Space Ship Two - General Thread

[parabolicarc]

Rutan also was a novice at rocketry, thought liquid rockets were too complicated, and had no understanding of how dangerous nitrous oxide is when its in a big tank under pressure. Also, there's a story in Rocketeers about a liquid rocket company coming in and mistakenly showing Rutan a video of one of their rockets exploding on the test stand.

I believe the plan to replace the engine casing and rocket nozzle as a unit after each flight. They're a single unit from what I've seen here in Mojave. I would think the casing could be refilled and reused with the nozzle, but I'm not entirely sure.

[bad_astra]

I think Rutan believed that hybrids were safer. If they had chosen the liquid rocket route, they were not necessarily going to be forced to bankrupt themselves having Thiokol restart XLR99 production, or anything like that.

 There were manufacturers who could have build an engine for them, XCOR, Armadillo, Microcosm, but they had made their decision. The vehicle is constrained by the space given and dimensions of the hybrid motor. In my opinion it looks more and more like a developmental dead end.

"I absolutely have to develop a manned space tourism system for Sir Richard Branson that's at least a hyundred times safer than anything that's ever flown man into space and probably a lot more. I have to do that. What you see here is a research and dev program to look at new ideas on how manned spacecraft can really be significantly safer. And that was with this new type of hybrid motor, which is significantly safer" -Burt Rutan.

When you make a statement like that and hang it on the nail of one class of engine, it is hard to pull it down.

[Patchouli]

I never understood why they chose those hybrid engines. Kerosene engines seem to be much more useful.

If you were designing it now, I would agree, but it makes more sense in the context of when the decision was originally made. When SS1 was being designed, sufficiently high performance liquid engines were pretty much the domain of Big Aerospace. Developing one would be expected to be expensive and technically risky. Hybrids were supposed to be the cheap and simple alternative. When it came time to do SS2, a "simple" development from SS1 was still a logical choice, even if the engine choice was starting to looks sub-optimal.

Fast forward to today, hybrids turned out to be not so simple and other groups showed that it was possible to develop LOX/hydrocarbon engines on a relatively small budget.

At the time the decision was made a liquid engine of sufficient performance meant dealing with the complexity and cost of a turbo pump.

Xcor pretty much turned the entire notion of a high performance liquid engine being expensive on it's head with their novel piston pump design.

Then there was the belief of handling cryogenic propellants was inherently difficult and dangerous.

Remember the X33 had just been canceled due to it's composite lH2 tanks failing and it probably put a lot of people off on cryogenic composite tanks in general.

N2O is a liquid at room temp and reasonable pressures.

[meekGee]

At the time the decision was made a liquid engine of sufficient performance meant dealing with the complexity and cost of a turbo pump.

Xcor pretty much turned the entire notion of a high performance liquid engine being expensive on it's head with their novel piston pump design.

Then there was the belief of handling cryogenic propellants was inherently difficult and dangerous.

Remember the X33 had just been canceled due to it's composite lH2 tanks failing and it probably put a lot of people off on cryogenic composite tanks in general.

N2O is a liquid at room temp and reasonable pressures.

At the time the decision was made, XCOR was just around the corner.

If Jeff Greason had the fund-raising ability of people like Branson or Peter Diamandis, there'd be a Lynx v 3.0 by now.

I was at the XCOR Hanger right after SS1 first flew.  Jeff was explaining how the piston pump and a runway-takeoff concept would make for a lower price point, when flyboy Rutan comes marching into Jeff's hangar, all leather clad and followed by a bone-fide entourage.  All the press turns around, forgets Jeff, and awaits for a quote from Rutan, who does not disappoint:  "I found a way to make the engine cost zero" he says.  "We're going to cut up the nozzle into 6 pieces and sell them to the passengers as souvenirs!".

Yuh.

Long story short, Jeff never even got to finish his explanation of Lynx. I mean what does he know, he only builds rocket engines.

[QuantumG]

If Jeff Greason had the fund-raising ability of people like Branson or Peter Diamandis, there'd be a Lynx v 3.0 by now.

I think you're confusing cause and effect here. There will be a Lynx someday which actually does what Greason says it'll do, because he's not a Branson or a Diamandis.

[meekGee]

If Jeff Greason had the fund-raising ability of people like Branson or Peter Diamandis, there'd be a Lynx v 3.0 by now.

I think you're confusing cause and effect here. There will be a Lynx someday which actually does what Greason says it'll do, because he's not a Branson or a Diamandis.

 

But if he had funding, he'd have been able to move faster.

There are a few examples of kick-ass engineers who also understand a thing or two about running businesses and raising funds, but the honesty and objectivity that is really required for being an engineer does kind of get in the way when you try to convince the good people of NM to give you all that money so you can have a playground...


Which reminds me:  "What's the difference between an introvert engineer and an extrovert engineer?"

[parabolicarc]

Interview with Whitesides from Aabar Investments website:

http://www.parabolicarc.com/2014/04/20/whitesides-spaceflight-schedule-year/

And Whitesides promises to be a on test flight:

http://www.parabolicarc.com/2014/04/20/whitesides-vows-fly-spaceshiptwo-test-flight/

[Blackstar]

A pretty devastating article and some impressive reporting work:

http://www.parabolicarc.com/2014/04/22/space-conferences-engine-claims-silly-putty/

Space Conferences, Engine Claims and Silly Putty
Doug Messier
on April 22, 2014, at 3:32 pm


"The agreement, which was signed at the Oshkosh airshow five years ago this July, expires at the end of 2014. Multiple, reliable sources says there is a provision that requires Virgin Galactic to fly Branson into space by the end of the year.

