Virgin Galactic and SpaceShipTwo Master Thread (1)

[Ronsmytheiii]

Ok, I won't accept a simple no. Then what would be the maximum glide distance using spaceship 2 from it's maximum flight height?

The X-15 had a range of about 280 miles, which is not that much. Spaceshipone could only go about 40 miles. Spaceship two might fly a bit faster/higher, but It will not go much further.

[William Barton]

Ok, I won't accept a simple no. Then what would be the maximum glide distance using spaceship 2 from it's maximum flight height?

The X-15 had a range of about 280 miles, which is not that much. Spaceshipone could only go about 40 miles. Spaceship two might fly a bit faster/higher, but It will not go much further.

What's the maximum altitude you could have gliding flight in a vehicle like that. Maybe 20mi? Since SS1 went more or less straight up, it's maximum altitude would be irrelevant anyway. You could lob it to GEO and let it fall back and it wouldn't try to "glide" until it go back inside the atmosphere.

[mlorrey]

Ok, I won't accept a simple no. Then what would be the maximum glide distance using spaceship 2 from it's maximum flight height?

The X-15 had a range of about 280 miles, which is not that much. Spaceshipone could only go about 40 miles. Spaceship two might fly a bit faster/higher, but It will not go much further.

According to Rutan's presentation at EAA Oshkosh: "11) SpaceShip One flew straight up, and recovered straight down. SpaceShip Two will fly 200 to 300 miles down range. Rutan anticipates that Virgin will launch SpaceShip Two over the Pacific Ocean and recovering it at Mohave. This will provide several minutes of atmospheric flight at Mach 2-3 during ascent and descent, providing a Concorde like experience."

Ron's conclusion is highly dependent up on the wing loading of SS2 vs X-15. I am reading a source saying the wing loading was 75 lb/sqft on the X-15 on reentry with an L/D of 4 from what I've been reading. SS1 was 49 lb/sqft, I assume SS2 will have something similar tho I've got no data on this. SS2's main issue with long downrange distance is that the feathering reentry system mitigates against doing high speed skips off the atmosphere, it's designed to present the most high drag angle of attack possible in a stable configuration, so is meant to bleed speed and give up range.

You would thus need to redesign SS2 to be a skip diver (or maybe just train the pilots to do so with the existing vehicle and only engage the feathering when they are ready to land).

Also note that X-15's long range trips happened at lower altitude when they were going for high speed. Their high altitude trips above 300,000 ft were typically flown in a lower speed range.

[Jorge]

Ok, I won't accept a simple no.

I do not care what you will or will not accept.

Then what would be the maximum glide distance using spaceship 2 from it's maximum flight height?

Well short of Mojave to White Sands, I can tell you that.

[mr. mark]

"According to Rutan's presentation at EAA Oshkosh: "11) SpaceShip One flew straight up, and recovered straight down. SpaceShip Two will fly 200 to 300 miles down range. Rutan anticipates that Virgin will launch SpaceShip Two over the Pacific Ocean and recovering it at Mohave. This will provide several minutes of atmospheric flight at Mach 2-3 during ascent and descent, providing a Concorde like experience."

Ron's conclusion is highly dependent up on the wing loading of SS2 vs X-15. I am reading a source saying the wing loading was 75 lb/sqft on the X-15 on reentry with an L/D of 4 from what I've been reading. SS1 was 49 lb/sqft, I assume SS2 will have something similar tho I've got no data on this. SS2's main issue with long downrange distance is that the feathering reentry system mitigates against doing high speed skips off the atmosphere, it's designed to present the most high drag angle of attack possible in a stable configuration, so is meant to bleed speed and give up range.

You would thus need to redesign SS2 to be a skip diver (or maybe just train the pilots to do so with the existing vehicle and only engage the feathering when they are ready to land).

Also note that X-15's long range trips happened at lower altitude when they were going for high speed. Their high altitude trips above 300,000 ft were typically flown in a lower speed range".

Thank you, This is the information I was looking for.

[Nomadd]

 I think the X-33 was going to have a 1200 mile range or so. Anybody remember what sort of profile that was going to be?

[douglas100]

I believe that SS2's vertical flight profile with feathering is designed to minimise re-entry heating. Trying to fly it at mach 3 horizontally might overload its current TPS.

[bad_astra]

SS1 just has a small ablative coating on the wings. That would not work on a transatlantic flight. You would need some kind of heat-sink shield.

Len Cormier did a lot of work on a point-to-point system. I forget the name of it, but it basically did the kind of power-skip-glide kind of flight that seems to be discussed here. 

[DaveJes1979]

Guys, do the math on ballistic trajectories.  For a hop from New York to Paris (the old Concorde route), the required delta V is 6100 m/s.  This is without even counting gravity and drag losses.  That comes out to 61% of orbital delta V.  This is vastly beyond what any SS2-type system is capable of.  Any configuration with that kind of performance will look very much like an orbital LV system.

Of course it would be very nice - the coast phase of your trip would only be 23 minutes.

But consider that modern airliners have far longer ranges than the NY-Paris route.  LA-Paris would require 6900 m/s delta V (plus drag & grav losses), or 78% of orbital delta V.  LA-Sydney would be 7400 m/s (90%).  The cost, size, and complexity of any system that could reach these distances would be nearly indistinguishable from orbital LVs and spacecraft.

