X-37B crew launcher

[Antares]

Well, wait.  The Administrator said something like we don't cut the Navy to pay for hurricane damage, when asked about NASA funding after Katrina.  So some evidently think NASA is like the armed forces in some ways.  We can't have it both ways, i.e. a protected, military-like program and one that is also risk-averse, civilian.

[Analyst]

Best of both worlds: Civilian, e.g. not protected (Why should NASA be something special, why the military?), and not risk averse. Is this too much to ask?

Analyst

[MrTim]

Airliners do not have passive abort capabilities either, but we put an amazing number of innocent, unsuspecting men, women, and children on to them every year. Funny that when I point out how insanely risk-averse our society is getting, people get upset and argue that we have not become that risk-averse, but when somebody suggests a winged RLV, the risk-aversion argument arises.

(snip) Airliners have multiple engines and continue takeoff with one engine out, they can go around, they can glide, etc.  Airliners  have systems with redundancy to allow them to survive almost problems except for ones caused by outside influences (i.e. collision, very severe weather, pilot error, bombs).  A 767 completely ran out of fuel do to a loading error and yet was able to glide to a safe landing with it hydraulics powered by a deployable generator

Wrong. There are no airliners which can make an uncontrolled safe descent based purely upon aerodynamic forces. Deprived of aircrew and avionics there is no airliner that will make anything other than a smoking hole upon touchdown from 20k ft. There is nothing passive about anything you cited; these examples are all good arguments in favor of a winged vehicle with no passive abort modes, a pilot aboard, redundant flight controls and some Level-A avionics.

Fighter aircraft who are subject to outside influences have ejection seats.

Even a perfect seat cannot get a pilot out of every possible situation, so this is an argument in favor of a winged vehicle provided things like ejection seats can reduce, but not eliminate, the black zones. An ejection seat has nothing to do with a passive abort and was not even part of the discussion, so I'm not sure what this is doing here.

I would call gliding passive abort capability.  Airlines always keep their nose forward.  They don't try to fly tail first.   That is all what passive abort and passive entry mean. (snip)

You can call that a passive abort mode if you like, but that just don't make it so. Deprived of aircrew and autopilot, those big shiny airliners will not make a nice safe straight-and-level descent to a touchdown. A capsule may be designed to self-stabilize  without input from a pilot or an autopilot, but a completely uncontrolled airliner will eventually depart from stable flight. Period. A real airframe is not a mathematical model in perfect trim and balance and it is subject to weather, turbulence, etc. An aircraft which remains in level flight while someone or something is applying control inputs cannot, by any stretch, be referred to as being in a "passive abort" mode. As for an engine loss on departure... I have never heard anybody call that procedure a "passive abort". 

[Jim]

1.  Deprived of aircrew and avionics there is no airliner that will make anything other than a smoking hole upon touchdown from 20k ft. There is nothing passive about anything you cited;

2.  these examples are all good arguments in favor of a winged vehicle with no passive abort modes, a pilot aboard, redundant flight controls and some Level-A avionics.

3.  Even a perfect seat cannot get a pilot out of every possible situation, so this is an argument in favor of a winged vehicle provided things like ejection seats can reduce, but not eliminate, the black zones. An ejection seat has nothing to do with a passive abort and was not even part of the discussion, so I'm not sure what this is doing here.

4.  You can call that a passive abort mode if you like, but that just don't make it so. Deprived of aircrew and autopilot, those big shiny airliners will not make a nice safe straight-and-level descent to a touchdown. A capsule may be designed to self-stabilize  without input from a pilot or an autopilot, but a completely uncontrolled airliner will eventually depart from stable flight. Period. A real airframe is not a mathematical model in perfect trim and balance and it is subject to weather, turbulence, etc. An aircraft which remains in level flight while someone or something is applying control inputs cannot, by any stretch, be referred to as being in a "passive abort" mode. As for an engine loss on departure... I have never heard anybody call that procedure a "passive abort". 

1.  That's were you wrong again Who said crew was part of the issues but anyways.  Airliners will always have extra crew* and avionics (and electrical and hydraulic power)  because it can afford the extra weight.  Passengers are even a backup. 

