July 17, 2010

Low Earth to Geosynchronous Orbital Spacecraft

One of the oft quoted memes, usually by proper rocket scientists to armchair astronauts, is that “Rockets are not LEGOs.” But what if they WERE!

For this to work we must assume a New World Order. As I write the world is in the process of designing no less than six different space to ground [S2G] ballistic capsules:  Orion CEV (NASA);  PPTS (RKA); Dragon (SpaceX); ARV (ESA); ‘Ratri [1] ‘ (ISRO); CST-100 (Boeing).  The capsules already in service Shenzhou (CNSA) and Soyuz (RKA) bring this total to eight. The DreamChaser(SpaceDev) -not a capsule- makes nine. Talk about needless duplication of effort!

So for the purposes of this thought experiment, this Future Historian assumes that “The Collapse” has happened: a confluence of resource depletion; water wars; global warming; eco-collapse and a mass extinction of the human population. Hurrah! The survivors have picked themselves up, formed a stable world govenment/ workers paradise and discovered they have one last chance to get Out of the Cradle. If they mess it up this time there are no second chances and the future is a one planet culture until the Sun inflates and makes us ALL a Galactic Might Have Been. Alternatively if we can avoid all that sort of thing. This sort of thing might be a sensible way forward.

First stage. Cheap access to space: Skylon. Crash program. NOW! Sorted.

O.K. Perhaps a two stage to orbit variant or even an equatorial Mag Lev launch track at high altitude to further improve efficiency. But I digress…

Without cheap access to space we remain DOOMED. Disposable rockets are an unsustainable technology. Heavy Lift an unsupportable technology. A reusable launch system remains our only long term option.

Now what does it launch so that we can harvest the Asteroids and start to incorporate the resources of the Solar System into our worker’s paradise?

Second Stage. Modular space craft: LEGOS.

The following borrows heavily from the:

“Soyuz Evolution: Vestrecha “Reunion”- a series of long term and long duration manned space utility vehicles (SUVs)” (Anglo-Russian Co-op., Project Congreve.)

All crewed SUV modules:

  • fit inside a nominal 5 cubic metre box with notional interconnects on the faces of that box
  • have at least one next generation: androgenous and active autonomous docking system [A4DS]
  • are capable of remote operation and autonomous rendezvous and docking
  • at least one Universal Common Berthing Mechanism hatch with a 130 cm square opening. (Just to be different!)
  • internal whipple shields for orbital debris
  • external attachments for kevlar / thermal padding, cable routers, handholds, Space Station Remote Manipulator [SSRMS] grapple fixture (or equivalent)
  • integrated power systems inc. solar array (detachable); batteries (rechargable and replacable); mechanical charger (emergency); power bus (universal)
  • integrated and automatic power inter-connectors between modules providing a universal bus
  • a wired backup for communications and computing via the universal bus
  • integrated wireless communications and computing network
  • integrated thermal control cooling loop and automatic inter-connectors between modules
  • an emergency distress beacon
  • minimal ship to ship, ship to ground communications
  • limited life support: CO2 scrubbers; oxygen reserve; emergency food and water supply

and critically

  • long term durability in the space environment. Entirely space based, all systems would be re-designed to maximise ease of maintenance and repair in zero-gee: externally and internally.

Crew Modules
Vs-G Orbital Command Module [2 x A4DS] “Gagarin” At present the CEV/ PPTS re-entry module and command module are one and the same. The Vs-G has the re-entry capabilities removed but retains and extends those required for orbital manoeuvre: navigational platform; command, control and communications; integrated attitude control systems and wireless links to remote attitude and main manoeuvre rocket motors. Includes: workstations for ROV operations: minimal personal  hygiene compartment, extended life support, food storage and reconstitution facility. Normally docked to an upgraded Service and Propulsion Modules (u.i.), the VsG is thus provided with power, life support services [LSS], tankage and motor capacity for long duration flights with minimal crew (2 fixed seats). Short duration crew (fittings for 10 minimal acceleration hammocks) for transport between stations, habitats, deep space vessels or free flying platforms, from a deep space vessel to the surface of an asteroid;… and as an emergency return of crew (as many as can be crammed in) from the Lunar Orbital Outpost; L1/ L2 Gateways or other cis-lunar habitats. The VsG would include the latest in ‘fly by wire’ and auto-piloting/ naive operations support. Whilst various standard operations: in flight refuelling; rendezvous; docking; course correction and other critical operations will be manually achievable by suitably trained pilots; they should be rarely required!

