) (03/07/91)
Excuse me for my ignorance in this matter, but I'm still a student and I find it completely unbelievable that NASA are using technology that even 'toy' home computers no longer use... Core memories???? I was under the impression they went out about the same time as gas street lights and computers that took up a whole building just to add two numbers ! Magnetic Tape???? what about disks????? even floppies, with up to 20MB on a single 3.5" provide a sturdier, more convenient answer.. and how about the DATAPac technology? 100MB and more hard disks, especially suited to being roughed around? (thats the ones where you plug them out of one computer, sling them in your brief case, shake them to bits on the subway, then plug them into another machine, and the data is 100% guaranteed) I would be looking at, AT THE LEAST, radiation hardened datapacs, storing the flight programs (with 3 backups,each one oriented a different way so that a sharp manuver that might just crash the heads on one will only move them on another) I would expect radiation hardened processors, of an industry sstandard type (80x86, or 680x0 series) for easy replacement, and a well tested and trusted product. As has been suggested by someone else already, EAROMS or just straight ROMS can be used for holding much of the non changing code in memory during a flight. as for RAM needs, if in 1991, the leading manufacturers of semiconductors can put upwards of 10^6 transistors on a chip, but can't make radiation resistant store, then we shouldn't be puttin people into space, we should be putting them into the space inside some peoples heads, to find the technology we need!!!! Theora. -- sig (made it through the ethernet alive!) ================================================================================ Theora Jones Strathclyde University, SCOTLAND || " I can fly higher than an CABP10@uk.ac.strath.vaxa (somewhere on JANET) || Eagle, with you as the CABP10%vaxa.strath.ac.uk (elsewhere, hopefully) || wind beneath my wings " CABP10%vaxa.strath.ac.uk@ukacrl (just might work)|| 8:-) 1990 WE SUPPORTED DESERT STORM ! KUWAIT IS NOW FREE ! || "Lets be MAWS!" ================================================================================
dil@mace.cc.purdue.edu (Perry G Ramsey) (03/10/91)
In article <1991Mar7.142311.10412@vaxa.strath.ac.uk>, cabp10@vaxa.strath.ac.uk (Theora Jones, In Person!) writes: > > Excuse me for my ignorance in this matter, but I'm still a student and I find > it completely unbelievable that NASA are using technology that even 'toy' > home computers no longer use... > Core memories???? I was under the impression they went out about the same time > as gas street lights and computers that took up a whole building just to add > two numbers ! > Magnetic Tape???? what about disks????? even floppies, with up to 20MB on a The paperwork needed to order the change would fill TWO buildings. To be a little more fair, they have a very complex vehicle. It is important to make sure that changes don't affect the system in unexpected ways, so it takes a lot of integration engineering and testing to do that. They've just gone overboard with the principle. Working with outdated equipment just because it was available off the shelf in 1974 ends up being a safety hazard, because you can't incorporate advances in capability. Besides the fact that NASA is supposed to be pushing technology if their existence is to have any value to the taxpayers. The state of the Shuttle GPC indicates pretty clearly that the current NASA (at least the manned space side) is scared to death of anything new. That, though, is the ultimate state of any hidebound bureaucracy: it's better not to make a mistake than not to accomplish anything. -- Perry G. Ramsey Department of Earth and Atmospheric Sciences perryr@vm.cc.purdue.edu Purdue University, W. Lafayette, IN USA dil@mace.cc.purdue.edu *** IMAGINE YOUR LOGO HERE ****** Ten thousand low-lifes a day read this space.