If the company fails to reach that milestone, there are significant claw backs in the agreement.  It’s not clear precisely what the claw backs are, but it could involve repayment of some of the original $390 million investment or an increase in aabar’s 37.8 percent share of the company."

[Lars_J]

Wow, that is certainly eye-opening and devastating - if true. But Doug seems to be well-informed.

[parabolicarc]

WhiteKnightTwo has cracks in its wings:

http://www.thesundaytimes.co.uk/sto/news/uk_news/People/article1409455.ece

Or, as Virgin Galactic claims, adhesive imperfections.

My sources say cracks. Nobody I've talked with has referred to them as adhesive imperfections.

[QuantumG]

Not just WK2.

[Kabloona]

WhiteKnightTwo has cracks in its wings:

http://www.thesundaytimes.co.uk/sto/news/uk_news/People/article1409455.ece

Or, as Virgin Galactic claims, adhesive imperfections.

My sources say cracks. Nobody I've talked with has referred to them as adhesive imperfections.

For those who can't get past the Sunday Times paywall:

http://www.parabolicarc.com/2014/05/11/london-sunday-times-story-cracks-whiteknighttwos-wings/

[Ric Capucho]

Not just WK2.

Just reread this post and spotted the hint. Can you expand on this a little bit?

Ric

[QuantumG]

Not just WK2.

Just reread this post and spotted the hint. Can you expand on this a little bit?

We're on page 92.

[Ric Capucho]

Not just WK2.

Just reread this post and spotted the hint. Can you expand on this a little bit?

We're on page 92.

Indeed we are. Consider myself chastened. Consider myself unsure why. Can anyone else help?

Ric

[Olaf]

https://www.facebook.com/?sk=welcome#!/virgingalactic?fref=nf

Great day to be back on the runway with WhiteKnightTwo! Today, we were taxi-testing new landing gear that is rated for commercial service.

[QuantumG]

Indeed we are. Consider myself chastened. Consider myself unsure why.

Fair enough.. my point was, it's a long thread, the story has been building for years.

I asked Mark Sirangelo similar questions on The Space Show. http://www.thespaceshow.com/guest.asp?q=977

He shut me down pretty quickly with a simple answer that I didn't expect: Sierra Nevada considers this motor to be "mature" already. There's not in a "test program" on this motor at all.

simply making one final attempt to optimize the motor

It seems that is the way they see it.. they're merely improving on a mature design.

I have been hearing doubts about the motor's performance from some industry professionals

I have been hearing that for years.. none of these industry professionals mentioned the heritage of the rocket, they all seemed to think it was developed for SS1. I've yet to get a straight answer as to Tim Pickens' involvement.. some say he developed the rocket for SS1 from scratch, and that the SS2 rocket is a continuation of that work.. others say there's no relationship between these rockets.

Trent, are you talking about SS2 or DreamChaser? I thought you were highly critical of SC's decision to go with hybrids (rather than buying engines from XCOR) and highly skeptical about progress on RM2.

Oh, I was.. and SNC's official comment for 3 years was "no comment".. suddenly, in the last 12 months, they started actually answering questions and became clear that they've been covering for Scaled.

Hybrids vs liquids is a completely different question and yeah, I still think XCOR will win in the long run.

Very interesting. Any ideas on what the real culprit is?

6 years to first flight. But let's ignore that.

My speculation is that all this rocket motor testing, which SNC insists are being demanded by Scaled Composites, are not about maturing a rocket.. they're trying to solve a structural issue with SS2.

Quantum, if there's no problem with RM2, then why will they be using a "battleship" "baby" motor for the first powered flights?

I don't know.. but why do you think? Can you maybe guess?

SNC says there's nothing wrong with their motor and that they're sick of SC saying that there is (yes, they actually said that.. it was "off the record" but multiple people reported the same exasperation). So, if there's nothing wrong with the motor, then maybe there's something wrong with... can you guess?

Why is it taking so long?

It's never been done before, so every crack (*cough*) is filled with peril.

I'm sure I made some more cracks about it too, but searching NSF is like pulling teeth.

[Ric Capucho]

Ok, so a play on words with regards to "cracks" which I took literally. SS2 *doesn't* have spar cracks to add to its woes.

Understood.

White Knight is an amazing bit of technology in its own right, able to carry a sizable external payload to dizzy heights hitherto accessible only to the likes of the Avro Vulcan, Concorde, U2 and a few select others. To mix the shenanigans of SS2 and its design flaws (IMHO) seems unfair.

WK2 has developed cracks in its spars and VG is spinning... ok, got that. But clever people will fix that. In time. WK2 ain't a lemon.

Meanwhile, the *real* gorilla in the room is SS2 and its troubled propulsion concept. And yes, SS2 is years overdue and... ahh, words fail me.

 Ric

[R7]

Even greater gorilla is Model 351. Let's hope its wing spar will be as good as it is cracked up to be. Could be leased to haul several SS2s at once.

[savuporo]

Whitesides all but confirms that the ship wont get to 100km, at least not initially.
And that they have snuck in a 50-mile altitude, not the Karman line 62 mile/100km altitude into customer agreements since beginning. No word on if their agreements also discuss the minimum number of passengers in cabin - or how tall and heavy you can be before the flight.