SpaceX looks at Saturn V class

[savuporo]

bytheway, reading the archives, about 5 years ago Orbital was involved in developing liquid fuel boosters for MDA target practice.
has anything space-related come out of it ?

[Analyst]

bad_astra - 25/4/2007  3:45 AM

When they orbit something, which might be next time, they'll be in the same league as Orbital. I think there'll be room enough for both.

When and only when they do it and can repeat it successfully at least once, better four or five times, they'll be in the same league as Orbital. When they do it with different vehicles, from different launch sites for many paying customers over a decade, they' be even with Orbital. Miles to go!

Analyst

[Avron]

Analyst - 25/4/2007  7:37 AM

bad_astra - 25/4/2007  3:45 AM

When they orbit something, which might be next time, they'll be in the same league as Orbital. I think there'll be room enough for both.

When and only when they do it and can repeat it successfully at least once, better four or five times, they'll be in the same league as Orbital. When they do it with different vehicles, from different launch sites for many paying customers over a decade, they' be even with Orbital. Miles to go!

Analyst

Sounds like a no win position... or would Mass to LEO count?

aero313 - 24/4/2007  4:14 PM By the way, when Pegasus was developed, Hercules and Orbital formed a joint venture, so the rocket motors weren't "subcontracted", they were developed by the JV.

BTW, OSC is an example of financial best practices in use of capital with Pegasus, as opposed to Kistler - so the use of strategic resources can allow for bringing off a very effective project. Pegasus/Taurus also wins by being a very specific end design(s) in itself. Biggest criticism of this business is the market size it claims to address - too small. But smartly used strategic resources caps your downside here too - low ongoing costs or commitment to further development.

The same isn't true for Falcon 1. Falcon 1 isn't an end-design, but the beginning of a progression. They are not comparable at this point, as the development of Falcon 9 addresses a quite larger market than OSC's product line encompasses. Comparing OSC and Space-X is even harder. At first blush, they are more compatible as potential partners than eyeball-to-eyeball competitors.

[Paul Howard]

Flight global have been pimping SpaceX for some time now. If someone at SpaceX told them that Elon had worked out a light speed engine, they'd write it.

[Avron]

Paul Howard - 25/4/2007  8:22 PM

Flight global have been pimping SpaceX for some time now. If someone at SpaceX told them that Elon had worked out a light speed engine, they'd write it.

They need to build the modern F-1 first.. then give them 6 months...

[coach]

Pure speculation here but what kind of configuration will this BFR have?  Can they scale up the old Falcon 5 design with 2 five engine boosters?  That makes for more liftoff thrust than the Saturn 5 if the new Merlin 3 has roughly 1/2 the thrust of the F1.  Will they design their own LH2 upper stage?  Will the drop off boosters be better perfomance overall than the 3 pure stages of the Saturn?  This seems to be the direction that SpaceX is headed even if they don't make it quite this large.  They like the liquid strap ons despite the limited success in the past from others who have tried.  What a sight at liftoff, huh?  Fifteen engines putting out more than 10 million pounds of thrust.  Yikes!


Coach

[khallow]

It looks straightforward to me. It'd be a poor idea to keep adding more Merlin engines past 9. Doesn't scale. My take is that they develope this new engine and replace the 9 Merlins with one of these engines on the Falcon 9. If the space economy picks up to the point where a Saturn V class rocket makes sense, then they'll be well positioned. But they don't need an HLV to use the new engine.

Even if the engine turns out to be uneconomical for a decade or two, it still seems a reasonable use of the existing design team. They have a slim chance of sneaking ahead of the current big players which could look good to potential investors. And of course, "looking" and talking about looking is cheap.

meiza, in reference to your early comment, SpaceX has also developed the Kestrel which is a 31kN  thrust rocket used on their upper stage of the Falcon I. Still not much development experience, but two is more than one.

[SolarPowered]

SolarPowered - 17/4/2007  2:18 PM

Elon has said that this engine will be the biggest engine around with a single combustion chamber.  So, it is presumably bigger than an RS-68 and smaller than an RD-180.  Or, around half of the old F-1.

When I posted my comment that I just quoted, I was passing on the interpretation of the article in which I read about Elon's comment.  It has since occurred to me that there are, of course, bigger multiple-chamber engines than the RD-180; specifically, the RD-171 is in the 1.7 million-pound-thrust range.

So I'll correct my interpretation of his remark, and speculate that he was talking about something bigger than an RDS-68, and smaller than an RD-171.

[josh_simonson]

Or perhaps between RS-68 and F-1, otherwise he'd say 'the largest single combustion chamber engine ever' rather than 'around'.  RD-171 outpushes F-1 by about 15%.

[SolarPowered]

The edit button seems to have gone away for some reason.  I meant, of course, "RS-68", not "RDS-68".

[simonbp]

josh_simonson - 25/5/2007  8:19 PM

Or perhaps between RS-68 and F-1, otherwise he'd say 'the largest single combustion chamber engine ever' rather than 'around'.  RD-171 outpushes F-1 by about 15%.

