SpaceX Delays Near Term Mars Plans
SpaceX informed NASA of slowdown in its commercial Mars program, SpaceflightNow
“Confirming rumors and suspicions that SpaceX is adjusting its plans to begin dispatching robotic landers to Mars, NASA officials said the commercial space company has informed the agency that it has put its Red Dragon program on the back burner. Under the terms of a Space Act Agreement between NASA and SpaceX, the government agreed to provide navigation and communications services for the Red Dragon mission, which originally aimed to deliver an unpiloted lander to Mars in 2018. SpaceX confirmed earlier this year the launch of the experimental lander on a Falcon Heavy rocket had slipped to 2020.”
– SpaceX Will Go To Mars Starting in 2018, earlier post
– NASA’s SpaceX Mars Mission Briefing That NASA Is Not Telling You About, earlier post
Fully expecting that moonshot mission to slip now, too.
I never bought in that SpaceX or anyone else will send humans to the moon anytime soon. 2018? Nope. 2020? Nope. 2025? Nope.
Just out of curiosity, why not? The first flight of the Falcon Heavy does keep slipping, but it’s now only three months away. I’d certainly think it would be available by 2020. The same is true of Dragon 2, which is currently supposed to be in service next year. Even a slip there would have it available by 2020. A Falcon Heavy can get Dragon 2 onto a trans-lunar, free-return trajectory. The Dragon 2’s life support system is designed for more than the required duration, and the reentry speed is also within the spacecraft’s capabilities. What’s missing which won’t be in place by 2020 or 2025?
Hopefully I’m wrong(I usually am lol), I just get the sense that it’s going to take a lot longer than we expect for Elon and Co. to make the giant leap into successful human spaceflight.
I will say this, I was impressed that Elon made a remark recently something along the lines that there’s a lot of support to build a colony on the moon before going to mars.
Still, my current expectations it will take about 3 more years before SpaceX can send humans to the space station and that flying to the moon and/or mars won’t be before 2025.
I also wonder about that view.
Many like to point out the schedule slippage that SX encounters. But I like to remember two numbers: 1 and 5.
$1B + 5 years = a clean sheet, reusable booster including a clean sheet, new engine.
That is one hell of a track record, my friends, and with it SX buys lots of credibility.
So, yea, FH is late. Launching people is late. But I expect to see one hell of a rocket this fall and I plan to be there to watch it.
Three more years before Dragon 2 flying carrying crew to the space station would be about 360% longer than planned (the current schedule has the first manned flight to ISS no earlier than June, 2018.) SpaceX has a reputation for schedule slips, but not that much. Are you more optimistic about CST-100?
I haven’t been following the development of the CST-100 so I can’t comment on it. Back to SpaceX, hopefully I’m wrong but I certainly don’t see them launching humans next year, 2019 seems a stretch(but I’ll agree it’s a possibility) and 2020 seems about right.
And that announcement by SpaceX going around the moon with 2 paying passengers in 2018? Just a lot of rhetoric.
CST has some clever points. It uses the actual air bag landing system originally designed for Orion before the latter got too overweight to use it. In fact the entire CST is pretty much what Orion would have been if it had adhered to William Bushnell Stout’s admonition for aircraft designers, “Simplicate and add lightness”.
As a wilderness backpacker, I am definitely going to use that line.
I just came across the following plot:
https://uploads.disquscdn.c…
It’s the planned time until the first Falcon Heavy launch and the time until launch, as a function of time. The Falcon Heavy schedule has slipped, but by significantly less than one month per month.
It probably will, especially with Falcon Heavy development continuing to drag on.
Only as related to FH and Commercial Crew delays. Crew Dragon can parachute into the drink just like Orion – both sets of chutes being made by the same contractor.
NASA didn’t want propulsive landings for Commercial Crew or Cargo, which would have been on the critical path leading to Red Dragon using a Dragon 2. No propulsive landings, no Red Dragon.
This does not mean “Red xxx” missions using the 9 meter subscale ITS (NSF’ers are calling it “ITSy”) can’t be done when it’s ready. Judging from the plume ground effect images reaching some 600′ from the Raptor test stand that motor is coming right along.
“NASA didn’t want propulsive landings for Commercial Crew or Cargo”
I’ve heard this by many and wonder if there’s an explanation for NASA’s position (if true)?
