# Tag Info

-1

Upon reaching Low Earth Orbit, the Shuttle has Used most of the fuel it took to get up their. It now rides solely on inertia and orbits the Earth. The Shuttle Orbiter weighs over 80 tons! The Apollo spacecraft weighted 25 tons including the lander. The shuttles weight compared to it's volume negates any fuel carrying capacity to escape orbit and go to the ...

0

It all depend how safe and accurate you want to be. But they used a supercomputer, and we would use a supercomputer today too. There are 2 way to handle it : Compute everything : you have an insane amount of variable to account for, too many too list. Let's just say that, beside the gravity effect of many objects, you also have to handle relativity (even if ...

1

A computer is a "broad term" Calculations are necessary for all factors of momentum, energy, thrust, power, energy management, etc. The point is, NASA had computers on it's early spacecraft. The Gemini missions had a computer as well for ascent, descent, flight and orbital maneuvering. However, NASA realized computational power was premium so they ...

0

For more details on how the Apollo guidance computer was designed and built, and the people who did it, take a look at We Hack the Moon, the 50th anniversary website of the MIT lab that led the work. During the open to the public museum display in their lobby from June to October of 2019, they had a mockup of the LEM that let you try to land it yourself, ...

1

It's all hard. Try operating a basic ascent to orbit simulator where YOU control eg just the thrust. See how many attempts it takes you to reach orbit. Decades ago I did this many, many .... times. Even with vast experience, achieving orbit was a pleasant surprise.

1

From Tons of Water in Asteroids Could Fuel Satellites, Space Exploration: But asteroids will certainly be more accessible than the moon, another potential source of space-based water-rich minerals. According to Rivkin, landing safely on the lunar surface takes more than a hundred times the change of velocity required to land on an asteroid. Similarly, ...

0

Interesting that some simple astrodynamical problems indeed can be solved without a computer, just by pen and using high-school algebra. For example mass of payload a rocket launches can be calculated by Rocket equation. The caveat is we don't account for 1)atmosphere drag and 2)non-straight trajectory of rocket. Also orbit transfer can be calculated easily, ...

3

As just one example consider the Lunar landing. If you think about a vehicle sitting on top of a rocket, with the thrust vector of the rocket passing through the centre of mass of the system for a moment you'll realise that it's not stable: there's nothing making it want to point in any particular direction. But you need it to face in some very particular ...

26

Your spacecraft would need to be several orders of magnitude larger than the Saturn-Apollo. No human pilot has successfully performed a rendezvous without a computer. Note that rendezvous is bringing two spacecraft close together in orbit, position, and velocity. Docking is the actual physical contact between two spacecraft. The latter can and often is ...

0

According to this article, the nave & guidance computer had 36K of ROM, and 2K of RAM. https://history.nasa.gov/afj/compessay.html It lists 30 different “programs” that it could run. The programs probably measure things like temperature, pressure, gyroscopes, etc. as input. The software then decides how to do motor control to keep the vehicle stabilized ...

23

“Do I have a very naive concept of space travel?“ - honestly, yes you do. Here is an excerpt from Don Eyles’s wonderful book Sunburst and Luminary: An Apollo Memoir: Guidance would be processed every two seconds, repeatedly correcting and refining the trajectory based on new data from navigation. Into the guidance equation, with each turn of the crank, went ...

5

The only reason near-Earth asteroids still have water is that it's bound up in hydrated minerals where it's become part of the crystal structure of those minerals. Freeing it from those minerals requires baking it out of at high temperatures (up to around 500 °C), the most easily extractable volatile ices are all long gone due to heat from the sun. In ...

46

Assuming this isn't a troll question and you are serious about wanting to know what computers are used for in spaceflight (prior to 1988), NASA has a great resource for you: Computers in Spaceflight (PDF, 494 Mb) From the introduction: Computers are an integral part of all current spacecraft. Today they are used for guidance and navigation functions such as ...

7

I don't understand why a computer was needed at all, either on the ground or inside the space craft. As Ben (PearsonArtPhoto) pointed out, computers have always been a part of launching rockets. By no means an optional one. Computers are needed to avoid collisions with the debris around earth, to auto-pilot spacecrafts and to monitor mission data (sensors, ...

27

First of all, the ground team could have, and in fact did, do most of the orbital navigation remotely. This report mentions the fact that the on board computer was secondary for Apollo 8, with primary being systems from the ground. The spacecraft did have to do a few things, including making some realtime adjustments during the landing based on the actual ...

0

If the government would decide to bring lots of rocks from various places on the Moon, a private company only needs to offer to do this cheaper. Such a need may happen while planing a long term Lunar base that would attempt to utilize at least some resources from the surrounding rocks. The actual price for the rock samples may be high and not relevant to ...

5

So the basic fact is that the delta-V from LEO to LLO (low lunar orbit) using a high-thrust system is about 4 km/s and using a low thrust system it's about 8. source So, using something like a vacuum raptor engine ($I_{sp}$ 382s) you need a mass ratio of about 2:1. That is, for every ton you want to deliver to LLO you need 2 tons of methalox in LEO. Using ...

2

I don't think it's possible to make a profitable Lunar sample return mission because each bit of Moon you bring back devalues all the other Moon rocks. Additionally, unlike other rare collectables like fine art, any reasonable (and wealthy) investor would know that the only way Moon rock prices will go in the future is down. To illustrate, let's look at a ...

Top 50 recent answers are included