Муртазин Р.Ф.Candidate of Eengieering Science, Rafail Farvazovich MURTAZIN, Trajectory Department, RSC Energia. 

“Quick” rendezvous profile for Russian transportation spacecraft docking with ISS. Project prospects and further development. 

 

The interview is conducted by Oleg Volkov, deputy head of the Great Start project. 

Volkov O.N.: Visiting the web site Korolev’s Planet is the deputy head of trajectory department at RSC Energia, Candidate of Engineering Science Rafail Farvazovich Murtazin, a developer of the “quick” rendezvous profile for Russian transportation spacecraft docking with the ISSR.F. Murtazin is one of the leading specialists of RSC Energia, who became the initiators of the quick profile for rendezvous with ISS and are actively involved in its development and implementation – Ed.].  

Mr. Murtazin, good day!

R.F. Murtazin: Good day!

 

V.: On the August 1 of the last year all the space buffs were somewhat taken aback when they learned that Progress M-16M docked with the ISS not two days after the launch, but just five hours after the lift-off. On October 31 they did this trick again. Could you please tell us where this idea of “quick” docking came from, and why is it that it only became possible now? 

M.: A good question, and I especially liked the word “trick”! It is very interesting! This goes back to three or four years ago, and, to tell the truth, it was Alexander Gdalievich Derechin [Deputy General Designer of RSC Energia –Ed.] who contacted our trajectory department about this issue. As you may remember, we [in Russia, in Roskosmos – Ed.] had a team of space tourists. For them, getting to ISS as quickly as possible was very important, because flying for 50 hours in the limited space of Soyuz spacecraft (here is a picture, half a cubic meter per person in the descent module alone, and 1.2 cubic meters if you add the orbital module); I think you’ll agree, that this is not easy, especially for women. I recall that Anousheh Ansari experienced some problems, it was very difficult for her to get through these two days. Here, for example, a picture from a presentation, which gives you some idea of the volume available inside Soyuz. As you can see, these guys feel really cramped, especially if these are big guys. And just imagine, that they have to stay within this volume for a very long time. During my trips to the launch site I often spoke with our cosmonauts (with Pavel Vinogradov and Alexander Kaleri) about this problem. They strongly believe that if there is an option of getting there quicker, we should grab it.  

As a matter of fact, at the very beginning all the first dockings were carried out as “quick” dockings, both in our country and in the United States. We recently celebrated the 50th anniversary of the mission of Vostok-3 and Vostok-4 spacecraft. That was the first joint mission, where at first one spacecraft was launched, and then a second spacecraft was launched into the same orbital plane, into an orbital position close to the first one. That was the trajectory profile we used in the Soviet Union. We took advantage of the fact that we had two launch pads located close to each other. Launched into an orbit with a period which is a submultiple of 24 hours (there is such an orbit with an altitude of about 200 km) was the first spacecraft, and in exactly 24 hours this spacecraft passed over the launch pad of the second spacecraft. It was at that moment that the second spacecraft was launched, and both spacecraft found themselves in close proximity to each other. It was not exactly a quick docking or a quick rendezvous, it was the so-called direct orbital insertion. Americans also chose to follow the path of quick docking profiles. It should be mentioned though, that their launch pad is very conveniently placed – they had two opportunities per day for launching spacecraft into the same orbital plane. How did they do it? The latitude of their launch pad is 28.5 degrees. First launched was a target vehicle that was put into an orbit with inclination of about 28.9 degrees in the ascending part of the orbit. Then, after about one orbit, this time in the descending part of the orbit, the launch pad at the Cape Kennedy [Canaveral – Ed.] was overflown by the target vehicle. And it was at that moment that the tracking vehicle was launched. They used Gemini spacecraft as the tracking vehicle, and the third stage of the Agena rocket as the target. In this way, in 1965-1966 they carried out a very intensive program of six launches and fully developed the docking procedure. That was the experience that they later used in the lunar program Apollo. The flew to the Skylab space station three times, using in those cases a 6-orbit rendezvous profile with the docking 8.5 hours after the lift-off. It should be said that time record for a manned docking [for the total flight time of a manned spacecraft from lift-off till docking- Ed.] also belongs to the Americans.  

