Orion program delayed 2 years

[fredinno]

Ok, before start, I guess you are not being complete honest here, some of the arguments that often are used to criticize designs as (complexity and extra components, lower safety, etc) now for the orion case it seems they are a good choice.. how is not that being biased? XD

yeah it seems that I misunderstand one of my sources, sorry. (I will edit my previous post)

Is 6.8T which only a 30% of that is proppelent. The orion capsule mass is 9T, this mean that the LES system needs a the 75% of the capsule mass, and we need to add 400kg for the reserve parachutes (which dragonv2 does not need), so we have almost 80%.

In the DragonV2 case, the proppelent + 4x2 engines + hellium tanks (I have to estimate the superdraco 4x2 mass from the picture) 1400kg + 4x100kg + 100kg = 2T aprox, which is less than 40% of the dragon capsule. (dragon v2 dry mass is 4.2 T, this include the tanks and engine mass)

Orion LES system=80% of the capsule mass.

Dragon LES system= 40% of the capsule mass. (reusable and throttleable)

If the Orion eject the LES system before the burn to orbit ends, then it risk to have a failure after that event.

Why you will connect the fuel tank in the top? Why it can not be in the trunk? How do you think the orion makes all connections (less fuel) to the service module?

https://upload.wikimedia.org/wikipedia/commons/thumb/a/af/Orion_Service_Module_elements_2015.jpg/800px-Orion_Service_Module_elements_2015.jpg

Of course the Dragon should be higly modify as a dragonV3, but you can have 4 connections for each x2 superdraco engines by the side.

We are not comparing functions and roles of each capsule, just the benefics of each LES system.

Is less than that if you figure out the service module proppelant mass and all the other aspects.

If you accept one step further in development, it will be possible to have a methane/ox fuel for RSC and main thrusters reaching +350 isp.

As this study with test show.

About my draco dv estimation of 650, I forget to have the 10^o tilt into account, is closely to 600m/s

again this mean extra risk, also as I prove, the mass for this LES system is much higher in mass % than the Dragon LES.

why is hypothetical? the draco RSC thruster was scale up to become a superdraco thruster, of course is a complete different design, but you can always scale up things with develpment. And we are not talking about a huge difference between Dragon requirements and Orion requirements.

Yes, with development. That worked very well for SpaceshipTwo so far (I know it's different, but I just wanted to use it for comparison.) Not that SpaceShipOne and Two had much different requirements.

On the other hand, the mass of the Orion LES includes the canards, and control surface mass of the LES, required, because it would be impossible to control ascent otherwise. No idea how Dragon V2s move the capsule horizontally, though. There is little information on it, in comparision to Orion's.

The capsule would need a redesign, even if the SM was placed in the trunk- I just said the SM would be placed in front, in order to have to have the system requiring the least modifications. It's more difficult to place fuel lines through heat shields (I think). You can place it in the trunk too.

Dragon V2 needs reserve chutes for landing too, Launch Abort uses up the fuel for propulsive landings.

- - - Updated - - -

AJ10 has enough thrust to get Orion away after LAS is jettisoned.

Niether IDS or Dragon's trunk umbilical can route fuel to the capsule - you might as well just put a little rocket stage in the trunk!

Cryogenic non-hypergolic RCS is a very bad idea!

Why is cryogen RCS a bad idea? Just wondering.

[StrandedonEarth]

Cryogenic fuels boil off over time, although methane wouldn't be as bad as hydrogen. Hypergolics are used in RCS for simplicity; very little can go wrong and no igniter is necessary. That's why the LEM used pressure-fed hypergolics; it had to work and there are very few moving parts. Just let the fuel flow and you have ignition

[Budgie]

Cryogenic fuels boil off over time, although methane wouldn't be as bad as hydrogen. Hypergolics are used in RCS for simplicity; very little can go wrong and no igniter is necessary. That's why the LEM used pressure-fed hypergolics; it had to work and there are very few moving parts. Just let the fuel flow and you have ignition

I'd go as far as to say hypergolic or cold gas RCS is almost a requirement. For a thruster that ignites so many times in any given mission, unlike the long burns of the main propulsion system, you'd want it to ignite or provide thrust as reliably as possible. With hypergols and cold gas, there's thrust every time

[fredinno]

I'd go as far as to say hypergolic or cold gas RCS is almost a requirement. For a thruster that ignites so many times in any given mission, unlike the long burns of the main propulsion system, you'd want it to ignite or provide thrust as reliably as possible. With hypergols and cold gas, there's thrust every time

How about using hot air as RCS?

