New answers tagged history
1
The library of Congress has a picture of these hearings, although it appears to be under copyright, so only a thumbnail of the picture is available on the LOC website.
1
Side note: The US does not use imperial units. There are subtle differences between imperial and US customary units.
I have seen multiple claims that von Braun despised US customary units. But he pretty much had to live with those US customary units, at least as far as hardware was concerned. The same pressures that made von Braun hate but be stuck with US ...
1
The 1960 translation by Syers, which you link to, is available for short loan (1hr) from the Internet Archive / Open Library.
The ISFDB has a reasonably complete list of editions, which identifies a 1963 translation by Dutt in a volume called Call of the Cosmos. This volume is available to read via the Internet Archive. (I am a little unclear on the ...
3
The PFS- satellites were inserted into a lunar orbit in order to map, amongst other things, its gravitational field. So you would expect their orbit to be accurately known and monitored. The Apollo 16 mission report gives the following orbital parameters in Sect. 5-5
PFS-1 : Perilune 105 km, Apolune 144 km, Inclination -28 deg
PFS-2: Perilune 97 km, Apolune ...
3
On that particular date, a cargo spacecraft called the S.S. Gene Cernan was in orbit after completing a supply mission to the International Space Station. The Cygnus-class spacecraft was built by Orbital ATK; launched from Wallops Island on November 12, 2017; docked with the ISS carrying 3338 kg of cargo; and left the ISS on December 6 with 2900 kg of trash....
4
Every analysis of the Fermi Paradox is an opinion. I think it always bears mentioning that. We posit the existence of civilizations up to billions of years old based on a set of assumptions that seem very sound. Then we predict their behavior, even though we only discovered farming 12,000 years ago. It's a mistake to draw conclusions about species that, if ...
5
If you skip forward to p11, there's a transcript of her description of the images - it looks like there were three pictures, all connected with the isolation tank tests. It's also worth noting that it was Cobb showing the pictures, not Hart.
(Pictures.) So with that we will go ahead with the slides and I will briefly describe these as we go through them.
(...
3
Although this doesn't really look like a Congressional hearing photo, the source claims it is. The legend says "Jerrie Cobb and Janey Hart testifying before congress. (Netflix)"
It may look like this because the testimony was before a Subcommittee and not the full Congress:
Subcommittee of the House Committee on Science and Astronautics,
headed by ...
9
On July 11th 2021 16 people were in space1 at the same time.
Seven people on the International Space Station: Three Americans, two Russians, and one from both France and Japan.
Three Chinese on the Tiangong Space Station.
Six people on Virgin Galactic's Unity, including Richard Branson, two pilots, and three Virgin Galactic employees.
1Unity reached a ...
1
The RS encoder is similar to Golay and Hamming encoders (shift-register based). For example, this resource gives a schematic diagram.
In principle, it is as "simple" as binary encoders (check bits calculated from info bits). The main difference (and complication) is that additions and multiplications now operate on bytes (check bytes calculated ...
12
Though what's in the Voyager remains to be seen, the Performance Study of Viterbi Decoding as Related to Space Communications1 gives a description of such a system implemented on Earth for the ground station:
It is not the prototype, it is the final version.
The prototype may have required about 4 to 8 times the volume. Not a real monster, but filling a ...
2
Question: Did the Voyager spacecraft use a Golay, a Reed-Solomon and/or a Hamming code for data transmission encoding for error correction?
Yes!
And there's a convolutional coder in there as well.
From DESCANSO Design and Performance Summary Series, Voyager Telecommunications, (2002):
The TMU [telemetry modulation unit] encodes the high rate data stream ...
131
All the different data words a transmitter can send and a receiver can detect can be imagined as dots arranged in a large space.
Selecting a data encoding for error detection and correction is about keeping valid code words at a certain distance from each other. As a result, a slight change ("movement") of a valid word doesn't make it look like ...
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