Apollo 8, redux

elderflower · 2017-03-02 03:38:02

Catalytic breakdown of high test peroxide gives a high temperature oxygen/water vapour stream in which almost any combustible fuel will burn without separate igniters. That is to say it is hypergolic.
You need to add stabilisers to HTP to restrict unscheduled breakdown. If manufactured on Mars, the stabilisers will have to be brought from earth.
Freezing point depends on water content, but is sub zero. A freezing point of -15 results from a concentration of about 85% peroxide. This has been used with jet fuel for rocketry, with which it is hypergolic.
Great care in design and material selection is needed to restrict the chance of the stuff going off by itself. This problem gets worse as the water content is reduced, but on the other hand the Isp goes up. In service as torpedo fuel it has sunk a couple of submarines, although I am not sure what concentration they used.

Tom Kalbfus · 2017-03-02 07:33:59

I see, Mars does not have the necessary elements to make them.

elderflower · 2017-03-02 11:15:34

Mars does have what you need for peroxide, but not for the stabilisers that are used on earth. They are used at up to 1% or so in the water /peroxide mix. You have to import a miniaturised chemical plant to make the peroxide, but that is true for all in situ manufacture of fuels and oxidisers.
For fuel I would favour methanol or maybe propane. Methanol is easy to make and store and Mars has the ingredients, although Isp would be higher with propane or butane. Higher still with propadiene/methyl acetylene.
Since high test peroxide is effective as a mono propellant it is convenient for attitude control thrusters.

GW Johnson · 2017-03-02 11:23:22

Two issues I know something about and should comment on.

(1) reentry vehicles fashioned out of a Cygnus and some sort of inflatable or deployable heat shield: these will need some sort of attitude thrusters to maintain precision trajectory that lands close to whatever recovery ship (or ships) there is. Warheads are sort of naturally stable due to shape and cg location, capsules much less so. If the capsule cg is far enough behind the heat shield, natural stability gets iffy. Attitude thrusters are required to "fix" that problem, which is separate from sliding ballast for hypersonic lift.

Dynamically, ballast is far too slow an effect to provide attitude control in vehicles of practical size. What it does is provide an offset in attitude about which the actual attitude control must act very quickly, from a dynamical standpoint. The bigger the vehicle, the tougher this is, as moments of inertia vary as dimension squared.

If the heat shield is structurally compliant (meaning its shape responds to applied airloads), stability is worsened further, because shape and pressure distribution is no longer constant. Such a configuration will simply require attitude thrusters (as well as a back shell or ceramic blanket to protect the aluminum Cygnus from wake gas heating).

(2) I know there are some new non-toxic hypergolic thruster propellant combinations, but we have little actual experience with them yet. Once we do, they may (or may not) supplant the toxic but well-characterized NTO-MMH combination. That replacement depends upon identifying (and dealing with) all the little pitfalls and nuances that only experience uncovers.

The way around the toxicity problem is to vent the propellant residuals singly through the thrusters (so that combustion does not occur and thrust is not produced) after the chute deploys, but before capsule venting is opened. That's simple enough, and would have reduced-greatly (or even eliminated) the personnel hazards we encountered with Apollo and shuttle. Once we know enough about non-toxic propellants to actually replace the toxic ones, then this is no longer necessary.

As for hydrogen peroxide, what you have is a situation where stability/safety, hypergolic ignition characteristics, and propellant specific impulse characteristics are all functions of peroxide concentration (the lower the water the better the performance and ignition, but the worse the hazard). You don't achieve the published Isp numbers until you are above 90% concentration, although 80% ignites and burns with kerosene. It just does so at reduced performance.

I don't know much about any stabilizers except that they now really do exist, but without them, peroxide concentration needs to be under 50% for long term stability. Violate that, and sooner or later the tank spontaneously explodes, sometimes in just a day or so at 90%. With the stabilizers, the concentration limit that is safe for long term stability is higher (no, I don't know what it is), but it's got to be still well below "rocket grade" 90%, or we wouldn't be talking about trying to use it at 80%. Get your thermochem code out and watch Isp (c* really) fall as you dilute the mix with steam.

