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37 votes
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What exactly turned on the light indicating Apollo 8 was starting to fall towards the Moon?

The Apollo Guidance Computer used a state vector either centered at the Earth or the Moon. The switchover point is the the lunar sphere of influence, defined in the AGC as 64,373,760 meters (https://...
indy91's user avatar
  • 1,991
36 votes
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Does SpaceX use any of Falcon-9's camera data for engineering or status information, or are they "just for PR"?

A caveat about this answer: it's not about SpaceX directly, more about the use of self-inspection cameras in general across space and launch vehicles. It is used for engineering and status ...
Tristan's user avatar
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24 votes
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Was the Soviet N1 really capable of sending 9.6 GB/s of telemetry?

That claim is rather dubious. First, there is the claim of 320,000 channels of telemetry, while one paragraph earlier it lists 13,000 sensors on board. There will be setpoints in addition to sensor ...
Hobbes's user avatar
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22 votes

Why won't NASA show any computer screens?

A long, long time ago, I managed to arrange to get two passes to see the first light from one of the Voyager flybys of Jupiter. I collected on lots of debts and pulled lots of strings to get those ...
David Hammen's user avatar
15 votes

Does SpaceX use any of Falcon-9's camera data for engineering or status information, or are they "just for PR"?

There is value added. I was an operator of a satellite that had a video of the satellite being deployed. We were able to see from the video that the deployment was clean. I assume if nothing goes ...
PearsonArtPhoto's user avatar
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10 votes

How do we know Starship 28 was lost?

This question is simply counterfactual. The call was not immediate by any stretch of the term. On the stream from SpaceX, the video from Starship breaks up about T+48:40, and over the next 90 seconds ...
Darth Pseudonym's user avatar
9 votes

Why won't NASA show any computer screens?

In trying to explain my feelings on this question in comments on the other answer, I came around to a possible explanation -- There could be a real PR cost to publishing raw data streams in real time. ...
Saiboogu's user avatar
  • 6,417
8 votes

What does a NASA employee see on their monitor when a robot lands on Mars?

Those people in the control room just see various things on their screens (see the attached image). It is quite evident that not all the monitors show the same data. NASA JPL Mission Control Room, ...
makelele's user avatar
8 votes
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Why did Sputnik-1 transmit on both 20 and 40 MHz?

Russian version of Sputnik-1 Wikipedia article has the section labeled "Sounds of Sputnik" and cites the respective technical report regarding development of the Sputnik's "radio device&...
Sergiy Lenzion's user avatar
7 votes

How do we know Starship 28 was lost?

They lost communications with two independent systems simultaneously, if this was due to interference you'd expect them to be lost at slightly different times as they use different transmitters, ...
Alan Birtles's user avatar
  • 2,066
6 votes

Was the Soviet N1 really capable of sending 9.6 GB/s of telemetry?

I suspect this confuses "bandwidth available" with "bandwidth that can be used concurrently at any one time". It certainly could not be processed at that rate by the ground based systems, let alone ...
ANone's user avatar
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5 votes
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How will Icarus aboard the ISS track bird migration?

It seems they have very small miniaturized tags on animals that do include GPS along with other sensors and they can transmit up to 800km. See the technical pdf at the end of this page Direct link ...
BlueCoder's user avatar
  • 2,113
5 votes

Is there an archive/database of ISS telemetry over time?

Within the NASA firewall: yes, there is a service available to bring up recorded telemetry. I've not used it personally, but I know it's available. Publicly: The only archives I know of are where ...
Tristan's user avatar
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5 votes
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How can I know if NASA Horizons output is measured, calculated, estimated or what-else?

No, these are from measured orbit determinations. However the data does go into the future somewhat, as you can see from the table below. The "od" you see in the rows means "orbit determination", and ...
Mark Adler's user avatar
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5 votes
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SpaceX second stage altitude decrease?

This is actually pretty common in rocket launch profile design. For the Ariane rocket, we covered it in What is the reason for the Ariane 5 launcher with Intelsat 29e losing altitude?, but the same ...
PearsonArtPhoto's user avatar
  • 121k
5 votes
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Besides the (currently down) HDEV, are there other public live video feeds from the ISS?