History tends to be forgotten. It’s been 47 years since a manned crew performed a docking 94 minutes after the launch [what is meant here is Gemini 11 commanded by C.P. Conrad – Ed.].

We had about four missions [using the quick profile – Ed.]. And we were close to breaking this record. Let me remind you. In October 1967 there were two Kosmos missions - Kosmos-186 and Kosmos-188 [Unmanned versions of Soyuz spacecraft – Ed.]. The docking occurred seventy seven minutes after the launch of Kosmos-188. In half a year, in April 1968, Kosmos-212 and Kosmos-213 were launched. The docking occurred 47 minutes after the second lift-off or 38 minutes after the orbital insertion. As a matter of fact, this is an absolute record! Next, there was G.T. Beregovoy’s mission, who, unfortunately, could not complete the docking, although his spacecraft got as close as 200 meters from the target in less than an hour [the plan was to rendezvous his Soyuz-3 spacecraft with unmanned Soyuz-2 – Ed.].   He had been supposed to dock at an earlier phase in flight than the American C.P. Conrad and break the record.

Those were the first dockings. After that, began the era of missions to and dockings with the orbital stations. For this purpose, one-day rendezvous profiles were adopted. One-day profile was less strenuous and was used from 1969 to 1986 until Mir space station was launched. But it should be noted that there were differing opinions about the one-day profile. It is believed that it takes about two or three days for a cosmonaut to adapt to zero gravity. And after one day in space, just before the docking, cosmonauts experienced the most critical period of adaptation to zero gravity. And it did not always happen that cosmonauts could switch to manual mode [of rendezvous and docking control – Ed.] and properly complete the docking operations.

V.: After one day? 

M.: After one day. You may remember that we had several docking failures when the one-day profile was used. In 1986 we launched the Mir space station. A decision was made to try not to maneuver the station. Up until that time we always corrected the space station orbit for the spacecraft docking per one-day profile. Two weeks before the launch we corrected the space station orbit and phased it [what is meant here is relative angular positions of the spacecraft and space station in orbit – Ed.]. But I’ll return to that later. When we switched to two-day profile, we thought that Mir space station, being very heavy, would never maneuver before the launch of a spacecraft. Ever since then we have been flying (1986 through 2012) for 26 years using the two-day profile. The question arose why should not we try to dock earlier? For the sake of example, I have the two-day profile shown in my presentation.

V.: When the question of an earlier docking arose, it was clear that it was not to be a return to one-day profile; one should use the experience gained earlier, back in 1960s. Is it possible to dock after three or five orbits, that is, during the first day after launch, when the acute phase of zero-gravity adaptation has not yet set in? 

M.: You are right, Oleg. First of all, physicians believe that zero-gravity fatigue and decline in physical condition begin somewhere after the sixth or seventh orbit. It is at that moment that fatigue and depression set in. Right after the launch, on the other hand, and that’s what I’ve been told by cosmonauts who actually flew in space, their mental state is close to euphoria. After many years of waiting for the mission, and the pre-launch commotion, they finally go up … and find themselves in zero gravity. The words they actually told me were: “After the launch you get a feeling you can take on anyone!” Indeed, at that moment cosmonauts do feel a surge of energy. They don't care about zero gravity. Later on, yes, the fatigue sets in, the routine begins, the spinning starts.

You may know that our spacecraft must turn in the Sun [what is meant here is spinning the spacecraft in orbit about its transverse axis pointed at the Sun – Ed.]. Coriolis force appears. If you are a rookie, you start looking into the window, and your fatigue grows. And you end up with severe fatigue and complete loss of working ability. That is why it is so important to complete rendezvous and docking within the first six orbits.

