch of satellites. They are positioned in a geostationary orbit within an angle of 0.1 degree. The receiving disk people use is to small to distinguish between them, so it appears as one sat. The opening angle of a 60 cm dish is about 2 degrees. This determines the effective resolution. I believe communication satellites (sattelite groups) are never spaced less than 3 degrees apart, so it's quite easy to distinguish the sat. With a bigger disk (80 cm, 1 meter) you have a smaller opening angle, so you receive less noise and thus effectively a stronger signal. A bigger disk also has a larger area, and thus the absolute signal strength is higher as well. Off course you should not increase to a disk with an opening angle of less than 0.1 degree, or you won't be able to receive the complete group.
The Astra 1 satellite (or group of satellite's if you will) sends at 10 to 12 GHz, with two polarisations (Horizotal and vertical antenna's give different signals). The frequency is way to high to send over a cheap cable, so it's downconverted. This is done by the LNBC, the small box on the receiving disk. This thing does a couple of tasks:
This LNBC is quite an interesting thing. It's a high frequency device (up to 12 GHz) but it is cheap (you can have one for less than EUR 20). Most of the parts are etched into the PCB.
The signal is send over a relatively cheap (like 1 euro per meter) to the set-top box. There is a great variety in these: simple ones, versions with recording harddisks, versions that can display two different channels (PIP or different outputs), versions for HD signals. Even versions with Linux as main operating system (the Dreambox).
In the receiver is usually a smartcard with encryption data. This can be directly into the receiver, but sometimes there is a PCMCIA-like "sleeve" (a module) in the receiver with the card in that. The receiver (or the module) decrypts the signal with the data from the smartcard. Both ways usually work
There is a strange thing with brands: While Phillips and Nokia make satellite set-top boxes (sometimes called receivers) the best brands (IMHO) are not very well known in other fields (Topfield is a good brand. I have not heard of a non-"digital set-top box" product from them. They do have quite good cable receivers.). I am not sure why this is. Phillips receivers in the Netherlands are very locked-in devices and a Nokia receiver is something you
Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
to my dream of being a space handyman. Free optic washing with every tankful. The life of a space cowboy for me. The littlest hohouse on Venus and all that malarky.
According to this animation http://www.mdacorporation.com/corporate/news/press/ServiceMission.cfm they can send additional fuel to the satellite servicer when it's empty.
Did this make anyone else think about the 'automated repair station' from that episode of Enterprise?
http://www.mdacorporation.com/corporate/news/press/ServiceMission.cfm
I always thought satellites used circular polarizations (clockwise and anticlockwise) rather than horizontal/vertical because having the signal reflect off a surface has a very nasty tendency to twist the signal about. And circular polarizations make the orientation of the LNB less of an issue...
The LNB does two things - besides downconverting the signal, it also amplifies it since the receiver box can be far away. Incidentally, the LNB is an active device, but it gets its power (and polarization switching) from a DC signal produced by the receiver - switch polarities and the LNB switches polarizations.
Hello my northerly neighbors! I have a question for you all. I've been doing some research into the Canadian space industry and so far what I have found has impressed me. It seems that the space industry in Canada, while small, is quite ambitious and capable. You all have a well developed microsat industry. You have a good track record for space robotics (just look at all the stuff you added to the ISS). Hell, you even have a Canadian astronaut program, not many countries can claim that.
So, I've got a question for the locals up there. How much does your country seem to value the development of the space industry. Down here in the States, it seems like there is a very enthusiastic minority of folks here who value the space industry, but the majority of people just can't be bothered to give a damn. How much does Canada value its own space industry?
Motorcycles, Robots, Space Gossip and More!
Both types of polarization are used, depending on the satellite owner's preference. Intelsat is almost strictly circular on their transcontinental links, while the majority (if not all) domestic US birds are linear polarization.
Not all LNBs can do active polarity switching. LNBs for fixed VSAT terminals and fixed recieivers have their polarity adjusted by manually turning the feedhorn.
No, there is no ATSC over satellite. You have either analogue Baseband audio/video which can be either clear or encrypted with Videocipher.
For digital, almost everything over the US is DVB-S or S2, with the occasional Digicipher outlier. DVB is often encrypted using Irdeto or similar conditional access.