You know, THAT hot air, the stuff that isbever in short supply.

[Nibb31]

I dont understand, can you elaborate please?

I am comparing "abort launch systems", not capsules.

We've already said that that is just as stupid as comparing the wings of a 787 with the wings of a Cessna, or the engine of a motorbike with the engine of a tank. They all serve the same function, but the vehicles themselves have different missions and requirements.

Dragon is designed for regular trips to LEO. It makes sense to make it reusable, which means that it makes sense to carry the engines back as long as the mass penalty allows payload requirements to work.

Orion is designed for exploration missions at a rate of once a year. At that flight rate, it doesn't need to be reusable. Since the whole system is expendable, it makes sense to jettison as much as you can along the way in order to minimize mass before each burn.

And even if the orion system has a bit more power, its because the capsule is bigger (and maybe the SLS produce more G, not sure).

If the orion would have its engines included, then it could be used to land in the moon or mars, and the service module would be just an external tank. In my opinion the dragon system does not have any cons with respect the orion system.

I think you might be insinuating that you could use Dragon to land on the Moon or Mars, which simply isn't possible without, again, heavily redesigning it. It doesn't have enough dV to land on the Moon, and it could only do a 1-way landing on Mars (with an expendable upper stage to do the deorbit burn), which is pointless.

If you add a tank, you make it heavier, so you need more thrust, which means more weight, which means more engines and more tanks, etc... The typical new KSP player's mistake !

If Dragon carried the same equipment and the same internal volume as Orion, it would be the same weight as Orion, so it would need the same sized LES as Orion. The only difference would be that Orion dumps its LES when it is no longer needed while Dragon retains that mass for the whole mission.

Again, for Dragon's LEO taxi mission, that's perfectly acceptable. If you are going to the Moon and back every year or two, then bringing several tons of landing gear for the last seconds of the mission is either wasted payload or lower dV, for no real benefit.

It would not need those extra parachutes and that heavy faring, its volume would be a bit higher to keep the aerodynamic coefficient.

Crew Dragon has parachutes for redundancy. All the Commercial Crew missions will be parachute landings because powered landing is unprovene. When they do start powered landings they won't be removing the parachutes until they build confidence in the system, which won't happen before the end of the CC program.

Edited September 22, 2015 by Nibb31

[AngelLestat]

AJ10 has enough thrust to get Orion away after LAS is jettisoned.

Yeah I already correct my post. Thanks.

Niether IDS or Dragon's trunk umbilical can route fuel to the capsule - you might as well just put a little rocket stage in the trunk!

Well maybe you dint read me here, but I was super clear... IT NEEDS DEVELOPMENT.

Also I am not talking about Dragon, I am saying that Orion could have the Dragon LES with all its benefics.

An extra engine in the trunk will add mass and is not great for landing if it is so close to the floor. Knowing how damaging can be moon dust or mars dust.

Cryogenic non-hypergolic RCS is a very bad idea!

Said who?

https://en.wikipedia.org/wiki/Project_Morpheus

Paper 1, Paper 2

There is a problem with hypergolic fuel, it has low ISP and this:

It needs heavy devices and containers to reduce the risk, it can be a problem if you land and the the proppelent enter in contact with water.

You can not use ISRU.

On the other hand, the mass of the Orion LES includes the canards, and control surface mass of the LES, required, because it would be impossible to control ascent otherwise. No idea how Dragon V2s move the capsule horizontally, though. There is little information on it, in comparision to Orion's.

Dragon LES system does not need all that, it control all varying each engine thrust independently. The tower escape system will remain obsolete once dragon v2 get more tests and prove without question the design.

