133 – The Space Shuttle (Part 2, Operations)

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This is the second of two episodes on the the Space Shuttle’s systems and operations. We talk to Davide Sivolella, an aerospace engineer who has written a quite technical book on the shuttle. In this episode we talk about some of the shuttle’s operations, including launch, landing and proximity operations in space.

A related omega tau episode is episode 43, Flying the Space Shuttle.

25 Responses to 133 – The Space Shuttle (Part 2, Operations)

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  3. Geoffrey says:

    Just listening to this podcast. Listened to part one past weekend. Standard as high as usual. You always show a genuine interest in the topic.

    By the way, I seem to recall you talking in an Omega Tau episode some time ago about the unique updrafts over the Andes. I thought of this when listening to a NY Times podcast a few days ago when they covered a special glider project aiming to reach 90,000 ft. It was in the 22 Oct 2013 release of their Science Times podcast. Thought you might like to be aware of the project. I know you’ll be interested.

  4. MaNo says:

    Yes, I am aware of this high-flying glider project. In fact, I had asked them already twice about a podcast. But they never reacted :-(

  5. Robert Coates says:

    Wow – even more interesting than Part 1. Grazie, Davide and Vielen Dank Markus! Regards, Rob, Perth, Western Australia.

  6. MaNo says:

    Thx :)

  7. Rick says:

    Thanks again for another fascinating insight into the space program.

  8. Jonas says:

    Just wanted to say a big THANK YOU for these two REALLY great episodes, Markus! Your podcast has made my life better :-)
    And Davide, consider your book bought a couple of times! Great work!

  9. MaNo says:

    wow, these are strong words, thanks :)

  10. Jochen says:

    Thank you again for your great work!
    I appreciated this second part as much as the first and would not complain about a few hours more… ;-)

    As almost always you asked the questions in a way, even a normally interested non-engineer is able to follow the topic and thinks by himself: „Oh wow, I didn’t know it before, but that’s exactly what I would have asked as well“… Not too geeky but detailed enough to learn more about the theme than in a normal TV documentation or similar.

    Thank you!

  11. MaNo says:

    Thank you (again :-)) for your nice words :-)


  12. Evan Stanbury says:

    I really enjoyed the podcast…
    One minor amendment: In discussing the kinetic energy of the space shuttle docking with the space station, the need for a gentle approach was mentioned. After all, the ISS was designed to be as light as possible, and an impact could damage it structurally or damage air seals.
    However, the discussion then diverted onto the immense orbital velocity of both the space shuttle and ISS – and what this does to kinetic energy when you square the velocity.
    However, the orbital velocity only matters if the space shuttle and ISS were on opposing trajectories – or both struck a “stationary” object.
    However, when they are on basically the same orbit, all that matters is their quite low relative velocity, not their orbital velocity around the Earth (or the even higher orbital velocity around the Sun or the center of the galaxy).

  13. MaNo says:

    Thank you Evan for your feedback. However, I think I have to respectfully disagree with your statement about velocities:

    Actually, my understanding is this: When two objects collide (or dock), the objects have to absorb the difference in energy between the two objects.

    The kinetic energy is calculated as W_kin = 1/2 * m * v^2. The difference in energy is W_kin_ISS – W_kin_Shuttle. So as you can see, the resulting energy does not contain the difference in speeds, it contains the difference of the squares of the speeds. So the absolute value of the speed does make a difference, even when the difference itself is small.

    My physics teacher (back in the day) always asked the following question: Which is the worse crash? Crashing into a wall with 20km/h or crashing into a truck that drives 80 km/h with a car that goes at 90 km/h. And even though the speed difference is smaller in the truck case, the energy that has to be absorbed by the car (and the truck, I guess) is quite a bit larger. So the truck case results in the worse crash.

    So because of the large absolute values of the speeds, it is my understanding that the relative speeds have to be *really* small.

    Or am I wrong here?

