In article ,
says...

On 2019-06-08 09:40, Jeff Findley wrote:

That's not how this works. The reentry burn will be timed such that it
avoids all tracked objects below the reentering vehicle. This isn't
that hard.

Doesn't that preclude precise landing for ballistic objects such as
capsules since they have to time re-entry burn for "traffic" at 340km
altitiude instead of timing it to land next to the recovery ship?

Not really. You need wide open spaces (or ocean) to land a capsule
anyway. All you need to do is to predict when you're going to do the
burn (based on when you have a clear path down). This determines
precisely where you're going to land (splash down). So you preposition
your recovery forces at that location. If you have a backup landing
burn time, you do the same for the backup recovery forces.

Also, capsules do have the capability of producing hypersonic lift.
Apollo needed that lift in order to stay in the upper atmosphere longer
than a purely ballistic capsule would. That hypersonic lift can be used
to produce some crossrange capability. So even a capsule can aim for a
predetermined landing point. Look at the landing accuracies of the
Apollo missions for an idea of how accurate this can be, even with 1960s
technology.

This isn't that hard.

And for powered landings, doesn't that require much more fuel/cross
range in order to paliate for doing a re-entry at a sub=obtimal time in
order to avoid the traffic?

No. Crossrange is achieved mostly via hypersonic lift. That's how the
space shuttle did it (those big delta wings) and it was not a "powered"
landing. Dreamchaser is a lifting body for that same reason. Even
Starship will have hypersonic lift mostly from the body and partly from
its relatively small aerodynamic surfaces. So no additional propellant
necessary.

Jeff

--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.