Interesting and informative: the flight to the ISS on the PTK NP

We continue the cycle of posts about Orbiter. What pleased me very much, according to orbithangar.com statistics, after the publication of the second article, I downloaded materials for both it and the first article. And today, gradually increasing the complexity of the tasks, we will go to the ISS on a promising transport ship of the new generation (aka PTS and PTK NP).
This post has the following tasks:

• Tell about the "Angara" and the "Vostochny" cosmodrome.
• To give an idea of ​​the physics of maneuvers for the implementation of docking.
• Provide a simple guide for the implementation of the virtual flight to the ISS and docking with it.

A warning

This cycle of posts about Orbiter comes from the idea of ​​a consistent increase in complexity. Before taking action on this instruction, I recommend you to familiarize yourself with the previous posts: the history of cosmonautics , "Breeze-M" .

Introduction

We will talk about the PTK NP ship itself in the next post, in which we will learn to return from the ISS. And here we will talk about the Angara rocket and the Vostochny cosmodrome, because it is from the Vostochny and on the Angara we will start.

A bit of history and theory

The docking is a rather complicated maneuver, the first docking took place five years after the first manned flight into space and nine years after the beginning of the space era: the Americans did the first docking in manual mode on March 16, 1966 (Gemini-8 is the target of Agen) , the first fully automatic docking was conducted by the USSR on October 30, 1967 (two unmanned "Soyuz").
Why is it so hard? From the point of view of ballistics, a brief description of the docking process seems simple: you have to get to a point close to the target, reset the mutual speed, then come up and dock. However, the implementation of this - a difficult thing. The earth rotates, so you need to start in a very short interval (often less than a second). The launch vehicle must bring the ship very precisely into orbit with the given parameters. Coupled ships must have a delta-V stock for maneuvers and docking, and there must be a well-developed mathematical calculating apparatus and equipment for measuring motion parameters.
It was the docking that made flights to the moon without direct-landing monstrous ships accessible — a fairly light lunar module separated from the command in the moon's orbit, sat down, took off and docked again.
Of the interesting two stories worth noting:
In 1962, the USSR, using highly qualified ballistics and high accuracy of the launch vehicle, launched Vostok-3 and Vostok-4 into very close orbits. The closest approach between the ships was only 6.5 km. There were no orbital maneuvering engines on the "Vostokov", they could not dock, but such accuracy of the launch made a splash at that time.
In 1966, during the flight of the “Gemini-12” radar refused, which was used to measure distance and relative speed. But the crew was Buzz Aldrin, who was extremely interested in orbital maneuvering issues and shortly before that defended his thesis on the subject of manual rendezvous. Using only a sextant, Aldrin successfully docked.
')

RN "Angara"

The "Angara" rather complicated story. The first project was created in the early 90s, when Baikonur was in an independent state, and the prospects for rocket launches from it were unclear. The cooperation of the factories was also disrupted. In the absence of money, a very unusual scheme was chosen that would allow the use of an almost ready start at Plesetsk:

However, after a while, the severity of the problems somewhat smoothed out. With Kazakhstan, it was possible to more or less agree, rockets, even toxic Protons, could be launched. But there was no money to create a new rocket. Therefore, the design in the area of ​​1997 actually began anew. On the one hand, the lack of haste made it possible to think about how to make a good rocket. On the other hand, the lack of money meant that for many years the rocket would not leave the level of drawings, pictures and models. The concept of the rocket shifted towards the so-called. universal rocket modules (URM), from which you can make a light, medium, or heavy rocket.
Until the mid-2000s, there was no money for a full-fledged development, and the work was carried out on the initiative of the developer (Khrunichev State Research and Production Space Center), of course, very slowly and again without going beyond sketches and layouts. Cases in the economy gradually improved, the state became stronger, solved primary problems, money began to appear on the space program. Full rocket work began somewhere in the second half of the 2000s.
The development was also helped by a contract with South Korea, for which the first stage of the KSLV-1 rocket was made, which is actually the URM of the future Angara. The tests with the Koreans were successful, in all three starts the first stage worked normally. In the first launch in 2009, an accident occurred due to the incomplete separation of the fairing of the head part of the Korean production. In the second launch, the Korean missile detonation system triggered in an accident that blew up a “healthy” rocket. The third launch in December 2012 was completely successful. I watched that launch live, I remember, I was very scared - the rocket was very actively maneuvering, moving away from the start, it seemed that it had lost its stabilization.

Currently, work is actively underway - workshops have been built, a start has been built at Plesetsk, and tests are underway. The first launch of the light "Angara" will almost certainly be this year. If everything goes smoothly, then perhaps a heavy rocket will fly for the first time this year. On the state of affairs you can watch the transfer of TV Roskosmos and the channel "Star":


And the latest news with photos from the site "Made with us."

