Now I wish I could say you could handle this easily with a single pattern, but unfortunately, a repetition modifier around captures doesn't produce the desired results:

$_ = 'de ad be ef #junk';
/^(\w\w)(?: (\w\w))*/;
[download]

There's no way around it, this requires a two step approach: Step 1) extract the whole of all the captures, Step 2), split it into parts.

1. The first approach is to use split for step 2:

   $_ = 'de ad be ef #junk';
   /^(\w\w(?: \w\w)*)/;
   my @capture = split ' ', $1;
   [download]

2. Use //g, either in a loop, or in list context.
   1. //g in list context:

      $_ = 'de ad be ef #junk';
      my @capture = /\G(?:^|\ )(\w\w)/g;
      [download]

   2. A loop with //g in scalar context:

      $_ = 'de ad be ef #junk';
      my @capture;
      while(/\G(?:^|\ )(\w\w)/g) {
          push @capture, $1;
      }
      [download]

Be extremely careful with the latter that you don't accidently cause an endless loop. I did, with

/(?:^|\G\ )(\w\w)/g
[download]