Breakthrough In-Space Propulsion for Affordable Mars Missions

kbd512 · 2016-11-26 18:04:15

Ok, so let's run some new numbers using the new SLS core stage LH2 tank since that is the sort of thing we have to use right now. This time I'm going to ensure all figures have been converted to metric. I also made other mistakes on the average Isp of the NTR, which is 900s, and the average thrust and Isp of the SRB's, which I'll attempt to correct here (no guarantees).

~3.377 gallons of LH2 weighs 1kg

SLS LH2 Core Stage Tank
Volume (Propellant): 537,000 gallons
Mass (Propellant): 159,000 kg
Mass (Empty): 24,818 kg

STS Inter-Tank

Unfortunately, I don't have the mass of the SLS inter-tank structure.

Mass (Complete): 2,500kg

SNTP Pebble Bed Reactor
Mass (Est.): 10,000kg
Thrust (Avg.): 2,350kN
Isp (Avg.): 900s

ATK 5 Segment RSRM

All numbers converted from the 5 segment RSRM contained in "DataSheetSolidATK.pdf".

Mass (Empty): 85,598kg (some liner material is burned up, hence the higher empty weight than burnout weight)
Mass (Loaded): 734,601kg
Mass (Propellant): 649,003kg
Mass (Burnout): 82,491kg
Thrust (Avg.): 12,859kN
Isp (Avg.): 267s (derived from total impulse and propellant mass)

If we assume the same weight for the inter-tank structure as STS, which won't be the case, since no 12,409kg LOX tank loaded with 196,000kg of LOX is sitting on top of it, then the SLS LH2 tank, STS inter-tank structure, and NTR weigh a combined 37,318kg. Incidentally, the pebble-bed NTR weighs about as much as four RS-25's, but only produces one quarter as much thrust. However, the core stage is still 48,137kg lighter than the 85,455kg SLS core stage. I can't find good numbers for the SOFI that covers the LH2 tank, so the insulation mass has been omitted. I calculate the SOFI to weigh 2,967kg based on numbers I have from a NASA presentation which says that approximately 4,000lbs of SOFI covers 16,750sqft of area over the STS ET. NASA has been looking at using a polymer aerogel insulation that is substantially lighter than SOFI.

The GLOW (1,49,202kg for 2 RSRM's + 196,318kg NTR core stage + 84,000kg payload) for this NTR-powered vehicle is 1,749,520kg. That level of performance is substantially above what SLS Block IA is capable of and does not use an upper stage, composite SRM casings, or a composite core stage tank.

If the core stage tank is constructed from composites that reduce LH2 tank mass by 30%, then payload mass grows to between 91t and 105t, which is roughly the same as SLS Block IB cargo.

GW Johnson · 2016-11-27 17:15:15

Kbd512:

Do not presume SLS for your launch rocket. Use something far more likely to fly, like Falcon-Heavy. I think you will be shocked by the launch cost numbers, if for no other reason.

If you also give up direct shots to Mars, I think you will shocked by how cheap it really is, to assemble large items in LEO, and then send them to Mars from there. Take your blinders off. Mars is not an extension of Apollo, because of the very long mission times in space.

Your predilection to base everything you do off of NASA's SLS has blinded you to far better ways.

GW

SpaceNut · 2016-11-27 19:02:39

Here is the numbers and type of foam used on the Shuttle External Tank....

https://en.wikipedia.org/wiki/Space_Shu … ernal_tank
The thermal protection system weighs 4,823 lb (2,188 kg).
http://science.ksc.nasa.gov/shuttle/tec … ef/et.html
ET THERMAL PROTECTION SYSTEM
The ET thermal protection system consists of sprayed-on foam insulation and premolded ablator materials. The system also includes the use of phenolic thermal insulators to preclude air liquefaction. Thermal isolators are required for liquid hydrogen tank attachments to preclude the liquefaction of air-exposed metallic attachments and to reduce heat flow into the liquid hydrogen. The thermal protection system weighs 4,823 pounds.

