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.
178 questions
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Can anyone share or provide a source for these 1970s Project Apollo documents
doc title: Manually-aided on-board Apollo cislunar navigation Document ID: 19710029813 Publisher: INST. OF NAVIGATION, pub date: January 1, 1970 NTRS Distribution Limits Public Link to NTRS "...
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24votes
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Does the Moon really need its own atomic clocks and timescales, separate from those used on and around Earth?
Recently there was a flurry of "The Moon needs it's own atomic clocks" popular news items (see a sampling, below). The premise is that since "time works differently there" and ...
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3votes
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GPS/GNSS at cis-lunar and the Moon; what exactly did LuGRE do, and how did it do it?
LuGRE, or Lunar GNSS Receiver Experiment is a payload on Blue Ghost Mission 1 (2025-010A, 62716) and in early March it made a lot of news by receiving and processing GNSS signals from GPS and Galileo ...
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Will New Horizons overtake Pioneer 10 and Pioneer 11 in distance from the Sun? If, so when will this happen?
Will New Horizons ever overtake Pioneer 10 and Pioneer 11 in distance from the Sun? If, so when will this happen?
12votes
0answers
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How accurately could we aim a cubesat at Alpha Centauri?
Let's assume the 1U cubesat sized object is a solid block of convenient material, convenient shape and color, with no propulsion, no communication. It's sent chemically and meant to reach Alpha ...
4votes
0answers
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What books, papers, or other references discuss spacecraft GNC software architecture?
I am seeking reference material not necessarily on the principles of GNC itself (I already own most popular books on it), but on the actual software architecture for onboard GNC. I am having trouble ...
17votes
4answers
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How would a spacecraft figure out its own orbit, without help from earth?
I was looking into this as a tangent while reading about Orbital Determination, but I can't seem to find any literature on the subject. I am trying to make my own solution but can't quite seem to ...
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Why does the Global Positioning System include particular numbers of satellites?
The Global Positioning System (GPS) includes at least 24 satellites operating approximately 20,200 kilometers above the earth and distributed in six orbits. Why 24 satellites, six orbits, and 20,200 ...
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5votes
1answer
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Does XNAV (Pulsar navigation) give an absolute position, or a position in relation to the arbitrary inertial reference the system initiates with?
With Pulsar-based navigation (XNAV) https://en.wikipedia.org/wiki/Pulsar-based_navigation , X-ray pulsar signals from a multiplicity of pulsars are used to determine the position of a spacecraft. It ...
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Inter-constellation Low Earth Orbit (LEO) Satellite collision risks - mitigation is some "relayed AIS" in use?
I saw some news about Starlink satellites often having the do maneuvers to avoid collisions. I don't know what % of the maneuvers were related to collisions between 2 Starlink ones (I guess their ...
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How can GPS provide a spacecraft's attitude? [duplicate]
According to https://en.wikipedia.org/wiki/Statevector Orbital state vectors are vectors of position and velocity that, together with their time, uniquely determine the state of an orbiting body in ...
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How does a Space-Stabilized Inertial Navigation System actually torque its gimbals?
I've been trying to make a fairly-accurate video (with 3D animations coming soon) about Inertial Navigation Systems (INS), in which I plan to cover all the details from each gyroscopes and ...
3votes
0answers
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What online courses teach you hands on AOCS GNC?
I am looking for online courses that teach you "attitude and orbit determination and control systems" and "guidance navigation and control" with a focus on satellites or space ...
2votes
1answer
97views
Satellite Navigation: Measuring Velocity & Position
How is the position and velocity of a satellite measured from ground? Radar measurements could give us range and range rate which are scalar quantities (if I understand this correctly). But how could ...
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4votes
1answer
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What are the likely issues and challenges in developing LTC: Coordinated Lunar Time?
In April of 2024, the US White House directed NASA to define a workable definition and operational plan for LTC: Coordinated Lunar Time. White House directs NASA to create time standard for the moon | ...
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