CRS-2 Contenders- Who do you think will get the contract?

[Streetwind]

This is so wrong, it's not even funny.

The Cargo Dragon can only carry ~3.5T to the ISS. Falcon 9 1.0 can carry 10 T to LEO. The smallest Atlas V is 8T to LEO. CST-100 is 13T, too big for V1.1.

...What the what?

- Cargo dragon's upmass: What relevance does that have in relation to anything at all that I have said? I've not made any claims in regards to its performance.

- Falcon 9 v1.0 payload to LEO: Yes, what you said is literally the exact same thing as I wrote. Not sure where in that part I am "so wrong it's not even funny"?

- Atlas V payload to LEO: Got a source for your 8T? Because I have one for 9,050 kg and one for 9,800 kg, the variation likely being due to different reference orbit heights being used. 8 tons sounds more like a polar orbit.

- CST-100 mass: Again, source? 13 metric tons cannot possibly be true. I can't find a useful source myself, but I can find one for the Crew Dragon, which lists a dry mass of 4.2 tons plus 3.3 tons of usable payload. Even if CST-100 is 'built tough' and heavier than its peers, it is still a vehicle that has roughly the same diameter, the same crew capacity and very similar in-space performance specs - which implies similar weight, because Boeing is generally pretty good about building spacecraft. The notion that it would weigh more than three times is simply absurd. Even Orion only masses 10.4 tons.

Please, if you do insist on being rude, at least have the decency to make sense and be correct.

[Nibb31]

Well, Dream Chaser has the benefit off of being based off of HL-20, so there are less R&D than Dragon when they were first being made.

Dream Chaser is also actually lighter than CST-100 and Dragon, so it uses a cheaper booster. Also, it could launch on a Falcon 9 if they wanted too- it was proposed when the spacecraft was first being built.

What was proposed at the project's inception, what has been developed, and what SpaceX is willing to sell are 3 different things.

The Dream Chaser is great for tourism- I mean, who wouldn't want to ride on something looking that cool?

I don't believe in a tourism market that relies on launching off an Atlas V.

It is favoured by the DOD an tourism, to have wings, though.

The DoD isn't interested in manned spaceflight. Tourism is a sector that has yet to prove its sustainability, and Jeff Bezos disagrees with the wings statement.

[fredinno]

...What the what?

- Cargo dragon's upmass: What relevance does that have in relation to anything at all that I have said? I've not made any claims in regards to its performance.

- Falcon 9 v1.0 payload to LEO: Yes, what you said is literally the exact same thing as I wrote. Not sure where in that part I am "so wrong it's not even funny"?

- Atlas V payload to LEO: Got a source for your 8T? Because I have one for 9,050 kg and one for 9,800 kg, the variation likely being due to different reference orbit heights being used. 8 tons sounds more like a polar orbit.

- CST-100 mass: Again, source? 13 metric tons cannot possibly be true. I can't find a useful source myself, but I can find one for the Crew Dragon, which lists a dry mass of 4.2 tons plus 3.3 tons of usable payload. Even if CST-100 is 'built tough' and heavier than its peers, it is still a vehicle that has roughly the same diameter, the same crew capacity and very similar in-space performance specs - which implies similar weight, because Boeing is generally pretty good about building spacecraft. The notion that it would weigh more than three times is simply absurd. Even Orion only masses 10.4 tons.

Please, if you do insist on being rude, at least have the decency to make sense and be correct.

Ok, I guess I didn't understand you then. Sorry.

Atlas V 501 is 8T to LEO. http://spaceflight101.com/spacerockets/atlas-v-501/

CST-100 is 13T total mass, capsule, solar panels, fuel, and all. http://space.skyrocket.de/doc_sdat/cst-100.htm

Orion is around 25T if you count total mass. https://en.m.wikipedia.org/wiki/Orion_(spacecraft)

Edited October 29, 2015 by fredinno

[Firwen]

Capsules are also lifting bodies, they just don't need to carry all that stuff to space and back

Capsules, excepted for the Apollo one, has as much lift and manoeuvrability that a random stone thrown from space.