So we defined the time constraints – we had to dock before crew fatigue sets in. On the other hand, there is another constraint – visibility zones of the ground tracking stations, within which we can work with the station. Understandably, after the breakup of the Soviet Union the number of silent orbits where we cannot uplink commands to the spacecraft has increased (because the number of tracking stations went down). The last obit where we still have a more or less good 12-13-minute communications zone, and where we still can send commands and speak with the crew, is the fifth orbit. This means that the rendezvous is to be completed in five orbits and no more. Initially, all our designs of a ‘quick’ profile were based on a five-orbit rendezvous. The so-called five-orbit profile was developed. We were developing it for about two years, wrote technical resolutions, spoke to our subcontractors. There was a lot of routine work. We had to persuade many people, gradually winning them over. Just about over a year ago we came to the conclusion that the five-orbit profile can be implemented. Before we could use it on Soyuz, naturally, we had to try it out on Progress. That was a very sound approach. Progress is an unmanned analogue of Soyuz, which enables us to test lots of things. But in this particular case we found ourselves in difficult situation. The five orbit profile already existed on paper, every detail was written up, but it turned out that it could not be implemented for the unmanned vehicle. There was not a sufficient margin to cover some commands [to perform a certain list of activities, including generation of commands – Ed.], in this case, for teleoperator mode. There was virtually no visibility zone during the sixth orbit. This problem wouldn't occur on Soyuz, but we had to try the procedure out on the unmanned vehicle first. But it couldn’t be tried out on the unmanned vehicle, because we didn’t have a sufficient zone (of communications coverage – Ed.). All the operations had to be completed before the fifth orbit, which meant reducing the phase range.

So, now we come to the notion of the phase range. As I already said, in recent years we've been flying using a two-day profile, and we had the phase range of 150 degrees. What is the phase range? The initial phase angle is the angular distance between the spacecraft and the station at the moment of the spacecraft orbital insertion. The phase range includes all the acceptable [values of – Ed.] initial phase angles. And to implement any rendezvous profile you have an optimum initial phase angle and plus or minus one-half of the phase range. For the two-day profile this range is about 150 degrees. For the five-orbit profile this range is about 35 degrees. This is significantly smaller than in the case of the two-day profile. But the experience of trajectory planners enables them to calculate the ISS orbital re-boost maneuvers in such a manner as to assure the required phase angle by the scheduled launch date. If we had reduced our five-orbit profile to four-orbit profile, then our phase range would have been not 30-35, but just 15-20 degrees. The number of opponents of switching to the quick profile would have grown many times over. They would have said that providing the required phase angle with this level of accuracy is too complex a task.

About a year ago, I and Yuri Borisenko, deputy head of Department 033, were sitting in my office thinking about how we could resolve this situation. And then, as it often happens when you are hard pressed, we hit upon an idea, which turned out to be fruitful. Let me explain the gist of it. Usually, after the launch of the launch vehicle we need at least an orbit to measure the actual trajectory [its parameters – Ed.]. This means that a whole orbit is lost for phasing, that is, the phase range is reduced! A decision was made, rather than to wait for a whole orbit, to use the nominal value of the orbital insertion vector to calculate the first two phasing burns in advance. In that case, we don’t loose the first orbit for phasing and the phase range is not reduced. Such an approach to the rendezvous task was used for the first time. This decision ran contrary to the main rule: first launch and take measurements then perform burns. What was being proposed now was first perform burns, then take measurements, and then make corrections. We added two corrective burns between the second and the third orbits to account for the actual trajectory. And finally, after the far approach flight phase, the autonomous flight phase begins, which had been successfully used for the last 26 years, and which is not changed in our rendezvous profile.

Actually, we stuck together these two options: a quick far approach, and then, the tried and true autonomous flight phase, which remains unchanged. This way, we made it to the required four orbits, even a little less than four orbits - 5 hours 40 minutes - 5 hours 45 minutes, while preserving the phase range of 35 degrees. That’s the gist of the idea.

V.: And what about the international partners? It’s the international space station, and flying onboard Soyuz are not only Russian cosmonauts, not only tourists, but also American and European astronauts. How difficult was it to get their approval for this profile? Were there among them any opponents of this profile or did it immediately win their support? 

