Please be advised that this website has been archived and will no longer be updated. The 20 chapter technical paper and the business plan is only in its first draft and is therefore rendered obsolete. There have been many changes to the design and direction of the paper.

For a detailed treatment of our space concepts as High School S.T.E.M. projects, please visit:

The Management

The City In the Sky

Now that our Skylon space vehicle has a solid base of operations at Spaceport America, we can start flexing our muscles and begin to expand our horizons.

At each step in our journey, we need a base of operations; somewhere to eat, sleep, work, and yes, play. Spaceport America is such a place; it might even be called the Earth Surface Station (ESS).

The first and most logical of these steps is Low Earth Orbit (LEO). And as much as the Spaceport will be a busy place, so too will the LEO Station (LEOS).

As we did with the space taxi, a laundry list of space station features are in order.
  • Ability to be re-boosted to target orbital altitude
  • 72 people (52 Crew + 20 Passengers)
  • 100 kW continuous power (Day and Night)
  • Minimum Orbital Altitude of 365 km (227 mi)
  • Orbital Inclination of 33 Degrees
  • Universal Docking Ports
  • Sea Level Atmosphere and pressure
  • 4.57 m (15 ft) x 12.19 m (40 ft) station module size constraint
  • Ability to be easily assembled in orbit
  • Ability to attach Airlock(s) for EVA purposes
The infrastructure in LEO will be constructed so that it can become the launch-point to anywhere else in space.

Many different kinds of operations will be taking place aboard the LEOS, as with the Spaceport. Flights will be coming and going, maintenance will be ongoing, etc.

The LEOS will have an orbital altitude of 385 km, which is the height that the Skylon can reach loaded with a Passenger Module.

Pressurized modules, delivered into LEO by the Skylon, are joined together to form the LEOS.

The three images below are what the LEOS should look like after being assembled.

Top view of the LEOS:

Side view of the LEOS:

 Front view of the LEOS:

The direction of flight is in the (+)Y direction. The earth-facing side is in the (-)Z direction, and the space-facing side is in the (+)Z direction.

The Skylon spacecraft docks with the LEOS at either end of the modules sticking out from the center, in the (+)Y and (-)Y direction.

Each unit of the LEOS is described below.


Universal Space Interface System Each module will have a Skylon-invented Universal Space Interface System (USIS) at each end (a fancy way of saying Docking Port), which physically connects two objects in space.

Closeup view of Skylon's USIS:

Detailed view of Skylon's USIS with Hatch:


Airlock All modules will have the ability to attach to each other or to another airlock. As is our theme of reuse and commonality, the airlock will incorporate the USIS.

View of the airlock:


It can be used to connect two modules together, or to allow the crew to conduct an Extra Vehicular Activity (EVA), or spacewalk.


LEOS Modules
Each LEOS module will be 4.0 m (13.1 ft) in diameter by 8.8 m (28.9 ft) in length. Modules will be oriented either horizontally or vertically. The LEOS will maintain a consistent "up" direction to help with motion sickness issues.

Modules will (eventually) be wrapped with a kevlar-type material to ward off micrometeorites. These blankets will be flown up at a later time.

Horizontally-Oriented Modules

These modules have a USIS attached to each end.

Side view of a typical horizontally-oriented LEOS Module:

Front view of a typical horizontally-oriented LEOS Module:

All modules will come with eight (8) Environmental Control/Life Support Systems (EC/LSS). They will maintain an oxygen-nitrogen atmosphere at sea level pressure (14.7 lbs psi). When in a horizontal orientation, they line the ceiling and the floor.

Each of these type of modules will have a volume roughly equal to a box with dimensions 2.2 m in height, 4.0 m wide, and 8.8 m long. This means each module has a pressurized volume of 77.44 cubic meters (2,735 cubic feet).

Internal side view of horizontally-oriented module with EC/LSS:

Internal front view of horizontally-oriented module with EC/LSS:

The EC/LSS will contain fans to draw in air to be passed through lithium hydroxide canisters to scrub it of carbon dioxide. Small tanks of oxygen and nitrogen will resupply the atmosphere as needed. They will run independently, with a separate power source. This will ensure that the LEOS is compartmentalized should a hull breach ever occur.

