On the topic of crew size, Matt Picio said that a modern wet-navy warship averages 15-20 crew members per kiloton of displacement.
However, a more accurate measurement takes into account "core crew", the minimum number of watch-standers to steer and fight the vessel. Core crew is about 80, and represents the minimum number of crew for a long-duration warship. Additional crew is fairly linear, at 1 crew per 100 tons of vessel. Automation will eventually halve these figures.
Ken Burnside says that for routine operations of a warship, you need a minimum of 10 people. Combat is, of course, far from routine. There are many complicated factors involved. For a back of the envelope calculation, figure roughly 10 to 16 crewmen per kiloton, though the lower end figure presupposes that most of the tonnage consists of armor and other things that do not require babysitting. If it sucks current, has moving parts, or works with a pressure or temperature differential, it needs babysitting.
For estimating the crew size of a long-duration military vessel, Sean Schauer has created a nice Excel spreadsheet (instructions are on last page). You'll have to decide how many shifts or "watches" there will be in a 24 hour period, generally from three to six. The spreadsheet was designed for a real-life wet navy vessel, so you may have to adapt it a bit. If you use this spreadsheet please give Mr. Knight credit for it.
Civilian ships average 10 to 25 crew members, depending on size (container ships and supertankers). Liners have about 0.8 to 1.2 crew for every passenger.
Adjust these figures to match your vision of spacecraft crews.
Figure on crew members being from 68 to 113 kilograms each (150-250 pounds). Although if the Solar Guard has any sense, there will be a maximum weight limit on rocketmen. One hopes that there will not be a chronic problem with bulimia in the Guard.
Keeping in mind that everybody knows the Polaris only needed Tom Corbett, Roger Manning, and Astro for crew. Tom was the captain/pilot, Roger was the astrogator/communications/radar man, and Astro was the propulsion system engineer. And on the StarDuster, you only had Scott McCloud (the Space Angel) as captain/pilot, the lovely Crystal as communications/radar/nav, and Taurus as the engineer/gunner.
The problem with that set up is When do they sleep? Obviously you need at least two crewmembers for each post that has to be constantly manned, or hope that the mission doesn't last longer than a day. Caffeine only goes so far.
In spacecraft as shown on movies and TV, they often use the "bomber crew" model. That is, a crew like a World War II bomber aircraft. This generally takes the form of a crew of half a dozen misfits each with some specialized talent needed for a successful finish to the mission.
And don't forget the crew in FORBIDDEN PLANET. As in many wet naval vessels, a lot of the enlisted men are going to be boys around 18 years old.
Once you have established the size of the crew, you can start allocating space for their quarters and supplies for food & life support.
On spacecraft in general, and military spacecraft in particular, there will be a strict "chain of command." People with no management or military experience may not see the point behind a chain of command, but if such a person is suddenly given the task of managing a project (even a high-school bake sale) they will suddenly discover why it is vital. Attempting to run a spacecraft by a democracy or other laissez-faire system will probably result in the destruction of the spacecraft and the death of all the crew. Space is a far too deadly environment and spacecraft are far too full of dangerous equipment to leave things to chance.
In other SF, one will find Captains, Pilots, Owners-Aboard, Astrogators, Doctors/Medics, Engineers (propulsion engineers are sometimes called "Jetmen"), sensor officers/radarmen, Cargo-masters (also in charge with negotiating trades), communications-techs, turret-gunners, life-support techs, marines (space-ines?, Espatiers?), cooks (could be a rotating job), pursers, and sometimes a ship's cat (to catch those pesky alien rats). Maybe a science officer if you have one of those unvirile exploration ships.
In Andre Norton's Solar Queen novels, she mentions that the ship's cat is trained to present the carcasses of the vermin they kill to the captain. This allows the captain to be aware of what sort of alien rats and cockroaches infested the ship at last planet-fall. In his short story "Feathered Friend", Arthur C. Clarke remembers the history of mining, and suggests that a pet canary might be a cheap back-up for an atmosphere monitor. If the bird keels over, grab an oxygen mask and check the life support, pronto!
