From my novice understanding, weather balloons will routinely reach altitudes
of 65kft?
If (say) that was the height you could achieve for the rocket launch; the 3
things that a balloon launch buys you is (1) obviously reduced drag (2)
significant additional propulsion performance from the utilisation of a higher
expansion ratio and (3) potentially significant increases in mass fraction from
lower operating chamber pressures (which might be counter-helpful for coasting
though).
Saying that, balloon launches are generally a major PITA and not worth the
hassle.
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of roxanna Mason
Sent: Tuesday, 2 March 2021 10:20 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Mini-rocket to space?
The point is 40KFt is at commercial jet altitudes and some business jets like
the Lear 24 service ceiling is 51KFt. Probably can go higher but 51K is chosen
because any higher death would result in a decompression event, even with
oxygen blood boils at body temp.
I think the point has been made that 40KFt drag is far from negligible.
Ken
On Mon, Mar 1, 2021 at 2:46 PM Henry Spencer <hspencer@xxxxxxxxxxxxx
<mailto:hspencer@xxxxxxxxxxxxx> > wrote:
On Mon, 1 Mar 2021, roxanna Mason wrote:
Drag is quite significant at 40,000 ft...
Right and the SR-70 flys fine at 100KFt...
...and most meteors burn up at even higher alt.