Questions tagged [flight-computer]

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

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130
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2answers
19k 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. ...
101
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6answers
20k 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 ...
32
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2answers
41k 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 ...
24
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2answers
7k 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 ...
24
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4answers
6k views

Is the Pi really fit for outer space?

Recently, there has been growing interest in using Raspberry Pis in CubeSats. NASA is even in on the trend. But, considering that outer space is pretty harsh on electronics (i.e. radiation and cosmic ...
23
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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 ...
23
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3answers
2k views

How often are ISS computers (MDMs) replaced?

The electronic "heart" of the International Space Station are the Multiplexers-Demultiplexers (MDMs) located within & outside the pressurized modules. How often are they replaced? (An ideal ...
23
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1answer
5k views

On-board computer / data handling system of Rosetta - details?

I seek detailed information on the computer and/or data handling system of Rosetta. Who manufactured it? What type(s) of CPU is used? What kind of architecture does it belong to and at what ...
23
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1answer
1k views

How are flight plans calculated?

When a project like Rosetta is being developed, how are flight plans calculated? Do planners simply input the desired target into a program or a flight computer which spits out the optimum flight path ...
22
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9answers
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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 ...
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 ...
21
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2answers
3k 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 ...
20
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1answer
5k views

Why is a stick required to operate Soyuz's computer?

In this screenshot from the recent Soyuz TMA-12M launch, a crewmember is seen using a stick to enter commands into the computer: Is this stick standard, taken on all Soyuz flights? Also, why aren't ...
18
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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. ...
17
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1answer
3k views

If the space shuttle computers all output contradictory commands, how is it chosen?

The space shuttle computers use triple-redundancy, and if one computer contradicted the other two, it would be ignored. I read that if all three gave contradictory output, one computer would be ...
17
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1answer
2k views

What space applications, projects and agencies are using the Ada programming language?

The answer to this question mentions the use of Ada-programmed applications on the ISS. Ada was developed for the US DoD to replace a plethora of computer languages (some 465), for mission-critical ...
16
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1answer
6k views

Operating system of New Horizons spacecraft

I've been doing some searching and I can find some technical details about the flight computer of the New Horizons spacecraft. What I've found is: It has a Mongoose-V 32-bit CPU (a radiation hardened ...
15
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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 - ...
14
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2answers
9k views

Which operating systems is the International Space Station running?

I've seen some of the articles mention that ISS switched from Windows to Linux. But that's just considering the laptops. What OS are the other computers present on ISS running? I would think that e.g. ...
13
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1answer
2k 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 ...
13
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4answers
2k views

Do any systems in space use Artificial Intelligence yet?

Technology has apparently advanced to the point some states in the Untied States are debating AI managed cars. The thought comes to mind that space is relatively less crowded than most streets on ...
13
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1answer
4k views

Why did the ESA choose SPARC for LEON?

In late 1997, the European Space Agency started the LEON project to provide higher performance processors for ESA missions. An open instruction set architecture was a first-level requirement (both to ...
12
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3answers
749 views

RTOS vs Linux against single event upsets

I am working on the on-board computer for a CubeSat. Our computer will be vulnerable to radiation, hence single event upsets, e.g. bit flips are likely to occur. Would a lighter, smaller OS like ...
12
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2answers
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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 ...
12
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1answer
660 views

Are all crew on board a spacecraft trained to handle flight-systems?

Spaceflightnow.com writes to say (Edited to apply my highlights) "The improvements are rather significant," Kelly said in a NASA interview. "The displays that the cosmonauts and myself ... use to ...
11
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4answers
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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 ...
10
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3answers
635 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 ...
10
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1answer
1k 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 ...
10
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1answer
550 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 ...
10
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1answer
214 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 ...
10
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1answer
233 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-...
9
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1answer
1k views

Using non-radiation-hardened processors in lunar orbit …

Is it feasible to design a flight computer for a small CubeSat spacecraft destined for lunar orbit that is controlled exclusively by one or more non-radiation-hardened processors? What are the main ...
9
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1answer
342 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 ...
8
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1answer
779 views

What is the maximum acceptable latency in rocket control computers?

Rockets require real-time computers, in that there are operational deadlines between events and system response. How quickly does the rocket's controller need to respond to sensors and events, without ...
7
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2answers
941 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/...
6
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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?
6
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3answers
240 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 ...
6
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1answer
199 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 ...
6
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1answer
329 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 ...
6
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1answer
266 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....
6
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0answers
224 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 ...
5
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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-...
5
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1answer
119 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 "...
4
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1answer
398 views

Why aren't there more guidance computers on cargo rated launch vehicles?

According to this video human-rated launch vehicles can have six guidance computers while cargo-rated launch vehicles seldom have more than two. If these computers function independently for greater ...
4
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2answers
168 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 ...
4
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1answer
919 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'...
4
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2answers
1k views

What are the MDM's on the ISS, and how many different kinds are there?

In the prelude for SpaceX CRS-3 mission, the failure of a Multiplexer-Demultiplexer (MDM) on the International Space Station (ISS) seems to be a real concern for launching. In the pre-launch press ...
4
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1answer
137 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 ...
4
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1answer
372 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 ...
3
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2answers
293 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:...