44 votes
Accepted

Why create a production line for the SpaceX Starship?

Musk is creating a Starship "production line", because obviously, he wants a lot of Starships. This aligns with the company's goal of "making humanity a multi-planetary species". As for "where is ...
  • 15.1k
23 votes

Why create a production line for the SpaceX Starship?

Bob Zubrin, of Mars Direct fame, has been critical of the SpaceX Mars plan. He suggests that it makes no sense to send a full Starship too Mars, instead use it to launch the Mars vehicle and just use ...
  • 76.9k
12 votes
Accepted

Why have no reusable launch technologies been developed?

Mass fraction and Tsiolkovsky's rocket equation make for major hurdles. Mf, or the ratio of propellent to dry mass is given by: $Mf=1-e^{-delta V/V_{exhaust}}$ To climb out of a steep gravity well ...
  • 15.2k
8 votes

Why have no reusable launch technologies been developed?

The basic reason is it that it takes a lot of velocity to put an object in orbit. For example the orbital velocity at LEO is around 7.8 km/s. What this necessarily means, is that the final stage of ...
  • 4,173
8 votes

How much of a commercial space launch can be insured?

You may want to read: Legal Aspects of Space Commercialization - K. Tatsuzawa. A few quotations follow... Costs have been insured: In 1982, ESA insured the Marecs-A and B satellites for \$90 ...
  • 4,863
8 votes

When the moon rock heats up to 600°C, does only Helium comes out?

Lunar regolith may contain not only the lightest noble gas helium, but also hydrogen and other noble gases like neon, argon, krypton and xenon. The concentration of helium is much higher than that of ...
  • 47.7k
7 votes
Accepted

Orbit Guardians - bs, right?

I'm not sure what altitude they are aiming for at periapsis, but the $\Delta V$ to go from an 800x800km to 800x100km orbit is 194 m/s, and the $\Delta V$ to go from a 900x900km orbit to a 900x50 km ...
  • 711
6 votes
Accepted

Why is the Space industry expected to flourish and grow in the near future?

Private companies have been trying to get into the launch business since the 80s (ORTRAG in Germany since the 70s), usually turning into a financial disaster for the investors. Several things have ...
  • 4,027
6 votes

Do chemical engineers play a significant role in space exploration?

Yes a chemical engineer is a huge asset in space exploration. Anyone who says otherwise doesn't actually know what a chemical engineer learns. Chemical engineers are essentially mechanical engineers ...
  • 61
6 votes

Do chemical engineers play a significant role in space exploration?

I would say chemical engineers play less of a role in space exploration than aero/astro, mechanical, software, and electrical engineers. I'll try to back this up with evidence before I share my ...
4 votes

Can one put small items in orbit, cheaply?

Practical roadblocks to getting a payload that small into orbit: IIRC nobody offers this service for random small objects. The space industry has more or less standardized on the cubesat standard, ...
  • 122k
4 votes
Accepted

Can one put small items in orbit, cheaply?

That \$3000 per kilogram (\$2000/kg for launch with a reused rocket) assumes a large payload, resulting in a launch cost in several tens to a few hundreds of millions of dollars. The price one has to ...
  • 65.9k
4 votes

Is there a comprehensive list of NASA contractors with a list of projects that they are assigned to do?

You can see all the external spending by Agency for the government at usaspending.gov, Just do an advanced search limiting the awarding agency to NASA. Edit: Search links go stale after a while, here ...
  • 5,088
4 votes

"Lunar vacuum cleaner": Design considerations for regolith dust suction system in exospheric conditions

You cannot vacuum in a vacuum, if you want to use a pressure differential to move dust on the moon you will have to supply the gas yourself so it's no longer a vacuum. You could set up a system which ...
  • 19k
3 votes
Accepted

"Lunar vacuum cleaner": Design considerations for regolith dust suction system in exospheric conditions

Have a look at this paper, which discusses using magnets to collect the regolith in tubes similar to a maglev system. It also claims that the very fine dust particles can remain electrostatically ...
  • 458
3 votes

Can one put small items in orbit, cheaply?

The lowest price I have seen for a launch vehicle to place an object in Low Earth Orbit is the Vector-R by Vector Systems. This rocket has a maximum payload of 63 kilos. The cost for a launch is 1.5 ...
  • 1,054
2 votes

Orbit Guardians - bs, right?

Sounds perfectly plausible. As the other answers have shown, you need roughly 200 m/s delta V to reliably and quickly deorbit such a droplet. For every gram of mass in a droplet, you need to deliver ...
  • 1,410
2 votes

Orbit Guardians - bs, right?

Orbit Guardians - bs, right? Scary? Yes! But no, not necessarily 100% bs. Answers to How hard do you have to throw something off the ISS to make it deorbit? are in the "ballpark" of 90 m/s (...
  • 148k
2 votes

How many people work in the Chinese space program?

While living in China (2004 to 2007), I overheard that China was hiring every space engineer its universities were producing every year. So, at the time, I heard that their center in Gansu province ...
1 vote

What resources could be gained from asteroid mining that would be worth the effort?

Not a single poster has mentioned cobalt. Chondritic metal is an alloy of siderophiles (“iron-loving” elements), the next after the host iron being nickel, then cobalt. Nickel is not particularly ...

Only top scored, non community-wiki answers of a minimum length are eligible