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Philae has landed

bbc.com

31–40 of 309 posts

Re: Philae has landed

#31
post #21

Hope this isn't a dumb question, but how does Philae stay put? If the gravity strong enough to keep it on the surface? Also, as the comet nears the sun and parts of the comet start flying off, is there a threat of Philae getting swept along with it?

Gravity is very weak, it harpooned itself into the surface. The comet doesn't come very close to the sun, only around 1.2AU or so.

Re: Philae has landed

#32
post #17

Anyone knows where i could find some info about the software stack this kind of probes are being built with ? Languages, programming methods, patching methods,os, runtime, etc. I'm really curious to know how different it is from the web or enterprise development worlds.

Start with vxWorks.

Re: Philae has landed

#33

Amazing job! This might be a silly question but are their any ideas as to the actual real world benefits we could see from this? The director-general of the ESA said "This is a big step for human civilisation" so I presume there is some idea of what they expect to gain from this mission? Edit: Thanks for all the replies! I'm at work now but will take a look at them this evening.

Ice from Jupiter-class comet supposed to be what seeded Earth with water billions of years ago. Want to see what chemicals are there etc.

I get that part but what tangible benefits will I/humanity see from it? Or is it more of a case of gaining more knowledge about how the Universe works in the hope that that knowledge combined with other knowledge may lead to something eventually?

Re: Philae has landed

#34
post #17

Anyone knows where i could find some info about the software stack this kind of probes are being built with ? Languages, programming methods, patching methods,os, runtime, etc. I'm really curious to know how different it is from the web or enterprise development worlds.

There is not much to find, but apparently, they do software updates over the "air": http://blogs.esa.int/rosetta/2014/03/28/software-upgrade-at-...

Re: Philae has landed

#35

Amazing job! This might be a silly question but are their any ideas as to the actual real world benefits we could see from this? The director-general of the ESA said "This is a big step for human civilisation" so I presume there is some idea of what they expect to gain from this mission? Edit: Thanks for all the replies! I'm at work now but will take a look at them this evening.

I am sure that companies like Planetary Recources (and anyone who wants to make refueling in space possible) will greatly benefit from the discoveries made during this mission.

Re: Philae has landed

#36
post #17

Anyone knows where i could find some info about the software stack this kind of probes are being built with ? Languages, programming methods, patching methods,os, runtime, etc. I'm really curious to know how different it is from the web or enterprise development worlds.

Like other embedded systems, spacecraft computers use real-time operating systems (RTOS) and languages:

* The Rosetta probe ultimately runs SCL (Spacecraft Command Language) [1], a COTS spacecraft programming language developed for sale to the military [2]; SCL is based on the syntax of Ada 83, which has a long legacy in spaceflight and other real-time applications (e.g. Boeing 777) [3]. However, what are known as Flight Control Procedures (uploaded commands), are written using another language and transformed and compiled into SCL in a two-step process that involves XSLT [1]. On-board Control Procedures, which are procedures the probe decides on its own to run, and handle tasks such as receiving FCPs and sending back telemetry, are written in SCL [1].

* The Mars rover Curiosity is programmed in C and uses the VxWorks RTOS [4], which is very much like many commercial embedded systems. It has about 2.5 million lines of code, much of it autogenerated. Curiosity's predecessors, Spirit and Opportunity, used the same software stack, as did their predecessor, Sojourner [8].

* The Voyager probe, which has now left the solar system and entered interstellar space, uses "...interrupt driven computer[s], similar to processors used in general purpose computers with a few special instructions for increased efficiency. The programming is a form of assembly language." [5]

* The Space Shuttle was programmed in a custom language called HAL/S (High-order Assembly Language/Shuttle) [6], as was the Jupiter probe Galileo [7]. The language is descended from PL/I and its compiler is written in a subset of PL/I called XPL.

[1]: http://www.rheagroup.com/wp-content/uploads/2014/01/SpaceOps...

[2]: https://www.sra.com/scl/

[3]: https://en.wikipedia.org/wiki/Ada_(programming_language)

[4]: http://programmers.stackexchange.com/a/159638

[5]: http://voyager.jpl.nasa.gov/faq.html

[6]: https://en.wikipedia.org/wiki/HAL/S

[7]: https://en.wikipedia.org/wiki/Galileo_(spacecraft)

[8]: http://programmers.stackexchange.com/a/159687

Re: Philae has landed

#37

Amazing job! This might be a silly question but are their any ideas as to the actual real world benefits we could see from this? The director-general of the ESA said "This is a big step for human civilisation" so I presume there is some idea of what they expect to gain from this mission? Edit: Thanks for all the replies! I'm at work now but will take a look at them this evening.

Real world benefit? In 20 years, we move the production capacity of China to space, and everyone, anywhere on the Earth, has the ability to order a product, remotely assembled on our comet moon, for direct delivery.

sigh A man can dream.

Re: Philae has landed

#38

Amazing job! This might be a silly question but are their any ideas as to the actual real world benefits we could see from this? The director-general of the ESA said "This is a big step for human civilisation" so I presume there is some idea of what they expect to gain from this mission? Edit: Thanks for all the replies! I'm at work now but will take a look at them this evening.

The lander's mission is:

> elemental, isotopic, molecular and mineralogical composition of the cometary material, the characterization of physical properties of the surface and subsurface material, the large-scale structure and the magnetic and plasma environment of the nucleus

Amongst other things, they'll be looking for complex organic molecules.

Re: Philae has landed

#39

Earlier quoted context omitted.

Ice from Jupiter-class comet supposed to be what seeded Earth with water billions of years ago. Want to see what chemicals are there etc.

I get that part but what tangible benefits will I/humanity see from it? Or is it more of a case of gaining more knowledge about how the Universe works in the hope that that knowledge combined with other knowledge may lead to something eventually?

[deleted]

Re: Philae has landed

#40
post #17

Anyone knows where i could find some info about the software stack this kind of probes are being built with ? Languages, programming methods, patching methods,os, runtime, etc. I'm really curious to know how different it is from the web or enterprise development worlds.

This article is a classic, coming up on 20 years old, specifically about how differently the shuttle software team was from the dotcoms. http://www.fastcompany.com/28121/they-write-right-stuff

No idea how relevant it is today, or any differences between the shuttle team and whoever's building/built the software for this lander, but it's definitely worth a read.

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