Begin by ensuring that your environment is ready for the task. Install Python, if not already installed, as it will be used to pull data from the SpaceX API and insert it into PostgreSQL. Additionally, ensure PostgreSQL is installed and running on your system. You can download Python from [python.org](https://www.python.org/) and PostgreSQL from [postgresql.org](https://www.postgresql.org/).

Open the PostgreSQL command line or use a GUI like pgAdmin to create a new database. This will serve as the destination for the SpaceX data. Use the command:
```sql
CREATE DATABASE spacex_data;
```
Replace `spacex_data` with your preferred database name.

Determine the structure of the data you want to store and create the appropriate tables in your PostgreSQL database. For example, if you're storing launch data, you might create a table with columns for launch date, rocket name, and mission details. Use SQL commands like:
```sql
CREATE TABLE launches (
id SERIAL PRIMARY KEY,
launch_date TIMESTAMP,
rocket_name VARCHAR(255),
mission_details TEXT
);
```

Use Python to access the SpaceX API. The API provides endpoints for various data types, such as launches, rockets, and capsules. Use the `requests` library to make HTTP GET requests to the API. Install the library using:
```bash
pip install requests
```
Then, fetch data using:
```python
import requests

response = requests.get('https://api.spacexdata.com/v4/launches')
data = response.json()
```

Process the JSON data received from the API to match your database schema. This can involve extracting necessary fields and converting data types. For example:
```python
processed_data = [
{
'launch_date': launch['date_utc'],
'rocket_name': launch['name'],
'mission_details': launch['details'] or 'N/A'
}
for launch in data
]
```

Use Python's `psycopg2` library to connect to your PostgreSQL database and insert the processed data. Install the library using:
```bash
pip install psycopg2-binary
```
Then, insert the data:
```python
import psycopg2

connection = psycopg2.connect(
dbname='spacex_data',
user='your_username',
password='your_password',
host='localhost'
)
cursor = connection.cursor()

for launch in processed_data:
cursor.execute(
"""
INSERT INTO launches (launch_date, rocket_name, mission_details)
VALUES (%s, %s, %s)
""",
(launch['launch_date'], launch['rocket_name'], launch['mission_details'])
)

connection.commit()
cursor.close()
connection.close()
```

To keep your database updated, automate the data transfer process. Write a script that fetches and inserts data at regular intervals. Use a task scheduler like `cron` on Unix-based systems or Task Scheduler on Windows to run your script at desired times. For example, to run the script every day at midnight using `cron`, add the following line to your crontab:
```bash
0 0 * * * /usr/bin/python3 /path/to/your_script.py
```
Replace `/path/to/your_script.py` with the path to your Python script.