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A propellant tank pressurized to 2 atm expels the LH 2 coolant into the exchanger without the need for turbopumps. That's how you know they're working. Free radical hydrogen H has half the molecular weight of H 2. When a fish comes down with Ich or other types of skin problems, the fish will swim up next to the shrimp and patiently tread water while waiting for the shrimp to clean its body of parasites. Naoto Kimura mentioned that "Oh-gee Whiz" would be a good brandname for space toilet.

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These latter and simpler processes would be completed largely autonomously. Low Earth orbit LEO is reachable from the surface of the Earth in eight minutes, and geosynchronous orbit—the beginning of HEO—is reachable within eight hours. The proximity of LEO and HEO to the seven billion people on Earth and their associated economic activity is a strong indication that cislunar space will become the future economic home of humankind.

In the architecture described here, raw material is slowly delivered to HEO over time via a fleet of regolith-processing, electrostatically-propelled vehicles; by contrast, humans arrive quickly to HEO from Earth.

This NEO-based ISRU architecture could be the foundation of massive economic growth off-planet, enabling the construction mostly from asteroidal materials of massive solar power stations, communications hubs, orbital hotels and habitats, and other facilities. One of the ideas I had been thinking of blogging about was the thought of augmenting Enhanced Gravity Tractor EGT asteroid deflection with in-situ derived propellants. The gravitation attraction force is usually the bottleneck in how fast you can do an asteroid deflection, but in some situations the propellant load might matter too.

That would imply getting somewhere between 16x the thrust per unit time as running the same amount of power through the HET. One nice thing is that some of this material can be gathered while landing to gather the additional mass for the enhanced gravity tractor. Field-emission electric propulsion , a type of Colloid thruster. They typically use caesium or indium as the propellant due to their high atomic weights, low ionization potentials and low melting points.

This ion rocket accelerates ions using the electric potential maintained between a cylindrical anode and negatively charged plasma which forms the cathode.

To start the engine, the anode on the upstream end is charged to a positive potential by a power supply. Simultaneously, a hollow cathode at the downstream end generates electrons. As the electrons move upstream toward the anode, an electromagnetic field traps them into a circling ring at the downstream end.

This gyrating flow of electrons, called the Hall current, gives the Hall thruster its name. The Hall current collides with a stream of magnesium propellant, creating ions. As magnesium ions are generated, they experience the electric field between the anode positive and the ring of electrons negative and exit as an accelerated ion beam.

A significant portion of the energy required to run the Hall Effect thruster is used to ionize the propellant, creating frozen flow losses. On the plus side, the electrons in the Hall current keep the plasma substantially neutral, allowing far greater thrust densities than other ion drives. Gridded Electrostatic Ion Thruster. Potassium seeded argon is ionized and the ions are accelerated electrostatically by electrodes. Other propellants can be used, such as cesium and buckyballs.

Though it has admirably high exhaust velocity, there are theoretical limits that ensure all Ion drives are low thrust. It also shares the same problem as the other electrically powered low-thrust drives.

In the words of a NASA engineer the problem is "we can't make an extension cord long enough. Low powered ion drives can get by with solar power arrays, all ion drive space probes that exist in the real world use that system. Researchers are looking into beamed power systems, where the ion drive on the spaceship is energized by a laser beam from a remote space station. And it suffers from the same critical thrust-limiting problem as any other ion engine: Which means that it has a net space charge which repels any additional ions trying to get in until the ones already under acceleration manage to get out, thus choking the propellant flow through the thruster.

The upper limit on thrust is proportional to the cross-sectional area of the acceleration region and the square of the voltage gradient across the acceleration region, and even the most optimistic plausible values i. You can only increase particle energy so much; you then start to get vacuum arcing across the acceleration chamber due to the enormous potential difference involved.

So you can't keep pumping up the voltage indefinitely. To get higher thrust, you need to throw more particles into the mix. The more you do this, the more it will reduce the energy delivered to each particle. The illustrated design uses a combination of microwaves and spinning magnets to ionize the propellant, eliminating the need for electrodes, which are susceptible to erosion in the ion stream.

The propellant is any metal that can be easily ionized and charge-separated. A suitable choice is magnesium, which is common in asteroids that were once part of the mantles of shattered parent bodies, and which volatilizes out of regolith at the relatively low temperature of K. The ion drive accelerates magnesium ions using a negatively charged grid, and neutralizes them as they exit. The grids are made of C-C, to reduce erosion. Since the stream is composed of ions that are mutually repelling, the propellant flow is limited to low values proportional to the cross-sectional area of the acceleration region and the square root of the voltage gradient.

A 60 MWe system with a thrust of 1. Colloids charged sub-micron droplets of a conducting non-metallic fluid are more massive than ions, allowing increased thrust at the expense of fuel economy.

This fictional ship is a species of Ion drive utilizing cadmium and powered by deuterium fusion. Looking at its performance I suspect that in reality no Ion drive could have such a high thrust. The back of my envelope says that you'd need one thousand ultimate Ion drives to get this much thrust. A working fluid such as hydrogen can be heated to 12, K by an electric arc.

Since the temperatures imparted are not limited by the melting point of tungsten, as they are in a sold core electrothermal engine such as a resistojet, the arcjet can burn four times as hot. However, the thoriated tungsten electrodes must be periodically replaced.

When used for mining beneficiation, regolith or ore is initially processed with a 1 Tesla magnetic separator and impact grinder 3. The arcjet can also be used for arc welding. This device works by generating microwaves in a cylindrical resonant, propellant-filled cavity, thereby inducing a plasma discharge through electromagnetic coupling. The discharge performs either mining or thrusting functions.

In its mining capacity, the head brings to bear focused energy, tuned at close quarters by the local microwave guides, to a variety of frequencies designed to resonate and shatter particular minerals or ice. In its electrothermal thruster MET capacity, the microwave-sustained plasma superheats water, which is then thermodynamically expanded through a magnetic nozzle to create thrust.

The MET needs no electrodes to produce the microwaves, which allows the use of water propellant the oxygen atoms in a steam discharge would quickly dissolve electrodes. MET steamers can reach seconds of specific impulse due to the high K discharge source temperatures, augmented by rapid hydrogen-oxygen recombination in the nozzle. Vortex stabilization produces a well-defined axisymmetric flow.

The illustration shows a microwave plasma discharge created by tuning the TM mode for impedance-matched operation. Regenerative water cooling is used throughout.

