RTCC MFD

Introduction

The RTCC MFD is one of the three MFDs within the NASSP releases. Originally created to calculate the Apollo 7 rendezvous maneuvers, the MFD has expanded to include many more features which during the Apollo program were provided by Mission Control (MCC) and the Real-Time Computer Complex (RTCC).

Currently the features of the MFD are:

• Calculating rendezvous maneuvers by solving Lambert's Problem (Useable for the Apollo 7 phasing, NCC1 and TPI maneuvers).
• Coelliptic maneuvers (Usable for the Apollo 7 NSR burn).
• Generic orbit adjustment maneuvers (Usable for the Apollo 7 SPS burns).
• Return to Earth trajectories from anywhere in the Earth-Moon-System.
• All types of IMU transformation matrizes (REFSMMAT) used for the Apollo spacecraft.
• Lunar orbit insertion maneuvers, including Translunar Injection (TLI) and Midcourse Corrections (MCC).
• CSM and LM State Vector Update.
• Uplink to the AGC for Contiguous Block Updates.
• Displaying various Pre-Advisory Data (PAD).

Main Menu

First Page:

• LAM: Lambert Targeting.
• CDH: CDH/NSR maneuver.
• ORB: Orbit Adjustment.
• REF: REFSMMAT.
• ENT: Reentry.
• LOI: Lunar Insertion.
• SV: State Vector
• LMK: Landmark Tracking.
• MAP: Map Update.
• MAN: Maneuver PAD.
• ENP: Entry PAD.

Second Page:

• VEC: VECPOINT.
• CFG: Configuration menu.

Lambert Targeting

The MFD uses advanced algorithms to efficiently solve Lambert's Problem. Lambert's Problem can be explained as finding the velocity vector V1 that leads to an orbit between position vectors R1 and R2 in the time DT.

The Lambert Targeting functionality of this MFD allows multi-revolution calculations and uses a predictor-corrector algorithm to find a solution even in a non-spherical gravity field. This functionality has its limits and will not work beyond a few revolutions. In this MFD instead of a time difference DT the user can set the GET for the maneuver (T1) and the time of arrival (T2). The position vector R2 is always the position of a target vessel or an offset to a target vessel. The displayed maneuver Delta V is the difference between the calculated V1 and the velocity at T1 before a maneuver.

Buttons

• T1: Manuever Time. If the maneuver is supposed to be executed with a specified elevation angle relative to the target, type "E=27.45" to find the T1, when this elevation angle occurs. For this a target already needs to be set.
• T2: Arrival time at the (offset) target. If this time is specified as relative to T1, type "T1+35min" to set T2 to a time 35 minutes after T1.
• N: The number of revolutions from the maneuver (T1) to arrival (T2).
• AXI: Multi-Axis maneuver as the default. An X-Axis maneuver only consists of a prograde or retrograde impulse. This can be used to achieve phasing relative to a target, without the need to also achieve a specific relative height or position offset left or right. Useful to minimize DV for simple phasing maneuvers.
• SPH: Changes the calculation mode between spherical and non-spherical (perturbed) gravity. The Perturbed mode forces a multi-axis manuever.
• TGT: The input for the target vessel. Switches between all vessels in the simulation.
• CLC: Calculate the burn solution.
• OFF: Set the offset from the target. Use e.g. "X=2.05" to set the individual parameters.
• PHA: Choose a phase angle relative to the target vessel. This will calculate the necessary offset distance in front or behind the target.
• UPL: Uplink the maneuver solution to the AGC.
• BCK: Go back to the main menu.