Skip to main content

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.

Filter by
Sorted by
Tagged with
4 votes
1 answer
994 views

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 ...
Vikas's user avatar
  • 371
4 votes
1 answer
325 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 ...
Ludo's user avatar
  • 14.4k
7 votes
2 answers
726 views

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 ...
uhoh's user avatar
  • 149k
4 votes
1 answer
215 views

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 ...
uhoh's user avatar
  • 149k
4 votes
1 answer
245 views

How will NASA's software for autonomous navigation in cis-lunar space be tested; what information is processed, what outputs evaluated?

note: it's been a year and a half and Capstone is scheduled to be launched soon, so perhaps there is more information available now? NASA news item NASA Funds CubeSat Pathfinder Mission to Unique ...
uhoh's user avatar
  • 149k
3 votes
1 answer
123 views

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 ...
Bob516's user avatar
  • 6,999
1 vote
1 answer
366 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 ...
Valentino Zaffrani's user avatar
1 vote
1 answer
78 views

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 ...
Watch This's user avatar
6 votes
1 answer
433 views

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 ...
John's user avatar
  • 1,377
2 votes
1 answer
704 views

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 ...
John's user avatar
  • 1,377
1 vote
0 answers
41 views

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 ...
kartheek's user avatar
10 votes
1 answer
1k 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 ...
Sergiy Lenzion's user avatar
9 votes
1 answer
384 views

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: ...
Ludo's user avatar
  • 14.4k
2 votes
1 answer
124 views

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 ...
zephyr0110's user avatar
  • 2,901
16 votes
1 answer
2k views

Radar altimeter in a space shuttle

I was going through 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 ...
zephyr0110's user avatar
  • 2,901
40 votes
6 answers
16k views

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 ...
jimjim's user avatar
  • 533
2 votes
1 answer
119 views

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 ...
uhoh's user avatar
  • 149k
4 votes
1 answer
247 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"). ...
uhoh's user avatar
  • 149k
4 votes
1 answer
771 views

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 ...
uhoh's user avatar
  • 149k
23 votes
2 answers
8k views

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 ...
john doe's user avatar
  • 636
4 votes
2 answers
164 views

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 ...
uhoh's user avatar
  • 149k
5 votes
1 answer
302 views

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 ...
Camille Goudeseune's user avatar
2 votes
1 answer
217 views

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?
Watch This's user avatar
2 votes
3 answers
453 views

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 ...
Prototypist's user avatar
4 votes
1 answer
400 views

Celestrak GLONASS TLE's showing satellite numbers not listed in the GLONASS constellation, others missing

For a project, I'm retrieving TLE information live from https://celestrak.org/ and using them to simulate satellite orbits. The TLE's for the GLONASS constellation (https://celestrak.org/NORAD/...
Brian C. Peters's user avatar
12 votes
1 answer
519 views

When did Houston figure out where the Eagle had landed?

Between starting the descent burn three seconds late, and having to avoid landing in a boulder field, the Apollo 11 descent module almost completely missed the target landing ellipse. During Apollo ...
Mark's user avatar
  • 15.3k
7 votes
1 answer
287 views

Spacecraft Navigation

Reading fascinating things about New Horizon's journey in the Kuiper Belt, I asked myself the following question: how can one know the spacecraft's position and speed, and with which precision? Of ...
Antoine Ducros's user avatar
8 votes
2 answers
159 views

A gedanken on being able to navigate back to Earth

Imagine a sphere centered at Earth with a radius of 4 light years. Suppose we pick a random point on the surface of this sphere and drop someone, let us say, "Joe" there. Will Joe be able to come back ...
sku's user avatar
  • 191
1 vote
0 answers
87 views

How can New Horizons reliably approach Ultima Thule over a huge distance? [duplicate]

How did New Horizons navigate to Ultima Thule over 80 million miles from Pluto given the chaotic effect of gravity (from unpredictable local and distant matter) on New Horizons and the fact that the ...
Mark's user avatar
  • 59
5 votes
3 answers
439 views

Why doesn't New Horizons have a tracking function

Dr. John Spencer mentioned in the live feed for the Ultima Thule flyby they're taking a series of LORRI shots along a precomputed path hoping to capture the KBO. What were the obstacles to equip the ...
LogicBreaker's user avatar
2 votes
0 answers
161 views

How presise could 2 satellites "thread the needle" in orbit?

I have a question about using a magnetic field to propel 2 satellites off each other while traveling in opposite directions on the same orbital plain to intersect either 2:1 or 1:1 on each orbit ...
Muze's user avatar
  • 1
6 votes
1 answer
2k views

What coordinate system was used for the Apollo missions?