Space engineers may be faced with the daunting task of designing a microgravity cat litterbox that a cat will actually use. Since there do exist some modern-day cats that have been successfully toilet-trained, it is not impossible to imagine a cat trained to use one of those free-fall suction toilets such as are used on the Space Shuttle.
Of course if this is a tramp freighter, one person might have to do several jobs at once (wear several "hats"). Often the Captain, the Pilot, and the Astrogator are the same person. Or if things are really tight on the tramp, some of the jobs might be omitted (e.g., don't carry a doctor and hope nobody gets sick/injured and similar insanely dangerous decisions).
For purposes of comparison, here is a list of the crew complement of a World War II LST ship. Interesting jobs you will note are Shipfitter, Motor Machinist and Fireman. The LST has seven officers and 104 enlisted men.
If the spacecraft has a large enough crew, there will be a First Officer. Generally the Captain's job has to do with things external to the spacecraft (where the ship is going, what it does when it gets there, etc.) while the First Officer's job has to do with things internal to the ship (ensuring that the crew can and will do their jobs, keeping the ship supplied and in good repair, etc.) The first officer on a small ship is responsible for creating the "watchbill" for all crew members. This is a document specifying the watch rotation for the crew, it tells the crew who has to be where and when. On a larger ship, the department heads will be responsible for creating the watchbill for their department. There will be a different watchbill depending upon whether the ship is in space or on a planet. Crewmembers who are currently on watch are called "watchstanders."
Pilots and helmsmen direct the spacecraft. Pilots might be rated according to the deltaV levels, ship classes, and trajectories that they are qualified to handle. Master Pilots are rated for any and all. The captain give the astrogator the destination. The astrogator plots the course, tells the pilot where to go, and notifies the pilot of navigational hazards. The doctors and medics heal the crew.
The bulk of the engineer's time is taken up by maintenance. Every single piece of equipment and installation has its own maintenance schedule, and it must be inspected, cleaned, serviced, or replaced as per schedule. Sometimes non-engineer crewmembers are assigned some maintenance tasks. A basic preventative maintenance task is simple cleaning. Not only does dirt cause malfunctions, but it also lowers morale.
The other critical task of the engineers is damage control, although all crew members have some basic DC training. The focus is on fire-suppression, controlling decompression, and keeping the ship operational. The idea is to stabilize the damage as quick as possible until time allows more permanent repairs.
Belowdecks during a damage control operation the chain of command may shift. The Damage Control Officer (DCO, often but not always the chief engineer) has the authority to yank personnel from whatever department is needed in order to keep the ship operational. The DC officer creates damage control parties, each of which is responsible for a particular section of the spacecraft. The parties get their orders from Damage Control Central (DDC) which is a watch center generally in the hardest-to-damage section of the ship. The parties give progress reports to the DCO so the ship's status can be tracked. The parties utilize the damage control lockers in their assigned section. The crewperson in charge of each party generally is well trained in shipbuilding, firefighting, and team management.
Sensor officers are the spacecraft's eyes. Cargo-masters deal in cargo and trading. Quartermasters are in charge of ship's stores, and are generally stuck with all the odd jobs that don't fit in any other jurisdiction (e.g., laundry).
Communication techs are the ship's ears and mouth. They direct incoming messages to the proper departments and send outgoing messages in the proper format to the proper channels. Communication noise must be monitored and auxiliary channels used if required. All messages must be logged. Distress signals are sent to the watch officer, but never responded to without authorization. Responding binds the ship to render assistance, a decision reserved for the captain. The communication tech must also maintain the ship's transponder, which broadcasts the ship's ID. The tech may also be responsible for encrypted communications, using the proper keys to encrypt and decrypt, and destroying the code book if the ship is captured by a hostile power.
If the ship is privately owned, the owner might be along for the trip as the "owner-aboard". If the owner is not aboard, they will sometimes appoint a "ship's husband". This is a crewmember who represents the owner, and who manages its expenses and receipts.
There are also "unofficial" jobs onboard. These are colorful characters often found among the enlisted men. Preacher, Loan Shark, Moonshiner, Peddler (the man who always has something to sell, and who can get you anything you want), Bookmaker (place your bets, gentlemen...), Thief, Coward, and Gritch. The latter is the man everyone loves to hate, and the most important character in any small, closed social system.
