Getting to Mars with REAL technology, & what's currently missing.

Oldfart1939 · 2018-08-07 05:13:52

SpaceNut-

Please note that my reconfigured vehicle does NOT use the 8 Draco thrusters to land. I'm proposing a new, hypergolic fueled motor in gimbals for landing thrust.. The fuel capacity would be roughly 5x-7x the Crew Dragon version. I'm nowhere near my notes from this proposal I ran about a year and half ago. Will be back in the States in about 3 weeks. Will complete my thoughts then.

SpaceNut · 2018-08-07 17:04:02

No worries for replying anytime soon.
I was looking at the superDraco's for launch escape use for not only earth return landing but also for a mars escape if it should not make orbit as they might be possible to fire them to try to get to orbit or to allow for a return to the base. This gives a chance under either risk of failure modes.
Still looking for the straight down facing engine versus the canted protect by the shield air stream answer for the mars lander design. The first stage of the falcon seems to answer but the speed is much slower than what we would see on mars unless we have fuel to burn earlier than normal when we come out of the heat shield mode to where parachutes speed would open.

kbd512 · 2018-08-07 18:56:06

SpaceNut,

I still think the SkyCrane / tractor design that places the payload on the bottom is the best way to do this. It minimizes the mass of the landing gear, mitigates issues with egress in the case of a habitat module, and minimizes the need for cranes for surface cargo offloading. The LEM system worked well because the lunar environment is very low gravity and there was sufficient storage space in the lander stage for the limited scientific experiment equipment. Now people want to do something entirely different and are still trying to come up with ways to make the LEM propulsion system work at far greater scale. It's not that it can't work, it's just not a very mass efficient way to do things and mass is at an extreme premium for a Mars mission.

SpaceNut · 2018-08-07 20:16:28

So could we up scale the skycrane to being the return to orbit with the super draco's doing the landing keeping the craft to a very small package. The system would land with the skycrane empty and then refuel on landing from the cargo landers. Another option is to use a drop tank design to rid the mass on the way up to orbit. Tanks could come from cargo landers to make the launch vehicle.

So sky scrane at the top, followed by the habitat section (small cygnus) then dragon capsule for 2. and landing legs...

So cygnus is cargo hold on return to orbit and is used for living space for the return. Once on orbit the sky crane is sent off so that we can mate up with the orbiting earth return booster with supplies for return home.

So we would boost from earth an eds plus the mars crew unit on a falcon heavy with a second heavy launching 2 cygnus less booster stage (only solar panels) full of supplies with return from mars stage once we mate up in orbit.

SpaceNut · 2019-01-05 21:28:33

Russia continues work on plasma engine for superfast space travel aimed at successfully harnessing the power of thermonuclear plasma for use in a rocket engine. With a temperature of 100,000 degrees to form the plasma, and reaching a sufficient density to provide them with data suitable for further work on the creation of a plasma-based rocket engine

SpaceNut · 2019-02-12 20:57:14

Not sure if Nasa is getting serious or just pretending to kick the can down the road.
Developing a flight strategy to land heavier vehicles on Mars

The heaviest vehicle to successfully land on Mars is the Curiosity Rover at 1 metric ton, about 2,200 pounds. Sending more ambitious robotic missions to the surface of Mars, and eventually humans, will require landed payload masses in the 5- to 20-ton range. To do that, we need to figure out how to land more mass. That was the goal of a recent study.
Normally, when a vehicle enters the Mars atmosphere at hypersonic speeds of about Mach 30,

After mach 3 firing engines to create a more horizontal flight to aid in slowing the vehicle down...

research paper

SpaceNut · 2019-03-09 06:32:24

Not fo void but for the topic

kbd512 wrote:

Void,
NASA has determined that pound-for-pound, the best defense against SPE's and GCR's would be a woven BNNT fabric or composite. They're trying to determine how to use it as a structural material to save weight, because it's also very strong and light, but a woven blanket or mat of the material is also suitable for shielding purposes. I've already posted docs for this in another thread dedicated to radiation shielding.
The AFRL has determined that aerographite would also be good shielding material against electromagnetic radiation, though probably not against SPE's and GCR's. It's one of the lightest structural foam materials known to man, lighter than structural aerogel foam, much stronger than aerogel, and far more compressible without cracking or permanent deformation.
Physical Properties of 3D Interconnected Graphite Networks - Aerographite
Water would be great, but it's too heavy for space applications. We'd still need lots of it for other purposes, but probably can't deliver enough to use it as passive radiation shielding. I think NASA determined that they'd need 2m or more to keep radiation dose rates within currently allowable limits.

