Space X News - lunar tourism and delayed BFR hop

Void · 2018-09-22 10:59:25

I am going to post about adding retractable feet to 4 of the 6 fin/leg surfaces. Retractable feet like SpaceX already does with Falcon 9.

2 of the 6 surfaces are used for aerobraking assistance to the BFS, so I would be really shy about putting any complex retractable leg extensions/feet on them.

However the two tail fin surfaces might support it, and I wonder if the leeward side of the braking fins would permit it, with careful design.

Each of the 4 leg/feet suggested should be more or less in the slipstream wake.

A bit like this?
https://www.yahoo.com/news/spacex-just- … 46380.html
So, snow shoes. Maybe even an additional part that folds out to increase the circumference of the feet.

Down side is that the "Feet" might get bent, or otherwise damaged. So you would need replacement parts with you.

One obvious help would be to not land on rocks. If the BFS can hover and twist for a short time it might minimize damage from putting the feet on rocks.

After the first landing, rovers deployed from the bottom of the 1st BFS cargo ship might be able to prepare a more friendly landing possibility for the subsequent BFS landings. But surely the travelers will want replacement parts for any such retractable feet.

Hope I did not out one of SpaceX's cunning plans.

Done

Last edited by Void (2018-09-22 11:28:50)

Void · 2018-09-22 11:11:09

I am going to keep this separate from the previous post, because I know that members will be more resistant to proposed changes.

I think it is great that BFS is planed to just make it to the surface of Mars with a self launch from Earth, a tanking up in LEO, a Hohmann transfer. That means it is a fit machine. We hope.

However, there are several schemes which would add to its margins for success.
1) Create a Depot BFS. Send it to Mars orbit. I know, BFS cant stop by to tank up, has to land. Fine. But on your way out you may be able to tank up in orbit. This would reduce the load getting up to Martian Orbit, and reduce the amount of propellants you would have to make or deposit on the surface, for return. And perhaps you would rather eventually have the Depot on the surface. I think you can have it all.
So, the sequence would be to deliver the Depot per O.F. to Martian orbit. Refuel on your way out to Earth. Then the Depot which would be only partially filled with propellants would land on Mars, hopefully near the settlement, and become a tool. Later on perhaps the non depot parts such as engines and navigation equipment would be removed, and transferred to a BFS returning to Earth, to be reused, or maybe they would be repurposed on Mars.

I am pretty sure that at first you want to present the orbital nipple to the baby on it's way out.
Then you want to gradually or ASAP build up the propellant production on the surface to full capabilities, but you will not have to do it on first mission. First mission can do as much as is possible, and doing that gauge more accurately how hard it will be to do the rest on subsequent missions.

At maturity, I expect propellant production to go to Martian orbit. Instead of filling up tankers in orbit with Methane and Oxygen, they would fill them with H20 and CO2. Then the orbital solar energy which is more reliable than the surface solar energy could be used. Of course at this stage we would want to have proven this certain to work. This could be practiced in LEO or Lunar orbit first. By that time synthetic gravity machines and radiation protection sufficient for Lunar and Mars orbital operations should have been created.

2) Another game is to use a special Depot/Booster BFS to Boost your BFS's to high Earth/Trans Lunar orbit before they even fired their engines to go to Mars. It might be, that doing that they could land with enough fuel on Mars, to get back to Low Martian Orbit, and then re-tank in orbit per methods mentioned in #1.

So, I see a vast opportunity(s) to get beyond the limiting margins of the BFS capabilities.

By the way a BFS Depot to Martian orbit should not need to use Hohmann transfer, but I hope could use ballistic capture, and maybe even no aeroburn to Martian orbit.

Done.

Last edited by Void (2018-09-22 11:30:44)

louis · 2018-09-22 11:15:36

Good point about the cargo ring...that could certainly be used for a landing pad robot operation...

Various options might be possible: remove sizeable boulders...lay landing pad sheets of appropriate material (some sort of metal or rubberised material) over a 30 by 30 metres area. Maybe the cargo ring holds 900 1x1 metre pads that can be laid out and put together like a jigsaw by the robots.

