Что новенького про американцев на Луне

294:59:25 Worden (onboard): .05G light.

[On the EMS display, the 0.05g light comes on at 294:59:25 - within a second or two of when Mission Control predicted.]

[During entry, the crew's attention is focused primarily on three displays: The FDAI (Flight Director Attitude Indicator, or more commonly known as the "8-ball"), the DSKY, where entry data such as range-to-go, deceleration and velocity are displayed, and the Entry Monitor System (EMS).


Diagram of the Entry Monitor System (EMS) panel.

The EMS is not a single display, rather, it is a specialized guidance and display system to present critical entry parameters to the crew. Surprisingly, the EMS does not generate guidance or trajectory information for the spacecraft computer, nor can it actively control the spacecraft during entry. Its function is only to display the most relevant data to the crew as they plunge through the atmosphere. Three displays on the EMS provide the situational data necessary to evaluate the progress of the entry: A scrolling display showing velocity vs. deceleration, the RSI (Roll Stability Indicator), and a digital velocity indicator.]

[Most attention is focused on the velocity vs. deceleration display, a 9-cm window behind which is a scrolling Mylar tape marked with the acceptable velocity and G-force boundaries. The tape moves from right to left, and an illuminated index, or "bug", traces the current velocity-acceleration profile onto it. Of course, keeping the Command Module within the narrow entry corridor requires maneuverability within the atmosphere. A modest amount of lift is generated by the Command Module which can be vectored in any direction by rolling the spacecraft. The RSI shows the desired lift vector (up or down) by two lights, and a pointer that displays the current lift vector, which is used to confirm it is within the entry corridor. Finally, a digital velocity meter provides an additional source of velocity data to the crew.]

[Prior to entry, the CM is in a heads-down/lift vector up attitude with the heat shield forward. Program 63 (Entry Initialization) begins executing on the computer. P63 determines and displays entry parameters such as range-to-splashdown, maximum expected G-force, and bank angle. It holds the CM in the correct attitude and senses the point that a deceleration of 0.05g has been reached. Once the program is running, there is little to do but wait for the 0.05g light on the EMS to illuminate, indicating that the first tenuous layers of the atmosphere are exerting their decelerating force on the spacecraft. At this point, P63 automatically runs Program 64 (Post 0.05g) This is an important milestone, reached about 29 seconds after the Command Module passes the Entry Interface, and marks where The EMS scroll begins to run. There is no fixed altitude at which this occurs as it depends completely on spacecraft shape, velocity, and the local atmospheric conditions. Once this boundary is reached, the hard work of entry begins.]

[Program 63, which had been monitoring the entry up to this point, terminates and Program 64 (Entry - Post 0.05G) is started. The DSKY displays the bank (roll) angle commanded by the guidance computer, velocity and acceleration. It is no coincidence that these values are duplicated on the EMS; both systems operate independently, and if one fails, the other can be used to complete the return to Earth. The scroll on the EMS window begins to move to the left in proportion to velocity, registering velocity on a scale at the bottom of the mylar tape. The scroll "bug" moves downward as g forces build up on the spacecraft, and leaves a tracing on an emulsion on the back of the tape, giving essential information on the progress of the entry. The boundary lines pre-printed on the scroll tape describe the limits of velocity and G-load (deceleration) that ensure the CM is within the entry corridor. If the spacecraft is descending too steeply with respect to the corridor, its progress will become apparent on the scroll. At the same time, the roll stability indicator will flash a light (the corridor control light) indicating that upwards lift is necessary to shallow out the entry trajectory.]

[In the movie Apollo 13, the character that portrays Jack Swigert (played by Kevin Bacon) is shown in the simulator performing an entry exercise. The simulator supervisor introduces an anomaly, a "corridor light", which he misinterprets and flunks the simulation. Diagram describing the limits of velocity and G-load.



The error the character made was not to cross-check the "malfunctioning" Roll Stability Indicator against the DSKY display and the entry scroll display. Of course, in reality Jack Swigert handled the procedure expertly.]

 

Xan> Да ещё, возможно, чисто механический!

Возвратная ракета представляет собой самостоятельный ракетный блок с однокамерным жидкостным реактивным двигателем тягой 1850 кг и системой из трех сферических баков с компонентами топлива тетроксид азота и несимметричный диметилгидразин. Диаметр центрального бака 67 см, диаметр каждого из периферийных баков 53 см. Система подачи топлива — вытеснительная. Для стабилизации ВР на активном участке служили рулевые сопла общей тягой 70 кг. На центральном баке укреплен цилиндрический приборный отсек диаметром 56 см, внутри которого установлены электронные счетно–решающие и гироскопические приборы системы управления ракетой, приборы бортового радиокомплекса метрового диапазона (101,965 МГц по линии Земля — борт и 183,537 МГц по линии борт — Земля) с телеметрической системой, аккумуляторные батареи и приборы бортовой автоматики.

В состав системы управления, обеспечивавшей построение и запоминание системы координат в момент старта, стабилизацию аппарата при работе двигательной установки, входили курсовой гироприбор, состоящий из двух свободных гироскопов, гироскопический интегратор продольных ускорений, автомат стабилизации и автомат отключения двигателя. В качестве исполнительных органов системы стабилизации на активном участке использовались рулевые сопла двигательной установки. Учитывая малое время полета возвратной ракеты, в системе энергопитания были использованы одноразовые серебряно–цинковые батареи емкостью 14 Ампер–часов. На внешней поверхности приборного отсека ВР установлены четыре штыревые приемно–передающие антенны.