M.: That’s a very difficult question. First of all, we have not yet launched a single manned spacecraft using the quick profile. We have conducted three successful experiments, I would even say, three and a half. Because we started our work back in April of the last year on Progress M-15M. On Progress M-15M we tested the feasibility of performing the first two burns using the nominal orbital insertion vector. Then, based on the actual state vector we performed corrections, although further rendezvous was conducted according to the standard two-day profile. On Progress M-16M, Progress M-17M and Progress M-18M we already tried out a full-fledged four-orbit profile. And here, neither Americans, nor Europeans had any problem with that, since it is our spacecraft Progress. They did have some objections, because in order to assure the required phase angle the launch date had to slide plus or minus one day with respect to the initially planned date. But these issues were resolved in the regular course of work, somehow everything turned out to be according to plan. Nobody was really concerned about the unmanned cargo vehicle. But when it came to launching Soyuz, they started asking questions: “How are you going to assure the phase angle? This is a very complex program! What if it fails?”

What to do we say to them now? If you launch Soyuz using a quick profile, you have an optimum phase angle of 30 degrees. If before the launch you had some space debris flying by, you needed to perform avoidance maneuvers, and your initial phase angle went beyond the acceptable range of 35 degrees, then you’ll always have the opportunity to launch using the two-day profile. To the 30 degrees you add 360, you get 390 degrees and without any problems you fly the two-day profile. As the players of the preference card game say: “the table was not damaged”!

You can quietly continue to perform rendezvous per two-day profile. It was not abolished and cosmonauts were trained to fly it. We did our best to explain to our US counterparts, from trajectory standpoint, that this is feasible. Then the Americans tried a different tack – that it might not be good for the cosmonauts, that after four orbits cosmonauts won’t feel very well, etc. Although, it seems to me that they are not quite sincere here. Why? Because they already flew using a quick three to five orbits profile on Gemini, they flew to Skylab in six orbits, rather than in four orbits as in our proposal. So we proposed to them: “listen up, guys, let’s fly at least once using this four-orbit profile, then we’ll meet a year later and talk about it". That’s the kind of questions our partners have.

At the level of specialists, our counterparts, after the docking of Progress-M-16M, we received an enthusiastic feedback. One colleague from ESA sent us a letter (and it was at the time of London Olympics): “Russians must be awarded a gold medal for the fastest docking!” There you are.

V.: And what additional measures need to be taken onboard ISS to support a quick docking profile? 

M.: We need to provide the required phase angle. If we don’t do anything, then, on a specific date we won’t have the required conditions for launch even if we use the two-day profile. Therefore, knowing the mission plan for a year, we prepare the best angle by performing the ISS re-boost maneuvers. If you spread them over the time in the right manner, then by a specific date you provide all the conditions necessary for launch. In addition to this, the maneuvering provides conditions not only for the launch of Soyuz, but also for de-orbiting of both the unmanned vehicles and Soyuz. With Soyuz re-entry being the most critical operation. Because it involves search-and-rescue people, they need to be provided with proper conditions for rescuing the crew above everything else, etc.

That is, these orbital corrections support everything, the entire chain of upcoming events. What am I getting at? In any case, be it two-day profile, or quick profile, we need to perform maneuvers anyway. Americans raise objections that meeting such stringent phase requirements might necessitate too many orbital corrections of the space station. I hasten to assure you that the number of corrections didn’t increase a bit, it even decreased a little. While in the last year and in the year before the last there were 18, 20, 21 of them, for this year we plan 17 corrections.

They also had concerns that some braking correction maneuvers might be required. So let me tell you this: we are not going to make any braking correction maneuvers. We fully appreciate the fact that they are not the best thing to do. All the correction maneuvers will be boosting the space station velocity. In other words, we provide the required phase angle within the framework of the orbital correction strategy planning. If, for some reason, we are suddenly not able to meet these conditions, then, let me say it again, and it is written in all of our documents, we are going to perform the rendezvous using the two-day profile. So why should we abstain from the quick profile, if it does not hurt anyone? You either rendezvous directly using the two-day profile, or you rendezvous using the quick four-orbit profile. And maybe, with some low probability, let’s say 5%, you might run into a situation where you’ll have to switch to the two-day profile. So, let’s try and fly the quick profile. That’s to answer your question about additional measures.