I haven’t seen any NASA policy statements on the subject. But I suspect it would be more accurate to say that NASA did not see the need for propulsive landing, and was not interested in compromising capabilities or reliability for a feature they didn’t consider necessary.
Am I the only one seeing this ‘preference’ as emblematic, at least to the extent that landing in salt water immediately trashes the equipment, locking the entire enterprise into yesterday’s” use and throw away” mentality, and obviating re-use?
Or, as I think Mr. Stetler is saying, are they simply making lemonade?
What? You expect capsules to be reusable or something? HSF capsules fly once, splashdown in water, then are given to a museum to honor the crew. That is how NASA has always done it in the past, why do you want to do something different. 🙂
Really, you must learn to think the NASA way 🙂
I agree, but that results from NASA’s failure to recognize the critical nature of operational cost for the future of human spaceflight, and the need to leverage unmanned flights to accelerate design evolution. Unfortunately it’s difficult to impossible at NASA to get a program to accept an acknowledged risk, however minor.
For one thing, qualifying landing leg deployment through the heat shield. It would have taken a long time and cost $$$$, money and time better spent on the ~9 meter subscale ITS and its big brother. With Raptor undergoing frequent tests, F9 Block 5/Commercial Crew (the latter requires the former) and FH approaching deployment it’s time to move on to building the next-gen methane architecture.
Is there any recent data on the “scaled down” Raptor powered booster? What little I have seen seems a lot more realistic than the ITS.
Capsules have always returned by chutes on water. The Orion returns by chutes on water. That is why they call returning by capsule a splashdown. No way NASA will let SpaceX recover its capsule on land to show them up.
Soyuz? They land on, well, land. It’s a non-reusable mix of parachutes, retrorockets and (I think) crushable structure as a shock absorber. Thats quite different from the propulsive landing originally planed for Dragon 2, but it is on land and not in the water. I think Shenzhou are similar to Soyuz (despite claims to the contrary, there is significant design heritage between Soyuz and Shenzhou) but I’m not sure. Online details about the Chinese space program tend to be a bit sketchy.
I’m recognizing a certain prejudice on my part: propulsive landings compared to splashdown just feel more advanced.
And of course the fact that salty water essentially nixes any sort of re-use, which is all about the future.
SpaceX has reused at least one Dragon after ocean recovery; the amount of maintenance was unclear. The problem with Orion is that it isn’t entirely clear what might be exposed to sea water. That said, the cost of ocean recovery is considerably higher than land recovery due to the infrastructure and overhead required. Propulsive precision landing is a viable idea for spacecraft as well as boosters, and NASA will pay a price for rejecting it.
China currently uses a Soyuz-like (but Chinese designed) system for land recovery, but the new larger Apollo/CST-like human spacecraft being designed for the LM-7 will be recovered offshore in the South China Sea in the area due east of the new launch center on Hainan Island. I think this may have been driven by their lack of experience with airbags and the need for overwater launch abort landing capability for human launch at Hainan. That said, the South China Sea, like the Gulf of Mexico, is a much calmer body of water than the open ocean and should present little risk.
Boeing is planning to use exclusively land recovery for CST.
This—along with removing Draco from the capsule, forcing a water landing—is disappointing.
The Draco (and Super Draco) engines are still part of the Dragon 2 design. They need them for on-orbit maneuvering, attitude control (Dracos) and launch abort (Super Dracos). What they’ve removed are the landing gear.
I think the original plan was to extend them through some sort of door or hatch in the heat shield, and the primary customer didn’t care for the idea (or would have required lots and lots of work before certifying it.) I suppose some sort of landing gear extending from the sides and down would be possible. But it would probably have a significant impact on payload to and from the space station. Again, the primary customer isn’t interested in that.
Which is silly given that the launch vehicle’s capability has nearly doubled.
It could be a payload volume issue, not payload mass. I don’t have any drawings or CAD files on the subject, and I suspect you don’t either. I think the most we can safely say is that the people who do know the details decided not to pursue this option.
Then I didn’t understand your previous comment: Why would legs on the sides (a la F9) reduce payload volume?
