marsokod

@marsokod@lemmy.world

• ⁨Comment⁩ on ⁨Why are people impressed with SpaceX?⁩ ⁨⁨3⁩ ⁨weeks⁩ ago⁩:

  There are a few things that are different from what NASA has done in the past:

  1. SpaceX Rocket is the most powerful rocket ever, surpassing everything that NASA or anyone else has ever done.

  2. they are landing the rockets, with the aim of being able to recover them. If you skip the technicality that SpaceX first stage is suborbital but is part of an orbital launcher, that makes SpaceX the only entity who has achieved that, with some comparison to the Space Shuttle and Buran, though both where losing significant sections of the initial launcher, with very difficult repairs once on the ground.

  3. the cost of the launcher. In terms of capabilities, NASA’s SLS is probably close to Starship. However, it costs around $2B/launch, and nothing is recoverable. Starship is meant for low cost. It is estimated that the current hardware + propellant for a single launch is under $100M. With reusability, a cost per launch under $10M is achievable in the mid term (~10 years I would say) once the R&S has been paid (~$1.4B/year at the moment, I would guess the whole development for Starship will be $10-20B, so same if not less than SLS).

  4. the aim for high speed reusability - SpaceX aim is to launch as much as possible, as fast as possible, with the same hardware. While it is a bit early to understand how successful they will be (Elon was saying a launch every 1hr, which seem to be very optimistic, I would bet 6-12hrs to be more achievable). That was NASA’s original goal for the Space Shuttle, and they failed that.

  5. finally, orbital refueling means you have a single vehicle that can basically go anywhere in the inner solar system without much issues, and minimal cost.

  Also, what gets people excited is the prospects of what this enables. A 10-100x decrease in the access to orbit changes completely the space economics and opens a lot of possibilities. This means going to the Moon is a lot simpler because now you don’t need to reduce the mass of everything. This makes engineering way easier as you do not need to optimise everything to death, which tends to increase costs exponentially. And as for Mars, Starship is what makes having a meaningful colony there possible. Doing an Apollo like mission on Mars would have been possible for decades, but at a significant price for not much to show for. With cheap launch, you can just keep sending hardware there.

• ⁨Comment⁩ on ⁨World first UK prototype could pave the way for constant energy all the time - from space | Science & Tech News⁩ ⁨⁨6⁩ ⁨months⁩ ago⁩:

  To complete that good answer, basically satellites in GEO will experience eclipses 2x21 days per year (around March and September). The eclipse duration during these period will vary from 0 to 70minutes and then down to 0 again, with one eclipse per day, around midnight.

  So your solar plant in space will work 100% of the time 320+ days a year, and will have a small down time that can be up to an hour in the middle of the night otherwise. Not perfect but actually very manageable with a little bit of storage on the ground.

  Overall, the main concern with these systems is the total cost, including launch cost. It is hard to tell if it will be competitive with solar + battery on the ground.

• ⁨Comment⁩ on ⁨Do bike tires increase pressure in summerm⁩ ⁨⁨7⁩ ⁨months⁩ ago⁩:

  To do the math, an assuming constant volume, a 30C increase corresponds to around 10% increase in pressure. That’s well within the margins of the tyre even if you go to the max rated.

  If you then consider deformation and most importantly leakage over several weeks, this is a non-issue.

• ⁨Comment⁩ on ⁨Energy bills in Great Britain to rise by 5% from January as cap hits £1,928⁩ ⁨⁨11⁩ ⁨months⁩ ago⁩:

  This.

  I don’t mind if they use the average household number in the title or header, that’s understandable. But such an article should have the actual values somewhere.

• ⁨Comment⁩ on ⁨Four men charged over theft of £4.8m gold toilet from Blenheim Palace⁩ ⁨⁨11⁩ ⁨months⁩ ago⁩:

  That will be a nice explanation when they arrive in prison.

  • What are you here for?
  • I stole a shitter and got caught…
• ⁨Comment⁩ on ⁨‘The quotes were £5,000 or more’: electric vehicle owners face soaring insurance costs⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  I would be tempted to say that with EV cars still being biased for the higher quality cars, and with Tesla still having a majority of the market, this should push the average cost of repair. Not sure when Tesla will fix their repair chain issues.

• ⁨Comment⁩ on ⁨Why don't we pump seawater into deserts to revive them?⁩ ⁨⁨1⁩ ⁨year⁩ ago⁩:

  Even as a slave, the cost of a human work is magnitudes above the cost of using a pump with petrol. A slave may be able to output ~1kWh per day, that’s mostly a few 10s of cents anywhere. Can you feed anyone on that?