Space shuttle for space tourism and first stage of a TSTO.
in [Physics]
|
Prev: Eclipses Yield First Images of Elusive Iron Line in Solar Corona
Next: What happens when all dimensions are doubled overnight?
From: Peter Stickney on 16 Jan 2010 20:43 Pat Flannery wrote: > David Spain wrote: >> Pat Flannery <flanner(a)daktel.com> writes: >> >>> take-off trolley, with a trained Chimpanzee in the cockpit...but not >>> just any Chimpanzee...a Chimpanzee that has been genetically modified >>> with Bald Eagle DNA to give it an intuitive ability to understand >>> flight... ;-) >> >> Is that Chimpanzee over-caffinated too? > > Nothing that banal; the Eagle/Chimp hybrid (Eaglepanzee) will be given > Ayahuasca by an Amazonian shaman to allow it to pilot the vehicle > without even looking out the windows - by causing its spirit to be > everywhere at once, and in the past, present, and future simultaneously, > like a furry little Guild Steersman. Erm, Pat - The Business Folks all think it's Way Shiny (Especially since there's Magic involved), but the Marketing Ferrets say that the name doesn't fly. They're suggesting Chimpanzeagle as an alternative. (And I'm bidding on the Lancelot Link Trainer for the workup facility) -- Pete Stickney Failure is not an option It comes bundled with the system.
From: Robert Clark on 19 Jan 2010 17:56 On Jan 5, 10:26 am, Robert Clark <rgregorycl...(a)yahoo.com> wrote: > ... >The Air Force is looking for designs for reusable first stage boosters for two-stage-to-orbit >(TSTO) systems. Then it might be able to be used for this purpose. Most likely you would use >kerosene fuel for this since dense fuels are more suitable for first stages. >The payload bay would be converted to a fuel tank, and the second stage of the TSTO would >be carried on top or below the orbiter. High performance kerosene engines such as the >Russian NK-33, with a near legendary thrust/weight ratio of 136.66 to 1 at a weight of 1,222 >kg, could be used for propulsion: >NK-33. >http://www.astronautix.com/engines/nk33.htm >The orbiter without the SSME engines masses around 68,600 kg: >Atlantis. >http://www.astronautix.com/craft/atlantis.htm >Its payload bay is around 300 cubic meters that could be used for propellant. Using the >densities of kerosene and lox given here: >Lox/Kerosene. >http://www.astronautix.com/props/loxosene.htm >and the oxidizer to fuel ratio of the NK-33 of 2.8 to 1 we can calculate the propellant load that >can be carried as about 300,000 kg. You would need at least 3 of the NK-33's to lift this fuel >load, orbiter and second stage. >The tank weight of kerosene/lox is typically around 1/100th of the propellant weight so around, >3,000 kg. Then the empty weight of the reconfigured orbiter would be 68,600kg + 3*1,222kg + >3,000kg = 75,266kg. And the fully fueled weight of this stage would be 375,266kg. I mentioned before converting the space shuttle orbiter into a first stage use would actually be quite important. I discuss this below. I.)Weight savings by removing unneeded components. II.)Replacement of the Ares I first stage by the reconfigured shuttle. III.)Costs saving by private commercial financing rather than "cost- plus" contracts. I.) I wanted to get some shuttle component weights to estimate the weight savings we could make by removing systems that would not be needed for a suborbital or first stage use. The Astronautix page on the Shuttle Atlantis gives its "Heat Shield Mass" as 12,100 kg (26,600 lb). However, Astronautix is sometimes inaccurate. So I found this report after a web search: Thermal Protection System Sizing and Selection for RLVs Using the Sentry Code. http://www.sei.aero/eng/papers/uploads/archive/AIAA-2006-4605.pdf It gives on page p. 11 a weight of 17,910 lbs for the thermal protection tiles and panels but notes other hardware for the TPS amounts to 4,600 lbs. for a total of 22,510 lbs., 10,232 kg. I'll use this value for the shuttle TPS. I've been informed by someone who did a study for the Air Force's "Reusable Booster System" program that for first stage use at low hypersonic speeds an aluminum frame would require minimal thermal protection. See the slides from pages 5 and 7 of this report on the Air Force's RBS program: Spacelift Development Plan. http://www.acq.osd.mil/nsso/conference/briefs/HampstenSDP%20Public%20Release.ppt So I'll subtract off the 10,232 kg TPS weight from the 75,266 kg dry weight I got for a reconfigured orbiter, to get a 65,034 kg dry weight. This NASA page says a saved weight of 450 lbs off the OMS system amounted to 10% of its weight: OMS/RCS PODS. http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_coord.html#sts_oms_pods So I'll remove the OMS system to save 4500 lbs, 2,000 kg, bringing the dry weight now to 63,035 kg. This page gives the left payload bay door weight as 2,375 lbs. and the right as 2,535 lbs., and both doors containing radiator systems at an additional weight of 833 lbs each: PAYLOAD BAY DOORS. http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/stsref-toc.html#payload_bay_doors These won't