PAYLOADS COMPARISONS
The Payloads Comparisons sheet contains 60 CEPE payload results compared to promulgated payload data for various rockets at specific orbital/trajectory conditions and manned or unmanned configurations. The values entered in cells B4 to B9, E4 to E22 and K4 to K22 of the Rocket & Payload Selections sheet are the major components for a specified rocket, which are assumed to be known by potential CEPE users and are, therefore, not shown on the Payloads Comparisons sheet. If it is not the case, refer to the reference documents shown in column (V) of this sheet.
The "Inclination init/final" column (B) shows the values (in degrees) entered in cells T48 and T20 of the Rocket & Payload Selections sheet. The "Perigee" and "Apogee" columns (C and D) show the values (in km) entered in cells Q22 and Q21 of the Rocket & Payload Selections sheet. All 60 Payloads Comparisons sheet cases use a value of 28.5 degrees as launch site latitude in cell N46 of the Rocket & Payload Selections sheet.
The "Type" column (E) indicates if cell T11 of the Rocket & Payload Selections sheet should contain "1" (manned flight) or "0" (unmanned flight). Other than TEML1I, TEML2I, TSEL2I, TLI or TMI flights where fast manned trajectories are possible, this cell has no impact on estimated payloads. The "TxI" column (F) indicates which (if any) of the cell T12, T13, T14, T15 or T16 has to be changed to "1" to indicate a flight away from LEO.
The "Core tank offload %" column (G) indicates the percentage of propellant gone from the main core stage by the time the rocket raised above the launch pad. This is estimated to be 1 % for all rockets with a core stage. Cell E1 of the Rocket & Payload Selections sheet is equal to 100 minus this value. The "Upper stage tank offload %" column (H) indicates the percentage of propellant offload for that stage. Cell K1 of the Rocket & Payload Selections sheet is equal to 100 minus this value.
The "Interstage mass" column (I) shows the mass used in cell H30 of the Rocket & Payload Selections sheet. "generic" indicates that zero is entered in cell H30 and, therefore, CEPE will calculate and use a generic mass for the interstage. The "Fairing mass" column (J) indicates the mass entered for the fairing of unmanned flights. This value is entered in cell H19 of the Rocket & Payload Selections sheet. "generic" indicates that CEPE will calculate the fairing mass using the diameter size entered in cell H16 of the Rocket & Payload Selections Column (K) shows the values of fairing diameter size expected for each rocket. This diameter if bigger than the core tank/upper stage may also impact the rocket drag losses. The "LAS mass" column (L) indicates the mass entered for the LAS on manned flights. This value is entered in cell H4 of the Rocket & Payload Selections sheet. Column (M) shows the expected payload adapter mass for each rocket while colunm (N) shows the expected diameter. "internal" indicate that the adapter is inside a fairing and therefore will not impact the rocket drag losses. Values in parentheses in column (K) and (N) are not used to calculate the mass of the fairing/payload adapter as these masses are found in columns (J) and (M).
The "Payload added in LEO" column (O) shows the mass used in cell Q6 of the Rocket & Payload Selections sheet. The Altitude loss while in LEO (column (P)) is the orbit decay before TxI burn which is entered in cell Q9.
The "Prop load" column (Q) shows the maximum gross propellant payload value derived in cell N7 leaving a surplus delta V in cell U25 of the Rocket & Payload Selections sheet. The "Cargo load" column (R) shows the maximum gross crew/cargo payload value derived in cell N6 leaving a surplus delta V in cell U25 of the Rocket & Payload Selections sheet. The valuess of column (S) show the exact difference (in %) between CEPE estimations and gross payload "official" numbers (shown in column T) published in reference documents found in column (V). Values of column (S) are color coded to indicate how close CEPE estimations are. If published, the "Net payload" column (U) shows reduced payloads which include a reserve growth factor. If only the net payload is available in the reference document, the gross payload of column (T) is calculated assuming a margin factor of 10%.
The following sheet shows how the payload in cell R46 of the Payload Comparisons sheet (for the Ares V (51.0.39) rocket) was obtained:
