Flight Question How to aim for a landing on Earth in daylight

Marijn

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When I launch the default 'Landed at Brighton Beach' scenario of the XR5 vessel and take-off for a flight to Earth using a direct entry, I arrive in the middle of the night at Cape Canaveral. Also, it's always a bit of a surprise whether I end up approaching from the north or south. I am using the Base Approach program of IMFD to calculate the burns.

I like to be able to have more control about the local time at arrival. And I want to aim for an approach from the north so I can land on runway 15 without having to make any steep turns. When doing direct entries, I somehow need to get the timing right at a very early stage of the flight as there won't be a parking orbit to wait in.

But I don't know how to do this. Simply launching 12 hours later didn't do it.

Anybody who can shed some light on how to achieve this?
 

francisdrake

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That is an interesting point. Usually I play around with the scenario date, to allow for good lighting conditions in the target area. For example
Date MJD 52006.7485132526

If you add 0.5 (half a day) to the date, you have a good chance to arrive in daylight, if previously there was night. The Moon did not move much in half a day, so the travel time should be about the same.

If 12 hours offset did not help, maybe try 6 or 18 hours.
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If the IMFD planning ends up in random approaches from north or south, you could consider flying a Shuttle-type Heading Alignment Cylinder (HAC). This maneuver can be entered from any direction and ends downwind aligned with the runway.

Or <hack>: Set up a base in St. Augustin, Florida, and aim for it during reentry. Passing over it at sufficient height gives a straight-in approach to runway 15 at the Cape. :)
 
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Urwumpe

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The trick is to time your departure from the moon correctly - the time at your landing site depends on the lunar phase. If you depart close to new moon, your Earth orbit periapsis and thus, your reentry, will be close to midnight local time.

Alternatively: Perform a skip reentry
 

IDNeon

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The trick is to time your departure from the moon correctly - the time at your landing site depends on the lunar phase. If you depart close to new moon, your Earth orbit periapsis and thus, your reentry, will be close to midnight local time.

Alternatively: Perform a skip reentry
Wow this sounds amazing. Can you tell me the correlation to why lunar phase and reentry with earth?
 

Urwumpe

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Wow this sounds amazing. Can you tell me the correlation to why lunar phase and reentry with earth?

Lunar phase is nothing else but the relation between the position of the moon and the position of Earth relative to the sun. If you plan to return from the moon to land on the lighted side of Earth, the moon has to be on the opposite side of Earth, as seen from the sun during departure. Which means, it has to be closer to full moon than to new moon. On new moon, a direct return from the moon would always result in you landing on the night side of Earth.

Just try it, Orbiter is great for that. Sadly we have no lunar phase tool to make it easier to find the right time.
 
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