Talk:NASA Deep Space Network

2008

The PDF link for "Uplink-Downlink" (the history of the DSN) points to a PDF that contains only the ToC and requires external PDF documents for its meat. How should this be handled?--Mr z 15:15, 22 September 2006 (UTC)

The additional PDF links work if you use your browser's Adobe plugin. (NOT the stand-alone program.) Muad 09:06, 17 September 2007 (UTC)

It does not appear to work at all. The PDF loads, but one cannot browse it. 24.17.252.82 (talk) 01:50, 1 November 2008 (UTC)

Works fine for me, using Firefox 3.0.3 and the latest Acroread plug-in. What programs/versions are you using that doesn't work? LouScheffer (talk) 03:21, 1 November 2008 (UTC)

Bandwidth ?

Does anyone have figures on DSN's average latency and bandwidth? 24.17.252.82 (talk) 01:50, 1 November 2008 (UTC)

For bandwidth, there is 10 MHz available at S band (2 GHz), 50 MHz at X band (8 GHz), and 500 MHz at Ka band (32 GHz). S band is mostly older missions, or those with small data requirements. X band is quite heavily used, but only a few missions are using the Ka band as yet. For latency, for all missions further than the moon, I'd guess the latency is dominated by the speed of light, and not encoding/decoding capacity. Even the nearest planets are a few light-minutes away. LouScheffer (talk) 03:57, 1 November 2008 (UTC)

Wondered Why only 10 MHz available at S band (2 GHz), 50 MHz at X band (8 GHz), and 500 MHz at Ka band (32 GHz) ?

... Deep space bands shows what's allocated by ITU to deep space science comms. Very little.

JPL split the S-band 10 MHz into 28 channels, and the X-band 50 MHz into 37 channels. - Rod57 (talk) 12:26, 15 December 2023 (UTC)

Note that for radio astronomy, the DSN typically achieves bandwidths of 1-2 GHz. It does not do this for spacecraft communication because the bands are restricted by international convention, and then the spacecraft communication feeds are optimized for these bands, and these bands only. As The DSN Radio Astronomy User's Guide states for many bands: "These systems are designed primarily for spacecraft TT&C, hence their relatively narrow bandwidths relative to current radio astronomical systems." LouScheffer (talk) 21:48, 15 December 2023 (UTC)

Photo

http://stardust.jpl.nasa.gov/photo/people.html has some better photos, e.g. Stardust Mission Operations would be better than the article'scurrent very old, very low-resolution photo. Agreed?--Elvey (talk) 03:55, 26 July 2013 (UTC)

Field of view , can spacecraft be too close

It's a little confusing but is it a general understanding that connoted intuitively the Earth's 360• view can't receive signals from close objects. Only working at distances greater then 30km? I would think unless its onscurved by a celestial object such as the moon or the sun that all satellites would be visible at all times (unless specifically designed to be stealthy). — Preceding unsigned comment added by 76.98.90.132 (talk) 17:40, 13 September 2013 (UTC)

If http://en.wikipedia.org/wiki/File:DSNantenna.svg doesn't answer your question, give up? --Elvey (talk) 01:20, 14 September 2013 (UTC)

That image implies DSN can receive from even below a 600 km LEO (when source in view of a DSN site). Rod57 (talk) 09:49, 17 December 2018 (UTC)

• The problem with close objects is due to the high gain and thus very narrow pick up range of the receiver. Think of taking a photo of the front of your house stand at the side walk with a 500mm Long-focus lens. You would not see much and it would be out of focus as the 500mm lens is designed to see objects far way. Just has Hubble Space Telescope is designed to see objects far way, thus it can not take photos of the moon or earth. Telecine Guy 22:27, 8 June 2016 (UTC)

It's not clear that DSN has that type of depth of field issue that long-focus optical lenses might have. Need a source. The problem seems to be just that close objects might not be in view of any of the 3 DSN sites. Rod57 (talk) 09:49, 17 December 2018 (UTC)

The lower the object is in orbit, the faster it crosses the sky. So at a certain point the object is just too fast and it gets harder and harder to aim and follow with the big dishes. For LEO you need smaller dishes with a wider beam that can move quicker and cover a wider angle, so thats what satellite tracking facilities are doing and are made for. Deep Space Antennas move slowly, usually according to earth rotation.--Giftzwerg 88 (talk) 01:14, 7 May 2019 (UTC)

What's the distance again?

The text embedded in http://upload.wikimedia.org/wikipedia/commons/thumb/3/31/DSNantenna.svg/300px-DSNantenna.svg.png says that the distance at which an object is always in view of 1+ antennas is 30k km.

The second paragraph of the "Deep space" section says that it's 16k km.

