NASA To Order More Soyuz Seats

RobertDyck · 2014-02-11 13:54:08

Innnnnteresting. Very innnnnteresting. Your linked article says carbon fibre cloth can withstand temperatures greater than 3000°F. Nextel 440 is rated up to 2500°F. According to this web page, use temperature is up to 5,000°F. Of course with any material, as you get close to it's melting temperature, tensile strength will decrease. But that web page says "use temperature". Woo hoo!

GW Johnson · 2014-02-11 18:51:54

Quaoar: "On-Orbit Repair and Assembly Facility" is posted 2-11-14 over at "exrocketman" now.

Re: heat shield cloth materials. Carbon fiber will go fairly easily to 4000 F, maybe 4500 F. Not so sure about 5000 F. Somewhere it sublimates, and that temperature is lower at lower pressures. I used carbon successfully as monolithic graphite at 4000 F and hundreds of atm pressure differences in solid rocket motors. As a carbon matrix / carbon fiber composite, Shuttle used it at about 4000 F in the nose cap and leading edge pieces. It is quite brittle and fragile in that composite form (ref Shuttle Columbia loss from LE damage). If you don't use it as a composite, be aware that it is quite leaky porous in most weaves.

Re: aerobraking at Mars. As long as you can handle factor-2 variability in aerobraking force achievable at any given speed and altitude, then this will work fine. If you cannot handle factor-2 variability, then I would advise not betting lives upon it until you know that you can handle that kind of variability. That variability directly affects deceleration achievable, and less directly, point of landing by exponential change effects.

GW

SpaceNut · 2014-02-11 22:36:37

quaoar wrote:

I ask to the engineers of this forum if supersonic retropropulsion can be avoided with an umbrella shield large enough.

you an look to the soyuz for the answer as the landing still needs to much much slower even still to allow for a safe landing.

RobertDyck the carbon fiber cloths are very interesting but holding shape by then self with out a backer panel does not seem all that possible. If we need a backer for the cloth to hold shape then we might want to add a thin coating of the goo that was going to be used by the shuttle incase of tile problems. We could spread it onto the surface of a formed fabric panel shape then cure it with an oven or even lasers to make it hard. Then bolt it onto the ship for landing....

We might even try using a 3D printer with the goo to make the panels without the fabric or panel backer.

RobertDyck · 2014-02-11 23:10:33

Carbon fibre cloth does not require a backer panel. It does require ribs, like a parasol or umbrella. I'm thinking of titanium alloy, because it can withstand heat and it's springy. Inconel (nickel/chrome alloy) can actually withstand more heat, but it's as heavy and stiff as stainless steel. I could get into detail properties, but the web site linked above simply says "high temperature alloy". Good enough.

GW Johnson raised some real issues. I was concerned that carbon fibre could withstand more than 3000°F, but not quite 5000°F. Sales people like to quote absolute maximum, without telling you the catch. Mr Johnson reports it can reliably handle 4000°F. Ok. Carbon fibre cloth is stiff, but not nearly as brittle as RCC. It's strength is along the length of the fibre, not so much laterally. But cloth stretched between umbrella ribs? That emphasizes its strength. So no backer needed. But GW Johnson also reported it's leaky porous. Hard to weave a tight fabric when the threads are so stiff. But there are some interesting weaves. Many weaves made commercially are designed to be impregnated with epoxy, so made porous on purpose. It should be sufficient for aerocapture.

GW Johnson · 2014-02-13 09:40:21

About the only other issue is fiber elongation capability. My information may have been superseded in recent years, but 20+ years ago, carbon fiber had low elongation, making brittle failure of structures made with it a serious liability. It was popular in organic composites because of its high modulus of elasticity, which led to stiffer structures. It was/is popular in carbon-carbon composites because of its far higher usage temperatures.

Both applications suffered from the low elongation/brittle failure problem. Seems like I remember elongation-at-failure being 1-2% for carbon, 2-3% for kevlar, and 6+% for nylon. Those figures had direct impact on the shock-load behavior of tow lines made with the stuff. It also affects the radius of a fold made with the cloth. Too sharp a radius, and you fracture the fibers in the cloth. This shows up in the size of the cardboard tube the cloth comes rolled upon, and in the radii of structures you can make with it.

Woven-fabric porosity as a chute (or heat shield?) is not a killer problem. Although you have to deal with it. Finer weave reduces direct flow-through porosity. This is a compromise issue in supersonic parachutes. The ringsail is a variant on the older ribbon chute. Each panel is low porosity, but there have to be mahjor flowing gaps for aero stability in that application. Most of those are kevlar to take some heat, at the cost of serious opening-shock risks of destruction. If heat is not an issue, nylon is the better choice, being far less susceptible to opening shock damage.

