StarTravelTM ($45.00) New! Program Description AeroRocket starship design using matter/anti-matter drive Copyright © 1999-2009 John Cipolla/AeroRocket Purchase What is StarTravel StarTravel performs two-body astrodynamics analyses of spacecraft and satellites knowing burnout velocity and flight-path angle at burnout. For this purpose StarTravel uses two-body astrodynamics for determining sub-orbital, orbital and interplanetary motion around the Earth and Sun. In addition, StarTravel performs general heliocentric and Hohmann Transfer orbital analyses for determining minimum velocity and flight time required for travel from Earth to other planets in the solar system. StarTravel also has a Solar System Calculator for animating orbital motion of the planets around the Sun. Finally, StarTravel uses the Special Theory of Relativity to determine elapsed time on Earth and aboard our starship when speeds approach the speed of light and determines the relativistic Doppler frequency shift of star light observed by our starship in the form of a color contour plot of the firmament.

StarTravel^TM Features
Circular, Elliptical and Parabolic/Hyperbolic Orbital Analysis
1) Plot Sub-orbital, orbital and escape trajectories around planets in the solar system knowing Burnout velocity (Vbo) and Flight-path angle at burnout (f).
2) Determine distance traveled from liftoff to impact (X) along planet curvature and sub-orbital flight path knowing Maximum altitude at burnout (Hb) and Down range distance at burnout (Xb).
3) Free flight angle from liftoff to impact (y), Sub-orbital flight time or orbital period (T), Planetary orbital velocity (Vcs), Planetary escape velocity (Ve) and Solar system escape velocity (Vsun) are all displayed in red for easy review.
4) Zoom-in to see near-planet trajectories for parabolic (e=1) and hyperbolic (e>1) flights when burnout velocity (Vbo) and flight path angle (f) are specified.
5) Determine velocity at origin planet sphere of influence (V₀₀) and Flight time from burnout to destination orbit (T) for parabolic and hyperbolic trajectories (e>1).
6) View detailed instructions, StarTravelManual.pdf, by clicking D’Click for Instructions on the main screen.

Heliocentric and Hohmann Orbital Transfer Analysis
7) Determine minimum energy (i.e. velocity) required for heliocentric and Hohmann transfer orbits from Earth to other planets in the solar system and the Moon.
8) Determine velocity change from liftoff to burnout (dV) required for orbital insertion into heliocentric orbits and Hohmann Transfers to the planets and the Moon.
9) Predict spacecraft velocity of approach with destination planet while on the transfer ellipse.
10) Predict time of flight from burnout in Earth orbit to interception of destination planet.
11) Specify miss distance for the computation of heliocentric dV and time of flight.
12) Solar System Calculator displays current position of the planets, distance from Earth to the planets and orbital periods of the planets in the solar system.

Relativistic Star Travel Analysis
13) Determine Earth elapsed time and star ship elapsed time (proper time) for relativistic star travel (0.3c < V < 1.0c).
14) Determine starship Mass Ratio requirements as a function of relativistic speed and exhaust velocity.
15) Display Doppler color shift on forward and aft star light as viewed from the starship.
16) Use one of three acceleration-velocity profile options for travel to the stars:
a) Constant velocity (G = 0, V = constant).
b) Constant acceleration (G = constant, Vmax = speed of light (c) if distance is great enough). ^{See note below.}
c) Constant acceleration then constant velocity coast (G = constant, Vmax = constant).

Note: Constant velocity and constant acceleration, Options (a) and (b) are not practical for realistic star travel. For example, unbounded acceleration at modest G-loading will rapidly allow a starship to approach the speed of light (at 1G acceleration a starship will attain the speed of light within 1 year proper time). As a starship approaches the speed of light infinite energy and therefore infinite Mass Ratio (MR) is required. Instead, the method of accelerating to a modest coast velocity, Option (c) is the preferred method, making star travel feasible within the lifetime of a human being at moderate acceleration (0.1G’s to 1.0G’s) and modest maximum velocity (0.1c to 0.5c).

Summary of Basic StarTravel^TM Features


Sub-orbital, Orbital and Escape Trajectory Analyses Back
As illustrated in Figure-1 trajectories around a massive object like the Earth, Mars and the Moon follow one of a family of curves called conic sections. Depending on the specific energy (E), angular momentum (h) and mass (G*M) of a body the eccentricity (e) of an orbit  will determine if the transfer orbit is a circle (e=0), ellipse (e<1), parabola (e=1) or hyperbola (e>1). The orbital elements of a body including the eccentricity (e) of an orbit are determined by burnout velocity (Vbo), flight path angle at burnout (f), burnout altitude (Hb) and down range distance (Xb) of an object for a two-body astrodynamic analysis. Because there is not enough space here to fully detail the orbital mechanics used in StarTravel please refer to the reference list in the included instructions (StarTravelManual.pdf).

Figure-1, Conic sections defined by eccentricity (e) and the other orbital elements.

To perform sub-orbital, orbital and escape trajectory analyses click Suborbital, orbital and escape trajectory under Trajectory Selections in the top toolbar. The input data for a sub-orbital trajectory and the resulting plot of the trajectory are illustrated below. This analysis includes the ability to determine time of flight (T) for sub-orbital and orbital flights (e<1). For hyperbolic and parabolic interplanetary flights (e=1 or e >1) the Flight time from burnout to destination orbit (T) represents the flight time in days or years to intersect the orbit of the planet selected using the Destination Planet orbit pull-down menu.


Figure-2, Example of sub-orbital flight.


Heliocentric and Hohmann Transfer Analyses Back
Transfer orbits from Earth to most of the planets in the solar system may be considered to be elliptical and co-planar. For example, a Hohmann Transfer between Earth and Mars may be achieved when the elliptical transfer orbit is tangent to Earth’s orbit at departure (v1=0 deg) and tangent to Mars orbit at arrival (v2=180 deg). This kind of interplanetary transfer orbit is called a Hohmann Transfer and represents the minimum delta-velocity (dV) required for Mars orbital insertion from Earth orbit. Other heliocentric (around the Sun) orbits to Mars and the other planets are possible if the transfer orbit intersects both the origin planet orbit and the destination planet orbit.

For example, when traveling from Earth to Mars the following Hohmann Transfer is possible. SpaceTravel results for Time of flight from burnout to intercept to Mars from Earth is 258.93 days with an Orbital Velocity around the Sun at burnout of 32.729 km/sec and dV for transfer orbit insertion is 2.945 km/sec for orbital insertion. Please see page 365 of Fundamentals of Astrodynamics or Table-1 for similar results from that reference.


Figure-3, Example of Hohmann transfer from Earth to Mars.


Solar System Calculator Back
The Solar System Calculator animates the orbital motion of the planets around the Sun. By checking the Solar System check box a present-day display of the solar system appears in the plot area to the right. Positions of the planets in the solar system as of the date and time displayed in green appears in the orbital plot. By specifying the desired time in the Maximum time from present input box the user can animate motion of the planets around the Sun. Also, by clicking the STOP command button the user can “freeze” the planet positions prior to reaching the maximum time specified. Finally, the ZOOM slider bar is used to zoom-in and zoom-out of the solar system plot.


Figure-4, Solar System calculations.


Relativistic Interstellar Travel Analysis- Star Travel near the speed of light (C) Back
It is impossible to exceed the speed of light because as an object approaches the speed of light the inertial mass of an object and therefore its mass approach infinity. It would take infinite power to accelerate an object beyond the Einstein limit (C) or “light barrier”. However, because of time dilation as predicted by Einstein's theory of Relativity, an astronaut can travel stellar distances, that is many light years (ly) within his/her own life time while many thousands of years will have elapsed on the planet of departure or Earth in our case.

For example, if a starship leaves the vicinity of Earth with a constant acceleration of 0.999998G’s toward a star located 1000 ly (light-years) from Earth. Determine (a) the elapsed time on Earth when the starship reaches the star and (b) the proper time on the ship, relative to Earth clocks. From the Relativistic Interstellar Travel screen the results are: a) Elapsed time on Earth during the flight is 1002.65 years. b) Elapsed time on the starship (proper time) during the flight is 13.46 years.


Figure-5 Relativistic Time Dilation  and Doppler light shift analysis showing FWD (forward) star colors.


MODIFICATIONS AND REVISIONS
StarTravel 3.0.0.6 Modifications
1) For the Heliocentric and Hohmann Transfer Analyses and the Solar System Calculator the central Sun image has been replaced by a realistic image of the Sun.

StarTravel 3.0.0.5 Modifications
1) During a Solar System animation each planet's starting point location in orbit is marked by a hollow white circle.
2) After each Solar System animation the option, Planetary-plots appears. This option allows the X-Y plot of Planet velocity vs. true anomaly, Planet velocity vs. elapsed time, Angular momentum (h) vs. true anomaly and Angular momentum (h) vs. elapsed time. Where, angular momentum, h = 2 dA/dT is constant for each planet's orbit in agreement with Kepler's second law of planetary motion. Kepler's second law states "The line joining the planet to the sun sweeps out equal areas in equal times" or another words, dA/dT = constant.
3) Fixed the plot position error for the dwarf planet Pluto which becomes appreciable for elapsed time approaching 100 years. For purchasers of StarTravel 3.0 please contact AeroRocket to receive your FREE upgrade to the new version which fixes this error.

StarTravel 3.0.0.1 Modifications
1) The Solar System Calculator now uses an iterative solution based on Kepler's second law that states "The line joining the planet to the sun sweeps out equal areas in equal times" to compute planetary positions verses time.
2) Easily reset the Solar System Calculator to its initial starting screen by clicking the T=0 command button.
3) New version 3 screen images included in the detailed instructions, StarTravelManual.pdf.

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