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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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Does Venus have a north star or south star?

I am trying to figure out how you would navigate on Venus. On Earth you can use Polaris as a North Star to find north. Would there be a star on the Venus sky which could function as either a north ...
Erik Engheim's user avatar
5 votes
5 answers
706 views

How might Earth's location be referenced in stellar terms?

Apologies if this has been asked before using terminology for somebody more familiar with the subject matter. I've searched but cannot find an answer. Assuming space travel was possible (to other ...
EvilDr's user avatar
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2 answers
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What's a good source of information on determining spacecraft positions via radio?

I'm willing to spend a decent amount on a textbook, but please tell me about cheap or free sources as well.
Schlusstein's user avatar
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5 votes
1 answer
258 views

What determines if a star tracker blends two stars that are close to each other?

If two stars are very close to each other, a star tracker could identify the pair as a single star, with a magnitude and position different from both stars. This obviously impairs the software's ...
Arthur Dent's user avatar
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2 votes
3 answers
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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/...
uhoh's user avatar
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Satellite Position

The Voyager 1 took one last photograph in 1990 and after that, the camera equipment was shut off for power saving. However, the estimates of where the photo was taken in space vary by many hundreds of ...
Takeru Nakajima's user avatar
9 votes
1 answer
529 views

How do we define geographical coordinates on non-spheroid celestial bodies?

On Earth, we can use latitude and longitude to fairly accurately describe a single point on the surface of the earth. This works because the earth is, for all intents and purposes, a sphere. It got me ...
Colin Basnett's user avatar
2 votes
1 answer
290 views

Navigating to Proxima-B

What sorts of unique problems are there with planning a trajectory to Proxima Centauri, besides it being out of the plane of the ecliptic? (I'm guessing if you've got the juice to make it there, ...
PHChilly's user avatar
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2 votes
2 answers
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Height of navigation satellites above Earth

What is the distance between the Earth's surface and the motorists' satnav satellites?
G R Blackburn's user avatar
11 votes
3 answers
486 views

How is the trajectory of spacecraft transferring between planets monitored?

The doppler effect can give a pretty measure of radial speed relative to Earth, and radio transmissions can narrow down the radial position, but what about everything else? I can imagine several ways, ...
Schlusstein's user avatar
  • 2,157
4 votes
1 answer
230 views

What naturally occurring navigational information is available for an autonomous return of SLS's EM-1?

This answer details some of the requirements that would need to be met if the Space Launch System's planned Exploration Mission 1 were to be human rated. I've further trimmed that truncated selection ...
uhoh's user avatar
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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 ...
uhoh's user avatar
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How might the Lunar X Prize contestant spacecraft have navigated their descent from orbit, to landing?

EDIT: Please note the following items: The Mission Requirements for claiming the Grand or Second Place Prize include the following: Landing – A team must land its craft on the surface of the Moon ...
uhoh's user avatar
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18 votes
2 answers
2k views

What was the globe instrument in Vostok 1?

This image was attached to the Wikipedia article on Vostok 1 with a perfunctory caption "Part of the Vostok 1 instrument panel". I'm interested in the globe in the center. What is the name of this ...
SF.'s user avatar
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5 votes
4 answers
674 views

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 ...
uhoh's user avatar
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4 votes
2 answers
607 views

How would you navigate an airship on Venus?

Since there is no magnetic field compass is out. No GPS satellites either. I guess some old school methods could be used but I see some potential problems. Assume we are over the cloud tops, can we ...
Erik Engheim's user avatar
10 votes
1 answer
594 views

Does NASA use Newtonian model of gravity for plotting the course of Juno or general relativity?

With the huge mass of Jupiter and its fast, approximately 10 hours daily rotation, there may be substantial twisting of space-time around it. A distortion of such magnitude that may call for ...
kamran's user avatar
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5 votes
1 answer
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Deep space craft antenna aiming

In order to aim an antenna at Earth, how do unmanned spacecraft find their own orientation (xyz position in space, what direction it is flying and which direction the antenna is pointing)? Are they ...
EEd's user avatar
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3 answers
529 views

How would an interstellar probe navigate the pull of gravity from stars and other large objects on the way?