These modules can be modified internally to any desired configuration. Windows can be used for the crews' viewing pleasure.

Berthing Module:
The Berthing module is simply a horizontal module with sixteen (16) sleeping units.

Internal front view of Berthing Module:

The blue area represents the sleeping quarters. The person sleeps upright, violating the "consistent up direction" rule. If desired, the quarters could instead be arranged "bunk-bed" style, and still achieve the 16 person capacity.

Galley/LAV Module: The first quarter of this module contains eight (8) 0.8m (2.6 ft) Shower/Toilet sets. Each set is a collapsible shower curtain that attaches from the floor to the ceiling, sealing them in (sorry). These showers are similar to the one installed on Skylab. The occupant can then do his or her business, making the biggest and stinkiest mess on the station, and it won't matter. Simply turn on the shower to clean it (and themselves) up.

The next section contains the food heating unit. There, breakfast, lunch, and dinner are warmed and served on a tray for the eater to eat. The frozen food trays are entered into the mechanism, and after a certain amount of time, a bell rings, and (like Pavlov's Dog), the person selects a tray and goes to the dining area to eat.

The last two sections comprises the dining area, where people can eat while gazing out the window.

After the meal is completed and the Galley cleaned, stationary exercise bicycles can be un-stowed, unfolded, fastened to the floor, and used to keep the crew fit.

Commons Area Module:
These horizontal modules will be left intentionally empty, and the LEOS occupants will decide what goes in them. An arboretum? A place to display artwork? A low-light area for earth observations? The LEOS crew will decide.

Vertical-Oriented Modules

As with the horizontally-oriented modules, these modules will come with eight (8) Environmental Control/Life Support Systems (EC/LSS). They will maintain an oxygen-nitrogen atmosphere at sea level pressure (14.7 lbs psi). When in a vertical orientation, they line all four walls in one section, to allow an open area in the next section.

Each of these types of modules will have a volume roughly equal to two cylinders with dimensions 4.0 m in diameter, and 2.2 m in height. This comes out to 55.29 cubic meters. The EC/LSS section has a volume equivalent to two cubes with dimensions 2.2 meters on each side. This comes out to 21.3 cubic meters. This means each module has a pressurized volume of 76.6 cubic meters (2,705 cubic feet).

Internal top View of vertically-oriented module with EC/LSS:

Internal top View of vertically-oriented module without EC/LSS:

Bridge Module:
The nerve center of the entire space station, this is where the Captain and the XO are. The EC/LSS modules are located in the top and bottom parts of the module.

Internal side view of Bridge Module:

The two sections in the middle are together to facilitate coordination between the two floors. The bridge receives information about the LEOS itself, as well as spacecraft traffic, systems information on science stations, etc.

Spacecraft Control Module:
This module is attached underneath the Bridge and has the same internal EC/LSS organization as the Bridge. Pilots in this module remotely fly the various spacecraft that operate around the LEOS (to be described in the next diary). The Remote Manipulator System (RMS), or robotic arms, are operated by LEOS crew members in this section as well.

MedicalEngineering Module:
Underneath Flight Ops is the Med/Engr module. Internal side view of the Med/Engr Module:

Sickbay is located at the top portion of the module, to facilitate an easy access into the section. This is where sick or injured people come to for medical treatment, or for general health maintenance and checkups.

LEOS status and other information is gathered in the next section down in the module. The Engineering section houses instruments and equipment necessary to run and maintain the LEOS.

EVA Module:
The idea behind the EVA module is to keep a four (4) person crew (8 total on a 24/7 schedule) always in a 3 lbs psi, pure O2 environment. This makes it very easy to conduct spacewalks, since it eliminates the 7 hour pre-breathing stage needed to purge nitrogen from the body. Also, emergency EVA can be accomplished very quickly.