The need for "Angara"

A new rocket is needed for the following reasons:

1. It is strategically necessary to be able to launch payloads from its territory.
2. "Proton" uses toxic components of the fuel, which is inconvenient and expensive, incl. Kazakhstan has to pay for the decontamination of the fall fields.
3. The new rocket can realize new technologies at a level that is unavailable for upgrading old rockets, and will allow launching cargo into space cheaper, more reliable and, in general, more efficient. For example, for a new rocket it is easier to make a hydrogen upper stage than to try to put such a stage on the “Proton”.
4. The new rocket may become more powerful than the Proton (variants A7), which will make qualitatively new types of payloads available.

Cosmodrome "Vostochny"

The history of the Vostochny cosmodrome is somewhat similar to the history of the Angara rocket. In exactly the same way, in the early nineties, the need arises for its own cosmodrome, on the basis of the positional region of the ICBM, the “Free” cosmodrome is created, which produces five launches from 1996 to 2006, and in 2007 it practically ceases to exist. But already in 2009, the Vostochny launch site began to be built in the same area. The positive experience of implementing large projects (a bridge to Russky Island, the Olympiad) suggests that the spaceport will be successfully built, especially since this is now a priority for the development of the country:

The need for "Eastern"

1. The strategic need to have a space center on its territory. "Plesetsk" because of its very northern location is suitable mainly for launches into the polar orbit.
2. Fields of fall will be located on, firstly, their own, and secondly, unpopulated territory, which should increase the effectiveness of launch vehicles limited by existing fall fields.
3. A secondary goal is the development of the economy of the Far East.

Flight preparation

In order to go on this flight, we need:

• Orbiter itself , if you still have not downloaded it.
• Addon PH "Angara" .
• Addons Spacecraft3 and Multistage2 from here .
• Addon "PTK NP" .
• New DLL for Orbiter 2010.

Flight plan

Flight to the ISS can be divided into the following stages:

1. Launch and launch.
2. The combination of the planes of the orbits.
3. Lifting the apocenter to the intersection with the ISS orbit.
4. Orbit synchronization
5. Rapprochement and docking.

Stage 1. Launch and launch

This stage lasts from the preparation for launch to the entry into the reference orbit.
PTK NP scenario - 1. Launch to ISS

Welcome to the Vostochny Cosmodrome! The Angara-3P with three URMs is used in the scenario for launching the PTK NP on the ISS, but this is most likely already outdated information, the PTK has become heavier and already requires Angara-5P with five URMs. After loading the script, you must press the P button to start at 20:00:00 (20 seconds of simulation). If you press the button sooner or later, it will increase the difference in the inclination of the orbits due to the rotation of the Earth.

Further removal occurs automatically. I do not recommend increasing the speed of the simulator, because the derivation algorithm does not have feedback, and its accuracy decreases with increasing simulator speed.
Pay attention to how the central power unit changes. This is also an assumption of the simulator, in reality it is planned to overflow the fuel from the side blocks into the central one by means of overpressure.
After the launch, we are in orbit about 250x400 km with an inclination of 51.6 degrees. After separation, you can press G to expand the antennas and solar panels, for beauty, it will not affect the flight.

Stage 2. Combining Orbits

If you started on time, the angle between the orbits will be close to 0, but in this tutorial I deliberately made a small mistake for clarity of the maneuver on combining the orbits. Switch the left MFD to the orbit alignment mode: Left Shift + F1, Left Shilt + A. Select the ISS as the target: Left Shift + T , in the spacecraft window that appears -> ISS . In our case, the angle between the orbits is half a degree:

From the scheme, the algorithm of actions becomes clear:

• Maneuvering over the alignment of the orbit planes should be carried out in the area of ​​the node line.
• In the ascending node, it is necessary to give an impulse "down" ( Nml- ) from the plane of the orbit.
• In the descending node, it is necessary to give an impulse "upwards" ( Nml + ) from the orbit plane.
• If in the process of maneuver the line of nodes has moved down strongly to the side, the maneuver must be continued when we again find ourselves at the line of nodes.
• You can use auto-positioning - Nml + - key, Nml- - e .
• There is a clue in MFD what you should do, but if you know the physics of the process, it is more likely to interfere, and it can also be wrong.

Also, the PTK NP differs from the Briza-M in a more developed motor system. First, there is no need to besiege the fuel - the engine starts to work instantly by pressing a key. Secondly, in addition to the acceleration mode of the main engine ( Num + ) there is a mode of braking by shunting engines ( Num - ). And, thirdly, besides the rotation with standard keys, there is a mode of displacement along the axes (translational controls), it will be described below.
Maneuver start:

There are seven hundredths of a degree left, the maneuver must be repeated in the next node.

The final of the second maneuver, the plane of the orbits practically coincide.

