A kerosene-fueled X-33 as a single stage to orbit vehicle.
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From: Rick Jones on 29 Mar 2010 20:52 In sci.space.history Pat Flannery <flanner(a)daktel.com> wrote: > On 3/29/2010 2:40 PM, Rick Jones wrote: > > Sure - it comes in a plain, white container, with no markings except > > "Satellite" on the outside in plain block letters printed in black. :) > > > > http://en.wikipedia.org/wiki/Generic_brand > I still like the alcoholic beverage "Drink" out of Repo Man. Is that still in the remake? rick jones -- I don't interest myself in "why". I think more often in terms of "when", sometimes "where"; always "how much." - Joubert these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
From: Marvin the Martian on 29 Mar 2010 21:34 On Mon, 29 Mar 2010 09:46:55 -0700, Robert Clark wrote: > Single Stage To Orbit Mass Budgets Derived From Propellant Density and > Specific Impulse. > John C. Whitehead, Lawrence Livermore National Laboratory. 32nd > AIAA/ASME/SAE/ASEE Joint Propulsion Conference. Lake Buena Vista, FL > July 1-3, 1996 > http://www.osti.gov/bridge/servlets/purl/379977-2LwFyZ/ webviewable/379977.pdf This paper is absurd. He even admits that his calculations presume a non- reusable, fragile SSTO, and that is pointless, as there is NO POINT in NOT staging if you're going to expend the entire vehicle ANYWAY. He points out that to make any sense, you need a robust thus more massive structure but he understates the case as he omits that you also need a re- entry mechanism like a heat shield. Other papers have pointed out that RP-1 may be a better fuel because there is less required structure, no cryogenic pumps, and no insulation; and all that would otherwise be payload. But it does not follow that SSTO is possible by using a LOWER I_sp fuel, as I pointed out. The physics just doesn't allow it. Not on Earth. It can be done on my home planet, Mars, but not here. The author, apparently unfamiliar with logic, claims that "it is logical to first develop (SSTO and re usability) independently". No it is not logical, that doesn't follow at all. Like I said, it may be that denser, non-cryogenic fuels result in larger payload mass, but lower I_sp does NOT enable SSTO.
From: Pat Flannery on 30 Mar 2010 03:52 On 3/29/2010 6:30 AM, Jeff Findley wrote: >> >> As if "short notice" is an issue since satellite planning usually takes >> years anyway. > > This is a really dumb statement. > > If you're cranking out multiple copies of something like a spysat with a > film return reentry vehicle, having the ability to quickly launch one into a > particular orbit is a good thing. Other sorts of military satellites could > have similar missions, at least as far as launches and orbits are concerned. It was to get away from the concept of the super-capable spy satellites (which cost a fortune to build, and are therefore budget-limited in number that can be built) that the military is showing more interest in smaller, lighter, and cheaper reconsats that can be built and stored for launching if a situation develops where image intelligence is needed of a particular area on fairly short notice, even if it isn't of the resolution something like a KH-12 could deliver. I think that the French SPOT satellite images gave them a kick in the right direction in this regard: http://en.wikipedia.org/wiki/SPOT_%28satellites%29 It will be interesting to see if the X-37B turns out to be a reusable reconsat system, as I suspect it might be. If you can get all the imaging equipment back at the end of each mission, you can afford to spend a lot on it. Although our Corona satellites were quite economical to launch on their Thor boosters, you lost the whole camera system on each mission. The Soviet equivalent, Zenit, let the camera system be recovered for reuse, although the Vostok boosters they went up on probably cost more than our Thor-Agenas. Pat
From: Pat Flannery on 30 Mar 2010 04:20 On 3/29/2010 4:23 PM, Greg D. Moore (Strider) wrote: > Funny this comes up as this month's issue of Air& Space has an article: > http://www.airspacemag.com/space-exploration/Mr-Fix-It.html on Frank > Cepollina who sort of proposed a "generic satellite bus". The idea goes way back; the Ranger Moon probes and early Mariner spacecraft were pretty similar in a lot of their basic systems and design layout. Also IIRC, the later Explorer series used pretty much the same spacecraft bus with all sorts of different experiments attached to it. Pat
From: Pat Flannery on 30 Mar 2010 04:26
>> I still like the alcoholic beverage "Drink" out of Repo Man. > > Is that still in the remake? If they do it, they will probably change the title, as it's been re-used for the artificial organ reclaimers movie. It would be hard to improve on the quirkiness of the original, especially the "John Wayne in a dress" and "don't look in the trunk" parts. Pat |