Author Topic: Firefly Aerospace  (Read 10911 times)

Offline su27k

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Re: Firefly Aerospace
« Reply #40 on: 02/12/2018 04:39 AM »
I wish someone other than that Chinese firm would have the guts to just copy the Falcon 9 recovery method. These smallsat launchers, if they're flying more than a dozen times per year (let alone 24 like Firefly or 100 like RocketLab...), really ought to be at least partially reusable.

Orbit first then reuse works, there's existence proof of that. Nobody has made the reverse work yet, Blue Origin could demonstrate it but Blue is hardly your average space company.

Offline ringsider

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Re: Firefly Aerospace
« Reply #41 on: 02/12/2018 06:48 AM »
I wish someone other than that Chinese firm would have the guts to just copy the Falcon 9 recovery method. These smallsat launchers, if they're flying more than a dozen times per year (let alone 24 like Firefly or 100 like RocketLab...), really ought to be at least partially reusable.

They may not have hundreds of millions of dollars to spend on developing reuse right now.
...and that's why you essentially copy SpaceX instead of trying to do something else clever. And also: don't need that much to do what Masten and that Chinese company are doing. But I'm satisfied to know that Firefly at least paid lip service to reuse in the past.
The Spacex method won't work for small launchers if they want to stay small. The extra mass of the landing fuel, attitude system, hydraulic landing legs and titanium grid fins almost certainly makes it unworkable, because they will add much more mass than the 100-200kg  payload that these guys are trying to carry. Unless you build a much bigger vehicle for the same payload, it is unworkable - and the costs of a bigger vehicle probably make it uneconomic to build just to recover. I'm guessing, but that seems like a circular challenge.

That's why some of the images from the Spanish startup PLD Space on here a couple of days ago with grid fins and legs etc on a small launcher are more like science fiction, and that's probably why Rocket Lab isn't yet focussed on it.

Also the cost of recovery at sea in the same way as used by OCISLY in that class is probably more than the cost of building a new one, because ships, people etc have a fixed cost regardless of the size of the launcher, and become a much bigger fraction of the entire operational cost than they are of Spacex's operation.
« Last Edit: 02/12/2018 06:50 AM by ringsider »

Offline Nomic

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Re: Firefly Aerospace
« Reply #42 on: 02/12/2018 08:31 AM »
Tap off kerlox/storeable prop engines have been talked about right back to WWII, despite the claimed advantages of simplification, nobody has actually built one. On the J2S, extra hydrogen was sprayed into the tapoff ports to reduce the TIT, guess they must be doing something similar using extra RP1. Cant see a turbopump on the photo of the engine on the test stand, wonder if they are just testing the thrust chamber?

Offline chipguy

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Re: Firefly Aerospace
« Reply #43 on: 02/12/2018 05:10 PM »
On the J2S, extra hydrogen was sprayed into the tapoff ports to reduce the TIT

Temperature at Input to Turbine?

Offline e of pi

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Re: Firefly Aerospace
« Reply #44 on: 02/12/2018 05:29 PM »
Temperature at Input to Turbine?
You've got the right idea, but it's actually "Turbine Inlet Temperature".

Offline chipguy

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Re: Firefly Aerospace
« Reply #45 on: 02/12/2018 05:53 PM »
Temperature at Input to Turbine?
You've got the right idea, but it's actually "Turbine Inlet Temperature".

Thanks. I really didn't want to do an internet search.

Offline hkultala

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Re: Firefly Aerospace
« Reply #46 on: 02/13/2018 09:43 PM »
I wish someone other than that Chinese firm would have the guts to just copy the Falcon 9 recovery method. These smallsat launchers, if they're flying more than a dozen times per year (let alone 24 like Firefly or 100 like RocketLab...), really ought to be at least partially reusable.

They may not have hundreds of millions of dollars to spend on developing reuse right now.
...and that's why you essentially copy SpaceX instead of trying to do something else clever. And also: don't need that much to do what Masten and that Chinese company are doing. But I'm satisfied to know that Firefly at least paid lip service to reuse in the past.
The Spacex method won't work for small launchers if they want to stay small. The extra mass of the landing fuel
propotional to the dry mass of the vehicle
Quote
, attitude system

do you mean the cold gas thrusters?