On whussy exploration ships, in addition to a large number of specialist scientists drawn from various fields, it might be advisable to add a researcher who's job title is "Synthesist". This is a person who can correlate apparently unrelated facts from different areas of science. For example: a Synthesist might notice that a new statistical technique developed by life insurance adjustors to deal with populations of people could be used by astronomers doing surveys of populations of stars. Ordinarily the astronomers would never learn about this technique since they have no area of overlap with life insurance science, but the Synthesist could make that correlation.
There were Synthesists in John Brunner's STAND ON ZANZIBAR, Synthesists in James Hogan's Inherit The Stars, "Nexialists" in A. E. van Vogt's VOYAGE OF THE SPACE BEAGLE, and members of the Mnemonic Service in Isaac Asimov's "Sucker Bait."
In a post to his always insightful blog Rocketpunk Manifesto, Rick Robinson points out how cruel reality has stolen the romance from space crews in general and astrogation in particular. In the classic Tom Corbett Space Cadet books, spacecraft had a pilot, an engineer, and an astrogator for crew. In Robert Heinlein's immortal novel Starman Jones, in the days before a ship reached the FTL jump point, the astrogators worked 24 hours a day, leafing through books of ten place logarithms until the pages fell out and working slide rules until they got hot enough to catch on fire. The only computers they had were hulking brutes that only accepted numeric input in binary via flipping toggle switches on the panel. Certainly nothing resembling a GUI interface with a mouse and keyboard.
But this seems so quaint now. On the high seas, it is considered passé to shoot the sun with a sextant and sweat over a chart with a pair of dividers. Instead you turn on your GPS unit and use your favorite navigation software on your laptop. Unless you are writing a hard-core rocketpunk SF novel, it will be odd to find a slide rule on a starship.
The same goes for most other jobs: much labor will be replaced by automation and computerization.
In Larry Niven's The Borderland of Sol, he postulates a technobabble gizmo called a "mass sensor" which is a "psionic" device. It warns of gravity fields which will destroy starships using Niven's FTL drive. The psionic device can only be watched by a living being, a computer cannot use it for some silly hand-waving reason or other. Niven invented it because he wanted to write about human starship pilots, not write about starships that flew themselves under computer control. Burnside's Zeroth Law, you know.
Of course I personally would be thrilled to have some sort of hand-waved FTL drive that has the side effect of forcing the use of slide rules. I keep trying to come up with one, but so far none my inventions has been free of unwanted side effects. It's hard to think of something that will kill a computer but not the crew.
Rick's solution is brilliant. He notes that current NASA space probes are not navigated by on-board computers. They are navigated by Mission Control. The idea is that the ship is not run by crew members doing things manually. The ship is run by system managers who oversee and command the computers who directly run the ship. This is not quite as nostalgic as the "bomber crew" model of spacecraft crews, but it is far better than a ship with a single button on the control panel labeled "Do Mission".
(note: if you want the precise details of every single control panel in Mission Control, you can find the details here)
Raymond McVay of Blue Max Studios took this idea and ran with it. In a series of blog posts here, here, and here he actually did some research on NASA's mission control with an eye to adapting it to spacecraft crews.