http://dura-foam.com/resources/foam-roo … fuel-tank/
The external tank is covered by three types of spray foam:
1-polyurethane foam: BX-250
2-polyisocyanurate foam: NCFI 24-124; used on the hydrogen and liquid-oxygen tanks
3-another polyisocyanurate foam: NCFI 24-57; used on lower hydrogen tank dome

kbd512 · 2016-11-28 04:06:15

GW Johnson wrote:

Kbd512:
Do not presume SLS for your launch rocket. Use something far more likely to fly, like Falcon-Heavy. I think you will be shocked by the launch cost numbers, if for no other reason.
If you also give up direct shots to Mars, I think you will shocked by how cheap it really is, to assemble large items in LEO, and then send them to Mars from there. Take your blinders off. Mars is not an extension of Apollo, because of the very long mission times in space.
Your predilection to base everything you do off of NASA's SLS has blinded you to far better ways.
GW

GW,

I'd given up on direct shots to Mars a long time ago, but NASA hasn't.

If EMDrive only works as well as NASA's models predict it to work, and that model has been pretty accurate up to this point, then we can send astronauts to Mars using Falcon 9 rockets. Whether or not more powerful rockets become available in the future is a moot point if a 200kWe input produces the predicted thrust level. Big "if"? Yes, but the reward is too great not to do the test. For Mars exploration purposes, there won't be a requirement for more powerful rockets at that point and current technology rockets, capsules, and inflatables are more than adequate for the transit times and surface stays involved.

Assuming EMDrive works as advertised, send two astronauts to Mars, orbit Mars, and then come back to Earth within the window. Once we've proven that we can go there and come back, and presuming Falcon Heavy becomes available, deliver a BA-330 to Mars orbit. The Mars Orbital Station will be the astronauts' home away from home if there's ever an issue with coming back. A secondary propulsion module will be placed there for emergency use. From there, we land, say the words, and plant flags. Then the real work can begin.

SpaceNut · 2016-11-28 18:35:07

I would do the demostrator mission first unmanned as you have outlined for the essentuals with maybe a mini experiment of life without gravity onboard for the cycle. This would allow for a scaled testing of life support and other waste removal systems for the duration as well. Then repeat the test while producing artificial gravity at mars level with a follow up of something greater....This is about as cheap as we can get for the 3 mission that would not only prove out hardware systems but what it would take for humans to come back healthy....

SpaceNut · 2016-12-12 22:40:23

Space Warp Dynamics The Latest Experiments and News

Its looking like when we create a space bubble and we use an EM-Drive we would be in a star ship....

kbd512 · 2016-12-13 12:28:46

EMDrive really needs serious funding ASAP. 1N/kWe is not some sort of experimental error. Something other than experimental error is happening and we really need to figure it out what it is. The implications for space travel are nothing short of a full-on revolution.

Our understanding of electrical and magnetic control systems will be to 21st century space flight what our understanding of mechanical control systems was to 20th century space flight. I still can't believe we have people tinkering in their garages to advance our understanding of physics because most of our so-called physicists are too busy maintaining a perfect echo chamber of self-reinforcing delusion about their understanding of electromagnetic phenomena.

Terraformer · 2016-12-13 17:04:30

As far as I know, they haven't demonstrated such thrusts, only predicted them. That isn't proof.

JoshNH4H · 2016-12-14 09:18:51

When did we get so many users who were cold fusionists and perpetual motionists?

Antius · 2016-12-14 18:18:22

JoshNH4H wrote:

When did we get so many users who were cold fusionists and perpetual motionists?

In the immortal words of Fox Mulder 'I wanted to believe'. We would all like to believe that there exists a magic bullet that will allow us to transcend the limitations of the physics that we know. People could travel to Mars in something not unlike an airliner. When that cubesat has been in orbit for a few months, the question will be answered one way or another.

SpaceNut · 2016-12-14 18:52:34

We know that anti-matter exists, Dark matter and these both do not fit into thermal dynamic so are there other things that we can not totally explain?

Void · 2016-12-14 19:21:10

I'm a bit light weight for this, but to that degree I support you Spacenut. There is just too much territory not properly mapped to connect to the historical dogma's.

No unifying theory. Got to be some weird and maybe useful stuff in the cracks somewhere. We just don't know.

