26 votes
Accepted

What is carrier lock and bit lock?

First you lock on to energy at (or near) the expected frequency. That’s carrier lock. Then you start to look for patterns in how the phase changes. The transmitter is coding groups of bits as phase-...
Bob Jacobsen's user avatar
  • 12.7k
21 votes

Will there be live HD television from Mars with the Mars 2020 mission?

Hobbes' answer explains why live broadcast is currently not feasible from the Mars side. I'd like to complement it with why this is currently not feasible from the Earth side. Mars power budgets are ...
Bear's user avatar
  • 1,565
12 votes

Will there be live HD television from Mars with the Mars 2020 mission?

The JPL Mars Helicopter Scout transmitter can send data at up to 250 kb/s, an order of magnitude short for HD video. Communications with the rover are through a radio link called Zig-Bee, a ...
Hobbes's user avatar
  • 128k
11 votes

How were Intelsat 1 “Early Bird” and Telstar 1's "hundreds" of simultaneous telephone conversations multiplexed/demultiplexed?

It was done on the ground, and frequency-multiplexed. In this arrangement, 12 individual telephone channels are frequency-multiplexed into the 60 to 108 kc band as shown. Source: Results of the ...
Organic Marble's user avatar
8 votes

How were Intelsat 1 “Early Bird” and Telstar 1's "hundreds" of simultaneous telephone conversations multiplexed/demultiplexed?

Was it [the multiplexing] all done on the ground and the satellites were "bent pipes"? Even nowadays, almost all GEO satellites are "bent pipe", meaning that they re-transmit the ...
Ng Ph's user avatar
  • 2,724
4 votes
Accepted

Are these good specifications for a X-Band High Gain Antenna?

Doing a scaling process from the performance of the telecommunications ("telecom") system of NASA's Cassini spacecraft at Saturn, I estimate the system you describe could support a data rate ...
Tom Spilker's user avatar
  • 18.3k
4 votes

Can the Tirada-2S satellite communications electronic jamming system be used to jam the Starlink network?

Per @ErinAnne's comment: the answer is almost certainly yes. Generating broadband electronic noise sufficient to reduce the signal-to-noise ratio of consumer-grade equipment like Starlink is trivial; ...
DialFrost's user avatar
  • 1,673
4 votes

Turbo code used in New Horizons - encoding coefficient?

Reproducing CCSDS 101.0-B-4 Table 4-2: Information block length k Codeblock length n for rate 1/2 for rate 1/3 for rate 1/4 for rate 1/6 1784 3576 5364 7152 10728 3568 7144 10714 14288 21432 7136 ...
Erin Anne's user avatar
  • 11.2k
4 votes

Will there be live HD television from Mars with the Mars 2020 mission?

According to this specs page, Mars 2020 Rover will have three kinds of antenna: Ultra-High Frequency Antenna, X-band High-Gain Antenna, X-band Low-Gain Antenna. The one used to send data to Earth are ...
BlueCoder's user avatar
  • 2,113
3 votes
Accepted

How are satellite operating modes implemented?

No experience of satellites here, but I used to do real-time software development. I believe that the point is to discover "normal" from "abnormal". You would have several different "functions" that ...
ghellquist's user avatar
3 votes

Can the Tirada-2S satellite communications electronic jamming system be used to jam the Starlink network?

This is very questionable at least. Earth curvature. Tirada-2 is a ground based satellite jamming system. The frequencies the satellites use are in the range of several tens of GHz. The waves so ...
Nightrider's user avatar
  • 2,035
2 votes

How were Intelsat 1 “Early Bird” and Telstar 1's "hundreds" of simultaneous telephone conversations multiplexed/demultiplexed?

The telephone channels routed over the satellites were frequency multiplexed. Frequency multiplexing of telephone channels was an established technology used for the transatlantic cables TAT-1 and TAT-...
Uwe's user avatar
  • 49k
2 votes

Curiosity / MRO UHF connection and weak signal modulation

Another interesting paper is The Electra Proximity Link Payload for Mars Relay Telecommunications and Navigation (C.D. Edwards, et al., 2003), which is reference #21 in the DESCANSO paper @...
Ryan C's user avatar
  • 7,942
2 votes

Curiosity / MRO UHF connection and weak signal modulation

The MSL DESCANSO article states that it is MRO that monitors the SNR and controls the data rate (section 2.2.2): In this mode of operations, it is the MRO radio that controls the return data rate, ...
BrendanLuke15's user avatar
2 votes

Has FCC jurisdiction for all the world for SpaceX's Starlink position?

Space politics is complicated - at a bare minimum you need approval from the regulatory body that has jurisdiction over the region that you plan to transmit/receive over. Depending on the launch ...
mothman's user avatar
  • 968

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