Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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".

3
votes
2answers
287 views

Could a small enough femtosat/chipsat survive reentry without a heat shield?

Would it be possible to design a tiny satellite, such as a femtosatellite or a chipsat, with such a shape and ballistic coefficient, that it would survive reentry without a heat shield? A bit like ...
1
vote
0answers
83 views

Are there any concrete plans to include chipsats for planetary suicide missions?

One of the potential uses for chipsats may be: Chipsats, which are smaller and cheaper still, are seen as disposable sensors that could be sent on suicide missions to explore hostile environments, ...
1
vote
0answers
883 views

How to calculate a Satellite position at a given time

I am trying to write a program to be able to "model" a Low Earth Orbit satellite's position at for a given time in the future. However I do not have a TLE for the desired satellite, I simply have a ...
1
vote
2answers
202 views

Why are deeper folds better for absorption?

The NASA News item NASA’s New Shape-Shifting Radiator Inspired by Origami describes a technique for spacecraft temperature regulation combining both a shape-changing surface and an emissivity-changing ...
2
votes
2answers
394 views

How are “terminator-riding” sun-synchronous satellites never passing over the pole?

The polar regions won't be missed as they will pass under the sun-synchronous orbit twice a year. – SF. Nov 19 '15 at 9:56 @SF. - Your comment is incorrect. Sun synchronous satellites never ...
2
votes
1answer
773 views

Relation between semi-major axis and radius of an orbit?

From what I understand, the semi-major axis of a circular orbit should be equal to its radius. However, checking Wikipedia's info on Hubble, which is in a nearly circular orbit, I find : sMA $= 6,...
10
votes
3answers
1k views

How well could a satellite hide from Earth detection?

If there are only a few "enemy" radars at known locations that can detect a satellite in LEO, I'd assume there are some radar stealth methods using a spacecraft carefully shaped and oriented such that ...
4
votes
1answer
182 views

Could a cubesat in a 500km SSO orbit effectively monitor earth?

If you were looking for, say, a 1m per pixel quality, what focal length/sensor size would you need? Would there be any off the shelf/commercial solutions?
3
votes
1answer
333 views

Why are deorbited satellites allowed a slow orbit decay instead of burning them up rapidly?

In "What are the conditions for re-entry of an object in a (highly) elliptical orbit?" Eerie asks about orbital mechanics of orbital decay of decommissioned satellite: starting with extremely ...
5
votes
1answer
1k views

Is Transit 5B-5 a.k.a. Oscar 2 really “still kind of 'active'”?

Is there any factual basis for this highly up voted/accepted answer that "Transit 5B-5 a.k.a. Oscar 2 is "still kind of 'active'"? Transit 5B-5 a.k.a. Oscar 2 (not to confuse with OSCAR ham radio ...
1
vote
0answers
89 views

What are relevant missions for CubeSats? [closed]

My high school is planning to launch a CubeSat to the ISS, but we need a mission. A majority of students involved are interested in the engineering aspect of constructing it, and we don't know what it ...
16
votes
2answers
3k views

Why are obsolete geostationary satellites re-orbited above the geostationary belt?

That seems a bit counter-intuitive, because in an orbit above the belt, the satellite would eventually lose gain velocity, so its orbit would intersect the orbital plane of the geostationary ...
2
votes
1answer
134 views

Why is the velocity of a satellite the result of a sum of two velocities? (clarifying img included)

I am a newbie when it comes to orbital mechanics. The velocity of a spacecraft is given by a sum of two types of velocities. But I don't understand the difference between both velocities: $V = V_{кр}...
3
votes
2answers
824 views

Is it possible for small satellites to orbit in MEO or GEO?

I am researching satellite technology, and in particular I am looking at the rise and implications of smallsat technology. As far as I know, there are currently no satellites beyond LEO that would be ...
7
votes
1answer
695 views

Blue region in satellite image

In one BBC article called "Etna escape: 'Pelted with the deadly, hot debris'", there was an image with the following description: Europe's Sentinel-2a satellite pictured Thursday's lava flow from ...
1
vote
1answer
229 views

Characteristics of the modern satelite radio transmitters

I'm trying to find some data concerning current Earth-satellite radio communication systems, namely general characteristics of the equipment currently used on satellites. Specifically, I'm interested ...
7
votes
1answer
1k views

How stationary is geostationary?

