For ballistic re-entries, how large can capsules get? Do they perform better or worse as they get larger? Is the idea of a 50 passenger re-entry capsule silly?
Apollo return capsule was about 4 meters in diameter. Soyuz SA is 2.17 meters. And the 7 crew Dragon is 3.7 meters. [wiki]
If launch a much larger diameter capsule 50 passenger return is
The Shuttle orbiter [not a capsule] could have put a passenger bus
in it's cargo bay.
Shuttle Orbiter Specifications:
Gross Liftoff Weight: 240,000 lb
Empty Weight: 172,000 lb
Maximum Landing Weight: 230,000 lb
Maximum Payload: 55,250 pounds (25,060 kg)
Payload Bay dimensions: 15 ft by 60 ft (4.6 m by 18.3 m)
If allow 400 lbs per passenger. 50 is 20,000 lb. Of course allowing for them to live in orbit for a day or two to weeks is a different question as is
the idea of how one entertains such a crowd.
I would guess the shuttle orbiter is about equal to capsule of 20 meters in diameter.
But total mass of shuttle orbiter [Maximum Landing Weight: 230,000 lb] gets you lot potential seats. So if get 20 meter diameter capsule into space, one could land hundreds of passengers.
I believe largest current fairing is around 5 meters in diameter.
"The standard payload fairing sizes are 4 or 5 meters in diameter and of various lengths, are made by RUAG Space. Fairings sizes as large as 7.2m in diameter and up to 32.3m in length have been considered."http://en.wikipedia.org/wiki/Atlas_V
And if wanted it, one could probably get a fairing diameter as much as 10 meters in diameter. And btw, if you be serious about Mars exploration, you need such fairing sizes.
So if had 50 passengers to return, one could get 10 meter diameter fairing on any of the existing rockets and a capsule which was 10 meter in diameter could land 50 people. Perhaps even with 7.2 meter one could stack 50 people into it.
7.2 meter is about 53 square meter
And 3.7 meters [Dragon] is 14 square meter.
Probably easier with 10 meter diameter. One could land a 20,000 lb payload with 7.2 diameter- but with 50 people there probably great value in having a "calmer, more spacious descent".