Refer to the ambitious probe sent by Yuri Milner, Stephen Hawking and Mark Zuckerberg to Alpha Centauri: Yuri Milner is spending $100 million on a probe that could travel to Alpha Centauri within ...
Graviton's user avatar
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13 votes
1 answer
862 views

Will Glonass, Galileo, or BeiDou-2 satellites provide better cis-lunar navigation than GPS?

My question is: Has there been any effort to improve or optimize the radiation patterns on the subsequent satellite navigation constellations (e.g. Glonass, Galileo, BeiDou-2) to facilitate trans-GEO ...
uhoh's user avatar
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1 vote
0 answers
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Has GPS been used beyond GEO? [duplicate]

When researching this question I came upon a presentation entitled Enabling a Fully Interoperable GNSS Space Service Volume; slides 12, 24, 25, 26 are also shown below. The idea is that while GPS ...
uhoh's user avatar
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How is space mapped out?

Here on earth, we have four directions(East, West, North, South). We have earth maps which shows our exact location from any other location in 2D plane. But in space, planets and stars are in three ...
Kamalesh Wankhede's user avatar
16 votes
2 answers
5k views

How are GPS satellite clocks synchronized with each other in the earth's frame of reference?

I have been looking at different threads. It seems like the receiver clock on Earth doesn't have to be synchronized with the satellite clocks. But I believe the satellite clocks need to be ...
Ameet Sharma's user avatar
37 votes
1 answer
15k views

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 ...
Chris Nevill's user avatar
3 votes
2 answers
375 views

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 ...
privetDruzia's user avatar
1 vote
4 answers
762 views

Do GPS receivers use trilateration or distances between satellites?

My main question is whether GPS receivers use trilateration or the distances between satellites. On GPS.gov and their videos, it says you receivers use trilateration. But, I have seen people say that ...
Hawkeye's user avatar
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20 votes
3 answers
7k views

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 ...
spk578's user avatar
  • 303
9 votes
1 answer
1k views

Radiation pattern and signal strength of navigation satellite antennas

Where can I find the actual radiation pattern and signal strength of transmitting antennas used by GNSS navigation satellites/constellations (GPS, GLONASS, IRNSS, etc)?
akum's user avatar
  • 328
9 votes
1 answer
1k 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 ...
Matt's user avatar
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12 votes
2 answers
1k views

Will New Horizons seek a third target?

New Horizons will fly past the Kuiper Belt object 2014 MU69 in January 2019. This will use 56 m/s of the remaining ∆V budget of 130 m/s (1). The encounter will occur near the inner edge of the belt: ...
Potatoswatter's user avatar
8 votes
1 answer
631 views

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,...
Kuldeep Barad's user avatar
9 votes
2 answers
1k views

Interplanetary ranging accuracy?

What are the two or three most accurate technologies used to determine interplanetary spacecraft distance (e.g. Doppler / radiometric tracking...), and what accuracy is currently obtained from such ...
mins's user avatar
  • 5,033
2 votes
1 answer
175 views

Where do the poles of the Solar System point? [closed]

The solar system is like a big rotating disk, so it has an axis. Where do the two ends of the axis point in space? To put it another way, where in the sky are the two furthest points from the ...
gostone's user avatar
  • 29
3 votes
1 answer
323 views

How is real position of probes orbiting other planets measured?

I imagine that measuring real positions and orbital elements of satellites orbiting other planets after they perform braking maneuver to get to their final orbit must be rather difficult. Especially ...
Irigi's user avatar
  • 675
6 votes
3 answers
258 views

Does Philae's waking enable scientists to determine its location?

Now that Philae has woken, is more known about its exact location? In other words: does Philae know where Philae is? Navigation on Churi sounds challenging.
gerrit's user avatar
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3 votes
1 answer
440 views

Is this photo of Mars in color?