It's more difficult to place fuel lines through heat shields (I think). You can place it in the trunk too.

Is through the sides as the Orion connections.

Dragon V2 needs reserve chutes for landing too, Launch Abort uses up the fuel for propulsive landings.

No, for example Orion has its main parachute system and one of reserve.

Dragon v2 as main landing option is using the superdracos, and then it has parachutes as reserve. So it does not need extra parachutes to get the same redundancy. That is the mass I discount from the dragon LES, because yeah, you are adding weight with the proppelent and engines, but you dont need the extra reserve of parachutes.

We've already said that that is just as stupid as comparing the wings of a 787 with the wings of a Cessna, or the engine of a motorbike with the engine of a tank. They all serve the same function, but the vehicles themselves have different missions and requirements.

Why is like comparing the wing of a 787 which speed and weight is hundreds of time more than a cessna?

The capsules in size and mass are very similar, the speed in atmosphere is also similar. Besides we are not talking of removing the same draco thruster and installing in the orion, we are talking about the system!! The soyuz use the same system but with different scale..

I know you dont want to compare these two systems because is clear that the tower system is obsolete. It has no pros vs the other.

A picture to see that the orion is not 50 times bigger.

Dragon is designed for regular trips to LEO. It makes sense to make it reusable, which means that it makes sense to carry the engines back as long as the mass penalty allows payload requirements to work.

This argument makes sense.. but still.. I dont really see the benefic more than (a system already prove it), the tower system needs more cordination between procedures on control and detach parts. And for me even if you would not use it often, being able to reduce cost and risk (by proven capsule) in reusability it worth it.

Orion is designed for exploration missions at a rate of once a year. At that flight rate, it doesn't need to be reusable. Since the whole system is expendable, it makes sense to jettison as much as you can along the way in order to minimize mass before each burn.

But the deltaV you eat in the launch is still considerable with the extra mass of the system, it make the ejection in the third stage.

https://youtu.be/f6Eaj-Vg9Ns?t=1m24s

Then take a look to the numbers of orion and its low deltaV with a high amount of proppelent.

https://en.wikipedia.org/wiki/Orion_(spacecraft)

Its clear that it has some other penalties in mass that it would not have with the dragon system, plus an extra stage.

I think you might be insinuating that you could use Dragon to land on the Moon or Mars, which simply isn't possible without, again, heavily redesigning it. It doesn't have enough dV to land on the Moon, and it could only do a 1-way landing on Mars (with an expendable upper stage to do the deorbit burn), which is pointless.

No, as I explain, I am saying that the orion could have that benefic with the dragon system if some rescue mission will require it.

If you add a tank, you make it heavier, so you need more thrust, which means more weight, which means more engines and more tanks, etc... The typical new KSP player's mistake !

Easy, you dont detach the trunk, but you detach the tank in case you need to use LES.

About to land in the moon or mars or even in earth (which is not necesary because you already have an internal tank in the capsule), the draco engines has power to spare...

Crew Dragon has parachutes for redundancy. All the Commercial Crew missions will be parachute landings because powered landing is unprovene. When they do start powered landings they won't be removing the parachutes until they build confidence in the system, which won't happen before the end of the CC program.

Not sure if I understand you, first I dont care in what step of development they are right now. What I review is the final system they try to accomplish..

The final system will have superdracos as main system, and parachutes as emergency. But without extra spare of parachutes.

If it would be my choice, in a third version, I would not use the parachutes and I will remplace them with heli-rotor blades.

Edited September 23, 2015 by AngelLestat

[Motokid600]

If it would be my choice, in a third version, I would not use the parachutes and I will remplace them with heli-rotor blades.

Motorized helicopter blades? How would you counter rotate? Rcs? I think that might be a bit extreme. Contra rotating blades? No way in hell that'd ever be lighter then parachutes.

[MajorLeaugeRocketScience]

Actualy, it's sls that's behind, not orion

[sojourner]

Guys, just give it up. He just doesn't understand how things work. He's too busy asking "why don't we just do this?" without thinking about "why can't it be done?".

