Parker Solar Probe preview: 10 hot facts about NASA's cool mission
to the Sun

http://www.planetary.org/blogs/jason...e-preview.html

This weekend, NASA’s Parker Solar Probe spacecraft leaves Earth on
a mission to touch the Sun.

What's the reason for the hydrogen burp upon take off?

[Sorry, but you need to be specific about just what "hydrogen burp"
you're referring to.]

Open the link and find "hydrogen" therein.