Yes, it is possible to change the text import wizard defaults in Excel 2003. Here are the steps to do so:

1. Open Excel and click on "Data" in the top menu bar.
2. Select "Import External Data" and then "Import Data" from the drop-down menu.
3. In the "Text Import Wizard" window that appears, select the file you want to import and click "Open."
4. In the first step of the wizard, select "Delimited" as the file type and click "Next."
5. In the second step of the wizard, select the delimiter you want to use (in this case, space) and make sure it is highlighted in the preview window. Then click "Next."
6. In the third step of the wizard, you can choose to format the data in each column as "General," "Text," "Date," etc. Make your selections and click "Finish."
7. In the "Import Data" window that appears, select where you want to import the data to (e.g. a new worksheet) and click "OK."

To make these settings the default for all future imports, follow these additional steps:

1. After completing the text import, go to "Data" in the top menu bar and select "Get External Data" and then "From Text" from the drop-down menu.
2. In the "Text Import Wizard" window that appears, make sure the settings you want to use are selected (e.g. "Delimited" and "Space" as the delimiter) and then click "Finish."
3. In the "Import Data" window that appears, select where you want to import the data to (e.g. a new worksheet) and click "OK."
4. Close Excel and then reopen it to make sure the new defaults have been saved.