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#76 2019-12-07 22:15:01

SpaceNut
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From: New Hampshire
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Posts: 19,158

Re: New 2020 Mars Rover based on MSL

https://img-s-msn-com.akamaized.net/ten … 60&o=t&l=f

image link causing machine to be eratic

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#77 2019-12-08 17:54:30

SpaceNut
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Re: New 2020 Mars Rover based on MSL

https://mars.nasa.gov/resources/24676/a … 020-rover/

http://marsnews.com/wp-content/uploads/ … _res-1.jpg

An engineer working on NASA’s Mars 2020 mission uses a solar intensity probe to measure and compare the amount of artificial sunlight that reaches different portions of the rover.

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#78 2019-12-15 21:27:40

SpaceNut
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From: New Hampshire
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Re: New 2020 Mars Rover based on MSL

Another step closer to going to mars
Lockheed Martin delivers Mars 2020 rover aeroshell to launch site

http://www.spxdaily.com/images-hg/lockh … ker-hg.jpg

The backshell and heat shield aeroshell that will encapsulate and protect the needed to send the Mars 2020 rover to Mars. The large mass and unique entry trajectory profile that could create external temperatures up to 3,800 degrees Fahrenheit, the heat shield uses a tiled Phenolic Impregnated Carbon Ablator (PICA) thermal protection system instead of the Mars heritage Super Lightweight Ablator (SLA) 561V.

"Even though we have the experience of building the nearly identical aeroshell for the Curiosity Rover, the almost 15-foot diameter composite structure. Curiosity mission, this is the largest aeroshell/heat shield ever built for a planetary mission at 4.5 meters (nearly 15 feet) in diameter. In contrast, the aeroshell/heat shield of the InSight lander measured 8.6 feet and Apollo capsule heat shields measured just less than 13 feet.

https://www.lockheedmartin.com/en-us/ca … space.html

We will need bigger if we are going to mars with any mass that matters.

Two rovers to toll on Mars Again in 2020

Curiosity won't be NASA's only active Mars rover for much longer. Next summer, Mars 2020 will be headed for the Red Planet. While the newest rover borrows from Curiosity's design, they aren't twins: Built and managed by NASA's Jet Propulsion Laboratory in Pasadena, California, each has its own role in the ongoing exploration of Mars and the search for ancient life.

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#79 2019-12-19 20:05:51

SpaceNut
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From: New Hampshire
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Re: New 2020 Mars Rover based on MSL

science is pushing the detective edge to discover what happened to mars in the past which made it go a different direct when compared to earth.
Developing a technique to study past Martian climate

We have been testing and sampling the geochemistry of Mars with a few rovers but what is that next step?

Lab research will focus on creating silica minerals in the laboratory to discover how they form in subzero temperatures.
http://www.uh.edu/news-events

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#80 2019-12-29 21:31:25

SpaceNut
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Re: New 2020 Mars Rover based on MSL

The conversion of air which can be processed for the co2 there is an energy required to process a given volume at the parts per million rate with in the volume of air process which will give us a net mass of co2 at gas level and then at a liquid volume pressure for temperature.

That said how do we compute some of this?

How much volume does 1 kg of CO2 occupy at room temperature and standard pressure?

CO2 has a molecular weight of 44 g/mol
1 kg CO2 = 1000 g × (1 mol/44 g) = 22.7 mol CO2

V=nRT/P, V=(22.7)(0.0821)(300)/1 = 559 L CO2 at 27°C (300K), 1 atm

This is a little more than half a cubic meter approximately equal to the volume of two bathtubs or the trunk of a large car.

So using the formular we need to suck in since carbon is 12 and oxygen is 16 for a mole mass of 12+32 = 44

1 kg o2 = 1000 g x (1 mol/32 g) = 31.25 mol o2

https://techport.nasa.gov/view/33080
Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE)

producing at least 6 grams of O2 per hour

A scroll pump delivers up to 50 g/hour of atmosphere to the SOXE subsystem.

The Mars atmosphere is processed as follows: the SOXE is warmed to 800 C; the pump is started and the filtered air will flow continuously at >1 torr to the SOXE. The O2 and CO are separated and the flow rate is measured.