And a Shuttle RSRM outpushes an F-1 by 87%, but don't tell anyone, because admitting that solids might be useful is heresy around here...

Simon

[jongoff]

Simon,

And a Shuttle RSRM outpushes an F-1 by 87%, but don't tell anyone, because admitting that solids might be useful is heresy around here...

It's not so much that solids are never useful, it's just that we think that ATK/NASA are overhyping how safe and useful they are.  Thrust isn't everything.

~Jon

[simonbp]

jongoff - 28/5/2007  7:16 PM

Thrust isn't everything.

And neither is Isp; one must balance the both, as Ares does with a high-thrust first stage and a high-energy upper stage.

And, strictly speaking, the Shuttle's SRB does have 200+ flights with one failure that has since been rendered impossible. By anyone's measure, that's a pretty stellar flight record...

Simon

[jongoff]

Simon,

And neither is Isp; one must balance the both, as Ares does with a high-thrust first stage and a high-energy upper stage.

I agree that Isp isn't everything.  A lot depends on the application.  The problem is that the first stage in this case provides so little of the overall delta-V that the upper stage ends up being an almost SSTO stage.  While there are some situations where that is ok (like for some reusable designs where it allows you to return the first stage to the launch site, or to use a very low cost first stage), I think that in this case it's far from optimal.  More importantly, I don't think there's a single benefit to Ares-I's approach that comes close to justifying the extra $10B to develop it and field it instead of adapting to existing launch vehicles.

And, strictly speaking, the Shuttle's SRB does have 200+ flights with one failure that has since been rendered impossible. By anyone's measure, that's a pretty stellar flight record...

AIUI, the strapon boosters for Soyuz have done fairly well too.  I remembered this coming up in discussion either here or on another list, but every Soyuz flight uses 4 of these strapons.  I think the total number of flights of Soyuz strapon stages is close to 4000-5000 with less than 20 failures.  

I don't have precise numbers, but at least on their face they appear fairly comparable to the reliability of shuttle SRBs.  

More to the point, Ares I and Ares V don't use Shuttle SRBs, they use what amounts to an entirely new stage with very little hardware that is exactly identical between the two.  It could be that this will end up being just as reliable, but...that's an assumption not a proven fact.

Personally, I doubt that Ares I will fly even 100 times before it is either canceled or has managed to kill a crew.

~Jon

[joh]

More to the point, Ares I and Ares V don't use Shuttle SRBs, they use what amounts to an entirely new stage with very little hardware that is exactly identical between the two. It could be that this will end up being just as reliable, but...that's an assumption not a proven fact.

The new SRBs will be stacked using the existing RSRM Segments. And i bet, they use the same aft segmets including TVC as they do today. What changes is the number of segments from 4 to 5, a slightly different filling and adding a RCS system in the interstage providing roll control for Ares-I.

[pippin]

Does SpceX build Ares' now? :confused:

[JIS]

joh - 29/5/2007  1:45 PM

More to the point, Ares I and Ares V don't use Shuttle SRBs, they use what amounts to an entirely new stage with very little hardware that is exactly identical between the two. It could be that this will end up being just as reliable, but...that's an assumption not a proven fact.

The new SRBs will be stacked using the existing RSRM Segments. And i bet, they use the same aft segmets including TVC as they do today. What changes is the number of segments from 4 to 5, a slightly different filling and adding a RCS system in the interstage providing roll control for Ares-I.

Spare your arguments. It's about belief.

[aero313]

joh - 29/5/2007  8:45 AM

More to the point, Ares I and Ares V don't use Shuttle SRBs, they use what amounts to an entirely new stage with very little hardware that is exactly identical between the two. It could be that this will end up being just as reliable, but...that's an assumption not a proven fact.

The new SRBs will be stacked using the existing RSRM Segments. And i bet, they use the same aft segmets including TVC as they do today. What changes is the number of segments from 4 to 5, a slightly different filling and adding a RCS system in the interstage providing roll control for Ares-I.

Anyone who thinks creating the five segment booster is really this simple is naive at best.  This is a brand new SRM.  The case segments may be common (well, except for that forward part that has to interface to a new upper stage), but the grain configuration is brand new, the casting tooling will be new, the thrust curve will be new, the insulation will be different, the throat will be new, etc.  And this is just the rocket motor.  There's just as much work necessary on other subsystems and components to turn it into a stage.

[GraphGuy]

IF spaceX wants to create an F1 class engine, more power to them and have fun with it.  Also not to diminish the effort that goes into creating an engine of that size/power, but they aren't creating the wheel for the first time and I suspect that it would take quite a bit less money and manpower than in the 60s.

I like rooting for spaceX.  Hopefully they actually put something into orbit soon.  At the very least they have some neat webcasts ;-)

Ultimately I think that having a single F1 engine would be better than 9 of their current engines, assuming that they can book enough launches to keep the production line going.