For pressures of 45 atm, each unit can produce 30 N of thrust. The thrust array contains such units, at 50 kg each. Power and Randall A. Chapman, Lewis Research Center, In a resistojet , propellant flows over a resistance-wire heating element much like a space heater or toaster then the heated propellant escapes out the exhaust nozzle. They are mostly used as attitude jets on satellites, and in situations where energy is more plentiful than mass. Tungsten, the metal with the highest melting point K , may be used to electric-resistance heat ore for smelting or propellant for thrusting.

In the latter mode, the resistojet is an electro-thermal rocket that has a specific impulse of 1 ksec using hydrogen heated to K. Internal pressures are 0. To reduce ohmic losses, the heat exchanger uses a high voltage 10 kV low current Once arrived at a mining site, the tungsten elements, together with wall of ceramic lego-blocks produced in-situ from regolith by magma electrolysis are used to build an electric furnace.

Tungsten resistance-heated furnaces are essential in steel-making. They are used to sand cast slabs of iron from fines magnetically separated from regolith , refine iron into steel using carbon imported from Type C asteroids , and remove silicon and sulfur impurities using CaAl 2 O 4 flux roasted from lunar highland regolith.

An e-beam beam of electrons is a versatile tool. It can bore holes in solid rock mining , impart velocity to reaction mass rocketry , remove material in a computer numerical control cutter finished part fabrication , or act as a laser initiator free electron laser. A wakefield electron accelerator uses a brief femtosecond laser pulse to strip electrons from gas atoms and to shove them ahead.

Other electrons entering the electron-depleted zone create a repulsive electrostatic force. The initial tight grouping of electrons effectively surf on the electrostatic wave.

Wakefield accelerators a few meters long exhibit the same acceleration as a conventional rf accelerator kilometers in length. In a million-volt-plus electron beam the electrons are approaching lightspeed, so the term relativistic electron beam is appropriate.

The wakefield can be used as an electrothermal rocket similar in principle to the arcjet, but far less discriminating in its choice of propellant. Fusion propulsion uses the awesome might of nuclear fusion instead of nuclear fission or chemical power.

They burn fusion fuels , and for reaction mass use either the fusion reaction products or cold propellant heated by the fusion energy. There is a discussion of magnetic nozzles here.

For one thing, forget muon catalyzed fusion. The temperature of the exhaust will not be high enough for torch ship like performance. You might use a heavy ion beam driven inertial confinement fusion pulse drive , or a Z-pinch fusion pulse drive. I don't think magnetic confinement fusion will work — you are dealing with a such high power levels I don't think you want to try confining this inside your spacecraft because it would melt.

D-T deuterium-tritium fusion is not very good for this purpose. If we assume we need to keep the temperature of the drive machinery below K to keep iron from melting, or diamond components from turning into graphite , you would need all non-expendable drive components to be located at least meters away from the point where the fusion pulses go off. For a terawatt torch, this means you need to deal with gigawatts of radiation.

You need a meter radius bell for your drive system to keep the temperature down. This lets you get away with a 66 meter radius bell for a terawatt torch. To minimize the amount of x-rays emitted, you need to run the reaction at keV per particle, or 1. If it is hotter or colder, you get more x-rays radiated and more heat to deal with. This could provide 1 G of acceleration to a spacecraft with a mass of at most 26, kg, or If we say we have a payload of 20 metric tons and the rest is propellant, you have 50 hours of acceleration at maximum thrust.

Note that this is insufficient to run a 1 G brachistochrone. Burn at the beginning for a transfer orbit, then burn at the end to brake at your destination. Note that thrust and rate of propellant flow scales linearly with drive power, while the required bell radius scales as the square root of the drive power.

If you use active cooling, with fluid filled heat pipes pumping the heat away to radiators, you could reduce the size of the drive bell somewhat, maybe by a factor of two or three. Also note that the propellant mass flow is quite insufficient for open cycle cooling as you proposed in an earlier post in this thread. Due to the nature of fusion torch drives, your small ships may be sitting on the end of a large volume drive assembly. The drive does not have to be solid — it could be a filigree of magnetic coils and beam directing machinery for the heavy ion beams, plus a fuel pellet gun.

The ion beams zap the pellet from far away when it has drifted to the center of the drive assembly, and the magnetic fields direct the hot fusion plasma out the back for thrust. One gigawatt of power requires burning a mere 0. Note that Tritium has an exceedingly short half-life of Use it or lose it. Most designs using Tritium included a blanket of Lithium to breed more fresh Tritium fuel. Fuel is Hydrogen and Boron Bombard Boron atoms with Protons i. Current research indicatates that there may be some neutrons.

Paul Dietz says there are two nasty side reactions. One makes a Carbon atom and a gamma ray, the other makes a Nitrogen atom and a neutron. The first side reaction is quite a bit less likely than the desired reaction, but gamma rays are harmful and quite penetrating.

The second side reaction occurs with secondary alpha particles before they are thermalized. The Hydrogen - Boron reaction is sometimes termed "thermonuclear fission " as opposed to the more common "thermonuclear fusion". A pity about the low thrust. The fusion drives in Larry Niven's "Known Space" novels probably have performance similar to H-B Fusion, but with millions of newtons of thrust. The catch is, you have to arrange for the protons to impact with keV of energy, and even then the reaction cross section is fairly small.

Shoot a keV proton beam through a cloud of boron plasma, and most of the protons will just shoot right through. Either way, you won't likely get enough energy from the few which fuse to pay for accelerating all the ones which didn't.

Now, a dense p-B plasma at a temperature of keV is another matter. With everything bouncing around at about the right energy, sooner or later everything will fuse. But containing such a dense, hot plasma for any reasonable length of time, is well beyond the current state of the art.

We're still working on 25 keV plasmas for D-T fusion. If you could make it work with reasonable efficiency, you'd get on the order of ten gigawatt-hours of usable power per kilogram of fuel. Graduate Student Alex H. Cheung is looking into turning this concept into a propulsion system. Fuel is helium 3 and deuterium. There are five general methods for confining plasmas long enough and hot enough for achieving a positive Q more energy out of a reaction than you need to ignite it, "break even":.

Of these reactions, the fusion of deuterium and tritium D-T , has the lowest ignition temperature 40 million degrees K, or 5. Another disadvantage is that 3 He is so rare that , tonnes of regolith scavenging would be needed to obtain a kilogram of it. Alternatively, helium 3 can be scooped from the atmospheres of Jupiter or Saturn.

Deuterium, in contrast, is abundant and cheap. Its advantage is that is suffers no side reactions and emits no neutrons, and hence the reactor components do not become radioactive. The 6 Li-H reaction is similarly clean. However, both the H-B and 6 Li-H reactions run hot, and thus ion-electron collisions in the plasma cause high bremsstrahllung x-ray losses to the reactor first wall. There are two types of mission.