Mars 2020 is a Mars rover mission by NASA's Mars Exploration Program with a planned launch on 17 July 2020, and touch down in Jezero crater on Mars on 18 February 2021.

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#81 2020-01-08 19:30:23

SpaceNut
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Re: New 2020 Mars Rover based on MSL

I for one am a little tired of waiting for Nasa to take its foot out of ,,,,,,
Mars 2020 rover to seek ancient life, prepare human missions

"It's designed to seek the signs of life, so we're carrying a number of different instruments that will help us understand the geological and chemical context on the surface of Mars," devices on board the rover are 23 cameras, two "ears" that will allow it to listen to Martian winds, and lasers used for chemical analysis. "What we're looking for is ancient microbial life -- we're talking about billions of years ago on Mars, when the planet was much more Earth-like," when the Red Planet had warm surface water, a thicker atmosphere and a magnetic force around it, he explained.
Mars 2020 will land in a long dried-up delta called Jezero. The site, selected after years of scientific debate, is a crater that was once a 500-yard-deep lake.  It was formerly connected to a network of rivers that flowed some 3.5 to 3.9 billion years ago. The crater measures just under 30 miles across, and experts hope it may have preserved ancient organic molecules.

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#82 2020-01-21 21:27:12

SpaceNut
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Re: New 2020 Mars Rover based on MSL

NASA lists nine potential names suggested by kids for its next Mars rover: Vote for your favorite

NASA and an army of nearly 4,700 volunteer judges have selected nine potential names for a rover that’s due to be launched to Mars in July, and you have just six days to cast an online vote for your favorite name.
NASA kicked off the “Name the Rover” essay contest last August, and more than 28,000 name suggestions and accompanying essays were received from students in kindergarten through 12th grade. It took weeks for the judges to narrow down the field, first to 155 semifinalists, and then to the nine finalists — three for grades K-4, three for grades 5-8, and three for grades 9-12.
The K-4 suggestions are Endurance (from Virginia’s Oliver Jacobs), Tenacity (from Pennsylvania’s Eamon Reilly) and Promise (from Massachusetts’ Amira Shanshiry). In the 5-8 category, the names are Perseverance (from Virginia’s Alexander Mather), Vision (from Mississippi’s Hadley Green) and Clarity (from California’s Nora Benitez). In the 9-12 category, you can pick between Ingenuity (from Alabama’s Vaneeza Rupani), Fortitude (from Oklahoma’s Anthony Yoon) and Courage (from Louisiana’s Tori Gray).
The online voting booth is open until 9 p.m. PT Jan. 27. Poll results will be considered, along with other factors, and the winning name will be announced in early March. The student whose name is selected will receive an invitation to watch this summer’s launch from Cape Canaveral Air Force Station in Florida.

Many also get to have there name sent to mars digitally as well....

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#83 2020-02-11 22:10:36

SpaceNut
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Re: New 2020 Mars Rover based on MSL

Mars 2020 equipped with laser vision and better mics

SuperCam is a green laser that can determine the molecular composition of surface materials, studying mineralogy and chemistry from up to about 20 feet (7 meters) away. SuperCam includes a microphone so scientists can listen each time the laser hits a target. The popping sound created by the laser subtly changes depending on a rock's material properties.

Using a laser beam will help researchers identify minerals that are beyond the reach of the rover's robotic arm or in areas too steep for the rover to go. It will also enable them to analyze a target before deciding whether to guide the rover there for further analysis. Of particular interest: minerals that formed in the presence of liquid water, like clays, carbonates and sulfates. Liquid water is essential to the existence of life as we know it, including microbes, which could have survived on Mars billions of years ago.

SuperCam is essentially a next-generation version of the Curiosity rover's ChemCam. Like its predecessor, SuperCam can use an infrared laser beam to heat the material it impacts to around 18,000 degrees Fahrenheit (10,000 degrees Celsius) - a method called laser induced breakdown spectroscopy, or LIBS - and vaporizes it. A special camera can then determine the chemical makeup of these rocks from the plasma that is created.

