Space Ship Two - General Thread

[Lurker Steve]

So are they just straight up lying in their press release from several days ago then?  It stated " the [engine] system has been successfully tested in ground firings to demonstrate performance characteristics and burn time sufficient to take the spaceship and its private astronauts to space"

http://www.virgingalactic.com/news/item/virgin-galactic-reaches-new-heights-in-third-supersonic-test-flight/

The careful wording by VG concerning engine performance certainly adds to the perception that something is amiss.

I didn't really see anything in the press release about questionable engine performance. I didn't realize that the extra thermal protection was to protect the tail fins from heat from the rocket engine. Is that tail heating one of the factors limiting the amount of burn time for the hybrid motor ? I would certainly like to see a 30 second burn on the next flight.

[Patchouli]

VG probably have to rebuild the SS2 after each hybrid engine burn. They need a propulsion system that can be reuse or quickly re-furbished.
 
The current powered flights are just to test fly back characteristics and SS2 deployment from WK2 IMO.

They probably designed it such that solid part of the hybrid motor comes out with a few bolts and they just replace everything behind the injector head as a unit.

[Danderman]

VG probably have to rebuild the SS2 after each hybrid engine burn. They need a propulsion system that can be reuse or quickly re-furbished.
 

I have seen no information that supports the above statement. VG has been pretty clear that the intent was to be able to quickly swap out the hybrid motors, and this procedure was accomplished a few times with SS1.

[parabolicarc]

So ... nothing much has changed in the past 4 weeks, then.  That shouldn't be surprising.

That's an accurate assessment. There's more, but nothing I can say at this time.

There was a test of the nylon-nitrous engine in Mojave this afternoon.

http://www.parabolicarc.com/2014/01/16/exclusive-pictures-spaceshiptwo-engine-test-firing-mojave/

http://www.parabolicarc.com/2014/01/16/spaceshiptwo-engine-test-mojave-today/

[yg1968]

So ... nothing much has changed in the past 4 weeks, then.  That shouldn't be surprising.

That's an accurate assessment. There's more, but nothing I can say at this time.

There was a test of the nylon-nitrous engine in Mojave this afternoon.

http://www.parabolicarc.com/2014/01/16/exclusive-pictures-spaceshiptwo-engine-test-firing-mojave/

http://www.parabolicarc.com/2014/01/16/spaceshiptwo-engine-test-mojave-today/

How soon can this new engine be used in a (short duration) test flight?

[yg1968]

Will Pomerantz, VP for special projects at @virgingalactic says the company will share some technology developments "soon." #aiaaSciTech

https://twitter.com/Leone_SN/status/423115155283509248

[parabolicarc]

WhiteKnightTwo and SpaceShipTwo are on the ramp this morning in Mojave. Looks like there's going to be a glide flight because SpaceShipTwo is not fitted with an engine.

I'm in Mojave now. I'll be posting updates at http://www.twitter.com/spacecom and http://www.parabolicarc.com

[Skyrocket]

VG posted on Facebook, that SpaceShipTwo has performed a successful glide flight (unpowered). Crew was this time Siebold and  Sturckow.

[parabolicarc]

So ... nothing much has changed in the past 4 weeks, then.  That shouldn't be surprising.

That's an accurate assessment. There's more, but nothing I can say at this time.

There was a test of the nylon-nitrous engine in Mojave this afternoon.

http://www.parabolicarc.com/2014/01/16/exclusive-pictures-spaceshiptwo-engine-test-firing-mojave/

http://www.parabolicarc.com/2014/01/16/spaceshiptwo-engine-test-mojave-today/

How soon can this new engine be used in a (short duration) test flight?

Unknown at this time when or if it will be used in a test flight. They're crunching the numbers and evaluating the performance now.

[parabolicarc]

VG posted on Facebook, that SpaceShipTwo has performed a successful glide flight (unpowered). Crew was this time Siebold and  Sturckow.