[AngelLestat]

Motorized helicopter blades? How would you counter rotate? Rcs? I think that might be a bit extreme. Contra rotating blades? No way in hell that'd ever be lighter then parachutes.

In this case you just need to counter the friction of your rotor (an smal fin is enoght). In the helicopter case you need to counter the torque produced by the engine which is much much higher.

The blades could be folded or expand (one inside the other) to match the capsule side. You can direct the glide and land super soft as any helicopter doing autorotation

http://www.nasa.gov/centers/kennedy/news/rotocapsule.html

Edited September 23, 2015 by AngelLestat

[Motokid600]

Interesting. But even with that id still want a parachute incase theres a deployment issue.

[Kibble]

There is a problem with hypergolic fuel, it has low ISP

Actually good hypergolic rocket engines have ISP as high as 320 s.

You can not use ISRU.

You can. With access to water and ammonia ice you can make hydrazine and nitrogen tetroxide.

The tower escape system will remain obsolete once dragon v2 get more tests and prove without question the design.

Why? Escape towers work! They are simple, effective, and not too heavy. Besides a piloted rocket just don't look right without it :3

[Nibb31]

Also I am not talking about Dragon, I am saying that Orion could have the Dragon LES with all its benefics.

No it wouldn't, because if it did, the capsule would have to be heavier, which means that vehicle would have less dV or would need a larger service module, which reduce the dV of the EUS, etc...

And there are no benefits (it's benefits in English) for Orion to carry its LES all the way to the Moon or Mars.

The tower escape system will remain obsolete once dragon v2 get more tests and prove without question the design.

No it won't. It depends on the mission

No, for example Orion has its main parachute system and one of reserve.

Dragon v2 as main landing option is using the superdracos, and then it has parachutes as reserve. So it does not need extra parachutes to get the same redundancy. That is the mass I discount from the dragon LES, because yeah, you are adding weight with the proppelent and engines, but you dont need the extra reserve of parachutes.

Orion has three parachutes, but can land safely on two. There is no reserve system.

Dragon has exactly the same arrangement.

Why is like comparing the wing of a 787 which speed and weight is hundreds of time more than a cessna?

The capsules in size and mass are very similar, the speed in atmosphere is also similar.

I wasn't talking about mass, I was talking about mission. I don't really know how to get this through your thick skull. Orion and Dragon are different vehicles with different missions. Is a supertanker superior to an aircraft carrier? Both have different missions, therefore their systems are engineered for different requirements.

Dragon and CST are taxis. Their job is to commute between the ground and LEO. Launch and reentry are the main parts of that mission. They are optimized for routine operation and low cost.

Orion is an exploration vehicle. Launch and reentry are only first and last minutes of the mission. It is optimized for its versatility and ruggedness and cost is less of a factor.

You really aren't getting this point. There must be something that isn't connected in your brain or something. At this point, I'm really going to give up because I can't figure out how to say it any other way.

Besides we are not talking of removing the same draco thruster and installing in the orion, we are talking about the system!! The soyuz use the same system but with different scale..

Nobody is seriously suggesting putting draco thrusters and tanks on the Orion capsule. What would be the point? Adding stuff makes it heavier. You would need heavier and bigger parachutes, a heavier and larger SM, etc... The LES works as required and is jettisoned when it's no longer needed so that it doesn't add extra mass for the rest of the mission.

[AngelLestat]

Actually good hypergolic rocket engines have ISP as high as 320 s.

The ones used in dragon and many other spacecrafts has 240s, maybe those with 320s has more drawbacks.

You can. With access to water and ammonia ice you can make hydrazine and nitrogen tetroxide.

haha, ok then we should take Walter White for the mission.

To set a full chemical laboratory "of danger substances" in mars.

No it wouldn't, because if it did, the capsule would have to be heavier, which means that vehicle would have less dV or would need a larger service module, which reduce the dV of the EUS, etc...

ok, lets settle this once for all.

The only hypothetic drawback that the Dragon LES may have, is less deltaV for the whole missions right?