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#84 2020-03-05 17:25:03

SpaceNut
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Re: New 2020 Mars Rover based on MSL

Update:

jorgear wrote:

PERSEVERANCE, the new name of the new rover that NASA will launch this year https://www.cnet.com/news/nasas-mars-20 … 05-10aaa0j

Perseverance, persistence, tenacity, pertinacity imply resolute and unyielding holding on in following a course of action. Perseverance commonly suggests activity maintained in spite of difficulties or steadfast and long-continued application: Endurance and perseverance combined to win in the end. It is regularly used in a favorable sense.

The Name Seventh grader wins contest to name new Mars rover launching this summer towards Mars.

Perseverance will search Mars for signs of ancient alien life and collect samples for a future spacecraft to return to Earth.

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#85 2020-03-05 17:52:01

louis
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From: UK
Registered: 2008-03-24
Posts: 5,854

Re: New 2020 Mars Rover based on MSL

"Perseverance" rover due to land in Feb 2021...

https://www.bbc.co.uk/news/science-environment-51761833

Seems to me that NASA are living in world of delusion: "We're hoping in the 2030s that we will be bringing those samples back here to Earth. That'll be incredibly cool."

It won't be incredibly cool because by then Space X will have humans on Mars. It will be incredibly lame. 2030s! What a lack of ambition!!

All these robot rover missions are now the equivalent of flushing money down the toilet.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#86 2020-03-05 19:21:37

SpaceNut
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Re: New 2020 Mars Rover based on MSL

we are off topic from here to post for falcon 9 heavy, sls and starship

I would much rather ask when will man go instead but it seems that we are stuck with the lunar gateway and sls for now until they get serious to going to mars with humans.
It was spirit and Opportunity that Nasa built 2 for the price of 1 so why has the challenge not happened on these newer versions....

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#87 2020-03-08 05:08:57

elderflower
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Re: New 2020 Mars Rover based on MSL

When the Chinese start launching men into interplanetary space, NASA will wake up.

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#88 2020-03-13 16:45:01

kbd512
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Re: New 2020 Mars Rover based on MSL

Louis,

SpaceX already has a rocket that can send substantial payloads to Mars, so why haven't they been using it to stage some consumables and equipment for this upcoming 2026 landing that Elon Musk claims they're going to pull off, if only to prove to themselves that they can do that before they start betting lives on it?

Is it even possible that actually landing anything on Mars in one piece is nowhere near as easy as typing something on your keyboard or putting together a fancy PowerPoint presentation to show how "cool" it will be?

Blind faith and feelings aren't particularly good engineering principles to bet lives on, even if they appeal to people more enamored with the idea of doing something than the hard work required to to take an idea from concept to implementation.

As "lame" as making breathable Oxygen on Mars may seem to you, that's kind of important to living there.  I couldn't help but notice that SpaceX hasn't designed their own device to do that, nor tested one on Mars despite having their own rocket that could send it there, which makes me think they don't have one.

If you're wondering why NASA has spent so much time and money doing all this boring "science stuff", it's so that one day you can have this wonderful Mars colony you've been dreaming of.  Without NASA, SpaceX would not exist, nor the technology to live on Mars.  With all the various space agencies of the world and the billions of dollars at their disposal and multiple decades worth of time to perfect the means to live and work in space, only one of them has ever sent people anywhere but low Earth orbit.  Why is that?  The Russians have talked endlessly about sending people to the moon and to this day they've never done it.  Why not?

Talk is cheap.  Real science and engineering costs a fortune.

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#89 2020-03-13 18:48:42

SpaceNut
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From: New Hampshire
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Re: New 2020 Mars Rover based on MSL

The Raptor engines with new fuel combination could have been tested on the Falcon 9 Heavy as a step towards the BFR but instead we got a machine that can not live up to the hype. It would have been capable of getting to the moon safely with just 2 ships and to mars with a few more. Sure the configuration for a mars lander would still need to be worked on but its do able...

