How NASA Is Reinventing Space Travel

a portion of this video is sponsored by m Globe this blue glow is the emission of ionized xenon gas particles as they are accelerated to 10 of thousands of m/s out of the back of NASA's most powerful ion engine they have ever tested at technology they are aiming to deploy on the upcoming Luna gateway mission to keep the space station in orbit around the Moon starting as early as 2025 but how's this technology actually work and could it open a new chapter in man exploration of Deep space let's dive in to find out the idea of the iron engine was first introduced into literature by Constantin tski in 1911 and similarly popularized around the same time by the legendary Robert Godard the basic principle behind iron engines is reasonably simple and there are two primary categories of electric propulsion engine worth explaining grided iron propulsion engines and hall effect thrusters grided iron engines work by creating a strong electric field between two oppositely charged grids they ionize a propellant usually an inert gas like Xenon by firing electrons at it which when ionized is then attracted to the grid and once inside the electric field is accelerated to high speeds typically tens of km/ second out of the back of the engine so that the charged ion isn't then hall effect thrusters by comparison use a pretty similar mechanism ionizing accelerating and inert gas however ionization is achieved by trapping electrons in a high strength magnetic field which is then bombarded into the gas to ionize it these ions are accelerated out of the Thruster by the electric field that is produced perpendicular to the magnetic field that's applied hence the name the hall effect Thruster cuz applied magnetic fields induce perpendicular electric Fields there are a number of choices of propellant but most systems seem to use xenon gas because of its high atomic mass which makes it more efficient for producing thrust in ion engines when ioniz and accelerated heavier ions like Xenon in part more momentum compared to lighter ions making the engine overall more efficient Xenon is also relatively easy to ionize and it's able gas meaning that it's chemically inert making it safe to handle and also reducing risk of it damaging the internal engine components however Xenon does have some downsides it's rare and it's difficult to capture and as as a result it's reasonably expensive meaning the use of xenon in large quantities for numerous space missions could lead to Future supply issues there are a number of alternative propellants currently under consideration Krypton is another noble gas that is less expensive and more abundant than Xenon while it's not as efficient due to its lower atomic mass it is being considered as a more costeffective alternative for some missions argon is more abundant still but it also has a low atomic mass it has been used in some iron engines already like those on the dawn spacecraft and was recently deployed on spacex's starlink version 2 satellite Network iodine is an interesting emerging alternative with several advantages it is a higher storage density than Xenon because it can be stored as a solid and sublimates directly into a gas meaning that it doesn't go through a liquid phase which simplifies storage and handling its atomic mass is also very favorable for ION propulsion but why are iron engines interesting if they can't be used to actually launch spacecraft to understand that we need to look at a thorn in the side of all rocket scientists the rocket equation and here I'd like to thank today's sponsor M Globe for providing us a way nicer prop than we could ever produce MOA also has 40 other designs with some that feature Graphics provided by NASA and JPL and include planets moons asteroids and constellations watch as it slowly rotates in ambient light conditions without batteries or cables thanks to an internal solar powered motor that pushes against Earth's magnetic field ooh follow the link in the description to get 10% off a 6 in or 8.5 5 in M globe with the code bm10 thanks M now back to the video in order for a rocket to change its velocity the only mechanism available to do this with no air to push against by firing mass in One Direction by Newton's third law the rocket will experience an equal and opposite force in the other direction causing it to accelerate the equation for how this ejected mass and the speed it is ejected away at actually affects the rocket is expressed in the rocket equation here Delta V is the change in the velocity of the rocket V is the effective exhaust velocity essentially the speed at which the propellant leaves the rocket m0 is the initial total mass including the propellant here sometimes called the wet mass and MF is the final total mass or dry Mass once all the propellant has been used literally rocket science large accelerations can either be achieved by accelerating Mass to high exhaust velocities or equivalently by ejecting large amounts of mass chemical Rockets have low exhaust velocities around 2,500 to 4,500 m/s but they can move a huge amount of mass in a very short amount of time giving them large thrusts at the expense of requiring high mass of propellant this makes them incredibly effective for escaping Earth's gravitational pull where ion engines win however is in the effective exhaust velocity of the propellant ion engines have significantly higher exhaust velocities typically 15,000 to up to 50,000 I've seen in some instances meters per second which means that for the same amount of propellant they can achieve much higher final rocket speeds meaning a more fuel efficient overall operation where chemical Rockets produce a large amount of thrust in a very short time allowing you to overcome Earth's gravity iron engines produce a very small amount of thrust over a very long amount of time resulting in a gradual but a sustained acceleration to ultimately much higher speeds to put the amount of that thrust in context it's typically