Product Descriptions and Delivery Schedules

The United Space Alliance (USA) Flight Design Department delivers a set of data products for each flight design cycle. The ARD Support staff is on electronic distribution to receive mail through the FADS system to PC mail, notifying them when many of these products have been electronically delivered to the master storage area on FADS. Along with notification, specific products documented in the Ascent FDO Electronic Datapack in Appendix D.15 are also mailed to designated ARD Supports. The...

Procedure

MONITOR FLTR STATUS COMING UP ON MECO o WHEN VI STABILIZES RECORD MECO VI AND UNDER OVERSPEED FROM THE FDO LAUNCH DIGITALS REPORT THE UNDERSPEED OR OVERSPEED TO FDO BACKGROUND Once MECO has occurred, FDO requires a MECO condition assessment. ARD Support, along with the rest of the backroom support team, provides inputs on the MECO condition in the form of underspeed (or overspeed). The MECO status is easily obtained by looking at the O S or U S value on the FDO LAUNCH DIGITALS in the...

Background

When an engine-out occurs, the FDO pushes the appropriate engine-out PBI twice. This gives the ARD an initial estimate of the engine-out time and Earth-relative velocity. TRAJ later gives DYNAMICS a more accurate time and velocity of main engine out (TME-OUT, VME-OUT) from the onboard telemetry. The PRI and BFS engine-out time and velocity are downlisted and displayed on the ARD OUTPUT display in the lower left portion of the display. The engine status word is downlisted via telemetry once...

Media

Product Identification Flight Cycle Product Name MDS path - Gets files and default values from OPIS, Other paths -Lists files in directory. Edit as needed. (Each field must have a string, either an input value or '-', and be separated by spaces.) Printer Print Print Print Font Type Font Paper _Seq Command Header_Size Orient I Sets new defaUt values and overrides valuesfrom OPIS Prints dist. list(s) for files listed above (Writes files listed above which have paper as their media Allow...

Ardin

This module has an input task that performs a processor input parameter initialization of all input variables that reside in either the Ascent Constraints Table (ACT) or in the systems parameters. This is done only once per launch during the first ARD cycle. ARDIN also interfaces the ARD with the SS, the system parameters, and the ACT. This interface inhibits any changes in ARD input parameter values during subsequent ARD execution of this cycle. The SS state vector and time are extrapolated...

Further Work

Booster Officers are currently evaluating how much LOX imbalance is sufficient to guarantee NPSP requirements in the event of a stuck throttle and low performance. If the ARD can be used to assist in the realtime evaluation of this, then it may be possible to avoid shutting down a stuck engine low performance at 23k for low MR cases. This would eliminate most of the imbalance error for the stuck throttle case and make correction of the ARD output unnecessary. (This would not alter procedures...

Nominal PostMECO

The post-MECO equivalent of the ARD is the AME. The ARD transfers mass properties (orbiter, OMS, and RCS weights) to the AME. Therefore, it is important to have the correct ARD masses prior to MECO. The AME uses selected source state vectors, mass properties, and OMS engine configuration to determine highest available mission mode. The AME evaluates multiple sets of OMS-1 and OMS-2 targets that are delivered by the post-MECO flight design group. The AME is initially configured to automatically...

Figure ARD imbalance error correction chart

For biased as well as stuck-throttle cases, these errors are primarily experienced during the last minute of powered flight. Therefore, if a low MR bias-throttle case occurs prior to 3-g throttling, then the error will be present. For lockups, if the engine is to be shut down manually (and it is a low MR case) then these errors will be present. The value from the chart represents a positive bias applied to the ARD AV margin output. Realtime procedures worked out with DM46 E. P. Gonzalez, M. R....

