6 thoughts on “NASA And Commercial LEO”

  1. “In order to mitigate risks to the Station’s structural integrity, we recommended that the Associate Administrator for the
    Space Operations Mission Directorate ensure the risks associated with cracks and leaks in the Service Module Transfer
    Tunnel are identified and mitigated prior to agreeing to an ISS life extension”
    Doesn’t seem important.
    We need an artificial gravity station.
    Having an old ISS seems useful to determine how not to make future stations- ISS should become a museum in space {in higher orbit}.

  2. NASA says that their models and calculations indicate that there isn’t a problem so… Where have we heard that reasoning before?

    If there are cracks in a low stress area, why do they assume the one they can’t find is in the same place?

    The o-rings haven’t burned through yet, so they won’t.

    The foam hasn’t caused “serious” damage, so it won’t.

    I wonder if they can do a controlled de-orbit if they have to abandon it.

    1. There has, for many years, been a NASA working group in Houston trying to answer the question of deorbiting ISS. The last I heard out of it, in about 2017, was that they planned to bring all but two crew down to Earth, then start the procedure. The two remaining crew would, of course, be Russian. Using Progress module propulsion, they would bring the ISS down to a 100 km circular orbit, with the station in a minimum drag orientation. Then they would do a Progress burn to lower the perigee to 70 km, and turn the station to a maximum drag orientation before getting out of Dodge in a Soyuz.

      The target landing area would be the South Pacific, west of South America. The rule of thumb for satellites decaying from LEO is that 40% of their mass reaches the ground. ISS weighs in at 1,000,000 pounds, so we could expect 400,000 pounds of debris to hit the Earth. That’s significantly more mass than has ever been put into space in one vehicle, let alone come back from space.

      Entry debris models predict that the debris will be scattered over a downrange distance of 11,000 km (6,835 miles in real units – 2.44 times the maximum distance across CONUS). Any miss in entry interface location adds to the beginning and end of that debris footprint.

      It’s not an easy problem at all.

      1. This does sound like an exaggeration. Columbia weighed somewhere north of 180,000 pounds when it disintegrated over Texas, so that’s probably the closest analog. As far as I know, no one was killed, and no buildings were destroyed by pieces hitting the ground. And ISS is a far more fragile structure that a Shuttle Orbiter. I seriously doubt that anywhere near 40% of it will survive reentry. And even if it did, that’s less than 60 pounds of debris per linear mile. I bet it would spread out some too. What’s the area of your hypothetical footprint?

      2. “The rule of thumb for satellites decaying from LEO is that 40% of their mass reaches the ground. ISS weighs in at 1,000,000 pounds, so we could expect 400,000 pounds of debris to hit the Earth.”

        All of it reaches the ground. But seems the bigger it is, the more it hits ground in bigger pieces. {I wouldn’t follow the rule of thumb}
        Why not blow it up like you demolish a building?
        Or use the least amount explosives in the right places.

        I think dumb idea to de-orbit ISS- even if they knew how to do it.

  3. The report doesn’t really say anything new. I don’t think the Russians are going to do anything unless we pay them a bunch of hard currency. Rogozin is talking about simply giving NASA “responsibility” for the ROS whenever they decide to go. I’ll note that Cygnus will soon begin taking over orbital boost from the Russian segment so as to conserve Russian fuel. If it were up to me, I might rescue what I could from USOS and abandon the rest ASAP. The simplest process might be to move Node 3 to the nadir berthing port of Node 2. bring the Quest airlock forward, then detach at the juncture between Node 2 and Destiny. If Axiom Hab 1 wasn’t ready at the time, it’d be necessary to rescue the Z1 Truss and either the P6 or S6 truss segments too, by moving them to Node 2 before departure. This wouldn’t cost much (no new equipement) but it’d take a fair amount of EVA work. Pretty far fetched, I know.

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