It has winglets, control surfaces, landing gear, tyres, brakes, doors, hydraulic lines, reservoirs, and pumps. It also has heavy heatshield material that covers a much wider area and which is exposed to MMOD damage throughout the mission.

The DMC shield is an ablative shield of the same kind of the ones used by the capsule and that has been used by the European IXV for demonstration, nothing new nor risky there.

All the others are all well-proved technology that has been around in the aerospace industry for 20 years.

The entire DMC concept is just to rely on "cheap" and proved technology: proved aerodynamics from HL-10/HL-20, simple/safe hybrid propulsion using nitrous oxide, ablative shield, composite structure made by Lockeed, RCS without hydrazine, simple landing gear with skies, etc, etc.

The main drawback of it would be its weight (11T) ....and even this seems rather reasonable compared to Progress/Soyouz (7-8T) or CST-100 (10-13T).

I have the impression that people hates the Dream Chaser just to hate the Dream Chaser. Mainly because they see the failure of the Shuttle by looking into it.

Edited October 29, 2015 by Firwen

[Alias72]

I have the impression that people hates the Dream Chaser just to hate the Dream Chaser. Mainly because they see the failure of the Shuttle by looking into it.

There may be a little more to it. Perhaps people simply trust ballistics more then pilots? after all who wants to see space jockeys joy riding over Nevada at mach 8!

[Hcube]

Capsules, excepted for the Apollo one, has as much lift and manoeuvrability that a random stone thrown from space.

This is so very completely wrong and absurd. I suggest that you look up a thing called "soyuz"... There are quite a few videos about soyuz's reentry on esa's channel that'll show you the difference between a rock and a high tech space capsule

I don't like the dreamchaser either because it just has so many incovenients that capsules don't have, and yes, i see the shuttle failure into it. It seems to bring the same avantages but with more drawbacks...

What avantages does it have over a capsule except cross-range, low-G re-entry and looks ?

Reusability ? Come on, it's launched with an expendable rocket...

I see many drawbacks however : can only land on a runway, lots of gear (->mass) plus a safety chute anyway!, added complexity->more failure points...

[Alias72]

Has SpaceX won the contract yet?

[Kryten]

simple/safe hybrid propulsion using nitrous oxide,

Hybrids are simple? Since when, exactly? VG have only just hit upon a design for their RM2 they think might be able to actually work, and they've been working on it for a decade. They even managed to kill a couple of people in a cold-flow test due to spontaneous decomposition of your 'safe' nitrous oxide.

[Mitchz95]

Has SpaceX won the contract yet?

Nope, the decision is made on November 5.

[Rune]

DreamChaser is a lifting body capsule that launches on top of a freaking disposable Atlas V. In fact, it has the disadvantages of the Shuttle with much less reusability.

It does much better in the safety department, and actually doesn't try to mix cargo and crew in the same flight. So it does have a few points over the STS, in my book. Not to mention Atlas V is a much better rocket IMO than the shuttle stack: similar payload, a fraction of the cost.

- - - Updated - - -

Capsules, excepted for the Apollo one, has as much lift and manoeuvrability that a random stone thrown from space.

Interesting then that when Soyuz makes an unguided reentry, the G's almost double and the landing ellipse grows much wider. ALL capsules employ a lifting reentry, except in emergency conditions.

A lifting body is just a trade, between ballistic coefficient and aeroshell mass. Heatshield mass doesn't change much, since the higher reentry of a lifting body with more surface implies lower peak temperatures... for a longer time.

All in all, about the only advantage is lower G's during reentry, at the cost of a worse mass fraction. For fragile, light cargo like tourists it might make sense.

- - - Updated - - -

Hybrids are simple? Since when, exactly? VG have only just hit upon a design for their RM2 they think might be able to actually work, and they've been working on it for a decade. They even managed to kill a couple of people in a cold-flow test due to spontaneous decomposition of your 'safe' nitrous oxide.

