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Vehicle Systems & Configuration Chart
Nuclear pulse propulsion Reconnaissance Mission spacecraft designed for my Orion’s Arm future history setting.
Artwork featured: on Winchell Chung’s Atomic Rockets site, Project Orion page, under William Black's 3D Orions.
Artwork Featured on Realistic Spaceship Illustrations Blog, Link: here
Image is part of a future historical setting, details in my journal entry Orion’s Arm Future History, A Synopsis.
Reconnaissance expeditions fall at +300 years on my future history timeline. A journal post with more detail on this era is to be found here: Martian Earth Return.
A Timeline Graph is to be found here: Timeline.
This is the first in a class of vehicles designed for use during the Martian Earth Return segment of my future history. The three types of vehicles included in this class are: Reconnaissance, Contingency, and Intervention.
A second class of vehicles will include a nuclear pulse HLLV – for lofting heavy payloads to Earth orbit, engineering vehicles with heavy landing craft to prepare landing sites for the HLLV’s, and an interplanetary cargo transporter.
The Martian terraforming program requires a far broader sampling of Earth-life than the initial settlement requirements of food animals and agricultural crops suitable to environment shed farming – so a return to Earth is part of the effort. However …
Earths civilization has collapsed. The causes and conditions of that collapse, the status of any remaining human population, and what might lay in wait for the Martians (a dead world, a human population reduced to savagery surviving in primitive conditions, bunkered enclaves of reactionary military forces, or survivors capable of becoming partners in trade) are all unknowns.
The first phase of the Earth return employs Reconnaissance mission vehicles in order to answer these questions.
The spacecraft is an intelligence gathering platform which employs a sophisticated Electro-optical Hyperspectral/Multispectral imaging array. Crew disciplines bridge expertise in Measurement and Signature Intelligence, (MASINT), Signals Intelligence (SIGINT), and Imagery Intelligence (IMINT).
Electro-optical MASINT has similarities to IMINT, but is distinct from it. IMINT's primary goal is to create a picture, composed of visual elements understandable to a trained user. Electro-optical MASINT helps validate that picture, so that, for example, the analyst can tell if an area of green is vegetation or camouflage paint. Electro-optical MASINT also generates information on phenomena that emit, absorb, or reflect electromagnetic energy in the infrared, visible light, or ultraviolet spectra, phenomena where a "picture" is less important than the amount or type of energy reported.
Hyperspectral sensing allows discrimination of refined signatures, based on a large number of narrow frequency bands across a wide spectrum. These techniques can identify military vehicle paints, characteristic of particular countries' signatures. They can differentiate camouflage from real vegetation. By detecting disturbances in earth, they can detect a wide variety of both excavation and buried materials. Roads and surfaces that have been lightly or heavily trafficked will produce different measurements.
Hyperspectral imaging can detect disturbed earth and foliage. In concert with other methods such as coherent change detection radar, which can precisely measure changes in the height of the ground surface. Together, these can detect underground construction. It can detect specific types of foliage supporting crop identification; disturbed soil supporting the identification of mass graves, minefields, caches, underground facilities or cut foliage; and variances in soil, foliage, and hydrologic features often supporting NBC* contaminant detection.
*(Nuclear, Biological, Chemical warfare)
In a certain sense, the initial phase of the Martian return to Earth presents unknowns of similar scale to what an interstellar expedition might encounter: an unknown world and a potential first contact scenario. The mission turns the NASA nuclear pulse exploration missions on their head, launching from Mars and exploring an Earth which, in the three hundred years since the Martian departure, has become an unknown.
The Reconnaissance spacecraft is the Martian’s first fully re-usable Orion spacecraft – a surface launched spacecraft which performs its mission and returns to a touchdown at its point of origin to be refurbished and used again.
Ground launch is accomplished via rocket assist, firing four engines derivative of the Rocketdyne L-6 – six million lbs thrust per engine – lofting the vehicle to an altitude sufficient to avoid ground-reflection shock waves from the nuclear pulse drive. On mission return, after the nuclear pulse drive has canceled the vehicles orbital velocity, the spacecraft descends using its integral rockets to trim the vehicles free-fall velocity and brake the spacecraft during the last several kilometers of descent to touchdown.
Details on the Rocketdyne L-6 here: Rocketdyne L-6 Engine
At launch first-stage toroidal shock absorbers are protected from the rockets reflected ground-blast by its integral micrometeorite shield. Second-stage shock absorbers are retracted to their full stop position. Rockets loft the vehicle to about 700 feet.
On engine shutdown the rockets are withdrawn into internal bays, engine ports are sealed, the first-stage shock absorber micrometeorite shield is retracted, the second-stage shock absorbers move to their nuclear pulse start position, and nuclear pulse operation is initiated.
An upcoming post will detail the launch site designed to accommodate low-altitude nuclear pulse operation.
Acknowledgement:Special thanks to Rhys Taylor for his input, advice, and time spent in brainstorming these ideas with me. Dr. Taylor's advisement helped shape and constrain the concepts surrounding this type of spacecraft, and the overall concept and form of vehicles involved in this stage of my future history setting.
Related Images:Expedition to Earth
Your concept here is a good derivative of the original Orion designs. Hope something like it - or newer designs like hte Polywell rockets - will be flying soon.
The nuclear pulse propulsion system itself requires no heat radiator at all, the rule is the same as for a nuclear thermal rocket in which the plume carries the heat away, only more so, since the energy from nuclear detonation are never contained as the heated expanding hydrogen is in a NTR.
So all we are concerned with here is the electrical power generating system which requires its own dedicated radiator, if there is a rule of thumb it would be this: you cannot dump waste heat from a habitat into the power system radiators because of the difference between the heat generated by one system verses the other, so of course the habitat along with the waste heat generated by electronics (computers, life support system circulating fans, and so on) use separate radiators.
For purposes of power generation, I postulated a nuclear reactor (of perhaps more advanced design) derived from the SNAP-10a nuclear reactor – image and description available at the link. Note that (in the image) the cone is the radiator, for sense of scale note the two docked Gemini space capsules.
For more information I recommend the following link, courtesy of Winchell Chung’s Atomic Rockets site: Thermophotovoltaic Energy Conversion in Space Nuclear Reactor Power Systems.
If you want to do the math:
∂Q/∂t = Re * (5.67x10e-8) * Ra * Rt4
- ∂Q/∂t = amount of waste heat to get rid of (watts)
- 5.67x10e-8 = Stefan's Constant
- Re = emissivity of radiator (theoretical maximum is 1.0)
- Ra = area of radiator (m2)
- Rt = temperature of radiator (degrees K)
Formula by Ken Burnside, again, courtesy of Winchell Chung’s Atomic Rockets site.