Questions tagged [navigation]

Topics that relate to orbit determination and flight path control. May also be used for navigation on the surface of celestial objects.

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Finding way back in Intergalactic travel

Is it possible to create GPS-equivalent system for space travel to guide us in which direction to travel? Assume that if we are able to reach a far-off galaxy millions or billions of light-years away ...
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What's the current state of Mars orbital infrastructure?

As per this Wikipedia article Mars currently has 6 operational artificial satellites: 2001 Mars Odyssey Mars Express Mars Reconnaissance Orbiter Mars Orbiter Mission Mars Atmosphere and Volatile ...
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What's the current state of Venus orbital infrastructure?

As per this Wikipedia article there have been a total of 5 orbiters successfully deployed to Venus: Venera-15 Venera-16 Magellan Venus Express Akatsuki Of which only the Akatsuki seems to be ...
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Given small computational resources, how was navigation implemented? (Not samples of old guidance software)

Update 2 : The youtube vidoe How did NASA Steer the Saturn V answers this question and then some, a must watch. Update: I really wanted to know how spacecraft navigation (not guidance) computers ...
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How can a deep-space spacecraft determine in real time the direction of delta-v?

My spacecraft knows it wants to add a certain delta-v in a certain direction to its motion, relative to the stars. It will calculate current mass based on propellant usage history, which hasn't been ...
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Travel time from lunar orbit (EML2) to Jupiter using skyhook only?

I am doing background research for a science fiction story, and hoping someone can help with this navigational question. Voyager 2 reached Jupiter from Earth in about 2 years. However (if I understand ...
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Mode during Apollo landing in cross pointer

In this Question the excellent answer explains from the handbook that the cross pointer input can be either from landing radar or PGNS or AGS. My question is which mode was choosen during the final ...
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How did astronauts navigate the Lunar Roving Vehicle (LRV) over the surface of the Moon?

The Lunar Roving Vechicle (LRV), also known as Moon Buggy, was used as a form of transportation on the surface of the Moon during the Apollo program. What system did the astronauts use for ...
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Is pulsar timing a viable positioning system for solar system missions

I was reading one of the questions about a version of GPS around Mars, and I started wondering about a Solar system wide positioning system -- large satellites with accurate clocks and powerful ...
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Soyuz has a Space Periscope?

The image Photo ID: ISS049-E-003166 can be found in Flikr and Wikimedia Commons as well as in Spaceflight Now. There is a long (perhaps 1 meter?) green structure that is sticking out from the side of ...
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Perseverance Rover to drive carefully for months while helicopter hangs from underside?

The image below is cropped from the high resolution version of NASA's Mars Helicopter and Perseverance Rover PIA23824 and shows the helicopter in it's stowed position on the underside of the rover ...
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How can I generate Chebyshev cofficients from SPICE for J2000 Inertial to Moon ME Frame?

I want to extract the Chebyshev coefficients in order to be able to calculate the time-varying transformation from the ICRF / J2000 Inertial frame to the Moon ME (moon mean earth) frame. I know I can ...
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Can we go anywhere in space with only THREE reaction wheels and ONE chemical thruster?

I had a discussion the other day with some of my peers and they were very keen on the fact the it is possible to change your orbit as desired using a single thruster and a three reaction wheels. The ...
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How could you turn a satellite constellation into a SatNav system?

Apparently, the UK government wants to convert the OneWeb satellites into its own UK SatNav system, following Brexit which limits the UK's access to Galileo's Public Regulated Service [reports from ...
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Navigating in space with only cameras

I'd like to figure out how to determine where something is in space (solar system) based only solely on measurements that can be preformed on location visually/with a camera. Let's say I'm floating in ...
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How did early inertial navigation systems handle vibration?

In the early ICBM-era rockets, it seems that inertial navigation accuracy was critical. How did these systems filter out the noise in the data due to the vibration of the rocket? If a fairly slow ...
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Is there any kind of research on *sub*-orbital rendezvous-ing with a space tug outside the atmosphere?

The key difference with a plain old-fashioned orbital rendezvous would seem to be that there'd be limited time to only briefly match velocities and trajectories: Let's say a vehicle launched from ...
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How does Falcon 9 differ from Shuttle or Apollo inertial guidance?

I read a very detailed analysis of the Saturn V. From it I learned there is a computer and guidance "room" which is an extra slice of rocket stacked between the 2nd or 3rd launch stages and the the ...
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Autonomous Navigation for deep space missions

Autonomous navigation started in early phases of deep space exploration as a provision to achieve accuracy for planet/natural satellite targeting and approach, where radio tracking accuracies were low,...
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What is the math behind satellite star trackers?

I'm trying to understand how star trackers on satellites work and what math they use to determine attitude. For example, is there any trigonometry involved with the stars and how specifically does ...
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How does a space vehicle which carries Curiosity or Spirit rover reach a planet? [closed]

I don't know much science but was curious about it. So, what I've seen in movies is that there are lot of objects in the space and many other space items (made of rocks, moving stars etc.). So when ...
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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 ...
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What is the nature of the sextant tests on the ISS for Orion cis-lunar emergency navigation?

According to the NASA Johnson video Space to Ground: A Star to Steer By: 08/10/2018: A tool that once helped sailors cross vast oceans for centuries is now being put to the test in space. The crew ...
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How to estimate that receiving GNSS signals Earth while orbiting the Moon will still provide locations to about 200 meters of uncertainty?