Internal side view of EVA Module:

The first section of the EVA module is the berthing/Galley/LAV section for the eight crew members (four at a time). Sleeping bags can be stowed on the floor, then the other end attached to the ceiling when in use. There would be only two (2) Shower/Toilet sets. Stationary exercise bicycles would be used between meals.

The bottom section is used for EVA Prep. The crew don and doff spacesuits. They exit and return via the airlock connected below.

This area is also used as the Recreation Area for off duty crew members.

Logistics Module:
This module contains the freezers holding trays of prepared frozen food; refrigerators for fresh fruits, vegetables, and dairy; and storage lockers for other station necessities. The module acts as a garbage receptacle for used trays. When all the food trays are consumed, the module is simply replaced with a fresh module brought up by the Skylon.

The internal top view of the module looks similar to the internal front view of the Berthing module, only vertical.

Internal side view of Logistics Module:

Each Logistics Module can feed 18, and will last around 47 days. That's 846 breakfasts, 846 lunches, and 846 dinners, for a total of 2,538 meals. If each frozen food tray weighed 2 kg (4.4 lbs), that comes to 5,076 kg (11,168 lbs). It is attached near the Berthing and Galley/LAV Modules.


Remote Manipulator System (RMS) This unit is attached to the side of the Spacecraft Control Module. The robotic arms can reach to 20 m (66 ft), which means that it should be able to reach any part of the space station.


Power Stations Renewable energy is a natural fit for spaceflight operations. The LEOS will be powered by four (4) solar power stations, each generating 60 kW of energy, and delivering 25 kW continuously. A total of 100 kW of continuos power will be available for the LEOS.

The power station comes in two (2) parts. The Solar Panel Module measures 4 m x 12 m, (15 ft x 40 ft). When fully deployed, each solar panel side will measure 9 m x 40 m (30 ft x 131 ft), for a total of a 9 m by 80 m (30 ft x 262 ft) of solar panel area.

The Solar Panel Module is attached in space to the Station Power Module. The batteries and other power infrastructure are housed in this module. It is attached to a USIS, where the controls for the power unit itself are located. It then is attached to a standard airlock.


The LEOS Once the modules are manufactured and tested, they are flown into space inside the Skylon spacecraft. There, they are assembled into a functioning city.

The following is a list of LEOS components. It lists the quantity, weight, dimensions, power requirement, and description of each module:
  • (4) - 14,742 kg - 4.0 x 8.8 m - 5 kW - Logistics Module
  • (4) - 14,742 kg - 4.0 x 8.8 m - 3 kW - Berthing Module
  • (4) - 14,742 kg - 4.0 x 8.8 m - 4 kW - Galley/Lavatory Module
  • (4) - 11,000 kg - 4.0 x 8.8 m - 4 kW - Commons Area Module
  • (1) - 14,742 kg - 4.0 x 8.8 m - 6 kW - Bridge Module
  • (1) - 14,742 kg - 4.0 x 8.8 m - 6 kW - Spacecraft Control Module
  • (1) - 14,742 kg - 4.0 x 8.8 m - 6 kW - Medical/Engineering Module
  • (1) - 14,742 kg - 4.0 x 8.8 m - 6 kW - EVA Module
  • (7) - 5,000 kg - 2.2 x 2.2 m - 1 kW - Airlock Module
  • (2) - 5,000 kg - 1.0 x 1.0 m - 1 kW - RMS Module
  • (4) - 14,742 kg - 4.0 x 6.6 m - N/A - 25 kW Power Module
  • (4) - 14,742 kg - 4.0 x 12.2 m - N/A - 60 kW Solar Panel Module
Total LEOS weight: 442,808 kg (976,225 lbs)
Total LEOS power requirements: 97 kW
Total LEOS pressurized volume: 616.16 cubic meters (21,759.49 cubic feet)
Total Number of Skylon flights: about 40 flights.

At 8 Skylon flights per week, that will take about 5 weeks to lift to orbit. Assembly should take another 5 weeks. Total time is 10 weeks to lift and assemble the space station.

