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Reusable Launch & Space Vehicle News
February 2003 - Feedback

Armadillo X Prize Vehicel
Copyright of Armadillo Aerospace

An artist's composite rendering of Armadillo Aerospace 's X Prize
vehicle under development.(Large Image
)


Other RLV News Sources
Space Frontier Society * Space Access Society Updates *
NASA SLI News * NASA SpaceTransportation *
NASA Watch Launch System News * OrbiReport - Space Transportation News *
Spacetoday.net (Jeff Foust): Launch Vehicles

This section contains brief articles concerning developments in the field of reusable launch and space vehicles with links to news sources, NASA, company sites, etc.

See the Space Log for entries
on related topics such as amateur rocketry, space businesses, etc.

RLV News Archive Directory


February 15, 2003

Marcus Lindroos is a long time observer and commentator on space history, RLVs and other space topics. We exchanged some emails recently and here are some remarks he made on the OSP:

My "pet concept" right now would be an air-launched Orbital Space Plane! It appears to be a workable "third way"; not as difficult or expensive to develop as a fully reusable spaceplane but still cheaper to operate since only the big external tank is not reusable. Yes -- people were saying the same thing about the Space Shuttle. However, this concept would be 100% focused on rapid-access crew transfer and resupply. It would not be a huge multimission platform, it would not require a vast launch pad infrastructure at KSC and the launch safety and flexibility options would be much better (horizontal launch vs. SRBs).
---
The USAF proposed a Boeing 747 based small spaceplane design in 1979 [ http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld053.htm ] and the Russians have recently revived the concept ("MAKS" -- http://www.buran.ru/htm/molniya.htm ). In 1993, British Aerospace estimated MAKS would be cheaper by a factor of ten than Ariane-5/Hermes. This means the cost per seat would fall from ~$30 million for the Delta IV OSP to about $3 million. I think we would see more Dennis Titos and Mark Shuttleworths, and it would be easier to move commercial experiments to ISS as well.

Yes an air-launched OSP sounds reasonable. However, the "OSP on an ELV" is becoming the only tune heard within the Beltway e.g. http://www.nytimes.com/2003/02/11/science/space/11OTHE.html so I'm afraid there won't be any real discussion to alternative approaches.

< groan... > Winged vehicles and ELVs just don't mix very well. DynaSoar, Hermes and the rest all encountered problems with weight growth, crew safety and LV/mini-shuttle aerodynamic integration. A winged vehicle will invariably be heavier than a capsule, and the wing area must be kept to a minimum or else bending loads on the booster will become a major problem. The end result is that many key subsystems will have to be moved to an expendable "orbital module" which is jettisoned before reentry so that the vehicle is light enough to glide back to a landing airfield. The weight problem will only get worse when NASA tries to come up with a realistic crew escape system...

ELVs are dangerous and unreliable during ascent to orbit. The only good solution (an escape tower+separate crew capsule) won't work for weight reasons, and ejection seats will not be good enough. Standard fighter aircraft seats only work below Mach 2 or so and they will not move the crew sufficiently far away fr! om an exploding rocket. More powerful high-altitude seats will kill the astronaut unless the seat is encapsulated, XB70 Valkyrie-style. The Hermes engineers tried all kinds of approaches before settling for ejection seats; this limited the number of crewmembers to three per flight for weight and volume reasons. And they were going to pay 130 million Euro for that.

http://www.abo.fi/~mlindroo/armagddn/iaf94h2778.pdf

If NASA *must* have an EELV-launched crew transfer vehicle, it should develop a capsule instead... ESA estimated that an 8-man CTV capsule could be developed for about $2 billion vs. $5.5B+ for Hermes. Unfortunately, Europe had already wasted $2 billion on Hermes by this time!

February 5, 2003

Dave Ketchledge, who has extensively studied re-entry systems and lifting body designs, discussees thermal protection issues and responds to my entry "Ten Years and $35 Billion? :

I am Dave Ketchledge a senior member of both Tripoli an the NAR who worked in guided model rocketry and other major topics in the 1990s's In 1988 I released to CompuServe my 600 page work called "Microshuttle" for a lear jet sized space plane. North American Rockwell, Boeing and the Navy were favorably impressed with the effort. In 1997 I was a keynote speaker to University of Illinois school of Aerospace Engineering on the topic of rocketry education and Flight Mechanics. Currently I am working on aerodynamics analysis on lifting bodies like the X-33, X-38 for an upcoming publication planned well before this tragic event.

In my Microshuttle work I spent a chapter on the subject of aerothermodynamics stating that the Ceramic tile system on the Shuttle was
poorly bonded to the vehicle and was time consuming to keep in operation. My suggestion which I own a copyright on is a foaminated boron silicate glass with a pyrolized graphite skin panel. While heavier than a shuttle tile, the graphite/glass matrix offered outstanding ability in mechanical and thermal conditions. Current NASA R&D with metal heat shielding such as ARMOR would be essential on a next generation orbital space plane.

The issues in reentry are vehicle surface area, wing loading (weight/area ) and air density. The shuttle with a high wing loading flies a profile lower in the atmosphere with a higher BTU transfer rate over time. Lifting body vehicles with higher surface areas offer lower heating rates and support metal thermal protection except for leading edges where carbon-carbon-silica carbide is required. Subsonic L/D values from 4-7 are possible with the right design. The X-20 Dyna Soar or Hope-X programs offer good airframes for consideration in the OSP programs. The X-43 with its stubby wings does not support the metal reentry tile concept due to a low surface area. Its manufacturer needs to go back to the drafting board and rethink its OSP submittals with aerothermodynamics in mind.

The nation needs to consider retiring the shuttles and use the Delta IV for now to launch the OSP and can do so in 5 years if the funding is there. Using the K-1 would also be an idea. And other vendors such as AST offer outstanding concepts well worth consideration.

NASA should look at its prior research efforts and have a focus group with the Air Force and ISS partners to hammed a design out. With the right design, we will arrive with an ISS rescue craft, a manned transport vehicle and can use the remaining shuttle parts for cargo lifting even for a real Mars program at a fraction of a cost. But government has to think out of the box and embrace rapid design and development found in industry to gain success while remaining safety focused.

I know that well, since I have over 20 years in nuclear instrumentation engineering in my professional background. America has suffered a major loss indeed, lets make he right choices and get a better shuttle at a lower operational cost with a metal reentry tile system and crew escape provisions like the capsule had. IT does not take 35 billion and a decade. It takes maybe 2-4 billion in 5 years to get a flying and orbital prototype. And the military would have a strong interest without a question as well.

Dave Ketchledge
Senior NAR and TRA member


 

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