equivalent to a few grams of force so it's like a small mouth is pushing you through space but in the absence of air resistance a small Mouse force over a long time adds up this means that iron engines are less suitable for launch but highly advantageous for long duration space travel once in orbit or in deep space and typically how we see them applied due to their specific design parameters is that whole effect thrusters typically find application in orbit adjustment and station keeping for satellites as they have a slightly lower specific impulse or efficiency than grided ion engin which find much better application in things like the deep space one probe launched by NASA in 1998 and currently traveling an estimated velocity of 725 m/s or about 1,600 mph so that's the general background of iron engines but what specifically has NASA been currently testing and how much better is it than that previous system the advanced electric propulsion system or Apes currently under under development by NASA is a hall effect Thruster using xenon gas powered by a solar array and speced at 12 Kow a lot of those pieces we are now familiar with what is New Territory is the power of that system is two to three times more powerful than any other hall effect Thruster in production depending on exactly which source you read these typically usually clock in at only 3.5 to 4.5 KW I'm not sure if Apes is exactly how you say it but I like the idea that the Apes came up with it so I'm going to call it the Apes system from now on the Apes system was originally developed in 2015 when it was being designed to propel the arm mission to fetch rocks from nearby asteroids when arm was ultimately canceled Apes became the Cornerstone of the upcoming Luna Gateway missions where its power output should allow it to work as a primary proportion method in these sorts of large deep space and cargo missions this first round of testing was a qualification test for the very first engine the second engine will be delivered for qualification testing in around 2024 and is planned to operate at thrust levels equivalent to keeping the Gateway station in orbit around the moon during which the engine will be tested under long-term loads that it would be expected to experience in operation on board Gateway it will have fuel tanks of xenon fuel that will contain about 2 tons of material on each tank with three tanks total this should be enough for 15 years of operation but they are also aiming to be on orbit refu to extend the mission lifetime as needed at the moment the level of deeper information we have about how and why these engines are so much more powerful is reasonably thin on the ground but NASA is conducting these initial qualification tests for the Apes at its Research Center in Cleveland and once the individual Apes thrusters are validated three strings will be mounted onto the power and propulsion element the PPE that forms the core of the lunar Gateway the module is scheduled to be launched into space on November 2025 on a space X Falcon heavy rocket the engines will be powered by the station's 60 KW solar panel system one of the primary functions of the the iron engines on the PPE will be to maintain the gateway's orbit around the moon and adjust its trajectory as needed the ultimate purpose of Gateway will be to function as a small human tended space station in lunar orbit providing extensive capabilities to support NASA's emus Campaign which aims to return humans to the moon and eventually send them to Mars the job of the ion engine is made slightly easier here by the choice of gateway's planned orbit around the Moon which be a near rectal linear Halo orbit in simple terms this is a very elongated elliptical orbit that takes around 7 days to complete a full cycle at the perige or closest point the Gateway will be around 930 Mi above the Moon giving it easy access to the moon's surface then at apog or the furthest point of orbit it will be around 43,500 Mi away from the Moon the orbital path that it's choosing also maintains a constant line of sight with the Earth meaning that there will be hopefully no communication blackout periods and this particular orbit uses a balancing point between the gravity of Earth and the gravity of the moon and makes for an extremely stable path that won't require much energy from the PPE thrusters section further extending the serviceable lifetime and reducing requirements on their fuel reserves here in particular the comparatively low weight of fuel should be sufficient to support 15 years worth of continuous operation this is really where the iron engine comes into its own it's not perfect in every application but it really seems to be starting to operate at a level necessary to support use cases we only previous imagined Beyond servicing Gateway NASA has planned to extend these iron engine capabilities into future human Mars class missions in a 2017 conference paper the authors State pretty exacting targets for their specific impulse and weight to thrust ratios and list in a few documents I found a repeated mention of using these iron engines for regular transport of cargo and supplies between Earth and colonies or outposts on the Moon Mars or other celestial bodies where their efficiency makes them suitable for these repetitive Long Haul missions and interestingly also indicating that NASA and other groups really are aligning in their thinking around Technologies for viable off-world colonies I'll leave a few of these documents in the description if you're interested in Reading More all that to say we needed a technology to fill a gap to support deeper space exploration without the associated weight or limited lifetime of traditional chemical propellants and the ion engine may be the technology that starts opening up space exploration as a real possibility

Channel: Dr Ben Miles

Views: 46,633

Keywords: science, future, breakthrough

Id: b4QQ0bYyjME

Length: 11min 34sec (694 seconds)

Published: Mon Nov 20 2023