Ok, it appears they are now using the EHDC, a different camera that doesn't always have availability, to provide a live video feed. It would be great to get access to additional feeds though. https://...
CourageousPotato's user avatar
5 votes

What was the first use of analog to digital conversion in a satellite?

The very first analog to digital conversion was used in the first satellite ever: Sputnik 1. A barometric switch was used to signal if the gas pressure inside dropped below 130 kPa. A mechanical ...
Uwe's user avatar
  • 49k
5 votes
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What did Sputnik-1 sound like? Did it use multiple tones?

It appears to just be a carrier signal alternately transmitted and not transmitted. As the carrier is in the MHz range, the audio cannot be a direct mapping of that frequency. I don't know the ...
BowlOfRed's user avatar
  • 6,882
5 votes

How did Argentina, Namibia, and Pakistan help China monitor and communicate with Chang'e 5?

There is a Chinese run ground station in Swakopmund, Namibia. Image source This station is part of the "Chinese Tracking, Telemetry, Command and Communications System", which has similar ...
samcarter_is_at_texnique.fr's user avatar
5 votes

How did Argentina, Namibia, and Pakistan help China monitor and communicate with Chang'e 5?

In 2014 China and Argentina signed an agreement that allowed China to establish and operate a deep space station in Argentina. According to Reuters, the Chinese military runs the station in Argentina. ...
Fred's user avatar
  • 13.1k
5 votes

What is wrong with Voyager 1 attitude data telemetry? Is there a test version of the computer available?

The AACS was writing data to a wrong memory address: The AACS had started sending the telemetry data through an onboard computer known to have stopped working years ago, and the computer corrupted ...
Ludo's user avatar
  • 14.4k
4 votes
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Will Red Dragon experience a "Communications Blackout" during SRP?

Not much is known about Red Dragon yet. There will be a brief communications blackout. For Mars the blackout period is around 30 seconds. Detailed study of comms blackout for Mars. Blackout is ...
Hobbes's user avatar
  • 128k
4 votes

Distinction between spacecraft data and telemetry - difference in spacecraft resource use?

I agree with Hobbes about TM being a subset of data, but from my experience I would define it differently: Spacecraft data: just all data that is inside the spacecraft at some time, no matter whether ...
Stefan Bormann's user avatar
4 votes

Voyager's distance from Earth

About 29 au away. Speed * time = distance (since speed has units of distance/time). For this problem, the units are as follows: $$C \text{ meters}/\text{second} * 4 \text{ hours} * (60*60) \text{ ...
Andrew W.'s user avatar
  • 976
4 votes

Was the Soviet N1 really capable of sending 9.6 GB/s of telemetry?

I don't have any original sources, but I'd say: 9.6 GB/s are possible, albeit not an accurate description. It's very likely that the largest amount of data was not transported digitally but as raw ...
asdfex's user avatar
  • 15.1k
4 votes
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What was the first use of analog to digital conversion in a satellite?

The first analog to digital converter was flown on board Injun 1 on June 29, 1961. It was also the first spacecraft completely designed and built by a university--in this case, the University of Iowa. ...
called2voyage's user avatar
  • 23.7k
4 votes

What did Sputnik-1 sound like? Did it use multiple tones?

The short answer to this question is that. No, it did not transmit audio beeps to radios. Sputnik 1 had a transmitter that would alternately turn off and on by a circuit called “the Manipulator”. It ...
Aaron Carrillo's user avatar
4 votes
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Can satellite internet be used for monitoring rocket telemetries during testing phase?

I was involved in a project that tried to gather some data from the reentry phase of spent stages. At this time, Iridium was the only available provider of data links via satellite. It was soon found ...
Ludo's user avatar
  • 14.4k
4 votes
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Telemetry: How do we manage to get a message to a tiny satellite that may be millions of kilometers away?

Firstly, because we know exactly where the target is. The location of a Satellite, or planetary probe, is known down to literally a small number of meters. Yes, even when this probe is moving at ...
CuteKItty_pleaseStopBArking's user avatar
4 votes

What did "verb 50 - noun 90" mean during Apollo 11 powered descent? (1202 alarm)

Apparently the answer is "They don't mean anything, it's a telemetry bug". More precisely, that "Verb = 50, Noun = 90" actually reads "Verb = 5, Noun = 9". i.e., Aldrin ...
jumpjack's user avatar
  • 3,033

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