Void wrote:

The BFS now has a cargo ring at it's base. This suggests the possibility of dropping small robots to the surface to do scouting and maybe even move rocks and perhaps even more. Of course to do this you first must land a robot BFS to the Moon or Mars.
SpaceX/Elon Musk has discussed building landing pads remotely, but did not have the assurance yet that they knew how.

Void · 2018-09-22 11:26:56

I like it Louis. I was only thinking rocks, but you went further.

Quote Louis:

Good point about the cargo ring...that could certainly be used for a landing pad robot operation...
Various options might be possible: remove sizeable boulders...lay landing pad sheets of appropriate material (some sort of metal or rubberised material) over a 30 by 30 metres area. Maybe the cargo ring holds 900 1x1 metre pads that can be laid out and put together like a jigsaw by the robots.

SpaceNut · 2018-09-22 14:38:20

Hum, robotic surface tile system to land on. Which sounds like a pre mission to layout and make a better one possible.
Make sure that the x marks the spot is layed out correctly....or it might end up looking like a + sign instead...I am sure that the surface area will be larger than the barge it currently uses as BFR is way larger.

Mars orbit refuel depot could be a risk mitigator for any mars mission and it could be delivered via ion drive and gravity capture into mars orbit.

So what would be the minimal launch refuel from mars surface to be able to arrive in orbit to fuel up for the final trip home? Since you are in orbit we will need active cooling for Lox Ch4 to which it makes more sense for hydrogel fuels.

louis · 2018-09-22 16:43:50

Don't think you need any X - the onboard computer could work out where the X is as long as the tiles were of a distinctive nature re the rest of the local rock field.

I think the jigsaw approach to creating a landing pad is feasible with current technology, esp. if there is this low cargo ring on the BFR. Maybe two or three smallish robots go back and forth offloading 1 metre square tiles and placing them in position on a flattish bed of rock.

What would these tiles be made of to withstand the down force of maybe 300 tonnes of mass? How much would each metre square tile mass? What would it need to be made of? how think would it be?

SpaceNut wrote:

Hum, robotic surface tile system to land on. Which sounds like a pre mission to layout and make a better one possible.
Make sure that the x marks the spot is layed out correctly....or it might end up looking like a + sign instead...I am sure that the surface area will be larger than the barge it currently uses as BFR is way larger.
Mars orbit refuel depot could be a risk mitigator for any mars mission and it could be delivered via ion drive and gravity capture into mars orbit.
So what would be the minimal launch refuel from mars surface to be able to arrive in orbit to fuel up for the final trip home? Since you are in orbit we will need active cooling for Lox Ch4 to which it makes more sense for hydrogel fuels.

Void · 2018-09-22 17:57:49

Seems like a good direction. Put snow shoes on the first cargo BFS, give it the ability to hover, hop, and twist, and find it a good location to try.

If the first touch down, seems precarious give it enough fuel to try two more times. Of course this reduces the cargo, but may save the first ship.

…..

Second BFR per Louis and Snow Shoe feet.

We might "Lean" that down however. I see the new BFS as having three fin/legs, but to have four snowshoe feet.

So four distinct pads significantly bigger than the snowshoes.

An interview of the ground site before laying the pads, looking at it with radar/sonar.

Perhaps each pad has wi-fi, and will respond to the landing BFS, to say who they are and where they are.

I had an experience where a car stuck in sand could be extracted by placing a piece of expanded metal under the offending wheels.

I suggest that the puzzle pieces of Louis be pliable with a net of strong cable within, and firm cable linked connections between pieces.

…...

Last edited by Void (2018-09-22 18:01:12)

Void · 2018-09-22 18:02:59

Spacenut said:

Mars orbit refuel depot could be a risk mitigator for any mars mission and it could be delivered via ion drive and gravity capture into mars orbit.
So what would be the minimal launch refuel from mars surface to be able to arrive in orbit to fuel up for the final trip home? Since you are in orbit we will need active cooling for Lox Ch4 to which it makes more sense for hydrogel fuels.

Nothing wrong with what is said above. However I suspect that SpaceX is committed to Lox and Ch4. They do that I suppose because it is easy and relatively safe for Earth operations, and perhaps compatible with Mars.

The SpaceX logic was create the means of travel, which includes a refueling station and then let everything else be the responsibility of others. Not wrong as a first method, but I think it should be updated.

