Hello All,

Below are links to material on several MCD (Minimum Cost Design) launch vehicles, which are designed to be as simple and cheap to produce in quantity as possible without sacrificing reliability. Their design philosophy intentionally ignores the "Better" (meaning technologically advanced and highly efficient) part of the "Better, faster, cheaper" maxim and concentrates on the other two, primarily the "cheaper" part.

Lt. Col. John R. London III's report titled "LEO on the Cheap: Methods for Achieving Drastic Reductions In Space Launch Costs" (see: http://www.dunnspace.com/leo_on_the_cheap.htm ) contains drawings of numerous MCD launch vehicle designs and historical information on them. One design in particular (which has actually been flight-tested suborbitally) is the Scorpius (see: http://www.smad.com/ie/ieframessr2.html and http://www.scorpius.com/ ), a simple, pressure-fed LOX/Jet-A (jet fuel) powered vehicle that can be flown by itself as a sounding rocket or clustered to form a parallel-staged satellite launch vehicle that is similar in concept to Interorbital Systems' Neptune series of modular satellite launch vehicles (see: www.interorbital.com ).

I hope this material will be useful.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

I went to their shop when Scorpius was being built and saw several of the ground tests. I was not there for the flight test as it was on a military range. I have however touched the post-flight variant of the vehicle several times in the lobby of their facility. They have a large facility which remains in operation. They fabricate CF tanks for high pressure applications and are capable of making very low mass tanks for low pressure applications. One of their newest style tanks was used on the successful winning entry to the Lunar Lander Challenge.

They have an ongoing arrangement with the Air Force to work on cost saving products that would eventually result in an actual low cost launch vehicle. They are in actual commerce.

Jerry

I just noticed that today is the 10th anniversary of the launch of their 42" diameter test vehicle (they also flew an 18" diameter proof-of-concept vehicle/small sounding rocket in 1999). I too am gratified to see that they are actually selling products that they manufacture--when you have both accounts receivable *and* accounts payable, you're really in business! I think their filament-wound composite propellant tanks *and* engines could even have potential (if scaled down) in model rocketry and HPR--I'd love to see them make a hobbyist-size propane/nitrous oxide system. Being almost totally non-metallic, their designs certainly adhere to the NAR Safety Code.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

A couple of their employees are rocketeers, but they have no interest in small rockets I assure you. I am on that customer list. They do not charge low prices.

Jerry

What benefit would this technology have compared to our usual BP or APCP motors? Interest in hybrid motors seem to have sublimated since the winning of the lawsuit.


Bill

Scale realism is one factor (and a big one). Just as many R/C model jet enthusiasts are willing to pay more to have real miniature turbojet engines in their models even though glow engine and electric ducted fans cost much less, many model rocketeers (myself included) would pay more to have an honest-to-goodness liquid propellant rocket engine system to power scale models of liquid propellant rockets and missiles.

R/C jets have the authentic turbojet startup & idling whine, full-thrust roar, and exhaust appearance of full-size jet engines, and a liquid propellant rocket would have a true-scale exhaust flame size, flame appearance, and roar, as well as (if desired) a longer, more realistic burn time. By varying the fuel/oxidizer (propane/nitrous oxide) mixture ratio, a bright yellow flame like that of a LOX/kerosene rocket engine could be produced (like the bright yellow flames of the propane "whisper burners" used in hot air balloons to avoid spooking cattle). A transparent reddish flame or white flame (depending on the mixture ratio) with shock diamonds (like those of hypergolic propellant missiles such as the Lance and the Titan II) could also be produced for scale realism in scale model rockets.

Another attractive feature of a liquid propellant rocket system is that unlike a hybrid, it allows the user to load as much (up to the maximum tank capacities) or as little of both the fuel and oxidizer as desired, in order to tailor the burn duration and maximum altitude to the size of the flying field and/or the local wind conditions.

Also, using a simple pintle injector would enable the engine to be throttled, which would make it feasible to program the thrust-time curve to provide high thrust at launch and a lower sustaining thrust afterwards. This would allow long, satisfying engine burn times without having the model fly so high that it would touch down in the next county. Alternatively, choosing a relatively low thrust level for launch would permit slow, realistic liftoffs and acceleration phases for scale models of large liquid propellant rockets and ballistic missiles.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

It is very attractive the way you describe it. I cannot see NAR ever agreeing to certify that; maybe TRA experimental?


Bill

Thank you. There are ways around NAR objections. For example, a safe tridyne propellant combination (which NASA considers safe enough to be used in the interiors of human-habitable enclosed spaces in outer space) could be used. A tridyne propellant combination consists of dilute amounts of fuel and oxidizer mixed with an inert buffer gas such as nitrogen or helium, and the fuel and oxidizer in the tridyne mixture cannot be ignited except in the presence of a catalyst. Below is more information on tridyne propellants (copied from here: http://en.wikipedia.org/wiki/Talk%3ARocket_propellant [the text on the web page contains additional links to further information]):

Tridyne, or Nitro-dyne, rocket fuel--Might want to add to the article something about a rocket fuel that is considered safe for being in the interior of human-habitable enclosed spaces in outer space: Tridyne, or Nitro-dyne. I was unsuccessful in finding anything about it on Wikipedia.

Both this NASA source (on pp 18 of 23, NASA JSC Presentation: Human Spaceflight Affordability: Advanced In-house Development Portfolio January 2011) and this blog post by Jon Goff (ISS Micro-Return Vehicle Concept, January 2011) discuss the fuel and the small rocket propulsive systems that might use it. Goff calls it

"a non-toxic propulsion system. Both JSC and Altius came to the same solution of using a Tridyne (well technically Nitro-dyne) warm-gas system. “'Tridyne'” is a gaseous mixture of dilute amounts of hydrogen and oxygen in a suitable buffer gas (Helium or Nitrogen). The idea is the hydrogen and oxygen are at such low concentrations that the mixture is not flammable in air, and the two components cannot ignite due to the buffer gas, except in the presence of a suitable catalyst. The resulting “flame” is cooler than even a H2O2 monopropellant thruster, with corresponding worse performance–somewhere in the 120-140s vacuum Isp. While you wouldn’t want to use this for a high-delta-V mission due to poor achievable propellant tank to propellant mass ratios and low Isp, it is probably adequate for the small station departure and deorbit burns (100-150m/s according to the presentation). The complexity of the system ends up being even less than a hydrazine monopropellant system (no need for heaters, pressurization systems, etc) and avoids toxicity issues."

NASA says only a few words about the propulsion part of their "ISS Return Capsule":

"Propulsive System: Facilitates safe operation inside pressurized vehicles, departure from the ISS, re-entry insertion, and landing at a specified landing location. Will be pressurized cold gas shystem. Current leading candidate is Tridyne."

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR