Questions tagged [artificial-satellite]

Questions about objects in orbit which are human made, such as communications and GPS satellites, orbital observatories and space stations, and other man-made object in permanent or semi-permanent orbits around the Earth, other celestial objects, aside from the Sun, or even other satellites. Not to be confused with non-orbited man-made objects in space, that are usually referred to as "probes", or simply "spacecraft".

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1answer
70 views

Was there a spacecraft that was clearly the first to be put in a polar orbit?

Was there a first spacecraft put in a polar orbit? It might not be clear if it's too hard to say what high inclination orbit is or is not polar, for example if 91 satellites were launched in 0, 1, 2.....
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1answer
68 views

Use of carbon nanotube based black colourings like Vantablack in space

I've seen several articles talking about the ways in which Vantablack and similar substances could be used in space as a replacement for black paint. For example, they could be used on the optical ...
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1answer
901 views

Why does Himawari-8 have problems with the Sun from 19th February to 19th April?

This weather site uses provides meteorological imaging from the Himawari-8 Earth observing satellite in GEO. https://www.cwb.gov.tw/eng/ The web site contains the following item: ...
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What percentage of a satellite's total budget goes into its launch?

Been trying to do some personal market analysis of the space market, and realized that there doesn't seem to be any kind of statistic or average regarding how much percentage the launch of a satellite ...
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1answer
102 views

What did Sputnik-1 sound like? Did it use multiple tones?

Radio transmissions from Sputnik-1 could be heard on short wave radios around the world. Questions: A carrier signal only would not be particularly audible to an AM radio listener, was it modulated ...
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146 views

What was the first use of analog to digital conversion in a satellite?

This answer to Do the Voyager probes transmit analogue or digital data? states that the Voyagers sent only digital data. This is no doubt mostly because analog data was digitized and store digitally ...
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How to see Iridium Flares (if possible) in 2020 and beyond?

On December 27th, 2019, Iridium 97 burned up in the atmosphere and there was a "#Flarewell" celebration. However, according to this website which seems to be VERY detailed, there are still 5 ...
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3answers
268 views

How fast do Starlink satellites (SpaceX new satellites) rotate around the earth?

I'm specifically interested in knowing how long they take to do a full circle around the earth but don't find any info. Could anyone help me?
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How can I plot satellite's trajectory from three different TLEs to detect any deviation on path with time?

I have obtained TLE information of a satellite from space-track.org for three different times. I am trying to study any deviation of the satellite trajectory from its usual path. Here I am comparing ...
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1answer
453 views

What does “MSR” represent in the context of this predicted satellite conjunction?

In a series of four tweets starting with this one (found in 2 satellites will narrowly avoid colliding at 32,800 mph over Pittsburgh on Wednesday) 1/ We are monitoring a close approach event ...
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1answer
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How did two satellites end up in almost the same orbit except moving in opposite directions?

In a series of four tweets starting with this one (found in 2 satellites will narrowly avoid colliding at 32,800 mph over Pittsburgh on Wednesday) 1/ We are monitoring a close approach event ...
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1answer
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Why does it take Spaceway 1 (satellite) two or three months to dump 73 kg of bipropellant?

I read on https://arstechnica.com/information-technology/2020/01/directv-races-to-decommission-broken-boeing-satellite-before-it-explodes/ (mirror): In the time available, DirecTV said "it will be ...
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1answer
152 views

Why is “Terminator Tape” electrically conductive?

A 230 foot long tape deployed from the satellite Prox-1 greatly reduced how long it took to deorbit. The tape was described as electrically conductive. Was that property intended to help the ...
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How do two-line element sets handle rev numbers > 99,999?

In a two-line element set (TLE), five characters in line 2 -- columns 64-68 -- are for the rev number. (https://en.wikipedia.org/wiki/Two-line_element_set) But some satellites have been around the ...
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232 views

Why is the NORAD Catalog number of SpaceX's Starlink's “Darksat” both 71130 and 44972?

@BowlOfRed's answer to Which of the recently launched Starlink satellites is the coated one? links to Celestrak's supplemental table for Starlink. https://celestrak.com/NORAD/elements/supplemental/...
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How are rocket launches scheduled?