The flight looked good, from what I could see of it. I was down at the airport for the landing. Even up at the drop zone it's tough to see very much of the drop and early flight since they are so high (about 46,000 feet).  It was CJ Sturckow's first SS2 flight. He's with Virgin Galactic, so I'm guessing this was a check-out flight that is in preparation for the expected handover of operations from Scaled Composites to Virgin Galactic later this year. Pete Siebold from Scaled was also in the SS2 cockpit.

[Borklund]

FWIW I can offer a second hand account of what customers are being told. I recently had the opportunity to meet Swedish adventurer and Virgin Galactic customer Renata Chlumska. She is #192 in the queue to go to space and VG are telling customers they're still on for commercial operations to start in 2014 with six minutes time in zero G. No pressurised suits, just a coverall/uniform type thing; getting in and out of seats shouldn't take up significant time.

[Jarnis]

Really? A flight to that altitude with no apparent plan B if the cabin is depressurized?

I didn't expect full blown pressure suits, but I did expect at least oxygen masks and partial pressure ("get-me-down") suits of some sort for emergencies. Flights at those altitudes are no picnic. Heck, even Concorde max altitude was limited by the emergency procedures - how fast they could get to a safe altitude from whatever altitude they were flying at in case a window blew out or something.

Then again, I guess cabin depressurization has been exceedingly rare, so this being a short hop, it might be what they plan on doing, risks and all. I just would think that cabin depress at late stages of the rocket burn or right at around nominal cutoff would be a Very Bad Day as the lob takes 6 minutes, plus whatever it takes to dive from beginning of re-entry to a safe altitude (10 000 feet?)

Sure, those who are flying are free to do it with whatever level of risk they like. I'm sure the waiver will be a thick pile of paper that basically says "it's a suicide run, if you come down alive it, be grateful. Either way, you can't sue us".  - just wondering what the reasoning behind this is and if FAA truly is okay with it.

[Avron]

Sure, those who are flying are free to do it with whatever level of risk they like. I'm sure the waiver will be a thick pile of paper that basically says "it's a suicide run, if you come down alive it, be grateful. Either way, you can't sue us".  - just wondering what the reasoning behind this is and if FAA truly is okay with it.

FAA's primary responsibility in these flights is to minimize the  risk to the public who are not directly involved. Those  in evolved need  only sign a waiver. Its like any other experimental aircraft. The launch and landing licence basically shows that the necessary due diligence has been taken to show that there a proven statistically very small risk to the general public, and all safeguards are in place to ensure that  risk level is maintained.

[woods170]

Really? A flight to that altitude with no apparent plan B if the cabin is depressurized?

When the shuttle was on-orbit and the cabin would rapidly depressurize after the ACES suits had been stowed, there was no plan B either. Not that shuttle carried passengers/tourists...
Same for Soyuz when it still used the two-day approach to ISS. A few hours after launch crew would doff the ascent/entry suits. If the cabin would rapidly depressurize after that; no plan B because it would take far too long for the cosmonauts to get suited up again.
Just sayin' that going into space with no (or barely no) provisions against rapid cabin depressurization is not exactly new. It's been done for over 4 decades.

[Jarnis]

Sure, but doesn't just about every manned ship have provisions for that during ascent (which is when the pressure changes and the fact that the hull holds pressure is ultimately tested)?

I guess it still falls into the "perfectly acceptable risk" and to be honest, if I were to get on that contraption, I would be far more worried about the whole rocket engine than cabin pressurization

[Lars_J]

Exactly - there is always some risk. Certain failure modes will always be fatal. You just have to learn to manage it properly, and not become overzealous about it. Otherwise I would suggest not walking across the street or driving a car.

[Borklund]

Really? A flight to that altitude with no apparent plan B if the cabin is depressurized?