[Robotbeat]

Guys, do the math on ballistic trajectories.  For a hop from New York to Paris (the old Concorde route), the required delta V is 6100 m/s.  This is without even counting gravity and drag losses.  That comes out to 61% of orbital delta V.  This is vastly beyond what any SS2-type system is capable of.  Any configuration with that kind of performance will look very much like an orbital LV system.

Of course it would be very nice - the coast phase of your trip would only be 23 minutes.

But consider that modern airliners have far longer ranges than the NY-Paris route.  LA-Paris would require 6900 m/s delta V (plus drag & grav losses), or 78% of orbital delta V.  LA-Sydney would be 7400 m/s (90%).  The cost, size, and complexity of any system that could reach these distances would be nearly indistinguishable from orbital LVs and spacecraft.

_{From here: http://www.pp.htv.fi/jwestman/space/sang-e.html}

Here's a design (single-stage) from World War 2.0:
http://en.wikipedia.org/wiki/Antipodal_bomber

[bad_astra]

IIRC, Cormier's plan was not a simple ballistic trajectory.

[kevin-rf]

Article on making the right call and ending the after party early: http://www.bakersfield.com/news/local/x113237093/Supervisors-hear-details-of-harrowing-tent-collapse

[Nascent Ascent]

Let's say that somehow you could get the SS2 into orbit. Would SS2's feathering technology and configuration allow it to reenter from orbit.

In other words, will Rutan's next step for a true orbital vehicle require not only additional booster power but a new reentry system as well?

[Jorge]

Let's say that somehow you could get the SS2 into orbit. Would SS2's feathering technology and configuration allow it to reenter from orbit.

No. Additional TPS would be required.

In other words, will Rutan's next step for a true orbital vehicle require not only additional booster power but a new reentry system as well?

Rutan could still use the feathering system and that might help reduce heating loads, but he simply cannot get away without using a real TPS for an orbital vehicle.

[mlorrey]

I believe that SS2's vertical flight profile with feathering is designed to minimise re-entry heating. Trying to fly it at mach 3 horizontally might overload its current TPS.

This depends on the altitude it is flying mach 3 at. If its skipping off the top of the atmosphere at mach 3, it wont overload it at all. This is all a function of wing loading. The lower your wing loading, the higher up you can skip and avoid heating. Shuttle gets hot because its 96 lb/sqft wing loading causes it to plummet deep into the atmosphere before it starts decellerating appreciably (below 200k ft). If SS2's reentry wing loading is below 40 lb/sqft, then at mach 3 it will be just fine.

[Herb Schaltegger]

I believe that SS2's vertical flight profile with feathering is designed to minimise re-entry heating. Trying to fly it at mach 3 horizontally might overload its current TPS.

This depends on the altitude it is flying mach 3 at. If its skipping off the top of the atmosphere at mach 3, it wont overload it at all. This is all a function of wing loading. The lower your wing loading, the higher up you can skip and avoid heating. Shuttle gets hot because its 96 lb/sqft wing loading causes it to plummet deep into the atmosphere before it starts decellerating appreciably (below 200k ft). If SS2's reentry wing loading is below 40 lb/sqft, then at mach 3 it will be just fine.

"Mach 3" is a meaningless term in the absence of temperature, pressure and density values.

[jhoblik]

My first impression of SS2 was , looks like smaller version of space shuttle. I could easy imagine it with TPS and  could breaking from orbit with less heat and less danger for crew.

[mlorrey]

I believe that SS2's vertical flight profile with feathering is designed to minimise re-entry heating. Trying to fly it at mach 3 horizontally might overload its current TPS.

This depends on the altitude it is flying mach 3 at. If its skipping off the top of the atmosphere at mach 3, it wont overload it at all. This is all a function of wing loading. The lower your wing loading, the higher up you can skip and avoid heating. Shuttle gets hot because its 96 lb/sqft wing loading causes it to plummet deep into the atmosphere before it starts decellerating appreciably (below 200k ft). If SS2's reentry wing loading is below 40 lb/sqft, then at mach 3 it will be just fine.

"Mach 3" is a meaningless term in the absence of temperature, pressure and density values.

Yes, and pressure and density is important when it comes to wing loading. The higher the wing loading, the higher the pressure and density must be (i.e. lower altitude) before the vehicle can either decellerate significantly or skip off the atmosphere. The lower that altitude is, the higher your skin temperature will get. A vehicle at mach 3 at sea level will see a LOT more friction and thus heating than when flying at 100k ft.

[DiggyCoxwell]

It takes much longer than expected for Virgin Galactic to take off
but anyway wish them the best luck
Virgin Galactic is among the very few highly credible and serious space tourism companyies, along withcompanies like SpaceX and Bigelow Aerospace

There's a new update for the White Knight Two Test Log,
dated January, 28, 2010.
  They are now testing the WK2 and SS2 combination,
but is it just runway tests or actual capture carry flights?

[jabe]

There's a new update for the White Knight Two Test Log,
dated January, 28, 2010.
  They are now testing the WK2 and SS2 combination,
but is it just runway tests or actual capture carry flights?

I read the log

Objectives:       
Launch pylon envelope expansion and performance effects
Landing gear door evaluation
SpaceShipTwo approach guidance evaluation
Pilot proficiency
Results:
Launch pylon and gear doors performed well. Multiple SpaceShipTwo approaches flown.

as they added the pylon (SS2 wasn't captive carried) that helps attach SS2 to the wk2 and checked how it affects flight..
and then flew WK2 as if it is SS2 since it is supposed, if I understand it right, to mimic a lot of SS2 characteristics. cockpit layout, field of view....
my 2 cents on the update...
jb