The bottom line is that inertial confinement fusion is far superior to magnetic confinement fusion. Inertial Confinement Fusion is in the Pulse section. A Farnsworth-Bussard fusor is little more than two charged concentric spheres dangling in a vacuum chamber, producing fusion through inertial electrostatic confinement. Electrons are emitted from an outer shell the cathode , and directed towards a central anode called the grid. The grid is a hollow sphere of wire mesh, with the elements magnetically-shielded so that the electrons do not strike them.

Instead, they zip right on through, oscillating back and forth about the center, creating a deep electrostatic well to trap the ions of lithium 6 and hydrogen that form the fusion fuel. Half of this energy is bremsstrahlung X-rays, which must be captured in a lithium heat engine. The other half are isotopes of helium 3 He and 4 He , each at about 8 MeV. Since both products are doubly charged, a 4 MeV electric field will decelerate them and produce two electrons from each, producing an 18 amp current at extremely high voltage.

An electron gun using this 4 million volt energy would emit electrons at relativistic speeds. This beam dissipates quickly in space, unless neutralized by positrons or converted into a free electron laser beam. Jameson, Journal of Propulsion and Power, v. Philo Farnsworth, the farm boy who invented the television, spent his last years in a lonely quest to attain break-even fusion in his ultra-cheap fusor devices.

His ideas are enjoying a renaissance, thanks to Dr. Bussard, and working fusion reactors are making an appearance in high school science fairs. A magnetic bottle contains the fusion reaction. Very difficult to do. Researchers in this field say that containing fusion plasma in a magnetic bottle is like trying to support a large slab of gelatin with a web of rubber bands.

Making a magnetic bottle which has a magnetic rocket exhaust nozzle is roughly times more difficult. Since the engine is using a powerful but tightly controlled magnetic field, it might be almost impossible to have a cluster of several magnetic confinement fusion engines. The magnetic fields will interfere with each other. There are two main forms of magnetic bottles: Helium 3 is an isotope of helium, and deuterium abbreviated D is an isotope of hydrogen.

The mirror design shown is a tube of 11 Tesla superconducting magnetic coils, with choke coils for reflection at the ends.

The magnets weigh 12 tonnes, plus another 24 tonnes for 60 cm of magnet radiation shielding and refrigeration. These losses limit the Q to about unity and prevent ignition. This is not a problem for propulsion, since reaching break-even is not required to achieve thrust. The plasma is held in stable energy equilibrium by the constant injection of auxiliary microwave heating. The Q can be improved by a tandem arrangement: Mirrors improved by vortex technology, called field-reversed mirrors, introduce an azimuthal electron current which creates a poloidal magnetic field component strong enough to reverse the polarity of the magnetic induction along the cylindrical axis.

This creates a hot compact toroid that both plugs end losses and raises the temperature of the scrape-off plasma layer fourfold to 2.

Mirrors, like all magnetic fusion devices, can readily augment their thrust by open-cycle cooling. Schaffer, General Atomics Project , Dec Of all the fusion reactions, the easiest to attain is a mixture of the isotopes of hydrogen called deuterium and tritium D-T.

The remaining energy neutron, bremsstrahlung, and cyclotron radiation must be captured in a surrounding jacket of cold dense Li plasma. The heated lithium is either exhausted as open-cycle coolant, or recirculated through a heat engine to generate the power needed for the microwave plasma heater.

The 2 GWth magnetically-confined reactor shown uses eight poloidal superconducting 30 Tesla coils, twisted into a Tokamak configuration. These weigh 22 tonnes with stiffeners and neutron shielding. The pulsed D-T plasma, containing tens of megamps, is super-heated by 50 MW of microwaves or colliding beams to 20 keV.

The Q gain factor is Closed field line devices such as this can ignite and burn, in which case the Q goes to infinity and microwave heating is no longer needed. However, since ignition is inherently unstable once ignited, the plasma rapidly heats away from the ignition point , the reactor is kept at slightly below ignition.

More advanced vortex designs, which do away with the first wall, separate the hot fusion fuel from the cool lithium plasma by swirling the mixture. The Tokamak used in High Frontier is a smaller lower tech version of the Lewis design, which uses aneutronic 3 He-D fuel. To make the fusion reactor into a fusion rocket, the fusion energy has to be used to accelerate reaction mass.

Pure fusion rockets use the fusion products themselves as reaction mass. Fusion afterburners and fusion dual-mode engines use the fusion energy plasma thermal energy, neutron energy, and bremsstrahlung radiation energy to heat additional reaction mass. So afterburners and dual-mode reduce the exhaust velocity in order to increase thrust. Stuhlinger notes that high-thrust mode allows fast human transport but low payloads while high-specific-impulse mode allows cargo vessels with large payload ratios but long transit times.

He compares these to sports cars and trucks, respectively. Pure fusion rockets use just the plasma thermal energy, and just the fusion products as reaction mass. The advantage is incredibly high exhaust velocity though sometimes it can be too high. For our thermal calculations, we will use the percentage of the fuel mass that is transformed into energy for E.

This will make m into 1, and turn the equation into:. D-T fusion has a starting mass of 5. In meters per second 0. Fusion afterburners use just the plasma thermal energy, but adds extra cold reaction mass to the fusion products. This is based on information from physicist Luke Campbell. For a given mission with a given delta V requirement, it is possible to calculate the optimum exhaust velocity. In many cases a fusion engine has thrust too low to be practical, but the exhaust velocity is way above optimal.

It is possible to increase the thrust at the expense of the exhaust velocity and vice versa by shifting gears. An afterburner for a fusion engine is a way to shift gears. A pure fusion engine just uses the hot spent fusion products as the reaction mass. An afterburner fusion engine has a second plasma chamber the afterburner constantly filled with some cold propellant generally hydrogen or water, but you can use anything that the spend fusion plasma can vaporize.

The hot spent fusion products are vented into the afterburner, heating up the cold propellant. The average temperature goes down decreasing the exhaust velocity while the propellant mass flow goes up increasing the thrust. The propellant mass flow increases naturally because instead of just sending the fusion products out the exhaust nozzle, you are sending out the fusion products plus the cold propellant.

The contents of the afterburner are sent out the exhaust nozzle and Newton's Third Law creates thrust. That is, if the engine is burning 0. The spent fusion products mDot is 9. Usually the spent fusion product mass will be miniscule compared to the cold propellant mass. That is the reason the thrust was so miserably low to start with. Dual-mode use the neutron and bremsstrahlung radiation energy which is otherwise wasted to heat cold reaction mass, in parallel to the fusion products exhaust.

In addition a Dual-mode can switch into Pure Fusion mode. The neutron and bremsstrahlung energy produced by the fusion reaction is basically wasted energy when it comes to rocket propulsion.

