szabonj@ibmpa.UUCP (Nick Szabo) (12/20/89)
In article <1989Dec19.001442.18701@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <3332@ibmpa.UUCP> szabonj@ibmpa.UUCP (Nick Szabo) writes: >>Unmanned strikes again! Delta launches cost probably one-fifth to >>one-tenth of a Shuttle launch, depending on whose accounting you want >>to believe. > >I believe the NRC's accounting, which says that all current US launchers >cost about the same per pound at the same launch volume. The enormous >cost advantage of unmanned launchers is a myth. > >Well, one caveat: Delta probably *is* somewhat cheaper now because those >are (I think) commercial launches rather than government-run ones; that >development is more recent than the NRC findings. Of course, I was talking about absolute cost, not cost per pound. Delta launch versus Shuttle launch, is what I said. "Cost per pound" is not necessarily a good measure; we should think in terms of "cost per useful payload." The second ton is usually not as valuable as the first ton, and the third is not as valuable as the second, etc. You often can't cram twice as much into twice the mass, because "the second box never fits as nicely as the first." In fact, bulk and shape of the payload are often more important than mass. That is why Earth's major cargo carriers now use the standard truck-trailer-sized "container" for rail, truck, ocean, and even sometimes air freight. Hopefully, we will soon have a set of standards for space cargo. In fact, I can foresee somebody like AMROC making a "Delta clone": a launch vehicle with the same exact cargo hold as the Delta, with the same lift capability, but using the new AMROC engine technology. That way, satellite makers can design their satellites for the standard without have to commit to any specific launch vehicle. Also, implementers of new technologies like EML or laser-launch would be well-advised to scale the machines to existing payloads. ******** These opinions are not related to Big Blue's ********* -- --------------------------- Nick Szabo szabonj@ibmpa.tcspa.ibm.com uunet!ibmsupt!szabonj
henry@utzoo.uucp (Henry Spencer) (12/21/89)
In article <3354@ibmpa.UUCP> szabonj@ibmpa.UUCP (Nick Szabo) writes: >Hopefully, we will soon have a set of standards for space cargo... Actually, we already have this in small ways. Commercial Titan payload fairings are the same as Ariane 4 payload fairings (MM buys them from the same outfit -- I think it's Contraves in Switzerland -- that builds them for Ariane). However, the real problem is that there is no standardization *within* a single launcher's payloads, never mind across launchers. Every launch is a custom job at present. If you read the user's manual for a launcher (I've seen the ones for Ariane and Titan), you find not a standard set of services and facilities, but a list of constraints on exactly what custom facilities can be provided. I suspect that this situation is likely to continue as long as launch volumes are low. The ALS people have talked about various schemes for both standardizing interfaces and minimizing them (requiring payloads to be more independent of the launcher), but ALS is most unlikely to ever become real, precisely because there isn't enough volume of business to justify it. >... Also, implementers of new technologies like >EML or laser-launch would be well-advised to scale the machines to >existing payloads. I think we can be fairly sure that that *won't* happen. Many of the non-rocket schemes really want to work with much smaller payloads; the costs scale non-linearly with payload size. For example, existing CO2 laser technology would probably suffice for a laser launcher... if the payload is measured in tens of kilograms, not thousands. Such systems have enormous capacities, but they get them by launching lots of small payloads, not a handful of big ones. What's more, such systems will be justified in terms of launching new kinds of payloads, not existing ones. -- 1972: Saturn V #15 flight-ready| Henry Spencer at U of Toronto Zoology 1989: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu