# All Questions

14,610 questions
Filter by
Sorted by
Tagged with
18 views

### LVLH frame based on inertial velocity or relative (ground) velocity?

The LVLH frame is widely used in rockets during launch. The space shuttle crew used it in its attitude readings beginning very early after launch, meaning it was very reliable as soon as the rocket ...
9 views

### Precise timing using GPS

Looking at https://gssc.esa.int/navipedia/index.php/GPS_Navigation_Message and other websites, in order for a satellite receiver (which doesn't have other means of getting precise GPS time) to ...
81 views

### Liquid fueled suborbital rockets?

Which suborbital (sounding, balistic, amateur or else) rockets use or used liquid fuel? I could find (with help from A. Rumlin) New Shepard - Blue Origin - RP-1 Spica - Copenhagen Suborbitals - ...
78 views

### What if we launched rockets from space using the slingshot method and centripetal force? Would that be possible?

Would we have to build a orbiting launch station that uses centripetal force to launch the rockets? Or a station that freely floats through space not in a planets orbit? Would something like this ...
39 views

### What was the first satellite with COTS electronics?

Computers and memory, radios, cameras, light sensors, temperature sensors, accelerometers & gyros1, power supplies, power conditioners and converters and battery interfaces can all be put together ...
114 views

### How was an emergency landing site at Diego Garcia used during the Apollo program?

On the current Starlink mission as the 2nd stage passed over the Indian Ocean I heard mention of contact with a ground station at Diego Garcia. Checking that article I found the subsection Space ...
96 views

### Was the famous SPICE package of programs, utilities and data kernels named after “Melange” found on the planet Arrakis?

This question is NOT about a fictional planet: This question is about NASA JPL history and the naming of SPICE. It is not primarily about the fictional planet Arrakis nor the fictional drug Melange ...
69 views

### Where to obtain Appendix B of STS Historic American Engineering Record TX-116?

At the close of the Shuttle program the National Park Service and the Smithsonian (maybe others as well) embarked on a project to document the Space Transportation System as part of their Historic ...
45 views

### How big would a QR code have to be on my roof for a satellite to be able to scan it given today's allowable resolution?

Say, using the Planet Labs satellites Thank you
132 views

### Starship deceleration during belly flop?

Was just wondering what level of deceleration did they get during that belly flop manouver? Updated: Hiya, you're all correct, and I was a tad vague in my question! What I'm after is the vertical ...
2k views

### Why isn't SpaceX's Starship trial and error great and unique development strategy an opensource project?

This may be dumb (for reasons I cannot grasp) and even not related to space exploration at all, so feel free to vote to close this one. Yet obviously some large community of space enthusiasts is ...
4k views

### Would a higher air pressure on the ISS or elsewhere make it easier to “swim” in microgravity?

What if the atmospheric pressure onboard the ISS was 5 atm, 5 times the pressure on Earth and currently on the ISS, while maintaining the breathable oxygen level, e.g. if the additional atmosphere ...
132 views

### Did anything specific happen on the 16 or 22 March 1992 passes of a Lacrosse I surveillance satellite over Tehran?

After reading the question Predicting non-Iridium flares and Why NOSS satellites flare? I found the following page linked in Wikipedia's Naval Ocean Surveillance System. The h2g2 (The Hitchhiker's ...
185 views

### How much will it cost MrBeast to send a HDD alongside the new moon rover?

I saw this mrbeast stream where you could send a pic to the moon and he promises that he has made arrangements with nasa that they (nasa) will pack it up with a new rover to the moon to be launched ...
35k views

### What kind of laptops do ISS astronauts use?

In many videos of the ISS, you can see tethered laptops all over the place. Presumably these are heavily customised for space. What kinds of customisation do they need? Are they off-the-shelf laptops ...
97 views