Frankly if it was a model of an animal, it would be one that lays eggs and has limited parenting skills. Time to evolve beyond the start.

The Depot could have active cooling as you have suggested, or just be made bigger to last. Then the boil off might make electricity in it, and part of the result would be water. CO2 to dump overboard most likely.

……

Now about Las Vegas. There are no evil men who will break our bones if we rig the odds in this situation. We can load the dice and count cards if we want to. Nature only cares if we win or loose.

So, now recognizing that we mix the propellant production, and emergency life support options, we could use the depot in at least two ways.

1) As we previously talked this orbital depot could be the method to nurse the BFS from Mars orbit to Earth entry. It would deliver to the BFS Methane, Oxygen, and water for the trip back. Then after the BFS refills and heads to Earth the depot lands to the settlement to be....a depot.
2) Your crew BFS cannot launch or your settlers are at risk of a lack of resources. Return of BFS to Earth is delayed. So, land the Tanker with most of it's contents intact. It has either a MG-Set or fuel cells to generate electricity, and water. So, a life line to stranded settlers/explorers.

Either way then you have a depot with a chemical electrical generating capacity at your settlement.

I like it.

And I have a plan to do that boost to lunar flyby to Mars, now that will also yield pieces for synthetic gravity machines. See Alternate BFR.

Done

Last edited by Void (2018-09-22 18:21:32)

SpaceNut · 2018-09-22 18:21:07

Ya is not an x but 2 concentric circles that allow for it to target the landing zone with the logo x in the middle.

SpaceX-Falcon-9-first-stage-on-an-ASDS-barge-after-the-first-successful-landing-at-sea-final.jpg

https://en.wikipedia.org/wiki/Autonomou … drone_ship

2014 first of such landingsX MARKS THE SPOT: FALCON 9 ATTEMPTS OCEAN PLATFORM LANDING

Returning anything from space is a challenge, but returning a Falcon 9 first stage for a precision landing presents a number of additional hurdles. At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm.
To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns. The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle’s speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle’s speed is further reduced to around 2 m/s.
To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.

The barge moves to the predicted landing area and tries to hold position as the rocket is coming in for the landing. Great for a water landing but mars would only have the land landing.

https://en.wikipedia.org/wiki/Falcon_9_ … ding_tests

SpaceNut · 2018-09-22 18:28:15

spacetechsforum wrote:

I do not think that electric propulsion is of any use in cargo transportation. I cannot give a specific figure, but last time i checked the amount of electrical power needed to generate enough thrust and dv to push heavy cargo (250t+ for payload and ship) to Mars cannot be provided in any feasible way.
My choice is LH2/LOX as it gives the best Isp and I am not a specialist to evaluate the cons of this propellant, although I am currently trying to do so, which brings me to the topic.
Although many NASA publications I found suggest the technology needed for long time LH2 storage seems to be almost ready, I find myself unable to scale provided systems to suit the needs for Mars mission. My first though on this subject was: "Is that not simple? Why not to put a big refrigerator into ship and we are done". Now, as I do not consider NASA scientist to be fools, my understanding is that there must be a serious problem with this approach, yet the thing must be very obvious, since I cannot find any good source that can explain it. I hope someone in this forum will enlighten me.
I did some calculations to comprehend the problem, below the numbers in case i did mistake and so my perspective is flawed.
Model - external shell (const temperature calculated from heat equilibrium - Th=262.15K ), insulation (2xMLI blankets, 22 layers each - E=0.001 ), LH2 tank(Tc=18K). Stefan-Boltzman cost: sigma=5.67E-08
LH2 tank: volume: 464.218m3, surface area: A=353.320m2
Heat Leak: sigma*E*(Th^4 - Tc^4)*A = 94.62W
To remove this amount of heat from tank using Helium as working medium would require a heat pump capable of generating dT=282 with COP=0,03.
That means that we need a little more than 3kW electric power (this much can be provided with 2x18m2 solar panels). If i am correct the 8m2 radiator working at 300K would remove 3,3kW of heat generated by system summed with heat from tank.
The heat pump proposed is 100% theory. The subject of efficiency of cryogenic heat pumps capable of working in space does not seem to be popular on the internet.