Quote
, hydraulic landing legs and titanium grid fins

Also propotional to the dry mass of the vehicle?

Quote
almost certainly makes it unworkable, because they will add much more mass than the 100-200kg  payload that these guys are trying to carry.

Those components are first stage mass, not upper stage mass. It's not going to orbit, it does not decrease payload by the same amount.

The ratio of penalty from first stage mass to orbit is in the range of 5:1, depending on when the staging occurs.


Re: Firefly Aerospace
« Reply #47 on: 02/16/2018 03:15 PM »
So my overall assessment of this new Alpha is... different.

To be clear, thats not a bad thing. In fact, I'm quite excited to hear why they made these decisions.

The only other rocket I can think of with 4 first stage engines is the one South Korea is working on, so that alone is strange. But that number along with the different second stage engine seems especially weird today, with the market's current trend being "copy SpaceX" and use a lot of small engines on the first stage and the same engine vacuum-optimized for the second stage. Even Firefly were originally going to do this.

4 engines also ignores the more traditional approach of one big first stage engine.

Also, it seems strange to make a separate second stage engine and still use Kerolox for it.

Even the payload range is unique. They will be the first to go after the one-ton payload range.

The whole design ignores all current trends in the market, which is probably a good thing, because the SmallSat launch market is going to be quite crowded quite soon. I'm curious to see where this goes.
« Last Edit: 02/16/2018 03:17 PM by JEF_300 »

Offline Craftyatom

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Re: Firefly Aerospace
« Reply #48 on: 02/16/2018 05:41 PM »
Even the payload range is unique. They will be the first to go after the one-ton payload range.
Reminds me of that quote from a GLXP planner, about how when they started the prize, F1 and Dnepr were both flying 1/2- to 3-ton missions for cheap, but both retired before anyone got a chance to use them for anything lunar.  This would be in the same class as those two, which certainly sounds like a market with some growth potential.
All aboard the HSF hype train!  Choo Choo!

Offline TrevorMonty

Re: Firefly Aerospace
« Reply #49 on: 02/16/2018 07:10 PM »
1000kg market is perfect for smallsat LEO constellations, which is new emerging market. Those same engines can be used for follow on x9 engine RLV with payload of around 1500kg.


Offline Lars-J

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Firefly Aerospace
« Reply #50 on: 02/17/2018 12:38 AM »
1000kg market is perfect for smallsat LEO constellations, which is new emerging market. Those same engines can be used for follow on x9 engine RLV with payload of around 1500kg.

It may be perfect for smallsat LEO constellation *satellites* - but not for constellations - because I see no way that they have (or will have) enough volume capacity for the number of launches needed to launch and maintain a constellation.

The idea that any of these smallsat operators will launch 100s of times per year is fantasy. IMO.

So there may be a smallsat demand they can fill - but I think constellations are going to go elsewhere to larger operators who can handle the volume.
« Last Edit: 02/17/2018 12:57 AM by Lars-J »

Offline Robotbeat

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Re: Firefly Aerospace
« Reply #51 on: 02/17/2018 02:35 AM »
Lars-J:
Pegasus was used for launching a LEO smallsat constellation, and it has a fairing about 1m wide by 2m long. Firefly has a much larger fairing (2m and 4m, respectively, so like an order of magnitude more volume and only about twice the payload to orbit: 443kg for Pegasus XL and 1000kg for Firefly). Plenty of volume if your smallsats are designed right. The cubesat form factor, especially, is efficient for this. Planet current uses the cubesat form factor for their Doves. Cubesats have slightly greater density than water.

The fairing is 2m in diameter and has a roughly 4m usuable height. That's about 12 cubic meters, call it 10 cubic meters. At the density of cubesats, that's 10 tons (well, up to 14 tons), an order of magnitude greater payload than it actually can do. So I'd argue it's much more mass constrained than volume constrained.

I'm pretty sure Alpha could launch all of Planet Lab's cubesat constellation that is in orbit right now. And should be able to do like 5 OneWeb satellites per launch, too.