Is one of these a typo? Or are they discussing two different things? ("Tracking stations" versus "antenna stations" or some such?) If that's the case, some clarification by somebody qualified would be nice. 70.208.198.152 (talk) 16:54, 3 March 2014 (UTC)

• One is the min. distance 16,000 km, to be picked up. The other (30,000 km from earth) is where there is no blind spot, can switch to another stations as earth rotates. Telecine Guy 22:33, 8 June 2016 (UTC)

Why is there a min distance to be picked up ? - Rod57 (talk) 09:56, 17 December 2018 (UTC)

the earth is not flat, so the object is hidden below horizon at times.--Giftzwerg 88 (talk) —Preceding undated comment added 11:28, 11 March 2019 (UTC)

DSN and Juno Gravity Science

Why is the section "DSN and Juno Gravity Science" a top-level section? This discusses the DSN's role in a single spacecraft mission, Juno. Even supposing the Juno mission was as important as, say, the Voyager mission which is the furthest manmade object from Earth, this is still grossly UNDUE WEIGHT on one out of the hundreds of spacecraft missions the DSN services. Let's put this stuff in one of the other sections. --Chetvorno^TALK 19:34, 11 February 2017 (UTC)

Occasional use of radio astronomy antenna eg VLA

Is there a source for : "For especially vital missions, like Voyager 2, the Canberra 70-meter (230 ft) dish can be arrayed with the Parkes Radio Telescope in Australia; and the Goldstone 70-meter dish can be arrayed with the Very Large Array of antennas in New Mexico." ? - Rod57 (talk) 09:35, 17 December 2018 (UTC)

https://deepspace.jpl.nasa.gov/about/complexes/antenna-arraying/ --Giftzwerg 88 (talk) 22:13, 27 April 2019 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion

The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:

• DSNantenna.svg

Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 21:07, 4 May 2020 (UTC)

New 34-meter-wide dish at Madrid

https://www.nasa.gov/image-feature/welcoming-a-new-addition-to-the-deep-space-network

©Geni (talk) 00:30, 26 January 2021 (UTC)

Notes section

This article has a Notes section, but these aren't actual notations back to specific places in the article. They should be added with {{efn}}. MB 18:41, 27 November 2021 (UTC)

120-degree separation?

I’ve just read this twice in the article - that the three stations are 120 degrees apart. This is utter rubbish, even if you have a NASA page saying so (it says approximately but even that is untrue). If the three stations were to be 120 degrees apart, the Spanish station would be 700km to the east of Madrid, in Menorca, and the Aussie one would be in the middle of Western Australia, 2,500 km west of Canberra. This isn’t even approximately 120 degrees. Barstow to Madrid is about 112 degrees and Madrid to Canberra is about 152 degrees. Canberra to Barstow is about 96 degrees. Utter, poorly sourced rubbish. 2A02:C7C:ACA7:4600:E0FA:D71E:EFCF:178C (talk) 11:49, 15 January 2023 (UTC)

Yes, the stations are not exactly 120 degrees apart. But are they approximately 120 degrees apart? The meaning of "approximately" depends on the context - the error bars on "fingernails grow approximately 1 mm/day" are very different from "pi is approximately 3.14159". In this case the stations are indeed roughly 120 degrees apart to the accuracy needed for the point they are making, which is so that as the Earth rotates, at least one station is able to capture and transmit signals to any deep space mission without any gaps in coverage, from Why are the Deep Space Network (DSN) sites 120 degrees apart on Earth?. But since the 120 is not necessary, and could be replaced by "about a third of the way around the earth" if needed, I've edited these references out. LouScheffer (talk) 20:04, 15 January 2023 (UTC)

@LouScheffer: Thank you for removing it. Just to highlight again, 96 and 152 degrees separation is not approximately 120 degrees. To claim this is true would be the same as saying Brazil is near Canada because they’re in the same hemisphere of the world. 2A02:C7C:ACA7:4600:9077:A19:4806:1977 (talk) 17:42, 16 January 2023 (UTC)

"American spacecraft communication ground segment facilities"

I think it is an oversimplification for the initial sentence to just label the Australian and Spanish facilities "American". Here's a 2009 report by a committee of Australia's Parliament, which says "The CSIRO and the NASA jointly operate three facilities in Australia: the Canberra Deep Space Communication Complex (CDSCC) at Tidbinbilla in the ACT..." implying it is a "joint Australian-American" facility, not just "American" facility. Most of the staff at Tidbinbilla are Australian government employees; the land and buildings are owned by the Australian government; NASA provides the bulk of the funding, owns the movable property (such as dishes and electronic equipment) which it has paid for, and gets to decide what to point the dishes at (see the treaty). I know less about the details of the Spanish facility, but similar to the Australian one, it is operated by a Spanish government agency under an agreement with NASA (the National Institute for Aerospace Technology), not directly operated by NASA – so likewise it is better described as "joint American-Spanish" rather than just "American". Maybe we could call them "American-funded", which would be about as brief, but more accurate? SomethingForDeletion (talk) 00:27, 22 January 2024 (UTC)

This is a valid point, but I think it does necessarily need mention in the lede. It fits better, and can include more detail, in the management section. LouScheffer (talk) 00:48, 31 January 2024 (UTC)

I have made this change. Comments, corrections, and discussion welcome. LouScheffer (talk) 01:18, 31 January 2024 (UTC)