Q on Apollo 7 rendezvous burns: Doin' the math

I've been playing around with the "Orbiter" simulator, specifically
the NASSP add-on, which runs an emulation of the orginal AGC software
(Colussus 249).

On Apollo 7, after separation from the SIVB, the CSM did a couple of
phasing maneuvers, then a "Corrective Combination" burn to put the CSM
in a specific place relative to the SIVB, where they could begin the
rendezvous sequence.

The phasing maneuvers have been calculated, and the rendezvous
sequence looks like it can be done with several programs in the AGC.
The problem is the Corrective Combination burn. I can calculate where
the CSM needs to be when the rendezvous sequence starts, but I don't
know the math involved in calculating the burn to get me to that
place.

Is there any resource on-line that shows the equations that are used
to make that calculation?

thanks,
Scott

Scott Stevenson wrote:
I've been playing around with the "Orbiter" simulator, specifically
the NASSP add-on, which runs an emulation of the orginal AGC software
(Colussus 249).

On Apollo 7, after separation from the SIVB, the CSM did a couple of
phasing maneuvers, then a "Corrective Combination" burn to put the CSM
in a specific place relative to the SIVB, where they could begin the
rendezvous sequence.

The phasing maneuvers have been calculated, and the rendezvous
sequence looks like it can be done with several programs in the AGC.
The problem is the Corrective Combination burn. I can calculate where
the CSM needs to be when the rendezvous sequence starts, but I don't
know the math involved in calculating the burn to get me to that
place.

Is there any resource on-line that shows the equations that are used
to make that calculation?

Not publicly, I'm afraid. The Apollo 7 NCC and NSR burns were targeted
on the ground and the solutions uplinked to the crew to be performed in
P-30 (External Delta-V Program). The algorithms used by the ground
targeting were quite involved and the reports on them are hard to find
even within JSC.

That said, I think it should be possible to fake the NCC burns using the
Colossus CSI targeting program (P-32) and the NSR burn using the
Colossus CDH targeting program (P-33). This is not dissimilar to the way
the CSM would perform the Rescue-2 sequence. However, the first NCC may
require an offline algorithm since the coelliptic delta-H has not yet
been established (the Rescue-2 burn itself was ground-targeted for that
very reason). Let me chew on that for a while and see what I can come up
with.

On Mon, 08 Feb 2010 19:08:54 -0600, "Jorge R. Frank"
wrote:

Scott Stevenson wrote:
I've been playing around with the "Orbiter" simulator, specifically
the NASSP add-on, which runs an emulation of the orginal AGC software
(Colussus 249).

On Apollo 7, after separation from the SIVB, the CSM did a couple of
phasing maneuvers, then a "Corrective Combination" burn to put the CSM
in a specific place relative to the SIVB, where they could begin the
rendezvous sequence.

The phasing maneuvers have been calculated, and the rendezvous
sequence looks like it can be done with several programs in the AGC.
The problem is the Corrective Combination burn. I can calculate where
the CSM needs to be when the rendezvous sequence starts, but I don't
know the math involved in calculating the burn to get me to that
place.

Is there any resource on-line that shows the equations that are used
to make that calculation?

Not publicly, I'm afraid. The Apollo 7 NCC and NSR burns were targeted
on the ground and the solutions uplinked to the crew to be performed in
P-30 (External Delta-V Program). The algorithms used by the ground
targeting were quite involved and the reports on them are hard to find
even within JSC.

That said, I think it should be possible to fake the NCC burns using the
Colossus CSI targeting program (P-32) and the NSR burn using the
Colossus CDH targeting program (P-33). This is not dissimilar to the way
the CSM would perform the Rescue-2 sequence. However, the first NCC may
require an offline algorithm since the coelliptic delta-H has not yet
been established (the Rescue-2 burn itself was ground-targeted for that
very reason). Let me chew on that for a while and see what I can come up
with.

Thanks, Jorge! I really appreciate it!

take care,
Scott