Great work Seven perforce.

Great graph. Could you also add the direct delta-V's from LEO to LLO, instead of having to pass through the EML-1 and EML-2 tollbooths? The 100 km LEO orbit is not used by anyone to get to anywhere as it is too unstable. I think you can delete that from your graph. The descriptions for the orbits seems to be quite far from their respective marks. Could you move the descriptions next to their marks? The Earth Hill Radius Could be replaced with Mars, as that is a more useful destination.

First of all, launch providers quoting a payload to LEO are going to invariably quote the maximum possible payload they could loft into any orbit, so they will typically use a 100x100km orbit as a standard reference.

Second, this altitude isn't used for extended parking, but it can be used as a precursor to a transfer when you want to change the longitude of your Hohmann transfer semimajor axis.

It is also useful for planning re-entry; the apogee burn to lower your perigee to 100 km is roughly what you need to ensure proper re-entry angle, so you want 100 km as a reference from any orbit.

Computing dV directly from LEO to LLO would be a solution to the three-body problem, and would depend quite heavily on the route you wanted to take.

I'm also pretty sure that such an orbit would be more expensive from a dV perspective than going through either EML1 or EML2.

Giving Mars as the highest destination would be a four-body problem, which is even worse than a three-body problem.

QuoteSecond, this altitude isn't used for extended parking, but it can be used as a precursor to a transfer when you want to change the longitude of your Hohmann transfer semimajor axis.I've never seen a launch that goes that low before transfer. Its normally around 200 km.

Are you sure that was 98 statute miles? That seems really low. My bet is 98 nautical miles, i.e., 176 km.

Apollo used to insert into a short-term LEO parking orbits of between 100 and 110 statute miles, circular. (It was higher for earlier flights; the J missions, to keep as much delta-V for TLI as possible, inserted into the lowest possible orbit, usually targeted for about 98 statute miles circular.) This amounts to, what, around 130 km?Definitely lower than 200 km...

Quote from: sevenperforce on 04/01/2016 02:42 pmFirst of all, launch providers quoting a payload to LEO are going to invariably quote the maximum possible payload they could loft into any orbit, so they will typically use a 100x100km orbit as a standard reference.Atlas V users guide is 200 km minimum. Delta IV users guide is 185 km. Couldn't find a graph in the Ariane 5 guide, but the minimum to ISS is 200 km. Proton guide is 180 km.QuoteSecond, this altitude isn't used for extended parking, but it can be used as a precursor to a transfer when you want to change the longitude of your Hohmann transfer semimajor axis.I've never seen a launch that goes that low before transfer. Its normally around 200 km.QuoteIt is also useful for planning re-entry; the apogee burn to lower your perigee to 100 km is roughly what you need to ensure proper re-entry angle, so you want 100 km as a reference from any orbit.100 km is too high. You need to target a perigee of around 37 km to ensure re-entry.QuoteComputing dV directly from LEO to LLO would be a solution to the three-body problem, and would depend quite heavily on the route you wanted to take.You don't need to go to the complexity of a three-body system. Just target apogee at Lunar distance and use the hyperbolic transfer formula to perform insertion. Vhyp² = Vesc² + Vinf² where Vinf is your speed relative to the Moon at apogee (assuming the Moon is not there), Vesc is the escape speed from the Moon (Vesc = sqrt(2)*Vcirc, where Vcirc is your required orbital speed around the Moon) and Vhyp is your speed near the Moon before insertion. Subtract Vcirc from Vhyp to calculate your delta-V.QuoteI'm also pretty sure that such an orbit would be more expensive from a dV perspective than going through either EML1 or EML2.I'm pretty sure that is wrong. Going direct using Hohman transfers will always have a lesser delta-V. Here are some numbers using NASA's ground rules and assumptions (information provided by Ross Tierney).TLI: 3175 m/sLOI: 1018 m/sTotal: 4193 m/sEML-1: 3125 m/sEML-1 Insertion: 640 m/sEML-1 to LLO: 1333 m/sTotal: 5098 m/sEML-2: 3225 m/sPerilune: 184 m/sEML-2 Insertion: 147 m/sEML-2 to LLO: 1333 m/sTotal: 4889 m/sQuoteGiving Mars as the highest destination would be a four-body problem, which is even worse than a three-body problem.Four body? Its three-body (Sun, Earth and Spacecraft) as Mars gravity is insignificant near Earth and vice versa. Again, you also don't need to go to that detail. Just pick the greatest Mars radius around the Sun and use the hyperbolic transfer formula. Its so simple, a child can work this out, as shown in this colouring book.http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106

Are you sure about EML1- LLO DV (1333)?. This would make it 3200m/s to surface, I thought it was around 2700m/s.

There are multiple NASA Ground Rules and Assumptions I would like to add delta-V for Near Rectilinear Orbit (NRO) as a chosen destination of DSG in cis-Lunar Space - TLI burn delta V 3,150 m/sec (from circular 200 km LEO parking orbit)- Mid-course corrections delta V 75 m/sec - Perilune burn delta V 178 m/sec - NRO Insertion delta V 250.5 m/sec - Rendezvous and docking delta V 100 m/sec Subtotal inbound leg of the mission delta V 3,753.5 m/sec Source: Options for Staging Orbits in Cis-Lunar Space