With all the satellites and other objects already in space; how exactly are launches scheduled and coordinated? Is there some kind of clearinghouse? How do the mega constellations affect the ...
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1answer
86 views

Analytical treatment of relative positions between satellites?

I have been searching the internet for estimation of relative position between two satellites. However, all sources seem to be pointing to methods used for proximity operations, where the math ...
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1answer
47 views

Extraction of elevation data from ICESAT-2 dataset

I need icesat2 elevation data for DEM validation process. I have been trying to extract elevation data only from icesat-2 dataset that i downloaded from earthdata but unable to successfully extract ...
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What is the proper terminology for the process of a satellite entering a planet's shadow? [closed]

What is the proper terminology for when a satellite or spaceship passes into a planet's shadow or night side? Is it crossing the terminator? Passing into eclipse (or something better)? If there is a ...
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1answer
110 views

What Earth satellite remained in orbit the longest before reentering?

@BillGray's excellent answer in September 2018 mentions that the Soviet magnetospheric research satellite 1977-093A (NORAD 10370) was expected to reenter the atmosphere in 2019 due to effects ...
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2answers
416 views

What is the reason for secondary oscillations in apogee and perigee plots for objects 41332 and 41333?

This answer provides quite interesting plots of apogee and perigee for objects 41332 and 41333. The primary (sine wave -like) oscillations are probably due to perturbations caused by potential ...
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1answer
553 views

Can dust be in orbit around a spacecraft which orbits the Earth or Moon?

In the title above, Can dust be in orbit around a spacecraft which orbits the Earth or Moon? let's define "in orbit" to mean gravitationally bound to the spacecraft long enough to go around it a few ...
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1answer
109 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 ...
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2answers
198 views

Building the ISS LVLH frame in ECEF/ITRF coordinates

I am trying to calculate the International Space Station (ISS) LVLH (Local-Vertical-Local-Horizontal) base vectors expressed in the ECEF/ITRF frame at a given time. The point is then to calculate the ...
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How do the Starlink satellites shine?

As we can see the Starlink satellites with the naked eye as they pass by. I was wondering about what makes them visible. Do they have large mirrors that reflect the sunlight making them look as if ...
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2answers
542 views

Do they actually regularly send out people with space ships to spacewalk out and fix broken satellites?

I have an extremely limited understanding on how many people have been "in space" (at least in orbit around Earth) and how many people go there every year/month/week(?). It could be 1 per year or 100 ...
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1answer
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ISS attitude yaw pitch roll conventions. Which one to use?

I found three definitions for the attitude angles of the ISS (yaw, pitch and roll), from three different source. They contradict each other. See the following pictures. For my problem, I have to ...
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2answers
80 views

What is the most likely range of orbits for on-orbit servicing satellite?

An on-orbit servicing satellite (OOS) is one what would be use for servicing, refueling, assembly in space. Would there be any specific orbit or standard orbit or at least most-likely range of ...
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1answer
59 views

Two line element set

I was wondering where I could find the TLE of a satellite ( I am looking for CASSIOPE). I went into this link - https://www.n2yo.com/satellite/?s=39265 but it has only got the most recent updated TLE. ...
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1answer
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What exactly is SL-24 DEB (2010-028D)?

After 3 months of work I've been able to spot satellite debris with my 20x80 binoculars for the first time. The object in question is SL-24 DEB (2010-028D). According to the data presented in www.in-...
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1answer
4k views

Could a Falcon Heavy really put six GPS Block III satellites in orbit at the same time?

This answer says: GPS Block III satellites are being launched to replace failed or aging Block II satellites, which doesn't require launching more than one at a time. A Falcon Heavy could fill up ...
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Satellite spotting

My normal activity in early morning and evening is to count how many satellites I can spot which is between 5-7. At 6 am on 22nd November I counted 51 all in single file some 3 abreast; it was ...
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3answers
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Why is one Starlink satellite not following the adjacent one in this image?

The following image shows trails of SpaceX’s Starlink satellites as seen in the sky above the Cerro Tololo Inter-American Observatory (CTIO) in Chile: Image Source: SpaceX’s Newly Launched Starlink ...
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1answer
55 views

Working principle of earth sensor

In satellite systems to derive attitude sometime earth sensor is used. This basically outputs two axis information which when combined with orbit knowledge and sun vector from the sun sensor provides ...
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3answers
219 views

Why are the poles of the Moon in Google Earth so different from other regions?

