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6 votes
1 answer
185 views

How do engineers measure satellite drag, and how do they track it over time?

I’ve been slowly getting myself familiar with astrodynamics and understanding satellite orbits. I’m familiarizing myself with the concept of drag experienced by the satellites. I am curious about how ...
AGS's user avatar
  • 277
0 votes
0 answers
74 views

How to compute the pointing accuracy

I was wondering if there's an equation or somewhat intuitive way of computing the pointing accuracy of a satellite? What parameters do I need and how would I go about it?
Lez's user avatar
  • 1
12 votes
3 answers
3k views

Would electrically powered thrusters on JWST have made it last for decades longer?

Since the lifespan of the James Webb Space Telescope is determined by the amount of fuel it can carry for its thrusters, used to decelerate the reaction wheels used to orient the telescope, and since ...
Ryan Christiansen's user avatar
5 votes
1 answer
172 views

Given historical TLE’s, how do I determine the path/orbit/LLA of a satellite for a given historical period?

Im trying to get the historical Lon/Lat/Alt of a starlink satellite. I'm using TLE's from space-track and Skyfield to calculate latitude, longitude and altitude of satellites for a given date range. ...
AGS's user avatar
  • 277
2 votes
0 answers
57 views

EPS sizing for lunar mission

As part of a university project, I am working on EPS sizing for a mission to the lunar environment. I have sized the SA and batteries, chosen the components and the PDCU; however, having never been in ...
andrescpa's user avatar
3 votes
0 answers
186 views

Why do ~GEO sats seem to cluster around the top portion and bottom portion of the belt, 180 degrees apart?

I made a 3D tle model from https://www.space-track.org/ API. I drew a dashed blue line to show the really "geo" orbits that hardly move with time (ECEF). Then there are a bunch of sats that ...
Krits's user avatar
  • 31
1 vote
1 answer
123 views

How can I get a list of GNSS satellites in view for a given date/time

I need to generate a list of which satellites were in view at a given date/time. I'm specifically interested in the Galileo constellation of GNSS satellites, and I'd like to get a list of when each ...
Tim Long's user avatar
  • 113
4 votes
1 answer
204 views

Why did SpaceX change Falcon 9’s engine configuration?

Why did the Falcon 9 go from a 3x3 configuration to a ring of 8 around a central engine? Was there some sort of aerodynamical advantage to be found or something? https://en.wikipedia.org/wiki/...
Blue Skin and Glowing Red Eyes's user avatar
2 votes
1 answer
146 views

Selfie from space with AWS Groundstation

I hope this question fits this community! While browsing r/AWS today I read about someone who was able to make a "space selfie" with AWS Groundstation: The progress is detailed further down ...
RAD6000's user avatar
  • 1,158
0 votes
0 answers
62 views

How to "turn off" ADCS system to monitor orientation after firing MDT's?

I've been tasked in a hypothetical mission of determining if an Attitude Determination and Control System (ADACS) can be "turned off" during MEMS Digital Thruster (MDT) firings so that the ...
Blake Fielder's user avatar
4 votes
2 answers
159 views

How could a spacecraft reduce an orbital insertion burn after a Hohmann transfer using gravity assists?

I want to calculate a mission to Saturn, and my theoretical spacecraft has a total Delta-V of about 10,000 m/s. I have seen using different tools that it will take about 6000 m/s for the initial ...
Daniel Shepherd's user avatar
3 votes
1 answer
436 views

How does the current or future network latency of SpaceX Starlink compare to wired internet?

When reading about SpaceX Starlink, high frequency stock traders are mentioned as a potentially lucrative customers, this is because satellite to satellite communications don't have glass between them ...
moshevi's user avatar
  • 479
6 votes
0 answers
233 views

How do spacecraft protect their engines from micrometeroids?

A meteoroid impact on an engine bell can easily rupture a coolant pipe. Or it can create an imperfection in the backing plate from where cracks can form. Or it can destroy an injector. All of these ...
Abdullah's user avatar
  • 2,615
1 vote
2 answers
149 views

Deep space mission propellant

For an interplanetary mission that has a duration of 40 years cam we use hydrogen peroxide monopropellants? Can we use arcjets?
RemyJ's user avatar
  • 11
12 votes
1 answer
3k views

Was there any truth that the Columbia Shuttle Disaster had a contribution from wrong angle of entry?

The principal of my tiny school in Japan was presenting to a student to suggest he make a speech on the Space Shuttle's reentry aspects. He included newspaper articles on the Columbia space disaster. ...
user2617804's user avatar
2 votes
1 answer
157 views

How do I calculate the maximum northern and southern latitude a LEO satellite can image?

How do I calculate the maximum northern and southern latitude a LEO satellite can image? What parameters would I need?
pottie's user avatar
  • 21
2 votes
1 answer
90 views

How to model the gravity of Titan in GMAT

I would like to know how to find the gravity file (.cof) for Saturn's moon Titan. Need this to model the gravity field of Titan.
D P's user avatar
  • 53
2 votes
1 answer
135 views

Propellant choices for a Mars landing; tradeoffs between LOX/CH4 and H2O2/RP-1?