rnm8s@helga4.acc.Virginia.EDU (Rory Neil Mcleod) (03/11/91)
Theora: The computers on board the shuttle aren't the only pieces of equipment that are out dated and used on the shuttle or used to get the bird launched. With notable exceptions, the equipments used to launch the shuttle is the same as it was designed in the late '70's. There is of course, good reason for this: each piece of equipment must be tested and all of its failure modes well known. Once a system is in place, and it works, it is not likely to be replaced. It takes either failure or poor performance to get the anyone interested in changing something. The Environmental Control System (ECS), of which most of the equipment is located underneath the launch pad, is largley comprised of Apollo era equipment. It works, and, just as importantly, everyone who works on the system knows ALOT about it. Of course, the Bureacracy tends to slow the rate at which changes are made, but, the STS is a huge system, what may seem like a little change to one system may have a major impact someplace else. The checks and balances are there for a reason. Rory McLeod Dept Mechanical and Aerospace Engineering University of Virginia Ex-NASA KSC ECS&PVD TV-MSD-13
ricci@cbmvax.commodore.com (Mark Ricci - CATS) (03/12/91)
In article <1991Mar7.142311.10412@vaxa.strath.ac.uk> cabp10@vaxa.strath.ac.uk (Theora Jones, In Person!) writes: > > Excuse me for my ignorance in this matter, but I'm still a student and I find >it completely unbelievable that NASA are using technology that even 'toy' >home computers no longer use... I spent eight years programming for various defense firms and I was told that the military is reluctant to switch to new technologies for existing programs without an awful lot of testing. They seem to prefer old and known to new and unknown. It doesn't make a lot of sense in some ways, but then again, you're talking about people's lives and there is going to be a certain amount of overkill when it comes to safety. Of course, for a new program, they will include as many new and exotic technologies as possible. :^) Mark -- ============================================================================= Mark Ricci - CATS | "I don't think so! Homey don't play dat." Commodore Applications and | Technical Support | - Homey the Clown ricci@cbmvax.commodore.com | In Living Color ==============================================================================
phil@eecs.nwu.edu (William LeFebvre) (03/12/91)
In article <6963@mace.cc.purdue.edu>, dil@mace.cc.purdue.edu (Perry G Ramsey) writes: |> To be a little more fair, they have a very complex vehicle. It is |> important to make sure that changes don't affect the system in unexpected |> ways... especially since any such "unexpected" behavior could cost us up to seven lives. |> They've just gone overboard with the principle. That's a matter of opinion. |> Working with outdated |> equipment just because it was available off the shelf in 1974 ends up |> being a safety hazard, because you can't incorporate advances in capability. I don't see that as a "safety hazard". An impediment to progess, yes. And perhaps an impediment to *increasing* the level of safety. |> Besides the fact that NASA is supposed to be pushing technology if their |> existence is to have any value to the taxpayers. The state of the Shuttle GPC |> indicates pretty clearly that the current |> NASA (at least the manned space side) is scared to death of anything new. If you want to see NEW technology being used at NASA, check out the UNmanned projects. They aren't afraid to use new technology. Why? because the worst that can happen is we lose an expensive piece of equipment. If something goes mysteriously wrong with the shuttle, we could lose LIVES! The manned space program is intentionally safety conscious. They don't want any surprises. Thus they stick with what they know has worked in the past. If they wanted to completely change around the GPCs, using the most up-to-date technology that they think would work in orbit (an important consideration, by the way), they would have to start the orbiter's testing process all over again: drop it from a 727, have an initial test flight with two test pilots and with ejection seats, etc., etc., etc. By the time they were convinced that everything worked smoothly, the technology would be woefully out of date. Also, something people seem to have forgotten: the GPCs are redundant. They have to talk to each other to carry out this redundancy. There's some non-trivial hardware in there to make that happen. You just can't do that with 5 IBM PC clones clamped on an ethernet. This goes far beyond the computers themselves. All of that would have to be scrapped and redone as well. Why did they choose the 101-B in the first place? Because they knew that it worked in fighters when they first started designing this stuff. |> That, though, is the ultimate state of any hidebound bureaucracy: it's |> better not to make a mistake than not to accomplish anything. No, that is the ultimate state of anything that deals with human lives: it's better to be safe and alive than to be cutting-edge and dead. William LeFebvre Computing Facilities Manager and Analyst Department of Electrical Engineering and Computer Science Northwestern University <phil@eecs.nwu.edu>
rose@beowulf.ucsd.edu (Dan Rose) (03/12/91)
dil@mace.cc.purdue.edu (Perry G Ramsey) writes: >... The state of the Shuttle GPC >indicates pretty clearly that the current >NASA (at least the manned space side) is scared to death of anything new. >That, though, is the ultimate state of any hidebound bureaucracy: it's >better not to make a mistake than not to accomplish anything. Hmm, does NASA think Apollo 11 would have made it to the moon if it had been carrying those WWII-era differential analyzers used to compute ballistic trajectories? -- Dan Rose drose@ucsd.edu
henry@zoo.toronto.edu (Henry Spencer) (03/12/91)