When a satellite is in geostationary orbit, it is supposed to stay above one spot of the earth and rotate around the earth at the same rate the earth spins. But how exact does that equality need to be?...
2
votes
2answers
2k views

Height of navigation satellites above Earth

What is the distance between the Earth's surface and the motorists' satnav satellites?
4
votes
2answers
268 views

Commercial grade single board computers (SBCs)

Suppose a nanosatellite is made with several commercial grade SBCs working together. And we design it so as to give output based on majority voting type of algorithm. I am aware of single event upsets ...
13
votes
1answer
3k views

How much will SpaceX's constellation of Internet satellites cost?

SpaceX has a plan to launch up to 4K satellites to provide global Internet access. Is there a reasonable estimate of how much this constellation would cost to launch? Also, as the minimum number of ...
7
votes
1answer
235 views

SpaceX 2nd stage or tumbling satellite? WSW to NE over FL

Around 2040 EST We viewed an irregularly flashing object flying from WSW to NNE (roughly) from Jacksonville FL. Is the SpaceX 2nd stage still up there and if so, would it be tumbling and visible? Is ...
6
votes
1answer
265 views

ISRO's PSLV-C37 with 104 satellites - after 56 hours only six TLEs, which factor is greatest challenge?

It's been 24 hours 56 hours since ISRO's PSLV-C37 launched from Satish Dhawan Space Centre (SRI) at 09:28 local time (03:58 UTC). I see satcat numbers and object names for 105 total objects; ...
5
votes
1answer
399 views

Why are spy satellites in elliptical orbits?

This answer mentions that (optical) spy satellites are often in elliptical orbits, and when I look here sure enough the orbits are elliptical, with periapsis altitudes around 250 to 400 km, and ...
5
votes
2answers
527 views

What is the final conclusion about 'object M'? What happened?

I've looked at Is Iridium launch object M a test satellite? and I don't understand what seems to have happened. The Iridium launch produced 11 orbiting objects when only 10 Iridium satellites were ...
16
votes
3answers
2k views

Do companies/governments ever sell satellites that are already in space?

Do companies/governments ever sell satellites that are already in space to other companies/governments for use? I'm wondering about the sale of the actual physical satellites. Has it ever happened? Is ...
5
votes
1answer
825 views

How were the 10 Iridium NEXT satellites deployed by SpaceX?

Can someone explain (in general or specific terms) how SpaceX deployed these 10 satellites? I'm trying to imagine the mechanisms and process of launching these objects with the required precision. Is ...
12
votes
1answer
3k views

Why did early satellites (e.g. China's Fanhui Shi Weixing) re-enter the atmosphere narrow end (nose)-first?

I was surprised to find out from @JohnnyRobinson's new answer that China's series of Fanhui Shi Weixing spacecraft (FSW) used impregnated oak heat shields. I found this in astronautix: The capsule ...
1
vote
3answers
396 views

Why don't signals from rovers on Mars get lost on the long trip to Earth? [duplicate]

I read that there is a satellite orbiting Mars that the rovers send data to but I still find it amazing how that satellite can send signals tens of millions of miles to earth without any ...
8
votes
3answers
231 views

Are transfers between two orbits commutative?

Are the propellant mass and transfer time from orbit A to orbit B the same as from orbit B to orbit A, considering low-thrust propulsion? That is, in the case of dealing with Keplerian orbit ...
3
votes
1answer
866 views

How much fuel is being consumed by all spacecrafts in orbit?

It is possible to supply spacecrafts in orbit in cis-Lunar space with oxygen from fuel production facilities on the Moon or on asteroids. What is the size of this potential in-space oxygen market ...
6
votes
1answer
117 views

What are the economics of upgrading versus refueling satellites?

It is sometimes suggested that fuel produced on the Moon or on asteroids could be launched more cheaply to dock with and refuel for example communication satellites in GEO to extend their operating ...
6
votes
2answers
2k views

In “spacecraft talk” is nadir just a fancy word for “down”?

Assume the approximation that the Earth is spherically symmetric — without higher order gravitational multipoles, and other effects that might be related to gravity from other bodies or the ...
6
votes
1answer
365 views

Which two satellites had a 44% probability of collision at 2017-01-07 21:53 UTC?

I saw this message on space-track.org: The JSpOC has identified a close approach between two non-maneuverable satellites in a sun-synchronous orbit (approximately 800km altitude) with a time of ...
6
votes
2answers
383 views

Puzzler: Is this a Sputnik?