A dual-mode engine can switch from pure fusion mode into harvesting mode. This means additional cold propellant mass is moved around the fusion reaction chamber to be heated by the neutrons and bremsstrahlung radiation.

This augments the thrust, at the expense of increasing the propellant usage rate. There are some designs that try to harvest the wasted neutron and bremsstrahlung energy by attempting to turn it into electricity instead of thrust. But sometimes it is not worth it. This requires a turbine and electrical generator, which cuts into the payload mass.

Fictional magnetic bottle fusion drive from the Attack Vector: It uses an as yet undiscovered principle to direct the heat from the fusion reaction out the exhaust instead of vaporizing the reaction chamber. The latter increases specific impulse exhaust velocity at the expense of thrust. In the illustration, the spikes are solid-state graphite heat radiators, the cage the spikes emerge from is the magnetic bottle, the sphere is the crew quarters and the yellow rectangles are the retractable power reactor heat radiators.

The ship in the lower left corner is signaling its surrender by deploying its radiators. The sparse details I managed to find were from the short story Drive. The inventor mounted the newly-invented drive in a small interplanetary yacht whose living space was smaller that Epstein's first Mars apartment. Which was quite a few times higher than Epstein was expecting. He was instantly pinned by the acceleration and could not turn the drive off. By this time Epstein was long dead and the yacht can still be seen by a powerful enough telescope on its way to nowhere.

The drive was some species of fusion drive using Epstein's innovative "magnetic coil exhaust". After 10 minutes they had dropped to After 2 more minutes Now comes conjecture on my part.

Please note this is totally non-canon and unofficial, I'm just playing with numbers here. I made lots of assumptions. I assumed the yacht had a mass ratio of 4, since Jerry Pournelle was of the opinion that was about the maximum for an economical spacecraft.

I also assumed the yacht had a mass of 15 metric tons, because that was the wet mass of the Apollo Command and Service module. Looking over the theoretical maximum exhaust of various fusion reactions we find we are in luck. Pretty much all of them can manage more than that exhaust velocity, with the exception of Deuterium-Helium 3. Of course the thrust power is a whopping 5. The legendary Scott Manley does his own analysis of Epstein's experimental ship in this video. Yes a fusion drive will give the needed performance but No the heat from the drive will vaporize the entire ship in a fraction of a second.

Independently of assuming a specific ship's mass and propellant fraction, he takes the hard canon facts of Epstein's experimental ship having an acceleration of 6. Start with mass ratio equation. We now have an equation with a single variable, V e! However, it's an ugly ass equation where V e appears both as a denominator in an exponent and a denominator in a nested fraction. Wolfram Alpha to the rescue! Erin Schmidt did a quick analysis of the Epstein-drive ship Rocinate not Epstein's experimental ship , hinging on some very loose assumptions.

He figures the thrust power is 11 terawatts. These use the heat generated from a nuclear reaction to heat up propellant. The nuclear reaction is controlled by adjusting the amount of free neutrons inside the mass of fissioning material. As a side effect, if you have a cluster of several such engines it is vitally important to have distance and neutron shields between them.

Otherwise the nuclear reaction in each engine will flare out of control due to the neutron flux from its neighbor engines.

It's a real simple concept. Put a nuclear reactor on top of an exhaust nozzle. Instead of running water through the reactor and into a generator, run hydrogen through it and into the nozzle. By diverting the hydrogen to a turbine generator 60 megawatts can be generated.

The reactor elements have to be durable, since erosion will contaminate the exhaust with fissionable materials. The exhaust velocity limit is fixed by the melting point of the reactor.

Hydrogen gives the best exhaust velocity, but the other propellants are given in the table since a spacecraft may be forced to re-fuel on whatever working fluids are available locally what Jerry Pournelle calls "Wilderness re-fuelling", Robert Zubrin calls "In-situ Resource Utilization", and I call "the enlisted men get to go out and shovel whatever they can find into the propellant tanks".

The value for "hydrogen" in the table is for molecular hydrogen, i. Atomic hydrogen would be even better, but unfortunately it tends to explode at the clank of a falling dust speck Heinlein calls atomic hydrogen "Single-H". Another reason to avoid hydrogen is the difficulty of storing the blasted stuff, and its annoyingly low density Ammonia is about eight times as dense!

The exhaust velocities are larger than what one would expect given the molecular weight of the propellants because in the intense heat they break down into their components. Ammonia is nice because it breaks down into gases Hydrogen and Nitrogen. Methane is nasty because it breaks down into Hydrogen and Carbon, the latter tends to clog the reactor with soot deposits. Water is most unhelpful since it doesn't break down much at all. John Schilling figures that as an order of magnitude guess, about one day of full power operation would result in enough fuel burnup to require reprocessing of the fissionable fuel elements.

Schilling also warns that there is a minimum amount of fissionable material for a viable reactor. Figure a minimum of 50 kilograms of HEU. This is because only the solid-core NTRs have solid reactor elements exposed to the propellant for heating. NASA could sidestep many of the impediments to a Mars mission if they could just get there faster.

But sluggish chemical rockets aren't cutting it — and to find what comes next, one group of engineers is rebooting research into an engine last fired in The energy liberated by burning chemical fuel brought astronauts to the moon, but that rocket science makes for a long trip to Mars. And although search for a fission-based shortcut dates back to the s, such engines have never flown.

Rather than burning fuel with oxygen, a nuclear fission reactor would serve as a powerful furnace, heating liquid hydrogen and expelling the resulting gas for thrust. How much oomph a rocket gets from its fuel depends largely on how fast it can hurl particles out the back, which in turn hinges on their mass.

And NTP's single or double hydrogen atoms would be up to a dozen times lighter than chemical rocket outputs. That atomic bean counting could add up to significant time savings. Unlike truly exotic propulsion proposals using antimatter or nuclear fusion , researchers have long considered nuclear fission rockets technologically feasible.

Concrete development began with the Atomic Energy Commission's Project Rover in — three years before NASA's founding — and continued with the NERVA rocket prototype, which fired for nearly 2 hours straight during ground tests before budget cuts ended development in The technology saw a brief revival in the late '80s and early '90s with the Space Nuclear Thermal Propulsion SNTP program, which also ran out of funding before flight testing.

But now, with interest turning back toward Mars, past research is finding new life in current projects. We're building upon really good work that was done back in that time frame," he told Space. Over the course of the contract, which extends through , BWXT will develop conceptual designs focusing on fuel elements and the reactor core.

The potential for trace levels of radioactivity in the engine exhaust means that engineers can no longer let clouds of hydrogen gas billow into the atmosphere.