I would think a fabric heat application would be similar in many ways to the supersonic parachute. You can design-out opening shock by deploying before start of entry, but the aero-stability of an extended lightweight and flexible surface like that may well require gaps, similar to a supersonic chute. In the heat shield application, gaps will let very high-energy plasma through, although at reduced Mach and somewhat limited quantity. Heat-sinking effects will be very important to survive that sort of thing. Using the old rule of thumb, you will have to deal with 5000 K (effective) gas at the start of a 5 km/s entry at Mars, and about 2000-3000 K at 2-3 km/s where peak heating occurs. Fortunately, the W/sq.cm are far lower at Mars than here.

GW

RobertDyck · 2014-02-13 11:36:50

GW Johnson wrote:

you will have to deal with 5000 K (effective) gas at the start of a 5 km/s entry at Mars, and about 2000-3000 K at 2-3 km/s where peak heating occurs.

That sounds like a perfect match for carbon fibre cloth. Woo hoo!

Quaoar · 2014-02-13 16:06:38

GW Johnson wrote:

Quaoar: "On-Orbit Repair and Assembly Facility" is posted 2-11-14 over at "exrocketman" now.

GW

Fantastic GW!!!

Last edited by Quaoar (2014-02-13 16:09:37)

RGClark · 2014-02-26 13:33:06

I suppose this should be in the thread discussing lightweight heat shields/decelerators for Mars but here is an another example, HIAD (Hypersonic Inflatable Aerodynamic Decelerators):

NASA Podcasts
NASA X: IRVE-3 1.30.13

Dr. Cheatwood: This concept would be coming back from the station, so entering at 7 1/2 kilometers a second, just like we were talking about at Mars. It would be bringing in anywhere from 3 1/2 to 5 metric tons, just like we were talking about at Mars. It would be between 8 and 10 meters in diameter, that actual HIAD, just like we were talking about at Mars. And we'll see heating of 25, 30, maybe higher, 35, 40 watts. So it's a very similar environment to Mars for that application. So we can do this flight test from the station for a very reasonable cost, and it demonstrates an ability to bring larger volumes and masses down from the station than we currently have, and it demonstrates that we could do this mission at Mars.
Pulley: With a successful heart mission researchers feel that they may have enough information and knowledge to proceed for the ultimate goal, which would mean seeing a HIAD at Mars.
Dr. Cheatwood: I believe in the technology. And, you know, I think, you know, if somebody wanted to give me a budget and say, "get us to Mars with humans in 2020," I think we could get there on this technology. I can't speak for other technologies. But no, I think we could get there.

http://www.nasa.gov/multimedia/podcasti … -0103.html

This is the transcript of this video:

NASA 360 | Hypersonic Inflatable Aerodynamic Decelerators (HIAD) [HD].
http://www.youtube.com/watch?v=hJUd3zanD8k

While I appreciate these inflatable heat shields allow you to get heavier mass to Mars, I've never seen any architecture for a manned Mars missions that only required to get 5 metric tons to the Martian surface.

Bob Clark

GW Johnson · 2014-02-26 15:06:05

7 km/s entry at Mars seems high. Isn't 5 km/s closer to the "typical" direct interplanetary transfer entry?

If you can guess a hypersonic drag coefficient for the inflatable-or-extendable fabric heat shield shape (somewhere in the 1.4 to 1.7 range), and you have accurate figures for both entry speed and entry trajectory angle below horizontal, the old Julian Allen warhead entry analysis I use does a decent ballpark job telling you peak gees, peak heating, and end-of-hypersonics (about local Mach 3). You'll have those quantities plus the altitudes and speeds at which they occur.

Peak decel gees and heat shield diameter, coupled with density at peak gee altitude, give you the average pressure exerted over the heat shield. You can figure stagnation pressure pretty easily, and your average ought to be between stagnation and nothing, probably about half stagnation as a ballpark guess. You can even guess a pressure distribution from that.

The pressure distribution and geometry lead you to structural stress/strain analysis. The pressure distribution and geometry also lead you to a ballpark estimate of gas leakage due to porosity. That and the old rule of thumb that gas temperature in deg K is speed in m/s divided by 10, gives you a shot at a ballpark heat transfer analysis.

I'd be very wary of impregnating the fabric heat shield with any resins. You lose flexibility and impact damage resistance that way. If you need to impregnate it, use an elastomer. I'd go with a hard char-forming solids-doped silicone, myself. Probably not exactly DC-93-104, but something like it.

None of that takes any account of factor-2+ variability in the high altitude density profile at Mars, something that does not happen here. Your end of hypersonics point will vary exponentially with things like that.