OMS He Leak Purpose

To accurately model OMS helium leak cases (OMS He TK P Low) in the ARD. PROCEDURE IF PRE-MECO DUMP REQUIRED AND TANK FAIL EXPECTED PRE-MECO o Use OMS Prop Leak Fail & Helium Tank Fail procedure (see Section 4.2.7.1) IF PRE-MECO DUMP REQUIRED AND TANK FAIL NOT EXPECTED PRE-MECO o V FAILED OMS ENGINES 1 (AFTER 2E TAL) o V TRAJ ENTERS ITEM 9 PER PROP OFFICER (SLIP OMS ASSIST START TIME, IF NECESSARY) o Using He LEAK table LB TRAPPED for leaking side expected total dump duration, PASS TRAJ DOMS...

Ard Mass Track

Besides utilizing the input state vector, the ARD must track the current vehicle mass and propulsive masses during powered flight. This is done by maintaining a nominal throttle history table, the initial propulsive and non-propulsive masses, and the dry component masses for the entire stacked vehicle. The ET propellant history table is a large array that contains timetags and corresponding MPS fuel quantities. It is built in realtime by the ARD, starting from the knowledge of how much usable...

SSME Thrust and ISP

The thrust and ISP errors are 6 1 dispersions that uniquely affect realtime FPR computation and, thus, the ARD. The major detrimental effect of both the ISP and thrust uncertainties is a mass flowrate (mdot) error. The flowrate error builds a mass error over time - the later into the ascent profile, the greater the uncertainty in the usable MPS. A pound of propellant near MECO is worth a lot more (AV-wise) than a pound of propellant earlier in second stage. The relationship between the two is...

Nasa

National Aeronautics and Space Administration Lyndon B. Johnson Space Center Houston, Texas ABORT REGION DETERMINATOR SUPPORT CONSOLE HANDBOOK Original Signed by Sarah R. Graybeal William E. Powers, Lead Ascent Entry Flight Dynamics Group P. Jeff Bertsch, Chief Ascent Descent Dynamics Branch NATIONAL AERONAUTICS AND SPACE ADMINISTRATION LYNDON B. JOHNSON SPACE CENTER HOUSTON, TEXAS 97-1 11-14-97 Replace front cover. Add PCN History page ii. Replace table of appendices page xii. Add Change...

Background Information

The ARD is a launch abort processor resident in the Mission Control Center MCC . The ARD provides realtime cyclic ascent performance prediction capability. The ARD calculates abort capability for all of the intact abort modes Abort To Orbit ATO , Abort Once Around AOA , Transoceanic Abort Landing TAL , and Return To Launch Site RTLS . The ARD also has the ability to calculate abort capability for certain contingency abort modes and the capability to achieve the nominal Main Engine Cut-Off MECO...

ARD Concept and Usage

Starting with the current State Vector SV , the ARD calculates velocity changes DV required to achieve various trajectories nominal, ATO, AOA, TAL, and RTLS . This is compared to current DV available based on calculated External Tank ET propellant remaining and SSME status. This excess capability is expressed in terms of SSME propellant equivalent velocity margin and is displayed digitally on the ARD OUTPUT display and graphically on the DV MARGIN display. These functions are performed for the...

Procedures to Configure TSA Entry Processors

ARD Support is responsible for configuration of TSA entry processors, as defined in the Trajectory Subsystem Upgrade Project, TSUP-Era Data Recon Ops Concept document authored by C. Edelen. This configuration is done via the Standard Init Pad, as described in Section 2.2.3.1 and shown in Figure 2-6. The ARD Support is responsible for configuration of the Generic TSA Engine Characteristics Table ECT , DMP Deorbit Constraints Table DCT , Solar Flux Table FLUX , Selection Files, and TSA VAT files....

Post Engineout Thrust Update Accuracy

The thrust update algorithm was not designed to compute thrust deltas after an engine failure, due to the enormous task of correlating margin drift to thrust error for different abort modes and engine failure times. Data continues to be output after an engine failure however, once an abort is selected, the algorithm is terminated. Note that a thrust restore can still be performed when the thrust update algorithm is no longer active. After a PBI thrust update has been performed, the ARD 100...