We talk all the time about issues in specific topics and then we seem to forget them just as fast

Zero boiloff and active cooling
https://ntrs.nasa.gov/archive/nasa/casi … 023073.pdf

http://newmars.com/forums/viewtopic.php?id=7004

GW Johnson · 2018-09-23 10:24:38

A BFS landing with near-empty tanks will mass somewhere in the vicinity of 200-300 metric tons, if the inert weights of the 2017 version are anywhere near correct. Call it 250 tons. The Earth weight of that would be about 2,450,000 Newtons. On Mars, that would be about 941,000 Newtons.

If the total landing pad area in contact with the surface is 10 sq.m, then the average bearing pressure of the vehicle upon the soil is about 94,100 N/sq.m = 94,100 Pascals = 94.1 KPa = 0.929 atm = 1966 lbf/sq.ft. That's a bit much for sand, especially when multiplied by a factor of 2-ish for the transient impact effects of touchdown.

And just looking at those tip pods where the landing functions are carried, the total pad area available looks like 3 1-m diameter tips, for a pad area nearer 2.3 sq.m than 10 sq.m! Pressures could easily be 4-5 times larger than I am calculating!!!

Once refilled with propellant, the mass is nearer 1335 metric tons. Earth weight 13,090,000 Newtons, Mars weight 5,030,000 Newtons. If the landing pads totaled some 10 sq.m, the soil bearing pressure is 503,000 N/sq.m = 503,000 Pascal = 503 KPa = 4.97 atm = 10,500 psf. That's on the high side, even for desert hardpan.

The risk is sinking into the dirt and getting stuck there like a tent stake. Plus toppling over and exploding, if the sinking is uneven. Which is extremely likely to happen. How will it take off safely if the fins are stuck in the dirt?

What that really says is that Spacex has yet to design the actual landing pads for the rough field landings on Mars. What you are looking at so far (!!!) is a design that requires a thick reinforced-concrete touchdown foundation. Not even steel landing mats on hard dirt would be enough.

I'm pleased they have started looking at the aerodynamics and flight mechanics of entry and landing, which is where the articulated fin design comes from. I'm not sure they have yet addressed the lee side flowfield effects, as regards unintended leeside heating of the windows. You cannot trust CFD alone for that. It requires wind tunnel confirmation at about Mach 5 to be representative of "hypersonic".

I had real experience with exactly that leeside flowfield heating issue before the space shuttle design finalized. The effect is quite real. It gave rise to the tight AOA limits shuttle had for entry: 20-40 degrees AOA, period. No more than 40, no less than 20 degrees.

Spacex has a very long way to go before this BFR/BFS design is ready to attempt flight. They can do it, but they need to be made aware of the real-world troubles others ran into. This kind of crap IS NOT in the textbooks. And, soil bearing strength is a civil engineering topic, not generally aerospace.

GW

Last edited by GW Johnson (2018-09-23 10:33:37)

louis · 2018-09-23 14:44:52

Thanks for the calculations GW, which seem to confirm my intuitive suspicions about what might happen if you tried landing on those fin points on Mars.

Presumably Space X have people who do similar calculations. So the possibilities would seem to be:

1. Robotically, clear the site and assemble a landing pad from steel or other material landing mats. You suggest steel would not work...but I suppose it depends how think the steel would be? And there might be other materials that would work better?

2. Robotically lay a concrete landing pad. How much concrete would be required? Minimum 50 cubic metres? That would be about 120 tonnes at 2400 kgs per cubic metre. 120 tonnes sounds impractical. Could you use less?

3. They will use a different configuration for Mars landing gear...possible perhaps but how would it land back on Earth then? Hmmm...

I was thinking about alternative options...what if you had something a bit like chain mail and the fins had some sort of equivalent of a ski pole basket to stop the fins sinking in. The "basket" might be retractable to the fin I guess. Wondering if you laid several layers of "chain mail" across a landing site it might work quite well over firm ground. .

GW Johnson wrote:

The risk is sinking into the dirt and getting stuck there like a tent stake. Plus toppling over and exploding, if the sinking is uneven. Which is extremely likely to happen. How will it take off safely if the fins are stuck in the dirt?
What that really says is that Spacex has yet to design the actual landing pads for the rough field landings on Mars. What you are looking at so far (!!!) is a design that requires a thick reinforced-concrete touchdown foundation. Not even steel landing mats on hard dirt would be enough.