Most of the ballistic coefficient stuff I have done recently suggests that ballistic coefficients are larger at larger vehicle masses, shapes and proportions being otherwise unchanged. It's a square-cube law thing. When those get too big, on Mars chutes get to be quite useless post-hypersonics. The way out of that dilemma is supersonic retropropulsion technology. There'll be a point where square-cube scaling won't let you build a survivable inflatable/extendable heat shield for vehicles that large.

My own studies are not for a minimalist mission, but more like a mission with an orbital transport and multiple landers. Those landers typically exceed 30 tons, and approach 100 tons, depending upon propulsion choice and payload size. Their ballistic coefficients typically fall in the 300-500 kg/sq.m range. The probe folks at JPL seem to need Rube Goldberg stuff above about 100 kg/sq.m. So, that's the "breakpoint" where you start needing to use supersonic retropropulsion instead of chutes.

The inflatable/extendable heat shield is a way to reduce ballistic coefficients at larger vehicle mass. But, you will hit that 100 kg/sq.m limit rather quickly, even with heat shields like that. I rather doubt a 5 ton lander would be very useful.

GW

Terraformer · 2014-02-27 03:34:35

Well, that depends on how you're doing things, doesn't it? If you're deploying inflatable modules for your habitat, and then setting up life support for them afterwrods, and have ISRU that allows you to ferry things down, you may not need a massive lander.

SpaceNut · 2014-02-27 18:35:23

RGClark thanks for the hypercone post

GW Johnson I am reminded of the inflateable airplane mission that would after inflation spray a thermal setting epoxy into the wing to make it ridgid. I think that is just the ticket to make the cone keep shape under shifting wind flow conditions.

SpaceNut · 2015-01-27 19:29:37

Back to the cost of depending on Russia for flight seats to the ISS or anywhere...

NASA: Flying Astronauts With Boeing and SpaceX Will Save Us $12 Million Per Seat

Since the retirement of the Space Shuttle fleet in 2011, the Russian Soyuz spacecraft has been the only means for NASA to send its astronauts to the International Space Station. NASA is currently paying Roscosmos, the Russian space agency, about $70 million per seat for the space taxi service. The goal of NASA's Commercial Crew program is to prepare private American companies—in this case Boeing and SpaceX—to carry astronauts to orbit, and Monday's conference served as a status report on the endeavor. And at least financially, it's going well: NASA Commercial Crew program manager Kathy Lueders said at the press conference that the $5 billion that would be split between Boeing and SpaceX breaks down to about $58 million per seat.
SpaceX and Boeing were awarded commercial crew contracts last September with the goal of beginning to fly astronauts to and from the ISS by 2017. The space station is expected to stay in orbit until at least 2024. After that, Bolden said, he expects NASA to turn all manned operations in low Earth orbit over to private enterprise, with private vehicles continuing to carry crews and cargo to private space stations such as those planned by Bigelow Aerospace.
The first unmanned orbital test flight of the CST-100 is already on the Atlas V launch manifest and is planned for the 74th flight of the rocket. The first manned CST-100 mission is planned for the 80th Atlas V flight, which should happen around 2017.

Budgets and contracts
SpaceX is receiving $2.6 billion of the $6.8 billion total contract, with Boeing awarded the other $4.2 billion.

Dragon flight cost= expected to be around $140 million for 7 passengers is $20 million per person and fly up to six missions rotating crews on the space station for is cut of $2.6 billion.
Possible launch count is roughly 18 for the money.

CST-100 Flight cost= currently about $133 million. Divide it by NASA's four-person crew requirement, and you get $33 million per seat.
Possible launch count is roughly 31 for the money.

Nasa, Boeing, SpaceX outline Objectives to Station Flights

Last edited by SpaceNut (2015-01-28 20:38:36)

SpaceNut · 2015-01-28 20:47:34

http://www.planetary.org/blogs/jason-da … lries.html

To begin flying regular, paid crew missions to the ISS, Boeing and SpaceX must each complete two demonstration missions with their respective spacecraft, the CST-100 and Dragon Version 2. The first demo flights won't have crews. Even though SpaceX has already been flying Dragon cargo missions to the ISS since 2012, they still have to complete this step since the crewed Dragon variant has a different design. The second flights will carry astronauts. Exactly how many and what type—NASA or commercial—is still being decided.
Boeing's CST-100 launches atop the Atlas V, a rocket used heavily by the Air Force and NASA for a variety of missions. Flying on the Atlas V means booking a launch slot far in advance. As such, Boeing may get a paperwork thumbs-up before SpaceX does.
Boeing is aware of their impending bottleneck, and may soon begin work on a new launch vehicle for the CST-100.

