Return of the Soviet station. Analysis and documents
This is a continuation of the history of the Soviet interplanetary station, which will return to us again. Start here .
What I like about such discussions is that you can clarify a lot during brainstorming. And the new information is really interesting.
To begin with, Igor Lisov (a columnist for the Astronautics News magazine) correctly pointed out that in the last article I did not analyze the fate of all the objects that were in space in 1972. I will quote his analysis in full:
Following the launch of March 31, 1972, four objects were entered into the American catalog at once, and the fifth after three months.
5920 (1972-023B) - a third stage rocket "Lightning-M" gone orbit 01.04.1972
5921 (1972-023C) - RB start providing unit, left the orbit 04/02/1972
5922 (1972-023D) - upper stage, RCS = 8.3 m2,
de-orbited 02/20/1983 5919 (1972-023A) - Cosmos-482, RCS = 9.7 m2, de-orbited 05/05/1981
6073 (1972-023E) - officially considered to be a fragment of the launch vehicle, but probably is actually a spacecraft descent vehicle, RCS = 0.82 m2, is in orbit and is the hero of this article.
Thus, it is not the Soviet AMS as such that falls, but its descent vehicle. At least in the first approximation, it seems so.
With the first objects we, in fact, dealt with in the last article. The remark about the overclocking unit is also logical. Indeed, after the completion of the “L” block, it had to separate from the interplanetary station and leave the orbit, since it was very light / bulky.
The appearance of the object 6073 is much more interesting. The first TLE to it (which I found) dates back to July 5th. Three months after the launch of the station. This is close enough to the date the station reached Venus, if it went on an interplanetary trajectory. Its twin, "Venera-8", entered the atmosphere of Venus on July 22.
If we assume that the station worked all this time (and why not?), Being in solar orientation, then it can also be assumed that this division was prescribed in the station automatics as a reaction to the stopping of the transfer unit. For example, ending nitrogen stocks for orientation. The mode of operation in the Earth’s orbit should be different from interplanetary, and nitrogen goes much faster.
But this is only a version. Especially since there is information that contradicts it. Anatol Zach’s website has a snapshot of the station that astrophotographer Ralph Vanderberg gave him in 2011.
And according to him it turns out that the station is still not divided.
However, personally to me, the analysis of Igor Lisov seems more logical. It is backed by ballistic coefficients and an estimate of brightness. There is information that the brightness of the object varies slightly from phase. That confirms the version of the ball. But then it is not clear that he photographed Ralph.
Of course, this all changes little for us. We already waited for the return of the descent vehicle. He is now flying in space. The situation can only change with respect to the time of his return. The lander is both heavy and compact. Such weakly decelerated on the atmosphere. I conducted a past assessment based on the opinion that the station can survive the next peak of solar activity only after a noticeable apogee fall. After which a long time does not fly. The descent vehicle may reach the next peak. That is, the time of his life may increase by another 11 years. Next is unlikely.
However, in the history of the station there is a certain understatement. At the time of the last article I was working in the archive, and even though the main goal was the Moon, I also ordered several files of documents devoted to the study of Venus. Honestly, the goal was to search for documents that explained what happened to the overclocking unit. Then they had to figure out why he turned off ahead of time! Alas. That is what I have not found. The archive turned out to be only a technical task for the station B-72, two reports from the meeting of the state commission and one test parachute station. I put them in the link at the end of the article. The documents turned out to be interesting, if only by answering some of the questions asked about the landing of the station. Namely:
1. Without a parachute, the descent capsule will crash.
Not. Perhaps it will. You never know what happened to him over the years. But if judged solely by technical task, I personally find it unlikely.
Here is a quote from the statement of work:
Even at 70 atm, the calculated overloads were 100 g. With one atmosphere they should be noticeably higher. Given that landing on rammed sand and for the Earth is a permissible condition.
2. A parachute can be released. Suddenly there is a mechanical sensor?
Here, unfortunately, bad news. More precisely, I can not say what kind of sensor is used there. In the TK is not described. Only noted that the mechanism of ejection of the cover of the parachute container is changed. In the Venusian atmosphere, the parachute went out at an altitude of 64 km from the surface of Venus. This is about 0.1 atm, which corresponds to 16 km from the surface of the Earth. That is, if it came out, the height would be sufficient for braking.
Now a fly in the ointment. I discovered a parachute test report. direct link
To be brief, when a parachute was heated from stations B-72, it was found that at high temperatures it starts to burn and turn into a glassy mass with low strength. Which, of course, would be a disaster. But it was found that in the formulation of the experiment - a mistake, and a similar process occurs only in the oxygen atmosphere. In the carbon dioxide atmosphere of Venus, no oxidation occurs, and the parachute does not lose its strength.
In other words, in our atmosphere, due to the high temperature obtained when entering the atmosphere, the parachute may begin to oxidize, and during oxidation even more energy will be released. The thermal protection of the station must withstand, but the parachute will turn into a glassy mass. Alas, even if there is a certain mechanical sensor, then even when it is triggered, there may already be nothing to release.
3. We will not know where the station will fall.
Now - of course. But when the descent vehicle winds the last orbits around the Earth, the situation will change a lot. To begin with, the entrance to the atmosphere will occur in the perigee area. The longitude of the entry point can be understood by the coordinates of the longitude of the ascending node. In general, it will be possible to predict the last turns of the device from TLes. And, accordingly, to give the coordinates of entry into the atmosphere for the next few turns. Spherical lander - there is no aerodynamic quality. Because of this, the landing coordinates will simply be slightly offset from the entry point, in the direction of the turn.
So we will wait.
Materials 72 years, I made a separate link .