I was enjoying the Trailer to the YouTube site Kinematic, and I noticed that the satellite or model shown in the beginning looks different than how I remember the original Sputnik - specifically the ...
3
votes
1answer
268 views

Deorbit LEO debris with a higher orbit laser?

A couple of days ago I asked Can a laser be used to clear the launch path of a rocket? turns out this is not a good plan but the answer by Hobbes suggests the idea of clearing debris with a laser is ...
1
vote
1answer
227 views

Can a laser be used to clear the launch path of a rocket?

Military grade lasers shooting down incoming missiles have been in the news since Ronald Reagan was the US president. The problems, as I recall are mostly about diffusion in atmosphere. The Kessler ...
-2
votes
2answers
633 views

Why the different satellites have different orbits? [closed]

There are many satellites revolving around earth, then why any $2$ of them collide to each other.$$OR$$ Why all of them have different orbits? What the scientists do to separate their orbits so that ...
7
votes
2answers
295 views

Was a commercial (ad) balloon satellite ever deployed?

I remember hearing a story from some two decades ago, about a publicity stunt by one of the two - can't remember which - Pepsi or Coca-Cola. The action was allegedly deployment of a gigantic balloon ...
6
votes
1answer
344 views

How long does it take for ISS to travel over all possible places of the world one time?

ISS has an inclination of about 56 degrees but because his orbit is not exactly a whole part of 24 hours, ISS will the next day be above other places. So after a while he has 'visited' most of the ...
30
votes
5answers
4k views

Is it possible to see animals from space?

Will satellite imagery be able to see the backs of big animals such as lions, tigers, elephants, horses or zebras from space when they venture out in the open? I've not been able to find satellite ...
13
votes
1answer
1k views

How are remove before flight (RBF) pins made?

The CubeSat standard (CubeSat Design Specification Revision 13) requires that CubeSats have a remove before flight (RBF) pin that "shall cut all power to the satellite once it is inserted into the ...
10
votes
2answers
412 views

How can just making the ground broadcast stronger neutralize a zombie(sat)?

In April of 2010 the Geo-not-so-stationary satellite Galaxy-15 stopped responding to ground commands. It operates as a "bent-pipe" or Transponder system, which means - roughly speaking - it will ...
5
votes
0answers
86 views

Which robotic spacecrafts have autonomous operation capabilities?

I am searching for an overview of autonomous space robots integrating motion planning capabilities, such as a list of robots (past and present). So far, I have found these robots: Mars exploration ...
8
votes
2answers
4k views

How do rockets avoid satellites?

From this question we know that there are quite a few satellites orbiting Earth. But how do ESA and NASA avoid their rockets colliding with these satellites (is there some kind of database of (man-...
1
vote
2answers
701 views

What is the limit of bandwidth of a satellite in LEO and what determines that

How much uplink capacity (in terms of GB per day) is typical for a satellite in LEO? What aspects determine how much data can be transferred back to the earth?
3
votes
3answers
521 views

curious to know about artificial satellites orbiting moon

I took this pic on 16 th November 2016 two days after supermoon using a small telescope and accidentally captured some sort of satellite pic along with the moon.i am curious to know howmany such ...
6
votes
2answers
188 views

Why will GOES-R take a whole year for validation?

I've been reading a few things about NOAA's GOES-R satellite, and I noticed this on the GOES-R site: ...will be placed in the 89.5° checkout orbit where it will undergo an extended checkout and ...
1
vote
1answer
369 views

How will GOES-R simultaneously point some instruments down at Earth and others sunward?

GOES-R is scheduled to launch soon and put in geostationary orbit over North America for high bandwidth continuous monitoring of Earth, with only 120 minutes per year interruptions caused by ...
0
votes
2answers
491 views

Why are there so many satellites around the moon if they are blocked out of radio communication half the time?

They state there are about 500 or so satellites orbiting around the moon. However according to NASA back when they said we landed on the moon, when the astronauts orbited around the dark side of the ...
1
vote
0answers
80 views

Was a satellite ever brought back to earth and then launched again? [duplicate]

Today I was reading a children's book (Ich hab einen Freund, der ist Astronaut ... my translation: "I have a friend who's an astronaut") to my son. On one page it claims that (translation by me): ...