The first to be assembled will be the Power Stations. Both modules will be lifted and attached, where the solar panels will spread and generate electricity. 25 kW of continuos electrical energy are now available.

Another Power Station is assembled and attached, for a total of 50 kW of power. Four Berthing modules, four Galley LAV modules, and two Logistics modules are attached to the airlock of the Power Module. The Commons Area module is attached to the remaining opening of the airlock. A duplicate of this arrangement is also lifted and assembled.

The 2 halves are joined together by an airlock. Two more Commons Area modules are also added. The Bridge and Spacecraft Control modules are attached on the top part of this centralized airlock, and the Medical/Engineering and EVA modules are attached at the bottom part. An airlock is attached to the top of the Bridge, and two airlocks are attached to the bottom of the EVA module.

The kevlar-like material is then wrapped around each of the modules. Trusses will be added to strengthen the connections between the modules.

The LEOS is now complete.

Once again, the Top view [(4)Power Stations, (4) Berthing, (4) Galley/LAV, and (4) Commons Area modules shown]:

The Side view [(4) Power Stations, (4) Logistics, (2) Commons Area, (1) Bridge, (1) Spacecraft Control, (1) Medical/Engineering, and (1) EVA module are shown]:

And the front view [(2) Berthing, (2) Galley/LAV, and (2) Logistics modules are shown]:

Immediately, the space station begins to fall back to earth. We estimate an average orbital decay rate of around 4 km per month. At that rate, the LEOS will fall 20 km in five months. We estimate a total delta v requirement of about 7 meters per second to re-boost the LEOS back to 385 km.


LEO Science Stations (LEOSS)
These are smaller space stations that orbit independent of the LEOS, but in the same orbit relatively close by. Think of them as the suburbs of our "City In The Sky". For the scientists aboard, it will be like having their very own space station!

They are made up of various modules that were described above. In addition, they have four (4) science modules; two that are horizontally-oriented and two that are vertically-oriented.

Any type of science can be conducted aboard these suburbs. The most obvious is astronomy, however other uses would be encouraged as well, such as an LEOSS devoted to separating proteins using the gel electrophoresis method. We are confident that other science projects can be designed.
  • (1) - 14,742 kg - 4.0 x 8.8 m - 5 kW - Logistics Module
  • (1) - 14,742 kg - 4.0 x 8.8 m - 3 kW - Berthing Module
  • (1) - 14,742 kg - 4.0 x 8.8 m - 4 kW - Galley/Lavatory Module
  • (4) - 14,742 kg - 4.0 x 8.8 m - 8 kW - Science Module
  • (4) - 5,000 kg - 2.2 x 2.2 m - 1 kW - Airlock Module
  • (2) - 14,742 kg - 4.0 x 6.6 m - N/A - 25 kW Power Module
  • (2) - 14,742 kg - 4.0 x 12.2 m - N/A - 60 kW Solar Panel Module
Total LEOSS weight: 182,162 kg (401,598 lbs)
Total LEOSS power requirements: 48 kW
Total LEOSS pressurized volume: 309.76 cubic meters (10,939.07 cubic feet)

The 2 Power Station modules are assembled. One Station gets four (4) Science modules; 2 vertically oriented and 2 horizontally oriented. The other Station gets the Logistics, Berthing and Galley/LAV modules. The 2 halves are joined by an airlock. Another airlock is attached at the bottom of the airlock attaching the Logistics module.

Top view of an LEOSS:

Side view of an LEOSS:

Front view of an LEOSS:


Personnel The LEOS is fully staffed with a crew of 52 and 20 passengers.

Crew rotation for the LEOS and all the LEOSS's are as follows:
  • Five (5) months Duty in space
  • Three (3) months Off Duty
  • Two(2) months Training for the next Duty cycle
The entire staff and the passengers will be divided into two groups. Each group works a 12-on, 12-off shift, i.e., a 12-hour duty day followed by 12 hours off. The sleep period occurs during the off hours. While this may seem costly in terms of the number of people having to be kept alive in space, the tradeoff is that this cycle also ensures a 24-hour, 7 day-a-week space operation.