### How to convert a SPICE SPK kernel into human-readable data (CCSDS “Orbit Ephemeris Message”) using spk2oem tool

SPK2OEM is one of many of SPICE tools available here: https://naif.jpl.nasa.gov/naif/utilities_PC_Windows_32bit.html I am trying to extract ephemeris from one of the SPK files listed here: https://...
166 views

### RS-25E cost estimate but sentence confusing (approximately: help; maybe)?

So recently someone found out that the industry studies for SLS had been FOIAed by a site called government attic. While the other studies are interesting in their own right (check them out honestly), ...
156 views

### “Reading 486” air speed from Challenger disaster: What units?

Some of the last words from the doomed Challenger crew were "reading 486," which the Boston Globe describes as a routine air speed callout. Would this be vehicle speed relative to the air, ...
66 views

### How to know in which quadrant is the RAAN?

Having found the right ascension of the node, for example, \begin{align*} \boldsymbol{\Omega} &= cos^{-1}\frac{N_X}{N} \\ &= \underline{15.60^\circ} \end{align*} How do we know in ...
43 views

### What order were space shuttle roll-pitch-yaw angles displayed in?

The space shuttle had a digital readout of roll-pitch-yaw angles in a chosen frame (inertial, LVLH, or reference). What rotation sequence did they assume in that digital readout? Was it roll-pitch-yaw?...
618 views

### Space shuttle orbital insertion altitude for ISS rendezvous?

What altitude did the space shuttle normal target for orbital insertion on ISS rendezvous missions? In the likely case that there isn't a single typical number: can you give a number the shuttle might ...
124 views

Another question asks why Spirit and Opportunity weren't launched together. My gut response was that multiple-payload launches were less common then than they are today, but I don't actually know if ...
55 views

### What would space shuttle digital attitude display show during flipover

The space shuttle used quaternions for navigation, guidance, and control which don't suffer from the singularities that affect euler angle sequences. Yet, the attitude indicator had a digital readout ...
3k views

### Is the pressurization of propellant tanks necessary for structural integrity?

Propellant tank pressurization is a critical aspect of liquid propellant rocket design. Many designs use high pressure helium, heated and recirculated, however the propellant gases themselves can be ...
273 views

### How can firing a Space Shuttle OMS engine below 21 km cause its nozzle to “collapse”?

This answer to Can the space shuttle use OMS engines during landing? says: No and quotes Section 3.7 of the Orbital Maneuvering System Workbook; OMS 21002 October 10, 2006, Final version, USA006500 ...
297 views
+100

### What might the first deep space telescope using the Sun or Jupiter as a gravitational lens be like?

@SteveLinton's nicely written and sourced answer about using strong gravitational lensing by the Sun or even Jupiter as a kind of telescope to resolve the surfaces of exoplanets is really interesting, ...
29 views

### Timeline of record multiple satellite launches

The Transporter 1 mission has placed 143 satellites into low orbit in one go. The previous record was held by the Indian ISRO PSLV C37 mission with 104 satellites in 2017. Where can I find a complete ...
3k views

### Are there any hand-sized rocket engines?

Are there any rocket engines that are small and light enough to be held in one or both hands? Gas, liquid and hybrid designs are fine but solid motors are excluded (with the exception of solids that ...
101 views

### How do pressure-fed engines stay cool?

Does anyone know how pressure-fed/hypergolic rocket engines cool themselves down? Do they regenerativly cool themselves? Thanks!
15k views

### Highest number of satellites launched on a single rocket

What is the highest number of satellites that have been launched on a single rocket? What were the number of stages used in that launch? (It may be from the past or a future mission)
403 views

### Can the space shuttle use OMS engines during landing?

Can the space shuttle use its OMS engines if the shuttle is short during the runway approach? Is fuel available for use in such a situation and will the engines provide reasonable thrust to get to the ...
78 views

### Displaying spacecraft attitude from rotation matrix or quaternion?

Navigation and guidance systems generally use rotation matrices or quaternions to uniquely specify 3D rotations. But these are not the least bit intuitive, so we like to convert them to Euler angle ...
1k views