IEEE Spectrum's Can Astronauts Use GPS to Navigate on the Moon? NASA Scientists Say Yes says: Kar-Ming Cheung and Charles Lee of NASA’s Jet Propulsion Laboratory in California did the math, and ...
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Is there any open source software that can compute GPS ground coverage? I need a free alternative to AGI's System Tool Kit (STK)

Does any open source software exist that can compute GPS ground coverage in real time? At work I used STK which would do the job perfectly, but I'm at school now so I only have the free version. For ...
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How will NASA's software for autonomous navigation in cis-lunar space work?

NASA news item NASA Funds CubeSat Pathfinder Mission to Unique Lunar Orbit says: The pathfinder mission represents a rapid lunar flight demonstration and could launch as early as December 2020. ...
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What is the deepest position in space we can get a GPS signal?

Can we use GPS in orbit at the moon? What about on Mars?
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Could Apollo astronauts see other planets with the CM Scanning Telescope?

The Apollo Command Module had the Scanning Telescope for navigating, "Apollo astronaut located a specific star using a single-power, wide-field telescope." I'm not concerned whether it could ...
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How would blockchain be integrated into spaceflight? Have any methods been proposed yet?

Blockchain offers a way of keeping track of information such that its authenticity can be verified and it can not easily be falsified. In a space environment with an increasing number of both active ...
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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 ...
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What is the precision attitude estimation strategy for satellites, under impulsive thrust manoeuvres?

Satellites mostly rely on star trackers and gyros for precision attitude knowledge. Under impulsive thrust manoeuvres, I expect the star trackers to blur and provide no attitude knowledge. What is the ...
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Can reaction wheels be used for detumbling?

During orbit insertion, the satellite can start with a high tip-off rate which requires detumbling. From what I have read, detumbling is usually done using magnetorquers. I was wondering if ...
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Azimuth and elevation from satellite point of view [duplicate]

I have read for calculating azimuth and elevation from the Earth we use north east up reference frame. What reference frame is used for satellite to measure azimuth and elevation on the Earth? And ...
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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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How did the star tracker on the Corona (Key Hole) satellite work?

The first Corona Photographic Surveillance Satellite was launched in 1959. Starting from the third mission, launched in 1961, the satellites were equipped with a star tracker. From Wikipedia: ...
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Radar Altimeter in Space Shuttle

I was going throught the Space Shuttle Handbook, chapter Guidance and Navigation. In one of the Note boxes, it is written Radar altimeter altitude is not used for navigation or guidance. The ...
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Have lunar (or martian) rovers exploited shadows, perhaps for terrain comprehension or obstacle avoidance?

This answer proposes that light bars would be better than a single headlight for night time navigation on the Moon because a single headlight will generate hard shadows. Considering this is exactly ...
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Is there a Martian “North Star”, usable as Earth's North Star?

Mars has a different axial tilt than Earth. It stands to reason that the constellations will remain identical from Mars, but their locations will be somewhat different. On Earth, the North Star is ...
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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"). ...
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What exactly is rhumb-line control in the context of a launch trajectory?

The conference paper SS-520 Nano satellite launcher and its flight result SSC18-IX-03 from the 32nd Annual AIAA/USU Conference on Small Satellites linked in this answer describes the use of rhumb-line ...
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How did the Apollo 11's Eagle ascent stage find the CSM after leaving the Moon?

I've always been curious how did the Apollo 11's Eagle ascent stage of the Apollo Lunar Module navigate back to the Apollo Command/Service Module (CSM) that was in lunar orbit? Was it simply a case ...
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How did astronauts using rovers tell direction without compasses on the Moon? [duplicate]

I read that the astronauts who used Lunar rovers used heading indicators, which typically use compasses, for direction. How, on the Moon, did their equipment tell the direction of travel, presuming a ...
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Help understanding exactly how an atomic clock facilitates “self-driving spacecraft” when paired with an onboard camera?

The TechCrunch article NASA details Deep Space Atomic Clock and other tests launching on SpaceX Falcon Heavy says: Jill Seubert, Deep Space Navigator for NASA, explained that this is the world’s ...
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How does an onboard atomic clock help interplanetary navigation?

On 2019 June 22, JPL will launch and test the accuracy of an onboard atomic clock. Its FAQ says that it will improve interplanetary navigation because for the ship to determine its position, instead ...
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What is a gyrocompass and how might one be used by a planetary rover?

In comments and links therein below the question How does Curiosity know how to point and move it's high gain antenna in real time? there is mention of a gyrocompass. I am aware that gyros can be ...
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Satellite mission design/performance requirements to attitude/orbit control design specifications

Are there any good sources that discuss: the steps involved in deriving attitude/orbit control design specifications, from satellite mission design/performance requirements?
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When was stereoscopic photography first used intentionally on solar system body?

I have stumbled across the fascinating page Photogrammetric Analysis Of Apollo 11 Imagery: New camera-station map with improved locations at the following website: https://www.hq.nasa.gov/alsj/a11/...
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Does the “17” really mean anything with respect to GNSS orbits being rational factions of a sidereal day?

This answer suggests that the orbital periods of the four large GNSSS contstellations are linked to the sidereal rotation period of the earth by rational numbers with 17 or 34 as the denominator in ...
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State of the art of satellite Attitude Determination and Control Systems

I know I might get an answer like "the sky is not the limit"... But considering the actual state of the art of modern satellites ADC systems. Haven't we reached a "maximum" yet? Or are there still a ...
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Have guidelines for red & green navigation light placement on spacecraft been established?

update: Cropped screen capture from SpaceX Demo-1 Crew Dragon Docking to ISS - Part 2 after about 00:25:00 in the video: I am curious if guidelines for the ...