Mars Reconnaissance Orbiter views Schiaparelli landing site • Hacker News Board

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#31

Post by mturmon » Fri, Oct 21, 2016, 7:02 PM UTC

Questions have come up about the landing strategy of the Schiaparelli lander. It uses a Doppler radar to get position and velocity, time deployment of parachute, and calibrate thrust for retro-rockets. The best references I was able to find are these:

http://exploration.esa.int/mars/47852-entry-descent-and-land...

http://solarsystem.nasa.gov/docs/Bayle_ExoMars_EDM_Overview-... (solid, is undated, seems old and nonspecific in some cases)

https://solarsystem.nasa.gov/docs/7B.1_Lorenzoni_ExoMars%202... (from 2013, more detail)

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#32

Post by jellicle » Fri, Oct 21, 2016, 7:03 PM UTC

LunaSea wrote: post #27

Once again, billions of euros are put into use for what is essentially scientific curiosity instead of trying to solve the very real problems Europe is facing. I love astronomy and space exploration but the amounts of money wasted into it rather than other problems with a high priority is staggering.

Yeah! When has exploring ever benefited anyone! No more exploration!

The mission cost the citizens of Europe and Russia a bit over 1 Euro per person.

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#33

Post by nixos » Fri, Oct 21, 2016, 7:06 PM UTC

dr_zoidberg wrote: post #26

nixos wrote: post #19

Earlier quoted context omitted.

Yes, the point wasn't the lander but the _landing_ . If the landing works, they can try an expensive rover in 2020. Now, they can fix what they think broke, but they're never sure until it (fails to) land.

Or if it lands they can say "see? we learned to land with the crashed Schiaparelli, so it was good sending it in the first place". But a succesful landing would've been better, now they may face a few objections arising from the failure.

>Or if it lands they can say "see? we learned to land with the crashed Schiaparelli, so it was good sending it in the first place"

Failures may not be bad, but they're still failures.

Apollo 1 was a failure. Sure, it helped NASA make future spaceflight safe, and may have saved more lives in the long run (Apollo 13 makes it even) , but it didn't accomplish its goal.

Especially that a successful lander is a reality check. We did it once and we can do it again.

A failure doesn't say anything. It could have been a stuck thruster, it's fixed, and then the crush-zone is found to be defective.

That's why first (and test) flights tend to be cheaper and failure prone.

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#34

Post by mturmon » Fri, Oct 21, 2016, 7:07 PM UTC

dr_zoidberg wrote: post #29

protomyth wrote: post #24

Earlier quoted context omitted.

I'm waiting for the day where someone can tell their rover to drive / fly over and find out what the heck happened.

Opportunity is not so far (it's actually inside a crater nearby I think), but it'd take months to get to place, and there may not be enough scientific value in doing so just to see the charred remains of Schiaparelli. But who knows, it's so over it's expected mission life that maybe someone goes "f * it, let's go take a look".

Opportunity tried to see the descent, but it did not work: http://www.planetary.org/blogs/emily-lakdawalla/2016/1019152...

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#35

Post by LunaSea » Fri, Oct 21, 2016, 7:15 PM UTC

pavlov wrote: post #30

LunaSea wrote: post #27

Once again, billions of euros are put into use for what is essentially scientific curiosity instead of trying to solve the very real problems Europe is facing. I love astronomy and space exploration but the amounts of money wasted into it rather than other problems with a high priority is staggering.

The EU has a population of over 500 million. For a program like this (assuming it's all from public funds), each citizen paid on average less than a cup of coffee costs at Starbucks. It's real money, but what pressing pan-European problem could you really solve with such a tiny budget?

Look at the economical situation of countries like Greece and Spain. That would be one starting point.

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#36

Post by david-given » Fri, Oct 21, 2016, 7:15 PM UTC

Aqua_Geek wrote: post #3

> Estimates are that Schiaparelli dropped from a height of between 2 and 4 kilometres, therefore impacting at a considerable speed, greater than 300 km/h. Ouch. It will be interesting to read the results of the investigation as to why the landing thrusters turned off prematurely.

According to the landing sequence...

...the lander was supposed to detach from the aeroshell at about 1km up. So if it fell from 2 to 4km up, that implies that it detached too early.

This article:

https://spaceflightnow.com/2016/10/20/last-data-from-schiapa...

...says that the telemetry shows that the engines did fire, for at least a few seconds.

My uninformed hypothesis: the lander detached early for some reason, and started falling. As it approached the ground, the radar saw the ground coming, and it fired the engines for the final braking. But because it had been falling so far, it was now going too fast for the engines to stop it in time, and it hit the ground hard. (Mars doesn't really do terminal velocities.)

It says they have 600MB of telemetry. That's quite impressive.

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#37

Post by LunaSea » Fri, Oct 21, 2016, 7:15 PM UTC

jellicle wrote: post #32

LunaSea wrote: post #27

Once again, billions of euros are put into use for what is essentially scientific curiosity instead of trying to solve the very real problems Europe is facing. I love astronomy and space exploration but the amounts of money wasted into it rather than other problems with a high priority is staggering.

Yeah! When has exploring ever benefited anyone! No more exploration! The mission cost the citizens of Europe and Russia a bit over 1 Euro per person.

And how much return did the citizens of Europe and Russia get for this investment?

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#38

Post by trothamel » Fri, Oct 21, 2016, 7:16 PM UTC

dr_zoidberg wrote: post #28

ythl wrote: post #23

High visibility European space missions seem to have catastrophic failures a lot

Mmmm... not so sure, the Huygens probe was a high visibility ESA mission[0] and worked fine. [0] https://en.wikipedia.org/wiki/Huygens_(spacecraft)

Well, except for one of the two data channels being lost, and a design that had a major flaw that was overcome only with heroic engineering effort (and a major mission redesign). Both of these are discussed in the wikipedia page.

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#39

Post by david-given » Fri, Oct 21, 2016, 7:18 PM UTC

jcoffland wrote: post #6

Trial run? Sounds like the spin machine at work to me. I wonder what a trial run to Mars costs these days.

Schiaparelli's official name is the Entry, Descent and Landing Demonstrator Module --- EDM for short. It only had a few basic science instruments and enough battery to last for a few days. It really was just an experiment.

Re: Mars Reconnaissance Orbiter views Schiaparelli landing site

#40

Post by beamatronic » Fri, Oct 21, 2016, 7:20 PM UTC

protomyth wrote: post #24

beamatronic wrote: post #13

It is so bad ass that when we have a question about something that happened on another planet we can just point one of our other robots' cameras at the site!

I'm waiting for the day where someone can tell their rover to drive / fly over and find out what the heck happened.

We have proven designs for Mars rovers, and a proven delivery system. The R&D has been done, the infrastructure is in place - why don't we send some more? We should be able to make incremental updates and constantly improve the rovers capabilities.