I'd always seen the Proton rocket as one of the big mastodooons of the
rocket world. Needed to lift things like Zvezda etc.

Today, I learned its capacity to LEO is just 23,000kg to LEO while the
small Fakcon9's is 22,800. (some variants of Protol apparently to 23,700).

And even more surprised to find that Proton is hypergolic from sea
level. Would have expected it to be just a big Soyuz with Kerosene
engines.

Tried to read up on its history as an ICBM launcher. Have other
countries ever used hypergolics from sea level?

Was selection of hypergolics just to get something flying faster/cheaper/simpler (and it turns out it took over a decade to get
approved) ?

I know that ignition is simpler, but do hypergolics that are more then
mere thursters still need fancy turbo pumps and gasification prior to
reaching combustion chamber?

or is it really a question of low pressure spraying both liquids into combustion chamber and let the 2 mix and do their thing?

Would the Protol that launched Nauka today have been built at same time
as Nauka and just waited all these years, or would it be a recent build
once they were reasonably sure Nauka was ready?

And is this officially the last Proton to launch and no more to bve
built, replaced by Abgara, or is Angara still too immature to rule out
further Protol launches?

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In article <qV%JI.27680$[email protected]>,
[email protected] says...

I'd always seen the Proton rocket as one of the big mastodooons of the
rocket world. Needed to lift things like Zvezda etc.

Today, I learned its capacity to LEO is just 23,000kg to LEO while the
small Fakcon9's is 22,800. (some variants of Protol apparently to 23,700).

And even more surprised to find that Proton is hypergolic from sea
level. Would have expected it to be just a big Soyuz with Kerosene
engines.

Tried to read up on its history as an ICBM launcher. Have other
countries ever used hypergolics from sea level?

US. The Titan II missile, Titan II launch vehicle, Titan III launch
vehicle, and Titan IV launch vehicle all used hypergolic propellants in
their liquid fueled stages. But the US doesn't use them anymore.

China is still flying launch vehicles which use hypergolic propellant.
And because their original launch site is inland, this results in
boosters with some remaining toxic chemicals being dropped on villages.

Giant Rocket Booster Nearly Hits School
Sep 10, 2020
https://www.youtube.com/watch?v=U43khdtocpo

If you see a BFRC (big, fracking, red cloud), run away!

Was selection of hypergolics just to get something flying faster/cheaper/simpler (and it turns out it took over a decade to get approved) ?

Hypergolic propellants are super reliable to start. And you can easily
find hypergolic propellants that are storable at room temperature
(unlike the LOX oxidizer used in the Atlas missiles). Hypergolics were therefore a "good" choice for missile propellants. But, the US quickly developed solid rocket boosters which are also super reliable to start
and have none of the downsides of hypergolic liquid propellants (e.g.
toxic and/or corrosive). The Russians took much longer to develop solid
rocket boosters to use in missiles.

I know that ignition is simpler, but do hypergolics that are more then
mere thursters still need fancy turbo pumps and gasification prior to reaching combustion chamber?

Yes. Look at the Wikipedia pages for the launchers I mentioned above
and then click on the links for their first stage engines and you'll
find turbopumps.

or is it really a question of low pressure spraying both liquids into combustion chamber and let the 2 mix and do their thing?

Yes for vacuum optimized, pressure fed, engines. No for sea level
engines which typically need turbopumps to obtain the necessary
combustion chamber pressure.

Would the Protol that launched Nauka today have been built at same time
as Nauka and just waited all these years, or would it be a recent build
once they were reasonably sure Nauka was ready?

I seriously doubt that the Proton used to launch Nauka was built decades
ago.

And is this officially the last Proton to launch and no more to bve
built, replaced by Abgara, or is Angara still too immature to rule out further Protol launches?

Proton is sure to keep flying. Russia won't retire Proton until it
isn't "needed" anymore. And only Russia knows what that means.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

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On 2021-07-21 17:29, Jeff Findley wrote:

US. The Titan II missile, Titan II launch vehicle, Titan III launch
vehicle, and Titan IV launch vehicle all used hypergolic propellants in
their liquid fueled stages. But the US doesn't use them anymore.

Looking at how Soyuz had been certified for max 6 months, do the
hypergolics have a "best before" sticker on the gallons that you buy at
tye local hardware store? If you're using them for missile that remain
idle all their life, just curiious how they handle this. De-fuel
missile and put in new hypergolics every 6 months?

Hypergolic propellants are super reliable to start.

I get the advantage once you've launched, especially for little
thrusters. But have ignitions failed often at the pad? Just curious if ignition for Stage 1 have ever been an issue where hypergolics have an advantage.

