# Search results

1. ### OHM Lagrange MFD

I've just run this scenario through ADSWNJ's Lagrange MFD for an arbitrary date and this is what I get for EML1: Day 0 0.007 km Day 1 0.048 km Day 2 0.093 km Day 3 0.033 km Day 4 0.176 km Day 5 0.445 km Day 6 0.706 km Day 7 1.105 km Day 8 1.994 km Day 9 3.654 km Day 10...
2. ### OHM Lagrange MFD

Thanks, 'Ajaja' Equation (10) gives the standard fifth-order polynomial for 'u' (to use the paper's notation). This polynomial equation is actually valid for both the circular and elliptic three-body theories of Lagrange points - although the paper deals with the former, and not the later...
3. ### OHM Lagrange MFD

Hi, 'Ajaja' What is the underlying physical theory of your Lagrange points MFD? Is it CR3BP or the ER3BP? ASDWNJ's Lagrange MFD is based on the latter. From experience, I know that if placed at L1 or L2 of the Earth-Moon system in Lagrange MFD, a vessel will noticeably drift off onto the...
4. ### Determining speed relative to surface (ground speed)

Hi, 'malcontent', to do the scaling, you need to set a scale for mass, distance and time. Suppose 'M' is the mass of the gravitating body (in your case, the Earth); 'T' is the orbital period; and 'R' is the radius of the much smaller secondary body (the Moon) from the primary body (the Earth)...
5. ### Determining speed relative to surface (ground speed)

Hi, 'malcontent' I've been following this thread off and on for the last few weeks. Here's an approach to your problem that you may want to consider. As I understand it, you have developed an integration engine that reproduces a normal Keplerian (i.e., circular, elliptical, parabolic or...
6. ### Building a simple ephemeris generating tool for short-run mission planning

In response to a request from 'dgatsoulis', here are some links to a short series on direct transfer from a (coplanar) Low Earth Orbit to Earth-Moon L2. Part 1: Part 2: Part 3:
7. ### Building a simple ephemeris generating tool for short-run mission planning

In response to a request posted on Youtube, here is a linked to Part 1 of a short video series demonstrating an off-plane transfer from the ISS to EML1. ---------- Post added at 09:41 AM ---------- Previous post was at 09:29 AM ---------- And, finally, Part 3: Enjoy.
8. ### A generalised ideal rocket equation

And here is a short video demonstrating the effectiveness of the maths set out earlier in this thread to determine the correct parameters for very low-thrust orbit insertion burns. A Shuttle A, with modified low thrust (9000 N) main engines, in a high eccentricity lunar approach orbit...
9. ### More on the ideal rocket equation

This post is a largely technical note that continues an exploration of the Ideal Rocket Equation in a perturbed Keplerian gravitational field. It is a continuation of an earlier post entitled "A Generalised Ideal Rocket Equation" in the Maths & Physics section of the Orbiter Forum. These notes...
10. ### SDK Question Matlab and Orbiter

Although I'm not trying to connect Matlab to Orbiter, I am trying to connect Mathematica to Orbiter. I have the web version of Orb::Connect installed and it works just fine in a browser. But I am trying to connect via lower level HTTP PUSH requests as per the Orb::Connect documentation. This...
11. ### A generalised ideal rocket equation

Enjo - note that I've added a small piece of code that solves Kepler's equation to find 'r' from BTC's initial estimate of the time before periapsis that the orbit insertion burn should start. Let me know if you have questions.
12. ### A generalised ideal rocket equation

Enjo, try 'kpgelling'. Thanks.
13. ### A generalised ideal rocket equation

Enjo Thanks. No spare time at the moment to tinker with this. I may have some Thursday/Friday. Regards
14. ### A generalised ideal rocket equation

Enjo Thanks. Sunday evening here in HK. I'll have a look at the code tomorrow and post comments. wrt licenses: I'm fine with anything you are fine with. ---------- Post added 11-07-16 at 02:59 AM ---------- Previous post was 11-06-16 at 12:20 PM ---------- No, not familiar with...
15. ### A generalised ideal rocket equation

Yes, and no. Not all Keplerian cleverness disappears with the introduction of perturbations. Out to the edge of the Earth's SOI at least, the Sun's gravitational contribution is effectively a small, tidal contribution. The real problem is one of time-scale: the spacecraft will spend a long...
16. ### A generalised ideal rocket equation

Actually, I've given no thought to how fast modern CPUs execute. Generally, I presume them to be fast enough for current purposes. The issue is: "What is the best available first guess?". At the outset, the best available first guess is the value calculated by the current BTC algorithm...
17. ### A generalised ideal rocket equation

Yes, it is a process of refinement. The underlying process for finding the burn start time and duration is an iterative one. This means that given a first 'best guess', the algorithm provides a better guess; and then, based on than new, 'best guess' it calculates an even better guess. And so...
18. ### A generalised ideal rocket equation

OK, Jedidia I assume you mean going somewhat beyond low-thrust orbit insertion - say Earth to Mars transit? And when you say low thrust, can you give an example of thrust characteristics - i.e., m_0 - mass of spacecraft; gam - mass flow-rate of craft ve - effective exhaust...
19. ### A generalised ideal rocket equation

Enjo Please note that I have amended the code of the post time-stamped 11-02-16 04:39 AM to fix two minor things: 1. a lingering reference to 'a' which should have been 'SMAJ'; and 2. the calculation of the 'tbp' - time before periapsis. Previously, it was correct only for elliptical...
20. ### A generalised ideal rocket equation

Enjo Here (below) is a revised version of the code that includes the two-variable root-finding solution. This code is valid for a wide range of spacecraft with widely varying thrust characteristics approaching periapsis on an elliptical or hyperbolic trajectory and wishing to enter a circular...