50 replies on “InSight Makes A Perfect Landing On Mars”

  1. Never. Gets. Old.

    I could not be more proud of what these fabulous people have accomplished: Thank You!

  3. Nasa needs to just keep cranking out Phoenix lander copies and loading them up with new scientific instruments, just like this mission. It’s got a reliable, proven, economical lander design. Keep using it! Let’s put a drill on the next one!

    1. I wish they would launch one that just contained a bunch of ISRU experiments. MOXIE on the 2020 rover will be exciting but there could be so much more if they could copy+paste a successful design with different experiments.

          1. In spirit, MPL was. But I think what was meant is that the intended ’01 lander itself is now on Mars, at the Phoenix site–after some time in a box, some redesign, and significant changes in use of deck space and such.

    2. If they could keep the costs to Phoenix level or lower with this strategy, that would be great. However, InSight took longer and ended up twice as expensive.

      1. In a way, the higher cost is inherent to the way NASA selects missions. The budget for a mission is based on the cost of past, similar missions with a mandatory 30% reserve (which is always spent) tacked on. If you propose a mission which is a carbon copy of a previous one, and say you can do it for less because it’s been done before, you’re likely to get a nasty TMC (Technical, Management and Cost) review. Add the delay due to a botched instrument, and you get the most of the cost difference between Phoenix and InSight.

        1. There were some changes (e.g., higher res SSI), but Phoenix was largely a refly of MPL instruments on the ’01 lander that never flew (which in turn was basically the MPL lander with different solar arrays). Don’t know about any TMC reviews they ended up doing, but my impression was that being close to a carbon copy of MPL on an existing lander was one of the selling points of the proposal.

          1. Phoenix used a significantly different landing system from Mars Polar Lander. The failure review board found problems with the MPL landing system which almost guaranteed a crash, as well as some other problems that could have caused one. They definitely didn’t’ copy that…

            But as far as TMC reviews go, I’m not sure if Phoenix formally went through one. That’s mandatory for Discovery or New Frontiers missions, but it isn’t for directed missions (which includes flagships or almost all Mars missions.) The cost is reviewed, but the process is different.

            For Discovery and NF, it’s almost a one-way street, where it’s actually illegal to have significant feedback or replies to reviewer’s comments. (Replies to major weaknesses are allowed but highly constrained to things like, “We addressed that issue in the second paragraph on page 12.” If the proposals are limited to 15 pages to discuss a particular topic, allowing substantive replies wouldn’t be fair to competitors who stuck to the page limits.)

            For directed missions, there is feedback. The Europa Clipper and the Europa Lander concept, for example, went through multiple iterations of cost modeling. The concept study team had a chance to talk to the people doing the cost estimates and say things like, “no, that isn’t what we meant. If we did it that way, of course it would be insanely expensive.”

            For Phoenix, I’m not sure what was done. It was a competed mission, but the competition was constrained to the idea of re-flying a MPL-like mission. So I think the idea of saving money by flying very similar hardware was a given, and not subject to external reviews based on parametric cost models.

            I have had people tell me in no uncertain terms that there is no such thing as non-recurring costs on a planetary mission. Building two items costs twice as much as building one. I know that’s wrong, But it’s a sufficiently accepted idea that senior engineers can say that in a room full of other engineers and no one will challenge it (or, if someone does disagree, they aren’t likely to convince people.)

          2. Phoenix did go through a formal TMC, as a Scout mission. There may have been an MPL-like mission among the 30 or so competitors, but the final four of the Scout selection were PHX, an airplane, an orbiter, and an upper-atmosphere sample return. All 4 prepared a concept study report, presented it to the panel, and took and answered questions. But, having the M’01 vehicle or copies of the MPL instruments end up on Mars was not a given.

          3. Yes, I’m sure there were some important MPL lessons learned incorporated in the Phoenix lander’s avionics and contact sensing.

    3. There is a drill on this one. It’s a thermal sensor, designed to measure the heat flowing out of the planet’s interior. If it works (and I have some reservations about automated drilling) it will get down to five meters.

