I am using the MATLAB exchange file called "A MATLAB Script for Earth-to-Mars Mission Design", getting error sunscreen is not defined

Hello all

I am using the MATLAB exchnange file for the Earth to Mars mission design, the file called

"A MATLAB Script for Earth-to-Mars Mission Design

Version 1.4.0.0 (106 KB) by David Eagle

Determines optimal n-body ballistic trajectories from Earth park orbit to encounter at Mars."

When I am trying to run e2m_matlab.m code, I am getting some error, like following

Unrecognized function or variable 'sunscreen'.
Error in e2m_matlab (line 223)
sunscreen on;
^^^^^^^^^^^^^

Solve the problem I defined the sunscreen function in the matlab, then I was not throwing out the sunscreen error but, afterward I am geeting the following error regarding snopt

Sunscreen is now enabled.
File: snopt.m Line: 3 Column: 20
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

Error in e2m_matlab (line 225)
   [x, ~, ~, ~, ~] = snopt(xg, xlwr, xupr, xmul1, xstate1, ...
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Any help will be greatly appreciated!

Thank you in advance for your help.

Best regards

Chintan Prajapati

[Walter Roberson]

I find reference that snscreen (the name used in the File Exchange code) is part of SNOPT .

Unfortunately I am not able to find any distribution of SNOPT, including not finding any definition of snopt.m

[Chintan]

Thank you very much for your response.

Best regards

Chintan Prajapati

[dpb]

What about at the <UCSD link provided in the FEX "Requires" secton>? I didn't try downloading anything, but it indicates SNOPT Fortran/Matlab stuff is available...

[Walter Roberson]

Ah, I overlooked that part!

[Chintan]

Thank you dpb for your help.

Answer 1

[Sam Chak]

Hi @Chintan

Most of the simulation projects by David Eagle require SNOPT, which stands for Sparse Nonlinear OPTimizer. If you are a student or researcher based at a U.S. university, you can request access to unrestricted precompiled libraries for SNOPT. These libraries are time-limited to three months. However, you need to use your official university email (.edu) when requesting the libraries.

https://ccom.ucsd.edu/~optimizers/solvers/snopt/

Fortunately, David Eagle also provides the non-SNOPT version for some projects that use the optimizer from the Optimization Toolbox (OTB). You can download this version:

https://www.mathworks.com/matlabcentral/fileexchange/73646-a-matlab-script-for-earth-to-mars-mission-design-otb

[Chintan]

Hello Sam

I really appreciate your help.

Thank you so much.

Best

Chintan

[Sam Chak]

You're welcome, @Chintan. If you find the info helpful, please consider clicking 'Accept' ✔ on the answer to close the issue. You may post a new question to ask technical aspects of the Earth-to-Mars mission design.

[Chintan]

Thank you for letting me know. I didn't know about how to close the answer, but now I know, so I will do it right away.

Thank you