I would say that the variance in the tests on Earth does suggest that some type of error is happening to different degrees in each test, but it could also indicate a process that "we" don't understand. A process where the results are different per the individual situation of testing.

Finding out is going to require testing and irritating pain.

Also never forget that there are people on this Earth who fear and hate technological people. They are slave masters, and only see other people as their potential property.

So, be concerned that the test results might be purposely tainted.

Conspiracy? Of course, it has always been there. We have always only been potential servants.

Last edited by Void (2016-12-14 19:22:14)

kbd512 · 2016-12-14 21:59:33

Void,

This is about the closest thing I've seen to a unifying theory:

https://ia902502.us.archive.org/31/item … 1small.pdf

Last edited by kbd512 (2016-12-14 22:47:33)

SpaceNut · 2020-06-28 18:15:02

just another NTR versus pebble reactor use

Mars_B4_Moon · 2022-05-30 06:28:41

Rapid Magnetic Explosions in Space: Explaining Mystery Behind Fast Magnetic Reconnection

https://scitechdaily.com/rapid-magnetic … onnection/

Project Timberwind aimed to develop Ronald Reagan era nuclear thermal rockets funding coming from the Strategic Defense Initiative ColdWar era "Star Wars" the US SNTP program was terminated in January 1994, after $200 million was spent on study and design and talk concepts. Russians proposed TEM nuclear propulsion aka "transport and energy module, it was a Russian Space Tug for nuclear electric rocket spaceship for Solar system exploration. The first reactor tests were going to be called 'Zeus' and envisioned to operate for 50 months and deliver payloads to the Moon, Venus, and Jupiter through multiple gravity assists, it would have Coolant: 78% helium/22% xenon, emit Heat power: 3.8 MW and Thrust of 18 N Specific impulse of 7000 s however with sanctions and the costly war in Ukraine this mission might never fly. For new Nuclear Electric Rockets exotic technologies have also been proposed: pyroelectric, thermoelectric with graphene-based thermal power conversion, thermophotovoltaic, thermionic and magnetohydrodynamic type thermoelectric materials. AIMStar was a proposed almost scifi like spaceship an antimatter-catalyzed nuclear pulse propulsion craft that uses clouds of antiprotons to initiate fission and fusion within fuel pellets while its magnetic nozzle derives force of motion from the resulting explosions
PDF here
https://web.archive.org/web/20140616201 … tar_99.pdf

Hall Effect Thrusters
https://beyondnerva.com/electric-propul … thrusters/

The majority of NASA’s research into Hall thrusters is currently focused on the Advanced Electric Propulsion System, or AEPS. This is a solar electric propulsion system which encompasses the power generation and conditioning equipment, as well as a 14 kW SPT thruster known as HERMeS, or the Hall Effect Rocket with Magnetic Shielding. Originally meant to be the primary propulsion unit for the Asteroid Redirect Mission, the AEPS is currently planned for the Power and Propulsion Element (PPE) for the Gateway platform (formerly Lunar Gateway and LOP-G) around the Moon. Since the power and conditioning equipment would be different for a nuclear electric mission, though, our focus will be on the HERMeS thruster itself.

HET the plasma itself would create electrostatic charge through the Hall effect, discovered in the 1870s by Edwin Hall.

Some other Hall Effect Thruster propellants of mightinclude argon, bismuth, iodine, magnesium, zinc and adamantane.

Last edited by Mars_B4_Moon (2022-05-30 06:30:19)

Mars_B4_Moon · 2022-09-13 15:35:51

I think a true Breakthrough might happen now that NASA and Chinese are looking to put nuclear reactors in space.

Mars_B4_Moon · 2023-04-02 11:52:03

Too many threads with 'Water' in them I will post this news here for the moment

'Pale Blue Successfully Operates its Water-Based Propulsion System in Orbit'

https://www.universetoday.com/160781/pa … -in-orbit/

SpaceNut · 2023-04-02 14:55:16

Not a choice when the water is crew required not only for shielding but for all other things....