|Mission Commander (MCOM)||This is the overall director of the entire operation, the big boss. If there are several spacecraft in a task force, there will only be one MCOM as task force commander, aboard the flagship. In other words, not all spacecraft will have an MCOM on board.|
|Flight Commander (Flight)||This is the director of the spacecraft in particular. They supervise all aspects of the ship's preparedness and abilty to perform the mission given by MCOM. This would be the ship's "captain".|
|Integrated Communications Officer (INCO)||This is the supervisor of all exterior and interior communications. They are the bridge between all the spacecraft's computer networks, the ship's personnel, MCOM and Flight. This is partially the equivalent of a Naval vessel's executive officer. INCO is also in charge of administrative details and discipline among the other departments.|
|Flight Engineer (Chief)||The supervisor in charge of all engineering systems. If this is a huge spacecraft or space station, this job might be split into several Flight Engineer positions: power, propulsion, maintenance, etc.|
|COMMUNICATION AND ASTROGATION (COMAST) (subordinate to COMMAND)|
|Guidance Procedures Officer (GPO or Guidance)||They monitor the navigation of the spacecraft, ensuring that the guidance control software is operating properly, and keeping an eye out for hostile electronic warfare.|
|Guidance, Navigation and Control Systems Engineer (SYS or System)||They are responsible for teh guidance, navigation, and control system hardware. This includes flight computers, radar, lidar, flir sensors, attitude jets, and all the connections. They direct repair robots perform spot inspections.|
|Spacecraft Communications (SCOM)||The communicator between the spacecraft and other ships or stations.|
|ENGINEERING (subordinate to COMMAND)|
|Propulsion Engineer (Prop)||Officer in charge of the entire conventional propulsion system, from propellant to exhaust nozzle. They also keep track of remaining delta V capacity.|
|Drive Engineer (Drive)||Responsible for hand-waving FTL star drive, heat radiators and maintenance on weapons systems.|
|Electrical Engineer (EE)||Responsible for power plant, power plant fuel supply, and electrical systems. They are also responsible for monitoring radiation if the power plant or propulsion system emits any.|
|LIFE SUPPORT (subordinate to COMMAND)|
|Environmental Consumables Manager (ECM)||This officer ensures that there is enough food, water, heat, and breathing mix to keep the crew alive. Everything from food storage to air vents to water faucets to air scrubbers.|
|Closed-Ecology Life-Support Systems (CELSS or "Cells")||Responsible for the hydroponics and algae tanks, if the ship is equipped with such.|
|Flight Surgeon (Doc)||Medical officer. They deal with disease, injury, ship cleanliness, and radiation.|
|PAYLOAD (subordinate to COMMAND)|
|Payload Officer (PLO/Payload)||They are actually the weapon officer in charge of firing weapons at hostiles.|
|Payload Deployment and Retrieval Officer (PDRO or "Padro")||In charge of loading and unloading cargo. Robots do all the work. Also in charge of ensuring that the cargo is stored in a balanced manner so the spacecraft does not fall off it's tail.|
|Maintenance, Mechanical Arms, and Crew Systems Officer (MMACS)||Officer oversees the maintenance of all the spacecraft's robots, robotic arms, and associated systems.|
Naturally on smaller spacecraft some officers will be responsible for several positions (they will wear more than one "hat"), and some positions will have no human officers.
On larger spacecraft, Raymond thinks that they will have two full mission control teams on board for redundancy. This means six staffers per department instead of three, no officer will wear more than one hat, and all positions will be filled. Raymond figures that if the ship is in a non-combat situation, you'll only need one crew member per department on duty at any given time. This means the normal crew per watch is five. All staffers will be qualified to stand watch for their entire department under normal operations. With low ranking crew members, their main job will be deciding whether to wake up their superior to deal with any sudden situations.
With a full set of 16 filled staff positions, this will boil down to a watch bill with 6 four-hour shifts. Each member of the Command Department functions as Flight Director for their Watch, though only the two Flight Commanders are referred to as "Flight". The INCO is the de facto Executive/1st Officer of a spacecraft, and the Chief is the de facto 2nd Officer. The Watch bill is staggared as well, with Flight 1 directing the first Watch and Flight 2 directing the 4th.
Outside of their four-hour watch, each crew has four to eight hours of specialty work. This boils down to supervising teams of robots and performing spot inspections.
The watchbill is different under non-normal high-priority combat conditions. Combat ships be designed with two separate Flight Control Rooms (FCR) spaced widely apart so that a lucky hostile laser strike does not wipe them both out with one bolt (in Star Trek the second room is called the Auxiliary Control Center). During combat both FCRs will be fulled crewed. The FCR crewed by Flight 1 (and MCOM 1 if present) will be the primary control room, Flight 2 and the deputy MCOM will be in the secondary control room. The secondary control will be on standby, ready to immediately assume control if the primary control room is quote "lost" unquote. "Lost" means anything from "the communication lines were cut" to "the room and everbody in it was just vaporized by a casaba howitzer."