Before Spacex came to the old plant site at McGregor where I worked long ago, there was another rocket launch business there run by Andy Beal. His version was H2O2-kerosene. They kept peroxide on site watered down at 50%, and distilled it up to rocket grade 90% for use in firings. They did blow one tank up from inherent high-concentration instability. You get little warning: a sudden small rise in temperature and bubble formation right before the explosion seconds to minutes, not hours). Same thing used to happen in submarine torpedoes that used H2O2 with ethanol fuel. (Plus the sailors would steal the ethanol and drink it.)

GW

Last edited by GW Johnson (2017-03-02 11:40:56)

Oldfart1939 · 2017-03-02 13:28:21

For use in the real world--hydrogen peroxide is a no-go, and that's coming from a chemical professional with over 50 years in the Chemical industry! On paper, it looks great, but on paper it will remain. No serious chemist would ever suggest using the stuff. The Germans used it to power their Me 163 rocket fighters along with a hydrazine fuel. They blew up a lot of them while sitting on the ground, during takeoff, and from the residues during landings. I may be an idiot to be willing to ride in a rocket powered rocket, or airplane, but NOT if it has H2O2 in the system---anywhere!

kbd512 · 2017-03-02 13:33:55

elderflower,

We do not need to put chemical production plants on the moon or Mars to send exploration teams to those places. I proposed H2O2 as an oxidizer for use with HAN as a low toxicity storable bi-propellant alternative to N2O4/MMH. Frankly, I would just stick with N2O4/MMH since we already know how those propellants work and all the technology required to use them is available for purchase as I write this.

We already have rockets and propellants to solution propulsion problems associated with lunar missions. There is no need for another expensive rocket development scheme unless someone is intent on derailing lunar exploration missions. Anyone claiming LOX/LCH4 is required for a lunar mission is declaring a snow day, as Dr. Zubrin would say.

Did anyone learn anything from SLS and Orion? Does anyone else have any ideas about how we could go back to the moon without requirements to develop new rockets we don't have, new spacecraft we don't have, or new technologies we don't have?

Here's what we do have...

Lift Vehicles:
Atlas V
Falcon 9
Falcon Heavy (pictures were taken on the street of the distinctive side boosters leaving McGregor, TX about a month ago)

Propellants for upper stages, kick stages, and RCS:
LOX/LH2 - RL-10
LOX/RP1 - Falcon Upper Stage
N2O4/MMH - Variety of engines for RCS, but AJ-10-190 is the most well developed for kick stages

Capsules:
Dragon
Dragon V2
Soyuz

Cargo Modules:
Cygnus
MPLM

Power:
Ultra-Flex
Mega-Flex
ROSA
Lithium-ion batteries
Fuel cells
RTG's

GW Johnson · 2017-03-02 13:46:41

I'm not sure, but I believe the Germans used hydrogen peroxide catalyzed decomposition as the "catapult" force to sling both the ME-163 and the V-1 Buzz Bomb into the air. For the Me-163, it was straight up a tower as a launch rail. For the Buzz Bomb it was up a long gently-sloped launch rail. Some sort of free piston rig similar to that used in the steam catapults on aircraft carriers. I don't know what concentration they used. But it had to be well above 50%.

GW

SpaceNut · 2017-03-04 21:36:36

Nice list of hardware capability for use kbd512 but without some alterations we will not be doing much with it other than circling the moon on a free return path....We do have some other coming soon to the playing field and it is getting interesting to see if NASA can retain its lead with capability for space travel Robotically or with Human flight.

With a bright future with some of these others...

streambe_cb70c647-e242-30ef-9802-dedc748fa4e6-2116355148.jpeg

kbd512 · 2017-03-05 01:44:29

Apparently Blue Origin thinks they can teach people what they need to know to be an astronaut in a day. I almost fell out of my seat laughing.

Terraformer · 2017-03-05 08:36:03

If they're just a passenger, then it's not so far fetched. We don't even bother with training for aircraft passengers.

As regards regular Lunar missions, the delta-V for Earth orbit - Lunar orbit - Earth orbit is 5.4 km/s with aerocapture. A MethLOX vessel using Raptor engines could do that with a mass ratio of ~4.26 - a mass ratio of 5 would give it ~6 km/s delta-V. If we develop on-orbit refuelling, such a vessel would significantly lower the costs of each mission. Perhaps it could even be launched as a Falcon Heavy upper stage.

Oldfart1939 · 2017-03-05 10:14:50

All Blue Origin has currently flying is the suborbital New Shepard; they have a long way to go before they begin flying the New Glenn. I'm just guessing, but maybe a static test of components in a year, first test flight in maybe 2 years? First flight to orbit in 3? Man rated in 5? Pretty optimistic.

