A short question!

[Beja]

How can outer space crafts navigate its routes through the planets without GPS?

 

[Star-Dust]

Short answer: they use the space road map

 

[Sandman]

As strange as it seems, this site does not contain all the knowledge of the world. Some questions are better to ask elsewhere.

First result on Duck Duck Go for

How can outer space crafts navigate its routes through the planets

How do space probes navigate large distances with such accuracy and how do the mission controllers know when they've reached their target?

www.scientificamerican.com

 

[LucaMs]

How can outer space crafts navigate its routes through the planets without GPS?

Looking through the windshield ?

 

[rabbitBUSH]

First result on Duck Duck Go for

its interesting to stop at the end of each sentence in that article and think about what job exists out there that one never thought (or bothered to) exists to perform that function/gather that data and so on etc....... [[for instance, someone/people occupy jobs collecting data that feed construction of those interplanatary grids]] blah blah . . .

 

[eps]

You need 4 dimensions to navigate in space, as relying on something being there relies on it being there at that point in time..

 

[Beja]

You need 4 dimensions to navigate in space, as relying on something being there relies on it being there at that point in time..

I select this as best answer.. Thank you eps
The space vehicle has multiple sensors.. it can lock to the sun and a few planets as objects.. it knows where the planets are relative to each other at any (time), then calculates its position in space. But it will not just know its position and go to Christmas, but it will contentiously adjust it's path to the destination.

 

[agraham]

The space vehicle .. calculates its position in space.

Actually this is usually done back on earth and any course changes are uplinked as commands to the space craft.

but it will contentiously adjust it's path to the destination.

Not at all. Course corrections are done only very occasionally and only when necessary. The availability of maneuvering fuel is usually what determines the usable life of a space craft and it is eked out as much as possible.

 

[ilan]

Actually this is usually done back on earth and any course changes are uplinked as commands to the space craft.

this is exactly what I was thinking.
the spaceship is communicating with the team on earth and getting the route back.

 

[agraham]

As a further comment in case anyone is interested but doesn't know it - spacecraft usually have very limited computation capacity which is the reason a lot processing is done on earth and commands uplinked to the craft. Space qualified processors have to be very reliable in a high radiation low power environment and so are built on large geometry semiconductor processes and are clocked at what would be regarded as very low frequencies for a general purpose processor here on earth.

An interesting exception is the Ingenuity helicopter, which because it was intended as a very short life experiment, used a commercial off the shelf Qualcomm 801 processor running Linux and may thus have much more processing capability than the Perseverance rover itself which uses an aged Power PC part.

The Perseverance rover runs on processors used in iMacs in the 1990s

The processor in the Perseverance rover on Mars is similar to the one that powered the colourful iMacs from the late 1990s, with some added radiation shielding

www.newscientist.com

 

[agraham]

Sorry, the link above may be paywalled - here's the gist of it.

Perseverance is running on none other than a PowerPC 750, a single-core, 233MHz processor with just 6 million transistors that’s most famous for powering the original “Bondi blue” iMac from 1998. It’s the same type of processor that NASA already uses in its Curiosity rover.

That’s largely because Mars’ atmosphere offers far less protection from harmful radiation and charged particles than Earth’s atmosphere. A bad burst of radiation can badly wreck the sensitive electronics of a modern processor — and the more complex the chip, the more can go wrong. Plus, at 138 million miles away, it’s not like NASA can just swap out the processor if things go sideways. Because of those conditions, Perseverance actually features two computing modules: one is a backup just in case something goes wrong. (A third copy of the module is also on board for image analysis.)

To make the system even more durable, the PowerPC 750 chip in Perseverance is a little different than the one in the old iMacs. It’s technically a RAD750 chip, a special variant that’s hardened against radiation and costs upwards of $200,000. The chip is popular for spacecraft, too: in addition to Perseverance and Curiosity, it also powers the Fermi Space Telescope, the Lunar Reconnaissance Orbiter, the Deep Impact comet-hunting spacecraft, and the Kepler telescope, among others.

While the processor may be weak compared to a modern smartphone or gaming PC, NASA’s spec sheet for Perseverance notes that it’s far more powerful than earlier rovers like Spirit or Opportunity: its 200MHz clock speed is 10 times faster than those older rovers, and with 2GB of flash memory, it offers eight times the storage. (Rounding things out, Perseverance also has 256MB of RAM in case you were looking to build your own rover.)

 

[Beja]

Sorry, the link above may be paywalled - here's the gist of it.

Hi Andrew, Thanks for the surprising information.. with 200MHz and 256 RAM it looks like Arduino project, but the $200.000 price of
the chip ends the misunderstanding

 

[agraham]

it’s not like NASA can just swap out the processor if things go sideways

Actually, as I understand it they can! . I think there is a redundant identical processor/memory that NASA can switch in if needed.

 

[Beja]

Actually, as I understand it they can! . I think there is a redundant identical processor/memory that NASA can switch in if needed.

? ?
Military design! Don't take chances