During non-combat periods the two control rooms will conduct regular wargames against each other to keep the teams honed and in fighting trim. And of course the MCOMs and Flights will spring drills and suprise inspections on the rest of the crew to keep them on their toes.
Robert Davidoff said:
As previously mentioned, things are different on a small spacecraft with limited crew. Please note that Raymond has added an external constraint. On the one hand he wants something logical and plausible. On the other hand he is using this to design a role playing game, where the average number of players is about five but occasionally an even lower number (down to one). This somewhat arbitrary limit is also useful for SF authors in order to keep the number of characters down to a manageable level. Of course in reality each additional crew member does add a sizeable mass-penalty with the body mass and the mass of the consumables they will require. So reality also has motivation to make the number of crew members as small as possible, in order to maximize the amount of mass devoted to payload. Emphasis on the "pay", as in "units of stuff that our clients will pay us money for delivering with our spacecraft."
Raymond examined the crew positions on NASA's Space Shuttle to get an idea of what was required. This is what he came up with:
|Flight Commander (FCOM)||The Skipper, and maybe emergency pilot. Not to be confused with "Flight" on a spacecraft carrying smaller spacecraft.|
|Guidance Procedures Officer (Guidance)||Primary pilot. Monitors flight computers, does incidental manual maneuvering, and lands the spacecraft during ionization blackout. Also electronic warfare, if this is a military spacecraft.|
|Flight Engineer (Booster/Chief/Drive)||In charge of maintenance, electrical systems, propulsion, and power reactors. Supervises large teams of maintenance drones and robots.|
|Payload Officer (PLO)||In charge of cargo (including proper weight distribution) and weapon systems.|
|Life-Support Officer (LSO)||In charge of consumables, breathing mix, CELSS, toilets, et al. Also the Medic.|
The small spacecraft watchbill will have 3 eight-hour Watches staffed by Guidance, PLO and Chief in rotation. Neither the FCOM nor the LSO stand watches; the FCOM is too busy being in charge and the LSO is not qualified.
In Andre Norton's THE SARGASSO OF SPACE, a small Free Trader class starship has twelve crew members. Control Deck: Captain-Pilot, Astrogator (badge: Chart) second in command, Apprentice astrogator, Com-Tech (badge: Lightning bolt) communications officer. Engine Deck: Chief Engineer (badge: Cog wheel), two Engineers, Apprentice Engineer. Cargo Deck: Cargo Master, Cargo apprentice, Medic, Cook-Stewart. And of course the ship's cat.
In the game GURPS: Traveller Starships are the following rules for the size of spacecraft crews.
Robert Heinlein's Stranger In A Strange Land suggested these crew skills as a minimal list for an interplanetary exploration spacecraft:
- medical doctor
- ship's commander
- chemical engineer
- electronics engineer
- atomics engineer
- rocket engineer
In the novel the ship could only carry a maximum of eight crewmembers, so each person filled a minimum of three of these jobs, and most of them did four or more.
In Sir Arthur C. Clarke's 2010, they had these crew positions:
|Engineering-Propulsion||Captain Tatiana Orlova|
|Navigation-Astronomy||Dr Vasili Orlov|
|Engineering-Structures||Dr Maxim Brailovsky|
|Engineering-Communications||Dr Alexander Kovalev|
|Engineering-Control Systems||Dr Nikolai Ternovsky|
|Medical-Life-Support||Surgeon-Commander Katerina Rudenko|
|Medical-Nutrition||Dr Irma Yakunina|
The Young People's Science Encyclopedia, vol 17 Sp-Su, suggest these crew positions:
|Profession||Specialization||Primary Professional Responsibility||Organizational Responsibility|
|Pilot & Engineer||Mechanical & Nuclear||Overall vehicle systems, propulsion||Command of spacecraft|
|Pilot & Engineer||Electronics||Guidance, control, navigation on board electronic computer system||First deputy commander|
|Pilot & Engineer||Electrical & nuclear||All electrical systems, cable systems, converters, generators, auxiliary power supply||Second deputy commander|
|Pilot & Engineer||Nuclear||Propulsion specialist||Specialist|
|Pilot & Engineer||Mechanical||All mechanical subsystems||Specialist|
|Pilot & Engineer||Electronics||Instrumentation communications, robot systems||Specialist|
|Pilot & Physician||Medicine, Dentistry, Psychiatry, Radiology, Biology, Medical technology||Biotechnical life support systems, food and sanitary control, health and morale of crew||Medical officer|
|Profession||Specialization||Primary Professional Responsibility||Organizational Responsibility|
|Pilot & Engineer||Mechanical & Nuclear||Vehicle systems, all mechanical and electric subsystems and propulsion||Command of spacecraft|
|Pilot & Engineer||Electronics & Electrical||Guidance, control, navigation, all instrumentation and communication||First deputy commander|
|Pilot & Physician||Medicine, Radiology, Biology, Medical technology||Biotechnical subsystems of life support systems, food and sanitary control, health and comfort of crew||Medical officer|
There are some standard nick-names for various jobs (some of these are strictly military).
