beowulf in space

Art Edwards edwardsa at plk.af.mil
Fri Apr 25 11:03:05 EDT 2003


I should also mention that there is a very large drive for radiation
hardening by design. There is work in the literature indicating that
device redesign (annular transistors, for example, to handle total dose
effects, and circuit redesign for SEU, SET) can lead to 
strategic hardening from commercial foundries. This is for digital logic
circuits. The disadvantage is that these design techniques always lead
to degradation of circuit density and of performance. However, cost
should be dramatically improved.

An issue brought up by Jim Lyke but not addressed elsewhere is cooling.
Recall that clusters generate lots of heat and that we use convection to
transfer it. In space there is either radiation or conduction. This has
to be a major focus for compact clusters that will go in space.

Art Edwards

On Thu, Apr 24, 2003 at 11:32:13PM -0500, Gerry Creager N5JXS wrote:
> One of the things I established when I was working on the old Space 
> Station Freedon, in the early '90s, is that the space-rated CPUs, less 
> the issues with radiation hardening and single-event upset recovery, 
> were hardly different from good CPUs.  What we discovered was that the 
> MIL-SPEC components differed little from the "industrial-grade" 
> components, save in the degree of paperwork delivered with the device. 
> And the costs.  Thus, we drove toward the use of the lower-cost, similar 
> quality Industrial-Grade devices.
> 
> Now, for low- and mid-earth-orbit altitudes, the radiation environment 
> is pretty harsh.  One should be cognizant of that environment, and model 
> the potential for radiation induced transient problems.  If you're not 
> ready for transient failures, and at that, failures that may or may not 
> heal (aneal), you shouldn't use non-radiation hardened, commercial, 
> processors.
> 
> I've not looked at the specs for rad-hardening and SEU performance.  If 
> it's a commercial- as opposed to an industrial-grade processor, I'd not 
> be too sure of reliability, either, although those specs have come up 
> markedly over the last 10 years.
> 
> gerry
> 
> MIDN Sean Jones wrote:
> >For reference the United States Naval Academy is putting up a PowerPC
> >405 SoC in PC/104 form factor up as the Command and Data Handling System
> >of the MidSTAR I satellite slated for launch in March 2006.
> >
> >Sean Jones
> >MIDN   USN
> >
> >MidSTAR C&DH Lead
> >Armada Cluster Asst. Admin
> >
> >On Thu, 2003-04-24 at 05:34, Jim Ahia wrote:
> >
> >>As I was reading this thread, some things came to mind that might add to
> >>the discussion:
> >>
> >>1 ) although Dells and Gateways are too heavy to lift into orbit,
> >>pc-104 systems might be the solution.  3.6 x 3.8 inch pentium-class
> >>motherboards with a single 5v power requirement make things much
> >>smaller.  It is completely possible to have each node fit into the space
> >>of a half-height CD-ROM drive.  Can anyone say "cluster in one box"?
> >>
> >>2 ) Has anyone yet mentioned the possibility of mesh networks using
> >>802.11 for robotics clustering?  Such networks of robots might make site
> >>construction, ship construction, and mining feasible.  
> >>
> >>Mining the surface of the moon is well documented to provide hydrogen,
> >>oxygen, aluminum, silica, and titanium.  Launching fuel & materials for
> >>spacecraft to an orbital construction facility might make more sense
> >>than the billions we are spending now, if the mine, transport, and
> >>construction are largely carried out by robotics under the oversight of
> >>a resident cluster with ground-based monitoring.
> >>
> >>Using a similar swarm of robots for site construction on mars prior to
> >>human arrival can have a major impact on mission success.
> >>
> >>If all robots use identical motion base and cpu, then 2 broken bots can
> >>be cannibalized to return one working bot to service.  
> >>
> >>If all of the robots that are currently recharging batteries are added
> >>to the cluster as mains-connected nodes, then a cluster of sorts is in
> >>effect to speed control processing of the 'hive'.  This is assuming that
> >>the central site has the main power supply system online, be it solar,
> >>nuc, whatever.
> >>
> >>-Jim Ahia
> >>-makenamicro at charter.net
> >>_______________________________________________
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> 
> -- 
> Gerry Creager -- gerry.creager at tamu.edu
> Network Engineering -- AATLT, Texas A&M University	
> Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.847.8578
> Page: 979.228.0173
> Office: 903A Eller Bldg, TAMU, College Station, TX 77843
> 
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-- 
Art Edwards
Senior Research Physicist
Air Force Research Laboratory
Electronics Foundations Branch
KAFB, New Mexico

(505) 853-6042 (v)
(505) 846-2290 (f)
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