Since they only have one pump system for the oxidizer, which I guess means since they were invented. By definition they are almost half the complexity of a liquid fuel engine. Simplicty has nothing to do with safety... not that they are particularly unsafe. ALL rockets are very capable of killing people if you screw up, going to space just requires dangerous energy densities.

Rune. Then again, I doubt it'll ever fly.

[Kryten]

Since they only have one pump system for the oxidizer, which I guess means since they were invented. By definition they are almost half the complexity of a liquid fuel engine. Simplicty has nothing to do with safety... not that they are particularly unsafe. ALL rockets are very capable of killing people if you screw up, going to space just requires dangerous energy densities.

Mechanically simple maybe, in theory. But if you look at VG's hybrid effort, which is the commercial operation that's been working with hybrids at that scale, they now have;

-a separate pressurant tank in the nose, rather than using the NoX, due to it's unpredictable behaviour under rapidly changing pressures

-another tank in one wing root for methane, which they need to even-out instabilities at the start of the burn and prevent hard starts

-yet another tank in the wing root for helium, to damp down combustion instabilities at the end of the burn

and all this still doesn't get them their target performance.

[Rune]

Mechanically simple maybe, in theory. But if you look at VG's hybrid effort, which is the commercial operation that's been working with hybrids at that scale, they now have;

-a separate pressurant tank in the nose, rather than using the NoX, due to it's unpredictable behaviour under rapidly changing pressures

-another tank in one wing root for methane, which they need to even-out instabilities at the start of the burn and prevent hard starts

-yet another tank in the wing root for helium, to damp down combustion instabilities at the end of the burn

and all this still doesn't get them their target performance.

You focus on one company, and generalize for all hybrid rockets. Yet hundreds of rocket hobbyists have done hybrid rockets, and only a scant few have tackled pressure-fed bipropellants, much less pump-fed ones. There, a counter-example. Yup, VG screwed the development of their engine, big time. I'm sure it can be done better. But pump-fed bipropellants also have a myriad of subsystems and fluid loops... and their fair share of development failures when scaling up.

Rune. F-1 combustion instability, anyone?

[Kryten]

You focus on one company, and generalize for all hybrid rockets.

You realise we're talking about the same 'one company', yes? SNC was VG's subcontractor until not too long ago, these are their problems. And their problems were all in the scaling up, so hobbyists don't make much difference here. When they'd just finished the SS1 program they were talking about a common booster for DC and an orbital LV called Streaker with 6*SS1 thrust within a few years; now they're a decade later and they've failed to produce a motor with double the thrust.

[Rune]

You realise we're talking about the same 'one company', yes? SNC was VG's subcontractor until not too long ago, these are their problems. And their problems were all in the scaling up, so hobbyists don't make much difference here. When they'd just finished the SS1 program they were talking about a common booster for DC and an orbital LV called Streaker with 6*SS1 thrust within a few years; now they're a decade later and they've failed to produce a motor with double the thrust.

No we are not. I am refuting your comment about hybrid engines, and you keep bringing up VG's specific hybrid engine development history.

You said:

Hybrids are simple? Since when, exactly? VG have only just hit upon a design for their RM2 they think might be able to actually work, and they've been working on it for a decade. They even managed to kill a couple of people in a cold-flow test due to spontaneous decomposition of your 'safe' nitrous oxide.

And I replied:

Since they only have one pump system for the oxidizer, which I guess means since they were invented. By definition they are almost half the complexity of a liquid fuel engine. Simplicty has nothing to do with safety... not that they are particularly unsafe. ALL rockets are very capable of killing people if you screw up, going to space just requires dangerous energy densities.

I stand by my reply: "Hybrids" are simpler than bipropellant rockets.

Solids are simpler still. Doesn't make them safe, or reliable. That's the engineer's job. For example, the Pegaus rocket had an awesome track record with a single rocket failure in more than 40 launches, while the N-1 was a nightmare concerning reliability. OTOH, the Agena solid rocket failed two out of seven launches, while Soyuz has racked up some amazing reliability numbers, and the Saturn V or the Atlas V have managed a perfect record.