I was assuming they would actually be inside the vehicle during reentry. For a F9 first state, entering the atmosphere at something like 1.5 km/s, the outside surface can have some lumps and bulges, but at 7.5 km/s or more, I’d think they would want a nice, smooth surface. And you might not want to expose the landing gear to othe external temperature. The sides don’t get as hot as the bottom, but the do get pretty hot. All that suggests internal storage during the reentry (at least to me), with hatches to open and landing gear to fold out and down.
Ah. I get your comment now. But given that D2 has the additional “lumps and bumps” of the Superdraco enclosures, I would think that a discrete, externally mounted leg system would be fairly simple.
(I would think a telescoping design within an aero enclosure, running down the sides of the capsule. Foot folds up to cover the opening when the leg is retracted, bottom of the foot-pad covered with ablative or PICA-X. Not as tidy as the original design, but it prevents breaks in the main heat-shield.
For eg,
https://uploads.disquscdn.c…
I’m sure you could do something like that. There are probably other possibilities as well. But now you are changing the aerodynamics of the vehicle. It’s probably a trivial change, but I suspect any change would require all sorts of rework. Just about any change invalidates some of the analysis and testing of the previous configuration.
Which is odd considering how many openings were in the bottom of the space shuttle (three ET attach points/fuel and oxidizer, and three for landing gear).
In the sense of formal logic, it isn’t inconsistent. Of course, in formal logic, if your initial assumptions are flawed, you can reach a consistent but incorrect conclusion.
Axiom 1: NASA has procedures and accepted practices for designing and building a reentry vehicle.
Axiom 2: Those procedures and practices assure an acceptable level of reliability and safety.
Axiom 3: Private companies have different practices and procedures.
Axiom 4: NASA has less visibility into those private companies’ practices and procedures.
Therefore, if design with potential risks is developed by NASA, NASA can automatically assume appropriate practices and procedures will be followed. If the same design is developed by a private company, NASA can not automatically assume this will be the case. Therefore, potential risks should be avoided in a privately developed vehicle but can be accepted in a NASA developed one.
The initial assumption that the NASA “best practices” are actually “best” (or even better) is very debatable. But if you believe that, then the rest follows.
I’ve seen the same thing with deployables (antennas, booms, etc.) on unmanned spacecraft. NASA centers and JPL get nervous if a instrument subcontractor is providing them (“What if the boom sticks when it’s only half deployed?”) but are perfectly comfortable with the same systems if they are developing them in house. In fact, they sometimes go for more complex designs, since it’s a challenge, and they are confident _their_ can handle it.
In short, since NASA didn’t develop it using their methods, it’s suspect. Therefore, the burden is on the contractor to prove to NASA that the engineering is sound and the testing valid, which might improve safety, but it most definitely drives up costs.
Trying to balance “even though it’s expensive, we’ve always done things this way and it’s never failed” with innovation intended to drive down costs is tough.
Especially since the statement, “”even though it’s expensive, we’ve always done things this way and it’s never failed,” isn’t, strictly speaking, true.
True. As an example of this, the NASA/political support for large segmented rocket boosters is mind boggling to me. We know from the shuttle that they’re relatively inexpensive to develop, but hideously expensive to build and fly. They’ve also been touted by NASA and Orbital ATK for how infrequently they’ve failed on the space shuttle (just once out of all shuttle flights), yet the ones on SLS are not the same, so their safety has yet to be proven. And the icing on the cake is that the SLS SRBs will not be recovered, so there is zero opportunity for post flight inspections like there was with the space shuttle (which did identify the “anomaly” of o-ring erosion long before the Challenger disaster).
Who says the issue is with heat shield openings?
True, NASA could also have issues with other aspects of the system.
Yes it’s disappointing, but there has been some talk that SpaceX has changed its landing mode for Mars in some way, negating (some of) the direct traceability to a Dragon 2 vertical landing.
That’s disappointing. Red Dragon would have at least demonstrated a powered landing with a much more massive craft, something very useful for future crewed and robotic missions. Now it’s probably going to disappear off into “paper space mission” plan land.
I wouldn’t rule out a Red Dragon landing. With six tonnes of payload, there are quite a few options. But it wouldn’t be they same Dragon 2 they will be using for ISS crew transfers.
[Note added later: I’m not sure where I got that six tonne number. That’s my memory from a previous discussion of what science payload would fit on a Red Dragon. The correct number may be lower, but there is still enough available mass for a propulsive landing Dragon variant to be viable.]