SpaceNut · 2017-03-05 20:40:48

The ULA is having this company create a replacement engine for the Atlas V RD180 so that they can also build up the new Vulcan rocket but like you was saying thats at least 5 years down the road for flying.

SpaceNut · 2017-03-05 21:01:51

Oldfart1939 wrote:

GW-
An interesting concept would require use of another component in the system: the Russian-built Proton M 3rd stage. Here are the details:
Type: Storable Propellant Stage
Inert Mass: 4,185 kg
Diameter: 4.14 meters
Length: 6.5 meters
Propellant: UDMH
Oxidizer: NTO
Fuel & Ox: 46,562 kg
Total thrust:613.8kN
Burn time: 238 seconds
Isp(vac): 325 seconds
My suggested model incorporates the Falcon 2 + Trunk, + dry Proton M 3rd stage to ~20,000kg, including upgraded onboard fuel for retro propulsive landing on Earth. I'm figuring on a delta V around 3.5 km/sec for the rocket equation. This gives a mass ratio of ~ 3.0.
If we configure the Dragon 2 for a crew of 4, with onboard supplies for food, an atmosphere purifier, no water recycling at 11,000 kg, adding tankage and additional fuel over and above the "normal" 1900 kg at 3,800 kg (total fuel = 5,700 kg), the empty mass of the Proton M 3rd stage at 4,185 kg, and a trunk with a motor at 1500 kg, we get a payload mass of 20,485 kg. Fully fueled, this results in a total "wet" rocket mass of 67,047 kg with a mass ratio of 3.27. This implies there will be fuel remaining after departure for insertion into Lunar orbit. The increased fuel for the Dragon capsule also implies sufficient fuel for de-orbit burn and adequate fuel for dry land propulsive landing.
This is not the calculation of a sophisticated aerospace engineer, just an amateur. Please make comments! This requires orbital assembly and 2 loads to LEO. The mass of the Proton M 3rd stage is well within the capability of the Falcon Heavy.

SpaceNut · 2017-03-05 21:03:43

SpaceNut wrote:

Now you all see why we are having trouble keeping topics organize with a scope of discusion an ther is so much out of the box comments.
The trouble with a progress stage is the coupling of them does not match up as the core of the falcon is 3.7 m in diameter which now means interstage coupling collars are need to make an off the shelf work at all.
The again it is just a small thing as even an extended stage from Space x would also need a interstage coupling collar to mate the stages together for such a flight to occur thou these would be simpler as they already make use of them. I am sure with modifications to those that we would have a better match up of the sections to build the lunar rockets components up at the ISS.
Space x can only move so fast with all the changes that are needed in order to progress what they have to being able to do the flyby and then to proceed to being able to create something to think about landing with.
If I were the other rocket launch companies out there I would be looking to build up from what they have a rocket capable of the same feat. This is what speers on competition as its availability to provide at a cost of affordability that we need.

SpaceNut · 2017-03-06 19:59:48

With GW's reverse engineering numbers we now know with confidence that we can do a flyby with a bit of safety with everything going just right all the way.

SpaceNut · 2017-04-30 14:26:23

It seems as SpaceX undecided on payload for first Falcon Heavy flight

The Falcon Heavy’s three kerosene-fueled boosters will generate more than 5.1 million pounds of thrust at sea level, and the rocket stages mounted side by side will give the 229-foot-tall (70-meter) rocket a span of 40 feet (12.2 meters). SpaceX estimates the Falcon Heavy can carry 48,940 pounds (22,200 kilograms) to geostationary transfer orbit, the destination that will likely bring the company the most revenue.

As mentioned elsewhere the payload numbers are going up as the vehicle is modified....

http://www.spacex.com/falcon-heavy

Payload to LEO 63,800kg 140,660 lb
Payload to Mars 16,800kg 37,040 lb

SpaceNut · 2017-05-09 13:18:25

bump Time is ticking and yet we still do not here Nasa being capable of a manned flight in the near future with SLS.....So where are the other rocket makers with this?

Oldfart1939 · 2017-05-09 13:44:46

SpaceNut-

Especially when the SLS has slipped again! Earliest launch date is now 2019.