In article <1991Mar7.142311.10412@vaxa.strath.ac.uk> cabp10@vaxa.strath.ac.uk (Theora Jones, In Person!) writes: >... I would expect radiation hardened processors, of an industry sstandard >type (80x86, or 680x0 series) for easy replacement... Do remember that this hardware was designed in the mid-70s; the processors you mention did not exist then. And I'm not sure what you mean by "easy replacement", given that rad-hardened processors are usually single-source items even if the architecture is in wide use. (There *is* one significant advantage of using something standardized: the ability to use commercial hardware for development.) In general, it's clear that the computers would look very different if they were being designed today and the software was being rewritten from scratch. Those conditions do not apply. >... if in 1991, the leading manufacturers of semiconductors can >put upwards of 10^6 transistors on a chip, but can't make radiation resistant >store... Rad-hardening is a very specialized business that is not likely to attract manufacturers who specialize in mass production of commodity parts. DRAMs are the ultimate in mass-produced commodity parts. -- "But this *is* the simplified version | Henry Spencer @ U of Toronto Zoology for the general public." -S. Harris | henry@zoo.toronto.edu utzoo!henry
henry@zoo.toronto.edu (Henry Spencer) (03/12/91)
In article <1991Mar11.201910.8476@casbah.acns.nwu.edu> phil@eecs.nwu.edu (William LeFebvre) writes: >If you want to see NEW technology being used at NASA, check out the >UNmanned projects. They aren't afraid to use new technology. Why? >because the worst that can happen is we lose an expensive piece of >equipment... Uh, I hate to burst your bubble :-), but the unmanned projects also avoid new technology like the plague. Losing that "expensive piece of equipment" can mean waiting *decades* for another chance to fly your experiment to its chosen destination. There is enormous pressure to use off-the-shelf technology even when new technology would greatly benefit the mission. This is why the unmanned missions are still using 1965-vintage propulsion systems. They only recently started using solid-state image sensors rather than image tubes, and *that* happened mostly because JPL's preferred tubes were out of production and unobtainable! The only time people aren't afraid to use new technology is when they can lose a mission without serious damage to careers or funding. The days when that was true in (most of) NASA are long gone. The Explorer-series people can maybe risk it, since they've got steady funding for an ongoing series of missions. The planetary people certainly can't. -- "But this *is* the simplified version | Henry Spencer @ U of Toronto Zoology for the general public." -S. Harris | henry@zoo.toronto.edu utzoo!henry
stanley@phoenix.com (John Stanley) (03/14/91)
rnm8s@helga4.acc.Virginia.EDU (Rory Neil Mcleod) writes: Newton: For every action there is an equal and opposite reaction. > Bureacracy tends to slow the rate at which changes are made, > but, the STS is a huge system, what may seem like a little > change to one system may have a major impact someplace else. > The checks and balances are there for a reason. News story: The introduction of high capacity hard disks in the latest shuttle mission has had a strange reaction. STS-99 has run out of maneuvering thruster fuel and is now spinning. It seems that the force applied to spin the disks has followed Newton's laws, and the shuttle is now also spinning - the opposite direction. Since the programs on the disks are required for landing, they cannot be spun down until after landing, and the shuttle cannot land until the disks are spun down. The shuttle astronauts are taking emergency dancing lessons (mostly the "twist"), but whether this will help will not be known for several hours. Mandatory :-).
petej@phred.UUCP (Peter Jarvis) (03/18/91)
In article <1991Mar12.003321.13988@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: > > There is enormous pressure to use off-the-shelf >technology even when new technology would greatly benefit the mission. >This is why the unmanned missions are still using 1965-vintage propulsion >systems. > Note the relatively new Boeing IUS. (The first one failed, but they're working fine now). Peter Jarvis...........
henry@zoo.toronto.edu (Henry Spencer) (03/20/91)
In article <3356@phred.UUCP> petej@phred.UUCP (Peter Jarvis) writes: >> There is enormous pressure to use off-the-shelf >>technology even when new technology would greatly benefit the mission. >>This is why the unmanned missions are still using 1965-vintage propulsion >>systems. > >Note the relatively new Boeing IUS... I note it. I also note that something very much like it could have been built in 1965. The electronics would have been clunkier, the performance would have been a bit lower due to heavier casings, and they might not have been able to do the telescoping nozzles, but there's hardly any fundamentally new technology in the IUS. It's a very ordinary two-stage solid rocket. -- "[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry
petej@phred.UUCP (Peter Jarvis) (03/21/91)
In article <1991Mar19.235853.6842@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: > >..... but there's hardly any >fundamentally new technology in the IUS. It's a very ordinary two-stage >solid rocket. Well what would you have designers put into a solid rocket booster besides stronger, lighter (composites) casings and new electronics? Those items are not trivial. The fuel? They've probably optimized solid rocket propellant to burn the way they like it. What else are you looking for in a solid rocket motor? -- P.J.
henry@zoo.toronto.edu (Henry Spencer) (03/22/91)
In article <3361@phred.UUCP> petej@phred.UUCP (Peter Jarvis) writes: >Well what would you have designers put into a solid rocket booster >besides stronger, lighter (composites) casings and new electronics? >Those items are not trivial. The fuel? They've probably optimized solid >rocket propellant to burn the way they like it. What else are you looking >for in a solid rocket motor? -- P.J. What I'm looking for ON a solid rocket motor is dust, plus a museum placard saying "obsolete form of space propulsion system, abandoned in the early 1970s when ion rockets became practical". We've known for twenty years how to build rocket systems that perform far better than any solid rocket motor ever will. Bad enough that we are still launching comsats with them, but it is a disgrace to NASA and mankind that we are still using them for deep-space probes that are desperate for every bit of launch performance. -- "[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry