How to Land on Mars | Hacker News Reader

How to Land on Mars

nytimes.com

245 pointsdigital5548 comments

This reminds me of when Curiosity landed years ago. It was a really cool event and I remember watching it on my Xbox. I think there was a special app to use to watch the event at NASA live. It was one of the tensest things I'd ever seen. I hope kids of all ages over the world get to experience something like this if you're interested in science.

I had the fortune of watching the landing broadcast live (from JPL, that is, not from Mars of course) at NASA Ames. That was really exciting, to see something like this with other people who cared just as much.

I vividly remember a sense of total awe watching it, thinking here we are, watching a broadcast from inside the JPL - as it happens! - of a craft in a totally new, complex method of landing after travelling and being guided millions of kilometres.

What struck me in particular was the sense of wonder at being able to see that first image of the wheel - transmitted across the globe live as they received it.

Such a privilege and accomplishment.

https://www.youtube.com/watch?v=bGD_YF64Nwk - live coverage of InSight landing on the NASA JPL channel, started November 26, 2018 at 19:00 UTC, touchdown at around 20:00 UTC

When I was a kid I remember watching on PBS as they covered pictures of Jupiter getting transmitted from Voyager 1 as it flew by. It was really exciting. The pictures didn't come that quickly but it felt really exciting to watch a TV program with the scientists from NASA.

Successful touchdown confirmed!

Final approach: https://www.youtube.com/watch?v=bGD_YF64Nwk&t=54m10s

So smooth, hardly noticed we were landing... I guess 95% of the HN population came along for the ride: https://mars.nasa.gov/participate/send-your-name/insight/

I wanted to know a little more detail about why the broad equatorial plain Elysium Planitia was chosen as the landing place. Found this article but just curious if there is any more detail about the location or selection process?

Elysium Planitia, a flat-smooth plain just north of the equator makes for the perfect location from which to study the deep Martian interior.

Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, is designed to study the deep interior of Mars. The mission seeks the fingerprints of the processes that formed the rocky planets of the solar system.

Its landing site, Elysium Planitia, was picked from 22 candidates, and is centered at about 4.5 degrees north latitude and 135.9 degrees east longitude; about 373 miles (600 kilometers) from Curiosity’s landing site, Gale Crater. The locations of other Mars landers and rovers are labeled.

InSight's scientific success and safe landing depends on landing in a relatively flat area, with an elevation low enough to have sufficient atmosphere above the site for a safe landing. It also depends on landing in an area where rocks are few in number. Elysium Planitia has just the right surface for the instruments to be able to probe the deep interior, and its proximity to the equator ensures that the solar-powered lander is exposed to plenty of sunlight.

https://www.nasa.gov/image-feature/jpl/pia22232/insight-s-la...

Here’s the paper they published about landing site selection (7.5MB PDF): https://spiral.imperial.ac.uk:8443/bitstream/10044/1/48751/2...

Table 3 on page 20 of the PDF is a good summary; their main constraints were latitude, elevation, slope (flatness) and rock abundance.

Interesting link at the end of the article about a mini helicopter NASA's sending along with the Mars 2020 mission - https://www.nytimes.com/2018/05/11/science/mars-helicopter-n...

In July 1997, I was temporarily unemployed and in the unemployed doldrums. I remember watching the day by day updates on Mars Pathfinder. Matt Golombek was the Pathfinder lead and face on TV (CSPAN?). He's a bit presuming but he quickly became my geek hero. Good to see that he's a lead on InSight, twenty years later.

I have not been following space exploration in depth so forgive my ignorance on the subject:

1. How long did the trip take ?

2. How many times have "we" (the world) tried and failed?

3. How many times have "we" successfully landed ?

4. Is this "ship" able to return to earth.

Thanks!

1. Six months.

2. This is the fifth success, out of thirteen attempts, over sixty years.

3. There have been five successful landings.

4. No.

There have been more successful landings on Mars:

Viking 1

Viking 2

Mars Pathfinder

Spirit

Opportunity

Phoenix

Curiosity

InSight

And all of the above are JPL projects! The only thing you left off the list is the USSR's Mars landers: https://en.wikipedia.org/wiki/Mars_program (Proud JPLer here, although I haven't worked on any Mars stuff.)

Do you still do any occult ceremonies before launching stuff?

Peanuts. (Wait, that's for EDL, not for launch.)

I didn't include the Soviet Mars landers because the most successful of the bunch only worked for 20 seconds on the Mars surface. They had better luck with Venus.

https://en.wikipedia.org/wiki/Mars_3#Entry,_descent,_landing...

And I believe all were built by Lockheed Martin?

This is not correct. I believe there have been eight successful Mars landings: Viking 1 and 2, Mars Pathfinder, the two Mars Exploration Rovers (Spirit and Opportunity), Phoenix, the Mars Science Laboratory (Curiosity), and now this one (InSight).

Failures include (going off of a list on Wikipedia) 2MV-3 (Soviet probe that never left Earth orbit; not sure if you want to count this or not since it didn’t fail during landing), Mars 2, Mars 3 (landed successfully but failed within minutes), Mars 6, Mars 7, Mars Polar Lander, Beagle 2 (landed but solar panels failed to deploy), and Schiaparelli.

So I think there have been eight successes and eight failures, if you only count probes intended to land. Notably, all eight successful landers so far have been launched by the United States.

1. About 6 months https://www.google.com/search?q=insight+launch+date&oq=insig...

2. Out of ~50 missions, about 20 have failed. https://en.m.wikipedia.org/wiki/List_of_missions_to_Mars

3. About 8 successful landings https://en.m.wikipedia.org/wiki/Mars_landing Curiousity was by far the 'coolest' and still astonishes me that we pulled it off. https://youtu.be/h2I8AoB1xgU

4. No.

All true.

To elaborate slightly on (4), Mars 2020, which is scheduled for launch in summer 2020, will have the ability to gather 20 samples into a sample cache, and drop the cache container off, for a possible future return pick-up. So, it's getting closer.

I was just reading an article before the landing that mentioned the number of attempts vs success. I couldn't find it, but found this: https://en.wikipedia.org/wiki/List_of_missions_to_Mars

After Curiosity's "helicopter drop but on Mars" style landing normal landings like this seem boring by comparison. I can't believe that was 6yr ago.

I wonder why the helicopter drop was necessary then but not now?

The sky crane maneuver (as JPL called it) was necessary because if they descended propulsively to the surface, it could kick up a huge dust cloud. That dust could land on the rover and damage the instruments. See this awesome video: https://www.jpl.nasa.gov/video/details.php?id=1090

I think there was also concern about the hydrazine-fuelled landing rockets contaminating the site and instruments.

Listening for quakes is not an activity which will be impacted by the surface being gunked up.

The audacity of that.

I like to think some manager saw the army drop a humvee from a blackhawk and asked "why can't we do this, but on Mars?" and nobody came up with a good enough answer so they did it.

Edit: Why is this comment unacceptable?

I always just figured Wile E. Coyote was on staff at the time and had his ACME catalog handy.

Plus this awesome video: https://www.youtube.com/watch?v=gZX5GRPnd4U

I was standing next to one of the engineers who wrote the software for the landing while we were watching on the big screen at Twitter. A few moments after it landed he announced that his code worked and was being deleted to make room for surface operations code.

That's one of those cool things that never gets thought about outside the people directly involved. "Why keep the code required for landing readily available permanently, since it'll never ever need it again." That's one of the aspects that I enjoy about programming Arduino devices. I'm so spoiled to essentially unlimited memory on desktop/laptops (in comparison) that writing code to fit into extremely limited finite amounts of memory becomes challenging in a fun way.

I always wonder if there was any video released of the sky crane tests on Earth. I have to imagine they were done at some point, but I never saw it.

I think it's because Curiosity was a rover and Insight is only a lander. A lander can have rockets on the bottom that slow its descent, but a rover can't, as then the wheels won't work. So the "helicopter drop" puts the rockets on a platform far above the rover (so the exhaust won't damage it) and then it flies away once the rover is on the surface.

Spirit/Opportunity were both wheeled rovers, and both landed with something under them; they had ramps that unfolded after landing, and the rover then proceeded to drive off the ramp onto the surface. So I don't think putting things under the wheels is necessarily a non-starter.

(But those rovers, IIRC, did a bounce-and-roll-to-a-stop style landing.)

The difference is that those rovers are a small fraction of the size and weight of Curiosity - the latter probably couldn't have survived a bounce-and-roll.

Curiosity was too heavy for the airbag-style landing: https://en.m.wikipedia.org/wiki/Mars_Science_Laboratory#Entr...

I'd guess: Insight isn't a rover and thus less sensitive to a bad landing/getting stuck.

Weight. Curiosity weighs over twice as much as Insight and needed a special heavy lift landing device.

Insight doesn't need it, so no reason to spend the money on it.

As I recall there was also something about the complexity of having the rover drive off the landing platform which was to be avoided. It would have been several feet of the ground and needed to get down.

Extraordinary claims...

Surfaces visited by Humankind (or by robotic ambassadors) 2018 - https://imgur.com/a/v9Pc5Qz

This is a pretty interesting poster. It shows just how similar the surface of these alien worlds look. The image of Earth is the obvious "one of these things is not like the others".

Venus, Mars and Titan look a bit more hospitable than the rest. The Mars one looks like somewhere you could actually encounter on Earth.

Nice poster. Looks like it's time to land some rovers on Jupiter's moons.

They did it a few minutes ago.

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