This recently released terrain of Mars as taken by the Curiosity Rover looks like it was done in black and white. Is this really how it looks like to the naked eye? From here.
Scott's user avatar
  • 749
2 votes
1 answer
128 views

How close can Rosetta come to the 67P/Churyumov-Gerasimenko comet?

ESA publishes quite a few images from the 67P comet, sent by Rosetta, from various distances away to collect as much as possible and as varied as possible. As I write, Rosetta is 6 Km away from the ...
Eric Platon's user avatar
12 votes
4 answers
8k views

Accelerometer in space

If my understanding of the General Theory of Relativity is correct, according to the Equivalence Principle, forces due to gravity and acceleration are indistinguishable. If that's the case, then an ...
Super-intelligent Shade's user avatar
8 votes
1 answer
314 views

Navigation within solar system

I know star trackers are used in most cases for attitude determination of space craft traveling within the solar system. But what methods are currently used for coordinate determination, i.e. the ...
Super-intelligent Shade's user avatar
9 votes
2 answers
278 views

Could a swarm of probes autonomously establish orbit around an asteroid?

To position a spacecraft around an asteroid, one must know the orbital parameters and orientation of the asteroid and the spacecraft. Formation flying will be more complex in terms of positioning ...
akum's user avatar
  • 328
16 votes
4 answers
6k views

How does GPS work exactly?

For a GPS receiver to estimate its position, it first receives signals from at least 4 satellites. Does the receiver calculate the distance that separates it from each satellite, or does it just ...
Noureddine's user avatar
1 vote
1 answer
68 views

Diurnal Signature of Earth in Angular state tracking

'Diurnal signature of the earth related to the the rotation of the earth is utilized and 24 hours of amplitude and phase data is used along with Ranging and Doppler shift data to calculate Angular ...
Kuldeep Barad's user avatar
15 votes
1 answer
1k views

How do probes locate themselves?

There's no way for any probe that is sent to orbit/land on a distant body to get there only on precalculated flight parameters alone - minuscule errors in the beginning of flight would convert to huge ...
SF.'s user avatar
  • 55.1k
19 votes
5 answers
1k views

What is the deepest position in space we can get a GPS signal? [duplicate]

Can we use GPS in orbit at the moon? What about on Mars?
Kamic's user avatar
  • 293
15 votes
2 answers
2k views

Can the satellites in Martian orbit be put to use providing a rudimentary GPS system on Mars?

This website conveys the impression a rover on the Martian surface necessarily navigates by dead-reckoning. Stereo images are used to determine how far a rover has travelled; an advancement over older ...
Everyone's user avatar
  • 13.6k
6 votes
3 answers
912 views

What algorithms are used to correct the flight-path?

As a launch vehicle begins to veer slightly off course during a launch, what sort of algorithms are used to determine how far off the vehicle's trajectory is pointing from the intended trajectory and ...
Stu's user avatar
  • 5,938
7 votes
1 answer
785 views

What conventional reference frame is used for interplanetary telemetry and navigation?

Specifically a location in the celestial sphere that is fixed, most likely a star, which creates a set of still coordinates with respect to the Sun. There are many ways to do this, but I am interested ...
Stu's user avatar
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13 votes
2 answers
9k views

How does a rocket navigate during launch?

From what I understand, a rocket changes its direction during launch by gimbaling its engines (i.e. swiveling the engine nozzles so the thrust of the engine points in the correct direction). But what ...
Bill's user avatar
  • 809
6 votes
2 answers
857 views

How are artificial satellites of non-Earth celestial bodies positioned?

A body on Earth's surface can be positioned easily knowing the GPS coordinates, assuming the body is in direct path or 4 GPS satellites. But how is a satellite (say Maven or India's Mangalyaan) which ...
x0x's user avatar
  • 163
7 votes
1 answer
346 views

How quickly could a craft find its location using only pulsars?

I'm only just beginning to scratch the surface of the possibilities in interstellar travel. I know that pulsars can be independently identified by means of measuring their pulses, and that once enough ...
Kromey's user avatar
  • 331