All Questions
18,479
questions
3
votes
1
answer
100
views
How is roll alignment achieved by the Soyuz docking mechanism (SSVP)
The best description of the Soyuz docking system I could find is in the proceedings of the 6th Aerospace Mechanisms Symposium (scroll to PDF page 139, labeled page 143). The alignment process is ...
- 8,747
0
votes
0
answers
16
views
What are the challenges of in-orbit refueling?
Is it possible with current technology and has it ever been tried? Are there dangers of the connector breaking or fires? Could mid-air refueling done by fighter planes be adapted for this? Has any ...
- 313
-2
votes
0
answers
54
views
Iridium satellites renaming [closed]
I somewhat understand historical renaming of the Iridium satellites like e.g.
Iridium 20 → Iridium 920 (24871 / 1997-034C),
but what about:
Iridium 24 ↔ Iridium 46 (24905 / 1997-043C, 25105 / 1997-...
- 97
4
votes
1
answer
186
views
What is the significance of a heat flux value of 1135 W/m^2 when jettisoning the payload fairing?
I have seen that many rockets jettison their payload fairing at an altitude where the aerothermal heatflux is leass than or equal to 1135 W/m^2. What is the reason behind considering this particular ...
1
vote
0
answers
56
views
Where can I find the video of Apollo 16 floodlight mistaken with a UFO?
So, a few years ago (2004) NASA showed that a picture of a supposed UFO captured by the Apollo 16 astronauts through the window of the Command Module was in fact the floodlight protruding from the ...
- 2,431
9
votes
1
answer
610
views
Why does the Psyche Spacecraft use cold gas thrusters?
In a recent article on SpaceNews they write
[There exist] nitrogen cold-gas thrusters that orient the spacecraft.
This seems like an odd choice for me, considering it is a multi year mission that ...
- 8,747
5
votes
1
answer
182
views
How does NASA ensure nobody else communicates with probes? [duplicate]
We often hear about how various parts of Voyager have been turned off or on, or how course corrections have been made.
How does NASA know that nobody else on Earth can send instructions to a probe? It ...
- 2,209
0
votes
0
answers
34
views
How many tonnes of cargo are stored on the International Space Station?
I think I read somewhere that SpaceX's Starship should carry 100 tonnes to the moon, and that this amount of mass was greater than the total cargo on the ISS, but I can't find a reference confirming ...
- 703
2
votes
1
answer
84
views
Can I move Hyperion to Mars with fusion rockets?
I'm working on a SciFi story set roughly in 2100 that takes place both on the moon and Mars. One plot point hinges on terraforming Mars, the biggest stumbling block being its lack of water and ...
- 6,304
7
votes
3
answers
3k
views
Could a spacecraft take off from Earth using nuclear thermal rockets?
If enviromental concern was not taken into account, could you use a nuclear thermal rocket such as NERVA or Pewee to take off from Earth's surface into low Earth orbit?
If not why?
Is a launch ...
- 1
26
votes
2
answers
4k
views
What would the Venus landers look like today?
Between 1966 and 1985, several probes, mostly of Soviet design, successfully landed on Venus. Many of them continued operating long enough to send back audio, images, and various measurements, though ...
2
votes
2
answers
412
views
What was the volume of the Rocketdyne F-1 engine's main combustion chamber?
In the specifications of the F-1 available online, I can find its dimensions, weight, thrust, etc. but I couldn't find what was the volume of its main combustion chamber. Is this information available?...
- 192
14
votes
1
answer
670
views
28V vs. 124V on the ISS
Apparently the US segment of the ISS runs on 124v DC, while the Russian segment is on 28v DC. Why the difference? I understand it is often safer to have several different voltages rather than one, but ...
CommunityBot
- 1
0
votes
1
answer
47
views
Gibbs' method and position vectors' reference frame
As mentioned on this website https://www.studeersnel.nl/nl/document/technische-universiteit-delft/flight-orbital-mechanics-and-propulsion/chapter-05-preliminary-orbit-determination/4604099, we need to ...
- 7,683
0
votes
1
answer
23
views
LEO Satellite Service / Coverage Time Calculation for a Ground User
I want to determine the time interval during which a ground user is in the coverage of a particular LEO satellite. I only have knowledge of the user's geographical location and the satellite's TLE (...
- 7,683
0
votes
1
answer
50
views
TLE propagation, I don't understand which time should I use in (t - t_0)?
I'm trying to plot ground tracks with the help of TLE data. However, there are some equations that contain "times", and I can't understand which time I should use and format. Like for ...
