[Space, Spaceships] Mars Semi-Cycler?

[AlexanderHowl]

~$700M is not a lot for a spacecraft, and it has the advantage that is large enough to provide 0.5g, so you can provide transportation for normal unaugmented humans without difficulty, but it is your choice. However, the design that I gave would have a crew of 125 (20 control, 80 technicians, and 25 support), so the vast majority of the people would be NPCs. In that case, I would suggest that the PCs be officers, similar to Star Trek, though the majority of officers would be NPCs.

One of the issues with any realistic design is economics (which can be waived in the case of space opera). Now, one advantage of a cycler over a magsail design is that it is really cheap per ton moved (the cycler costs 1/15th as much per ton moved), though this is somewhat balanced by the fact that they take five times long to travel (and they require connections to magsails). I would say that they cost 50% to move cargo and passengers as a magsail design, so there is a place for them economically.

[DaltonS]

I suppose one of my problems is that I have trouble with the idea of a spacecraft as a commercial vessel. Commercial space travel (and by that I mean moving people for money) may be very close but as yet it is still a future thing. The first customers will probably be governments anyway, and if they see it making a profit they'll try to take it over and ruin it in the process. Government run missions are still feasible if you can convince the PTBs that it might be politically profitable for them, but then they will insist on having some input to the mission design process (which frankly scares me a bit). Now I be overreacting to having re-read "2001: A Space Odyssey" recently but until I see some serious advertisements for tickets on a spacecraft at affordable prices I will regard the whole topic as "maybe someday" speculation.

At the moment my spacecraft design is mission oriented with cost something to be considered by the bean counters back home. And in this case the "mission" is primarily political; settle Mars. The tools might not be absolutely efficient but they will (hopefully) look good to the people whose support the politicians want. Sorry to be such a downer, but we are living in a political time and politics seems to be all I hear about on the news any more. :(

Dalton “So let's pretend we can actually do this” Spence

[Anthony]

Originally Posted by DaltonS

I suppose one of my problems is that I have trouble with the idea of a spacecraft as a commercial vessel.

It's package delivery. If there's actually reason to move cargoes, and the number of people doing it is large enough that they don't all want to do vertical integration and have their own vessels, there's room for a business.

Now, it's a boring business that isn't terribly gameable (realistic spaceship crews have essentially zero ability to make decisions about their path), but that's a separate problem.

[AlexanderHowl]

Yes, there is not a lot of choice with realistic settings, as delta-v is a harsh mistress. As for commercial applications, it is mostly orbital manufacturing, the mining of rare metals, orbital solar, and nitrogen harvesting. For example, it is probably going to be impossible to produce TL10+ physical technology without zero-g manufactoring and orbital vacuum manufacturing (the flaws caused by gravity and by laboratory vacuum manufacturing will likely limit terrestrial manufacturing to TL9-).

[DaltonS]

Okay, I'm going to indulge in a little "equine necromancy" here. I've recently been trying to map my Martian “Gas” Station which got me to thinking about the other threads I posted here involving my "Domed Mars" setting. Having decided to use Mag-Sails instead VASMIR drives in both the Semi-Cycler and Trans-Orbital Taxi to reduce the magsail "burn times" to something manageable (6 and 10.8 days respectively, although when the reaction mass in the Taxi's collapsible tanks is expended when launching from Mars the reduced LWT makes the magsail boost time 6.5 days) I decided to tweak the spreadsheets for both. According to my calculations a SM+9 Semi-Cycler would need 5.77 PPh to deploy its magsail. I upgraded the energy banks to 5PPh which would take 15 hours to fully charge using the reduced small reactor (⅓ PP). While this is slightly less than required, deploying the magsail would only drain the energy banks at 1PPh per hour giving the reactor plenty of time to make up the difference (138.6 minutes out of 5 hours to be exact). Here are the revised stats.

PERDUE REDUX (PERDUE-CLASS MEDIUM INTERPLANETARY TRANSPORT)

TL      Name      dST/dHP  Hnd/SR  HT         Move          LWt.      Load     SM      Occ      dDR  Range   Cost   
9^  Perdue Redux    100     -5/4   13  0.001G/375 mps [1]  3,000  1,404.2 [3]  +9  34ASV [4,5]   15    —    $69.5M

Length: 70 yd. (210 ft.) Crush Depth: 32.5 Atmospheres (1,071 ft.)
Power Points: +⅓ / -0
Energy Bank: 5 PPh / 900 PPt
Space Performance: Hnd/SR: -5/4 sAccel: 0.001Gs/375 mps

SHIP SYSTEMS

 FRONT   
[1]      Metallic Laminate Armor
           dDR 15
[2-4]    Hangar Bay
           Cap.: 300 Tons / SM+6 / Launch: 100 Tons/min
[5]      Magsail Sail
           0.001 Gs / 375 mps [1,2,7]
[6]      External Clamp
           3,000 Tons
[Core]   Smaller SM Systems
           SM+8
  [a]    Control Room
           Comp: C6 / Comm/Sensor: 6 / 4 Stations
  [b-c]  Habitat
           two bunkrooms, two cabins, one rec room
           one fabricator minifac, eight hibernation chambers, one lab, one sickbay