GW

SpaceNut · 2018-09-23 16:03:03

New art being released :

Mars version
dims?quality=100&image_uri=http%3A%2F%2Fo.aolcdn.com%2Fhss%2Fstorage%2Fmidas%2F1cf0362bf6ba7fa7e85848b05c5cc7d5%2F206684711%2Fmars-base.jpg&client=amp-blogside-v2&signature=9575d711555afb918c6ba9182727becfe4005795

Wow winglets on the nose as well...The space company’s latest Mars project update shows a concept of what the landing base on the Red Planet will look like, as well as the BFR’s new design, which sees bigger fins. It will be a long time until we see the actual bases as Musk previously noted that it will probably take SpaceX until 2028 to build on Mars.

Lunar ship

no winglets on the nose

SpaceNut · 2018-09-23 16:16:27

SpaceX is building the system "primarily of an advanced carbon fiber," which is about as strong as steel at one-fifth of the weight.
The BFR is designed to be a 39-story launch system made of two parts: a 180-foot-tall spaceship, from tip to tail, and a 230-foot-tall rocket booster (which the ship rides into orbit).

180921-bfr-al-1528_5d5f46d33b8dc7738d51abf6e215be27.fit-2000w.jpg

The reusable rocket-spaceship duo will stand 387 feet (118 meters) tall at launch,

https://www.nbcnews.com/mach/science/ho … ncna912121

Most of that increase comes courtesy of the BFR spaceship, whose length jumped from 157.5 feet to 180 feet (48 to 55 m). And the spaceship has changed in other important ways as well. For example, the 2017 iteration featured six Raptor engines, four of which were big-nozzled vacuum versions optimized for in-space use. But now, SpaceX envisions placing seven Raptors on the ship, all of which will be the same "sea-level" engines that power the huge BFR rocket.

louis · 2018-09-23 17:13:31

The BFR with a crane dates back a year I think...hence no winglets. Or should they be finlets.

SpaceNut wrote:

New art being released :
Mars version
https://o.aolcdn.com/images/dims?qualit … cfe4005795
Wow winglets on the nose as well...The space company’s latest Mars project update shows a concept of what the landing base on the Red Planet will look like, as well as the BFR’s new design, which sees bigger fins. It will be a long time until we see the actual bases as Musk previously noted that it will probably take SpaceX until 2028 to build on Mars.
Lunar ship
https://s.aolcdn.com/hss/storage/midas/ … alpha.jpeg
no winglets on the nose

GW Johnson · 2018-09-24 16:46:33

OK guys, the available data are very sparse, but I did the best job I could, reverse-engineering the performance and characteristics (and risks) of the new finned BFS second stage for 2018. That is an article dated 9-24-2018 and titled "Relevant Data for 2018 BFS Second Stage". It is posted at my "exrocketman" blog site http://exrocketman.blogspot.com. It is the latest thing posted for the time being.

GW

louis · 2018-09-24 17:36:44

Very interesting analysis. You a little more disposed to the finpoint landing than before you did your calculations. It sounds like they could land on a natural rock platform with less than 5 degrees tilt. I think you could with reasonable confidence get a robot rover on site to clear rocks and boulders from the identified landing site.

I recall that at the NASA event a few months ago, some rock platforms have already been identified. I'll maybe try and find the reference to that.

Seems very likely they will go for a site like that. Of course it has to have good water sourcing as well.

GW Johnson wrote:

OK guys, the available data are very sparse, but I did the best job I could, reverse-engineering the performance and characteristics (and risks) of the new finned BFS second stage for 2018. That is an article dated 9-24-2018 and titled "Relevant Data for 2018 BFS Second Stage". It is posted at my "exrocketman" blog site http://exrocketman.blogspot.com. It is the latest thing posted for the time being.
GW

GW Johnson · 2018-09-25 09:09:16

I've never been against landing on fin tips. If you need fins anyway, that's a better solution than landing legs, because (1) they don't add the failure mode associated with deployment, and (2) the footprint dimension is inherently as large as, or larger than, can be achieved with folding landing legs.