Then lets prove that, lets see how much deltaV we lose.. I dont know how to calculate with accuracy deltaV inside the atmosphere, so we can added to the total deltaV needed for a mars mission (the worst case scenerario for the DragonLes in term of deltav)

We know that the tower system requires almost 80% of the capsule mass, and the other system requires less than 40%.

I suppose than when SLS change to its third stage, it already consume a 60% of the total delvaV including the service module. This is the moment the first tower-LES system eject.

Tower-LES: carry a 80% from the capsule mass over the 60% from the total DeltaV.

Draco-LES: carry a 40% from the capsule mass over the 100% from the total DeltaV. But!!! the deltaV this system provide is still there to be used, it was not ejected as the other system (big difference!).

So, the exact math will take me much more time to do it, but we may have a good idea that there is not real deltaV difference, so the only cons the Draco-LES system may had was denied.

And all mission provide extra deltaV as emergency, in this case if you use the Draco-LES deltaV, you still can land with parachutes with the same redundancy. If you dont need to use that emergency deltaV, then you can land with propulsion and recover the capsule.

And there are no benefits (it's benefits in English) for Orion to carry its LES all the way to the Moon or Mars.

Why not?? Is extra deltaV that you can use in case of emergency, you still have the parachutes to land.

Orion has three parachutes, but can land safely on two. There is no reserve system.

Dragon has exactly the same arrangement.

Let me elaborate:

Orion the same than Dragon (now) has five parachutes. Three are main parachutes and two are drogue parachutes. They needs only two main parachutes and one drogue. The extra two provide a backup in case one of the primary parachutes fails.

Dragon has that because it needs its certification to land with only parachutes as NASA wants for the first missions.

But when it gets its certification for propulsive landing, it may decrease the side of the five parachutes or just keep 2 main and 1 drogue.

In case it doesn´t, then the capsule will have even more redundancy than Orion or any other capsule.

Dragon and CST are taxis. Their job is to commute between the ground and LEO. Launch and reentry are the main parts of that mission. They are optimized for routine operation and low cost.

Orion is an exploration vehicle. Launch and reentry are only first and last minutes of the mission. It is optimized for its versatility and ruggedness and cost is less of a factor.

It seems that you never had to took a decision in your life.. is all about measuring pros and cons.

Yeah they have different missions.. lets focus just in the ORION mission!

What it would be orion´s pros and cons using a similar version of the superdracos instead the tower?

Draco-LES for Orion

Pros:

1) If the extra deltaV is not needed, it increase the redundancy for landing.

2) if the extra deltaV is not needed, it can be reusable which may reduce the cost and provide extra safety because it was already test it.

3) Less moving parts and activation systems in abort scenarios.

Tower-LES for Orion

Pros:

1) the technology is much more mature.

I simplify equal cons and pros in both.

You really aren't getting this point. There must be something that isn't connected in your brain or something. At this point, I'm really going to give up because I can't figure out how to say it any other way.

oh.. more insulting.. but I already prove it. you lose.

[Red Iron Crown]

Here's the point you're missing:

The Dragon LES system for a BEO mission is close to dead weight. BEO missions need more efficient propulsion than atmo-optimized engines can provide, every gram of that sort of system is better replaced with more propellant for the vacuum propulsion system or omitted altogether. *That* is why Orion's LES system is better for BEO missions, it is jettisoned before the BEO part of the mission is started.

Dragon's system is good for the mission it is designed for, which is a different mission than Orion's.

The reason Dragon's hypergolic Isp is so low is not because of the propellant choice, but because it's optimized for atmo work. A specialized vacuum engine using the same propellants would have much better vacuum Isp (and much, much lower atmo Isp, which is why it would be unsuitable for LES/Earth landing purposes).

[G'th]

^ Yeah, but your facts are wrong, and heres why...

[Mitchz95]

*munches popcorn*

[AngelLestat]

Here's the point you're missing:

The Dragon LES system for a BEO mission is close to dead weight. BEO missions need more efficient propulsion than atmo-optimized engines can provide, every gram of that sort of system is better replaced with more propellant for the vacuum propulsion system or omitted altogether. *That* is why Orion's LES system is better for BEO missions, it is jettisoned before the BEO part of the mission is started.