Ssme Thrust And Isp Dispersions What They Are How They Are Handled And How They Affect The Ard

The mystical world of Dispersions and FPR can be very confusing. I find that a lot of it is due to not understanding the terms used, and the improper usage of those terms. Poorly labeled charts, lack of derivations, and few references also cloud the picture. This document will attempt to clear up some of the confusion. One of the first things that I found confusing was the use of the word dispersion. There are two flavors of dispersions. First, there is a dispersion, mechanical or...

Communication Loops

Communication loops are usually recorded therefore, do not say anything you do not want replayed. The recordings facilitate post-flight reconstruction of events that occur during the mission. Note also that Flight Directors call sign FLIGHT sometimes monitor backroom loops, even during simulations. While communicating on the loops, certain etiquette should be observed. Common sense works well in this area. A few simple rules include When initiating a conversation, call the party's position...

DOL ILoad Update Dolilu Ii Procedures

DOLILU II implements DOL uplink of the throttle profile and first-stage steering parameters along with associated wind and atmosphere data. The command loads containing this information are built from a corresponding TRS data table, which is updated on launch day based on offline DOLILU II processing. The required values are transferred from the FADS system to the TRS, from which DYNAMICS builds a Group MED by which the TRS data tables may be updated. Accuracy of ARD processing is affected by...

Figure Trajectory Matrix

The source of each piece of information is as follows Nominal Throttle Maximum SSME throttle setting during nominal powered flight. Found in the Level A Groundrules and Constraints G amp C , delivered throttle tables, asct08.iloads THROTT 4 , etc. Usually 104 or 104.5 percent. Abort Throttle Maximum SSME throttle setting during intact aborts. G amp C, asct08.iloads KMAX . Usually 104 or 104.5 percent. Max Throttle Maximum SSME throttle setting for contingency aborts. G amp C, asct08.iloads...

Reformatting an ASEV

1 Use Microsoft Word to open the document. 2 Go to File gt Page Setup to change all the margins to 0.5, except left to 0.7. Be sure to check that the Apply To box is set to Whole Document. 3 Next, go to Tools gt Templates amp Add-ins. Click on the Attach button and choose ASEV_Summary.dot. It is located in the directory below. Be sure to check the box that says Automatically update document styles. Click OK. 4 Now, highlight each line section in the document and apply the appropriate Style in...

Voice Communications Dvis Logon

Voice communication on console is accomplished with the Digital Voice Intercommunications Subsystem DVIS . To log onto the system, touch the screen to activate it, then push SIGN ON and enter the four-digit keyset ID on the front of the unit. Then press ENTER to complete the logon. Page up or down to select the desired communication loops configuration by pressing the PAGE area followed by the up and down arrows another page will have the 2 loops if you need them. You can then select...

Figure Throttle bucket adjustments for hot and cold SRB

The ARD has a built-in nominal bucket that does not change. The ARD uses TDEL to compute a delta weight DELWT that is applied to the ARD mass track to account for an off-nominal bucket. This delta weight represents the propellant use difference between the planned throttle bucket which is given in the ARD throttle table and the actual bucket. For example, if the real throttle bucket uses less than the planned e.g., hot SRB example above , a positive delta weight is applied to the ARD mass...

Typical Flight Cycle

Figure 2-6 shows a typical flight cycle init pad. Each line in the example is numbered for reference actual init pads are not. Each item and its source are described in Table 2-3 and in Section 2.2.4. See an experienced ARD Support for additional assistance. Note that either the ME can generate group MEDs per the init pad instructions, or the ARD Support can generate the group MEDs using the Auto Group MED AGM Application. However, the MEs have requested that ARD Support generate the CRP, THR,...

Ascent Events Summary

The Ascent Event Summary ASEV is a listing of all major events and abort mode boundaries for a nominal ascent trajectory. Each event is referenced by a MET and inertial velocity Vi . This data is compiled from information contained mainly in the ASCENT MODE BOUNDARY VELOCITIES ASAB 23 , NOMINAL ASCENT DATA ASCT 17A , NOMINAL DELTA-Vs AND STATE VECTOR ASCT 06 flight design data products, and Level A G amp C. Other data sources have to be referenced for some of the inputs to this summary. Refer...