Nice to see food for thought on how to solve mass versus exposure.

GW Johnson · 2019-03-09 14:30:45

Most of the propellants we use should have radiation-shielding properties at least crudely similar to water.

Why not just hide behind the propellant you are going to use for the arrival burn?

This would be particularly convenient for an orbit-to-orbit spaceship design that has a significant arrival burn in order to enter Mars orbit, instead of a direct landing with nearly all aerodynamic braking.

GW

Void · 2019-03-09 14:43:13

I like it sir.

SpaceNut · 2019-03-09 22:37:39

Here is the measurements for a water barrel approach to having the habitat inside them.
https://space.stackexchange.com/questio … hielding-i

Let's say that the Mars vehicle that will get them there and back is a cylinder roughly 3.5m by 20m (same as was used for the MARS-500 experiments; that is a very small tin can in which to spend 3 1/2 years with 4 or 5 other people). With 1m of shielding water around all surfaces of that cylinder, the outer hull would be about 5.5m by 22m.
The volume of shielding water needed is the difference between those two cylinders, or $22\cdot\pi\cdot2.75^2 - 20\cdot\pi\cdot1.75^2 \approx 522.68 - 192.42 = 330.26 m^3$. As one cubic meter of water weighs 1 metric ton (1,000kg), that's 330,260kg to get into space.
Each 7cm (http://www.nist.gov/pml/data/xraycoef/index.cfm) of water divides the radiation by a factor of 2. Thus the total required is 38 * 7cm or 266 cm. Use 300 cm / 3 meters to make calculation easier and it provides an extra safety margin which makes the calculation easier.

https://www.nasa.gov/feature/goddard/re … n-on-mars/

https://www.quora.com/How-much-thicknes … -colonists

It has been determined that 16 feet (5 meters) of Martian soil would be needed to provide the same level of protection against solar radiation as the Earth's atmosphere does.
This number, however, is at least in part determined based on the water and/or hydrogen content in the Martian soil (hydrogen acts as good shielding against radiation). Just a few inches of water can have the same effect as 16 feet of Martian soil.

Looks to me like we are going to need a different means to build up the ship for long term use for the journey as well as for Mars surface life....

SpaceNut · 2019-04-05 16:38:51

Someday we will need to do better than this

kbd512 · 2019-04-05 17:21:56

SpaceNut,

If we use hybrid electric propulsion, then we don't need absurd quantities of fuel to establish a stable orbit. We can still use chemical rockets to break orbit at Earth or place the transfer vehicle into a highly elliptical orbit. After we're on our merry way, then we may as well use a cruise propulsion system. GW can relate to this as a cruise missile with a solid rocket booster. The booster blasts the missile out of its launch tube and into the air, whereupon the much lower thrust turbojet engine takes over.

SpaceNut · 2019-07-04 08:55:44

Scientists are working on artificial gravity that won't make you barf

One of the most convenient ways to create artificial gravity is to spin people around in a centrifuge. NASA and the European Space Agency have been testing this concept on Earth-bound volunteers. If that sounds stomach-turning, that's because it is. Motion sickness is a serious problem.
The Colorado team envisions future astronauts heading into an artificial-gravity room to spend time on a small revolving system with the aim of counteracting the negative effects of weightlessness. But they don't want space travelers to get sick in the process.
The scientists are developing a way to deal with a symptom called "cross-coupled illusion" that happens when you spin a person around and that person turns her head. The inner ear essentially has a freak-out, triggering a falling sensation and motion sickness.
The team spun a group of volunteers on a centrifuge in an upright seated position, but started each off incredibly slowly, at a rate of just one rotation per minute. Once the person acclimated, the researchers were able to increase rotations a little at a time until they got the volunteers spinning comfortably at an average of 17 rotations per minute, an impressive performance.

GW Johnson · 2019-07-04 09:35:51

We've known for a long time that unacclimatized folks can tolerate 3-4 rpm spin rates without too much in the way of symptoms. This stuff dates back to the Von Braun group's original wheel space station concept from about 1937. Something he publicized here in the US in the 1950's.

Acceleration is R w^2, where R is the spin radius and w is the spin rate. At 4 rpm, your spin radius is just about 50 m to generate 1 full gee. That implies a big structure for most concepts. At 3 rpm, it's even worse at about 89 m. Those were really big wheel space station designs, too. Something like 100-200 m diameter.

If you do that with a spaceship of any reasonable size, you need to spin end-over-end, like a baton (the other stable mode of spin). Otherwise, you cannot afford to build the thing. Or else, you have to develop idiot-proof solutions for the difficult transient dynamics of cable-connected systems. Rigid body spin dynamics is already well-known and well-developed.

