Author Topic: Astra Space  (Read 419635 times)

Offline Ben

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Re: Astra Space
« Reply #280 on: 02/25/2020 10:52 pm »
(1:5 would be a particularly large 2nd to 1st stage thrust ratio so it should be much smaller.)

Even 1:9 like Falcon 9 and Rocketlab makes for a large upper stage, when looked at as a split of delta-v. Having a big upper stage makes sense if you're trying to recover the first stage because that means it stages much lower and slower, but all the talk I've seen of Astra is "inexpensive expendable" rather than "high performance reusable".

Offline illectro

Re: Astra Space
« Reply #281 on: 02/25/2020 10:58 pm »
If you look at the video where they are attaching the payload, you can see that the second stage extends up inside the fairing, so the second stage is longer than the frustrum section alone. The angles make it hard to see how much longer, and how wide it is.

Offline Comga

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Re: Astra Space
« Reply #282 on: 02/25/2020 11:13 pm »
All conventional wisdom suggests the upper stage is located in the white-painted cone structure before the payload fairing. But to fit in there along with the avionics bay, it must be very small.

Agreed. Why is it white, ya think?

Do you think there is a dramatic difference in solar irradiance rejection between white paint and bare aluminum?  There is not.

There is a dramatic difference in long wave infrared emissivity and absorptivity but that doesnít have much effect if itís cooled to the boiling point of LOX.

If you have an engineering reason for the white paint or whatever it is please spell it out.

ya think ya could? :)
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline HeartofGold2030

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Re: Astra Space
« Reply #283 on: 02/25/2020 11:20 pm »
So are we thinking that the upper-stage is a Delta-K kind of deal?

Offline Ben

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Re: Astra Space
« Reply #284 on: 02/25/2020 11:28 pm »
For the same reason basically every other rocket is white. Here's a hint: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710004639.pdf

I have slow motion video somewhere of getting shocked hard and jumping when grabbing a rocket that was doing hover testing with a nonconductive tether. I added a ground wire to the tether after that.

Offline illectro

Re: Astra Space
« Reply #285 on: 02/25/2020 11:31 pm »
Note on this screengrab from the factory that we have a series of bulkheads on the left, there are two sizes. I'm guessing the smaller ones are from the second stage.

Offline ParabolicSnark

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Re: Astra Space
« Reply #286 on: 02/25/2020 11:31 pm »
I have word that the second stage is almost entirely in the interstage. Now whether it's like the Delta-K setup like HaertofGold2030 posted or more like LauncherOne's fuel tank, I can't say - I didn't poke or prod about it at the time.

The white paint is curious, because in either of those cases, the tank walls are shielded from the environment by the interstage walls. That indicates it's likely not thermal driven and could be electrical like Ben suggested.

Offline QuantumG

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Re: Astra Space
« Reply #287 on: 02/26/2020 02:32 am »
For the same reason basically every other rocket is white. Here's a hint: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710004639.pdf

I have slow motion video somewhere of getting shocked hard and jumping when grabbing a rocket that was doing hover testing with a nonconductive tether. I added a ground wire to the tether after that.

Thanks for informing us. Can you comment any more on the second stage? Is it, as many have speculated, a vacuum optimized version of the first stage? Or something completely different?
Human spaceflight is basically just LARPing now.

Offline edkyle99

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Re: Astra Space
« Reply #288 on: 02/26/2020 01:49 pm »
It has been a long time, since the early Cold War days, since a new orbital launch vehicle has reached the pad with such minimal technical information released.  Liftoff thrust?  Weight of rocket at launch?  Ascent timelines, etc.?  The second stage propellant.  Bizzarosecret.

Keep in mind, too, that Electron is really a three-stage rocket, the third stage being secret until it flew successfully.  Any number of surprises could be inside that Astra rocket fairing.

 - Ed Kyle
« Last Edit: 02/26/2020 01:54 pm by edkyle99 »

Offline Ben

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Re: Astra Space
« Reply #289 on: 02/26/2020 02:44 pm »
Launch mission control is in California. Have there been launches with mission control that far from the rocket? I know SpaceX has the pretty mission control in California on webcasts, but I believe the launch is run from the smaller facility at the south gate of CCAFS.

https://twitter.com/uanwer/status/1231319518128984067

Offline edzieba

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Re: Astra Space
« Reply #290 on: 02/26/2020 02:50 pm »
It's also the closest thing to a containerised road-transportable ICBM + TEL system that can launch from a minimally-prepared site, that is not also a missile-derived launcher. I could easily see ITAR concerns being heightened vs. something that requires a large fixed ground infrastructure.