What are the tradeoffs between LOX/methane and peroxide/kerosene for a Mars landing mission? In which ways are each better or worse than the other? I think the second one would more attractive for ...
Hartsfield's user avatar
1 vote
0 answers
47 views

Use local acceleration and angular velocity to calculate rotation matrix

Can I ask if there are any python packages that can fuse local acceleration and angular velocity and get rotation matrix? Thank you!
percy_liu's user avatar
0 votes
0 answers
16 views

Receiver location calculation based on Rinex navigation and observation files [duplicate]

I am trying to calculate the location of the GNSS receiver using the data available in the Rinex navigation and observation files. As a first step I am trying to calculate the pseudo range using the ...
SAG DAG's user avatar
6 votes
1 answer
506 views

Is it possible to open and close ROSAs several times?

During the preliminary phase of designing a REUSABLE lander for the lunar surface from the gateway, the need to necessarily use deployable SAs came up. In addition, because of the descending and ...
alespacerfed's user avatar
2 votes
1 answer
216 views

Size of sugar rocket to reach space (suborbital)

How much propellant would an ideal single stage sugar rocket with dry mass of 1 kg need to reach the altitude of 100 km in a suborbital flight when launched straight up? Let us assume the specific ...
Kozuch's user avatar
  • 1,403
2 votes
1 answer
126 views

Inflatable tank/balloon use for recovery

Hopefully this idea makes sense. Basically if you've seen the space-truck (ROOST), you'll get where I'm going with this. I'm wondering whether an inflatable tank/tank lining could be used to produce ...
Anti Elon Guy's user avatar
2 votes
1 answer
134 views

Accidents where discarded stages are propelled by vaporized propellant?

Falcon 1 flight 3 failed when propellant vaporized in the detached first stage's engine, causing it to slam into the second stage. Has this happened to any other launch vehicle? Do launch vehicles ...
Abdullah's user avatar
  • 2,615
0 votes
1 answer
90 views

Running and editing GMAT script files from MATLAB

I am trying to run a design optimisation proccess for some orbital parrameters of spacecraft. To do this, I need to be able to edit and run a GMAT script from MATLAB. Is this possible? If so, how ...
Lee's user avatar
  • 11
7 votes
5 answers
5k views

Why doesn’t SpaceX sell Raptor engines commercially?

I have never studied rocket science and am just curious about this. I would assume one Raptor 2 engine could launch a small rocket to space. I heard they are able to make them for less than a million ...
user51440's user avatar
1 vote
1 answer
155 views

Where can I find ephemeris data (up to date) for any of LEO satellites?

A bunch of websites have live tracking of satellites, e.g. this one. Where are they getting the satellite ephemerides data for all of the iridium satellites?
AGS's user avatar
  • 277
0 votes
0 answers
89 views

How to estimate the fuel required to send 1 kg to lower mars orbit?

Imagine a rocket with a payload of 1 kg. How much liquid fuel would be required to send that 1 kg payload to lower mars orbit. (1 kg is just the payload not the whole dry mass of the rocket) I want ...
Shardul's user avatar
2 votes
1 answer
120 views

Is specific impulse and thrust maximum in vacuum or for exit pressure equals atmospheric pressure?

According to the thrust formulation of a rocket one can show, that maximum thrust is not delivered for pambient= 0 but for pambient=pnozzle_exit since then the momentum term is maximized. But then I ...
Kevin's user avatar
  • 29
1 vote
1 answer
204 views

What is the difference between these two Universal Gravitational Constants? [closed]

Can someone please help understand when to use each of these Universal Gravitational Constants. G = 6.67 x 10-11 N•m2/kg2 G = 6.67 x (10^(–11)) N(m^2) (kg^(2)) compared to G = 6.67 * 10-11 m3/kg-1s-2 ...
Nicholas Piccirello's user avatar
5 votes
3 answers
260 views

How obvious would an Earth-like planet be when searching for signs of life in space?

If a planet nearly identical to Earth were orbiting a nearby star, how obvious would it be to us, using our current efforts to search for signs of life? Would it stick out like a sore thumb? Or ...
Wyck's user avatar
  • 1,584
11 votes
3 answers
2k views

Could a Nuclear-Thermal turbine keep a winged craft aloft on Titan at 5000m ASL?