Yea, it is geeky. Plus, you can watch lots of TV channels you may not normally get, from countries you didn't know about, or in languages you didn't know existed. Search for Free to Air satellite TV. Below is a good starting point: http://www.ftalist.com/index.php
The new bolted on satellite then carries out station keeping maneuvers until it's own tanks are depleted, or until the satellite owners give up on it (in which case they typically use a little fuel to send it to a higher graveyard orbit).
Symbol rate is the speed at which the bytes are transferred. It's usually in Baud, so if you have ever played with a classical modem (14K4 for example, it means 14400 Baud) you should know something about it.
DVB Satellite signals are specified in Megasymbols/sec, not baud. A DVB carrier is specified by the a few parameters:
Center frequency (either in the actual downlink frequency from the satellite or in L-Band after the LNB)
Symbol rate (In kilo or megasymbols/sec)
Modulation (BPSK, QPSK, 16PSK, 32PSK)
FEC rate (1/2, 3/4, 7/8)
Once you lock onto the stream, then you can dig out the various PIDs.
Channels are multiplexed into a transponder.
Not multiplexed onto a transponder, but multiplexed into a carrier. A transponder can have multiple carriers, each carrier can have mutliple channels (separated by PIDs). Transponders are just a chunk of raw spectum on the satellite, each usually either 36 or 72MHz wide.
Most satellites nowadays use Mpeg 2 encoding to compress the data.
Technically, it's not the "satellite" that encodes the signal. The satellite is just a "radio bent pipe" in space. The ground station is what encodes the signal, the satellite just retransmits what it gets. MPEG-2 is the prevalent digital compression mode, but more services are going to MPEG-4, especially for HD video and on DVB-S2.
Not trying to be pedantic, just making sure the right terms are used. Having been in the satellite industry for 10+ years now, those things annoy me just as much as someone saying "I've got 250GB of memory in my computer"
I want some of those stocks.
Most people don't know or care much about the space industry, and the geeky types think it's cool. Due to a good TV miniseries I suspect most people know about the Avro Arrow than about the current contributions to space exploration and industry.
Okay, instead of using the word kilometre let's all refer to thousands of metres. By the way: 2000kg == 2 tonnes. *sigh*
how is babby formed?
"Classical modem" Oh crap, I'm getting old! (Or Classical as it were!) :-)
I am using over the air digital signal with a D->A converter box, I found that a cheap (about $30) Walmart TV amplifier made a big difference in signal. Save the receipt, be gentle opening the package (I used a razor) and if it does not work in your particular case then just return it...
You have the right to remain sentient. If you give up the right to remain sentient, you will be elected to public office
From wikipedia:
How did you get 26? 26 isn't even divisible by 3...
There were 11 manned missions that lifted-off and 2 of of those didn't go further than low earth orbit.
9*3 = 27.
DVB Satellite signals are specified in Megasymbols/sec, not baud.
The definition is technically right, but wrong for the common lingo. Baud means "symbols per second." Hertz means "per second." You'd never hear anyone in the satellite industry say anything other than megasymbols per second (usually Msps from what I see, but some people have a hard-on for using Ms/s or such to avoid having the "/" be represented by a letter). Hertz isn't limited to frequency, but could be indicating symbols as well, but you'd never see anyone say "megasymbol hertz" or such, though technically correct.
Having been in the satellite industry for 10+ years now, those things annoy me just as much as someone saying "I've got 250GB of memory in my computer"
I was going to go through the rest of the post and pick out other parts where he wasn't wrong, but just using inaccurate lingo. But this one works well enough for anyone that doesn't know satellite. 250 GB of hard drive memory. You are assuming RAM is the only thing that's "memory." It's not. That may be how you hear it. And you may be a "expert" at satellite. But that doesn't mean the only way you are used to hearing it is the only technically correct manner. A hard drive is memory. It just isn't RAM (though technically it is a form of random access memory as well). Just because someone doesn't have the lingo down doesn't mean they don't understand it.
Learn to love Alaska
Can you break down that math? It sounds like you left out either Apollo 8 or Apollo 10, both of which included 3 astronauts that went beyond LEO.
Come on, it's only 8 dollars / US gallon here in the Midlands. Mind you stuff always costs more in London ....