Offline Ben

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Re: Astra Space
« Reply #291 on: 02/26/2020 03:09 pm »
It's also the closest thing to a containerised road-transportable ICBM + TEL system that can launch from a minimally-prepared site, that is not also a missile-derived launcher. I could easily see ITAR concerns being heightened vs. something that requires a large fixed ground infrastructure.
I think you are confusing ITAR with a more generalized proliferation concern. There is no special ITAR concern to building a portable launch system unless it is Internationally Trafficked. This seems to be a boogeyman people are making up, similarly to how a lot of people seem to think that putting guidance on an amateur rocket is somehow illegal.

ITAR is much more relevant if you were a launch company that split their engineering between the US and New Zealand. Or a launch company bought by a Ukranian who offshored IP to Ukraine. Or were a US launch company owned by a British billionaire. Or were a British firm designing engines in the UK but testing them in the US and exporting test results.

Offline russianhalo117

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Re: Astra Space
« Reply #292 on: 02/26/2020 03:09 pm »
It's also the closest thing to a containerised road-transportable ICBM + TEL system that can launch from a minimally-prepared site, that is not also a missile-derived launcher. I could easily see ITAR concerns being heightened vs. something that requires a large fixed ground infrastructure.
It is designed for all methods of shipment. The containers have an owner ID number on them for international shipment. If someone were to identify them then they can be tracked via shipping databases (although National Security concerns may prohibit such actions).

Offline edzieba

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Re: Astra Space
« Reply #293 on: 02/26/2020 04:19 pm »
The concern is not in the shipment or the building, is in the dissemination of information on how it was done. That's what ITAR covers.

Offline Bananas_on_Mars

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Re: Astra Space
« Reply #294 on: 02/26/2020 05:51 pm »
Launch mission control is in California. Have there been launches with mission control that far from the rocket? I know SpaceX has the pretty mission control in California on webcasts, but I believe the launch is run from the smaller facility at the south gate of CCAFS.

IIRC weĎve seen remotely (as in from headquarters) controlled engine tests from Vector and Firefly, but of course no launch from them. At that time i didnít realize why it could make sense running those tests from afar if you need people in situ for setting up the test. But it demonstrates a lot of the stuff necessary for remote launch control.

Offline Bananas_on_Mars

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Re: Astra Space
« Reply #295 on: 02/26/2020 06:09 pm »
Keep in mind, too, that Electron is really a three-stage rocket, the third stage being secret until it flew successfully.  Any number of surprises could be inside that Astra rocket fairing.

 - Ed Kyle

If they want to do more than one burn with it, their second stage will need some RCS etc. With the stage inside the interstage/fairing, all that stuff is inside a controlled environment, and doesn’t need ports on the outside that have to be protected etc.

The second stage can be a lot? lighter if it doesn’t have structural loads from the fairing, like the centaur upper stage on the bigger fairings on Atlas.

Having a shorter burn on the upper stage (via longer burn on first stage) also might make the battery swap that Rocketlab does unnecessary.

Offline edkyle99

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Re: Astra Space
« Reply #296 on: 02/27/2020 02:57 am »
Having a shorter burn on the upper stage (via longer burn on first stage) also might make the battery swap that Rocketlab does unnecessary.
I'm not sure we know that the second stage engine has a battery powered pump, or even that it has any pump.  It could be pressure-fed, or maybe even use solid propellant.  This is a tiny rocket.  Not much leeway for fancy stuff.

 - Ed Kyle

AE/ME
6 Suborbital spaceflight payloads. 14.55 minutes of in-space time.

Offline edkyle99

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Re: Astra Space
« Reply #298 on: 02/28/2020 03:23 am »
I see Scott Manley reported Astra first stage thrust at 140 kN (about 31,470 lbf), or 28 kN for each of the five Delphin engines.  Interestingly, that's about the same ballpark as the Vanguard first stage.  Its roughly 91% of the Electron first stage thrust.  GLOW would be about 11 tonnes if T/W = 1.3, 10.2 tonnes for T/W = 1.4, etc.  (Vanguard weighed 10.05 tonnes.  Electron 12.55 tonnes.)

 - Ed Kyle
« Last Edit: 02/28/2020 03:31 am by edkyle99 »

Offline Ben

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Re: Astra Space
« Reply #299 on: 02/28/2020 06:22 am »
Hopefully enough to improve the model of the fairing.

Most or all shot by John Kraus.
« Last Edit: 02/28/2020 06:32 am by Ben »

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