Updating your Credit Card information for your active subscription is easy.
First Log in to the Launchpad at https://go.itelescope.net/default.aspx
Next, Locate the drop down menu pictured below and select Update My Details
Once selected, it will take you to your account management page where you can update your address, email address, and update your credit card. You do this by selecting the link pictured below:
This will bring you to this page below. You will want to click "Update".
From there you will need to select either Credit Card or Paypal, and complete the on screen form (for Credit Card) or select "Continue" for PayPal, where you will be prompted to sign in to your Paypal Account. Keep in mind that this will charge you $1.00 USD to verify the new card information.