Vs-L Orbital Work Module [1 x A4DS, 1 Airlock Hatch] “Leonov” An enlarged version of the Pirs/Poisk orbital module this becomes the location of hazardous activities: notably the Mk. X zero gee Toilet [2].
Module has internal fittings for four Next Gen SpaceSuits and MMUs; equipment for the recharge and maintenance of same; a separately pressurised vestibule for EVA preparations; airlock;…  Also standard fittings for Univeral Standard Payload Rack used for potentially hazardous experimental packages. Module has external fittings for EVA support including inflatable vacuum porch and illuminated external work platform. EVA consumables resupply, equipment storage,…

Vs-K Orbital Habitation Module [1 x A4DS] “Krikalev” This Module evolved to become a ‘safe haven’ with better radiation protection; Closed Loop Life Support  Systems [CLLSS]; compact zero gee kitchen, food storage and mess; group entertainment/briefing/’window’;  personal hygiene facilities: toilet and fresher. Provides accommodation for four (to eight) additional passengers. This may be adapted from the proposed conversion of the Integrated Cargo Carrier (ATV) into a “Habitation Module” as part of the PPTS.

Vs-V Lobby Module [6 x A4DS] “Volynov” Non-maneuverable. Largely identical to the proposed Russian multiple docking node with six UCBM docking ports/ hatches. Integrated power and life support nodes. Enables the construction of multi-module craft specialised for long duration missions.  Exterior has even more external attachments for cables.

Vs-F Repair and Construction Module [1 x A4DS, 1 Airlock Hatch] “Feoktistov” A specialised combination of the Vs-G and Vs-L optimised as a “shirt sleeve” construction tug for ‘hands-on’ large scale projects: SPS deployment; Habitat construction; recovery of spent kick stages; transportation of small asteroids;… Exterior has attachment points for a variety of remote manipulators and external tool kits.

Vs-B Re-entry Module [1 x A4DS, 1 Escape Hatch] “Belyayev” An enlarged version of proposed CEV/ PPTS re-entry modules with a long life de-orbit solid/ hypergol retro pack; hypergolic attitude control thrusters; ballute; parafoil wing; flotation bags; landing thrusters;… This Module is evolved to become capable of naive Space to Ground (S2G) transfers with an automatic re-entry capability; carrying incapacitated crew (minimally seven), or just a single frightened tourist! Initially only the interior fittings will be reuseable. With modifications, eventually valuable exterior sub-assemblies should be capable of re-use. Ultimately utilising a disposable aeroshell or ballute the Vs-B core will be wholly reusable. Range: anywhere in cis Lunar Space. Evolving to Cis Terran Space (SEL1 to SEL2).

Vs-T Greenhouse Module [2 x A4DS] “Tsiolkovski” In addition to the extensive CLLSS systems, this human tended module would contain a hydroponics facility not only for fresh foods: herbs, spices and other high value plants but an essential ‘connection’ with nature.  Carniculture and myco-protein reactors would be supported by aquaculture tanks located toroidally around the module providing radiation protection and a source of fresh protein.

Other Modules would support a Spin component. Notably a Vs-V Spin Isolation Hub with four hatches to two, or four, spin modules incorporating tether mechanisms. Once sealed and lowered into place, these modules could provide: Medical, Gymnastic, Hygiene, Experimental and other facilities where spin gravity is required. These would either incorporate a counter spinning flywheel  or on larger deep space vessels be installed as counter rotating pairs.

Support Modules

The form and function of the existing Soyuz service module [PAO] and all proposed Service Modules are divided into separate propulsion and life support modules. Both provide power via solar arrays, batteries and fuel cells; naturally feeding into the universal power bus.