      What I really want to hear about is the solar panel deployment. That’s critical and I think that is something new. The ATK UltraFlex arrays (the low mass ones that fold out into a circle, as opposed to flat, rectangular, hinged panels) have been used before, but not on another planet’s surface. Then again, I’m the sort of person who keeps worrying about launches until well after payload separation… I don’t really think it’s over until the payload is in a safe state.

      As far as the landing system goes, I like this one and you’re right about it working well. I also like the airbag and bouncing approach, and that’s also proven on multiple landings. But it’s not viable for large landers. I definitely have doubts about the whole sky crane idea. I know that one justification is that there isn’t a practical way to land large rovers. But I was discussing that with a colleague when we had and afternoon off in Washington D.C. following a meeting. We were in the Air and Space Museum, and I just pointed at the Apollo lunar lander and said, “huh?”

      1. I was under the impression that the skycrane was needed to prevent the landing rockets from blasting dust everywhere and contaminating the payload?

        1. That was one of the issues, but MSL/Curiosity had, and Mars 2020 will have, all the scientific instruments on a rover. They do not depend on making measurements at the landing site. So using a sky crane to keep the landing site prestine isn’t a really solid justification. It is reasonable for the Europa lander concept, since that would involve a stationary lander. But for landing a Mars _rover_? I just don’t see that making sense.

          1. I tend to agree with your comments on the sky crane system. That said, perhaps the argument was made that the total mass required is less than a more straight forward approach with a rover on top of a lander. I don’t know if that is reasonable or not, I haven’t studied the problem. Also, with the rover on lander approach you do need ramps to get the rover off, so perhaps that was part of the argument. It’s always a tradeoff, and the sky crane has its own obvious risks. Lander legs (and airbags) provide some margin on the final descent velocity and sensing of the surface position. The sky crane winch provides the same, but it would seem that in this day and age you could land a rover as robust as MSL softly enough without it. Perhaps there was a control issue that was a concern that the winch alleviates. In any case they did it, it worked, and one hopes it will work again for M2020.

          2. That’s a fair summary. Putting a large rover on a more conventional lander would involve things like ground clearance, ramps, etc. That is, arguably, less mass efficient that a sky crane. How much less mass efficient isn’t clear, and how important that should be compared to cost and reliability is also not clear.

        2. That was one of the justifications but the significant one was because of the weight. The previous rover landings used air bags and Curiosity was too heavy for that landing technique. Thus was born the sky crane.

          1. The weight (or, more correctly the mass)? Really? So how do you explain the Apollo lunar landers? They put a much greater payload down without the need for a sky crane. The skycrane wasn’t born out of necessity. It was born out of a JPL desire to do something new and different, and by doing so, provide employment for their engineers.

          2. Because the moon is not Mars. On the moon, one can use thrusters to slow from orbital velocity to landing velocity, and spread that delta V out more or less linearly over the entire descent. Try that at Mars, and you’ll be coming through the atmosphere too fast and burn up. So you propose to shed almost all the velocity above the atmosphere and then gently descend 50 km? Try carrying that fuel load.

            If you buy into a heat-shield to drop much of the velocity, you would still need an enormous amount of fuel for thrusters to stop the remaining supersonic speed, hence parachute. Even with that, the probe is still coming in too fast, hence the thrusters. So that’s the state of the art. If you now scale it up to carry several tons of lander, then you’ll need a larger heatshield, and parachute.

            But launch vehicles like their fairing to be narrow, a handful of meters in diameter. That limits the size of the circular heatshield. No matter how you turn it, you can’t fit it in the cylinder fairing. So, that limits the heat shield diameter, which in turn limits the mass that it can effectively slow and protect.

            Larger, wider launch vehicles will help, but there is still a limit at a few tons of delivered mass, and NASA isn’t going to want to pay for more launch vehicle than would otherwise be needed.

            Your statement that JPL, or NASA, in the Discovery program would do “something new..to provide employment for their engineers” is both uninformed and spiteful. The only way to compete in the proposal process is to minimize risk, to show endless heritage and rarely to do something new in terms of the engineering – as evidenced by the selection of Insight, a mission that was sold on being largely a reflight of Phoenix.

          3. The saying I heard years ago with respect to Mars was “unlike landing on the Moon, the atmosphere on Mars is too thin to help you much, but too thick to be ignored”. Hence sky crane.