Dragon's system is good for the mission it is designed for, which is a different mission than Orion's.

The reason Dragon's hypergolic Isp is so low is not because of the propellant choice, but because it's optimized for atmo work. A specialized vacuum engine using the same propellants would have much better vacuum Isp (and much, much lower atmo Isp, which is why it would be unsuitable for LES/Earth landing purposes).

^ Yeah' date=' but your facts are wrong, and heres why...[/quote']

I just answer this in the previous post..

It seems nobody reads the answers to other users. Here it is:

The only hypothetic drawback that the Dragon LES may have, is less deltaV for the whole missions right?

Then lets prove that, lets see how much deltaV we lose.. I dont know how to calculate with accuracy deltaV inside the atmosphere, so we can added to the total deltaV needed for a mars mission (the worst case scenerario for the DragonLes in term of deltav)

We know that the tower system requires almost 80% of the capsule mass, and the other system requires less than 40%.

I suppose than when SLS change to its third stage, it already consume a 60% of the total delvaV including the service module. This is the moment the first tower-LES system eject.

Tower-LES: carry a 80% from the capsule mass over the 60% from the total DeltaV.

Draco-LES: carry a 40% from the capsule mass over the 100% from the total DeltaV. But!!! the deltaV this system provide is still there to be used, it was not ejected as the other system (big difference!).

So, the exact math will take me much more time to do it, but we may have a good idea that there is not real deltaV difference, so the only cons the Draco-LES system may had was denied.

And all mission provide extra deltaV as emergency, in this case if you use the Draco-LES deltaV, you still can land with parachutes with the same redundancy. If you dont need to use that emergency deltaV, then you can land with propulsion and recover the capsule.

PD: not sure what excuses will come out next. But I can not explain it better than this. Is clear and logic that you dont lose deltaV with this system in BEO.

[sojourner]

Have you ever even played Kerbal Space Program? How can you play the game and not learn how important it is to drop dead weight for BEO missions?

As an exercise, why don't you try building a mission to Duna and experiment with taking a capsule with LES engines and one without. See how much more D/V it takes you. Then try, just try, to imagine how much that would translate into additional costs in the real world.

Oh, and here's a clue: if multiple people are telling you you're wrong, guess what? You're probably wrong.

Edited September 23, 2015 by sojourner

[Red Iron Crown]

Show your math if you are going to call something "proven".

Hint: you are only considering the mass of the capsule itself for the BEO mission. You must also consider the rest of the service module that will be used. For clarity: We are talking about the delta V of the vessel in orbit, not the lifter.

[Motokid600]

@AngelLestat - Just to clarify. All this because your against the use of older, proven technology/methods?

[fredinno]

Have you ever even played Kerbal Space Program? How can you play the game and not learn how important it is to drop dead weight for BEO missions?

As an exercise, why don't you try building a mission to Duna and experiment with taking a capsule with LES engines and one without. See how much more D/V it takes you. Then try, just try, to imagine how much that would translate into additional costs in the real world.

Oh, and here's a clue: if multiple people are telling you you're wrong, guess what? You're probably wrong.

Not delta-v, fuel. And KSP is not real world- propellant fractions are higher, for example.

[EuSouONumero345]

Well, we did have help from some very smart Germans.

Also, not us. Ancestors. People that wanted to do it.

Also, the first man was a Russian by the name of Gagarin, Yuri Gagarin.

I think he meant the human race.

[sojourner]

Not delta-v, fuel. And KSP is not real world- propellant fractions are higher, for example.

D/V is a better measure than fuel, even in KSP. And no, KSP is not the real world, I never said it was. But it does give an excellent idea of the math involved. Something AngelLestat seems to have problems with.

[Bill Phil]

D/V is a better measure than fuel, even in KSP. And no, KSP is not the real world, I never said it was. But it does give an excellent idea of the math involved. Something AngelLestat seems to have problems with.

Actually, to compare two systems that do the same thing, Delta V is the same for both. The mass ratio is different, though. And the mass of the propellant.