Edit: in any case, we are OT as hell. But for the sake of explaining myself a bit further, I don't really like hybrids much. They seem like a rather limited technology, with little prospect for reusabilty in the long run. An ugly compromise between solid and liquid that only offers limited Isp increase and the ability of shutting down. Still massively better than a solid booster for a manned rocket, tough.

Rune. A single data point does not a trend make.

Edited October 30, 2015 by Rune

[fredinno]

Edit: in any case, we are OT as hell. But for the sake of explaining myself a bit further, I don't really like hybrids much. They seem like a rather limited technology, with little prospect for reusabilty in the long run. An ugly compromise between solid and liquid that only offers limited Isp increase and the ability of shutting down.

Lunar Al Lox ISRU says otherwise.

[Rune]

Lunar Al Lox ISRU says otherwise.

Because running and engine on what is, basically, thermite, sounds like an easy proposition, compared with, say, filling tanks with LH2/LOX...

Two options there: you cast the fuel in-situ (requiring precision machining of the engine after each flight, basically rebuilding it), or you actually try to use aluminium powder as a fluid (which is totally not guaranteed to create hot spots that burn through the combustion chamber, or combustion instabilities).

Rune. There are reasons it hasn't been studied much.

[Rakaydos]

Two options there: you cast the fuel in-situ (requiring precision machining of the engine after each flight, basically rebuilding it), or you actually try to use aluminium powder as a fluid (which is totally not guaranteed to create hot spots that burn through the combustion chamber, or combustion instabilities).

Rune. There are reasons it hasn't been studied much.

The first option doesnt actually sound that bad, if the machining is done at a permanant site and not required to be produced onboard the rocket. A Lunar mining base that machnes alunimum "fuel grains" for hybrid landers to shuttle resources into orbit?

[Streetwind]

Here's an interesting rumor on this topic:

[Alias72]

Everyone knows SpaceX will get one of the spots.

Most people here have concluded that the competition will be between Boeing and Orb.

The winner will be whoever has the nicest price point (as I believe that was the main issue with Orb in the last contract.)

So the question is whether Boeing's new design can out-compete Orbitals.

[Kryten]

Everyone knows SpaceX will get one of the spots.

Based on what, exactly?

[fredinno]

Based on what, exactly?

Capable of Downmass and Unpressurised cargo, which are required for ISS, and the only other CRS vehicle that can do that is Dream Chaser.

[Kryten]

CST-100 has unpressurised cargo as a mission module, next-gen Cygnus could do the same. NASA are trying to reduce the number of cargo flights for easier fitting into ISS manifest, Dragon has the lowest upmass figures of any of the vehicles. If you look at the actual payload carried on most flights, it only just reaches the requirements for CRS-2.

[Alias72]

Based on what, exactly?

Based on their cost versus performance as well as their good showing during CRS-1.

Also there are political currents in the US pushing for a new competitor in the space industry. SpaceX has revived american commercial spaceflight and many politicians wish to be associated with that.

Finally. Aerospace is conservative. SpaceX has been partially accepted into the "in" club.

[Nibb31]

Yes, for CRS-2, I think that SpaceX is a pretty sure win: they have past performance, CBM berthing, downmass, unpressurized cargo, and all developed and flight-ready.

None of the other contenders can match the capabilities of Cargo Dragon without some development work, and therefore risk. I think Cygnus is ahead of CST-100.

[Firwen]

None of the other contenders can match the capabilities of Cargo Dragon without some development work, and therefore risk. I think Cygnus is ahead of CST-100.

Has Orbital Sciences ever talk about downmass or reentry for Cygnus ?

Up to my knowledge, nor Cygnus nor Cygnus enhanced have been design for it. They are built around a Thales Alenia aerospace pressurized module, single-block and without heat-shield or re-entry capacity.

If downmass and re-entry are a main requirement for CRS-2, that's imply a major redesign of their vehicle.

The only other two spacecraft being already designed for re-entry being the Dream Chaser and CST-100.

Edited November 2, 2015 by Firwen