          4. The atmosphere of Mars has already helped quite a bit before the sky crane starts working. Before it fires, the spacecraft is subsonic and hanging from a parachute.

          5. Unfortunately, just about all of that is irrelevant. The technical issues you describe apply to any Mars landing, and you end at the point of parachute release. The sky crane is all about what happens after that. At that point, it’s all about a slow decent on rockets. That part isn’t radically different from landing on the Moon. And nothing about that requires lowering the lander on a cable while the rocket stage hovers.

            Writing “NASA isn’t going to want to pay for more launch vehicle than would otherwise be needed” is, in fact, more or less the problem. MSL launched on a Atlas V 541. If they had used a Delta IV heavy, it would have cost about $250 million more and would have allowed them to send almost twice the mass to Mars. How much did developing the sky crane cost? Since it was one of the big items in a $2.8 billion dollar mission, I suspect it may have cost well over $250 million. If so, paying more for the launch vehicle would have been the smart choice.

            As far as being “uninformed and spiteful” goes, I’ve worked with JPL for about a quarter century on four planetary missions and about as many concept studies. I think “informed and cynical” might be closer to the mark. It’s unfair to generalize about everyone at JPL. But I am quite sure there are lots of people there who just like solving difficult engineering problems. There are quite a few people there who are very good at writing requirements designed to make difficult engineering problems “necessary.” And most managers there feel an obligation to bring in projects, in order to pay the people they manage (e.g. the people who like to and are good at solving complicated engineering problems. Maybe connecting those things is cynical, but that doesn’t make in automatically wrong.

            The example of Discovery missions, InSight and Phoenix is misplaced. I was complaining about the sky crane and that’s part of MSL/Curiosity and Mars 2020. Discovery missions are cost caped and competitively selected. For a mission like that, JPL can’t go wild with things like sky cranes. The proposals wouldn’t be selected. MSL and Mars 2020 are directed missions with no specific cost cap (at least not in the sense of a Discovery, New Frontiers or Explorer mission.) They also don’t go through formal Technical, Management and Cost reviews. (There are reviews, but they are structured differently, and not used as a up/down criteria for selection.) Those are the missions where JPL has a habit of making things more complex than I consider necessary, and those are the missions where costs tend to get out of control.

          6. Yes really. Well at least according to the JPL website:

            https://mars.jpl.nasa.gov/m…

            Comparing the LEM with the Mars landers is not a fair comparison. They were designed with a set of different constraints such as launch mass, cost and so on.

          7. I know the official justification for the sky crane is mass. My point is that I don’t find that justification convincing.

      3. If we are going compare Mars with lunar landings, what about a lunar rover? don’t have to wait for a two year interval and months of travel time. Would be interesting to examine materials at the Apollo landing sites (aw c’mon, US govt can excuse a NASA closeup mission) or go into one of those polar craters and examine soil more extensively instead of quick look at a plume cloud as done on LCROSS.

        1. I wouldn’t complain, but NASA funding for lunar missions has gone back and forth. Primarily based on whether or not human spaceflight is talking about landing people there. But the funding has never been very large, and the Moon and Venus seem to be the perpetual losers in Discovery and New Frontiers selections.

          On the bright side, someone’s planing to fly a lunar rover. Chang’e 4 launches on December 7 (UTC) and it’s got a copy of the Yutu rover. I’m not sure, but I think some of the private (formerly X prize) projects also have a rover component. Some of them are due to launch real soon now.

    4. This is the end of the line for the Phoenix/Insight lander design. The spare parts for the Phoenix lander was used to build the Insight lander. It is not likely that new parts can be sourced as they are obsolete by industrial standards.

      Cost reduction is not possible for a boutique spacecraft design that takes more than a decade from start to finish. NASA also have a bad history of using museum grade electronics that is no longer manufactured or supported by industry.

      Until someone can get something on Mars with a payload of greater than the 900 kg, there will be no deep drilling on Mars. Not likely to be NASA.

      1. What would you call deep drilling and what would the purpose be? InSight plans to drill five meters down, to measure the geothermal heat flux. If you think deeper drilling is needed, I might agree. But you would have to explain why it is useful or productive.