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#90 2020-03-13 20:59:17

louis
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From: UK
Registered: 2008-03-24
Posts: 5,854

Re: New 2020 Mars Rover based on MSL

The US people and government will wake up - not comatose NASA!

elderflower wrote:

When the Chinese start launching men into interplanetary space, NASA will wake up.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#91 2020-03-13 21:08:16

louis
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From: UK
Registered: 2008-03-24
Posts: 5,854

Re: New 2020 Mars Rover based on MSL

First Lesson:

Because Falcon9 Heavy was a dead-end rocket that could never serve the purposes of Mars colonisation...and Musk has confirmed that recently so..."stop going on about it"!

Second Lesson:

If the rocket is big enough, a lot of problems disappear. We saw that even on Apollo 13 - it was a big enough combined craft that there was more than one life support system...so the crew were able to survive.

Third Lesson: 

Seeing what goes up at Boca Chica is not "blind faith", it is faithful observation.

kbd512 wrote:

Louis,

SpaceX already has a rocket that can send substantial payloads to Mars, so why haven't they been using it to stage some consumables and equipment for this upcoming 2026 landing that Elon Musk claims they're going to pull off, if only to prove to themselves that they can do that before they start betting lives on it?

Is it even possible that actually landing anything on Mars in one piece is nowhere near as easy as typing something on your keyboard or putting together a fancy PowerPoint presentation to show how "cool" it will be?

Blind faith and feelings aren't particularly good engineering principles to bet lives on, even if they appeal to people more enamored with the idea of doing something than the hard work required to to take an idea from concept to implementation.

As "lame" as making breathable Oxygen on Mars may seem to you, that's kind of important to living there.  I couldn't help but notice that SpaceX hasn't designed their own device to do that, nor tested one on Mars despite having their own rocket that could send it there, which makes me think they don't have one.

If you're wondering why NASA has spent so much time and money doing all this boring "science stuff", it's so that one day you can have this wonderful Mars colony you've been dreaming of.  Without NASA, SpaceX would not exist, nor the technology to live on Mars.  With all the various space agencies of the world and the billions of dollars at their disposal and multiple decades worth of time to perfect the means to live and work in space, only one of them has ever sent people anywhere but low Earth orbit.  Why is that?  The Russians have talked endlessly about sending people to the moon and to this day they've never done it.  Why not?

Talk is cheap.  Real science and engineering costs a fortune.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#92 2020-03-13 21:13:09

kbd512
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Re: New 2020 Mars Rover based on MSL

SpaceNut,

I think you nailed the exact problem with hype.  Selling ideas and belief systems is insanely easier to do than coming up with a practical solution to an exquisitely difficult problem.  I thought Mr. Musk's Interplanetary Transport System was about the size of the vehicle required to actually do this in one shot, apart from the fact that the leviathan needed to stay in orbit.

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#93 2020-03-14 09:15:56

GW Johnson
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From: McGregor, Texas USA
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Posts: 4,027
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Re: New 2020 Mars Rover based on MSL

Falcon Heavy was and still is capable of sending small things to Mars:  just about 6-to-10-ton objects at most.  Just not anything to do with sending men to Mars.  Its payload to Mars has nothing to do with low Mars orbit or any sort of return.  Direct entry only,  from the interplanetary trajectory. 

This was based on Red Dragon,  essentially a Dragon capsule capable of direct entry and propulsive landing,  carrying a few thousand pounds of items at most.  Something under 2000 kg or 4000 lb.  That's what I got when I reverse-engineered the capabilities of Dragon,  crew Dragon,  and Red Dragon a few years ago,  and posted over at "exrocketman",  by the way. 

Since NASA deleted propulsive landing from crew Dragon,  there was no way for Spacex to get the government to pay for propulsive landing technology development,  and so Red Dragon went away,  too.  Now,  there is no payload vehicle for Falcon Heavy to send to Mars.  No point to trying to fly it there,  unless you have a payload in the 6-10 range that fits the shroud,  and can autonomously effect the direct entry and landing within that 6-10 ton budget.