2.  An ejection seat is part of the argument because it is an abort system for an aircraft

3.  I never said gliding is  passive.  It is "equivalent" to passive abort.   It is the last resort after other failures.

But gliding is passive wrt to propulsion.  Without propulsion, a airliner or capsule can land. 

4.  Been there, done that




 

[kevin-rf]

Don't know, one of the now retired F-106's did a passive landing in a Montana after the plane entered a spin and pilot ejected.

http://www.f-106deltadart.com/71fis.htm

I do remember seeing an article once on it being pressed back into service after the incident.

I would call that pretty passive.

 

[nobodyofconsequence]

...
BTW:  the BD-5 is certainly at the low-end of the manned-vehicle size range, but it is indeed a real aircraft and one person fits in it just fine (albeit sans space suit, etc. ) .... in case somebody thinks it was just some sort of movie prop.
...

Knew someone who routinely flew one. Used a shaving kit bag stuffed under the knees as his "baggage". Said that if he added a toothbrush or pen, he could feel the difference. More like wearing a plane than flying in one ...

[possum]

Don't know, one of the now retired F-106's did a passive landing in a Montana after the plane entered a spin and pilot ejected.

http://www.f-106deltadart.com/71fis.htm

I do remember seeing an article once on it being pressed back into service after the incident.

I would call that pretty passive.

 

There was a DC-3 in World War II that landed itself in a field after the crew bailed out due to severe damage in flight.  But they don't make them like that anymore, and it was flying lower than 20K ft.

[Patchouli]

No, you have to have a vehicle shape that rights itself up in case the vehicle takes a dive in the atmosphere belly up.

BTW is that true that Orion doesn't have a passive reentry mode, because of center of gravity issues?

It should be noted Apollo could not perform a passive reentry during a lunar return.
During lunar return it had to function as a lifting and steerable craft.
I remember one of the Apollo astronauts mentioning this during a documentary.
 If the angle was wrong etc it would either bounce back into space or dive too deeply into the atmosphere and the Gs would build up to around 20g and then the vehicle would be crushed.
But at least you wouldn't be conscious by the time that happens.

[kevin-rf]

There was a DC-3 in World War II that landed itself in a field after the crew bailed out due to severe damage in flight.  But they don't make them like that anymore, and it was flying lower than 20K ft.

You are right, I think the point is, some planes can and do have passive modes that let the glide in with no input on the controls.

One thing I have always loved about the Rutan Long EZ design is with the forward canard allows a passive failure mode where the canard will stall before the wing preventing stalls.

I guess the question comes down to, "can a non capsule winged shape have passive reentry at hypersonic speeds."

Rutan got around the problem on the SS-1 using the shuttle cock, but the speeds where not orbital, much less lunar...

[Jim]

It should be noted Apollo could not perform a passive reentry during a lunar return.
During lunar return it had to function as a lifting and steerable craft.
I remember one of the Apollo astronauts mentioning this during a documentary.
 If the angle was wrong etc it would either bounce back into space or dive too deeply into the atmosphere and the Gs would build up to around 20g and then the vehicle would be crushed.
But at least you wouldn't be conscious by the time that happens.

Incorrect as usual.  passive entry has nothing to do with the entry angle.  The CM (nor any capsule) can not control the entry angle.  That is a function of the SM

[Free2Think]

All of this discussion about safest options, passive abort and roomy accommodations is interesting but in my opinion is avoiding the real issue.  Under NASA’s current plan America will rely on Soyuz for crew access to ISS until 2015. Based on the last 4 years of NASA led Ares/Orion development this is only likely to get longer.  Yes, we can hope and pray that Falcon/Dragon will come in and save the day but do we really want to bet America’s $100B national space laboratory on SpaceX?

The Soyuz is extremely cozy to say the least and has had serious reentry issues on the last two missions.  Yes, the X-37B is small and not perfect, but is it good enough?  I would think that a X-37B minimal derivative crew vehicle might be able to fly on an Atlas in under 3 years.  This seems like a very attractive near term alternative.  This certainly provides a viable cargo return option.

