Questions tagged [flight-computer]

Questions regarding the computers onboard spacecraft which handle mission-critical data.

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Computer Systems onboard Europa Clipper

Is known which Computers Europa Clipper will be using? I'm guessing it will be RAD750 again, but I couldn't find any official sources. Thanks for the help
RAD6000's user avatar
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10 votes
5 answers
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Electronic Circuits for Safe Initiation of Pyrotechnics?

Pyrotechnic charges are initiated using e.g. the NASA Standard Detonator or the NASA Standard Initiator. I don't know the exact specs, but I assume that these will be driven with a few amps in the kV ...
latlon's user avatar
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Why does Interstellar Probe need 2 TB of memory

This article says that Interstellar Probe is supposed to have two terabytes of memory(which I assume means storage, not RAM). What does it need so much for? New Horizons had 8 gigabytes of storage, ...
G12's user avatar
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2 votes
0 answers
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Are there already spacecraft equipped with RAD5500 processors?

Just stumbled across RAD750s successor, the RAD5500. Are there already spacecraft using this Chip, or are there plans for this chip? Looks pretty new!
RAD6000's user avatar
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4 votes
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What kind of hardware and software does the James Webb space telescope computer use?

What kind of software, operating system, database, processor, architecture, antenna used for communication back to Earth, basically what computer does it use.
Kalai Selvan's user avatar
28 votes
2 answers
7k views

Are the computers on Pioneer 10 & 11 still running?

So, I have been wondering. Pioneer 10 and 11 went silent because there wasn't enough power left to operate the antenna. But what happened after that? Was there still enough power to keep the computers ...
RAD6000's user avatar
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3 votes
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How will InSight's hardware be damaged if the heaters fail?

InSight is scheduled to "die" due to the Dust on the solar arrays. From what I understand, once the power goes out, there won't be a way to keep the computers and batteries warm at night, so ...
RAD6000's user avatar
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Mariner 9 computing equipment

I am guessing the word CPU can't be used in reference to computers in 1971. So I am wondering what type of electronic equipment were put in place of a regular CPU ...
malat's user avatar
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3 votes
0 answers
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What programming language will the lunar gateway run on? How much of its code will be inherited from existing ISS components?

What programming language will be used for the main elements of the lunar gateway? Will programmatical components be inherited from the ISS? If so, to what extent?
Speedphoenix's user avatar
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9 votes
2 answers
1k views

How were registers in the Apollo Guidance Computer implemented?

I'm having a hard time finding information on the composition of the AGC's registers. Were they also Magnetic Core Memory or something else?
Charles Averill's user avatar
0 votes
1 answer
364 views

What would have happened if all Apollo computers failed?

Let's assume all available computers in the command module and the lunar module failed and the astronauts were unable to repair them in flight. Would they have been able to return back home safely ...
Bartosz Brożek's user avatar
24 votes
7 answers
7k views

Why do spacecraft have small RAM? Which spacecraft had the largest memory?

Computers on spacecraft often have small memory, like a few MB. Wouldn't it be nice to put more memory into them? Or is MB-level already enough? Also, which spacecraft has the largest memory?
Zharki voronin's user avatar
29 votes
2 answers
4k views

How did the Apollo guidance computers deal with radiation?

I was wondering how the Apollo guidance computer handled the radiation encountered in space
Devin's user avatar
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13 votes
2 answers
2k views

Did the Curiosity and Perseverance rover brains do the driving from Earth to Mars?

This interesting answer to Why did NASA intentionally crash-land the Curiosity and Perseverance sky cranes on Mars? leads me to wonder if the Curiosity and Perseverance rover computers were in charge ...
uhoh's user avatar
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8 votes
1 answer
189 views

Rad-Hard vs Space-Hard computing

Radiation hardened CPUs like RAD750 are radiation hardened for up to 1000 gray. Cool. But, as CPUs have advanced way ahead their mechanical counterparts in miniaturization and fragility, energy ...
chubakueno's user avatar
2 votes
2 answers
122 views

Efficiency in Space Capsule Docking Process

I'm watching the first operational Crew Dragon Capsule proceed through the regimented, and VERY careful International Space Station (ISS) docking process, which was turned on after pausing another ...
BigNutz's user avatar
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1 vote
2 answers
133 views

Magnetometer in space

See, i recently buy a magnetometer to experiment with arduino, i want start building a litle fly computer for a cubesat (this cubesat have an ion engine, so, have thrust). I start reading the Azimuth ...
Valentino Zaffrani's user avatar
14 votes
1 answer
2k views

How did the Apollo Lunar Rover navigation system computer work?