  14. Jochen says:

    I am a bit puzzled as well.
    I would agree with Evan and had the same thoughts while hearing the concerning dialogue. If your assumption is correct, a car crash at the equator should be worse than one near the poles because of the higher absolute kinetic energies, right? For my understanding too, the sheer speed difference should be crucial to the effects.
    I would be very interested in the physically correct answer!… ;-)

  15. MaNo says:

    Hm. The equator argument is a good one :) I will make sure I’ll ask a real/practicing physicist when I see one!

  16. Jochen says:

    Another argument: a piece of cake, thrown within the ISS from one astronaut to another, would have terrible effects on the receiving one?… ;-)
    (There should be no difference whether the masses collide in- or outside the space station as long as they have a relative speed?)

  17. Evan Stanbury says:

    I think most of the damage from the car colission at 90km/h comes from the bodywork hitting the tyres at a relative speed of 90km/h. This is often followed by the car striking the road at a relative speed of 90km/h (and then sometimes a guard rail or a tree at close to 90km/h).
    …but I’m just an amateur physicist (and an amateur driver).

  18. Maurice says:

    Again a great episode. I liked the comparison with gliders, even though this thing is like an elephant among the gliders.

    You gave even some nice tips on flight approach, which I will apply when I fly (a simulator) again.

  19. MaNo says:

    hehe :-)

  20. DeRei says:

    Thanks for many inspiring hours. Including these episodes.
    (although: my favorites remain the Apollo episodes), but:
    a piece of cake, thrown in the ISS…
    I think (see MaNo, Nov. 17th): we should compare E_kin before the crash, and after:
    Before: E_kin_ISS + E_kin_Shuttle, After: E_kin_(Shuttle+ISS) + Delta E
    After the event: the merged combination (Shuttle+ISS) travel together, lets say with velocity V_s. And Delta E is the energy to be absorbed by the structures/ is the “damage done”,…
    We see: one equation, but two unknowns: V_s and Delta E . Which fraction of initial kinetic energy is now in the kinetic energy of the combined system (m_total V_s^2), and which fraction is in the damage (delta E). We need a second equation. This is momentum balance: adding both momenta (m V) before the event must be equal to the momentum of the combined system m_total V_s after.
    Now we have the 2 equations for the two unknowns. And, after some algebra, we find, I trust (have not checked) indeed,
    that the delta E (energy available to do damage in the crash) only depends upon the relative velocity (V_ISS-V_Shuttle), not on the “absolute values” (??) of velocities.

    Still I would prefer to crash with 20km/h into a wall rather than with 90 km/h into a truck travelling at 80 km/h. But this not due to the direct damage done to the car body, but due to other effects following the crash, see Evan, Nov 20

  21. MaNo says:

    Thanks Detlev for your explanation. Indeed, momentum balance is the key to the problem. Somehow I (and it seems, others) always forget about that. By the way, the explanation by the two Methodisch Inkorrekt guys highlighted the same issue.

  22. Thomas Troendlin says:

    Many thanks for this episode to “Mano” and also Davide of course. After a short period of ‘not listening all episodes in time’ I started with the Space Shuttle episodes. And almost instantly I got regrets about my ‘behavior’ not to follow. Again many thanks for such a great work and such passion which your work clearly indicates. A funny thing is the correlation about the date of birth and the favorizing Apollo vs. Space Shuttle episode. Davide and you mentioned both you prefering more the Space Shuttle than the Apollo. As a matter of fact I´m born in 66 and got my first Space related books in the mid and late 70s so I´m kind of bound to the Apollo era.

    Nevertheless I remember very well when Crippen and Young started in the early 80s, it was amazing…
    Wish you happy holidays ..

  23. MaNo says:

    Thanks Thomas :-) I agree, the correlation between age and machine is probably true … I never saw a moon landing live. In my case, I guess, the fact that the Shuttle is (more like) an airplane probably also helps :-)

  24. Thomas Troendlin says:

    Hi Markus
    Thanks to the Amazon wishlist I´m now owner of Davide´s book :)
    Very interesting and full of details..

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