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boundary="------------DbobmjpUCuYLv02LzF0TR2Xc" Content-Language: en-US Subject: Re: [Starlink] [E-impact] DataCenters in Space (was Re: fiber IXPs in space) X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Apr 2023 21:21:32 -0000 --------------DbobmjpUCuYLv02LzF0TR2Xc Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Indeed. There's another point that's been missed in the "superconductor"=20 suggestion: Why do we get the heat in the first place? Superconductors are great when it comes to reducing resistive losses in=20 long and / or high current conductors (power distribution, MRI magnets,=20 ...). But this isn't why computer chips get hot. Let me take you back to=20 your Physics 101 when you learned that Power P was the product of=20 current I and voltage V. A logic chip like a CPU is nothing but an=20 assortment of gazillions of little switches. When a switch is open, it=20 may have voltage across it but no current flows: no power gets=20 dissipated. If it's closed, current may flow but there won't be any=20 voltage across it. Also not a source of power loss. The power loss (heat generation) happens when the little switches are=20 switching, i.e., when they are between open and closed and when there is=20 both a bit of voltage and a bit of current present. Naively you might=20 say that a switch is either on or off, and so that shouldn't occur, but=20 in both theory and practice, an instantaneous loss-free switching=20 process requires a signal of infinite bandwidth when subjected to=20 Fourier analysis. Fourier analysis allows us to model any signal as a=20 combination of sinusoidal signals of different frequency, amplitude and=20 phase, and it's in particular the high-and-in-the-direction-of-infinity=20 frequency components of that combination that are needed for the=20 "=C3=AFnstantaneous"switching. Unfortunately, in any real circuit of larger= =20 than zero size, reactive elements (capacitive and inductive components=20 or parasitic properties of that nature) attenuate these. So the only=20 real switching we can actually do in real life is switching that=20 dissipates power when it happens - no matter whether the chip is built=20 using superconductors or not. In a modern CPU, a significant percentage of gates are this this "gray"=20 in-between state between 0 and 1 for a significant part of the time,=20 which is why you need elaborate cooling fans and water coolers etc., and=20 it's also why clock frequencies haven't increased substantially in=20 recent years. On 21/04/2023 12:06 am, Dave Collier-Brown via Starlink wrote: > > Another point they missed: on earth, we can use conductive cooling and=20 > transfer the heat from the machines to a flow of air.=C2=A0 In space, we= =20 > can only use radiative cooling, and we need to be out of the sun to=20 > have enough temperature difference. > > --dave > > On 4/20/23 07:10, Hesham ElBakoury via Starlink wrote: >> The article about the ASCEND project says: >> "Very low ambient temperatures in space will dramatically reduce the=20 >> need for cooling equipment that consumes enormous amounts of energy.=20 >> A significant part of a data center=E2=80=99s energy use is for cooling= =20 >> equipment, accounting for more than 50% in some facilities.=20 >> Temperatures can be as low as -292=C2=B0F (-180=C2=B0C) when an orbiting= object=20 >> is in the Earth=E2=80=99s shadow." >> >> Hesham >> >> On Wed, Apr 19, 2023, 10:44 PM Daniel Schien=20 >> wrote: >> >> I assume any object in orbit will be hidden from the sun some of >> the time. So, the machines will require some pretty big battery >> to go up with them. >> >> I'd like to also know what the launch cost is. >> >> Tom Segert estimates in his LinkedIn post, for a=C2=A0100kg satellit= e >> payload: >> >> "TL:DR ~57 ton CO2e for a typical ESA satellite (including Ariane >> 6 launch), <15t CO2e for a satellite built in a factory and >> launched with a re-usable rocket." >> >> Depending on the type of server that should go up there, this is >> a fair amount of carbon to offset from brighter sunlight. >> >> The article also gets the carbon footprint wrong: >> >> "Data centers are big energy consumers =E2=80=93 between 2% and 3% o= f all >> global consumption =E2=80=93 a rate that is doubling every year." >> >> The latest was IEA estimating it to be around 220-320 TWh (out of >> 30,000) in 2021 data and growing between 10-60% over 6 years in >> total (so let's than 10 CAGR). But it's certainly not doubling >> every year. That's just completely wrong. >> >> >> DanielSchien >> >> Senior Lecturer in Computer Science >> >> Department of Computer Science=C2=A0| University of Bristol >> >> =09 >> =09 >> =09 >> >> *Submit software engineering project ideas for 2022* >> >> >> =09http://bris.ac.uk/software-engineering >> Watch: https://youtu.be/lU-ZsBDFWDI >> >> >> >> =09Merchant Venturers Building , Woodland Rd Bristol, BS8 1UB >> >> *Book a meeting*: >> https://outlook.office365.com/owa/calendar/OfficeHours@bristol.ac.uk= /booki >> >> >> >> >> --------------------------------------------------------------------= ---- >> *From:* E-impact on behalf of Vint >> Cerf >> *Sent:* Thursday, April 20, 2023 2:16:38 AM >> *To:* tom@evslin.com >> *Cc:* Michael Richardson ; starlink >> ; e-impact@ietf.org >> >> *Subject:* Re: [E-impact] [Starlink] DataCenters