Questions tagged [flight-computer]

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

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7
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0answers
37 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? ...
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2answers
49k views

What computer and software is used by the Falcon 9?

I don't know if this would be public, but what CPU / Microcontrollers are used and what software do they run on the Falcon 9? Do they use an OS or is it just bare metal programming? I found some ...
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What are all the ways that FPGAs are used in the Flying Laptop spacecraft?

In the eoPortal's spacecraft Mission profile for the Flying Laptop, the term FPGA (Field Programmable Gate Array) appears 12 times, including the paragraph below. I'm still having trouble ...
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1answer
99 views

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 ...
10
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1answer
641 views

Timing accuracy of the Apollo Guidance Computer?

The AGC timing reference came from a 2.048 MHz crystal clock. But how accurate was this clock circuit? Note 3 of this schematic: "The value of the follwing components to be determined at unit test" is ...
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1answer
487 views

How does the Apollo LM ascent guidance program P12 actually work?

P12 is the AGC guidance program for normal ascent from the lunar surface to orbit. According to the mission planning documents, after separation and ignition, the ascent stage holds its initial ...
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1answer
58 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 ...
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1answer
84 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 ...
4
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1answer
126 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, ...
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2answers
228 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 ...
10
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1answer
691 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 ...
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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 ...
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3answers
12k 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 ...
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4answers
236 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 ...
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3answers
1k views

How would the International Space Station be maintained unmanned?

Russia's lunch to the ISS failed and the crew may have to leave it unmanned. How would the ISS run without a crew? Could some one else take it over or squat in it? https://www.npr.org/2018/10/11/...
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1answer
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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 ...
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1answer
101 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"). ...
9
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1answer
254 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-...
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1answer
151 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 "...
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2answers
3k views

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

Most accounts of the famous 1202 error reported by the AGS during landing of the Apollo 11 LM characterize the event as result of the successful operation of the AGS, flushing an resetting an ...
10
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1answer
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 ...
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6answers
21k views

What makes 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, what are ...
9
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1answer
370 views

What's the record for the longest time a deep space craft has functioned without a reboot?

The question How is Voyager 1 still operating? and the interesting comparison to the record times that Earthbound servers have run without reboot got me thinking about deep space spacecraft. I'm ...
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2answers
208 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 ...
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2answers
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 ...
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1answer
1k 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-...
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1answer
987 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'...
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1answer
156 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 ...
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2answers
323 views

Apollo-11 AGC core memory has 5 wires per core (rather than 3 or 4) - why?

Apollo-11 AGC core memory has 5 wires per core (rather than 3 or 4) - why? I am referring to this image in Wikipedia: https://en.wikipedia.org/wiki/Apollo_Guidance_Computer#/media/File:...
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2answers
20k views

How did the Apollo computers evaluate transcendental functions like sine, arctangent, log?

Navigation with a sextant or maneuvers using gimbal angles might be two examples of cases where an Apollo computer might need to do trigonometry. Trigonometric functions like sine, arctangent, etc. ...
22
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1answer
4k 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 ...
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240 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 ...
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3answers
306 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 ...
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51 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 ...
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1answer
326 views

How accurate can a satellite's orbit be?

How precise can an artificial satellite be when it comes to following the exact orbit in relation to Earth or hitting the same point above Earth in orbit? Which orbit would be the most stable for this?...
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2answers
206 views

Arcustangent function of the Apollo Computer, atan() or atan2()?

What type of the arcustangent function was used, the one with single argument only or the famous atan2(y, x) or arctan2(y, x) with two arguments x and y? What kind of aproximation was used?
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1answer
250 views

Problems as a result of clock drift that have occurred in space?

I was reading this question about the clock drift on the Apollo missions and am sure that a drift of 1 second / day on some of the longer missions would likely result in a mission failure due to the ...
6
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1answer
316 views

Cypress PSOC chips in a Cubesat

The Cypress PSoC line of microcontrollers, especially the PSOC 4 family are very versatile and capable, and seem a natural for use in cubesats. Unfortunately, at least one experiment: http://www.dtic....
10
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3answers
672 views

How many memory banks does Opportunity have?

Sparked by the comments to this answer, how many memory banks does Opportunity have? I'm specially interested in the flash memory but any other info is also welcome. According to this JPL press ...
4
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1answer
452 views

Raspberry Pis in Space?

I'm aware of the Astro Pi (1, 2, 3, 4) on board the ISS, but have there been any other instances of the RPi in space (Astro or not), for example in cubesats or other spacecraft which contain a ...
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4answers
2k views

Successful Linux-based Cubesat missions?

Has anyone had any experience with successful Linux-based flight computer on Cubesat missions? What Linux hardware was used and what problems did you encounter? I am contracted to write flight/ground ...
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2answers
2k views

How is Voyager 1 still operating?

I watched a documentary on Voyager 1 and 2 last night and wondered "how is the digital equipment on them still operating"? I work in IT, and decided to look up what the longest running servers were - ...
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2answers
8k views

How complex was the math and physics necessary to place Apollo 11 on the moon?

Specifically, I'm interested in how closely the models used to calculate the various burns and course corrections represented reality. Was standard Newtonian mechanics sufficient or were relativistic ...
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1answer
1k views

How were these NASA engineers able to take men to the moon and bring them back with this limited computing capability?

The Apollo Guidance Computer had only 2k RAM and 32kb storage. Also what O.S. did they use, and who made it?
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2answers
3k views

What was the first programming language in space?

Sputnik 1 was the first satellite in space. Did it have a programming language on board or was it purely analog? in 1949 Von Neumann released the language Short Code. Fortran was invented in 1957. ...
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2answers
324 views

Commercial grade single board computers (SBCs)

Suppose a nanosatellite is made with several commercial grade SBCs working together. And we design it so as to give output based on majority voting type of algorithm. I am aware of single event upsets ...
25
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1answer
4k views

Was the Apollo 13 CM guidance computer fully shut down?

I was watching the movie Apollo 13, and one thing struck me as quite odd. According to Wikipedia, [Movie director Ron] Howard went to great lengths to create a technically accurate movie, employing ...
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0answers
128 views

What are the features of microcontrollers used in space? [closed]

What are the most desired features of microcontrollers used in space in on-board computers? Are there some special implementations, special functionality? Are features of some microcontrollers not ...
22
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9answers
8k views

Can you really use Arduino for a small spacecraft?

A group of Russian geeks intends to shoot a small vehicle to the moon, which is supposed to photograph the places of the Apollo landings. This will be the ultimate proof that people actually visited ...
6
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1answer
226 views

Who built Juno's chipsets?

Lockheed Martin was responsible for the construction of Juno. But I was wondering who built the chips Juno uses for its onboard computers, and whether or not they are radiation hardened. I would ...