SpaceNut · 2019-01-04 22:27:38

Here it is 2019 and we will finally see the fruit of rocket launching companies soon with manned flights starting to the iss and hopefully to other destinations....

Oldfart1939 · 2019-01-05 00:12:44

The final Iridium next launch is still on schedule for the 8th. There's been some speculation that the AF does the range operation and SpaceX DOES have the FAA license for the unmanned Demo. The paper shufflers need to get out of the way and enjoy a vacation.

SpaceNut · 2019-01-05 10:52:34

Paper shuffle can be blamed on our governements handling of whom goes when..

I truely want the rest of the space industry to follow the lead and start investing to garner the funds from profits to change space as its been shown will work rather than a feed and gravy trough that they are too fond of...

Oldfart1939 · 2019-01-05 22:30:51

SpaceNut wrote:

Paper shuffle can be blamed on our governements handling of whom goes when..
I truely want the rest of the space industry to follow the lead and start investing to garner the funds from profits to change space as its been shown will work rather than a feed and gravy trough that they are too fond of...

Couldn't agree more with your statement!

SpaceNut · 2019-01-06 10:03:27

Its been along time coming to a close and was the right thing to do when shuttle stopped flying but its also why the other partners needed to step up as well so as to give them the means to do more on the station long ago for human space flight with control of there own ships going to the station.

The change of direction to get commercial space flight going as well was the right choice as well but we need more change in the overall picture of providers as we are still in the eggs are all in one basket currently.

SpaceNut · 2019-01-06 13:08:57

Behold! SpaceX's 1st Crew Dragon Spaceship Is On the Launchpad much like Beam delivered to the station for basically an inspection of it....test flight for NASA targeted for Jan. 17 . That schedule, however, may be delayed due to the ongoing partial government shutdown that has shuttered much of the U.S. space agency. With the potential timeline for the Crew Dragon demonstration flight being pushed back into early February...which is still ahead of the previously scheduled for June of this year.

Boeing, which has its own crewed ship for NASA, called the CST-100 Starliner, that is scheduled to make an uncrewed test flight in March, with crewed flight later this year.

SpaceNut · 2019-01-06 13:16:36

Space x is not the only one's having issues as Government Shutdown Delays Commercial Rocket Launch

Exos Aerospace had planned to launch its SARGE suborbital rocket Jan. 5 from Spaceport America in New Mexico. That launch has been delayed to Feb. 9, 2019..delay was the inability of the company to get its existing launch license from the Federal Aviation Administration's Office of Commercial Space Transportation modified as limited supplies and high costs of helium, used to pressurize the vehicle's propulsion system; delaying the launch reduces the chance that helium would be wasted on a wind-related launch scrub.

The rocket reached a peak altitude of 28 kilometers — far less than the planned 80 kilometers — before gliding back to a landing near the launch site. Had the GPS receiver not malfunctioned, the company said the rocket could have flown to nearly 90 kilometers.

New Mars Forums

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#26 2014-02-11 13:54:08

Re: NASA To Order More Soyuz Seats

#27 2014-02-11 18:51:54

Re: NASA To Order More Soyuz Seats

#28 2014-02-11 22:36:37

Re: NASA To Order More Soyuz Seats

#29 2014-02-11 23:10:33

Re: NASA To Order More Soyuz Seats

#30 2014-02-13 09:40:21

Re: NASA To Order More Soyuz Seats

#31 2014-02-13 11:36:50

Re: NASA To Order More Soyuz Seats

#32 2014-02-13 16:06:38

Re: NASA To Order More Soyuz Seats

#33 2014-02-26 13:33:06

Re: NASA To Order More Soyuz Seats

#34 2014-02-26 15:06:05

Re: NASA To Order More Soyuz Seats

#35 2014-02-27 03:34:35

Re: NASA To Order More Soyuz Seats

#36 2014-02-27 18:35:23

Re: NASA To Order More Soyuz Seats

#37 2015-01-27 19:29:37

Re: NASA To Order More Soyuz Seats

#38 2015-01-28 20:47:34

Re: NASA To Order More Soyuz Seats

#39 2019-01-04 22:27:38

Re: NASA To Order More Soyuz Seats

#40 2019-01-05 00:12:44

Re: NASA To Order More Soyuz Seats

#41 2019-01-05 10:52:34

Re: NASA To Order More Soyuz Seats

#42 2019-01-05 22:30:51

Re: NASA To Order More Soyuz Seats

#43 2019-01-06 10:03:27

Re: NASA To Order More Soyuz Seats

#44 2019-01-06 13:08:57

Re: NASA To Order More Soyuz Seats

#45 2019-01-06 13:16:36

Re: NASA To Order More Soyuz Seats

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