What bothered me with both the landing legs illustrated before, and now the fins, is the small sizes of the surfaces in contact with the landing field surface. The soil bearing pressures are simply too high, even on Mars, for anything but solid rock, or else thick, hard pavement. If you start deploying additional surface area with some sort of fold-out pad, you went and added another failure mode.

Adding failure modes is a bad idea! Any space vehicle already has more than enough of those.

Without some sort of terminal navigation guidance, landing accuracy is measured in km, not m. That kind of navigation guidance involves some sort of satellite positioning system for fine course corrections prior to entry, and some sort of transponder or homing beacon to guide the final seconds to touchdown after entry hypersonics (and the radio/radar-killing plasma sheath) end. During entry, you rely on inertial navigation, which won't drift, because the timeline is a small handful of minutes.

With such guidance, one might expect to hit the target flat rock outcrop. Without it, one will most likely miss the target. You cannot address that by hand-waving, it takes real hardware.

As I indicated in the "exrocketman" article, a near-empty BFS could land on sand/rock regolith mix, but it will be stranded there, regardless of whether propellant can be produced or not. That soil simply cannot support a fully-fueled BFS, even at 0.38 gee.

It would most likely topple over as you refill it, but if not, you would likely damage the fins pulling them out of the dirt upon takeoff, even if you applied enough thrust to extract them. Damaged landing fins mean a crash upon landing on Earth. And there is no stopping in Earth orbit for rescue. You haven't the propellant to make that burn, by about a factor of 4.

It's things like that, and there are many of them, which induce me to say there are real risks of single-point failures with this mission architecture and vehicle design. It has huge advantages, yes, but these were purchased by deliberately incurring those risks. You have to be aware of that.

That being said, the latest quote from Shotwell targets flight testing by 2020, the moon mission by 2022, and a Mars mission by 2024. That's a 2 year slip from Musk's hopes, and I think it'll slip another 2 years before they get it all done. And that assumes they don't lose one during testing. Add about a year for every crashed test vehicle.

GW

Last edited by GW Johnson (2018-09-25 09:15:52)

louis · 2018-09-25 11:13:23

louis wrote:

Very interesting analysis. You seem a little more disposed to the finpoint landing than before you did your calculations. It sounds like they could land on a natural rock platform with less than 5 degrees tilt. I think you could with reasonable confidence get a robot rover on site to clear rocks and boulders from the identified landing site.
I recall that at the NASA event a few months ago, some rock platforms have already been identified. I'll maybe try and find the reference to that.
Seems very likely they will go for a site like that. Of course it has to have good water sourcing as well.
GW Johnson wrote:
OK guys, the available data are very sparse, but I did the best job I could, reverse-engineering the performance and characteristics (and risks) of the new finned BFS second stage for 2018. That is an article dated 9-24-2018 and titled "Relevant Data for 2018 BFS Second Stage". It is posted at my "exrocketman" blog site http://exrocketman.blogspot.com. It is the latest thing posted for the time being.
GW

GW Johnson · 2018-09-28 13:14:19

I don't know why Louis copied his own earlier post 67 in post 69 above, as a reply to my post 68 above. But I did look at the landing pad area problem and added the results to my reverse-engineering of the 2018 BFS, on my "exrocketman" site, as an update dated 9-28-18.

By reshaping the fin tips slightly, much larger bearing area can be had without any complex folding structures, which makes landing and takeoff from compacted sand and gravel soils requiring picking feasible. That's a much wider range of feasible landing sites.

If anybody has an inside contact at Spacex, point this out to them. The article is "Relevant Data for 2018 BFS Second Stage", posted 9-24-18, on http://exrocketman.blogspot.com.

GW

louis · 2018-09-28 14:40:09

Late night error I expect.

GW Johnson wrote:

I don't know why Louis copied his own earlier post 67 in post 69 above, as a reply to my post 68 above.
GW

louis · 2018-09-28 14:51:37

GW I don't know why you claim Shotwell stated they were targeting flight testing by 2020...do you mean orbital flight? That is probably right. But hop flights are still scheduled for 2019 although there seems to have been some slippage there by a few months from Musk's original statements. The Moon mission will be a human-rated flight. If they are ready for that in 2022, then I see no reason why the robot cargo flights to Mars can't take place in 2022. The Mars Mission in 2024 is the human landing. If you've got any evidence that the Mars Mission has slipped by 2 years can't you give us the quote?

