Author Topic: SpaceX's DSN plans  (Read 9580 times)

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2828
  • Florida
  • Liked: 1165
  • Likes Given: 76
SpaceX's DSN plans
« on: 09/22/2016 04:02 PM »
NASA/SpaceX teleconfrence recently identified a new element of SpaceX near term plans. The development of its own Deep Space Network (DSN) capabilities.

http://forum.nasaspaceflight.com/index.php?topic=41231.0

That the SpaceX DSN would be operational after a couple (probably 2022 synod) of RD missions. No longer needing NASA's DSN to support SpaceX Mars missions. This capability of broadband communications with Mars has been scattered in other threads. But this I believe is the first indication that SpaceX actually has a plan for its own DSN. What we do not know at this time is what are the plans. Hopefully the IAC talk will also touch on this subject about how the Mars occupants will keep in touch with Earth. How the large communications data requirements of multiple near simultaneous Mars missions will be accomplished.

Speculation has been using orbital assets at Mars and Earth performing an optical Laser link and then a secondary RF link from Mars orbit to Mars assets in orbit and on the surface as well as an Earth orbit to Earth surface broadband link. Much of this is based on the "CommX" large constellation speculation as a communication model for implementation at Mars with the added Interplanetary links that connect into these broadband constellations at Mars and Earth.

1) So what Earth ground assets are likely to be implemented? There is a effort at Boca Chica right now for moderate size dish emplacement. Is there likely a plan for even larger ones?

2) Orbital assets at Mars used for relays to Earth?

3) Will orbital assets be emplaced in Earth orbit?

4) How will the interplanetary broadband data requirements be met?

This thread will discuss the DSN aditional questions or speculations on the answers of questions related to the plans of a SpaceX developed DSN.
« Last Edit: 09/22/2016 05:04 PM by oldAtlas_Eguy »

Offline philw1776

  • Full Member
  • ****
  • Posts: 761
  • Seacoast NH
  • Liked: 416
  • Likes Given: 228
Re: SpaceX's DSN plans
« Reply #1 on: 09/22/2016 04:11 PM »
Looking in the context of multiple RD missions leading to landing massive amounts of cargo on Mars before manned missions all in the next decade, I would be surprised if the architecture did not utilize higher BW optical for the links from Mars to Earth orbital optical receivers.  No need for big DSN radio antennas.  The problem of communicating when the Sun is in the way for a few weeks every 26 months would be addressed later before humans land.  Interesting options abound.
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #2 on: 09/22/2016 04:13 PM »
1) So what Earth ground assets are likely to be implemented? There is a effort at Boca Chica right now for moderate size dish emplacement. Is there likely a plan for even larger ones?

I think none. Ground based assets would need dishes distributed all over earth. Like the NASA DSN. That's way too expensive.

Quote
2) Orbital assets at Mars used for relays to Earth?

I see a few sats, similar or identical to the planned small sats of the planned network in earth LEO.

Quote
3) Will orbital assets be emplaced in Earth orbit?

The planned 4000 satellite constellation. Maybe not the full number early on.

Quote
4) How will the interplanetary broadband data requirements be met?

Local satellites both in Mars and earth orbit. Laser communication between them for the interplanetary distance. Feeding into the local satellite network for ground contact.


Offline RonM

  • Senior Member
  • *****
  • Posts: 2030
  • Atlanta, Georgia USA
  • Liked: 941
  • Likes Given: 721
Re: SpaceX's DSN plans
« Reply #3 on: 09/22/2016 04:19 PM »
5) How will SpaceX deal with communication blackouts during Mars solar conjunction.

It's one thing to not be able to communicate with robots for a couple of weeks, but it is another to lose communications with a colony.

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #4 on: 09/22/2016 04:27 PM »
5) How will SpaceX deal with communication blackouts during Mars solar conjunction.

Relay sats. The points easiest to reach from earth and to keep station in are Earth-Sun L4 and L5.

Offline whitelancer64

Re: SpaceX's DSN plans
« Reply #5 on: 09/22/2016 04:33 PM »
5) How will SpaceX deal with communication blackouts during Mars solar conjunction.

It's one thing to not be able to communicate with robots for a couple of weeks, but it is another to lose communications with a colony.

I assume they would seriously consider a putting a relay satellite in a Mars-trailing orbit that would allow for comms relay around the sun during conjunction.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline ChrisC

  • Veteran
  • Full Member
  • ****
  • Posts: 1396
  • Liked: 220
  • Likes Given: 226
Re: SpaceX's DSN plans
« Reply #6 on: 09/22/2016 05:01 PM »
Just for anyone new to this, DSN = Deep Space Network.  OldAtlas_Eguy, edit into your first post above?