1 ton to orbit is actually a much better business proposition than the 100kg launchers, IMHO.
« Last Edit: 02/17/2018 02:36 AM by Robotbeat »
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Offline Robotbeat

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Re: Firefly Aerospace
« Reply #52 on: 02/17/2018 03:09 AM »
And Skysats (the big brother of the 3U cubesat Doves) are 60cmx60cmx80cm and weigh 83-100kg. If packed carefully, Alpha should still be mass-limited, not volume-limited. Could launch like 10 or 12 Skysats, nearly the whole constellation.

...and as someone who uses planet.com I have kind of become addicted to Skysatís much superior 0.9m resolution (just 3m for the Doves). 0.9m letís you actually see more than just blobs.
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Offline Robotbeat

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Re: Firefly Aerospace
« Reply #53 on: 02/17/2018 03:43 AM »
Just noticed, but the other image (of the whole Alpha rocket) seems to show an odd number of engines, like 5 engines:
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Lars-J

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Re: Firefly Aerospace
« Reply #54 on: 02/17/2018 04:25 AM »
Robotbeat, I was responding to a post about 1t satellites. Far different than the cubesats (and larger) you mention. And I think that we are using the word "constellation" to mean different things. No one is in the near future going to fly constellations of cubesats. No, I mean constellations of larger sats in the 0.5-1t range, and thousands of them.

Offline Robotbeat

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Re: Firefly Aerospace
« Reply #55 on: 02/17/2018 04:50 AM »
Most such constellations are dozens or hundreds. Originally, only SpaceX was crazy enough to propose a megaconstellation of thousands. And they’re much smaller than 1 ton, even for SpaceX. As I wrote, even the Oneweb satellites could be launched five at a time in the Alpha.
« Last Edit: 02/17/2018 04:51 AM by Robotbeat »
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Offline Robotbeat

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Re: Firefly Aerospace
« Reply #56 on: 02/17/2018 05:00 AM »
LarsJ: you were responding to this, which did NOT specify 1 ton satellites (you misinterpreted it) nor thousands of them.
1000kg market is perfect for smallsat LEO constellations, which is new emerging market. Those same engines can be used for follow on x9 engine RLV with payload of around 1500kg.

Most LEO constellations propose fairly small satellites such that you could launch several at once even with just the Alpha. Hereís a list (also counts MEO, which isnít relevant here):
There was a wave of FCC filings November 15.

Audacy: 3 MEO relays to communicate with LEO spacecraft.
SATLOA2016111500117

Karousel: 12 IGSO satelllites for video
SATLOA2016111500113

Kepler MULTUS: 2-140 LEO nanosats for M2M communication
SATLOI2016111500114

LeoSat: 78 LEO satellites
SATLOI2016111500112

O3b: Amendment to add another 40 satellites
SATAMD2016111500116

SpaceX: has its own thread
http://forum.nasaspaceflight.com/index.php?topic=41634.0
SATLOA2016111500118

Space Norway: 2 satellites in high-inclination 16-hour orbit
SATLOI2016111500111

Telesat Canada: 117 in LEO
SATLOI2016111500108

Boeing: 60 IGSO (this is separate from the smallsat filing they also have)
SATLOA2016111500109

Theia: 112 for remote sensing
SATLOA2016111500121

Viasat: 24 in polar MEO
SATLOI2016111500120
« Last Edit: 02/17/2018 05:01 AM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline TrevorMonty

Re: Firefly Aerospace
« Reply #57 on: 02/17/2018 01:27 PM »
For likes of SpaceX 4000 smallsats, large LV like F9 is only way to go for initial placement. Small LVs are better for urgent service replacements in these cases.

As Robot pointed out there are lots little constellations containing anyway from 2-50 smallsats in 100kg range that need deployment to specific orbits. These prefer LVs in 200-1000kg range.

Alpha will compete directly with PSLV, Vega and LauncherOne for smallsats. Electron is slight different market, 1-3 smallsats and cubesat deployment.

With addition of 3rd stage Apha could open up dedicated launch to BLEO for smallsats. 

Re: Firefly Aerospace
« Reply #58 on: 02/21/2018 04:40 PM »
Just noticed, but the other image (of the whole Alpha rocket) seems to show an odd number of engines, like 5 engines:

It's just viewing the four engines from a corner instead of a side

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