Let me repeat it once again, the art of trajectory people both at MCC and at our Energia [RSC Energia – Ed.] makes it possible to successfully provide the required phasing conditions. Let me give you and example. The last orbital correction before the March mission will take place, I think, on March 22. If something happens before March 22, for example, a piece of space debris will fly by, and we will have to perform a collision avoidance maneuver, we’ll just delete this correction maneuver in March. And we'll still end up within the specified range. Not at all a zero range, but rather ±15 degrees. If between March 22 and 28 some debris appear, we, of course, must perform avoidance maneuver, but by doing this, we will not get out of the optimum phase range. In other words, this problem can be solved through optimal distribution of corrections (that’s what I was just talking about).

V.: Thank you very much. The next question. On March 28, it will be the first time for the manned spacecraft, Soyuz. Does the crew need some special training for the quick docking? Did they specially select a cosmonaut who can perform this? 

M.: Well, let’s go back a little. In 2011, when we still had no positive experience, nor did we have this 4-orbit profile, we already started pushing for permissions. And everybody turned our proposals down. Among all the others who turned us down was also IMBP (Institute for Medical and Biological Problems). They sent us a letter, saying that “there are some issues with spacesuits, with life support:   hardware is one thing (excuse us, you Progress-lovers), but human being is quite another”. And then, on December 27, 2011, I remember it very well, I have a good memory for dates, we had a meeting at IMBP. Representing Energia were the head of Scientific and Technical Center 20C Nikolai Petrov, cosmonaut Pavel Vinogradov and yours truly. We spoke with IMBP senior managers. And we managed to win them over to our side! They gave us their go-ahead for developing the quick profile using unmanned vehicles.

As for the possibility of implementing the quick profile on Soyuz, it was decided that:

1. there shall be 2 Russian cosmonauts,

2. there shall be one experienced cosmonaut (with spaceflight experience),

3. Special drugs shall be used.

I think, this is only fair. Everything conspired to probably make the man who so actively supported us, Pavel Vinogradov, the first tester of the quick profile.

V.: As fate has willed it, he was chosen? 

M.: Let’s say that we did our best to make the fate will that he be chosen. It’s probably because if you really want something, you may eventually succeed.

V.: And what about the scope of training, will it be expanded? When will the training sessions start and when are they to finish? 

M.: The first training session will take place on Friday, February 22 [the interview was recorded before that date – Ed.], that is, a little bit more than a month before the launch. Training specialists have already tried these modes out. We sat down and had a talk with them. In principle, everybody seems to be more or less happy. I’ll let you in on a secret: I, together with Pave Vinogradov and his flight engineer, worked out the four-orbit profile as far back as June of the last year. Cosmonauts with flight experience will understand me. What is the procedure now? The crew goes up, performs the first two maneuvers, then spins up, and then the crew doesn't do anything for a very long time. They get bored. Not only do they get bored, they experience hardship. The cramped space, and on top of it, the spinning to track the Sun, which affects the human body, especially in the case of a rookie. All-in-all, they probably don’t feel very well after a day.

While in the new profile everything is stitched together so closely, they just don’t have time to get bored. They’ll be monitored all the time, they’ll have to be alert all the time. And once again, if you are busy working all the time, as Kamanin said (I read his memoirs), you don’t get tired. Cosmonauts don’t get tired – they are busy working all the time. And there is one more problem brought up by the Americans – the long launch day: From wakeup to lift-off, from lift-off to docking and up to the opening of the hatches and transfer into the ISS. We showed them that the launch day in the new profile is no different from the first launch day in the two-day rendezvous profile. Well, maybe it differs by one additional hour. But this is acceptable. Maybe we could work on it more to further improve this profile. So that we could get there even faster. Something along these lines.

V.: Raf, you mentioned that the four-orbit profile is only the beginning, that an even quicker docking is possible. Just let me make sure I got you right – there are going to be a three-orbit profile and a two-orbit profile. And development tests, are they going to be run on unmanned spacecraft? 