Stage 3. Raising the apocenter to the intersection with the ISS orbit

For this we need a new MFD - Transfer MFD. Turn it on in the left panel ( Left Shift - F1 , Left Shift - X ). Select the target of the ISS - Left Shift + T , in the Spacecraft window that appears -> ISS . It should turn out something like:

Turn on the HTO mode (HTO button on the MFD). A dotted radius appears, indicating the starting point of the maneuver. Move it with the Left Shift - < and Left Shift -> keys to the area of ​​the pericenter (indicated by the shaded dot on the right MFD). Since we are in orbit "inside" the orbit of the ISS, we need to accelerate. Change the hypothetical delta-V with the keys Left Shift - '' - '' and Left Shift - '' + '' to the intersection with the ISS orbit (two new radii will appear). These radii indicate the position of the intersection point (gray) and the target when the ship is at the intersection point.

We are behind the ISS, however, since our orbit is lower, we are catching up with it. Therefore, you need to wait until the calculated position of the ISS is in the vicinity of the intersection point of the orbits, something like this:

We are waiting for the maneuver point and give impetus. Delta-V is positive, so you need to accelerate. Do not forget that it takes time to navigate to maneuver, take a position on the vector of orbital speed in advance - 200-300 seconds before the maneuver point, press [ for automatic orientation of the ship. Note that the Dv line on the MFD shows the approximate maneuver time in seconds, and the line above, DTe, shows the time remaining to the maneuver point. Simply put, start overclocking when DTe is equal to Dv or half of it. If you did everything correctly, the result of the maneuver will be approximately the following:

Stage 4. Orbit synchronization

The task of this phase will be to be in one point of space at the same time as the ISS. To do this, we will perform rough synchronization using Transfer MFD and fine synchronization using Sync Orbit MFD.
Since, according to the testimony of the MFD, we will be ahead of the ISS at the next turn, we need to raise the pericenter in order to increase the period of our orbit. We will plan a maneuver in Transfer MFD - move the maneuver marker to the orbit intersection area and set delta-V such that the ISS markers and intersections are as close as possible to each other. Also, in advance, we will transfer the right MFD to Sync Orbit mode - right Shift - F1 , right Shift - Y. It will look like this:

Upon reaching the point of the planned maneuver, we raise the pericenter of the main engine. It should make something like

Now we are switching to the mode of movement by shunting engines. To do this, either click with the mouse on the LIN button on the left-top, or press Num / . The difference between the modes clearly:

In this mode, we begin to maneuver, focusing on the value of the string DTmin on the right MFD. Our goal is to make it as close to zero as possible. The correct result is as follows:

Stage 5. Convergence and docking

Prepare for docking. Switch the left MFD to the docking mode - Left Shift - F1 , Left Shift - D. Select the first MKS docking station - Left Shift - T , in the appeared window - ISS -> dock 1 . We will display connection parameters on the HUD - click the HUD button on the MFD. It should turn out something like:

ISS is accidentally right in front of us, at a distance of 700 km. Less than through the turn, it will catch up with us "from behind", and we will have to maneuver so that it does not crash into us. A few hundred seconds before the meeting, we need to navigate to the deceleration (relative to the ISS, in terms of orbital mechanics, this is acceleration) - by switching to the rotation mode, we find the token -V [ISS] . In this case, we will maneuver the most efficiently - the most powerful, sustainer engines.

PTK NP has powerful engines, it is possible to brake at a distance of 3-5 km from the ISS. The distance to the ISS and the direction to it are indicated by the D [ISS] marker, the relative speed by the V [ISS] and -V [ISS] markers. Having extinguished the speed, we turn around with our nose on the ISS and begin a rapprochement. our task is to place a marker of our movement on the ISS and hold it there while working with the shunting engines in shear mode. Maneuver carefully, do not allow large values ​​of speed, then it will have to be extinguished. Illustration of the convergence process:

Pay attention to the line of markers that are designed to facilitate the process of convergence. At a distance of less than one kilometer, move the direction marker to the “corridor” of the docking:

Our task is to slow down inside this corridor and take the correct position for docking. It will look like this:

Let us consider the MFD docking in more detail:
The triangle on the outer circle is the position of the apparatus. When it is on top, it glows white and means that our top coincides with the top of the ISS docking station.
Oblique cross is an indicator of orientation, i.e. how far we are rotated relative to the correct position of the dock.
The straight cross is the docking axis, i.e. how far we are offset from the correct axis of the dock.
If you do everything correctly, the oblique and straight crosses will be on the MFD axis, and the triangle will be white and on top, as shown in the figure above. Having orientated the ship, we begin to converge, keeping the motion marker on the ISS and tracking the indicators of the MFD.

Get closer. Finally came out of the shadows.

Left just a little bit.

There is a dock!

Epilogue

I recommend saving the state of the simulator - exit Ctrl-Q and press the Save Current button. In the window that appears, specify the name and description of the file.
If the docking seemed to be simple, you can enable orbit distortion ( Parameters -> Perturbations ), as well as train in fuel economy.
Russian-language manual for in-depth study.