In any case, it’s interesting to compare this with the MSL/Mars 2020 sky crane. One of the expressed purposes of the sky crane is to keep the decent rocket plume from contaminating or disturbing the surface. Having a big strong ammonia peak in a mass spectra, simply because ammonia is a hydrazine combustion product, just wouldn’t do. And blowing the fines off the surface for meters (tens of meters?) in all directions would mess with studies of surface properties, dust transport and geology. A Red Dragon landing would do all of that. So it might not be the ideal platform for some scientific investigations.
The payload of Red Dragon would be around 2 metric tons, 6 tons is the total mass landed on the surface, including Red Dragon itself.
You could just drive the rover a hundred meters or so before doing the science..,
To be fair, contamination wasn’t the primary reason for the sky crane, although it was mentioned. I believe contamination is the main reason the Europa Lander concept uses a sky crane. Like the Red Dragon concept, that would be a stationary lander.
Perhaps disappointing but actually a diversion from the real Mars track. SpaceX was never going to land their ITS this way so now they’ve decided to scale down their original ITS and go the direct route.
Cheers
You really can not blame Musk for the direction he took. Even when he first announced the Mars greenhouse the push for Mars was already present. Just a couple years after SpaceX started in 02′ the Bush administration announced the VSE and moon mars and beyond. It was a good bet for SpaceX and then the Obama administration still kept Mars in the cross hairs and so did SpaceX.
But a fundamental shift has taken place and it looks like Mars is now off the table. Where as SpaceX could probably have competed and got some partnership funding help it no longer looks that that is in the cards. So SpaceX will have to focus more on cislunar now..
Not sure I agree with this assessment. For one thing, to what extent was Mr. Musk’s Mars adventure informed by NASA’s plans (whatever NASA’s plans might be)? Not much; he wanted to go to Mars back when he was shopping Russia for rockets, way before Falcon.
It’s possible that you are correct that something of a shift has occurred, but Id hesitate calling it a “fundamental shift’; as far as I can see there’s really nothing fundamentally happening at NASA WRT either Mars or Luna or with any possibly enabling technologies. And don’t count on leadership from Penna. Ave.
Mr. Musk wants to settle Mars. Luna cannot really be a substitute; many here much smarter about the types of tech needed have made the case that the two are very dissimilar.
We have to assume that there is quite a bit of research happening at SX that will enable a Mars Mission, and we miust take Mr. Musk at his word that he has something altogether in mind as a replacement for Red Dragon. Space cadets like me can only wait and see, still disappointed in the water landing, but confident that something cool is happening.
And this: NASA is both a bystander and a vendor to Mr. Musk’s Mars plans. I don’t see anything that’s changed.
Elon Musk is probably learning that what he wants and what the NASA Planetary Protection Office will allow are two very different things. NASA simply will not allow any humans on the planet until they are sure they won’t harm any life there, They may let him have the Martian moons, but the surface is off limits.
Aside from guessing about the planetary protection office’s involvement and intentions (which is just speculation), I don’t see it as that cut and dried.
The current standards are simply their interpretation of the Outer Space Treaty and the COSPAR reports on the subject. Other countries have different interpretations and different standards. So PPO’s requirements are subject to change for a wide range of reasons.
They have said the requirements would change, in advance of any human landings. How and when isn’t clear, but some change is. And PPO works for NASA, and its Director, who in turn works for the President. PPO could be told by their management that their standards are unrealistically strict and directed to revise them. Whether or not that would happen to allow a SpaceX landing isn’t at all clear, but it also isn’t impossible.
Yes, political pressure could be put on the PPO, but as we are seeing with climate change, or with endangered species, there could be push back as well.
There is not much room for interpretation because ESA and NASA PPOs are following a combined approach. Most of the documents of NASA and ESA for PP vary little. Even Roscosmos is closly connected and is on a very similar approach. Exomars includes all three parties and they had to get together. A strong change of the NASA PP for Mars2020 or Red Dragon very unlikely.
I’d agree with that timescale; I don’t see anything happening before the 2018 or 2020 launch windows. But I think the planetary protection rules after the mid-2020s are an open issue.
