SysML is a modeling language, similar to UML, that some organizations use for Systems Engineering http://sysml.org
Model Based Systems Engineering (MBSE) is the general term for modeling systems (for example with SysML) and then applying computer analysis tools to those models to perform Systems Engineering optimizations.
Google Project Ara made use of MetaMorph Software Tools to help module designers perform PCB layout, component integration, module pricing estimation, package fit check, module performance, and specification compliance. See http://www.metamorphsoftware.com and https://webgme.org
In general, there is a lot of opportunity to modernize MBSE tools and bring them to a wider audience.
Modelica (https://www.modelica.org) is another useful option for MBSE that has more commercial front-ends than one can shake a stick at (e.g., CATIA and Wolfram SystemModeler), as well as free options.
OpenMDAO is very much an option, though it is geared more for model-based analysis and numerical optimization for highly integrated systems. The primary use case is to assist in early conceptual design, particularly for vehicles. But basically, it's a Python framework for passing variables, functions, and derivatives of functions around between disparate codes.
In practice, the most common systems engineering tools that I've seen are actually excel and powerpoint. Not knocking either of those tools (or the role of systems engineer), but that seems to be the current state of the field.
For smaller projects (say, what an engineer might run and manage by themselves), there's always Microsoft Project. That's the lower level default for making/managing schedules.
For much larger projects, or projects of projects (think large engineering systems of systems that take years to design/build/test/deploy), there's all kinds of software available. My company uses Oracle Primavera for this sort of thing.
Also, don't forget Excel. Excel is everywhere and used for all sorts of things it probably shouldn't be used for.
The civil engineering department at my university doesn't have any dedicated programming or numerical analysis course. So, they're taught to use Excel. I took a structural dynamics grad course from them and the instructor explained how to do an explicit ODE solution using Excel. I was horrified. I just asked if I could use Matlab and the prof said yes. The prof just used Excel because that's all the undergrads (and therefore the new grad students) knew.
A key reason Excel is the default is that people have access to it, while Matlab is prohibitively expensive.
One way to break that trend is to choose GNU Octave, the open source alternative to Matlab. The more widely GNU Octave gets used (or similar free tools) the more likely we are to move beyond an Excel by default engineering culture. GNU Octave covers a large percentage of Matlab features and is able to run Matlab code. https://www.gnu.org/software/octave/
There are other tools, like SageMath, that are built on Python and may make an even better Excel alternative for organization that aren't dependent on legacy libraries of Matlab code.
I'm a systems design engineer so there was no way I'd use Excel for ODE solving unless I had no other choice. Matlab and Maple are the two languages I know best, but I'd also consider Fortran, Octave, Python, or Scilab for something like that, with C++ probably last (C++ for numerics is a pain since you have to convert between different packages for basic types like matrices and vectors). I'd probably also consider Julia, but I'm not that familiar with it yet. I had hopes for Fortress, but that died a quick death.
I've been a part of the SymPy team for several years including mentoring GSoC for two of those years.
The problem with SageMath is that you still have to convince people who are familiar with Excel to learn a new environment. Part of the reason why Excel is taught to the undergrads in that civil engineering program is that they use it in their co-op jobs. It becomes a self-perpetuating cycle since they don't learn any alternative as students so they go with what they know in their jobs.
In the handbook, Figure 2.0‐1 "SE in context of overall project management" shows the relationship between systems engineering and project management. While some SE responsibilities overlap with those of project management, the larger set of responsibilities focus on technical work. Microsoft Project isn't intended to be used to define requirements, perform technical trade studies, model and compare alternative system architectures, or configuration manage technical artifacts of the engineering process.
Hope that helps to clarify my prior comment. Happy to discuss more.
> Microsoft Project isn't intended to be used to define requirements, perform technical trade studies, model and compare alternative system architectures, or configuration manage technical artifacts of the engineering process.
I never meant to imply that Microsoft Project is a suitable tool for aiding in any of these things. Anyone crazy enough to try...
But if you want to make a Gantt chart, Project does well enough. The NASA systems engineers I knew certainly used Project for that purpose. Thus I hardly think you can say that it "isn't suitable for systems engineering" as it is useful in creating/viewing/editing one of the key tools of a system engineer's work -- a project schedule.