This is specifically about the Apollo missions, which are not touched in this related question. Did they use one coordinate system throughout the entire mission, or did they switch depending on the ...
kevin's user avatar
  • 163
11 votes
5 answers
1k views

Is it possible to navigate space travel with no computer?

From launch to land could a person travel in space with only mechanical devices like a sextant? With enough experience what would be the minimum devices needed? Which vehicle currently would be easier ...
Muze's user avatar
  • 1
5 votes
0 answers
1k views

Why would someone use Modified Rodrigues Parameters over Quaternions for spacecraft attitude estimation? And vice versa?

I see quite some papers on spacecraft attitude determination and control, that rely on quaternions. While some others rely on MRPs. The advantage that I see so far is that... for quaternions, the ...
Watch This's user avatar
5 votes
1 answer
224 views

Has a cubesat in LEO determined its orbit and position using only terrestrial cameras plus the Sun? (no GPS, starcam, uplink, magnetic sensors, etc.)

From LEO, a cubesat with several reasonable cell phone-like cameras (or better) can image the Earth and it seems straightforward for some standard pattern recognition algorithms to find the sunlit ...
uhoh's user avatar
  • 149k
4 votes
1 answer
157 views

Help understanding BepiColombo's weak capture at Mercury's L1 and need for delta-differential one-way range measurements

This four-minute BBC podcast Mission to Mercury: BepiColombo spacecraft ready for launch highlights several challenges of the BepiColombo mission, including its orbital-mechanical aspects and is worth ...
uhoh's user avatar
  • 149k
6 votes
1 answer
299 views

What brand and model is the hand-held sextant tested on the ISS?

Astronaut Alexander Gerst is testing an hand-held sextant on the ISS in the context of the experiment Sextant Navigation for Exploration Missions, see picture below. What is the brand and model of ...
Alessandro Jacopson's user avatar
4 votes
1 answer
911 views

How was the Apollo IMU calibrated?

Both the command and lunar modules of the Apollo spacecraft has navigation systems with inertial management units. IMUs are known to drift over time. How were they recalibrated? My answer below ...
DrSheldon's user avatar
  • 48k
2 votes
7 answers
1k views

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 ...
uhoh's user avatar
  • 149k
3 votes
0 answers
97 views

How are Hayabusa2's target markers deployed?

This presentation talks about 'target markers' which are five soft, reflective balls that are released onto the asteroid's surface prior to landing. They allow the probe to more precisely locate the ...
Jack's user avatar
  • 9,966
4 votes
1 answer
328 views

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 ...
uhoh's user avatar
  • 149k
9 votes
1 answer
2k views

Machine Learning and Classical Navigation, Guidance and Control in Space Exploration

Due to the increasing availability of large quantities of data and computational power, machine learning (ML) is providing increasingly better results in various fields. Much research has been done on ...
Yograj Singh Mandloi's user avatar
11 votes
1 answer
897 views

Does the "17" really mean anything with respect to GNSS orbits being rational factions of a sidereal day?

This answer to Why are orbital periods different for different GNSS positioning system constellations? suggests that the orbital periods of the four large GNSSS constellations are linked to the ...
uhoh's user avatar
  • 149k
2 votes
3 answers
575 views

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 ...
uhoh's user avatar
  • 149k
5 votes
1 answer
2k views

Was the Apollo sextant used (or tested) to determine position while in Earth orbit?

The video Apollo Program Guidance and Navigation System 79974 explains that the spacecraft's sextant could be used together with the navigation computer to determine a position fix while in Earth ...
uhoh's user avatar
  • 149k
7 votes
3 answers
1k views

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 ...
uhoh's user avatar
  • 149k
6 votes
1 answer
452 views

Is NICER/SEXTANT the first civilian "spacecraft" to determine it's own position in space without GPS or uplinked data?

Computers on board spacecraft can determine their positions using a combination of uplinked data from the ground and for those closer to Earth, GPS/GNSS. (See this answer and this question for ...
uhoh's user avatar
  • 149k
6 votes
1 answer
165 views

Inexplicable Offset in Satellite Laser Ranging (SLR) observations

I am struggling with the implementation of a Satellite Laser Ranging (SLR) validation tool. The situation is as follows: I am provided with a framework which gives me the position of a SLR ...
lenxn's user avatar
  • 163
9 votes
1 answer
551 views

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 ...
Dragongeek's user avatar
  • 19.2k
5 votes
0 answers
235 views

GPS Receiver Autonomous Integrity Monitoring (RAIM) - parity space method

I am trying to understand RAIM. My teacher explained three RAIM methods, I will just quote all of them because I think that the jargon might not be consistent. Maximum separation / Position ...
MrYouMath's user avatar
  • 151