To send men,  you must send very much larger masses of stuff.  That requires a bigger launch vehicle.  Period.  There is an economy of scale here.  Bigger is better,  until you exceed the material capabilities by taking square-cube scaling too far.  So,  I give you one guess why Starship / Super Heavy is as big as it is. And why SLS is as big as it is.

The difference between those two is not just reusability,  it is also innovation in how to do rocket flight.  Starship / Super Heavy is the new,  more efficient way of managing the entire process.  SLS is entirely the old way,  which shows up as an order-of-magnitude-higher cost.  At least one,  possibly two,  orders of magnitude. 

The new way has been proven to work in the satellite launch business,  but still requires demonstration for manned flight,  and flight beyond LEO.  That's where we are.  Plenty of places to stumble.  And stumble we will.

There are some other preconceived expectations getting in the way,  particularly for those among us who are not development engineers.  One that crops up a lot is the misconception that the very first landing on Mars leads directly to a growing colony.  That is utter bullshit.  Sorry,  there is no other word as accurately descriptive.

The first landing is a small,  temporary thing,  supplied almost entirely from Earth for whatever duration they stay.  Period.  THAT is ALL that we reliably know how to do at this time. 

But,  unless this small party does the right things with the right equipment toward solving how to live there,  then there will be no followup landings for decades,  perhaps a century or more.  That really is true,  too.  Not bullshit at all.

Those "right things" are to experiment with ways to survive self-supplied on Mars.  Oxygen,  water,  power production,  propellant production,  food production.  That sort of thing.  "Doing it right" means running that stuff while the team is there,  and leaving it running when they return to Earth,  to see how well it holds up.  The equipment has to be purposefully designed to do exactly that.

There are NO guarantees that (1) any of this equipment will actually work as advertised,  and (2) that the landing site actually has local resources suitable for the equipment to use.  THAT is why the exploration team's lives CANNOT be bet upon this stuff working,  why they must be entirely supplied from Earth. 

Their mission is the final field test for this stuff.  That test outcome is fundamentally unknown in advance,  if one is truly honest about this.  And that's no bullshit,  either,  although ignoring or denying it,  is.   

My second point in that list is often under- or un-appreciated by correspondents on these forums:  the landing site may not have adequate or suitable resources,  despite what the remote sensing tells us.  You may want to try again somewhere else.  Whether that's another separate mission,  or should somehow be included in the capability of the one "first mission" is something we can debate. 

But history says you cannot have the capability unless you pay for it.  My interpretation is that you can visit multiple sites in the one mission if you base from low Mars orbit.  But you pay an extra delta-vee requirement price to be able to do that.  This is simply and fundamentally NOT AVAILABLE in direct-entry scenarios that save the delta-vee price for low Mars orbit.

Anyhow,  that's my take on this.

GW

Last edited by GW Johnson (2020-03-14 09:39:26)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#94 2020-03-14 13:41:49

kbd512
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Posts: 3,548

Re: New 2020 Mars Rover based on MSL

GW,

If everything SpaceX needs to work is indeed feasible, then a redesigned Falcon Heavy upper stage using a vacuum Raptor, stainless steel balloon tank, on-orbit propellant transfer, and high flight rates with multiple re-uses of boosters and upper stages, are the key technology demonstrations enabling delivery of much heavier payloads to Mars.  As-is, Falcon Heavy could send 30t to LEO with full reusability.  A LOX/LCH4 refill in LEO should increase TMI mass by enough for a crewed lander.

If a Falcon Heavy upper stage started in LEO completely refilled with sub-cooled LOX/LCH4 delivered by reusable LOX/LCH4 tanker flights, how much mass could it throw to Mars?

I'm guessing the tonnage figure is a heck of a lot more than what it can deliver in a straight shot to Mars.  We have to start somewhere and a known-working booster technology with an experimental upper stage with propellant refill capability and new concept of operations is the best place to start.  We could demonstrate precision landing of multiple landers, deliver all the solar panels / batteries / LOX/LCH4 plant / inflatable habitat modules / etc.  Colonization would obviously require much larger rockets, but we've never set foot on the surface and never landed anything heavier than 1t.