GW Johnson wrote:

That being said, the latest quote from Shotwell targets flight testing by 2020, the moon mission by 2022, and a Mars mission by 2024. That's a 2 year slip from Musk's hopes, and I think it'll slip another 2 years before they get it all done. And that assumes they don't lose one during testing. Add about a year for every crashed test vehicle.
GW

Last edited by louis (2018-09-28 17:55:49)

GW Johnson · 2018-09-28 16:14:56

Louis:

It was a quote I saw somewhere on the internet, I did not record where. Had something to do with status of BFR/BFS, that's all I know. Short hop BFS second stage-alone tests of late 2019 she was talking about might really take place in early 2020. Nothing to do with orbital flights at all.

Not surprising, since not one airframe has yet been built. They've built some tubes but no bulkheads, for propellant tanks. No engine sections, no payload sections, no nested tanks inside the main tanks. No fins. Why would you be surprised about a schedule slip? You should not be surprised. Right in the trend of Musk years vs real years.

They will have to send something unmanned to the moon before sending anything manned, much less with paying passengers. No, the manned moon mission is 2022 , not 2020. At the earliest.

Yes, if they can send something unmanned to the moon in 2020-2022, they can also send something unmanned to Mars shortly afterwards. There's not a whole lot of difference. That's experimental, NOT operational.

Sending an operational (operational, not experimental !!!!!) cargo mission to Mars in 2022 is just utter BS. They'll be lucky to get that done on 2024. Just as I said.

Meanwhile, NASA is on a track never to go to Mars with men at all. They are on a track to kill a crew at the moon (NOT on it) due to a solar flare.

My hopes really are with Spacex. But I know they have bitten off more than they can chew, just yet. Give them a bit more time. Spacex years to actual years is down to about 2:1 now. It was higher.

GW

Last edited by GW Johnson (2018-09-28 16:19:10)

SpaceNut · 2018-09-28 16:25:03

One thing that I note is that the foot pad is in the heat stream of entry which will need TPS materials or the Paint on that side or the wing needs to bumpout in a cone shape to hide the air flow from the surface that will become abrative even if we use high temperature metals if we do nothing.

louis · 2018-09-28 18:01:04

I'd be surprised if there isn't slippage. I think there is still an outside chance that they can hit the 2022 cargo flight target. It really depends if everything works like a dream (not impossible - that's pretty much what happened with Saturn V).

But as far as I know there has been no official announcement of a postponement of the Mars Mission target of 2022, just a few months slippage on the hop flight from first half of 2019 to "late 2019".

One good thing is that some of the criteria affecting previous rocket development e.g. operating in the vicinity of the ISS will not be present. This is much more a Space X -owned project though there will be dependency on NASA launch facilities and coms. But they can afford to take some risks with the cargo flight.

GW Johnson wrote:

Louis:
It was a quote I saw somewhere on the internet, I did not record where. Had something to do with status of BFR/BFS, that's all I know. Short hop BFS second stage-alone tests of late 2019 she was talking about might really take place in early 2020. Nothing to do with orbital flights at all.
Not surprising, since not one airframe has yet been built. They've built some tubes but no bulkheads, for propellant tanks. No engine sections, no payload sections, no nested tanks inside the main tanks. No fins. Why would you be surprised about a schedule slip? You should not be surprised. Right in the trend of Musk years vs real years.
They will have to send something unmanned to the moon before sending anything manned, much less with paying passengers. No, the manned moon mission is 2022 , not 2020. At the earliest.
Yes, if they can send something unmanned to the moon in 2020-2022, they can also send something unmanned to Mars shortly afterwards. There's not a whole lot of difference. That's experimental, NOT operational.
Sending an operational (operational, not experimental !!!!!) cargo mission to Mars in 2022 is just utter BS. They'll be lucky to get that done on 2024. Just as I said.
Meanwhile, NASA is on a track never to go to Mars with men at all. They are on a track to kill a crew at the moon (NOT on it) due to a solar flare.
My hopes really are with Spacex. But I know they have bitten off more than they can chew, just yet. Give them a bit more time. Spacex years to actual years is down to about 2:1 now. It was higher.
GW

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