 CENTER  
[1]      Metallic Laminate Armor
           dDR 15
[2-3]    Vehicle Dock
           300 Ton Capacity / SM+7 [6]
[4]      Engine Room
           1 Control Station / 2 Workspaces
[5-6]    Vehicle Dock
           300 Ton Capacity / SM+7 [6]
[Core]   Habitat
           one hydroponics bay, two bunkrooms, seven passenger cabins, 50 tons of steerage cargo

  REAR   
[1]      Metallic Laminate Armor
           dDR 15
[2]      Smaller SM Systems
           SM+8
  [a†]   Fission Reactor
           1 Power Point / 50 yr Fuel [8]
  [b-c]  Battery Bank
           2 PPh / 360 PPt / 2 PP
[3]      Battery Bank
           3 PPh / 540 PPt / 3 PP
[4-6]    Cargo Hold
           450 Tons / SM+5 Bay Doors

User Notes: The modular Vehicle Docks can hold two SM+7 (300-ton) auxiliary craft, usually atmospheric craft used as orbital taxis. (Modularity allows the customized docks to be swapped in and out as required.) If an auxiliary craft has habitat modules installed, the crew usually stays aboard their ship to stretch life support; otherwise they travel as passengers or in hibernation chambers.
Design Switches, Features, & Notes: 5 Airlocks (Capacity: 5 people each), Auxiliary Craft Cost: $44,448,120; Standard Food Cost: $50,000; Total Cost: $113,998,120
IR SIGNATURE: +17 (+4 Energy Bank, +6 Fission Reactor, +7 Magsail)
CAMPAIGN OPTIONS: Exposed Radiators [2], EBS's Unofficial rules
[1] Accel assumes Luminosity 1.0 Star at 1.0 AU
[2] Counts as Exposed System when deployed (see p. SS1:66), Targeted at SM+12, Radiators are targeted at SM+9 if central hull is facing attackers, SM+4 otherwise
[3] Load includes: 4.2 tons of Crew & Passengers, 50 tons of Standard Food, (25,000 man-days / 735 days), 450 tons in Cargo Hold, 600 tons in Vehicle Dock capacity, 300 tons in Hangar Bay
[4] Plus 8 in Hibernation Chambers, [5] Crew Requirement (17 total): 4 Control Stations (1 Captain/Pilot, 1 Operations Officer, 1 Chief Engineer,
1 Navigator/Comm/Sensor Operator), 1 Technician, 6 Auxiliary Craft Crew, 2 Passenger Care, 1 Entertainment, 1 Medical, 1 Scientist, 1 Gardeners
SYSTEM NOTES: [6] Modular, [7] Uses 1 Power Point to activate, then consumes no power
FUEL USED: [8] Fissionables
RADIATION PROTECTION FACTOR (PF): 210/420/210, Non-Mass Shielded PF: 70 (see p. SS5:41)

AUXILIARY CRAFT

Qty.                 Ship                 Location     Cost    Mass  Crew  
   1  Aurora-Class OTV                    Front     $811.6k    30    1     
   1  Condor Spaceplane                   Front     $8.89M     100   2     
   1  Kobold Work Bug                     Front     $1.12662M  30    2     
   1  Midnight Sun-Class Orbital Shuttle  Front     $1.468M    100   2     
   1  Sling Liner Passenger Barge         Front     $216k      30    1     
   2  Mars Trans-Orbital Taxi (M)         Center    $31.9359M  600   8

HABITATS

Qty.   Location           Type          SM         Notes         
   2  Front [Cb]  Bunkrooms             +0             8 person
   2  Front [Cb]  Cabins                +0             4 person
   1  Front [Cb]  Rec Room              +0  20 patrons, 2 staff
   1  Front [Cc]  Fabricator Minifac    +0         $500 per Hr.
   8  Front [Cc]  Hibernation Chambers  +0           8 chambers
   1  Front [Cc]  Lab                   +0   2 person, +1 Skill
   1  Front [Cc]  Sickbay               +0      1 bed; +2 Skill
   1  Center [C]  Hydroponics Bay       +0  4 person production
   2  Center [C]  Bunkrooms             +0             8 person
   7  Center [C]  Passenger Cabins      +0            14 person
  10  Center [C]  Steerage Cargo        +0              50 tons

Created using the GURPS Spaceships Design Spreadsheet Version 2.0 RC 33 copyright © 2009-2017 Eric B. Smith. This spreadsheet is based on information contained in the GURPS Spaceships series of books.

Dalton “who will post the new Trans-Orbital Taxi stats later” Spence