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#95 2020-03-14 17:54:20

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,027
Website

Re: New 2020 Mars Rover based on MSL

Well,  Falcon-Heavy can deliver 6-10 tons to Mars as a straight shot.  Its second stage gets that payload from the stage point to the injection velocity for the interplanetary voyage.  That would be from about 2.5-to-3 km/s at staging w.r.t Earth to about 12-12.5 km/s w.r.t Earth.  It's a delta-vee on the order of about 9 km/s. 

If the burnout velocity were instead LEO speed 8 km/s,  then the delta-vee is nearer only 5 km/s.  For that scenario,  the reported payload is some 63 metric tons.  My guess is that if refueling on-orbit were done,  the Falcon-Heavy could send around 40-50 tons to Mars,  instead of 10.  But that's only a guess. 

The infrastructure to refill a Falcon second stage on orbit does not (yet) exist. Neither does the technology to refill on-orbit a Starship.  But they have a concept for Starship (tail-to-tail docking with attitude thruster acceleration),  and they do not have one for a Falcon second stage. 

Kerosene isn't much a problem to transfer,  but a cryogenic is,  because no one has done that yet.  The propellants transferred (by the Russians,  not NASA or anybody else) at ISS are storables.  Not cryogenics.

Supposedly,  a Falcon-Heavy launch to LEO costs around $85 M if flown expendably.  At 63 tons,  that's $1.35M/ton = $1350/kg = $612/lbm.

A Falcon 9 launch to LEO lists for $63M flown expendably,  and sends about 20 tons.  That's $3.15M/ton = $3150/kg = $1429/lbm.  So there is the effect of size for you,  all else being equal.  It's a bit over 2:1 better in the larger size with -Heavy.

All else is not equal,  so there are efficiencies associated with the overall process that an outfit employs to do this.  ULA's Atlas-5 in its 552 configuration lists for around $120M/launch to LEO and sends 22 tons,  inherently flown expendably.    That's $5.455M/ton = $5455/kg = $2474/lbm.  Not everybody does this at the same overall efficiency,  which really means adequate profit margin. 

If you go back to the "old ways" in their entirety,  that's NASA with SLS at $1-2B/launch to LEO and 70 tons in the initial version.  That's $14-28M/ton = $14,000-28,000/kg = $6480-12,960/lbm.  So the commercial guys really have made progress,  and in an SLS-comparable size should be one whale of a lot cheaper(Falcon-Heavy is the same size payload and 10-20 times cheaper per unit delivered payload mass).

There's no guarantee that Spacex will be successful getting Starship/Super Heavy to fly to LEO,  but if it does,  it will deliver more than even the anticipated upgrades to SLS.  The unit price should be substantially better than Falcon Heavy ($612/lbm) at 200 tons vs 70 tons,  but even if it is the same unit price as Falcon-Heavy,  it's still a pretty good deal at $1.35M/ton for 200 tons,  which is 0.27B/launch,  vs $1-2B/launch for SLS.

That's just the observed data talking. 

I hope they succeed. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#96 2020-03-14 19:57:57

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,158

Re: New 2020 Mars Rover based on MSL

If I recall the Falcon 9 heavy expendable can get 63mt to orbit so let it be a fully fueled attachable stage and get redid of refueling.

lets get back to this topic "New 2020 Mars Rover based on MSL" but its been good data to put in the other topics

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#97 2020-03-15 13:01:01

kbd512
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Posts: 3,548

Re: New 2020 Mars Rover based on MSL

Louis,

First Point:

Nobody has ever done a flyby of Mars, much less orbited Mars, let alone landed on Mars.  It doesn't matter in the slightest if you get there and then can't do what you need to do to live there.  That's why we explored on Earth before we decided to colonize distant lands that we knew little about, and that's why I'll continue to "go on about it".  When you have a working rocket that can send a sizable payload to Mars to test your ideas and you fail to even attempt to test your ideas, that doesn't resemble reasonably good engineering practice to me.

Second Point:

If SpaceX needs to send five Starship Super Heavies to Mars to complete the first mission, that invalidates the point about this new rocket being "big enough".  It's clearly not big enough if they need to send five of them on the first mission.