Early, small-scale demonstrations will use non-nuclear hydrogen gas to test this exhaust-capturing method, but water from future nuclear tests could be decontaminated with off-the-shelf technology.

Engineers are also redesigning the fuel elements with new materials surrounding the uranium fuel particles, according to Witter. Rocket efficiency depends on temperature too, and BWXT expects that a ceramic and tungsten composite will allow for better operation at higher temperatures.

What's more, NERVA ran on 90 percent highly enriched uranium that would today qualify as weapons-grade. But because the fission process throws off more than enough heat, those levels are overkill, Patel said. BWXT's designs will harness material enriched to just below 20 percent On top of allowing safer reactors, the modest levels of fissionable material could open the door to more public-private partnerships.

I'm sure that got Elon Musk's attention. Scott Hall, a developer of one such electric propulsion prototype that recently broke records at the University of Michigan, says he'd love to see any of these technologies get into space, but doesn't think it'll happen soon.

But whether it takes one decade or 10, Houts thinks nuclear technology could transform space exploration. The systems beyond that could have extremely advanced capabilities," he said. Nuclear Engine for Rocket Vehicle Applications.

It used reactor fuel rods surrounded by a neutron reflector. Unfortunately its thrust to weight ratio is less than one, so no lift-offs with this rocket. The trouble was inadequate propellant mass flow, the result of trying to squeeze too much hydrogen through too few channels in the reactor. The 25 kilo-pounds-force 25 klb f "Pewee" solid-core nuclear thermal rocket was the smallest engine size tested during U. While small, a cluster of three is adequate for a typical Mars mission. Single engines were adequate for unmanned scientific interplanetary missions or small nuclear tugs.

One source suggested that each engine would require a 2, kg anti-radiation shadow shield to protect the crew 6. How Small is Big Enough? The scientists wanted to promote the development of a right-sized solid core nuclear thermal rocket that was as small as possible, but no smaller. The , N 25 klb r " Pewee-class " from the U. Project Rover was the smallest Rover engine.

They looked at a 33, Newton 7. There is a minimum amount of fissionable fuel for a reactor, or it just cannot support a chain reaction. But it was a bit too small to do anything useful, even in a cluster of three. About all it was good for was an unmanned robotic science mission. A 73, Newton It hit the goldilocks zone, it was just right. The engine uses a graphite composite core, because that allowed them to build on the expertise from the old NERVA program. One source suggested that each SNRE-class would require a 2, kg anti-radiation shadow shield to protect the crew six metric tons for a trio of SNREs , assuming an 80 meter separation between the engines and the habitat module.

Understanding your bird's anatomy and how it works may help you in hand feeding. Remember to go slow and watch your baby - he'll tell you what he needs air or more food. Count all pipettes, eye droppers or your C C. Check time of feeding and write it down, record when bird or birds have emptied out. This will aid you while hand feeding. It is important to know how many hours elapse before the bird will require the next feeding.

If you are consistent with your formula preparations you will know how much to feed the next time the baby is hungry. Formula intake may have to be adjusted up or down in CC. Good record keeping will help you on the way to a healthy baby. Furthermore it will alert you very quick of any problems you may have. One of the problems of hand feeding babies can be a slow crop a crop that does not empty out on time. Most breeders call this a sour crop or yeast infection.

There are several conditions that can be the cause of a slow crop. If you feed too much formula, reduce the formula intake somewhat at the next feeding. If this was the case the baby should empty out the next time normally. Some times a sour crop is a secondary problem to a much larger problem. If the problem of a slow crop persists, consult with a vet as soon as possible.

Your babies life may be in jeopardy. Most of all, remember that overfeeding will kill. Never feed babies until they are totally empty. A baby must always be empty at first feeding in the morning. This is one of your most important things to remember.

Do not kill your baby with kindness. Overfeeding can be deadly for your baby. As the baby grows it will require more food intake so you need to increase the amount of formula offered to the baby until it enters weaning stage. Repeat process when empty again. AGAIN do not feed any baby birds until crop is totally empty. I recommend babies be kept in a brooder or a heated aquarium at a minimum of 85F degrees.

Depending of the babies age the temperature should be between 85F and 92F for very small babies. If you do not have a heated aquarium, you can place the aquarium the babies are in on a heating pad. Make sure you have a thermometer placed in to the aquarium to maintain proper temperature so babies won't get too hot or too cold.

This is very important - if babies get too cold their digestive system will slow down, if they get to hot the will suffocate. Always maintain temperature consistency in the brooder or the aquarium whatever you use; it is very important.

Most of all remember you are holding your baby or babies live in your hands. Return to articles on hand-feeding of baby birds. Another project by WebMagik. That aside, allergies are genuinely a potentially serious problem and reactions to them are usually soon after exposure. It feels right to me, seems like less hassle, seems as if it puts less pressure on baby and parents and actually looks like it would be fun.

However, I am concerned as my son has reflux. I am brand new to this site, but saw your post and had to reply. My son is 7mo now and also has reflux. We have been shoving prilosec down his gullet since he was 1 week!

I started him on purees at about 5 months, when he started reaching for my food and making chewing motions when I was chewing. He did ok, still does, but not knowing that BLW was anything with a name or following! I started giving him bites of my soft food once he was starting to push the food around in his mouth more.

Since I started feeding him my food he has been keeping the food down better than ever, and eating more. Just today I sat down to eat a nectarine skin off!

And that was right after he nursed. I have had to be more careful with what he eats than it seems many BLW moms are, remembering to keep in mind his sensitive tummy. Keeping foods bland and avoiding food that can cause indigestion and gas. And since many reflux babies are also constipated bananas are right out too, at least for us. And since many raw foods are more irritating to a reflux-y tummy I am sure steam or microwave anything but the mildest of foods. In my experience with this sort of feeding my 5yr old was the same it is actually better for reflux babies since if a food makes their tummy upset, the just wont eat it.

My advice would be not to push it, wait till baby is showing signs that they are ready to start eating they will be just fine on breast milk or formula till they are ready and just make sure you are still careful what you give. If you are not concerned about dairy, it is a good time to introduce yogurt since it has probiotics that aid digestion.

We have allergies in the family so I have just started adding probiotics to his food. I have personally just looked up advice for eating with chronic reflux for adults and adapted that as I could. And no one knows your baby as good as you!

Just listen to the dear boys body and it will be fine! Hi, Im very interested in BLW for my first child.

So im wondering what would be a few good foods to start with that I know she can manage with no teeth..? So happy to find this site! For 2 who is now 6. Thanks for the site and info. This information is really useful, I have been EBF my 5.