M.: Well, about development tests, I can tell you right now – it stands to reason to test all modifications in the rendezvous profile on unmanned vehicles first. The unmanned spacecraft makes it possible, in case of a contingency, to safely switch to the two-day profile and see it through to the docking, that is, to accomplish its main mission, which is to deliver cargo to the ISS. In this context, it’s only natural that any task will be first tried out on unmanned spacecraft whenever we introduce a change into the system.

Now, about the possibilities. The Olympic principle – faster, higher, stronger – still stands. Well, in our case, it’s faster. Which means that while in the past it took us 50 hours to dock, now it’s 5.5 hours. We made it 9 times faster! And there is one more advantage (that’s a remark for those who are skeptical about the quick profile) –our three unmanned spacecraft saved about 20 kg of propellant each. And this is about 7 to 8 percent of the total propellant used by the spacecraft for a rendezvous. This means that besides reducing the flight time, we have a tangible gain in propellant. Where does this gain come from? That’s easy to explain. In contrast to the usual missions, where we has to perform 7 attitude control maneuvers: spin-up, OCS, once again spin-up, again OCS etc., in this case we only need to establish the OCS attitude control mode once, immediately after orbital insertion and then fly maintaining this attitude up to the moment of docking. That’s where these savings of about 20 kg come from.

V.: If you multiply 20 kg by 6 unmanned and 4 Soyuz spacecraft, we get 200 kg per year. This figure looks more significant. 

M.: What we are mostly concerned about is this. We improve Soyuz performance and this enables Soyuz to carry out dockings at higher altitudes. At present, we limit the docking altitude and, therefore, the altitude of the ISS flight because we need to make allowance for contingencies and be able to perform re-docking. The additional propellant savings will enable Soyuz to fly higher. This, in turn, will satisfy one more demand of the Americans, who complain that they cannot at the moment fully use the propellant of the ATV (European cargo spacecraft). If we can raise the ISS orbit, we automatically will be able to use all of the ATV propellant for re-boost, that is, here we have a fully integrated solution for the problem of using all of the ISS resources. But that was just a side remark.

Now, about improvements. Having analyzed the 4-orbit profile, we see that within the framework of the same profile, with no changes to the autonomous flight phase, we can successfully accomplish a rendezvous in as little as 3 orbits. That is, we can further reduce the flight time to the ISS by 1.5 hours, and make life easier for the crew. What do we need to achieve this? Actually, this requires a new launch vehicle. And it isn’t somewhere far off in the future. It’s not a fantasy. What we are talking about here is sometime around 2014. We are switching to a new launch vehicle with digital control system and with 5 to -5.5 times better accuracy of orbital insertion. This will allow us to delete corrective burns in the 2nd orbit. And to immediately start on the autonomous approach phase, right after the two phasing burns, which we perform during the first orbit. According to our calculations, this will reduce the phase range a little, but not by much. Instead of 30 – -33 we will have 25 – -28. We do have such option.

If we are delving deeper into the subject of improving the quick profile, we have done some more studies. They assume, though, that we change the existing autonomous flight phase, and in that case we will be able to accomplish docking in as little time as one orbit.

On June 17, 2010, we had a meting of our company’s Scientific and Technical Council, where we described in the detail the approach that we are going to use. It’s not a fantasy! This is not a trick! That’s rigorous, straightforward, engineering analysis. This is feasible.

V.: Actually, to an outsider, this seems fantastic! One, two or three orbits after the launch, the cosmonauts can dock and hug each other. This is an important psychological factor. Then, if there are some problems onboard the space station, bringing help on an unmanned or manned transportation spacecraft will take less time. There will be no need to wait for two days for the emergency aid to arrive. Everything can be organized faster. This is indeed a great breakthrough. Cosmonauts are looking forward to meeting their comrades and colleagues. I worked at mission control for many years. And during the two days of free flight, there is a lot of talk: “how are our colleagues doing, is everything all right, how successful was their maneuver”. That is, for those two days their lives revolve around this subject. If cosmonauts can have the docking on the day of the launch, and they can immediately receive gifts from their friends and family, this will be a serious boost to the morale of the crew who had been staying in orbit for several months. 