While NASA has Mars “in the crosshairs”, there is no funding available to develop any hardware for a human exploration mission in the budget. Anything beyond a few SLS and Orion missions is strictly a few paper studies and viewgraphs.
NASA just started ground test habitats. Converting Shuttle cargo module.
“Just started ground test habitats”?
Not sure what you mean. NASA has been experimenting with Earth based simulations for decades?
I’d have to track down the press reports, but I saw something about this a month or so ago. Someone has a contract to look at habitat designs with a focus on the Orion-serviced deep space (or lunar orbit) waypoint. I.e. the idea NASA is currently putting on their viewgraphs. The work is using a flight spare for either SpaceLab (Shuttle) or of an ISS module. I can’t remember which. Honestly, and as you point out, this didn’t strike me as all that significant given the maturity of the current concept and the past work. Maybe that’s why I didn’t pay enough attention to remember the details.
Yes, they are looking at doing a “Lunar Gateway” station as a way to justify the SLS, just like the Space Station Freedom/ISS was used to justify the Shuttle after the Challenger accident.
There is talk of converting one of the MPLM modules into a habitat module. My guess is that you’d have to strip it down to bare structure in order to do this. It will no doubt need better/different MMOD protection on the outside.
Not for Mars. Prototyping Cis-Lunar stuff only. Again, another bridge to nowhere.
Cancellation of Red Dragon has very little to do with the shift to the Moon, the main reason is NASA doesn’t want propulsive landing test on cargo flights, which made testing propulsive landing difficult and expensive.
Interesting. I was wondering about that. With all the work they did on propulsive landing, it was an unpleasant suprise when SpaceX dropped it. The NASA decision still remains hard to understand.
My reading is that ISS managers don’t want SpaceX treating CRS missions with return-cargo as test flights.
Hmm. Isn’t it the case that, at least to some extent, every SX flight is some sort of test flight? I don’t mean that in the general way, that one learns from experience.
Which is true, but I men it more specifically. We’ve seen the evolution of Falcon, for instance, through multiple, successful launches, as F9 became quite a bit more muscular with time.
Yeah, but I don’t think certain key decision-makers at NASA like it.
If you look at recent comments from Musk, Shotwell and co, they are emphasising that the design is going to be “mature” this year. Block 5 is the last significant upgrade, and is mainly focused on being the final upgrade for F9.
Meanwhile, they also talk about other upgrades, like experiments with fairing recovery, eventual US reusability, etc. Which is a weird clash with the idea of F9 now being “mature”, polished, reliable, finished.
Hence I don’t think we are the intended audience for those comments.
Ha! For sure.
It’s hard to see ANY sort of space effort “mature”.
That attitude toward distrusting an evolving design sounds like the old joke about doctors practicing medicine. I’ll trust them once they are done practicing.
As a doctor, I resemble that remark. Seriously, I’m 65 and still learn something new every day. Except for the most trivial cases every patient is a passenger on a test flight. When you are dealing with a real person with real problems, the “literature” often fails to provide anything useful. You have to learn by doing, with the patient as a fully informed partner accepting potentially serious risks.
Similarly the NASA decision not to permit continuous design evolution and testing on unmanned cargo return flights will set back the progress and increase the cost of human spaceflight. The return cargo is important, but the development of precision spacecraft landing is MUCH more important. The “safe” choice for replaceable cargo will prolong the acceptance of risk and cost when irreplaceable human lives are at stake.
“Cancellation of Red Dragon has very little to do with the shift to the Moon, the main reason is NASA doesn’t want propulsive landing test on cargo flights,”
That is why I called it a fundamental shift. That had to take a heck of chunk of wind out of their sails and would mean a new clean sheet design I would be guessing. That means a few years at the very least.
Yes, definitely interesting. I wonder if they could arrange for a propulsive landing test for a mission that doesn’t return anything really significant including any science experiments. I don’t know what demand there is for return mass. Maybe they really need every bit they can get back down. If so, kind of a shame there as it’s like they are a victim of their own success. They are almost the only return capability there, but because of that (and NASA’s alleged decision), they can’t do a test on the return.
This has all happened before. The first cycle was in the 80s then late 90s and now again. Mars is always 30 years away, and absolutely no one has the money, power or inclination to change this.