At 17 rpm, spin radius for 1 gee is only about 2.8 m. That's small enough to spin your spaceship about its long axis like a rifle bullet. Which is a whole lot easier to do than trying to build centrifuges within spaceships. Nice prospect, if it really works without symptoms. We don't really know for sure, yet.

But, you need not wait to see if it works.

You already have a solution well-in-hand: a baton-shaped spaceship around 100 m long or longer, spinning end-over-end at no more than 4 rpm. We already know the unacclimatized can tolerate the spin, and the spin dynamics of rigid bodies is already developed well enough to permit fool-proof design.

We just need somebody to build the thing and try it out. Nobody has, yet.

Well-understood engineering, feasible sizes, within unacclimatized physical human limits. What more could anyone ask?

GW

Last edited by GW Johnson (2019-07-04 09:48:26)

SpaceNut · 2019-07-05 18:46:40

Equipment will always be in a phase of improvement with being able to see as we land as beng very important.
New camera system to offer high-resolution images, video of lunar landing

http://www.psi.edu/news/heimdallcamera

SpaceNut · 2019-10-11 21:29:47

Nasa engineer's 'helical engine' may violate the laws of physics

This is the engine that has no propellant but still creates a force once powered...

tahanson43206 · 2019-10-12 05:53:18

For SpaceNut re #116 .... You were ahead of me on this news. Do you want me to delete the new topic?

The 'helical engine' is (probably) another variation in the well worn Perpetual Motion genre, but the General Relativity wrinkle is a new element.

(th)

SpaceNut · 2020-01-02 19:12:14

The lockheed Base camp is a mission that would make use of near term ships and materials which we can do but there are issues for making use of the lunar orbit gateway for a staging area as it is for the LOP...

Mars_B4_Moon · 2022-05-07 12:30:13

NASA's next crewed lunar rover will be built by a car manufacturer
https://www.tweaktown.com/news/85491/na … index.html

Nissan, Sierra Space, Teledyne Brown, Textron Team For Moon Buggy
https://aviationweek.com/shows-events/s … moon-buggy

Oldfart1939 wrote:

Mars Rover; Tesla Rover?

If Musk is not careful the Rovers of the Cars and Rovers of Future could be of Japanese or Asian knock-off copycat brands?

GW Johnson wrote:

Here is a piece of useful technology we have not discussed before: space lubricants. Looks like they have something vacuum-qualified that will go hotter than my 30-year-old can of C-5A. Goes colder, too. That's actually good.

What Oil Does Nasa Use?
https://www.eclipseaviation.com/what-oil-does-nasa-use/

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#101 2018-08-07 05:13:52

Re: Getting to Mars with REAL technology, & what's currently missing.

#102 2018-08-07 17:04:02

Re: Getting to Mars with REAL technology, & what's currently missing.

#103 2018-08-07 18:56:06

Re: Getting to Mars with REAL technology, & what's currently missing.

#104 2018-08-07 20:16:28

Re: Getting to Mars with REAL technology, & what's currently missing.

#105 2019-01-05 21:28:33

Re: Getting to Mars with REAL technology, & what's currently missing.

#106 2019-02-12 20:57:14

Re: Getting to Mars with REAL technology, & what's currently missing.

#107 2019-03-09 06:32:24

Re: Getting to Mars with REAL technology, & what's currently missing.

#108 2019-03-09 14:30:45

Re: Getting to Mars with REAL technology, & what's currently missing.

#109 2019-03-09 14:43:13

Re: Getting to Mars with REAL technology, & what's currently missing.

#110 2019-03-09 22:37:39

Re: Getting to Mars with REAL technology, & what's currently missing.

#111 2019-04-05 16:38:51

Re: Getting to Mars with REAL technology, & what's currently missing.

#112 2019-04-05 17:21:56

Re: Getting to Mars with REAL technology, & what's currently missing.

#113 2019-07-04 08:55:44

Re: Getting to Mars with REAL technology, & what's currently missing.

#114 2019-07-04 09:35:51

Re: Getting to Mars with REAL technology, & what's currently missing.

#115 2019-07-05 18:46:40

Re: Getting to Mars with REAL technology, & what's currently missing.

#116 2019-10-11 21:29:47

Re: Getting to Mars with REAL technology, & what's currently missing.

#117 2019-10-12 05:53:18

Re: Getting to Mars with REAL technology, & what's currently missing.

#118 2020-01-02 19:12:14

Re: Getting to Mars with REAL technology, & what's currently missing.

#119 2022-05-07 12:30:13

Re: Getting to Mars with REAL technology, & what's currently missing.

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