M.: Oleg, let me add one more thing in connection with this. Recently, I've been hearing a lot of talk about Soyuz being obsolete, and that conditions for cosmonauts there are not very good. This is true, if you plan to fly for two, and, sometimes, for three days (in case of a contingency). But if you are going to fly for one, two or three hours, you’ll probably be able to bring yourself to sit a little on the couch waiting for a quick docking. The spacecraft is far from having outlived its usefulness. There is still room for further development and improvements there. You must admit that it’s very interesting to see what result (in terms of time required to accomplish a docking) we can achieve. Ultimately, this figure – 94 minutes (US record) – is our target. Sure enough, special conditions were set up for that particular mission, and now we are going to fly to the space station, which flies independently of the newly launched spacecraft. But if a one-orbit rendezvous is feasible, why shouldn't we try.

V.: As far as I know, the orbital altitude then was lower than the current orbital altitude of ISS. 

M.: They were inserted into virtually the same orbit where the target was flying. Those were very different conditions. Let me say it again, our unmanned cargo spacecraft deserve to be entered into the Guiness Book of Records – they reached ISS in 5.5 hours. If everything goes well, in March our manned spacecraft will reach ISS 5 hours 40 minutes after the lift off. For now, the record [the minimal time – Ed.] for reaching an orbital station is 8.5 hours. This record belongs to an Apollo, which flew to Skylab.

V.: Where else could the quick profile be used, besides rendezvous with ISS.  

M.: A good question. As you know, we are now developing a new spacecraft. This spacecraft is supposed to be able to fly to the Moon. So, if you take a spacecraft weighing 20 metric tons and put it on one rocket, according to current designs this rocket must have the mass of at least 100 metric tons. This is a launch vehicle in the same class as Energia launch vehicle. Today, it’s a great challenge to revive that technology and build this kind of rocket. Yes, one could say that nothing is impossible. But let’s be realistic. This is a very difficult task!

And now imagine, that instead of one heavy rocket we have two rockets with upmass of 60 metric tons each. One might say that development of such a rocket is close at hand. It could even be built on the basis of those rockets that are currently available. So, imagine that you launch one rocket, and exactly 24 hours later you launch the other spacecraft. And you complete the docking. Effectively, you get a 120-ton rocket, which you can fly wherever you like. Here is a good reason for using a two-launch profile. You can't afford to go slow with the docking, because the upper stages are more efficient when they use cryogenic propellant components: liquid oxygen and liquid hydrogen. This will give us a higher delta velocity due to a higher specific impulse of the propellant. Therefore, we need to dock as quickly as possible. And immediately after the docking, after 2 or -3 orbits, perform an acceleration burn towards the Moon. And we can solve this problem now. We are developing the solution on our Soyuz and Progress spacecraft. And later on it can also be used in our lunar projects.

V.: I would like to come back to our crew. I just want to make sure. Pavel Vinogradov was an advocate of quick docking from the very beginning. It was clear that he was willing to work on this problem. Therefore, he is probably the best first cosmonaut to perform the quick docking. But are the other cosmonauts willing to use the quick profile after Pavel Vinogradov? By how much is the time needed for training increased?  

M.: Well, I can say the following. First of all, the Cosmonaut Training Center has set up a trainer, which makes it possible to simulate the entire profile – from orbital insertion to docking. Secondly, the scope of training has increased. But in the past the cosmonauts were training separately for the orbital insertion phase and rendezvous phase, and now the rendezvous phase does not change. It remains the same both for the two-day profile and the quick profile. Strictly speaking, the difference lies in the training for the first two orbits. Does this mean additional training sessions? Yes, probably, it does. But although the crew has a tight training schedule, allocating some additional time is doable. I would also like to say that after we had successfully completed missions not even of the 3, but of the first two unmanned spacecraft, we clearly saw that the quick profile was now favored not only by the senior management of our company (they always supported us), but also of the Roskosmos. We were given a recommendation to try to use the quick rendezvous profile in as many launches in 2013 as possible. Let’s hope that this trend will continue.