|Black Gang||Engine room crew (reference to shoveling coal)|
|X Bubbas||Generic term for group of officers. May apply to segment of the warfare community, or officers assigned to a specific location or command. (e.g., Orbital Warfare Bubbas, J9 Bubbas, etc.)|
|Chief Snake and his boy|
(aka Ratfink and Dob-in)
|Coxwain (in charge of ship's discipline and also steering the ship) and assistant|
|Cooky||Chief Mess Officer|
|Deck Apes||Boatswains mates, Flight deck crew, Aviation Boatswains Mates|
|Fuelies||Aviation Boatswain's Mate - Fueling|
|Guns, Gunner, Gunny||Gunnery officer, Gunner's Mates|
|Jack in the Dust||Baker|
|Knuckle dragger||Crewmember with more brawn than brain|
|Mess Cranks||Non-rated men assigned to assist in the galley|
|Nukes||Nuclear power techs|
|Sparks, Sparky||Radio officer or Electronics tech|
|Spooks||Intelligence, Electronic Warfare and Cryptography officers|
|Twidgets||Electronic Warfare officers|
|Wingnut||Crewmember of limited intelligence who is safer away from|
anything more hazardous than a pencil
|X Weenie||Generic Term. The "Intel Weenie" is the Intelligence Specialist|
|Zeros||Officers (used by enlisted men only)|
In the game SPI's Universe, there are some colorful names for various professions.
|Astroguard||Member of a planet's or star system's local military spacecraft force.|
|Star Sailor||Member of the federal spacecraft navy.|
|Freefaller||Soldier in the zero-gravity branch of the federal armed forces.|
|Ranger||Soldier in the standard ground branch of the federal armed forces.|
|Spacetrooper||Soldier in the assault force branch of the federal armed forces.|
|Scout||Member of the exploration branch of the federal armed forces.|
Tyge Sjostrand suggest the term Espatiers for space marines, since after all the term "marine" implies the ocean (French marine, from Latin marinus, derived from mare "sea"). The best guess I have at how it is pronounced is "Ess pa tee yea". Rick Robinson really likes Mr. Sjostrand suggestion:
Frederik Vezina disagrees about the pronunciation.
And in the anime Macross, the (Japanese) writers noted that the military on the ground is called the "Army" and the military on the ocean is called the "Navy", so logically the military in space would be called the "Spacy" (alternatively it could be a contraction of "Space Navy"). Since the release of Macross, the term has been used in other works: Martian Successor Nadesico, Voices of a Distant Star, and Mobile Suit Gundam.
Alas, "Spacy" is a little too similar to "Spacey", which in the slang of the United States means "vague and dreamy, as if under the influence of drugs".
Captain Christopher Thrash of the US 2d Armored Cavalry Regiment disagrees with the paragraphs above in yellow:
Traditionally, the areas of the craft closest to the control rooms is known as "officer country", while the greasy cabled and be-piped areas inhabited by sergeants and enlisted men is known as "below decks" (though which is below what becomes an open question in microgravity). Generally a 24 hour "day" will be divided into six 4-hour watches, Alpha, Beta, Gamma, Delta, Epsilon and Zeta.