Hi, I found some acronyms/abbreviations in this post. This is how they expand:
| Acronym | Explanation |
| ESA | European Space Agency |
| Isp | Specific impulse (as discussed by Scott Manley](https://www.youtube.com/watch?v=nnisTeYLLgs), and detailed by [David Mee |
| perihelion | Lowest point in an elliptical orbit around the Sun (when the orbiter is fastest) |