- 7,683
1
vote
2
answers
96
views
What are N and D variables which take part in this Gibbs' method/algorithm for orbit determination
I am trying to make sense of this algorithm, which is the Gibbs method of orbit determination from three position vectors. More specifically, I am trying to understand the equations 5.13 and 5.14.
5....
1
vote
1
answer
124
views
Can a ship's thrusters amplify a gravity assist?
If a ship successfully absorbs a planet's kinetic energy to increase its speed, can it add to that speed by firing its thrusters? Thank you very much.
- 2,209
1
vote
2
answers
151
views
Deorbit ISS vs. Preserve ISS as raw materials for ISM?
Recent news:
NASA Seeks Proposals from US Industry for Station Deorbit Spacecraft (ISS)
NASA has released a request for proposal from U.S. industry for the U.S. Deorbit Vehicle (USDV), a spacecraft ...
- 1,162
14
votes
2
answers
784
views
What's the furthest a probe has travelled from Earth before returning?
Inspired by this question, I've been wondering how far a probe has been from Earth, conducted its mission, then subsequently returned to Earth.
I'm aware of the Hayabusa and Stardust missions, but I'...
- 121k
0
votes
0
answers
140
views
Live_ISS_Stream stopped?
so I've come across this video, 11 hours of ISS transmissions during 2021 ASAT incident by Russia. The description says the footage was archived from this IBM stream site, so I've looked to see if it ...
- 39
4
votes
1
answer
168
views
What were the challenges of an exploration mission to Trojan asteroids?
There are many space probes that flew past asteroids, some came close to it, some orbited and some landed on it and took samples but those asteroids belonged in the main belt. Now, Lucy will become ...
- 124k
90
votes
3
answers
22k
views
Could Apollo astronauts stand up if they fell on the moon?
I was watching old Apollo footage and noted how astronauts on the moon had a very particular gait most likely due to the poor flexibility of the EVA suits, low gravity, and need for safety.
I was ...
- 12.5k
1
vote
0
answers
170
views
Fastest time to Moon for Starship
What is the fastest time to the Moon possible with Starship in the near future, assuming there is orbital refueling?
Is sustained acceleration and then deceleration possible at say 0.25G, to reduce ...
- 313
0
votes
0
answers
57
views
How to read .eph (GPS Ephemeris binary data) sent by the receiver
My GPS receiver can share ephemeris info as binary data. The queried data is having .eph format. I tried to open it in Notepad but seems unreadable (gibberish). Is there any specific software to open ...
- 2,496
-1
votes
0
answers
131
views
What would the maximum height of a building such as a high rise apartment building on Mars?
How many stories tall could a steel frame building be built on Mars?
- 12.5k
8
votes
2
answers
17k
views
Transform ECI to ECEF
I need to transform ECI to ECEF coordinate. Here, I need the formula in math and algorithm. I have looking for the formula in the internet, but I can find one.
I have x, y, z cartesian coord in ECI. ...
- 1
7
votes
2
answers
4k
views
How feasible is a manned flight to Apophis in 2029 using Artemis or Starship?
Apophis will fly by Earth around GEO altitude in 2029. May NASA consider launching an Orion spacecraft on a (sub-)orbital trajectory whose apogee is very close to Apophis so that astronauts can study ...
- 976
-2
votes
0
answers
96
views
How do I make a solid fuel rocket? [closed]
I'm just wondering how to make LH2(liquid hydrogen) in my home lab. I just want to create a small rocket engine. How would I achieve this?
1
vote
0
answers
99
views
Escaping Earth - how could one attempt to find the best solution to this trajectory optimization problem in practice?
If there is a satellite in low Earth orbit, with a limited delta-v budget (but high enough to escape Earth) and limited delta-v-rate (thrust), how could one find an acceleration schedule and ...
- 161
3
votes
3
answers
961
views
Would orbital ring platforms affect the orbit of a planet?
If we built an orbiting platform of sufficient mass (let's say, made from harvested asteroids) that was anchored at both poles of the planet it surrounded, would such an addition to the planet's mass ...
- 3,198
-4
votes
1
answer
182
views
How does SpaceX prevent fuel from cluttering together in zero G [closed]
What is the solution to stop fuel inside starship collecting in center of the tank during zero G flight? Here is a rough sketch of starship with rudimentary diaphragm system to control flow of fuel ...
- 4,414
0
votes
0
answers
44
views
Hypersonic dynamic shift in large vs. small lifting bodies
Background:
Lifting bodies have been tested at small scales, though not during re-entry. For instance: the NASA HL10
Such Lifting-Body designs are seemingly here to stay with craft such as Dreamchaser ...