Mars_B4_Moon · 2023-05-09 07:10:54

Momentus tug raises orbit with water-fueled thruster

https://spacenews.com/momentus-tug-rais … -thruster/

So the reason I add this in the 'breakthrough' is it is a Space Tug and sometimes when new mars users have talked with Chatbots they have suggested updating old tech like 'Solar Sails'

A Water rocket could be useful as a train launch on the Moon or sending product from a Base on Asteroids and transporting material to Mars.

A hybrid form of propulsion could also be used.
I think there were threads which discussed using water-fueled thruster but I will post the news here for now.

SpaceNut wrote:

Not a choice when the water is crew required not only for shielding but for all other things....

It also seem to exist in plenty in places like Europa and Comets.

Last edited by Mars_B4_Moon (2023-05-09 07:12:53)

Calliban · 2023-05-09 12:29:23

For interplanetary ships, an open cycle gas core fission rocket can avoid issues of radioactive contamination if it remains outside of Earths magnetosphere. Earth's magnetotail is 60 Earth radii long - a little under the Earth - moon distance.
https://www.nasa.gov/magnetosphere

Mars and Venus have no magnetic field and exhaust velocity exceeds escape velocity. Jupiter has a formidible magnetic field, but any radioactive ions trapped within it will spiral down the field lines into the Jovian atmosphere.

Mars_B4_Moon · 2023-08-04 12:18:13

NASA and DARPA Tap Lockheed Martin for a Nuclear Propulsion Demonstration
https://gizmodo.com/nasa-darpa-lockheed … 1850682737

There seem to be many other new ideas coming in the next few years for operation on the surface of the Planets, the Chinese now look at hopping robots maybe from some social media comments it could work like a Rabbit or Kangaroo. For surface operation it seems to make sense if coming out of a valley or large crater with slope gradual incline, on the Moon Astronauts found it easier to hop so maybe Robots can be doing the same hopping motion offworld. The news items online reported the Chinese lunar base will include a rover powered by nuclear energy with a hopper and communicate with an orbiter. I have seen some US and British concepts with propulsion, a vertical takeoff, vertical landing (VTVL) vehicle which would be called a 'Hopper' I believe University of Southampton but the vehicle flies and did not actually hop as an animal or human does.

Back in 2018 NASA had an article about a Hopper for Exploration of the Neptune Moon

Triton Hopper: Exploring Neptune's Captured Kuiper Belt Object
https://www.nasa.gov/directorates/space … on_Hopper/

Mars_B4_Moon · 2023-09-30 08:20:13

Tahanson's latest talks with the AI Chatbot it seems to think Magnetoplasmadynamic thruster might work on the deign for the 'Large Ship' sometimes referred to as Lorentz Force Accelerator

exhaust velocity 15–60 kilometers per second, thrust 2.5–25 newtons and efficiency 40–60 percent, additional research has shown that exhaust velocities can exceed 100 kilometers per second.

https://web.archive.org/web/20161018201 … sciam-2009

tahanson43206 · 2023-09-30 09:32:32

For Mars_B4_Moon re #72

Thank you for noting the recent conversation with ChatGPT4 about propulsion for Large Ship.

Here is a link to a very interesting follow up ... ISP appears to reach 820, and thrust is (on the order of) 8,000 Newtons.

Corrected from 86,000 Newtons 2023/09/30 at 16:14 local time.

https://docs.google.com/document/d/1w9n … sp=sharing

(th)

GW Johnson · 2023-09-30 10:23:52

For most destinations, electric propulsion is fine, and has the high Isp needed to limit propellant requirements to something "reasonable" for interplanetary travel. It's just very low propulsive device thrust/weight, and exceedingly-low vehicle thrust/weight. The burns are definitely not impulsive, so you ought to double your theoretical dV values for sizing vehicles. The Isp is high enough to render it attractive, despite doubling the dV's.

The problem is Earth departures and arrivals, because it takes months to spiral in or spiral out, through the Van Allen belts, which exposes (for months at a time) the craft to radiation levels comparable to a large, lethal solar flare event, or to a 10-50 kiloton fission ground burst close by. We're talking 50+ REM per hour! Maybe a big plus!

