Tangent Zero logo Online Rocket Calculator

Here are some basic rocket science tools that I used to help make Tactical Command. Some of the FTL stuff is based on space craft using a Heim-Drosher constant acceleration drive.

Time, Distance, and Velocity for Constant Acceleration
How to use:

Velocity and acceleration is most often used to determine the time and distance needed to reach translation velocity or decelerate from FTL exit to a dead stop.

Duration and acceleration is handy for determining the max radius of an intercept sphere or how fast you're travelling when a timed event happens.

Distance and acceleration is used to calculate flight times for fly-bys or intercepts. If you need the time for a flight from station to station, divide the total distance by two, calculate, and then double the time. This models acceleration, turn over, and deceleration.

  Meters/Second   Hexes/Round   Lightspeed
  Meters/Second   Hexes/Round
  Seconds   Minutes   Rounds   Days Minutes in one round
  Meters   Kilometers   Hexes   AU Kilometers in one hex
Given Velocity and Acceleration Duration and Distance
Given Duration and Acceleration Velocity and Distance
Given Distance and Acceleration Duration and Velocity

Orbital Velocity and Period Calculator
How to use:

What is orbital velocity and period? Orbital velocity is the exact speed required to maintain a stable circular orbit around a planet or moon. Period represents the time it takes to complete one orbit.

Orbital velocity is the direct result of planetary mass and altitude above the surface (in kilometers.) This utility assumes that all stoney planets and moons have a density of 5,520 milligrams per cubic centimeter (Earth density.) Other density values and planetary data are listed in the side bar.

Round duration and hex size are pulled from the previous section.

Planetary Radius (km)             Name Radius Density
Altitude (km) Mercury 2,440 5,430
Density (mg/cm3) Venus 6,052 5,200
Earth 6,378 5,520
Period (seconds) Luna 1,738 3,340
Velocity (m/s) Mars 3,390 3,930
Surface Gravity (m/s) Jupiter 69,911 1,330
Orbital Gravity* (m/s) Saturn 58,232 687
Combat Rounds per orbit Uranus 25,362 1,320
Orbit Size (hex ring) Neptune 24,624 1,640
OV as Hexes/Round Pluto 1,137 2,050

* While in a stable orbit, there is only the illusion of zero gravity. Gravity is still present, but it is precisely blanced by orbital velocity.

The default radius and density is that of Earth. An altitude of 274.6 km was chosen as a default since it generates handy orbits with a period of 90 minutes. This is a good baseline for most tactical combat scenarios.

Orbit Size reflects a ring of hexagons starting at the center of the planet or moon and radiating outwards. OV (orbital velocity) states how many hexes per round an object in that ring will move each combat round.

Relativistic Kill Vehicles
How to use:

RKVs can take many forms; long range missiles, big rocks with a bad attitude, or suicidal spacecraft. In general terms, the only two significant factors are the mass and velocity of the projectiles. How much of that potential energy is actually transferred to the target is subject to a lot of variables that are beyond the scope of this utility.

Mass is measured in metric tons. That's one thousand kilograms per ton. Velocity is determined as a fraction of the speed of light. While this kind of velocity is usually not built up during ship to ship combat, it is possible that a strategic relativistic attack could reach these speeds. Typical values would be like .25 or 25 percent of the speed of light.

Mass of Projecticle (t)
Velocity (psol)

Joules of Energy

Planet cracking is not an exact science. While brute force such as Chicxulub will surely get the job done. I've heard some people mention that as little as 1,000 individual one gigaton strikes on major population centers would be sufficent to destroy a civilization, wreak the biosphere, and send the natives that do survive back to the stone age. On the bright side, that implies that even at the height of the Cold War we couldn't have wiped out humanity with nuclear weapons.

Yield Description
.002 kt  Murrah Building, Oklahoma
(April 19, 1995)
1.0 kt   a 4.0 earthquake on the Richter scale
3.9 kt   Dresdan (Febuary 13-15, 1945)
15.0 kt   Hiroshima (August 6, 1945)
22.0 kt   Nagasaki (August 9, 1945)
1.0 mt   a 6.0 earthquake on the Richter scale
1.2 mt   B83 (largest nuke in US active service)
2.5 mt   Meteor Crater, Arizona
(estimates vary up to 20 mt)
9.0 mt   B53 (larget US warhead, not in service)
15.0 mt   Tunguska event (estimates up to 40 mt)
24.0 mt   Mt. Saint Helens (May 18, 1980)
25.0 mt   B41 (largest US bomb, not in service)
50.0 mt   Tsar Bomba (October 30, 1961 -
largest USSR device)
150.0 mt   Krakatoa (August 27,1883 -
estimates vary up to 200 mt)
600.0 mt   Thera (Santorini, Greece)
1.0 gt   an 8.0 earthquake on the Richter scale
6,000.0 gt   Shoemaker-Levy 9 (18 July, 1994)
100,000.0 gt   Chicxulub impact (extinction event)

Travel Time and Translaction Velocities
How to use:

Using Heim Quantum Theory as a basis for faster than light (FTL) travel, a ship needs to reach translation velocity before it can engage the second stage drive. The mininum velocity for this drive is 30,000 m/s. Technically, that threshold is not FTL. At that velocity, the second stage speed is equivalent to 10% of light speed. The mininum velocity for true FTL is 300,000 or more meters per second.

The first function determines what your second stage speed will be based on your translation velocity. The second function creates a table that determines the time required to run up to run to speed, translated to FTL, and then exit and possibly decelerate. For ease of use, one G is equal to 10 meters per second.

Velocity (m/s)   = Lightspeed (C)
Drive Rating (G)   Target Distance (ly)  

Travel times are based on the need to make a 'run' up to translation velocity, move FTL to the destination, and optionally decelerate. By selecting the optimal percentage of the speed of light, you can determine the shortest flight time based on the drive rating of the ship. FTL is in multiples of C. Acceleration / deceleration and FTL times are measured in days. Fly By Time is acceleration plus FTL travel times with no deceleration phase. Round Trip is acceleration plus FTL plus deceleration times.

Guidelines for a Space Propulsion Device Based on Heim's Quantum Theory, Walter Dröscher1,
Jochem Häuser, AIAA Paper 2004-3700, July 11, 2004

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