It's what it sounds like: Given the output of the NASA nuclear reactor (the one they're going to use for the Artemis program), and the use of an electric-motor-driven turbine system, how feasible is a ...
Anti Elon Guy's user avatar
1 vote
1 answer
181 views

What is the chance that there is atleast one water molecule in a given volume of space [closed]

If you imagine a single cubic meter, and place it anywhere in space, in any orientation and take any two opposite faces of the imaginary cube, and stretch them to both edges of the universe; what is ...
anderio Moga's user avatar
12 votes
2 answers
1k views

Rocket Engine Failure Rate

I am a reciprocating engine machinist and understand that rocket engines are much much more complex. But I am curious why they have such a high failure rate. Even modern rockets are designed to ...
still_learning's user avatar
2 votes
2 answers
218 views

In theory, could this redesign of the launch profile reduce fuel use? [duplicate]

This is a purely theoretical question, because I suspect that trying to build a launch system of this sort would pose its own set of very complex problems. That said, the Wikipedia page for the ...
dgnuff's user avatar
  • 131
7 votes
2 answers
139 views

Would a laser seismometer work from lunar orbit?

Lasers today have become extremely sensible, they can detect sub-millimeter movements of a surface from a distance. Could this feature be exploited to create a lunar seismometer working from a probe ...
FluidCode's user avatar
  • 191
14 votes
2 answers
1k views

What is this small white device with LCD and 10 keys on the International Space Station?

I see this device in many places in International Space Station; what is it called and what does it do?
Ahmed El-Bermawy's user avatar
2 votes
1 answer
162 views

ISS (ZARYA) TLE to Latitude Longitude Conversion

I am trying to take TLE of ISS (ZARYA) and get the latitude longitude and height. I am aware the TLE is in TEME~(True Equator Mean Equinox) frame. This means that the TLE was generated considering the ...
zephyr0110's user avatar
  • 2,921
5 votes
1 answer
126 views

"Received power" on NASA's DSN web page

Out of curiosity, the "received power" shown for a spacecraft on NASA's "DSN now" web page 1 - is that at the receiver, or at the antenna? I'm looking at one of the antennas now ...
ELaw's user avatar
  • 51
17 votes
2 answers
1k views

What kind of heating would occur during a suborbital re-entry?

What kinds of peak temperatures would a stage similar in proportions to the Space shuttle with a similar belly-first approach experience when re-entering from a low suborbital trajectory (similar to a ...
XBN's user avatar
  • 179
4 votes
1 answer
127 views

Would Li-Ion batteries for a lunar base energy storage system be transported to the base charged or uncharged?

I'm investigating lunar base power systems and energy storage systems (ESS). One option is photovoltaics (PV) and Li-Ion batteries. A large mass of batteries would be required to power the base during ...
nwsteg's user avatar
  • 143
2 votes
1 answer
103 views

How is stage 2 propelling the spacecraft forward? [closed]

A decent response on how the burning process works but how does this glowy burner push the spacecraft
rick's user avatar
  • 29
22 votes
4 answers
4k views

How do space probes find their way and how much fuel do they use to travel?

How do space probes find their way, for example, to explore dangerous planets like Jupiter or Saturn that have powerful magnetic fields? Do scientists control it from stations in NASA or they have a ...
C.F.G's user avatar
  • 329
6 votes
1 answer
1k views

What amount of unburned methane was released in the atmosphere during the Starship orbital test abort?

On April 20, 2023, SpaceX attempted an orbital flight of the Starship rocket. The test ended when the Flight Termination System blew up the rocket after it started tumbling out of control. When the ...
Speedphoenix's user avatar
  • 5,324
4 votes
1 answer
125 views

What are the safe structural elements of spacecraft that could be used for on-orbit capture?

I know this depends on the general configuration of a spacecraft, but I am hoping to gain some insights. Assuming you have a servicer spacecraft with an abstracted capture mechanism (i.e., end ...
Ibrahima's user avatar
21 votes
3 answers
5k views

Why will Starship's 150 ton payload capacity be sufficient to carry 100 people to other planets?

The ISS weighs 450 tons and carries 7 people for three months without resupply. Starship is supposed to carry 14 times as many people for more than twice the duration with one third the mass. How?
Abdullah's user avatar
  • 2,615
2 votes
0 answers
74 views

Where exactly are the BE-7 engines on the Blue Origin HLS for Appendix P?

I was reading about the recent selection of Blue Origin for a second Lunar Lander, and a comment on an article caught my eye. Where exactly are any of the engines on the new lander? Here you can see ...
fyrepenguin's user avatar
  • 1,329
5 votes
1 answer
320 views

Ariane 6 upper stage schematic showing integration of APU

I've been reading about the Auxiliary Power Unit (APU) on the Ariane 6 upper stage and am looking for a schematic showing how it's integrated into the stage. From Thermal Control of the Cryogenic ...
Organic Marble's user avatar
1 vote
1 answer
104 views

Distance between Sun and Earth using JPL horizons

Using the JPL Horizons app at https://ssd.jpl.nasa.gov/horizons/app.html#/ would someone help to calculate the distance between the Sun and the Earth say 1 May 2023 00:00 UT? I used the following for ...
Smarty's user avatar
  • 31
0 votes
2 answers
216 views

Orbit prediction for satellites using the Kepler model

I would like to know how to model the motion of satellites in orbit using Keplerian, i.e. develop a simulation model that tracks paths of satellites using Keplerian orbits in Python?
Racky Alvin's user avatar

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