Also for anyone new to this, in case you haven't seen it yet, you have GOT to check out this live status of NASA's DSN system.  Click around, and don't miss the "more details" in the lower right. 
« Last Edit: 09/22/2016 05:02 PM by ChrisC »
NASA TV in HD:  history, FAQ and latest status

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #7 on: 09/22/2016 05:07 PM »
I assume they would seriously consider a putting a relay satellite in a Mars-trailing orbit that would allow for comms relay around the sun during conjunction.

Why do you favor Mars trailing over earth trailing? Earth trailing is much easier to reach.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 26451
  • Minnesota
  • Liked: 6376
  • Likes Given: 4636
Re: SpaceX's DSN plans
« Reply #8 on: 09/22/2016 05:39 PM »
The interesting thing is that this is one of the only things we already have a good handle on when it come to Mars infrastructure, the other being orbital mapping.

The 2 week blackout is relatively easy to address, but it requires a fairly dedicated spacecraft at, say, ESL3 or 4. Probably could tolerate low bandwidth for a couple weeks, but some contact would be very useful.

The Mars relay network already in place will be upgraded to optical links with or without SpaceX before SpaceX's first crewed surface mission. SpaceX's own infrastructure will add to this, but it's interesting that they don't really need to add much more, besides the aforementioned relay sat.

My guess is a satellite or three around Mars and one for the blackout period would be more than sufficient.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 7984
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 4788
  • Likes Given: 3231
Re: SpaceX's DSN plans
« Reply #9 on: 09/22/2016 05:40 PM »
I assume they would seriously consider a putting a relay satellite in a Mars-trailing orbit that would allow for comms relay around the sun during conjunction.

Why do you favor Mars trailing over earth trailing? Earth trailing is much easier to reach.
Even if the Earth local and Mars local ends are geosynch/areosynch, something has to deal with changing angles I think. If it's Earth trailing does that mean the Mars end has more angle change to deal with?

Low orbit like CommsX would use makes this worse I think? If the planet/first sat links are radio at both ends, that means fewer moving parts I think, with rf beam steering.  But how do you easily change laser beam angles without using moving parts?  just musing out loud here.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 26451
  • Minnesota
  • Liked: 6376
  • Likes Given: 4636
Re: SpaceX's DSN plans
« Reply #10 on: 09/22/2016 05:43 PM »
What WOULD be useful but isn't in place yet (other than experiments with existing relay sats) is a geolocation (areolocation) system. Doesn't have to be a full GPS-like constellation, but maybe something like the regional GNSS constellations by other nations. That'd help EDL and also make surface operations (especially robotic) much easier.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2828
  • Florida
  • Liked: 1165
  • Likes Given: 76
Re: SpaceX's DSN plans
« Reply #11 on: 09/22/2016 06:53 PM »
There is one aspect we are overlooking and that is the new emphasis by Musk and SpaceX on the Interplanetary aspects and not just Mars. Such would need a broadband DSN that can service interplanetary in general as well as Mars.

I see SpaceX's DSN effort as a broadband augmentation to the NASA DSN. Such that if everything is going normal no NASA DSN use is needed. But if a spacecraft looses contact the NASA DSN with its very powerful and sensitive receivers becomes a asset. This then allows the routine communication to be offloaded onto the SpaceX broadband DSN system which NASA could lease data bandwidth.

Offline DanielW

  • Full Member
  • ****
  • Posts: 434
  • L-22
  • Liked: 288
  • Likes Given: 59
Re: SpaceX's DSN plans
« Reply #12 on: 09/22/2016 07:26 PM »
There is one aspect we are overlooking and that is the new emphasis by Musk and SpaceX on the Interplanetary aspects and not just Mars. Such would need a broadband DSN that can service interplanetary in general as well as Mars.

I see SpaceX's DSN effort as a broadband augmentation to the NASA DSN. Such that if everything is going normal no NASA DSN use is needed. But if a spacecraft looses contact the NASA DSN with its very powerful and sensitive receivers becomes a asset. This then allows the routine communication to be offloaded onto the SpaceX broadband DSN system which NASA could lease data bandwidth.

I would not read too much into the interplanetary stuff. I read that as musk the overgrown child saying

"Sweet, The requirements for fast transit to Mars also fit the requirements for other destinations! How cool is that?"

I suspect that they will not go out of their way to enable other destinations specifically in the design unless it is really low hanging fruit that does not add cost or complexity.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2828
  • Florida
  • Liked: 1165
  • Likes Given: 76
Re: SpaceX's DSN plans
« Reply #13 on: 09/22/2016 07:54 PM »
There is one aspect we are overlooking and that is the new emphasis by Musk and SpaceX on the Interplanetary aspects and not just Mars. Such would need a broadband DSN that can service interplanetary in general as well as Mars.