### Is it always one nozzle per combustion chamber and one combustion chamber per nozzle?

When I read about engines like the RD-170 they might have a single turbopump feeding multiple combustion chambers, and each combustion chamber has its own nozzle. Is there, or would it be reasonable ...
22 views

### What is the inlet and outlet pressure of Merlin LOX/RP-1 turbopump?

I got the inlet and outlet pressure of Saturn V engines turbopumps here, but I couldn't find the turbopump pressure of the Merlin engine of Falcon 9.
23 views

### Are TVC pyros broken before, during, or after engine ignition? [closed]

I've read that TVC actuators are kept locked with pyro bolts which detonate when the engine is ready to fire. But do they detonate just before ignition, at the same time as ignition, or shortly after ...
98 views

### For deep space missions, how thick must the water filled layer within the ship's hull be to effectively shield against cosmic rays? [closed]

Initially i proposed a 27cm thick barrier. But im not really sure thatll be enough
66 views

### What is range angle?

In several papers on powered explicit guidance, I've come across the term "range angle." I'm familiar with inclination and azimuth angles, but range angle is new to me. A quick search gave ...
28 views

### Space Shuttle I-Loaded Acceleration Profiles?

Documentation on the space shuttle's GNC systems mentions that in the high-Q region, the flight control system compared the actual transverse accelerations with I-Loaded acceleration profiles, then ...
215 views

### Have the Starlink precursor Tintin satellites been talking to each other? If so, how?

Tintin A and B are the first two exploratory and testing spacecraft for SpaceX's Starlink program. It looks like they are in very similar orbits in both space and time, and are probably that way so ...
114 views

### What company has the most satellites in orbit?

Ars Technica's SpaceX to offer Starlink public beta in six months, Musk says says Meanwhile, SpaceX launched another 60 Starlink satellites yesterday. The launch, as Musk noted, gives SpaceX "...
53 views

### What is the practicality of using sub-cooled propane in combination with HTP in an amateur engine design? [closed]

Using sub-cooled propane, at approximately -90°C (b.p. -42°C at STP) in combination with >80% hydrogen peroxide, can any meaningful gains be made, and could the mixture be used in a low budget ...
37 views

### Design a cold gas ACS nozzle

I have the total thrust required to be F=16.9 KN. I am using nitrogen gas, and the stored temperature in the nitrogen gas cylinder is 155 bars with a temperature of 325k. How would I design the nozzle ...
33 views

### Active magnetic protection against cosmic radiation - Can anyone provide articles or summarize the latest developments?

A European project purports to have a practical magnetic shield for cosmic rays, based on four MgB2 toroidL coils1 oriented around the spacecraft like the lines of longitude around the globe. I can't ...
49 views

### What is the first time that two satellites were launched together as the same payload?

Below I've assembled some research into the question of which launch is actually the first to carry two satellites into orbit, but so far I think the results are inconclusive. So despite there being ...
744 views

### How to drink water on Mars?

There are craters filled with water on Mars as shown below. If fresh water is found, how would astronauts drink the water? Can the Apollo a spacesuit food/drink port be used to equalize the pressure ...
66 views

### How would an n-body numerical orbit simulator use hierarchy in its Jacobian?

This question is about techniques to calculate orbits. The Github post On the dynamical stability of Principia's modified Jool system (cited in this answer) says: Principia computes the trajectory of ...
63 views

### Why would photon pressure be needed to keep ParkinsonSAT Spinning?

This answer to Can a satellite work like a radiometer? says (in part): ...the US Naval Academy cubesat ParkinsonSAT was designed with four faces asymmetrical, with solar panels offset to one side ...
107 views

### Missions failed before launch

The Falcon 9 - Amos-6 - mission in 3 September 2016 failed before launch - the rocket exploded during the static fire test. Some lists contain such missions but others don't - like for example ...