in Space (was >> Re: fiber IXPs in space) >> O&M will be a bear >> v >> >> >> On Wed, Apr 19, 2023 at 9:13=E2=80=AFPM Tom Evslin via Starlink >> wrote: >> >> I think space-based data centers will be the rule rather than >> the exception. Wrote about that a couple of years ago >> although, as usual, things have not happened as quickly as I >> predicted >> https://blog.tomevslin.com/2021/07/computing-clouds-in-orbit-a-p= ossible-roadmap.html >> >> -----Original Message----- >> From: Starlink On >> Behalf Of Michael Richardson via Starlink >> Sent: Wednesday, April 19, 2023 7:35 PM >> To: starlink ; e-impact@ietf.org >> Subject: [Starlink] DataCenters in Space (was Re: fiber IXPs >> in space) >> >> >> I saw this reported in BIS-Spaceflight. >> (I'm usually a few months behind in reading it) I like the >> "first objective"! >> >> https://www.thalesgroup.com/en/worldwide/space/press-release/asc= end-thales-alenia-space-lead-european-feasibility-study-data >> >> Cannes, November 14, 2022 =E2=80=93 Thales Alenia Space, the joi= nt >> company between Thales (67%) and Leonardo (33%), has been >> chosen by the European Commission to lead the ASCEND >> (Advanced Space Cloud for European Net zero emission and Data >> sovereignty) feasibility study for data centers in orbit, as >> part of Europe=E2=80=99s vast Horizon Europe research program. >> >> Digital technology=E2=80=99s expanding environmental footprint i= s >> becoming a major >> challenge: the burgeoning need for digitalization means that >> data centers in Europe and around the world are growing at an >> exponential pace, which in turn has a critical energy and >> environmental impact. >> >> The first objective of this study will be to assess if the >> carbon emissions from the production and launch of these >> space infrastructures will be significantly lower than the >> emissions generated by ground-based data centers, therefore >> contributing to the achievement of global carbon neutrality. >> The second objective will be to prove that it is possible to >> develop the required launch solution and to ensure the >> deployment and operability of these spaceborne data centers >> using robotic assistance technologies currently being >> developed in Europe, such as the EROSS IOD demonstrator. >> >> This project is expected to demonstrate to which extent >> space-based data centers would limit the energy and >> environmental impact of their ground counterparts, thus >> allowing major investments within the scope of Europe=E2=80=99s = Green >> Deal, possibly justifying the development of a more >> climate-friendly, reusable heavy launch vehicle. Europe could >> thus regain its leadership in space transport and space >> logistics, as well as the assembly and operations of large >> infrastructures in orbit. >> >> _______________________________________________ >> Starlink mailing list >> Starlink@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/starlink >> >> _______________________________________________ >> Starlink mailing list >> Starlink@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/starlink >> >> >> >> --=20 >> Please send any postal/overnight deliveries to: >> Vint Cerf >> Google, LLC >> 1900 Reston Metro Plaza, 16th Floor >> Reston, VA 20190 >> +1 (571) 213 1346 >> >> >> until further notice >> >> >> >> --=20 >> E-impact mailing list >> E-impact@ietf.org >> https://www.ietf.org/mailman/listinfo/e-impact >> >> >> _______________________________________________ >> Starlink mailing list >> Starlink@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/starlink > --=20 > David Collier-Brown, | Always do right. This will gratify > System Programmer and Author | some people and astonish the rest > dave.collier-brown@indexexchange.com | -- Mark Twain > > */CONFIDENTIALITY NOTICE AND DISCLAIMER/*/=C2=A0: This telecommunication,= =20 > including any and all attachments, contains confidential information=20 > intended only for the person(s) to whom it is addressed. Any=20 > dissemination, distribution, copying or disclosure is strictly=20 > prohibited and is not a waiver of confidentiality. If you have=20 > received this telecommunication in error, please notify the sender=20 > immediately by return electronic mail and delete the message from your=20 > inbox and deleted items folders. This telecommunication does not=20 > constitute an express or implied agreement to conduct transactions by=20 > electronic means, nor does it constitute a contract offer, a contract=20 > amendment or an acceptance of a contract offer. Contract terms=20 > contained in this telecommunication are subject to legal review and=20 > the completion of formal documentation and are not binding until same=20 > is confirmed in writing and has been signed by an authorized signatory./ > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > --=20 **************************************************************** Dr. Ulrich Speidel School of Computer Science Room 303S.594 (City Campus) The University of Auckland u.speidel@auckland.ac.nz =20 http://www.cs.auckland.ac.nz/~ulrich/ **************************************************************** --------------DbobmjpUCuYLv02LzF0TR2Xc Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Indeed. There's another point that's been missed in the "superconductor" suggestion: Why do we get the heat in the = first place?