I must admit I am very nervous, but excited at the same time…. Is there any one else on here who has BLW twins? She did this once when I gave her calpol too a while ago, and she just projectiles all her stomach contents up.

Is this normal, what should I do? I have just had my LO on my lap, she reached out for a bit of toast I was eating so let her have the crust. She got a little bit in the front of her mouth and was chewing, she then was sick again, heaved twice and her stomach contents up.

She is 6 months tomorrow but not sitting up on her own, is she just too young? I would probably just leave it for a week or two and then try again.

She is still little, she has loads of time to get the hang of it: Love this — I had never heard of BLW before, I have now brought this up with my ante-natal group all 4 months post natal and hopefully a few of us will have a go at this.

Sounds so much more natural than mushing up food… Really good website, nice one: Hi I just started BLW and it seems to be going well. I have tried pears, peaches, bread, cucumber,banana,and chicken breast….. Not all at one sitting though. I understand that this approach is more relaxed. I started with fruit.

Should I include all the food groups each time? How does it work.? Am I crazy for feeling this way? All babies have the gag reflex, all adults have it to, its just much further back for adults.

A babies gag reflex is very far forward in the middle of their tongue. When you see a BLW baby gag look at where the food is. This is still not choking.

Honestly we gagged and vomitted at most meals in the beginning but the more opportunities she was given to explore food the better she became at it. Practice is key to its success I think. My baby isnearly 6 months old, can sit in a highchair with a bit of extra support and is fascinated by our food. He was 1 month prem so hv said ideally should wait til 7 months to start weaning. Has anyone tried blw non mush before 6 months? He can drink from a sippy cup and has 2 teeth with another coming.

We started around 5. I started then with non-mushed veg and fruit. Broccolli and Carrots are great first foods! If your baby still needs support to sit up straight then it may be that they are not quite ready. Its important they can sit up straight to deal with the food in their mouth. What helped Sofia sit confidently was having her sit on my lap at mealtimes which encouraged her to sit without support. He is a very lively little one who is just SO keen to explore the world.

He has two razor sharp teeth that are part-way up. He is on the lean side 5th percentile for weight but has been since he was born, so I try not to stress. Also a few people have mentioned a cup noiby? I think you mean a doidy cup, made by biccipeg. Am sure you can get them on Amazon. The top is slanted so the baby can see the water coming towards them. Soon enough your little one will be eating plenty. The exciting thing is that number three is 6 months tomorrow so we get to do it again: What makes you think your daughter is interested in food?

Is it just curiosity in general? At that age babies are generally satisfied by being involved with spoons and plates to mess with. In fact, weaning before 17 weeks has been shown to significantly increase allergic reactions and gut problems, so be wary….

Actually rule about starting at 6 months is now on the way to being considered out of date. She said that there is no evidence to say that withholding allergens until after 6 months reduces allergy in fact they believe it may in fact be increasing the incidence of allergies.

She did not give a best age to start solids but she believed in getting babies accustomed to whatever the family will be eating. Personally I would think that if babies are able to put food in their mouths and show an interest in doing so it is probably nature telling us they are ready. There is not much comment here about experience introducing food between 4 and 6 months.

It just depends on the baby, Isla. Some start a bit earlier, some a bit later, just as with walking and other developmental milestones. Perhaps you can help.

See, I remember BLW as being: There was only one mantra: LY different food and it took me a while to get my head round that, because i was offering dd2 things that had been a hit with her sister and forgetting to give the misses a try as well.

And yes, I am totally making that same mistake i. I could go on for decades. Also kids on this diet sleep through the night much fater and are overall happier and healthier. Get the crap out, eat REAL food! Yes bread is processed! We have been practicing BLW for a month months of age. I loved the idea when I heard about it from another mom and read several books beforehand to prepare. In hindsight,I doubt she was choking in any of these instances, but I definitely turned her upside down and hit her back hard in two of the three instances.

One time she even vomited. She never stopped breathing or changed color. Probably in all of these circumstances, she could have worked it out on her own. It would be helpful to discern if what I experienced was normal. I am aware that my response to what happened was not necessary, so examples of how others handle similar situations would be immensely helpful!

I am terrified now!!!! Today, I cut up the food that I have previously been giving to her as a handle and I preloaded it on a spoon. How do I get back on the right track after being scared? Thank you so much for your time. For me reading the book etc gave me the confidence to let her get on with it. I never once needed to intervene. If your baby is coughing and spluttering to get the food out then they are dealing with it.

Honestly I think turning her upside down could make things worse and make her more scared. However in the meantime If she gags again then my advice would be to stay calm, and watch and see if she deals with it because 9 times out of 10 she will.

Only if you can see she is in difficulty then I would be trying to help. When you see your baby gag look at where the food is. To give you a description of gagging, my little boy will normally open his mouth, lean forward and stick his tongue out, whilst making a gagging type noise.

Do you eat at the same time as your daughter? I try to share mealtimes and make the mealtime a sociable time rather than sitting and watching the baby eat. Often the food then just gets spat out, I give him a drink of water, say good boy and let him carry on. Perhaps you just need to go back a couple of steps until you get your confidence back.

Good luck with it, hope you can get some useful advice on here. When Fraser first started weaning he gagged a lot. He would cough and sometimes be sick well, a bit of food would come back. Although I can be a bit of a panicker by nature for some reason I trusted the profess and my experience was by staying calm and giving Fraser the opportunity to sort it out himself, he was fine. He would start eating again straight away. The only time I thought hr might be choking was a few weeks back aged 14 months when there was a moment with a satsuma segment when he looked the same as normal gagging but with no noise.

I slapped him on the back and thd satsuma flew out. I have a 10 second rule. I sit on my hands for 10 seconds before doing anything. We have had a few incidents but he is now 9 months and its way better than before. Try eating at the table with her in her high chair and chatting to her as you eat. Make it a social occasion to take away your fears and distract her from feeling afraid.

My husband and I are both infant CPR certified, and we always share mealtimes. I eat breakfast and lunch with her and we all eat dinner together. I am sure that even the proper choking procedure scared her as she was not really choking!

In only once incident did a rather large piece of pear come up with quite a lot of vomit…In hindsight, I think she vomited because I tried to remove the pear, but probably pushed it further back.

Even when gagging, my daughter is very quite-she makes no gagging type noises, which increases my anxiety. I am making progress though-last night she slurped down a rather large hunk of cooked bell pepper from our stew. We handed her a piece large enough to fist with some extending to chew, but she bit the thing off! Personally, I kept eating and looking at my dish. I did not want to look at her with panic on my face.

My husband was saying things like stay calm and in your chair, she is not making noises but is still breathing…It was funny when she finally swallowed it.

