Not sure why this thread is zombified, but since it is:Why bother with existing mountains? Build your own.Open frame towers can be built taller than the tallest buildings for orders of magnitude lower costs. For a long time, antenna masts had to be excluded from "tallest building in the world" records, because of they always won. (We don't really need tall antennas any more, so buildings are back in front.)For the price of Burj Khalifa, and with no exotic materials, you could go many, many times taller with a simple open frame tower. Above the bulk of the atmosphere, taller than any mountain. String many such towers in a row near the equator and hang a long platform from the top like a suspension bridge, but upwardly sloping towards the east. Run a rail up the length. Launch a rocket on a sled on the rail. Perhaps the "first stage" would be permanently mounted to the sled, braking before the end, fully and immediately reusable. "Second" stage would ignite during the loft towards apogee after it leaves the end of the platform.Sure it would cost billions. And billions. But how much has SLS cost so far?
For the price of Burj Khalifa, and with no exotic materials, you could go many, many times taller with a simple open frame tower.
Sure it would cost billions. And billions. But how much has SLS cost so far?
If we consider reusable rockets, the F9 uses the thick atmosphere to slow down. What’s the fuel penalty for F9 to land at 19,000 feet?And I always thought the point of Kilimanjaro was to rocket sled up the slope and launch already at some speed.
the density of air at 18km seems to be about 1/10 of that at sea level. So this concept would get you past 90% of the air?!
Back to reality.
Reviving this old thread!Does anyone know of any threads that consider the effect on this idea of tunneling (a la BoringCompany) straight down into the mountain as deep as you'd like to go with the intent to then evacuate said tunnel of air for a launch, thus eliminating air resistance for the first 18km of the 100km? The first 18km also having the highest density of air compared to the rest of the 82km distance to space. Per this link: https://upload.wikimedia.org/wikipedia/commons/9/9d/Comparison_US_standard_atmosphere_1962.svg , the density of air at 18km seems to be about 1/10 of that at sea level. So this concept would get you past 90% of the air?!One step further, the "first stage" could be integrated into the tunnel via a vertical electric sled that accelerated the LV as much as possible and stayed in the tunnel. Some type of system would need to be employed to keep the air out during the LV's trip through the tunnel, as well as release the LV out the end, but doesn't seem like an insurmountable obstacle.
Reviving this old thread!Does anyone know of any threads that consider the effect on this idea of tunneling (a la BoringCompany) straight down into the mountain as deep as you'd like to go with the intent to then evacuate said tunnel of air for a launch, thus eliminating air resistance for the first 18km of the 100km?
Don't most designs have a mixed exit technology setup, with a primary physical airlock door, and a plasma window that the projectile/spacecraft passes through?
You cannot easily both keep the air out and also let the rocket outYou would need some kind of huge air-tight doors, but the millisecond you start opening the doors, the tunnel starts to pressurize at huge speed, and the rocket hits a huge wave of air dropping very fast from the opening. Some kind of huge airlock might help and decrease the mass of the air in the wave, but flying through an airlock at very high speed does not sound very safe..
Reviving this old thread!
Quote from: 2008rlctx on 06/08/2018 08:44 pmReviving this old thread!Please, please, please, let bad ideas die!
Quote from: 2008rlctx on 06/08/2018 08:44 pmReviving this old thread!Does anyone know of any threads that consider the effect on this idea of tunneling (a la BoringCompany) straight down into the mountain as deep as you'd like to go with the intent to then evacuate said tunnel of air for a launch, thus eliminating air resistance for the first 18km of the 100km? You cannot easily both keep the air out and also let the rocket outYou would need some kind of huge air-tight doors, but the millisecond you start opening the doors, the tunnel starts to pressurize at huge speed, and the rocket hits a huge wave of air dropping very fast from the opening. Some kind of huge airlock might help and decrease the mass of the air in the wave, but flying through an airlock at very high speed does not sound very safe..
Let it burst through several bladders of reinforced cellophane or something similar.
BTW, Kilimanjaro is a world heritage site. It won't be the launch site mountain. Something in the Andes would fit the bill nicely though.
Quote from: Asteroza on 06/14/2018 12:00 amDon't most designs have a mixed exit technology setup, with a primary physical airlock door, and a plasma window that the projectile/spacecraft passes through?Out of curiosity, what's the largest plasma window anyone has produced?[edit: My reason for asking is that looking around the googles, the diameter numbers are typically given in single-digit millimetres, not multiple metres.]