I see SpaceX's DSN effort as a broadband augmentation to the NASA DSN. Such that if everything is going normal no NASA DSN use is needed. But if a spacecraft looses contact the NASA DSN with its very powerful and sensitive receivers becomes a asset. This then allows the routine communication to be offloaded onto the SpaceX broadband DSN system which NASA could lease data bandwidth.

I would not read too much into the interplanetary stuff. I read that as musk the overgrown child saying

"Sweet, The requirements for fast transit to Mars also fit the requirements for other destinations! How cool is that?"

I suspect that they will not go out of their way to enable other destinations specifically in the design unless it is really low hanging fruit that does not add cost or complexity.
In order to communicate to all those SpaceX spacecraft in transit they have to implement the general case of tracking and communicating with individual spacecraft. So to make it able to reach out further is a little more ERP (effective radiated power) and receiver gain. For optics a larger telescope. The more gain margin the better.

So yes interplanetary support is just another low hanging fruit not requiring different systems just more margins in required systems.

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #14 on: 09/22/2016 08:27 PM »
I doubt that SpaceX is planning to do anything like this. Their goal will remain Mars. If anyone wants to go elsewhere it is his responsibility to provide things like communications. In most cases they will fall back to the DSN.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2828
  • Florida
  • Liked: 1165
  • Likes Given: 76
Re: SpaceX's DSN plans
« Reply #15 on: 09/22/2016 09:19 PM »
I doubt that SpaceX is planning to do anything like this. Their goal will remain Mars. If anyone wants to go elsewhere it is his responsibility to provide things like communications. In most cases they will fall back to the DSN.
Probably. And even SpaceX for Mars would fall back to the NASA DSN for the non-normal communications cases. But for the normal high data rate case SpaceX would put in and use their own system because nothing exists to do that.

Offline ThereIWas3

  • Full Member
  • ****
  • Posts: 592
  • Liked: 244
  • Likes Given: 208
Re: SpaceX's DSN plans
« Reply #16 on: 09/22/2016 10:15 PM »
I don't know how many dishes the NASA DSN has but it is not a lot and they have to handle all of the still operating planetary missions.  If SpaceX builds its own dedicated Earth-Mars link system it can guarantee pretty much continuous coverage, with appropriate relays to handle the Sun plus planet rotations.
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline ChrisC

  • Veteran
  • Full Member
  • ****
  • Posts: 1396
  • Liked: 220
  • Likes Given: 226
Re: SpaceX's DSN plans
« Reply #17 on: 09/23/2016 02:41 AM »
I don't know how many dishes the NASA DSN has

The answer is two clicks away, via a link I posted in a comment above.

Yes, they are busy, pretty much around the clock.  But it's getting quieter since just about all the New Horizons data from the Pluto flyby is finally down.  And a year or two from now it's going to get downright calm as Cassini and Juno both end their missions, resulting in ZERO missions at or even heading towards the outer giant planets.  Funding has consequences ...
« Last Edit: 09/23/2016 02:50 AM by ChrisC »
NASA TV in HD:  history, FAQ and latest status

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #18 on: 09/23/2016 03:40 AM »
1) So what Earth ground assets are likely to be implemented? There is a effort at Boca Chica right now for moderate size dish emplacement. Is there likely a plan for even larger ones?
For tracking and navigation, you need global continuous coverage, 3 dishes.
Orion - the first and only manned not-too-deep-space craft

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #19 on: 09/23/2016 05:47 AM »
1) So what Earth ground assets are likely to be implemented? There is a effort at Boca Chica right now for moderate size dish emplacement. Is there likely a plan for even larger ones?
For tracking and navigation, you need global continuous coverage, 3 dishes.

The data can be fed into the planned internet sat constellation. No need for big ground stations anywhere. Just route them to where you need them and download with a pizza box sized device.

Offline UberNobody

  • Full Member
  • *
  • Posts: 121
  • Liked: 58
  • Likes Given: 46
Re: SpaceX's DSN plans
« Reply #20 on: 09/23/2016 06:11 AM »
What kind of bandwidth are we talking about?  Megabits, hundreds of megabits, gigabits?  What are the limiting factors?

We need at least 6 live camera angles of the first manned landing, each one using 8k RED cameras ;) ;D

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #21 on: 09/23/2016 07:06 AM »
1) So what Earth ground assets are likely to be implemented? There is a effort at Boca Chica right now for moderate size dish emplacement. Is there likely a plan for even larger ones?
For tracking and navigation, you need global continuous coverage, 3 dishes.