Superconductors are great when it comes to reducing resistive losses in long and / or high current conductors (power distribution, MRI magnets, ...). But this isn't why computer chips get hot. Let me take you back to your Physics 101 when you learned that Power P was the product of current I and voltage V. A logic chip like a CPU is nothing but an assortment of gazillions of little switches. When a switch is open, it may have voltage across it but no current flows: no power gets dissipated. If it's closed, current may flow but there won't be any voltage across it. Also not a source of power loss.

The power loss (heat generation) happens when the little switches are switching, i.e., when they are between open and closed and when there is both a bit of voltage and a bit of current present. Naively you might say that a switch is either on or off, and so that shouldn't occur, but in both theory and practice, an instantaneous loss-free switching process requires a signal of infinite bandwidth when subjected to Fourier analysis. Fourier analysis allows us to model any signal as a combination of sinusoidal signals of different frequency, amplitude and phase, and it's in particular the high-and-in-the-direction-of-infinity frequency components of that combination that are needed for the "=C3=AFnstantaneous"switching. Unfortunately, in any real c= ircuit of larger than zero size, reactive elements (capacitive and inductive components or parasitic properties of that nature) attenuate these. So the only real switching we can actually do in real life is switching that dissipates power when it happens - no matter whether the chip is built using superconductors or not.

In a modern CPU, a significant percentage of gates are this this "gray" in-between state between 0 and 1 for a significant p= art of the time, which is why you need elaborate cooling fans and water coolers etc., and it's also why clock frequencies haven't increased substantially in recent years.  

On 21/04/2023 12:06 am, Dave Collier-Brown via Starlink wrote:
=20

Another point they missed: on earth, we can use conductive cooling and transfer the heat from the machines to a flow of air.  In space, we can only use radiative cooling, and we need to be out of the sun to have enough temperature difference.

--dave

On 4/20/23 07:10, Hesham ElBakoury via Starlink wrote:
The article about the ASCEND project says:
"Very low ambient temperatures in space wi= ll dramatically reduce the need for cooling equipment that consumes enormous amounts of energy. A significant part of a data center=E2=80=99s energy use is for cooling equipment, accounting for more than 50% in some facilities. Temperatures can be as low as -292=C2=B0F (-180=C2=B0C) when an orbiting object is in the Earth=E2=80=99s shadow."

Hesham

On Wed, Apr 19, 2023, 10:44 PM Daniel Schien <Daniel.Schien= @bristol.ac.uk> wrote:
I assume any object in orbit will be hidden from the sun some of the time. So, the machines will require some pretty big battery to go up with them. 