Each opposite Berthing/Galley/LAV module cluster on the LEOS will house the Day or Night shift personel. This ensures survivability should a portion of the LEOS becomes disabled.

During emergencies, the Captain remains the Captain. Each position is equal. If a change of personel is due because a shift is ending/starting, it should only be done if needed. Otherwise, the emergency comes first.

The daily schedule is as follows:

Day Shift:
0430 - 0530: Wake Period
0530 - 0630: Breakfast
0630 - 0700: Shift-Change Handoff
0700 - 1130: Shift
1130 - 1230: Lunch
1230 - 1730: Shift
1730 - 1830: Dinner
1830 - 1900: Shift-Change Handoff
1900 - 2230: Off Duty
2230 - 0430: Sleep Period

Night Shift
1630 - 1730: Wake Period
1730 - 1830: Breakfast
1830 - 1900: Shift-Change Handoff
1900 - 2330: Shift
2330 - 0030: Lunch
0030 - 0530: Shift
0530 - 0630: Dinner
0630 - 0700: Shift-Change Handoff
0700 - 1030: Off Duty
1030 - 1630: Sleep Period

This schedule is followed for the EVA and LEOSS crew as well.

Command Structure:


Flight suits will be worn and be of the following colors:

Black: LEOS Crew
Blue: Pilot
White: Medical
Science-Biological: Green
Science-Non-Biological: Tan
Orange: Tourist

The tourists wear orange because that is the best color to see in case of an emergency. They stay a total of one week in space.

The LEOS personel breakdown is as follows:

(30) LEOS Crew
(18) Pilots
(04) Medical
(52) LEOS Crew

(20) Tourists-Orange
(72) Total people onboard the LEOS at any given time.

All flight suits will have their rank insignia worn on their sleeves, Navy-style.

Crew Rank:
(02) Captain - Commanding Officer (CO)
(02) Commander - Executive Officer (XO)
(04) Lieutenant Commander - Department Heads
(14) Lieutenant - Division Heads
(30) Lieutenant, Junior Grade - LEOS Crew Members
(52) Crew

All Ensigns are trainees who will rotate to flight status upon completion of their (standard) astronaut training.

(Full disclosure: I used to fly backseat in Navy jets off of aircraft carriers, so that is the reason why I seem partial to Navy Officer rank and insignia, even though I served as a Petty Officer, 2nd Class; but then, that's another diary!)

Six (6) crew from Engineering (2 LTs and 4 LTJGs) plus two (2) Pilots (LTJGs) will rotate to the EVA module every week. This ensures that Engineering crews pull EVA duty once a month, and that pilots pull EVA duty once every 6 weeks.

The other three (3) LT-LTJG-LTJG combinations rotate duty. After a week in the EVA module, it is on to a week performing general LEOS maintenance (changing out the lithium canisters, cleaning throw-up, etc.), then one week performing RMS operations and communications, then a week tending to the tourists. They also all perform duties involving routine satellite maintenance, assembly, placement, etc.

Pilots will operate remote stations that operate spacecraft used around the LEOS and other places (this is a topic for a future post).

The medical personel consists of a LT Medical Doctor and a LTJG Physician's Assistant.

Onboard an LEOSS, the command structure is as follows:

(06) Crew-Black
(10) Science-Green or Tan
(16) People

Crew Rank:
(02) Lieutenant Commander - Commanding Officer (CO) and the Ph.D.
(02) Lieutenant - Executive Officer (XO)
(02) Lieutenant - Lab Assistants
(04) Lieutenant, Junior Grade - LEOSS Crew Members
(06) Lieutenant, Junior Grade - Lab Technicians
(16) Crew


We now have a place for passengers and crew to actually visit and live in space. Once that capability has been reached, getting some actual work done in space is then easy to do. Eventually, even a second city will be assembled, complete with its own suburbs.

But for now, our city in space is ready for the next phase. This will include the need to maintain, operate, and refuel spacecraft, so that we can even further expand our horizons.

But that's a topic for another day.


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