The data can be fed into the planned internet sat constellation. No need for big ground stations anywhere. Just route them to where you need them and download with a pizza box sized device.
I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.
Orion - the first and only manned not-too-deep-space craft

Offline AncientU

  • Senior Member
  • *****
  • Posts: 4305
  • Liked: 2578
  • Likes Given: 3605
Re: SpaceX's DSN plans
« Reply #22 on: 09/23/2016 07:28 AM »
I assume they would seriously consider a putting a relay satellite in a Mars-trailing orbit that would allow for comms relay around the sun during conjunction.

Why do you favor Mars trailing over earth trailing? Earth trailing is much easier to reach.
Even if the Earth local and Mars local ends are geosynch/areosynch, something has to deal with changing angles I think. If it's Earth trailing does that mean the Mars end has more angle change to deal with?

Low orbit like CommsX would use makes this worse I think? If the planet/first sat links are radio at both ends, that means fewer moving parts I think, with rf beam steering.  But how do you easily change laser beam angles without using moving parts?  just musing out loud here.

Changing angles are required no matter if RF or optical... Earth rotation, eclipses, and orbital mechanics make moving parts and multiple lines of sight a feature of any system.  GSO simplifies problem somewhat by mostly eliminating the eclipses.  Both RF and Optical have high directionality requirements, RF to get the needed gain and laser on both ends to establish and maintain the link.
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #23 on: 09/23/2016 07:42 AM »
I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.

I don't think you quite understand how specific Mars communication with laser com sats from orbit to orbit will work.

Offline Hobbes-22

  • Full Member
  • ***
  • Posts: 346
  • Acme Engineering
    • Acme Engineering shop
  • Liked: 97
  • Likes Given: 74
Re: SpaceX's DSN plans
« Reply #24 on: 09/23/2016 07:51 AM »
Has laser communication been demonstrated at that distance yet?

Offline AncientU

  • Senior Member
  • *****
  • Posts: 4305
  • Liked: 2578
  • Likes Given: 3605
Re: SpaceX's DSN plans
« Reply #25 on: 09/23/2016 08:28 AM »
Has laser communication been demonstrated at that distance yet?

Moon (Lunar orbit) to ground is best yet, I believe -- LADEE*.  One experiment APOLLO** links Earth to Lunar reflectors and back to 3.5m telescope counting individual photons, so theory behind comms is well established.

Pointing/acquisition is a solved problem.  Signal strength and data rate are trivially scaled in space; larger mirrors as collectors also trivially calculated, but harder to implement.  Down link through atmosphere is fairly trivial -- up link not so much because atmosphere distortions have much greater impact if on first segment of link instead of final segment.

*, **Links:
https://www.nasa.gov/sites/default/files/llcdfactsheet.final_.web_.pdf
http://www.physics.ucsd.edu/~tmurphy/apollo/apollo.html
« Last Edit: 09/23/2016 08:31 AM by AncientU »
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline Bob Shaw

  • Full Member
  • ****
  • Posts: 952
  • Liked: 355
  • Likes Given: 326
Re: SpaceX's DSN plans
« Reply #26 on: 09/23/2016 09:16 AM »
How will optical communication systems cope with the generally (and sometimes *very*) dusty Martian atmosphere?

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #27 on: 09/23/2016 09:20 AM »
How will optical communication systems cope with the generally (and sometimes *very*) dusty Martian atmosphere?

At least I don't suggest laser communication from and to any planetary surface.

My suggestion was for the interplanetary distance. With ground to orbit covered the way planned for the large array of small satellites.

Offline AncientU

  • Senior Member
  • *****
  • Posts: 4305
  • Liked: 2578
  • Likes Given: 3605
Re: SpaceX's DSN plans
« Reply #28 on: 09/23/2016 11:17 AM »
How will optical communication systems cope with the generally (and sometimes *very*) dusty Martian atmosphere?

At least I don't suggest laser communication from and to any planetary surface.

My suggestion was for the interplanetary distance. With ground to orbit covered the way planned for the large array of small satellites.

I agree that RF comms are simplest to the surface... beamforming/signal relaying LMO sats should use same technology as planned LEO constellations.  Mobile surface platforms/individualy would not need to carry sat tracking hardware.

High data rate to/from the surface from fixed ground assets could generally use 1550 nm commercial laser which is fairly penetrating through dust, plus there is never significant atmospheric blurring (seeing) or thick cloud layers as on Earth.  This should prove to be much less challenging than Earth uplinking.
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline docmordrid

  • Senior Member
  • *****
  • Posts: 4193
  • Michigan
  • Liked: 1365
  • Likes Given: 1
Re: SpaceX's DSN plans
« Reply #29 on: 09/23/2016 01:47 PM »
NASA solar system internet using DTN networks

NASA article...