On Apollo 13, we saw that certain parts of the life support system from the lunar lander were minimally capable of supporting 3 astronauts for the handful of days it took to return to Earth.  However, what Apollo 13 really proved was the utility of duct tape and bailing wire for "fixin' just 'bout anything".

I seriously doubt that we want to rely on duct tape and bailing wire to keep people alive for a minimum of two years.  We need properly engineered systems that don't fail unexpectedly because so little testing has been performed on them that we have no clue about how they'll hold up over the period of time they need to operate over.  There's no rush to get to Mars.  Nobody will die because we went to Mars in 2028 vs 2026.  According to you they don't even have any competition, so there's even less incentive to race to the finish line with an untested and potentially defective product- especially if that hurts their ability to use their product for future colonization efforts.

Third Point:

I "faithfully observed" a simple stainless steel pressure vessel so poorly built at Boca Chica that it exploded.  How is it that our aerospace companies have been successfully fabricating rocket propellant tanks from stainless steel since the 1960's, but 60 years later a company with as much rocket building experience as SpaceX isn't building pressure vessels that can withstand a simple pressure test?

I already know the answer to that question.  Nobody working for SpaceX is stupid.  They already know exactly what happens if you don't build something with quality workmanship.  They're feverishly trying to accomplish something without spending the time and effort it takes to build something the way it has to be built to survive a simple pressure test.  Stop confusing activity with accomplishment.

Tory Bruno is literally showing the world how they build the stainless steel Centaur upper stages (I don't expect that SpaceX needs to go to the extreme lengths that ULA does to reduce the inert mass fraction, but they do need to take note of the fact that they're using welding jigs and tooling to obtain uniform mechanical properties from the stainless steel being used):

HOW ROCKETS ARE MADE (Rocket Factory Tour - United Launch Alliance) - Smarter Every Day 231

I'd be willing to bet he'd even serve SpaceX employees lunch if they came for a tour of ULA's factory.

Someone also wrote a book on it:

Taming Liquid Hydrogen: The Centaur Upper Stage Rocket 1958-2002 by Virginia P. Dawson and Mark D. Bowles

SpaceX can keep using LOX/LCH4, but the fabrication methods used by ULA indicate how it is the propellant tanks need to be fabricated to remain in one piece during ground handling and launch.  Having a bunch of guys using cranes and welding out in the open probably isn't the best way to do this.  ULA is using robots to weld the sheets of steel together over purpose-built welding jigs.

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#98 2020-03-15 14:58:51

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,027
Website

Re: New 2020 Mars Rover based on MSL

What Kbd512 says is quite true.  I second. 

There's a longer history to thinwall stainless pressure vessel construction in rockets than just the Centaur upper stage.  The original Atlas was essentially a stainless steel balloon.  It required 4-5 psi helium inflation not to collapse under its own weight when lying on its side.  This is how it was built at the California Convair plant,  at a time when the Ft. Worth Convair plant was just finishing building B-36's. 

Pretty much the same design and construction techniques went into Centaur,  which actually also rode the original Atlas.  Neither looks anything at all like what Spacex is doing trying to build Starship.  Like Kbd512,  I don't think welding hand-bent sheets together out in the open is going to "cut it".  Forming tooling,  assembly jigs,  and precision welding are simply required. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#99 2020-03-27 19:08:49

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,158

Re: New 2020 Mars Rover based on MSL

I sent my name on one of the other mars missions and the surprising number of names on this one is quite something.
Over 10 million names now aboard Perseverance rover bound for mars

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#100 2020-06-13 08:02:41

tahanson43206
Member
Registered: 2018-04-27
Posts: 3,055

Re: New 2020 Mars Rover based on MSL

Here's an update on Perseverance ....

From an article about the expected delay of the James Webb telescope beyond 2021 due to the virus ...

This isn't the only delay that NASA owned up to this week. NASA's Perseverance rover, set to blast off in July, will also be delayed. Fortunately, it's a short one. Due to an undisclosed issue, the rover's launch will only be delayed by about three days.

This is a two year launch window so I imagine NASA would like to be on time if possible.

(th)

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