Sierra Nevada Thread (Dream Chaser, plus!)

[tater]

OK, this will be the Dream Chaser thread for updates, and eventually flight (launches will be ULA, but CST-100 has a thread, so so should this).

 

 

 

Edited August 21, 2019 by tater

[Mad Rocket Scientist]

Looks like you have a few options, but none with great titles:

They seem to either to be very old, or have not great titles. You may just want to start a new one.

[tater]

OK, I'll use this thread (re-titled).

 

 

 

 

[Green Baron]

This is a nifty thing. Finally a spacecraft the pleases the eye equally as at serves a purpose.

I mean, really :-)

Edited October 1, 2018 by Green Baron

[OrbitsR4Sissies]

Sierra Nevada doesn't get the credit it deserves as a spacecraft developer and integrator. They don't usually serve as the primary contractor of a space probe, but they design so many components used in many popular spacecraft, including:

• Mars InSight Lander (arriving next month, November 2018)
• Parker Solar Probe
• ORBCOMM 2 satellites
• Many reaction control systems for satellites

I'm happy that SNC got this resupply contract. I'm not big into spaceplanes in KSP but I like the idea of a reusable winged refueler with a reusable booster to save funds in the game. The DC Cargo's look is my inspiration.

[Nightside]

If they don’t get much credit it may  be that they don’t seek much attention. Their website is pretty targeted to military applications so much of their work is probably secret. SNC also designed the Rocket Motor 2 -for the ill-fated SpaceShip2, although the failure of that craft was not related to the engines.

 

Does anyone know how Dream Chaser compares to the x37b? 

[mikegarrison]

59 minutes ago, Nightside said:

Does anyone know how Dream Chaser compares to the x37b? 

The X-37 has actually flown in space.

Edited October 2, 2018 by mikegarrison

[OrbitsR4Sissies]

2 hours ago, Nightside said:

If they don’t get much credit it may  be that they don’t seek much attention. Their website is pretty targeted to military applications so much of their work is probably secret. SNC also designed the Rocket Motor 2 -for the ill-fated SpaceShip2, although the failure of that craft was not related to the engines.

 

Does anyone know how Dream Chaser compares to the x37b? 

The Dream Chaser is based on NASA's HL-20 lifting body concept, which was considered as an intermediate less-costly option for resupply and crew transport to and from the planned International Space Station.

The X-37B has a similar NASA origin as they studied smaller lifting bodies. It was moved over to the Department of Defense, became a very classified project, and gave the Air Force what they have been clamoring for since the old Dyna-Soar project: Eyes in the sky that they can use for almost any project with little attention.

Edited October 2, 2018 by OrbitsR4Sissies

[tater]

 

[Mad Rocket Scientist]

https://twitter.com/i/broadcasts/1vAGRyPOlRrKl

[insert_name]

SNC has been cleared to start production

https://spacenews.com/dream-chaser-cleared-to-begin-full-scale-production/

[Nightside]

1 hour ago, insert_name said:

SNC has been cleared to start production

https://spacenews.com/dream-chaser-cleared-to-begin-full-scale-production/

Keeping the spaceplane dream alive!

[DDE]

9 hours ago, Nightside said:

Keeping the spaceplane dream alive!

It’s a damned zombie. Many a bright head smashed itself against the wall, repeatedly, since the 1950s, trying to make them practical.

[Ozymandias_the_Goat]

3 hours ago, DDE said:

It’s a damned zombie. Many a bright head smashed itself against the wall, repeatedly, since the 1950s, trying to make them practical.

That’s why I can’t say I’m particularly excited about this. Spaceplanes simply do not work as well as rockets, and there is simply no point to waste mental resources trying to make this superficially interesting, but fundamentally flawed concept “aloft”.

Edited December 19, 2018 by Ozymandias_the_Goat

[insert_name]

1 hour ago, Ozymandias_the_Goat said:

That’s why I can’t say I’m particularly excited about this. Spaceplanes simply do not work as well as rockets, and there is simply no point to waste mental resources trying to make this superficially interesting, but fundamentally flawed concept “aloft”.

rockets are a type of propulsion, spaceplanes are a type of reentry vehicle, the two are not mutually exclusive. in this case, the space plane design helps reduce recovery time and g loads during reentry, while it launches on an atlas V,  a regular old rocket.

Edited December 19, 2018 by insert_name

[Ultimate Steve]

And plus, spaceplanes look really freaking cool.

Which isn't a major justification for building one, but I wish it was.

[DDE]

11 hours ago, insert_name said:

rockets are a type of propulsion, spaceplanes are a type of reentry vehicle, the two are not mutually exclusive. in this case, the space plane design helps reduce recovery time and g loads during reentry, while it launches on an atlas V,  a regular old rocket.

Perhaps tbe appropriate term would be “rocketship”, then.

It’s the kind of old-timey term that brings all the Musketeers to the yard.