« Last Edit: 09/23/2016 01:49 PM by docmordrid »
DM

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 26451
  • Minnesota
  • Liked: 6376
  • Likes Given: 4636
Re: SpaceX's DSN plans
« Reply #30 on: 09/23/2016 01:50 PM »
Initially, use the standard UHF Mars radio that the existing Mars fleet uses for surface-orbit comms.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 7984
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 4788
  • Likes Given: 3231
Re: SpaceX's DSN plans
« Reply #31 on: 09/23/2016 02:52 PM »
I assume they would seriously consider a putting a relay satellite in a Mars-trailing orbit that would allow for comms relay around the sun during conjunction.

Why do you favor Mars trailing over earth trailing? Earth trailing is much easier to reach.
Even if the Earth local and Mars local ends are geosynch/areosynch, something has to deal with changing angles I think. If it's Earth trailing does that mean the Mars end has more angle change to deal with?

Low orbit like CommsX would use makes this worse I think? If the planet/first sat links are radio at both ends, that means fewer moving parts I think, with rf beam steering.  But how do you easily change laser beam angles without using moving parts?  just musing out loud here.

Changing angles are required no matter if RF or optical... Earth rotation, eclipses, and orbital mechanics make moving parts and multiple lines of sight a feature of any system.  GSO simplifies problem somewhat by mostly eliminating the eclipses.  Both RF and Optical have high directionality requirements, RF to get the needed gain and laser on both ends to establish and maintain the link.
Yes, changing angles are required no matter what. What I was driving at was: do certain design choices (which satellites are geo/areo synch, for example) reduce the amount of mechanical angle change compared to other design choices? I believe (based on gut) that mechanical angle changes (laser) are harder, more prone to failure, than radiative angle changes. But I could be all wet.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #32 on: 09/23/2016 03:50 PM »
I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.

I don't think you quite understand how specific Mars communication with laser com sats from orbit to orbit will work.

I'm eager to learn though. I mean, how does a currently functioning laser relay network like European EDRS have any inputs to spacecraft navigation ?
Specifically, without ground antennae and signal processing centers, how does one compute precise spacecraft velocity and location for example before and after mid-course trajectory correction maneuvers ?
Did someone invent a replacement for Delta-DOR, which replaces DOR correlators , VLBI receivers and all the other  equipment currently required for this ?
Orion - the first and only manned not-too-deep-space craft

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #33 on: 09/23/2016 04:18 PM »
I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.

I don't think you quite understand how specific Mars communication with laser com sats from orbit to orbit will work.

I'm eager to learn though. I mean, how does a currently functioning laser relay network like European EDRS have any inputs to spacecraft navigation ?
Specifically, without ground antennae and signal processing centers, how does one compute precise spacecraft velocity and location for example before and after mid-course trajectory correction maneuvers ?
Did someone invent a replacement for Delta-DOR, which replaces DOR correlators , VLBI receivers and all the other  equipment currently required for this ?

I was under the impression we are talking about high throughput data communications between earth and Mars.

You are now talking about something else entirely. Something that I believe may need radio communication between spacecraft and the ground on earth with rather low throughput.

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #34 on: 09/23/2016 04:20 PM »
I was under the impression we are talking about high throughput data communications between earth and Mars.

You are now talking about something else entirely. Something that I believe may need radio communication between spacecraft and the ground on earth with rather low throughput.

Let me bold :
1) So what Earth ground assets are likely to be implemented? There is a effort at Boca Chica right now for moderate size dish emplacement. Is there likely a plan for even larger ones?
For tracking and navigation, you need global continuous coverage, 3 dishes.


I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.

Orion - the first and only manned not-too-deep-space craft

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #35 on: 09/23/2016 04:27 PM »
I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.

So again, you have introduced an entirely new requirement into the discussion. My understanding remains that we are talking about a high speed data communications network between earth and Mars. You want to burden that with a totally different requirement. A sure way to increase cost and complexity while probably reducing capability.

Offline RonM

  • Senior Member
  • *****
  • Posts: 2030
  • Atlanta, Georgia USA
  • Liked: 941
  • Likes Given: 721
Re: SpaceX's DSN plans
« Reply #36 on: 09/23/2016 04:42 PM »
I don't think you quite understand why Goldstone, Canberra and Madrid have 70m antennaes and what role do these things play in getting spacecraft going to where they need to be going.

So again, you have introduced an entirely new requirement into the discussion. My understanding remains that we are talking about a high speed data communications network between earth and Mars. You want to burden that with a totally different requirement. A sure way to increase cost and complexity while probably reducing capability.