I'd like to also know what the launch cost is. 

Tom Segert estimates in his LinkedIn post, for a 100kg satellite payload:

"TL:DR ~57 ton CO2e for a typical ESA satellite (including Ariane 6 launch), <15t CO2e for a satellite built in a factory and launched with a re-usable rocket."

Depending on the type of server that should go up there, this is a fair amount of carbon to offset from brighter sunlight.

The article also gets the carbon footprint wrong:

"Data centers are big energy consumers =E2=80=93 between 2% and= 3% of all global consumption =E2=80=93 a rate that is doubli= ng every year."

The latest was IEA estimating it to be around 220-320 TWh (out of 30,000) in 2021 data and growing between 10-60% over 6 years in total (so let's than 10 CAGR). But it's certainly not doubling every year. That's just completely wrong.


Daniel Schi= en

Senior Lecturer in Computer Science

Department of Computer Science |=  University of Bristol

Submit software engineering project ideas for 2022

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<= font style=3D"font-size:11pt" face=3D"Calibri, sans-serif" color=3D"#000000= ">From: E-impact <e-impact-bounces@ietf.org> on behalf of Vint Cerf <vint=3D40google.com@dmarc.ietf.org&= gt;
Sent: Thursday, April 20, 2023 2:16:38 AM
To: tom@evslin.com <tom@evslin.com>
Cc: Michael Richardson <mcr@sandelman.ca>; starlink <starlink@lists.bufferbloat.net>; e-impact@ietf.org <e-impact@ietf.org>
Subject: Re: [E-impact] [Starlink] DataCenters in Space (was Re: fiber IXPs in space)
 
O&M will be a bear
v


On Wed, Apr 19, 2023 at 9:13=E2=80=AFPM = Tom Evslin via Starlink <starlink@lists.bufferbloat.net>= ; wrote:
I think space-based data centers will be the rule rather than the exception. Wrote about that a couple of years ago although, as usual, things have not happened as quickly as I predicted https://blog.tomevslin.com/2021/07/computing-clouds-in-orbit-a-possible-roa= dmap.html

-----Original Message-----
From: Starlink <starlink-bounces@lists.bufferbloa= t.net> On Behalf Of Michael Richardson via Starlink
Sent: Wednesday, April 19, 2023 7:35 PM
To: starlink <starlink@lists.bufferbloat.net>; e-impact@ietf.org
Subject: [Starlink] DataCenters in Space (was Re: fiber IXPs in space)


I saw this reported in BIS-Spaceflight.
(I'm usually a few months behind in reading it) I like the "first objective"!

https://www.thalesgroup.com/en/worldwi= de/space/press-release/ascend-thales-alenia-space-lead-european-feasibility= -study-data

Cannes, November 14, 2022 =E2=80=93 Thales Alenia Space= , the joint company between Thales (67%) and Leonardo (33%), has been chosen by the European Commission to lead the ASCEND (Advanced Space Cloud for European Net zero emission and Data sovereignty) feasibility study for data centers in orbit, as part of Europe=E2= =80=99s vast Horizon Europe research program.

Digital technology=E2=80=99s expanding environmental footprint is becoming a major
challenge: the burgeoning need for digitalization means that data centers in Europe and around the world are growing at an exponential pace, which in turn has a critical energy and environmental impact.
The first objective of this study will be to assess if the carbon emissions from the production and launch of these space infrastructures will be significantly lower than the emissions generated by ground-based data centers, therefore contributing to the achievement of global carbon neutrality. The second objective will be to prove that it is possible to develop the required launch solution and to ensure the deployment and operability of these spaceborne data centers using robotic assistance technologies currently being developed in Europe, such as the EROSS IOD demonstrator.

This project is expected to demonstrate to which extent space-based data centers would limit the energy and environmental impact of their ground counterparts, thus allowing major investments within the scope of Europe=E2=80=99s Green Deal, possibly justifying the development of a more climate-friendly, reusable heavy launch vehicle. Europe could thus regain its leadership in space transport and space logistics, as well as the assembly and operations of large infrastructures in orbit.

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David Collier-Brown,         | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
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Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

The University of Auckland
u.speidel@auckland.ac.nz=20
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