be needed so removing these would save 6,576 lbs, 2,990 kg, bringing the dry weight to 60,000 kg. The Buran showed it's possible for the shuttle to have a completely automated ascent and descent, so I'll remove the life support components from the mass to use the orbiter as an unmanned first stage. For lack of any other reference on the mass of these components I'll subtract off the numbers given on the Astronautix Atlantis page of "Crew Seats and Provisions" as 750 kg and "Environmental Control System" as 2,500 kg, for a total saving of 3,250 kg, bringing the dry weight to 56,750 kg. Probably the fuel cells and the tanks to hold the on board LOX and LH2 for the fuel cells could be removed, since as a first stage its flight would only last minutes rather than the days of a manned orbiter flight. For such short flights, lightweight batteries or electrical generators powered by the engines would suffice. This page gives the fuel cell's oxygen tank weight as 201 lbs. and the hydrogen tank weight as 216, and says there are a maximum of 5 pairs of tanks: POWER REACTANT STORAGE AND DISTRIBUTION. http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-eps.html#sts-eps-prsd I'll take the total fuel cell's tank weight as 2,085 lbs, 948 kg. There are three fuel cells each weighing about 120 kg, for a total of 360 kg. So I'll subtract off 1,308 kg from the dry weight to bring it to 55,442 kg. II.) The manned space program is in a quandary now because of the ballooning costs overruns on the Ares I system that was supposed to act as the next manned transportation system. The primary difficulty was the Ares I first stage boosters. Originally the development cost was set at $1.8 billion dollars, though fixes to for example the excessive vibration generated undoubtedly has increased that cost: Aug. 10, 2007 NASA Awards First Stage Contract for Ares Rockets. "WASHINGTON - NASA has signed a $1.8 billion contract with Alliant Techsystems, known as ATK, located near Brigham City, Utah, for the design, development, testing, and evaluation of the first stage of the Ares I and Ares V launch vehicles." http://www.nasa.gov/home/hqnews/2007/aug/HQ_C07036_Ares_first_stage.html Moreover, weight growth and a short fall in the delta-V delivered by this first stage drove costly adjustments of the upper stage as well. My point is adapting the shuttle or the Buran for first stage use would vastly reduce the cost for a first stage. You would have then several options for manned flight all of which would be cheaper than using the Ares I first stage solid motors and all of which would allow a return to space at a faster time scale than the original Ares I plan. I'll give a calculation that you could still carry the planned upper stage and payload of the Ares I with the reconfigured shuttle as first stage. This page gives the specifications of the Ares I: Space Launch Report - Ares I. http://www.spacelaunchreport.com/ares1.html The gross weight including payload is given as 912,660 kg and the gross weight of the first stage as 732,550 kg. So the gross weight of the Ares I second stage plus payload is 180,110 kg. Then the gross weight for the 55,442 kg dry weight of the reconfigured shuttle, plus 300,000 kg propellant load, plus 180,110 kg second stage and payload is 535,552 kg, 1,178,214 lbs. But the 3 NK-33 engines I was suggesting to use only put out a total of 1,018,518 lbs. of thrust at sea level. For this purpose you would need a fourth NK-33. The dry weight is now 56,664, the gross weight is 536,774 kg, 1,180,903 lbs., and the sea level thrust of the 4 engines is 1,358,024 lbs. Using the average Isp of the NK-33 as the midpoint of the sea level and vacuum Isp's at 315 s, the achieved delta-V would be 315*9.8*ln (536,774/(56,664+180,110)) = 2,527 m/s, comparable to the equivalent delta-V, speed + altitude, provided by the Ares I first stage. The achieved delta-V is actually higher than this since the rocket spends most of the time at high altitude, where the Isp is closer to the vacuum value. Note that if you want to increase the delta-V, the space occupied by the crew compartment is now empty. This gives an additional 74 cubic meters that could be used for propellant, which amounts to 74,000 kg additional lox/kerosene propellant that could be carried. Then we could still use the planned upper stage of the Ares I while having a significantly lower development cost and per launch cost of the now reusable first stage. Still the time when we could reach flight status would be dependent on the development of the upper stage. However, we don't need to use the large Ares I upper stage and Orion capsule if we just want manned flight. I'll show in a following post we could get a smaller and reusable manned upper stage at a much lower cost also than the Ares I upper stage and Orion capsule, that will also allow a much quicker return to manned flight. III.) I wish also to argue however that for these methods, for the reconfigured shuttle/Buran first stage and smaller reusable manned upper stage, we don't want to use