The NASA DSN is used track to spacecraft position and velocity for navigation. Unless SpaceX is planning to use something like the NASA test DSAC, the SpaceX DSN will also have to be able to track spacecraft for navigation.

http://www.nasa.gov/mission_pages/tdm/clock/overview.html

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #37 on: 09/23/2016 04:44 PM »
So again, you have introduced an entirely new requirement into the discussion.
I'm sorry : spacecraft tracking remains one of the most critical functions of a DSN network, any DSN - including Chinese, ESA, Indian and Japanese DSN networks. The other critical functionalities being command uplink and telemetry reception. I don't know what discussion of 'a DSN' would neglect these.
Orion - the first and only manned not-too-deep-space craft

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #38 on: 09/23/2016 04:46 PM »
The NASA DSN is used track to spacecraft position and velocity for navigation. Unless SpaceX is planning to use something like the NASA test DSAC, the SpaceX DSN will also have to be able to track spacecraft for navigation.
DSAC alone would not replace DSN based tracking and navigation functionality. It would help navigation though
Orion - the first and only manned not-too-deep-space craft

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 26451
  • Minnesota
  • Liked: 6376
  • Likes Given: 4636
Re: SpaceX's DSN plans
« Reply #39 on: 09/23/2016 04:56 PM »
You could imagine an all-optical system for tracking and navigation as well as data transmission. Or a radio-based but all-in-orbit system for tracking and navigation that wouldn't require huge ground dishes.

If they go optical for bulk data transmission, I'd bet a hybrid system. They use radio for low-bandwidth commanding and rough tracking, then use optical for fine position tracking and bulk data transfer. Could use much smaller ground dishes.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline avollhar

  • Full Member
  • *
  • Posts: 129
  • Liked: 30
  • Likes Given: 22
Re: SpaceX's DSN plans
« Reply #40 on: 09/23/2016 05:08 PM »
DSN is doing navigation and communications.. same for ESA ESTRACK. I would state, that communication is easy.. but navigation (especially when trying to hit an entry corridor for Mars entry) is awfully hard!

Been there, done that..

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #41 on: 09/23/2016 05:56 PM »
I would state, that communication is easy.. but navigation (especially when trying to hit an entry corridor for Mars entry) is awfully hard!

Been there, done that..

This is what most people aren't aware of. Thanks
Orion - the first and only manned not-too-deep-space craft

Offline AncientU

  • Senior Member
  • *****
  • Posts: 4305
  • Liked: 2578
  • Likes Given: 3605
Re: SpaceX's DSN plans
« Reply #42 on: 09/23/2016 06:04 PM »
I would state, that communication is easy.. but navigation (especially when trying to hit an entry corridor for Mars entry) is awfully hard!

Been there, done that..

This is what most people aren't aware of. Thanks

Doesn't the tracking function depend on two or more stations having near simultaneous contact?  Timing for the signal plus sighting angle provides the position of space vehicle; RF photons travel same speed as 1550nm photons, so timing is same problem in each.  Baseline restrictions for ground systems (Earth diameter minus limiting antenna altitude) seems much more restrictive than two GEO laser-comm sats where the baseline is ten times as large potentially, and simultaneous/continuous position tracking is possible.  DSN does have the advantage of being used for last 50 years, though, while laser comms is still on the drawing board.

Note that the APOLLO Lunar ranging experiment mentioned above measures Lunar distance down to <centimeter scale, so laser tracking could potentially do as well as needed with a spacecraft.
« Last Edit: 09/23/2016 06:16 PM by AncientU »
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #43 on: 09/23/2016 06:10 PM »
I would state, that communication is easy.. but navigation (especially when trying to hit an entry corridor for Mars entry) is awfully hard!

Been there, done that..

This is what most people aren't aware of. Thanks

Doesn't the tracking function depend on two or more stations having near simultaneous contact?  ..

Yes it does, for VLBI. Delta-DOR works off of Goldstone-Canberra or Goldstone-Madrid baselines
Orion - the first and only manned not-too-deep-space craft

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #44 on: 09/23/2016 06:28 PM »
You could imagine an all-optical system for tracking and navigation as well as data transmission. Or a radio-based but all-in-orbit system for tracking and navigation that wouldn't require huge ground dishes.
Can you point to any research or other works about how exactly would this work ? Especially, what replaces quasar based error correction ?
Orion - the first and only manned not-too-deep-space craft

Offline LouScheffer

  • Full Member
  • ****
  • Posts: 1499
  • Liked: 1644
  • Likes Given: 185
Re: SpaceX's DSN plans
« Reply #45 on: 09/29/2016 02:13 AM »
SpaceX already has a huge number of problems on their plate, and the DSN problem has known technical solutions that are not that expensive by Mars exploration standards.  I'd be very tempted to start by simply copying the known DSN technology, already known to solve tracking, commanding, emergency telemetry, and data downlink.  According to Contract Marks New Generation for Deep Space Network, a pair of 34 meter antennas runs about $40M.  Put a pair (for redundancy) in California, Spain, and Australia just like the DSN does.  You can buy off the shelf low noise amps, transmitters, space-qualified transponders, and almost all the other stuff you'll need.  Use the CCSDS standard deep space protocols so the DSN and ESA can back you up in an emergency.   This would also enable you to offer bandwidth to scientific missions when you are not using all your bandwidth for SpaceX.  This would earn you the gratitude of scientists everywhere, since the DSN is always over-subscribed.