I am well aware of the fact that the poles of the Moon are different from the rest of the regions in many ways. But in Google Earth's Moon, the poles are so different from what we would see if we were ...
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3answers
680 views

Why is the Duration of Time spent in the Dayside greater than that of the Night side of the Moon for Chandrayaan-2 Orbiter?

The following information is from ISRO's webpage on "Detection of Argon-40 in the lunar exosphere" (Textual information relevant to my question is in bold face): The Chandra’s Atmospheric ...
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1answer
2k views

Commercial satellite retrieval - possible?

I know that the space shuttle was originally designed with the capability to retrieve satellites from space, but I'm wondering if in the commercial market right now if there are services that allow ...
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0answers
87 views

How to satellite-to-site range given site coordinates and satellite ephemeris?

How can I calculate the distance of a position on earth to a satellite (for example a GPS satellite)? The satellites position is exactly known by its ephemeris data. In a related question I've asked ...
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1answer
137 views

How exactly does atomic oxygen cause problems for spacecraft in VLEO?

In very low Earth orbit there are (at least) two problems; aerodynamic drag, and atomic oxygen (O rather than O2). Drag can be compensated with a low thrust from an ion engine. Question: But what ...
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2answers
156 views

Do satellites in orbit undergo translational motion or rotational motion, when initially they are not given any additional spin?

Regarding the proposed duplicate: Thought the proposed duplicate has a similar titIe, I have read those answers and this question requires a different answer. We know satellites orbit around Earth, ...
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1answer
91 views

Inclination maneuvers for GEO satellites

I was wondering about the orbital location to perform inclination nulling maneuvers for GEO satellites. I know from basic astrodynamics that the best place to perform inclination correction is at ...
7
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1answer
199 views

How has the brightness of SpaceX's Starlink constellation changed since May?

Shortly after the launch, before full orientation of the solar panels and raising of the orbits, the Starlink satellites were surprisingly bright and easily seen with the naked eye. Back then, I heard ...
6
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1answer
597 views

How to calculate the force required to maintain a 10 km diameter disc in a low 80 km orbit?

What force (in the form of periodic impulses) is required for thrusters (thermochemical, electrical, electromagnetic, ionic. Photonics, Hall) to keep such a disk in orbit (80 km) above a fixed point ...
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51 views

Predicting non-Iridium flares and Why NOSS satellites flare?

I just saw two point-like sources flaring in the sky in perfect sync. It was spectacular and a big surprise to me. The full event lasted at most 4 seconds. My position is in the Usera district in the ...
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1answer
141 views

What is the purpose of orbital frame of reference for a satellite orbiting the earth?

Orbital frame of reference: a frame of reference with its origin on the orbit and x-axis pointing towards the velocity vector and z-axis towards the center of mass of the earth. the y-axis completes ...
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1answer
74 views

Could any “Well-Tracked Analyst Object” turn out to be a natural object or even something else?

The excellent satellite tracking database www.space-track.org, which is mantained by the United States Space Command, offers to the public accurate and up-to-date orbital elements for thousands of ...
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1answer
84 views

What are those tilting/rotating platforms called that hold spacecraft during assembly, testing, and sometimes transport? [duplicate]

The first image from the BBC's Euclid space telescope to study 'dark Universe' makes progress reminded me of the second two, which are taken from What are these air-vent-like structures on this ...
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40 views

Parallax calculation

Given two points of observation on Earth (obs1=[lat1,lon1], obs2=[lat2,lon2]) and the apparent azimuth and altitude of a target from these two locations ...
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3answers
174 views

How is the brightness of satellites measured?

We would like to perform measurements of the brightness of Starlink satellites. Is there any approved technique available ? I see the name Mike McCants connected with magnitude values of ...
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2answers
4k views

In what state are satellites left in when they are left in a graveyard orbit?

I had this idea for a fictional scenario in which a forgotten satellite, like a communications satellite that was decommissioned because it was replaced by a newer model, was hacked into and then ...

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