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Russians detach Pirs module in anticipation of Nauka arrival to ISS

With the engine problems of Russia’s new ISS module Nauka apparently resolved sufficiently for its rendezvous and docking expected on on July 29th, Russian astronauts today undocked the 20-year-old Pirs module, which then used its engines so that it safely burned up over the Pacific Ocean.

The article provides a nice history of Pirs, which was originally intended for Russia’s Mir-2 station, never built after the fall of the Soviet Union.

Pirs, meaning “pier,” traces its origins back to the Mir-2 space station — which was itself a Soviet project that’s design began in 1976. Mir-2’s long and troubled history would eventually find it in the early 1990s where major design changes to launch its various modules via the Buran space shuttle were underway.

Following the collapse of the Soviet Union in December 1991, Mir-2 emerged the following year as a four-module station — including a Docking Module, which would become Pirs. In 1993, Mir-2 officially merged with the long-delayed NASA/European/Japanese/Canadian space station Freedom project to become the building blocks of the International Space Station.

The module, which provided the Russian half of ISS needed extra docking ports, was originally expected to be replaced after about five years with a larger module, but this was never built.

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  • Jay

    I observed Nauka last night and a minute later the ISS passed by. Nauka’s brightness was about a -1, it was a dull red, but that color is from all the smoke and dust from harvest in this area.

    I wondered if there was KURS system on Pirs for docking or if they were using Zvezda’s? I did look it up and Pirs did have a KURS system, and they will use the KURS on Zvezda’s nadir port for Nauka. This brings up another question: is there a KURS system for each docking port or do they use only one system with multiple antennas and switch on the port’s antenna? I cannot find that piece of information.

  • Jay: As I understand it, each port should have its own Kurs system, with each approach module its own corresponding system on board. They work off of each other.

  • Jay

    Thanks Bob!

  • Edward

    Jay wrote: “I observed Nauka last night and a minute later the ISS passed by.

    At 5 miles per second (8 km/sec) orbital speed, Jay’s observation puts Nauka 300 miles ahead of ISS, more or less, depending upon the actual number of seconds in the observed minute. This may help us visualize the actual slow dance of docking to a space station, as opposed to the final steps presented by Kubrick’s interpretation of Clark’s book “2001: A Space Odyssey.” This particular dance is slower than most due to extra steps and a bit of a stumble early on.

    Here we are, in the next century (or did he intend it to be the next millennium?) and we are finally, if slowly, making Clark’s vision happen.

  • Jay

    Yes, I get to watch that dance all week between 9pm – 11pm. I just got done observing Nauka pass again and it took about 6 minutes. 30 minutes earlier ISS came over and will come over again in an hour.
    Nauka’s orbit is about 334 x 406 km at 51.6 deg and the ISS orbit is pretty steady at 420km (258 miles). I hope to see them closer together here in the next three days.

  • Jeff Wright

    Buran was what STS should have been.

  • Chris

    If you’re interested in how a capsule is maneuvered to dock with the ISS this Smarter Every Day explains the procedure. The episode has two halves. First is an interview with Scott Kelly and second, at about 5 minutes in, an explanation of the orbital mechanics.

  • Buran was what STS should have been.


  • Edward

    Good video. However, Destin Sandlin says, “We’re going to talk about rocket science, and it’s really not that hard. I promise.” This obviously comes from a guy who has never done the three-dimensional partial differential-equation math for rendezvous.

    As for the Buran, the Space Shuttle may have been a disappointment, and Congress should have insisted on an improved replacement right away (and should have insisted that Constellation and SLS were improvements, too). But at least we know that the Shuttle could be reused, could carry a crew, could do much science, could take a payload to orbit, could retrieve an orbiting payload, and could service an orbiting satellite. We don’t know that Buran could do any of those.

    If you want to compare the theoretical capabilities of the two, then the Space Shuttle comes off much better than the reality, as the fleet should have flown 64 times per year for twice the mission duration and carry more payload all more safely than it turned out to be able to do. Buran’s actual known capabilities are similar to the first unmanned Apollo spacecraft.

  • Chris

    Hi Edward . My submission of the video was for the explanation of the rendezvous only., I had not seen an explanation previously

  • Andi

    For those so inclined, here’s some of the math involved in orbital mechanics:

  • Jay

    I have used Bob’s site for years. I had quite a few questions in the past about trying to get 100 tons to orbit and he helped me out on the math. Good site!

  • Edward

    Sorry. I was teasing more than criticizing.

    Andi’s link gives some very nice basics, and don’t these basics look complicated?

    Location in elliptical orbit is very difficult to determine, which is one reason why it is difficult to predict collisions in orbit. Perturbation due to Earth’s shape is rather simplified, and there are varying levels of precision that can be employed using fairly expanded math models. Please note that orbital plane change needs a delta-v that is related to twice the sine of the angle of the change, which translates into a whole lot of propellant when making this kind of change.

    Finally, notice that orbit rendezvous is so complicated that the article does not provide math but only provides a single paragraph giving vague information on technique.

    These are only some of the topics in that link that I wanted to point out as being more complicated than presented. I once took a graduate level course that still didn’t have time to cover everything in enough depth. Those guys in the 1960s, such as Dr. Orbit (Buzz Aldrin) who began figuring out all this detail amaze me.

    I didn’t take the course on launch into an orbit or reentry from orbit, but wish I had. These are two more topics of great complexity and are fun to think about.

  • Edward

    Oops! Sorry, that is “Dr. Rendezvous.”

  • Col Beausabre

    Film from NASA of Pirs undocking and view from space of it burning up in the atmosphere

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