Is it possible to copy a schema from a cluster to another cluster?

A common pattern for sharing data between production and a test environment is to use Redshift Data Sharing.

https://docs.aws.amazon.com/redshift/latest/dg/datashare-overview.html

Your production cluster will become the "producer" and your test environment will become the "consumer". On the consumer, execute:

select current_namespace;

Next, on the producer, say you want to share the prod schema.

create datashare prod_share set publicaccessible true;
alter datashare prod_share add schema prod;
alter datashare prod_share add all tables in schema prod;
grant usage on datashare prod_share to namespace '<consumer namespace>';

Now, on the consumer, you execute the following:

select producer_namespace from svv_datashares where share_name = 'prod_share';

Use this output to execute this command:

create database prod_db from datashare prod_share namespace '<producer_namespace>';

You can execute your tables with three part notation. For example:

select * from prod_db.prod.sales;

You can also create an external schema to use two part notation.

create external schema ext_prod from redshift database prod_db schema prod;

Now you can execute this:

select * from ext_prod.sales;

This is far quicker for making the production data available in your test environment and doesn't require making another copy of it. As soon as the data is updating in prod, it is also available in test through Data Sharing.