So true! I was between 10th and 11th grade when we landed on the moon. I am now 64 about ready to apply for medicare. Space flight has in a very real sense been stolen from my generation. John Glenn was in low earth orbit. “Mars is always 30 years away…” indeed!
Certification for crew was enough of a leap, with NASA requirements phrasing leaving room for NASA to say “more”, even when firm fixed price. Notice the near order of magnitude difference in development cost, crew Dragon vs. cargo. The idea of the landing legs ran counter to the simple idea of doing most challenging things first on cargo missions, using success there to pave the way for crew certification, managing the cost delta. I should have seen this change back to water coming.
Yes. I’d guess it is a short term acquiescence to NASA.
EDIT: Turns out the reasoning is a bit more finely tuned, as it so often is. Mr. Murphy above seems to have a handle on it.
You cannot be surprised that near term plans are being adjusted given that the Guadalajara meeting proposed a architecture 50 years out and absolutely no short term plan or gap filler with attainable steps. Also given that SpaceX is learning that human spaceflight is going to be more difficult than expected with upcoming delays for next years flights. The only thing that could save SpaceX Mars plans would be to forward an extremely short term and detailed plan that says exactly how and why and what are needed to get humans to Mars (and not just to plant a flag and not return).
Couldn’t Dragon do a flying re-entry, like the shuttle ? Why “doom” it to a ballistic re-entry like Apollo, Soyuz, Orion ?
When will we have our space elevator (so we don’t have to worry about re-entry) ?
1) because it is a capsule and not a lifting-body (aircraft like), and 2) probably never.
1) ok, Red Dragon then (not yet designed)
2) cynic !
Most “space capsules” generate a modest amount of lift by flying at an angle of attack which is achieved by offsetting the center of mass from the center of volume. This is essential for return from the Moon (or Mars for that mater) as a ballistic entry at those speeds would result in g-loads too high to be survivable. To my knowledge only the spherical Vostok and Mercury had a zero lift to drag ratios. Both these designs resulted in significant g-loads in the 8-10 range. My recollection from my grad school days is that a ballistic return at lunar return velocity (~25000 mph as opposed to ~17500 when returning from LEO) results in g-loads in excess of 20.
The examples you cite use ballistic re-entry as a fall back and very uncomfortable alternative to a piloted re-entry.
It is not the “piloting” (the vehicle control could be automated — maybe by “piloted” you mean “controlled on all 3 axes — pitch, roll and yaw”) that results in an entry that is not “ballistic” — it is the small mount of lift-to-drag ratio that does the trick. This is achieved by offsetting the vehicle center of mass from the center of volume. As such the capsule will fly at an angle of attack resulting in a more gradual entry which lowers the g-forces and the peak heating (total heat load however is increased somewhat due to the heating being spread over a longer period of time). By the way, Mercury had zero lift to drag and therefore flew a ballistic trajectory — Gemini and Apollo had a small amount of L/D as Soyuz does and Orion and Dragon 2 will. Reduced g-loads and peak heating rate occurs when the lift is oriented away from the Earth. For such vehicles (I don’t think this was possible on Apollo on return from the Moon as the g-loads for a ballistic re-entry at lunar return velocities would have been sufficient to kill the crew), a ballistic entry, as a back-up, is achieved by putting the vehicle into a constant roll rate thereby negating the lift effect on the trajectory. This is done to avoid the possibility (in the case that the vehicle attitude cannot be precisely controlled) of having the lift orientation being towards the Earth which would result in g-loads and peak heating WORSE than would occur on a “ballistic” trajectory. To the best of my knowledge, Soyuz has performed a ballistic re-entry three times in its history because of a failure of the Instrument and Propulsion Module to separate from the Descent Module at the proper time. In each of these cases the two modules separated later because of heating causing the remaining bolts to fail (by design). At that point, the guidance logic had faulted to a ballistic rather than a lifting re-entry. Had the two modules not separated due to the “by design” bolt failure, the crews on those three missions would have been lost.
Yes, Dragon can fly a lifting reentry since it’s not a sphere. Take a look at the history of capsules like Soyuz (similar shape) and you’ll see they also fly lifting reentries to reduce g-forces. They do this by offseting the center of gravity to one side a bit.