When they are actually ready to send humans, then SpaceX could build the high bandwidth optical links, if the other space agencies have not done so yet (they are all working on it).

Online savuporo

  • Senior Member
  • *****
  • Posts: 4942
  • Liked: 861
  • Likes Given: 309
Re: SpaceX's DSN plans
« Reply #46 on: 09/29/2016 02:54 AM »
SpaceX already has a huge number of problems on their plate, and the DSN problem has known technical solutions that are not that expensive by Mars exploration standards.  I'd be very tempted to start by simply copying the known DSN technology, already known to solve tracking, commanding, emergency telemetry, and data downlink.  According to Contract Marks New Generation for Deep Space Network, a pair of 34 meter antennas runs about $40M.  Put a pair (for redundancy) in California, Spain, and Australia just like the DSN does.  You can buy off the shelf low noise amps, transmitters, space-qualified transponders, and almost all the other stuff you'll need.  Use the CCSDS standard deep space protocols so the DSN and ESA can back you up in an emergency.   This would also enable you to offer bandwidth to scientific missions when you are not using all your bandwidth for SpaceX.  This would earn you the gratitude of scientists everywhere, since the DSN is always over-subscribed....

Couldn't agree more with this. But i don't think they actually have that much cash to spare on things like these, and it's not a one off investment either, coming with significant facilities upkeep.
Here is where a reasonable public-private co-investment strategy should come into play, but somehow that sounds unlikely too.
Orion - the first and only manned not-too-deep-space craft

Offline LouScheffer

  • Full Member
  • ****
  • Posts: 1499
  • Liked: 1644
  • Likes Given: 185
Re: SpaceX's DSN plans
« Reply #47 on: 09/29/2016 03:41 AM »
SpaceX already has a huge number of problems on their plate, and the DSN problem has known technical solutions that are not that expensive by Mars exploration standards.  I'd be very tempted to start by simply copying the known DSN technology,[...] Use the CCSDS standard deep space protocols so the DSN and ESA can back you up in an emergency.   This would also enable you to offer bandwidth to scientific missions when you are not using all your bandwidth for SpaceX.  This would earn you the gratitude of scientists everywhere, since the DSN is always over-subscribed....

Couldn't agree more with this. But i don't think they actually have that much cash to spare on things like these, and it's not a one off investment either, coming with significant facilities upkeep.
Here is where a reasonable public-private co-investment strategy should come into play, but somehow that sounds unlikely too.
I suspect the upkeep could be covered by renting out unused time to JPL and/or missions that want more bandwidth.  The standard DSN rate is $1057 per hour for a 34 meter antenna, and they have more demand than they can handle at that cost.  If SpaceX charges half of that, to get folks to use their facilities, they'd still get about $4M/year/antenna.   Not a big profit, but probably enough to cover upkeep.

Offline mikelepage

Re: SpaceX's DSN plans
« Reply #48 on: 03/16/2017 08:25 AM »
A side use of the cis-lunar tourism flights could be the deployment of communications relay satellites into heliocentric orbits.  Wouldn't take much extra dV following TLI to put any sat on a lunar flyby that results in Earth escape velocity.
 

Offline Glom

  • Member
  • Posts: 35
  • England
  • Liked: 9
  • Likes Given: 0
Re: SpaceX's DSN plans
« Reply #49 on: 03/16/2017 11:51 AM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6189
  • Germany
  • Liked: 1528
  • Likes Given: 1286
Re: SpaceX's DSN plans
« Reply #50 on: 03/16/2017 12:47 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

DSN covers the whole solar system with its spread out probes. It has very large dishes in a number of locations spread over the earth.

SpaceX is interested in Mars capabilities. They could increase data flow from Mars and maybe relieve the DSN from some work there.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31065
  • Cape Canaveral Spaceport
  • Liked: 9226
  • Likes Given: 295
Re: SpaceX's DSN plans
« Reply #51 on: 03/16/2017 01:02 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

What is a QinetiQ?
And why would Spacex be any better than anyone else at running the DSN?
And why would Space want to run the DSN?
« Last Edit: 03/16/2017 01:03 PM by Jim »

Offline Eer

  • Full Member
  • **
  • Posts: 272
  • Liked: 140
  • Likes Given: 126
Re: SpaceX's DSN plans
« Reply #52 on: 03/16/2017 01:05 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

DSN covers the whole solar system with its spread out probes. It has very large dishes in a number of locations spread over the earth.