Unlike the more famous Apollo Guidance Computer I can't find any information about the computer used in the manned lunar rover. It seemed to track three values and display them on analog gauges: the ...
David's user avatar
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23 votes
7 answers
6k views

Unix Epoch in International Space Station

The International Space Station is in a different gravitational field than us on the Earth's surface. Almost all computers / protocols depend on the Unix epoch being consistent everywhere. The Unix ...
exifguy's user avatar
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26 votes
9 answers
10k views

Why would such a powerful computer (or a computer at all) be needed to go to the Moon?

I keep hearing people say things like: Duuuude! It's so insane that we're carrying around phones in our pockets that are a thousand times faster than the computers that took us to the moon! Why do ...
Branko Kieran's user avatar
1 vote
1 answer
248 views

When and when not to use the SDLS protocol?

When should the features provided by the Space Data Link Security Protocol (SDLS) be applied to TM Data Space Link Protocol communications? This is with respect of ensuring protection within the ...
Ieshaan Saxena's user avatar
8 votes
1 answer
4k views

Which operating system is Perseverance running?

A few days ago, I watched Perseverance being launched towards Mars. I know that there is lots of very specific hardware embedded into the rover, so, very likely, there has been software written by ...
publicdomain's user avatar
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8 votes
1 answer
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What is a "flight string"?

This answer explains what software powers the Falcon 9 launch vehicle. The flight software is written in C/C++ and runs in the x86 environment. For each calculation/decision, the "flight string&...
hongsy's user avatar
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-2 votes
4 answers
279 views

Computers for Apollo Mission

Why did NASA invest so much amount of time and money on developing computers for Apollo Missions? Wouldn't the Man on Moon mission have been far easier and faster if the Astronauts drove the ...
Niranjan's user avatar
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7 votes
0 answers
71 views

How long do we have contact with a centaur after launch

When centaur separates the payload, we can see a video signal of this happening. The mission of centaur is completed now, but are there still some activities centaur is performing after seperation? ...
RAD6000's user avatar
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4 votes
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How did the automatic sextant on the late-1950's MIT Mars Probe work?

The reason MIT was chosen to develop the Apollo guidance computer was their Instrumentation Lab. They specialised in inertial navigation and had done impressive work on inertial navigation for ...
Ludo's user avatar
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8 votes
2 answers
293 views

How are Spacecraft Event Times (SETs) managed; to what timescales are they linked?

Spacecraft Event Time explains the importance of remembering just how darn slow light is; it takes minutes, hours, and in a few cases almost a day for light to travel one way between humans and their ...
uhoh's user avatar
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1 answer
354 views

RCS or Reaction Wheel for a 30kg cubesat

I am working on the design of a cubesat, it weighs approximately 30 kg and I am doing the Navigation and Guide Control system. I was wondering if I had some blueprint for some RCS or Reaction Wheels ...
Valentino Zaffrani's user avatar
5 votes
1 answer
147 views

Would astronauts have been able to save the CST-100 mission?

The Boeing CST-100 Starliner failed an unmanned test because the timer on the spacecraft was off by 11 hours. This caused the spacecraft computer to think it was ahead in mission timing by 11 hours, ...
GdD's user avatar
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3 votes
2 answers
607 views

Interplanetary spacecraft flight operating system and programming language

Which programming languages and operating systems are mostly used for interplanetary satellites (such as a mission to the moon)? To my knowledge, I know some LEO CubeSats use C programming language ...
John's user avatar
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10 votes
1 answer
998 views

How would the state vector be updated in the Apollo Guidance Computer during coasting to/from the moon if communication with Earth was lost entirely?

This source https://www.hq.nasa.gov/alsj/alsj-average_g.html states that: From time to time, Houston could update the onboard SV using tracking and other available date; [sic] but, generally, it ...
Sergiy Lenzion's user avatar
1 vote
0 answers
323 views

Commercial 3DoF/6DoF trajectory simulation and optimization tool for launch vehicle

Is there any 3DoF/6DoF trajectory simulation and optimization tool for launch vehicles like POST available commercially? If there whether it's how reliable when it comes to using for real-time ...
Astrolien's user avatar
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48 votes
3 answers
13k views

Why don't we shield existing CPUs from radiation instead of designing new ones?

I've just read this article about space-graded CPUs [1]. I am not a space expert at all but a question was born naturally: why don't we prefer to shield earth-designed CPUs (far less expensive) than ...
mattia.b89's user avatar
-2 votes
4 answers
265 views

What exactly makes PHP CLI fundamentally unsuitable to power all the math on board a space craft?

Let's say that there is an eccentric multi-trillionare who made his fortune by coding a very popular service in PHP. He knows it very well, and has such a love for it that he makes a rather unorthodox ...
SpacedOut's user avatar
12 votes
1 answer
3k views

Double redundancy for the Saturn V LVDC computer memory, how were disagreements resolved?