[Scotius]

In Poland, we use(d) the term "Rakietoplan". "Rocketplane" is a direct translation. I kinda like the sound of that

[DDE]

Just now, Scotius said:

In Poland, we use(d) the term "Rakietoplan". "Rocketplane" is a direct translation. I kinda like the sound of that

Here-here. But we have to placate the Heinlein fans.

[Ozymandias_the_Goat]

19 hours ago, insert_name said:

rockets are a type of propulsion, spaceplanes are a type of reentry vehicle, the two are not mutually exclusive. in this case, the space plane design helps reduce recovery time and g loads during reentry, while it launches on an atlas V,  a regular old rocket.

True, I suppose I should have been more specific about what I meant by “rocket” and in that I meant a regular capsule and booster system. So, to continue, yes, the dream chaser launches aboard an atlas v or Vulcan, that is still an expendable vehicle, so I’m not too keen on its routine use. And as for  the space plane itself, I suppose that it could reduce the rentery force somewhat, but as for refurbishing it, how is it cheaper than a capsule? I don’t know, perhaps the bad experiences with the shuttle program tend to make one biased towards the space plane concept, but until they can actually beat out traditional launch vehicles in practice, I remain unconvinced of their worth.

[tater]

The X-37 has flown a few times, and been reused. CST-100 is set to be reused (a capsule), and Dragon gets reused (and it gets dunked in the sea).

Dream Chaser is a great idea.

[DDE]

4 hours ago, Ozymandias_the_Goat said:

but as for refurbishing it, how is it cheaper than a capsule?

It's about heat shield material, TBH. With ablative, into the trash it goes, after every flight. You could posit that a ceramic non-expendable TPS is easier on a spaceplane, though.

[NSEP]

There are several advantages spaceplanes have over regular cone/bell shaped capsules, they reduce the g-forces, but they also also have more control over where they land, regular capsules usually land in a desert/ocean and have to be transported from there all the way to the place it has to be refurbished, while spaceplanes can just glide back, to a runway right next to the place its supposed to be built.

There also is some sort of 'size limit' for space capsules. At some point, the parachute for such a thing is simply going to be too heavy and would have to resort to a propulsive landing, and the diameter would too large to fit on any existing rocket. The 'size limit' of a spaceplane is much higher, since it doesn't need to use parachute in the first place and can slowly glide to a soft landing, and because spaceplanes are more elongated, they have a much higher volume per diameter.

[DDE]

16 hours ago, NSEP said:

regular capsules usually land in a desert/ocean and have to be transported from there all the way to the place it has to be refurbished

I generally lump in retroprops with regular calsules, and Dragon 2 used to have pinpoint landing capability.

Not sure with Zarya, which would have been a useful datapoint as a program parallel to a spaceplane.

16 hours ago, NSEP said:

There also is some sort of 'size limit' for space capsules. At some point, the parachute for such a thing is simply going to be too heavy and would have to resort to a propulsive landing

That point has long since passed, and Voskhod surmounted it with little issue.

16 hours ago, NSEP said:

and the diameter would too large to fit on any existing rocket.

Most manned craft are built alongside their boosters. And if N-1 and Convair Nexus are of any indicator, diameter is not a principle obstacle.

Plus you have the option of extending heatshields or “manned Falcon” style retropropulsion rocketships.

[kerbiloid]

Also

***

The bigger is your capsule, the greater is its mass to cross-section area ratio (square-cube law).

So, the bigger is your capsule, the flatter you want it to be to keep it gliding, not falling.
At the limit you want a glider: either a flying source or a winged body or a lifting body.
The Spiral/DreamChaser design is a compromise.

***

The bigger is your capsule, the greater is its rotation radius if it overturns. So, the greater can be the injuries.
The more people you want to send, to weaker are the health requirements, the less you want it to overturn, full of civil weaklings.
So, you want either a rocket landing, or a glider.

***

The bigger is your capsule, the more people fly in it, the more you need a restroom.
The bigger is your capsule, the less you need a separated module for it and for cargo (like in Soyuz), the more you want to place this right in the capsule itself.
This in turn makes it heavier and more bulky, so you additionally want to make it gliding.

***

The more people is sitting in your capsule, including the civilians, the less you want it to land on a mountain cliff, or in the winter lake covered with snow, or in the middle of ocean.
So, you want it to glide, again.

***

So, when your space traffic rises, you want a spaceplane instead of a capsule.
And you start wanting a DreamChaser instead of a capsule.

***

But then you realise that the, while all those cargo, toilet, docking node, orbital engines, solar panels, life support are required only in orbit, so can be placed in a separated compartment.
While all advantages of the gliding are required only for the crew. As well as the overweighted LES engines,
Then you want a Hermes or a Clipper, with a service module containing heavy systems, attached to the rear side of a relatively small mini-plane with the crew.

***

But then you realise that the greed makes you to want to have the service module reusable, so I guess the next step will be a binary ship consisting of a mini-plane with the crew seats and a heavy capsule of a reusable service module performing a ballistic descent and landing on chutes .