Vs-N Long Endurance Chemical Propulsion Module “Nikolayev” [1 x A4DS] Requires Orbital Propellant Repository [OPR], International Space Station [ISS]; Lunar Orbiting Outpost [LOO], Nearside Station [EML-1] Farside Station [EML-2] and eventually transportation nodes beyond. Currently the Soyuz has a ‘life in orbit’ of six months with plans to extend to one year. This relatively short period of ‘cool soaking’ must be extended to a full ‘cold soak’. Ultimately with an indefinite duration ‘cryo soak’. Initially using ‘green’ hypergolics and then ‘zero boil off’ LOX/LCH4[3] tankage; used for both main propulsion and RCS. Propulsive systems and flight electronics must be capable of being prepared for a prolonged ‘cryo soak’. In a similar manner to that of a family leaving the house for an extended winter holiday: the plumbing is drained of highly diffusable helium, cryo-propellants LOX (54.36 °K ) LCH4 (91 °K) ,… temperature sensitive equipment will be buffered using a suitable fluid, circulated via radiators, to maintain an even temperature; gyros will be spun down; most of the solar arrays retracted; batteries set to trickle charge from a singular array or external source;… In this condition the module will be capable of being docked to some facility as a last resort backup; a non-emergency return vehicle  (LOO) or spare rescue craft (ISS).

Vs-P Long Endurance Service Module “Polyakov” [2 x A4DS] Principally applied to non-closed chemical and mechanical methods of life support. Whilst attached to a node in a ‘warm soak’ would see the principle consumable: water plumbed in as part of the CLLSS or as radiation protection of that node. For a ‘cold soak’ the water would be drained while other systems: atmospheric filters, CO2 scrubbers, would be robust enough to withstand the cold. Electronics and sensitive mechanical systems would be buffered in a similar manner to those of the VsN. This module would not only provide LSS for  spacecraft returning from a distant target but also act as emergency LSS attached to a free flying orbital outpost/ space refuge attached to an automated facility.

Vs-S Long Range Chemical Propulsion Module “Sevastyanov” [1 x A4DS] Studies have shown that a nuclear engine is too mass intensive for short duration/ short haul missions. Short of a breakthrough beyond existing studies, notably: LANTR (Lox Augmented Nuclear Thermal Rocket); TRITON (Pratt Whitney Rocketdyne [pdf]) or a Nuclear powered VASIMR (Ad Astra Rocket Company) Or public acceptance of, say, a next generation pulsed bomblet system such as  MiniMag Orion; the routine operation of a nuclear vessel in cis-lunar space is unlikely. Even when the exploration of NEO asteroids, the moons of Mars and the industrialisation of the Main Belt takes place; there still will be a place for a LOX/LCH4 motor optimised to the space environment. Especially if the propellants concerned can be obtained off Earth: utilising an atmosphere skimming Hydrogen propellant factory PROFAC and lunar derived oxygen LUNOX. The starting point is an upgrade of the wide belled Apollo Service Module engine: burning LOX/LCH4 upscaled from the XCOR/ATK Methane Motor.
In addition to the durability and reliability obtained from the Long Duration variation; this Module should be capable of being repaired a long way from any orbital ‘spacedock’. The module comprises multiple motors/ nozzles and a core ‘inboard’ propellant capacity, complemented by attachment points for stageable external tanks. The latter could carry beacons to allow eventual recovery/ reuse.

(VsT+ Long Range Service Module ) “Tsiolkovski Mk2” Long term life support will probably require more than just tankage and will require regular access for sowing, weeding, pruning, harvesting and general tender loving care. Resembling his “cosmic greenhouse” this module will be largely uncrewed with a CO2 rich and water saturated atmosphere.)

Long Range Ion Propulsion Module An autonomous SEP Tug based on the CLIPPER Program.

From the above Modules a variety of Space Utility Vehicles can be configured in orbit suited to the task at hand. Large scale passenger transit can be achieved by a cluster of Vs-K attached to a Vs-G+Vs-N; emergency repairs by a Vs-F; refurbishment of a free flying facility by a Vs-L and a Lunar Orbiting Outpost (LOO) constructed by an appropriate assembly of modules integrated to the Lunar Orbital Propellant Repository (LPR). Similarly stations at the various Lagrangian points gain modularity, redundancy and reconfigurability. Such Modules also become the basis for bases on Phobos & Deimos and other NEOs until we start to terraform these worldlets into habitats!


1: This author’s designation: Hindu goddess of Night.

2: Space Potty humour

3: LH is just too volatile and valuable to be wasted as ‘boil-off’!

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