Terraformer · 2017-05-09 14:36:41

I suspect the two passengers for the SpaceX moonshot won't be paying the full cost. What better way for SpaceX to show off it's new rocket and embarrass the competition? It wouldn't surprise me if they revealed a fully costed Lunar landing plan upon it's success, on the expectation of finding a Congress who are very receptive to a return mission.

louis · 2017-05-09 16:06:22

I have always thought it makes sense to develop lunar tourism as a proving ground for Mars landing, settlement and ISRU technology. The two can go forward in parallel. Mars is the big serious prize but the Moon is a respectable runner up.

Terraformer wrote:

I suspect the two passengers for the SpaceX moonshot won't be paying the full cost. What better way for SpaceX to show off it's new rocket and embarrass the competition? It wouldn't surprise me if they revealed a fully costed Lunar landing plan upon it's success, on the expectation of finding a Congress who are very receptive to a return mission.

SpaceNut · 2017-05-09 16:18:46

I think a modified Cygnus with docking ports on both ends packed with the supplies that the crew will need puts less strain on the Dragons life support that would be used for crew and propulsion via a cargo dragon modified unit to dock at the other port.

The modified cygnus would sport the panels on the sides of the unit with station keeping on the sides as small thrusters while waiting for the dragon crew to dock in orbit.

Oldfart1939 · 2017-05-09 16:42:01

Somehow--I suspect that Musk's ego would get in the way of that proposal--"not invented here." Same problem NASA seems to have.

SpaceNut · 2017-05-09 18:34:16

Ya that old bug.....

I would hope that the other old contractors are not just waiting around for Nasa to grant a contract to Rif a proposal for an aniversary date....

Boeing has the Starliner capsule but its only good enough for a quick LEO use...

Lockheed aside from the Orion it has no other capsule.

ATK / Orbital does not have a capsule but it does have a very adaptable cargo container design.

All three have launchers capable of at least LEO.

Are there any other players that can get us there?

Oldfart1939 · 2017-05-12 21:55:18

NASA will NOT fly the EM-1 mission with a crew, and even, then it's slipped into 2019. NASA also stated that they thought Trump was joking about a manned 2024 mission to Mars. Why can't they get a little more motivated to accomplish SOMETHING?

Buzz Aldrin stated that NASA should "pull the plug" on supporting the ISS, and allow private contractors to take it over. NASA seems dead in spirit.

Oldfart1939 · 2017-05-13 08:57:04

Here's a spaceflight101.com reference to the decision to NOT send a crew up on EM-1. It's NOT about feasibility but all about money. NASA needs to cut several other programs in order to "make this happen," in my not so humble opinion.

http://spaceflight101.com/nasa-opts-for … d-to-2019/

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#76 2017-03-02 03:38:02

Re: Apollo 8, redux

#77 2017-03-02 07:33:59

Re: Apollo 8, redux

#78 2017-03-02 11:15:34

Re: Apollo 8, redux

#79 2017-03-02 11:23:22

Re: Apollo 8, redux

#80 2017-03-02 13:28:21

Re: Apollo 8, redux

#81 2017-03-02 13:33:55

Re: Apollo 8, redux

#82 2017-03-02 13:46:41

Re: Apollo 8, redux

#83 2017-03-04 21:36:36

Re: Apollo 8, redux

#84 2017-03-05 01:44:29

Re: Apollo 8, redux

#85 2017-03-05 08:36:03

Re: Apollo 8, redux

#86 2017-03-05 10:14:50

Re: Apollo 8, redux

#87 2017-03-05 20:40:48

Re: Apollo 8, redux

#88 2017-03-05 21:01:51

Re: Apollo 8, redux

#89 2017-03-05 21:03:43

Re: Apollo 8, redux

#90 2017-03-06 19:59:48

Re: Apollo 8, redux

#91 2017-04-30 14:26:23

Re: Apollo 8, redux

#92 2017-05-09 13:18:25

Re: Apollo 8, redux

#93 2017-05-09 13:44:46

Re: Apollo 8, redux

#94 2017-05-09 14:36:41

Re: Apollo 8, redux

#95 2017-05-09 16:06:22

Re: Apollo 8, redux

#96 2017-05-09 16:18:46

Re: Apollo 8, redux

#97 2017-05-09 16:42:01

Re: Apollo 8, redux

#98 2017-05-09 18:34:16

Re: Apollo 8, redux

#99 2017-05-12 21:55:18

Re: Apollo 8, redux

#100 2017-05-13 08:57:04

Re: Apollo 8, redux

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