In the Smarter Every Day video How did NASA Steer the Saturn V?- Smarter Every Day 223 Destin is talking with Luke Talley about the memory modules used in the Saturn V LVDC computer. This computer ...
uhoh's user avatar
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4 votes
1 answer
242 views

How do small, spin stabilized launchers follow a rhumb line?

This concise answer to What exactly is rhumb-line control in the context of a launch trajectory? explains the concept in the context of the SS-520 nanosatellite launch vehicle (which "doesn't exist"). ...
uhoh's user avatar
  • 149k
6 votes
1 answer
378 views

Why did a phase mismatch between the Apollo 11 LM's RR and AGC generate a large numbers of interrupts?

A critical aspect of the cause of the famous 1202 and 1201 alarms reported by the Apollo Guidance Computer (AGC) during the decent of the Apollo 11 LM is that the rendezvous radar (RR) was using a "...
orome's user avatar
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13 votes
2 answers
4k views

Did the 1202 error and associated reboot prevent disaster on Apollo 11 landing?

Most accounts of the famous 1202 error reported by the AGC during landing of the Apollo 11 LM characterize the event as result of the successful operation of the AGC, flushing an resetting an ...
orome's user avatar
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11 votes
1 answer
2k views

Is this really the Saturn V computer only, or are there other systems here as well?

The BBC News article Apollo in 50 Numbers; The Technology shows an image of the Saturn V's computer along with the caption: The Saturn V's computer was probably the largest computer ever blasted ...
uhoh's user avatar
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117 votes
6 answers
26k views

What makes (or at least made) Ada the language of choice for the ISS's safety-critical systems?

We have it on good authority that Ada is widely used for "safety critical software" on at least the US side of the International Space Station. Of all the possible languages to choose from, ...
uhoh's user avatar
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4 votes
2 answers
365 views

What would cause the Shuttle's redundant computers to disagree?

The Shuttle had five AP-101 general purpose computers. As discussed in this question, the system was redundant and there was a voting process to eliminate a computer whose results disagreed with the ...
DrSheldon's user avatar
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9 votes
1 answer
300 views

How did Shuttle computers internally represent time?

How was time represented in the five AP-101 general-purpose computers of the Space Shuttle? How many bits? Encoded as a plain binary count? Split into hours, minutes, seconds, subseconds? Binary-...
DrSheldon's user avatar
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5 votes
1 answer
2k views

Has magnetic core memory been used beyond the Moon?

@aml's comment under @OrganicMarble's answer to the question Did the IBM System/4 Pi computer have radiation-hardened versions for Skylab and Shuttle? says: @uhoh- according to wikipedia, the AP-101B ...
uhoh's user avatar
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5 votes
1 answer
1k views

Did the IBM System/4 Pi computer have radiation-hardened versions for Skylab and Shuttle?

Wikipedia's article on the IBM System/4 Pi says: The IBM System/4 Pi is a family of avionics computers used, in various versions, on the F-15 Eagle fighter, E-3 Sentry, AWACS, Harpoon Missile, NASA's ...
uhoh's user avatar
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23 votes
2 answers
4k views

How did the Apollo guidance computer handle parity bit errors?

The following answers mention the use of parity bits in the Apollo guidance computer: this answer to Bits per core for the different versions of the Apollo guidance computer core rope memory? this ...
uhoh's user avatar
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4 votes
1 answer
202 views

How many AGC keystrokes did an Apollo rendezvous take?

My kids have a rather nice picture book about the first moon landing titled “One Giant Leap”. I find it to be a fairly accurate retelling of the events of Apollo 11 in a poetic style. However, one ...
kgutwin's user avatar
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22 votes
1 answer
5k views

What exactly turned on the light indicating Apollo 8 was starting to fall towards the Moon?

@PearsonArtPhoto's answer links to the page Apollo 8, 21 – 28 December 1968 by Hamish Lindsay at honeysucklecreek.net from where I have quoted below. Question: What exactly turned on the light ...
uhoh's user avatar
  • 149k
6 votes
0 answers
347 views

Why do SD cards perform so much better than SSDs in space?

SD cards and SSDs are based on the same technologies, so why the stark differences in performance? Recently, it was reported that after a year in space, half of the SSD drives on the HPE Spaceborne ...
TeslaK20's user avatar
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6 votes
3 answers
635 views

What are some notable computer systems used in space probes?

I was reading about Cassini and learned that it used a CPU architecture I'd never heard of before, called MIL-STD-1750A. This got me thinking. What are the most common (or otherwise notable) CPU ...
charliegreen's user avatar
1 vote
0 answers
70 views

Distributed computational power-sharing and orbital supercomputer

I had an interesting conversation last night with a nanosatellite engineer about how much computational power is required in a nanosatellite constellation and if it's necessary. I had an idea or a ...
Ondrej Sarnecký's user avatar