        1. NASA does not have a drill with Insight. What is got is the HP3 burrowing probe from DLR of Germany.

          It might get to 5 meter depth. I think it will encounter something unlike loose regolith after the first meter. We shall see.

          Deep drilling should get to a depth of about 100 meters. To get geological samples at various depths at various locations along with deploying seismic and thermal sensor packages in the drilled holes. Ideally the drill rig should be manned by real roughnecks.

          3. I said (in a different comment) that I have reservations about automated drilling… So having a crew would probably be a good idea. I’m also not convinced you need a 100 meter hole for thermal and seismic work. But for stratigraphy, especially in the norther layered terrain, that would be fantastic. Actually drilling deeper than 100 m might be better.

          4. Limiting initial drilling to 100 meters depth is to avoid the need for a drill rig that can not move by the initial rovers.

            Drilling deeper than 100 meters should be after some test drills to 100 meters. Then you can send a much bigger drill rig designed with the operational experience of the initial drill rigs.

            Deep drilling probably required active seismic probing of the subterranean strata prior to any drilling campaign.

            In some ways drilling on Mars is similar to drilling in the High Arctic.

  4. Thanks to JPL for designing it, Lockheed for building it and ULA for launching it. There’s a Mars dream team if there ever was one.

    1. Let’s not forget to credit the Europeans, who built most of the scientific instruments. But perhaps we should wait for the results before crediting them; the landing is a solid JPL/Lockheed achievement and that’s what we’re celebrating today.

  5. Well done NASA! But depressing to read the literally HUNDREDS of comments on ‘social media’, YouTube etc screaming ‘Fake!’ Someone punch those morons. Or maybe upgrade the education system…?

    1. That’s one of the joys of living in a big country. There are bound to be hundreds of people who believe just about anything and who spout off their opinions when ever they get a chance. There are also people who can’t imagine astronauts walking on the Moon, and the fact that astronauts have done so doesn’t change their minds. I just put them in the same category as people who consider buying lottery tickets to be a sound retirement plan. Nothing I can say will change their minds, trying to do so will just make me depressed, and I really don’t need that.

    2. I give NASA props for “creating” all the people who decry NASA photos, videos, and claims as fakes or products of the fertile mind fo Stanley Kubrick, who’s secretly still alive and still producing NASA promo material.

      Seriously, NASA has in the last few decades unleashed a flood of amazing imagery and science from probes and landers scattered across our solar system. As a wee lad I was gobsmacked by images of the Moon snapped from inside the CM in transit to the Moon. or the images of men on the Moon. Compare those noisy, lo res images with what we get now. The visible fruits of the advance of technology are stunning.

      I only hope that these pics are as inspiring to kids today as they were for me in the late sixties and early 70’s. What I saw drove me to become a scientist.

      1. Seeing as we often seem to think alike on many issues; it nevertheless puzzles me why you would down-vote my posts?!

  6. Just watched the NASA briefing on the InSight mission. Never heard Bridenstine talk before. I was impressed. Seems like a good guy.

    1. And yet the comments sections on YouTube and ‘social media’ endlessly troll the guy and denigrate him. Disappointing…

  7. Does anyone know how the Insight lander/system will actually be able to determine the composition and thickness of the Martian crust, and detailed analysis of its interior? Hoping we have some geologists here who have might be able to chime in. My understanding is that Insight’s seismometer is a completely passive device (i.e., listening for seismic events and signals). Now, that is all well and good…but in order to determine inner composition, we would need to measure the propagation velocity of the seismic waves (e.g. P-waves and S-waves). In order to do that, I have to assume we need to know the exact timing and location of a seismic event (in order to calculate wave velocity). How the heck are they going to be able to determine the time and location of the initiating event, itself, in order to calculate body wave propagation speed through the planet’s interior? I assume I am missing something obvious, here.