Some interesting details on the X-37B:
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/aw080408p2.xml

[vt_hokie]

The Soyuz is extremely cozy to say the least and has had serious reentry issues on the last two missions.  Yes, the X-37B is small and not perfect, but is it good enough?  I would think that a X-37B minimal derivative crew vehicle might be able to fly on an Atlas in under 3 years.  This seems like a very attractive near term alternative. 

That's been my preferred path ever since the OSP days.  It seems to make a lot of sense for an agency that simply doesn't have the funding for the lunar program that seems to be on life support.

[Jim]

I would think that a X-37B minimal derivative crew vehicle might be able to fly on an Atlas in under 3 years. 

A lot longer.    Not even 3 years before drop tests.  Nothing from the current vehicle is usable except the shape

There would be bigger issues.  A larger winged vehicle couldn't fit in the fairing.  Wing vehicle on an LV causes control problems

[Lampyridae]

HL-20 / X-38 is a much better design for human use than X-37B.

-lower g loading
-more stable re-entry (less angle of attack control required)
-lower heat loading on nose, leading edges
-has been studied to death (was heavily based on Russian design with several reentry tests)
-designed for humans from the start: life support, windows, abort engines
-will probably fly anyway as Dreamchaser

If you really, really want to launch a human into space with an X-37B you can put somebody in a spacesuit in a couch inside the cargo bay and pray. This would be some sort of Apollo-13 "put a square peg into a round hole" emergency though.

[Propforce]

Maybe it is time for NASA to consider an X-37B derivative for a near term crew vehicle.  X-37B is flying this November on an Atlas. http://www.aviationweek.com/aw/generic/story.jsp?id=news/SPACE07298.xml&headline=USAF%20Sets%20Orbital%20Spaceplane%20Test%20Flight&channel=space

This is an old and tired subject
NASA did consider for OSP and it lost to the capsule design.  Wing vehicles do not have passive abort and entry capabilities 

Well... I don't believe the issue is as simplistic as you've stated.

1) The X-37B is small enough to be place inside of an Atlas V fairing.  This solves a whole bunch of launch issues & risks associated with non-fairing launch of bigger size P/L sitting on top of an Atlas V (as depicted in the OSP program).  Apples & oranges.

2)  Wing vs capsule designs really has to do with other figure of merits, such as cross-range capability of your reentry vehicle (RV), CONOPS, as well as the state of key critical technologies readiness, e.g., wing leading edge TPS, etc. Some of these technologies, such as TPS, were not ready then.

3)  The X-37B is a 'risk reduction' flight test as one step closer to a reusable re-entry vehicle for operations.  NASA could not afford to take this risk for the CEV (Orion) from both schedule & publicity point of view.

[Propforce]

People seem to be thrown off by the TPS and aerodynamic shape of the vehicle into thinking that the X-37 is like the shuttle.  Rather think of it as a recoverable satellite.  Put an imaging system or EW package inside, then launch it when needed over a battlefield.  That way you can quickly and relatively cheaply orbit much needed battlefield awareness over a hot spot to provide battle preparation and/or battle assessment.

Yes, but why design a recoverable satellite with wings? 

[FunFlying]

The grass is always greener on the other side.  Some may view Dreamchaser as a better option, or OSP or any number of other studies.  Today, Dreamchaser is nothing more than a mockup and some 40 year old wind tunnel tests, OSP is a pile of aging paper weights.  X37B will be the real enchilada in a couple of months.  Stop moaning over what could be, what should be.

[vt_hokie]

I'd be curious to know how the development cost of the HL-20 derived Dreamchaser/Atlas V system compares with that of Ares I/Orion.

[lewis886]

This is an old and tired subject
NASA did consider for OSP and it lost to the capsule design.

Yes, and NASA chose the Ares I too...   let's ponder how well that's turned out thus far   



(not ragging on you jim, just the Ares I   haha)

[nobodyofconsequence]

... Nothing from the current vehicle is usable except the shape ...

TPS? Avionics? Airframe? Orbital test of flight systems? Successful launch and reentry?