I think that had I not exactly what happened last night would have happened, or instead of swallowing she might have worked the food out of her mouth. I like the 10 second rule!!!!! I hope that with continued experience and practice we will all get better. Again, thank you for your help. Jelly was a fun experience, oh how funny to watch Miss 10months trying to pick up jelly with her new found pincer grip. Which has developed so quickly due to BLW!! Well that is of course a huge point, but i would ask how you think that conventional weaning using puree for a while then letting them self-feed protects them from choking?

I also sterilise all of her feeding equipment plates, bowls, spoons — you name it! My Katie Siobhan is just about to turn 7 months on the 18th of Dec. Before reading about BLW I was doing the pureed baby food thing! I went to a friends home on Thanksgiving day and my Katie gleefully reached for my plate… first time ever! She happily ate spoon fed bits of mashed sweet potato casserole and fresh cranberry sauce. The next evening her bottom was bright red… I think the cranberry changed the PH in her urine and caused a reaction.

Will hold off on cranberries for a bit! As she is not sitting unassisted yet, she has to be held up in a high chair with padding around her. Thanks so much for the wonderful info. BTW I found your site from a poster on Babycenter. Forgive me if some one has already said this but I dont have time to read all the comments.

I like this approach however I would introduce new foods 1 at a time for allergies anc such. Also grains and dairy are much harder to digest and should be introduced LAST. Dairy months and grains 12 months. I personally will NOT feed my baby grains except perhaps rice until 12 months because my oldest and I have issues with gluten. The spaghetti suggestion made me cringe. This is an excellent article concerning feeding nourishing foods to growing babies.

However current advice in this country has it that gluten is fine for children over six months. What a fabulous resource this is! With my first, i almost changed my name by depoll to Anabel Karmel, so strictly did i follow her instructions. And it drove me mad and intact, having to go back to work at 6. I was aware of BLW, but my mother aka the harbinger of doom put me off it. I did wait, til a week before she was 6 mths old…and am now 3 weeks in.

And by gad, am amazed. However, got a bit carried away yesterday and gave her scrambled eggs, which she loved, but came up with a rash around her mouth. Anyway, just wondered what peoples thoughts are on what to do now. Or just back off? Had a mooch about and chat with the imminently sensible gals and guys on the forum.

Meanwhile, pitta and houmous a HUGE hit today…brilliant. My mother will have her wagging finger out at xmas if i turn up with a baby who only eats meat and potatoes. Am not one to cook different meals for different peeps….

It feels like a brik is falling from my shoulder i am sorry if my english is not as suppose too, i am dutch. The story is that i am trying my hardest to wean my youngest daughter who is now 9 months old.. My oldest was never a problem ate the plate with the food if she could.. My son has a major allergy to egg so i can understand th allergy thing people r worried about, but in my house there is no egg related food at all, we all eat the same food.

Her kids were weaned in the 70s, so all kinds of ages, the oldest being three months, so by six months we were all self-feeding anyway.

We have been doing well with fruit, we have had our first gag up with banana and guava and oddly enough this has mad me feel more confident to try more stuff when I get home lol: Ok so we have tried most stuff fruit, veg, meat, fish and eggs — no issues so far! How about cows milk? I apologise if this has been covered elsewhere also, is there a problem if I give him proper food and the odd puréed slop as its already been bought for me by someone else? I give my LO shredded wheat but just use enough milk to soften it.

Is she maintaining a line on the growth charts? Is there anything appearing in the nappies? Have you tried going back to any favourite foods? It did seem to make him more interested in the solids! My son is 5 months old tomorrow. When I was drinking water out of a glass 2 days ago, he reached up.

I put the glass to his mouth and tipped it a little and to my amazement he drank no problems. Also in the last 2 days he can now sit up un-aided, but after some time he leans right forward and needs propping up or lying down if he has had enough. So my question is! Can I start my son on some breakfast with us in the mornings when he is 5.

If so, what would you suggest I gave him to start with? Maybe I am just not imaginitive enough! I am just concerned about toast scratching his gums. He has been teething since 3 months. Also, what bread should I buy? Just a banana itself would be fine, let him mush it with his gums. I just buy normal wholemeal bread, have tried seeded batch which resulted in interesting nappies!

I waited until 6 months but my LO was sitting early so I did let him gnaw on the odd bit of steamed carrot, pear or banana. Started in earnest at 6 months though. Well this morning he didnt take much notice! So I am going to try hold out until 6 months anyways. I can get anything for him. Thing is I live in Dubai so a lot of our stuff is brought in from overseas! I guess we get some stuff local! This might sound a bit daft.

Just didnt think of carrots as a breakfast food? I just read why you dont give bread before 6 months, so that helped! I hope I get the hang of this! I just feel so nervous! Will get a high chair soon, so he gets used to it I guess? Have you tried sitting him at the table with a spoon and bowl or an empty cup to have a good bash? Yes defo gonna try that! I never bothered about breakfast foods, really.

Feel no obligation to let them load the spoon as well, though, that way madness and splattered curtains lie. I have found it really helpful while weaning my daughter. Lara, I thought you might find it useful to hear my experience. I think what has worked really well for my daughter though is because she is predominantly baby-led she knows when she has had enough and communicates that to me.

When I do feed her with a spoon I spend my time doing so and ensure I pick up her signals as to when she is full. I also ensure she always has her own spoon, otherwise she gets very frustrated and is constantly trying to grab mine! Interestingly this week I went for lunch with some other new mum friends of mine who are weaning their babies with purees and they were all really impressed with how well my daughter is eating and feeding herself she had a spinach and cheese muffin, some melon and salad.

We all had great fun waching their faces. On the waiting a few days between introduction of new foods rule, in NZ I have been advised to wait days between new foods on the basis that it allows you to pinpoint the cause of any reaction and conversely to introduce as many foods as you wish early on on the basis that it allegedly reduces fussiness later on.

We started on purees but the battle of the spoon soon made meal times frustrating, for both of us. We tried BLW and our little girl embraced it with great enthusiasm!

Now that she is feeding herself she is much happier at meal times. Feeding herself means she will try anything — lettuce, chard, beetroot, meat, fish, anything really. She is an eating machine!

It makes so much sense and it works. I just gave her some prunes and she was good to go. We started a bit early as she was sitting up and grabbing at our food.

How do you say no to a little one who is so interested. She has masted this talent and we are so happy with her progress. Hiya — i have just found out about the blw concept through mothering. This has been fine — he eats a variety of food with this method but does go up and down with his interest and i feel like sometimes hes not really that into it but just eating because im giving it to him, which is why i would really like to start the baby lead method — im just worried that because he has been eating quite a bit of solid food that he might loose this nutrition although he is still breastfeeding A LOT.