You need something else to propel you quickly through the Van Allen belts. Apollo did it by taking under an hour to traverse them. You cannot accelerate that fast with electric. You will need something else to escape through the belts, or to capture through them.

GW

Last edited by GW Johnson (2023-09-30 10:26:58)

tahanson43206 · 2023-09-30 10:54:57

For GW Johnson re #74

Thanks for your continuing interest in "advanced" propulsion.

Here is a reminder for folks who might not be following SpinLaunch closely:

Per Google's enhanced search:

Generative AI is experimental. Info quality may vary.
The Orbital Accelerator from SpinLaunch spins a launch vehicle up to 5,000 mph (8,100 kph) before releasing it into the atmosphere. The system uses a vacuum-sealed centrifuge to spin the rocket. The rocket then ignites its engines at an altitude of roughly 200,000 ft (60 km) to reach an orbital speed of 17,150 mph (27,600 km/h).
SpinLaunch has conducted tests over 6x the speed of sound. The projectile experiences g-forces of around 10,000 times the force of gravity when it is being spun up. This is enough to tear the skin and muscle off a human being.
SpinLaunch - Wikipedia
Wikipedia
SpinLaunch FAQ
SpinLaunch
Not rocket science: SpinLaunch hurls payloads into orbit - Big Think
Jan 27, 2022
bigthink.com
Will physics prevent SpinLaunch from succeeding? - Big Think
Nov 17, 2022
Big Think
SpinLaunch And The History Of Hurling Stuff Into Space
Jun 24, 2022
Hackaday
Ask a follow up
How high has SpinLaunch gone?
What disadvantages does the SpinLaunch accelerator have?
Can SpinLaunch reach space?
The technology uses a vacuum-sealed centrifuge to spin a rocket and then hurl it to space at up to 4,700 mph (7,500 km/h; 2.1 km/s). The rocket then ignites its engines at an altitude of roughly 200,000 ft (60 km) to reach orbital speed of 17,150 mph (27,600 km/h; 7.666 km/s) with a payload of up to 200kg.
SpinLaunch - Wikipedia

SpinLaunch is a proven technology. It delivers a velocity of (on the order of) 5000 mph at release, and the mass released is multiple kilograms.

ChatGPT(4) has calculated an ISP of 820 for a centrifuge launch system that delivers mass at 5000 mph.

Let's leave chemical and even crude nuclear propulsion behind. The centrifuge was invented in the 19th Century.

Quote from Google:

1864
In 1864, Antonin Prandtl proposed the idea of a dairy centrifuge to separate cream from milk. The idea was subsequently put into practice by his brother, Alexander Prandtl, who made improvements to his brother's design, and exhibited a working butterfat extraction machine in 1875.
Centrifuge - Wikipedia

For Mars_B4_Moon ... please see if you can find the fastest (most rpm) centrifuge with the longest spin arm (in cm) and the greatest sample size (in grams).

I asked the search engines but got too much data back to be useful.

I'd like to be able to offer GW Johnson at least 1000 ISP and preferably far more, for his propulsion system for Large Ship.

(th)

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#51 2016-11-26 18:04:15

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#52 2016-11-27 17:15:15

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#53 2016-11-27 19:02:39

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#54 2016-11-28 04:06:15

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#55 2016-11-28 18:35:07

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#56 2016-12-12 22:40:23

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#57 2016-12-13 12:28:46

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#58 2016-12-13 17:04:30

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#59 2016-12-14 09:18:51

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#60 2016-12-14 18:18:22

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#61 2016-12-14 18:52:34

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#62 2016-12-14 19:21:10

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#63 2016-12-14 21:59:33

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#64 2020-06-28 18:15:02

Re: Breakthrough In-Space Propulsion for Affordable Mars Missions

#65 2022-05-30 06:28:41

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#66 2022-09-13 15:35:51

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#67 2023-04-02 11:52:03

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#68 2023-04-02 14:55:16

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#69 2023-05-09 07:10:54

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#70 2023-05-09 12:29:23

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#71 2023-08-04 12:18:13

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#72 2023-09-30 08:20:13

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#73 2023-09-30 09:32:32

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#74 2023-09-30 10:23:52

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#75 2023-09-30 10:54:57

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