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Thomas Zurbuchen: Hubble is OK.

SpaceX approached NASA on whether a commercial crew could reboost Hubble...

Live now: NASA and @SpaceX leaders discuss the possibility of working together to boost @NASAHubble into a more stable orbit.
This was announced very quickly... conference is live now.

NASA, SpaceX, Polaris, Hubble representatives all participating


Incredible, keep it Hubble 👍

Surely not a Hubble servicing mission ?!

Learn how to do an EVA on Polaris Dawn and then put it to practical use on 2nd (or maybe 3rd?) Polaris mission?!
If they do it (which is a long pole), then I predict they dev an extensible docking adapter that is placed inside the trunk and pops out to dock with the Hubble adapter, perhaps with crew on EVA to troubleshoot.

Keep in mind that Crew Dragon's main propulsion is under the nose cone, so it would need to dock tail-first to reboost Hubble.
In this proposal, the center of the station does not need not be the center of rotation.

If the long tube-like section is supposed to be rotating, then what you are proposing is highly unstable, and likely can't work.

Referencing the intermediate axis theorem (Wikipedia link):

1. What appears to the space station would be (e1), and it tumbles end over end to create gravity. By itself that works.

2. Whatever unbalanced (or even balanced) mass you have jutting out from the side at the center of rotation becomes (e2), which due to even small sources of friction or torque, will cause that whole "arm" to start rotating perpendicular to the station portion (e1).

The result is a jumbled mess that happens before the Starship in your diagram tries to dock - which means it can't dock.

The intermediate axis theorem is real, and you can't keep assuming that masses will be fixed in place just because we want them to be. Masses in space will move based on ANY forces operating on them, in all three axis.

The best way to handle this is to have a 1st and 3rd axis of rotation be so overwhelming that the secondary axis forces can't overwhelm them. Which your design does not take into account.

Just to temper the excitement that's sending Space Twitter into a frenzy.....this word:

Today at 4:30pm ET, join me along with other science & industry leaders for a media telecon to discuss a new study exploring potential commercial space opportunities for #NASAScience missions:

So on Polaris Dawn they are going to study the possibility of a Hubble Servicing mission  :D
Blue Origin / Re: Blue Origin's BE-4 Engine
« Last post by Starshipdown on Today at 08:24 pm »
Something isn't quite right here. We were told that only one ATP was needed, so why now is it two?

I never heard anything about how many firings were required for the acceptance testing.  Could be one firing for a nominal flight profile, one off-nominal.

It's always been stated in the singular, like this one from August:

"The BE4 Flight engine #1 is in Texas for its acceptance firing." Not "firings", just "firing".

The closest to a plural is this one from a month ago:

"BE4 Flight Engine #2 is on the test stand in Texas for acceptance testing"

We knew by that time that the engines are put through a cold ATP (cryo and prop) and then a firing, but no indication directly of multiple firings.
Space Science Coverage / Re: NASA - Juno - Updates
« Last post by ugordan on Today at 08:21 pm »
A brightness-enhanced image showing the Jupiter-lit darkside illuminated as well

We've waited 20 years for this kind of an image... Europa is love, Europa is life  (this forum really lacks the emojis to express the kind of feeling one feels here, while at the same time focusing an immense amount of energy at blocking politically-incorrect terms (Europa fan-boy?)...)

You are forgetting history here. The retirement for the Shuttle was announced in 2004. At that time Boeing and Lockheed Martin had not merged into ULA, so they were flying their own rockets, but the U.S. was going to be without a way for accessing space with humans on a U.S. Government vehicle. Commercial options were not even a consideration back then.

So Constellation was the official effort to replace our LEO access ability with a new U.S. Government transportation system to send astronauts first to the International Space Station, then to the Moon, and then to Mars and beyond.

Yes, that's what I meant. After the cancellation of CxP, COTS and CCP were the commercial replacements for Shuttle. There is no government-owned replacement for Shuttle.

The SLS program was started in 2010, before it was known that commercial companies could develop and operate crew vehicles. So one of the mandates of the SLS+Orion was to serve as a backup for supplying and supporting the ISS cargo and crew requirements. It is in the legislation.

Yes, I know that LEO operations, and in fact all cis-lunar operations, were supposed to be part of the SLS mission plan according to the legisation. However, as soon as the final SLS design was revealed in 2011 all LEO operations went out the window. The SLS design does not lend itself to being useful for LEO operations in any meaningful way.


We don't need the SpaceX Starship to return to the Moon in a robust way. We could have already been returning to the Moon using Atlas V, Delta IV Heavy, Falcon 9/H, Ariane 5/6, etc. Once new launchers come online they can be added, but we have had the ability to return to the Moon without a SHLV since before the SLS was created.

I believe Congress wanted the US to have assured access to space using government-owned resources. And they wanted single-launch capability, instead of coordinating and depending on multiple commercial launches.

If you remember back to the time after Columbia, the consensus was that NASA had reached too far with Shuttle and that we needed to get back to basics for a simple, reliable, expendable, in-line launcher. The idea was that re-use and other advanced concepts put our astronauts at risk for not much return. I might add the fuel depots and in-space refueling can arguably be categorized as advanced concepts and risks that NASA wanted to minimize.

I think we can all agree that it took way too long for SLS to be completed. But it finally did get finished, and now Congress has the single-launch capability they wanted. Let's see what NASA can do with it.
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