Actually, our original plan was to use the quick profile for Soyuz only. But the senior management looked into the matter and found certain advantages in using the new profile for unmanned spacecraft as well. This profile requires less resources, there is no need to reserve the ground tracking stations for 2 days, etc.. This also translates into some savings.

V.: Has anybody else started the training, besides Vinogradov? Can you name cosmonauts who are already in training for the new profile? 

M.: Yes, Vinogradov’s backup Oleg Kotov with his team, they are going to fly this autumn. They’ll fly in the autumn. Oleg is already in training. I think, theoretically, Fedor Yurchikhin, who is going to fly in May, is already prepared. But immediately after the launch of the Vinogradov’s crew, Yurchikhin and his team will begin training. By the way, Yurchikhin will be the only Russian in the crew, the rest of the crew will be two Americans.

V.: And does the quick profile require any assistance from a second crewmember? Or can the commander do everything alone? 

M.: As a matter of fact everything is automated. The flight engineer is responsible for monitoring: verifying whether the settings for the first two burns have been entered correctly, because, in contrast to unmanned spacecraft, the crew will be entering them manually after boarding the spacecraft. That's more expedient and convenient, and it only takes about 4 or -5 minutes. That will be the operation which will have to be performed. And from that moment on, the onboard computer takes over. MCC, based on the measurements of the first orbit, sends to the spacecraft the actual state vector existing after the orbital insertion taking into account the first two burns, and after that the onboard computer (with new software) itself calculates corrective burns, and thus automatically takes the spacecraft to the space station. It’s only natural that all these operations will have to be monitored by the commander. It seems that there really isn’t much work for flight engineer. One Russian crewmember can handle this task.

V.: As a backup for automatic docking of the unmanned spacecraft there exists a so-called TORU mode (teleoperator control mode – Ed.), where the crew onboard the space station takes over the control of the docking process in case of a failure in the KURS system (relative measurements system – Ed.). In case of a manned spaceflight the main docking mode is automatic where the crew is not involved. The backup mode is manual docking performed by the crew who have just been launched. As we understand, the crew must be in good condition, they have not yet been affected by flight fatigue. And yet, have you thought about playing it safe and making the TORU mode a backup mode for manned spacecraft in case of the quick profile?

M.: This option is not considered now. First of all, I’m a trajectory specialist. But I understand the problem. That would be difficult. The spacecraft, its software would have to be completely reworked. It seems that the solution here must be as follows. The commander is fully responsible for the crew. He must oversee everything, he must understand his own condition and feel the condition of his crew. If he sees that for some reason the crew is not capable of completing the docking in manual mode, he must report about this to the ground control, and the ground control will set up the docking in two day’s time. During a contingency at any phase of the quick docking we switch to the two-day profile. The amount of additional propellant at stake here is 70 kg. This propellant is available and is written up in the rendezvous propellant budget. That’s how this problem will be solved. One may ask a counter-question. What if we had a contingency when using a two-day profile? What then? That meant putting off the docking for one more day. So the quick profile also saves us resources.

V.: Thank you very much for the interview. We hope that the quick docking performed by the crew headed Pavel Vinogradov will be successful, and that this rendezvous profile will be used in the RSC Energia lunar program and in other projects of our company. 

 

M.: Thank you. Thank you for the opportunity to address the space buffs who are interested in this subject, and who most certainly visit your web site. Maybe, they'll have fewer questions, more understanding, and there will be fewer skeptics. There will be more people who support our idea.

Интервью с Р.Ф. Муртазиным
Интервью с Р.Ф. Муртазиным

Using Pre-flight Data in Quick Rendezvous of SoyuzTMA-type Spacecraft with ISS

Presentation materials for the R.F. Murtazin’s lecture at the 37th Korolev Lectures at Bauman Moscow State Technical University in January 2013.

 

 

 

 

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