- 917
10
votes
1
answer
2k
views
Packing Osiris Rex capsule after landing
What was the procedure for packaging SRC Osiris Rex after landing? How to keep it clean, with no dust or sand? Why was it not packed on a clean surface like a table?
- 8,747
4
votes
1
answer
224
views
What is this NASA Spaceflight article trying to explain?
The NASA Spaceflight article Extended Russian EVA complete – conducts satellite deployments contains a very long discussion about the timing of the CRS-12 launch. Had it missed the "single shot launch ...
- 1,162
1
vote
0
answers
42
views
Surface Resource Distribution Across the Orbits of the Saturnian Moons
I've posted questions before related to ISRU and/or resource harvesting in the Saturn system, given how low the velocity change is for inter-moon transfer.
What resources are available to turn into ...
- 149k
11
votes
4
answers
6k
views
Why would astronauts need a wristwatch and a separate timer?
Watching this image used in this question
Why would astronauts in SpaceX's Crew Dragon need two separate timing devices: one portable digital timer, and one wristwatch, rather than carrying into orbit ...
- 4,098
36
votes
2
answers
953
views
Does anyone recognise this differential equation (from Gravity's Rainbow)?
In the novel Gravity's Rainbow by Thomas Pynchon, there is a chapter in which Slothrop (the main character) thinks about this equation:
$$\theta \frac{d^2\phi}{dt^2} + \delta^* \frac{d\phi}{dt}
+ \...
- 149k
9
votes
1
answer
3k
views
What are the movable-plastic-bag-looking things on the nose of Shuttle?
I was watching the last launch of Space Shuttle Atlantis (STS-132) and noticed some objects that moved during the launch. I was curious about what these objects were and why they were positioned that ...
- 1
0
votes
0
answers
81
views
Electric Spacecraft Propulsion [closed]
I'm currently in the electrical design phase of my Pulsed Plasma Thruster (PPT) project, which utilizes teflon as the solid propellant. I'm seeking guidance and any relevant materials or information ...
- 11
1
vote
1
answer
69
views
How to get contact locator events in GMAT using Python
I am trying to write a python script for GMAT to detect contacts between a satellite and a ground station. I have declared the contact locator as such:
...
- 11
1
vote
1
answer
239
views
What network does the Chandra X-ray Observatory satellite use to communicate with Earth while staying in its orbit?
From a NASA fun facts website How do satellites communicate?:
How do satellites communicate?
Satellites communicate by using radio waves to send signals to the
antennas on the Earth. The antennas ...
- 13.6k
17
votes
6
answers
6k
views
What are the considerations for smelting iron and aluminum in space?
Iron and aluminum are the two most common metals in the Earth's crust. While we can't know for sure what we'll find for raw resources when we start building factories in space, if we assume that iron ...
8
votes
1
answer
170
views
First water deluge system?
Does anyone know what the first use of a water deluge system was?
I've done some light googling and discovered that the Titan II ICBM rocket silos (first built in 1962) used a water deluge system, but ...
- 149k
1
vote
1
answer
68
views
GMAT LEO spacecraft simulation
I started using GMAT, I have to design an LEO of an AEOLUS Satellite and I have the TLE of the launching. My question is how do I plug the TLE numbers into the spacecraft section (Keplerian element ...
- 149k
4
votes
2
answers
132
views
How does one use the SEAESRT charging hazard graphic that NOAA provides?
NOAA provides a dashboard for satellite operators. One of the tiles provided is the Charging Hazard graphic included below:
I'm not quite sure how is this infographic used?
How do satellite operators ...
14
votes
4
answers
2k
views
How does Spinlaunch manage the counterweight right after launch?
Spinlaunch has successfully launched a suborbital test vehicle from a 1/3 scale demonstrator, see for instance aviationweek.com or space.com.
While spinning up the arm, perfect balance is achieved ...
- 149k
30
votes
1
answer
7k
views
Reasons behind Soviets Using Prolog Programming Language for Buran Space Shuttle?
I was reading a post related to the operating system of American Space Shuttles, then wondered what might Soviets have used. I found a CIA document and several forums saying that Prolog was used in ...
2
votes
1
answer
129
views
How often does a CubeSat leverage its ADCS?
I'm wondering how often an Earth observation-focused CubeSat (6U - 27U) would leverage its onboard Attitude Determination and Control System (ADCS).
Would it be employing its ADCS to optimize every ...
- 196
11
votes
2
answers
892
views
What is this device/object that the SpaceX astronauts are holding?
Watching the SpaceX Demo-2 launch preparation livestream, I saw both Bob and Doug using some sort of little gadget. It looks like a chunky cell phone, or a flat gopro. It appears to have an LCD on the ...
- 39