Re: [Starlink] Starship's 4th flight test was magnificent

[Alexandre Petrescu <alexandre.petrescu@gmail.com>]

Le 10/06/2024 à 11:49, David Lang a écrit :
> Alexandre Petrescu wrote:
>
>> Le 10/06/2024 à 01:50, Dave Taht via Starlink a écrit :
>>>
>>> [...] seeing starlink maintain connectivity through nearly it all of 
>>> that plasma was amazing, too.
>>
>> I dont understand: the rocket body and head ('starship')  where 
>> connected to starlink sats during flight?  Wouldnt be enough to 
>> transmit straight to ground?  Or maybe the entire trajectory is too 
>> long too distanced from ground receivers?
>
> Yes, unlike other rockets, Starship has multiple starlink dishes on it 
> and has a high bandwidth connection through them during it's flight. 

Thanks, I did not know that.

A rocket using dishes to talk to sats sounds as a difficult means, as 
the rocket might turn around its short axis almost entirely during that 
hyperbolic trajectory (head up then nose down).   But ok, if it works, 
maybe taking advantage from some reflections from ground or other 
things, then all the better for them.

> There are only so many ground stations around the world for rockets to 
> talk to directly (and especially over the large oceans and Africa 
> there are substantial gaps in coverage)
True.
>
> the Starliner flight for example, only had telemetry and audio, no 
> video during it's flight.

yet the space shuttle was streaming videos of its take-off, without 
sats.  It was VGA resolution IIRC.

> The first Starliner test flight had the capsule misbehaving furing one 
> of it's gaps in coverage, which prevented controllers on the ground 
> from fixing the problem fast enough to salvage the flight.
I see, I did not know that.
>
> Also, during reentry, the plasma tha builds up blocks any radio down 
> to the ground, and with anything other than a starlink, it even blocks 
> radios up to satellites.

I did not know they use plasma to propel that rocket.  Actually I dont 
know much about how these things can be propelled, but I know that with 
these high speed objects photos one can see many things like 'aura' or 
'glow'  or even 'glory' in the certain light conditions.  If that is 
'plasma' then that could be it.

> A combination of the large size of the Starship, and the Starlink 
> capabilities makes it the first rocket that is able to provide live 
> feeds throughout the entire reentry.
This looks indeed great.  The time is so short during that flight that 
many things of the communication system have to be set up correctly.
>
> For this mission, there were some gaps in the coverage, Elon has said 
> they will be repositioning the starlink antennas on future flights to 
> eliminate the blind spots and get continuous coverage.

Looking forward to that.

Alex

>
> The Polaris Dawn private flights are doing experimentation with laser 
> tie-ins to the starlink constellations. NASA has the TDRS system to 
> provide near global coverage, see this video from Scott Manley on the 
> topic https://www.youtube.com/watch?v=42GpWBSwjZM
>
> David Lang
>
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