    1. With one station and no knowledge of the source location, you can’t do a direct inversion. It’s more complicated than dividing distance by time to get the sound speed. But you do get some information. For example, the difference between the P and S mode arrival times. I found one paper on ellipticity (polarization) of the waves and near surface properties. From things I’ve seen presented at conferences, I think they are also expecting to get information from the direct waves and also reflections off the crust-mantle and/or mantle-core boundaries (which would probably be very weak signals compared to the direct path.) That’s all pretty model-dependent and non-unique, which means they’ll need to measure many events and do a parameterized best fit. And that means a very sensitive instrument, since it’s not like they are going to be handed a whole lot of magnitude 7.0 marsquakes.

      1. Thanks for the detailed reply fcrary. And certainly I recognize that determining inner crust/mantle composition requires complex analysis…however, as a fundamental bare minimum, the P and S wave speeds must be determined. Without multiple seismometers (located across hemisphere of Mars), there is no way to determine timing and source of initiating seismic event, and thus no way to determine speed of body and surface waves. At the Insight press conference, the PI discussed the need to determine composition and depth of crust. Would I be correct in assuming that the single seismometer / Insight mission will only be able to provide indirect information that may serve to put a finer limit on the constraints used in the model for Mar’s outer crust, but it will not provide direct, definitive values?

        1. I suppose you could call it an indirect measurement. It definitely will not be a direct inversion of the measured signals. But I’m inclined to call it more than an indirect constraint.

          You could, for example, take a horribly simplified model of the interior, assuming spherical symmetry and three, uniform layers (crust, mantle and core) and use it to predict what the signal from an even would be. That’s 8+n free parameters (P and S mode speed in each layer, the radius of the core and the mantle, and the range to n events.) You can vary those parameter and find the values which best fit the data. You’d need at least two numbers per event (more data points that free parameters is sort of mandatory…) But that’s not impossible if they can get reflections off the crust-mantle boundary. The result would be uncertain, and assuming three homogenous layers is pretty unrealistic for a real planet. But it’s more than nothing.

          There are also other measurements the mission will provide. The radio science experiment will give the polar precession rate, and that depends on the moment of inertia of Mars (and therefore the mass distribution within the planet.) The geothermal heat flux is also a constraint on the models. Having multiple stations would definitely be better (I think just three would do), but that’s not as easy to do on Mars as it is to do on the Earth.

    2. I wonder if they will be able to detect some of the impact events from the Mars 2020 landing, assuming it will be similar to MSL which dropped several pieces on Mars at various velocities. Shortly after separating from the cruise stage the MSL entry vehicle released two 75 kg tungsten blocks. Four large impact sites were later observed about 80 km west of the Curiosity landing site. Two of those impacts made craters 3-5 meters wide, which are believed to be the tungsten blocks. The other two impacts along with several smaller impacts are believed to be the cruise stage which presumably broke up during reentry. Assuming Mars 2020 sheds similar ballast I would think at least maybe the tungsten block impacts could be detected by Insight.

      Then just prior to parachute deployment the MSL descent stage dropped six more tungsten blocks, although these were smaller at 25 kg each, and being released at much lower altitude and speed than the 75 kg blocks their impact may be too weak to detect. Also after releasing Curiosity the skycrane flew off and crashed a few kilometers away. But that would presumably be a pretty weak impact also. Of course all of this assumes that Insight is still functioning when Mars 2020 lands.

      I wonder if a future orbiter could carry an instrument that detects meteor ionization trails, which might help them correlate observed meteors with detected impacts.

      1. Jezero crater is about a fifth of the way around Mars from the InSight landing site in Elysium. I don’t think that’s viable for a 75 kg mass hitting at 6 km/s. Now, if you could target Elysium, and get a hit a few kilometers from InSight, that might work. Mars Reconnaissance Orbiter could image the site and give the range, and the timing of the event would probably be known with reasonable accuracy. But I strongly suspect the Mars 2020 project won’t be interested in making compromises in their critical sequence. People get nervous about landings and usually don’t want to do anything that isn’t exactly what they’d like to assure success.

        The idea of imaging meteor trails is interesting. I’m not sure it would help for individual events, but I can see the statistics helping. With a impactor flux and size (or kinetic energy) distribution, you could say something about the amplitude/range distribution of seismic events. At the moment, the impactor flux and size distribution is mostly theoretical extrapolations from the Earth.

Comments are closed.