the standard procurement methods with the "Old Space" aerospace companies. Robert Zubrin has some insightful observations about the "cost-plus" government contracts that the large aerospace companies get in his book, [u]Entering Space: Creating a Spacefaring Civilization[/u]. In the chapter, "The Age of the Dinosaurs" referring to the "Old Space" companies, he first comments that high launch costs drive the tendency to make satellites be highly reliable which drives the cost for the satellite higher. And conversely if your satellite is already very expensive, say a $1 billion Air Force satellite, then there is little incentive to reduce launch costs since at that satellite price a launch cost of $100 million or zero makes little difference. Then Zubrin says: "Beyond these considerations stands the government contracting system known as "cost plus," which has been in place for some time now in the United States. According to the people who invented this system, it is essential that corporations be prevented from earning excessive profits on government contracts. Therefore, rather than negotiate a fixed price for a piece of hardware and allow the company to make a large profit or loss on the job depending on what its internal costs might be, regulators have demanded that the company document its internal costs in detail and then be allowed to charge a small fixed percentage fee (generally in the 10 percent range) above those costs as profit. This system has served to multiply the costs of government contracting tremendously, so much so that it has produced public scandals when news leaks out about the military paying $700 for a hammer or a toilet seat cover." [u]Entering Space[/u], by Robert Zubrin, p. 24. Then I'm suggesting that the "New Space" companies rather than going through the usual "cost-plus" financing from the government could purchase a shuttle/Buran on their own and develop the manned reusable upper stage on their own with the idea of making a profit. I'm arguing the development cost of this reconfigured first stage and the small upper stage would be so low that this can be profitable both for satellite launch and for now fully orbital space tourism. Bob Clark
From: Pat Flannery on 20 Jan 2010 01:26 Me wrote: > When a person of educational > responsibility goes unchecked and spreads ideas that are contrary to > physics and excepted engineering standards, there should be some > course of action to bring this to the attention of his employers You get the pointy hat, I'll get the fake wart. Then we'll send them a photo of him sitting on a pair of scales, showing that he obviously weighs the same as a duck. Then they will surely burn him. ;-) Pat
From: Pat Flannery on 20 Jan 2010 01:29 Jorge R. Frank wrote: > > Just so you know, for those of us who already have Clark killfiled, > these responses without quoting the original don't really add anything > since we don't see the k00kspew you're responding to. > > Not that that's *necessarily* a bad thing, mind you... A large toad would add to the "sure witch" evidence also. ;-) Pat
From: Robert Clark on 20 Jan 2010 11:07
On Jan 5, 10:26 am, Robert Clark <rgregorycl...(a)yahoo.com> wrote: > This article describes the plan to sell the orbiters minus engines > for $42 million: > > For sale: Used space shuttles. Asking price: $42 million apiece > By John Matson > Dec 18, 2008 04:00 PM in Spacehttp://www.scientificamerican.com/blog/post..cfm?id=for-sale-used-spac... > > It is currently intended only to be sold to educational institutions, > or governmental agencies. > The Air Force is looking for designs for reusable first stage > boosters for two-stage-to-orbit (TSTO) systems. Then it might be able > to be used for this purpose. Most likely you would use kerosene fuel > for this since dense fuels are more suitable for first stages. > ... Deep Discount on Space Shuttles. By THE ASSOCIATED PRESS Published: January 16, 2010 "CAPE CANAVERAL, Fla. (AP) Here is a recession bargain: the space shuttle. NASA has slashed the price of the 1970s-era spaceships to $28.8 million apiece from $42 million." http://www.nytimes.com/2010/01/17/science/space/17nasa.html What I found really interesting was this passage: "As for the space shuttle main engines, those are now free. NASA advertised them in December 2008 for $400,000 to $800,000 each, but no one expressed interest. So now the engines are available, along with other shuttle artifacts, for the cost of transportation and handling. "Assembly will be required, however." I doubt though you could keep these engines and be profitable as a suborbital tourism vehicle or first stage booster. The maintenance costs on these engines are just so high. However, the most maintenance intensive parts were the turbopumps for the high pressure cryogenic LOX and liquid hydrogen. If you could switch out these turbopumps to lower performance dense propellant ones, or find some other method rather then the original turbopumps for pumping the LOX/LH2 at these volumes and high pressures it might be doable. Bob Clark |