This was my exact reaction. There's definitely no full or partial pressure suits, but didn't ask about oxygen masks (I would assume that they are out too; if they rely on the windows not breaking in space they might as well rely on them not to break in atmosphere). What they are going to do is rely entirely on the cabin pressure holding and if you think about what Branson has been saying, liking his trips to to early airline flights, it makes at least a little sense. A partial pressure suit with a parachute and survival pack is 10-20 kg and six of them is basically another passenger in just extra bulk mass. Consider the already razor thin margins of getting just 6 passengers to space for a brief moment and it doesn't add up.

[Chris Bergin]

 FOR IMMEDIATE RELEASE

Jan. 23, 2014

 

VIRGIN GALACTIC ANNOUNCES SUCCESSFUL TEST FIRINGS OF NEW LIQUID ROCKET ENGINES FOR LAUNCHERONE

Company developing rocket engines designed and built in house

for its affordable, responsive small satellite launch service

 

MOJAVE, Calif. – Virgin Galactic, the world’s first commercial spaceline, announced today that it has reached a significant milestone in the testing of a new family of liquid rocket engines for LauncherOne, the company’s small satellite launch vehicle.  As part of a rapid development program, Virgin Galactic has now hot-fired both a 3,500 lbf thrust rocket engine and a 47,500 lbf thrust rocket engine, called the “NewtonOne” and “NewtonTwo” respectively.  Further, the NewtonOne engine has successfully completed a full-mission duty cycle on the test stand, firing for the five-minute duration expected of the upper stage engine on a typical flight to orbit.  These tests are being conducted on two new state-of-the-art test stands that the team designed, assembled and installed internally.

 

“We are proud of the great progress our propulsion team has made in reaching these milestones,” said Virgin Galactic CEO George Whitesides.  “Combined with parallel progress made by the company in advanced tank and avionics technology, we are now well on our way to providing customers with the lowest cost opportunity for small satellite manufacturers and operators to buy a dedicated ride to space.”

 

The new rocket engines were designed and assembled in-house by Virgin Galactic engineers and technicians, and mark the first firings of engines designed and built by the privately-funded company, owned by Sir Richard Branson’s Virgin Group and Abu Dhabi’s aabar Investments PJS.

 

As part of the ongoing test program, the NewtonOne engine has now been fired dozens of times, achieving the target thrust during a full-duration test. The test team has successfully completed as many as six distinct test firings in a single day, as a demonstration of the rapid test-retest capability critical to the liquid engine program. The larger NewtonTwo engine has also been fired multiple times at short duration, with longer duration firings scheduled to occur in the coming months. Additionally, Virgin Galactic engineers and technicians successfully completed a quick turnaround test in which engines were swapped out and fired within 12 hours, an important early demonstration of LauncherOne’s responsive, quick call-up capability and of the versatility of both the engines and the test stand.

 

“The unique environment in Mojave enables the team to design, manufacture, assemble and test the engines in a single location, which allows us to make progress swiftly,” said Whitesides.

 

Both engines were custom-designed by Virgin Galactic to serve as the propulsion system for the LauncherOne satellite launch vehicle, which uses a single NewtonOne on the upper stage and a single NewtonTwo on the main stage. Both engines are simple, pressure-fed LOX/RP-1 systems built with a low part-count design. The NewtonTwo engine is a scaled-up version of the NewtonOne, sized to serve as the first stage engine for LauncherOne, with a nozzle optimized for air-launched performance. Powered by those two engines, LauncherOne will carry small satellites to low-Earth orbit affordably and responsively, enabling a new generation of private and government missions.

[jabe]

anyone else find this "funny"  ?
SS2 may not have a motor yet but they have an all liquid engine quickly being developed  for the Launcher one rocket?
let the discussion begin on the oddity of it all.. or it is at least odd to me...
jb

[mr. mark]

Last time I checked SS2 has had 3 in flight motor burns and they seemed to go just fine. As far as some people not thinking that they like the engine or don't find the engine test results transparent well... that's their beef.