He mostly just plays with the food if i let him do it himself so doesnt really get much down. Im sure it will improve with time but just wanted to know your throughts on how to approach this initially??

I find with some of the finger food e. He wakes up several times a night seemingly wriggling around and sometimes results in bottom wind. I would have thought that fruit and veg is probably easier on their gut than grains and cereals though. You can still be baby-led in theory! Let him handle spoons and have a go at feeding himself, and try again with a wider variety of foods in a week or so to see how he fares.

He loves feeding himself with sticks of various items, but he really struggles then digesting it, in fact banana seems to make him really constipated. I gave up on them and reintroduced them when he was over a year old and doing proper stinky solid poos. He is now a few months off 5 and eats one or to a day with no issues. Both of mine took time to settle with the transition from a milk only diet to one involving solids.

I recommend moving his last meal forward a bit so he has digested most of it and got rid of the wind before he goes to sleep.

And remember you have no reason to be on 3 meals a day at 6. Hope the sleeping thing gets better for you, lack of sleep is the worst part for me. I would just like to apologise for the random apostrophe that seems to have crept into the bananas!!! My 6 month old became quite gassy at the introduction of foods and sounds just like yours! Thing is, I started with the cereals.

Then I added some purees and he became gassy. Went back to just brown rice cereal with breastmilk and he was worse than ever! Just pears, apples, carrots, and squash he reacted to sweet potatoes — diarrhea, rash, vomiting. I plan to cook up some pieces to allow him to play and self-feed in addition to the purees. He loves the pears and carrots — they seem to be treating his tummy better than the cereals. Every baby is different, but in our case we found simple purees worked better on our sensitive baby.

We used Happy Bellies brown rice cereal and oatmeal, by the way. The rice cereal is completely dairy and gluten free. Great stuff, but even better maybe would be to just let the babies self-feed altogether, and see if he expresses a preference himself? Have a look on youtube so you can see the difference between choking and gagging — choking is scary, where the baby stops moving, goes red or blue, stares and you end up having to turn them upside-down and whack them on the back to dislodge whatever is stuck in their throat and start them breathing again.

Choking is very rare. Much like if you stuck your fingers down your throat! It took around 3 weeks for the gag reflex to disappear for us, although it still happened from time to time usually somewhere super-inappropriate, like a smart restaurant! My son is 6 months and 1 week. When he was months old, he slept through a handful of times and was down to only waking once when EBF.

Now he wakes up several times a night and is co-sleeping so I can get some kip! He did manage to swallow some broccoli I saw it in the spit up , but he has a solid tongue-thrust reflex still bit off a bit of banana last night and it came straight back out since it was a thumbnail-sized chunk. Hi there, I am new here. I am starting my son on BLW as he is 6months. Anyone else have this problem?

Is he simply not ready? I appreciate that a lot of the fun for the kids is feeling squidgy things but some children are naturally more fastidious and take longer to get to grips with the mess.

Remember, until last week he had only ever had milk, maybe he reckons the toast is a big enough change for now? Well I have started! We have had cucumber, carrots gagged loads with them , banana and brocolli. Loved it all and he is feeding himself organic whole grain baby cereal last two mornings, well if he swallows much. Someone mentioned a 6 month growth spurt? My little one was sleeping 8: Last 8 nights he has fidgeted none stop and waking up 3 times between 8: I am exhausted, and every time he is just hungry.

He seems to have his bottle, nappy change and be burped all in his sleep. I just cannot seem to get any sleep! The thing is he is having formula, 2. He sometimes leaves some, so isnt hungry!

And my son was 9. Just ride it out? So can food help with this? I reckon maybe a more convenient for you, i mean dream feed might help with the sleeping, though. My DD used to do this and sometimes we had to tweak her routine a little bit to accommodate changes.

Thank you so much for all this info. I am excited to start this method at 6 months. Hopefully it will work.

Now, onto the research! My baby is 6 months old and we started introducing purees at 4 months. I am interested in starting baby led weaning but wanted to know if there is any harm in offering her purees twice a day while at daycare and pieces of food at dinner. I actually came across the concept of BLW when I was telling my sister in law that my daughter was interested in a banana I was eating so I let her have it and she bite off and chewed a few pieces with her single bottom tooth.

My only concern with doing both is will she be more likely to choke if she is learning to swallow food without chewing during two feedings, but then needs to know to chew when offered pieces of food at dinner? Hi, I started to wean my baby about 3 weeks ago, using puree, but have been giving her bits of toast etc i didnt realise that was blw!!!

We are starting BLW today, so I plan to give him his new food at lunch, but today is Saturday, so that is convenient. During the week, he has various grandparents watching him, so I would prefer to introduce new foods at dinner, which would be close to when he goes down 6: Do I really have to let the grandparents have all the fun of introducing new foods during the daytime?

I am in desperate need for some advice. I read BLW book and think it is wonderful. However, my son is already almost 13 months old and he is not taking to solids. My mother-in-law was taking care of him until now and spoon-feeding him pureed food, but she literally had to sing and dance to trick him into eating. Mealtimes were always a struggle. Now that she is finally gone home I am trying to teach him to eat solids BLW way, but he is having hard time eating anything but some commercially made cheese puffs and crackers.

He refuses to be spoon fed anymore, and he refuses to eat our food. I eat all my meals right in front of him, and sometimes he takes some of my food, but he would chew it and spit it out. But mostly he acts disinterested no matter how much variety we offer him.

He still drinks formula so he is not loosing weight, but I am very concerned — he cannot keep eating formula till he is 18 years old! Please help with some advice for parents who started BLW with toddlers and who are having difficult time.

Thank you so much in advance! Hi Itala, the thing about BLW is that really, it starts when weaning starts, so round about 6 months, so that opportunity has passed I think. I doubt you would have done the singing and dancing and tricking, left to your own devices. D And remember, short of force-feeding him there is Absolutely Nothing you can do about his reluctance. I know some babies love a picnic on the floor, or in the park, or even in their buggy, because they really dislike being observed.

I think mine waited until 8 months before refusing food, so your little girl is very advanced. Another trick I used is to eat exactly what he was eating and show it to him.

Eating on the floor always helps too! Now that it is summer, try picnicing in the garden on in the park — they seem to try things they never tried before when they think they are picking something from the ground! Also I think when she starts nursery she will see example of other children eating and will progress much quicker. Also a type of cup matters, I tried a lot of them, and the one he loves is Tommy Tippee essentials, so yours might prefer a certain type of cup too!

Thank you so much for your reply. Relaxing about it and just letting things proceed naturally is what I need!

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