Ballistic reentry for Soyuz is a “contingency mode” in case of something like a guidance system failure, so in that case the capsule spins slowly about its axis of symmetry to cancel out the lift caused by the offset center of gravity.
“When will we have our space elevator (so we don’t have to worry about re-entry) ?”
When someone invents a material stronger than inter-atomic bonds. In other words, when someone invents a bulk material that is somehow not made of matter.
[Edit: For Earth, space elevators are materially impossible. With zero safety margin, you are on the very edge of what is materially possible on a short-scale. Hence well beyond what is possible over tens of thousands of kilometres. The closest we could get to a “space elevator” would be a down cable from an dynamically suspended orbital ring.]
“Couldn’t Dragon do a flying re-entry, like the shuttle ?”
It won’t be “like the shuttle”, since it’s not a spaceplane, but it does use a moveable ballast sled inside the capsule to allow the centre-of-balance to be shifted to allow a partial-lift re-entry profile.
“a moveable ballast sled “
That is something I hadn’t heard, assuming as I did that control was achieved with some sort of small thruster.
I assumed that the ballast sled is not active during re-entry. Ie, balance comes from the ballast sled, control comes from the Draco thrusters.
However, googling around for a ref gave me this throw-away line from SpaceX’s crew director, Garrett Reisman’s testimony to Congress: “a movable ballast sled allows the angle of attack to be actively controlled during entry to further provide precision landing control.”
http://science.house.gov/si…
(Can’t remember if you are the person who has trouble with Disqus’s horrible link-stealing. So:
science.
house.
gov/
sites/
republicans.
science.
house.
gov/
files/
documents/
HHRG-114-SY16-WState-GReisman-
20150227.pdf
Repeated parts are repeated in the link.
Yes, I’m the one tortured by the formerly-excellent platform known as Disqus, which eats links and which will not remember who I am, even though we have been hooked up for since Day One.
So. THANK YOU for the link and for preparing it so. And which, in the morning as usual, I’ll peruse it while watching the sun come up from the west coast of Florida.
(Which is fascinating in itself I have to say).
Do you mean they adjust trim during atmospheric entry? At first glance, that sounds insane. At second glance, maybe that’s something that’s just crazy enough to be a great idea.
The preferred centre-of-balance for re-entry is off-centre to allow lift, but during actual (land) landing, you want it as centred as possible.
That may be the extent of trim adjustment. OTOH, once you have a hammer…
There is no documentation to support such claims as “NASA didn’t want propulsive landings for Commercial Crew or Cargo” or “NASA doesn’t like penetrations through the heat shield” This was a SpaceX decision and not NASA’s. The cost and effort to qualify the propulsive landings is the likely explanation. Qualification tests for a parachute landing is easy. Just lift a flight weight boilerplate capsule high enough with an aircraft so that it reaches terminal velocity before parachute opening altitude. For the heavier propulsive landing capsule, the problem is that an helicopter can not lift a flight weight capsule high enough and there are issues with putting a live hypergolic spacecraft in an enclosed cargo aircraft. So the only way to fully test a propulsive landing capsule is to launch it. So faced with this reality and the little benefit that the capability has to other SpaceX endeavors, they decided to not spend the resources on a propulsive landing capsule
Well, Mr. Musk definitely said, ““The reason we decided not to pursue (powered landings) heavily is it would have taken a tremendous amount of effort to qualify that for safety, particularly for crew transport…” and he did go on to mention the ports in the heat shield. NASA does decide what work is needed for those qualifications. So NASA certainly had something to say about the matter.
You are correct to say we don’t know why those requirements were set at a level which makes them unrealistically expensive to satisfy. But I think it’s fair to say NASA set requirements at a level which SpaceX felt wasn’t worth trying to satisfy. That makes it both a NASA and a SpaceX decision.
So much doom and gloom being talked about this decision, yet to be honest if NASA was quicker to make decisions like this they would not be in the position they are today. This decision is almost certainly the result of more detailed internal SpaceX studies that have highlighted the fact the Red Dragon is probably a bit of a dead end, and a potential distraction from long term goals, this does not mean the long tem goals will also be delayed or shelved. this is simply about refining the architecture and finding the most efficient use of resources, I have no doubt there will be many more changes along the way but I also have complete confidence that SpaceX will land men on Mars and much sooner than NASA ever will.