SpaceX is interested in Mars capabilities. They could increase data flow from Mars and maybe relieve the DSN from some work there.

But the more general answer might be that someone, not necessarily SpaceX, could offer/bid to do so, particularly if it allowed NASA to shift to a more commercial-oriented basis for the services, and let the new entity also contract to serve SpaceX, Beos, Planetary Resources (if/when), ESA, etc.  It would require care to address international consumers data and service requirements (including privacy) while also being able to support the service during relatively low levels of activity. 

May be a bit early, but not too early for early adopters to be thinking how to do.

Offline JamesH65

  • Full Member
  • ****
  • Posts: 560
  • Liked: 301
  • Likes Given: 7
Re: SpaceX's DSN plans
« Reply #53 on: 03/16/2017 02:00 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

What is a QinetiQ?
And why would Spacex be any better than anyone else at running the DSN?
And why would Space want to run the DSN?

Surprised you haven't heard of QuinetiQ, formally part of DERA. But I guess it's not an American company....

https://www.qinetiq.com/about-us/Pages/default.aspx


Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31065
  • Cape Canaveral Spaceport
  • Liked: 9226
  • Likes Given: 295
Re: SpaceX's DSN plans
« Reply #54 on: 03/16/2017 02:06 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

What is a QinetiQ?
And why would Spacex be any better than anyone else at running the DSN?
And why would Space want to run the DSN?

Surprised you haven't heard of QuinetiQ, formally part of DERA. But I guess it's not an American company....

https://www.qinetiq.com/about-us/Pages/default.aspx



I know the company very well but not "do a QinetiQ"?

Offline LouScheffer

  • Full Member
  • ****
  • Posts: 1499
  • Liked: 1644
  • Likes Given: 185
Re: SpaceX's DSN plans
« Reply #55 on: 03/21/2017 02:37 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?
NASA has already done this, at least in terms of day-to-day operation. From the Inspector General's report NASA’S MANAGEMENT OF THE DEEP SPACE NETWORK:
Quote
Exelis, Inc., a private contractor specializing in support for space networks, is responsible for on-site management of Goldstone as part of its 5-year, $218.2 million subcontract with JPL. In FY 2014, Exelis had an annual operating budget of $16.8 million for Goldstone and employed about 150 people.
And Spain:
Quote
Ingenieria de Sistemas para la Defensa de España S.A. (ISDEFE), a wholly owned subsidiary of the Instituto Nacional de Técnica Aeroespacial (INTA) and a part of the Spanish Department of Defense, operates and maintains the Madrid Deep Space Communications Complex (Madrid).
Likewise, operation of the Australia complex is done by CSIRO.
Quote
The Commonwealth Scientific and Industrial Research Organisation (CSIRO), an Australian Commonwealth Government Statutory Authority, established the CSIRO Astronomy and Space Science Division to manage the day-to-day operations, engineering, and maintenance activities of the Canberra Deep Space Communications Complex (Canberra).

Offline Hobbes-22

  • Full Member
  • ***
  • Posts: 346
  • Acme Engineering
    • Acme Engineering shop
  • Liked: 97
  • Likes Given: 74
Re: SpaceX's DSN plans
« Reply #56 on: 03/21/2017 02:52 PM »
Could NASA do a QinetiQ and sign a long term agreement for SpaceX to run the DSN for them?

What is a QinetiQ?
And why would Spacex be any better than anyone else at running the DSN?
And why would Space want to run the DSN?

Surprised you haven't heard of QuinetiQ, formally part of DERA. But I guess it's not an American company....

https://www.qinetiq.com/about-us/Pages/default.aspx



I know the company very well but not "do a QinetiQ"?

Qinetiq is the somewhat-controversial conversion of a government department (tasked with research for defence) to a commercial company, now partly in foreign hands.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31065
  • Cape Canaveral Spaceport
  • Liked: 9226
  • Likes Given: 295
Re: SpaceX's DSN plans
« Reply #57 on: 03/21/2017 03:08 PM »

Exelis, Inc., a private contractor specializing in support for space networks, is responsible for on-site management of Goldstone as part of its 5-year, $218.2 million subcontract with JPL. In FY 2014, Exelis had an annual operating budget of $16.8 million for Goldstone and employed about 150 people.


Been that way for many years.  Most NASA day to day ops are done by contractors.  Even TDRSS.

Tags: