Lunar landing energy

Compute the mass and time required to land as a function of initial altitude, given spacecraft propulsion parameters thrust and specific impulse.

See also Constant, Plot2D, Energy

%--------------------------------------------------------------------------
%   Copyright (c) 2015 Princeton Satellite Systems, Inc.
%   All rights reserved.
%--------------------------------------------------------------------------
%   Since 2016.1
%--------------------------------------------------------------------------

% Constants
mu          = Constant('mu moon');
rMoon       = Constant('equatorial radius moon'); % km

% spacecraft parameters
m0          = 200; % kg
thrust      = 220; % N
Isp         = 320; % s
uE          = Isp*9.806; % m/s

% orbital parameters
h           = linspace(0,30000); % Initial altitude, km
r           = rMoon + h;

% compute the energy difference
e           = m0*(mu/rMoon + Energy(r,mu))*1e6;
tau         = e/(0.5*thrust*uE);
mF          = tau*thrust/uE;

yL          = {'Duration (s)' 'Mass Fuel (kg)'};

Plot2D(h,[tau;mF],'Altitude (km)',yL,'Lunar Landing Energy');
subplot(2,1,1)
text(0.5*sum(xlim),0.5*sum(ylim),...
  sprintf('m0: %g kg\nthrust: %g N\nIsp: %g s',m0,thrust,Isp))


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% PSS internal file version information
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% $Id: 1a32245eb43728b6766a8ddfcfc91b15fc09f7d2 $

Published with MATLAB® R2024a