Proton is sure to keep flying. Russia won't retire Proton until it
isn't "needed" anymore. And only Russia knows what that means.

What I read in Wikipedia is that it is being replaced by Angara, and not
quirte sure on status of Angara (I think they've had a test flight or
two, not sure if operational).

I Russia still tring to avoid depending on Baikonour because it is a
Russian island in Kazakhstan, or have they become mroe comfortable with it?

With Putin working to rebuild the USSR, I have to wonder if he no longer
puts strategic importance on moving stuff to Russian territory if he
expects those counries to either return to USSR or remain loyal to
Russia or face what happend to Ukraine.

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In article <hS1KI.26023$[email protected]>,
[email protected] says...

On 2021-07-21 17:29, Jeff Findley wrote:

US. The Titan II missile, Titan II launch vehicle, Titan III launch vehicle, and Titan IV launch vehicle all used hypergolic propellants in their liquid fueled stages. But the US doesn't use them anymore.

Looking at how Soyuz had been certified for max 6 months, do the
hypergolics have a "best before" sticker on the gallons that you buy at
tye local hardware store? If you're using them for missile that remain
idle all their life, just curiious how they handle this. De-fuel
missile and put in new hypergolics every 6 months?

Soyuz doesn't use hypergolic propellants. It uses nearly pure hydrogen peroxide mono-propellant. Nearly pure hydrogen peroxide will decompose
over time, which is why Soyuz is limited to about six months in space.

Hypergolic propellants are super reliable to start.

I get the advantage once you've launched, especially for little
thrusters. But have ignitions failed often at the pad? Just curious if ignition for Stage 1 have ever been an issue where hypergolics have an advantage.

For missiles, it was more about the room temperature storage (as opposed
to cryogenic LOX and kerosene used in Atlas). But, reliable ignition
after sitting in a silo for years is definitely an advantage.

Proton is sure to keep flying. Russia won't retire Proton until it
isn't "needed" anymore. And only Russia knows what that means.

What I read in Wikipedia is that it is being replaced by Angara, and not quirte sure on status of Angara (I think they've had a test flight or
two, not sure if operational).

I don't think Angara is fully operational.

I Russia still tring to avoid depending on Baikonour because it is a
Russian island in Kazakhstan, or have they become mroe comfortable with it?

With Putin working to rebuild the USSR, I have to wonder if he no longer
puts strategic importance on moving stuff to Russian territory if he
expects those counries to either return to USSR or remain loyal to
Russia or face what happend to Ukraine.

Space funding gets little love in Russia.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

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In article <[email protected]>, [email protected] says...

In article <hS1KI.26023$[email protected]>,
[email protected] says...

On 2021-07-21 17:29, Jeff Findley wrote:

US. The Titan II missile, Titan II launch vehicle, Titan III launch vehicle, and Titan IV launch vehicle all used hypergolic propellants in their liquid fueled stages. But the US doesn't use them anymore.

Looking at how Soyuz had been certified for max 6 months, do the hypergolics have a "best before" sticker on the gallons that you buy at
tye local hardware store? If you're using them for missile that remain idle all their life, just curiious how they handle this. De-fuel
missile and put in new hypergolics every 6 months?

Soyuz doesn't use hypergolic propellants. It uses nearly pure hydrogen peroxide mono-propellant. Nearly pure hydrogen peroxide will decompose
over time, which is why Soyuz is limited to about six months in space.

I should have been more clear. The six month endurance of Soyuz is
limited by the hydrogen peroxide propellant for the reaction control
system of the DM (descent module). The SM (service module) uses
hypergolic propellants.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

--- SoupGate-Win32 v1.05
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JF Mezei <[email protected]> wrote:

On 2021-07-21 17:29, Jeff Findley wrote:

Proton is sure to keep flying. Russia won't retire Proton until it
isn't "needed" anymore. And only Russia knows what that means.

What I read in Wikipedia is that it is being replaced by Angara, and not >quirte sure on status of Angara (I think they've had a test flight or
two, not sure if operational).

I think the kind term for Angara has been "development hell".

They needed 6 YEARS between "Orbital test flight No.1" (2014) and
"Orbital test flight No.2" (2020).

Supposedly they have an operational launches planned for second half
of 2021 but I'm not quite sure if that qualifies as an operational
launch - it has a payload but there's been test flights with that
before, it's unclear how important that paypload is to them.

I think it's more likely this will slide into 2022 which will make it
30 year between the development started and first operational flight.

And I'm not ruling out 2023, 2024 or even 2025, we just don't know
enough of what is going on (and what their funding situation actually
looks like).

It would have been a good rocket for them if it had operational 10
years ago, or even if the second test flight was also in 2014 but the
market has moved considerably since then.

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